WorldWideScience

Sample records for solder bonding chips

  1. Fluxless flip-chip bonding using a lead-free solder bumping technique

    Science.gov (United States)

    Hansen, K.; Kousar, S.; Pitzl, D.; Arab, S.

    2017-09-01

    With the LHC exceeding the nominal instantaneous luminosity, the current barrel pixel detector (BPIX) of the CMS experiment at CERN will reach its performance limits and undergo significant radiation damage. In order to improve detector performance in high luminosity conditions, the entire BPIX is replaced with an upgraded version containing an additional detection layer. Half of the modules comprising this additional layer are produced at DESY using fluxless and lead-free bumping and bonding techniques. Sequential solder-jetting technique is utilized to wet 40-μm SAC305 solder spheres on the silicon-sensor pads with electroless Ni, Pd and immersion Au (ENEPIG) under-bump metallization (UBM). The bumped sensors are flip-chip assembled with readout chips (ROCs) and then reflowed using a flux-less bonding facility. The challenges for jetting low solder volume have been analyzed and will be presented in this paper. An average speed of 3.4 balls per second is obtained to jet about 67 thousand solder balls on a single chip. On average, 7 modules have been produced per week. The bump-bond quality is evaluated in terms of electrical and mechanical properties. The peak-bump resistance is about 17.5 mΩ. The cross-section study revealed different types of intermetallic compounds (IMC) as a result of interfacial reactions between UBM and solder material. The effect of crystalline phases on the mechanical properties of the joint is discussed. The mean shear strength per bump after the final module reflow is about 16 cN. The results and sources of yield loss of module production are reported. The achieved yield is 95%.

  2. Development of gold based solder candidates for flip chip assembly

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hald, John; Hattel, Jesper Henri

    2009-01-01

    Flip chip technology is now rapidly replacing the traditional wire bonding interconnection technology in the first level packaging applications due to the miniaturization drive in the microelectronics industry. Flip chip assembly currently involves the use of high lead containing solders...

  3. A flip chip process based on electroplated solder bumps

    Science.gov (United States)

    Salonen, J.; Salmi, J.

    1994-01-01

    Compared to wire bonding and TAB, flip chip technology using solder joints offers the highest pin count and packaging density and superior electrical performance. The chips are mounted upside down on the substrate, which can be made of silicon, ceramic, glass or - in some cases - even PCB. The extra processing steps required for chips are the deposition of a suitable thin film metal layer(s) on the standard Al pad and the formation of bumps. Also, the development of new fine line substrate technologies is required to utilize the full potential of the technology. In our bumping process, bump deposition is done by electroplating, which was chosen for its simplicity and economy. Sputter deposited molybdenum and copper are used as thin film layers between the aluminum pads and the solder bumps. A reason for this choice is that the metals can be selectively etched after bumping using the bumps as a mask, thus circumventing the need for a separate mask for etching the thin film metals. The bumps are electroplated from a binary Pb-Sn bath using a thick liquid photoresist. An extensively modified commercial flip chip bonder is used for alignment and bonding. Heat assisted tack bonding is used to attach the chips to the substrate, and final reflow joining is done without flux in a vacuum furnace.

  4. Instantaneous fluxless bonding of Au with Pb-Sn solder in ambient atmosphere

    International Nuclear Information System (INIS)

    Lee, T.K.; Zhang, Sam; Wong, C.C.; Tan, A.C.

    2005-01-01

    A fluxless bonding technique has been developed as a method of flip-chip bonding for microelectronic packaging. The fluxless bonding technique can be achieved instantaneously in an ambient environment between metallic stud bumps and predefined molten solder. This paper describes the mechanics of the bonding action and verifies the effectiveness of this bonding method through wetting balance tests and scanning electron microscope and energy dispersive x-ray analysis. This technique has been demonstrated by using a gold stud bump to break the tin oxide layer over molten solder. This allows for a fast, solid liquid interdiffusion between gold (Au) and the fresh molten eutectic lead-tin (Pb-Sn) solder for joint formation during solidification. This bonding method has been successfully tested with 130-μm-pitch flip-chip bond pads on a joint-in-via flex substrate architecture

  5. A review on solder reflow and flux application for flip chip

    Science.gov (United States)

    Suppiah, Sarveshvaran; Ong, Nestor Rubio; Sauli, Zaliman; Sarukunaselan, Karunavani; Alcain, Jesselyn Barro; Visvanathan, Susthitha Menon; Retnasamy, Vithyacharan

    2017-09-01

    This paper encompassed of the evolution and key findings, critical technical challenges, solutions and bonding equipment of solder reflow in flip chip bonding. Upon scrutinizing researches done by others, it can be deduced that peak temperature, time above liquidus, soak temperature, soak time, cooling rate and reflow environment played a vital role in achieving the desired bonding profile. In addition, flux is also needed with the purpose of removing oxides/contaminations on bump surface as well as to promote wetting of solder balls. Electromigration and warpage are the two main challenges faced by solder reflow process which can be overcome by the advancement in under bump metallization (UBM) and substrate technology. The review is ended with a brief description of the current equipment used in solder reflow process.

  6. Oxidation and reduction kinetics of eutectic SnPb, InSn, and AuSn: a knowledge base for fluxless solder bonding applications

    DEFF Research Database (Denmark)

    Kuhmann, Jochen Friedrich; Preuss, A.; Adolphi, B.

    1998-01-01

    : (1) SnPb; (2) InSn; (3) AuSn. The studies of the oxidation kinetics show that the growth of the native oxide, which covers the solder surfaces from the start of all soldering operations is self-limiting. The rate of oxidation on the molten, metallic solder surfaces is significantly reduced...... and reduction kinetics, are applied to flip-chip (FC) bonding experiments in vacuum with and without the injection of H2. Wetting in vacuum is excellent but the self-alignment during flip-chip soldering is restricted. The desired, perfectly self-aligned FC-bonds have been only achieved, using evaporated...

  7. Tin-Silver Alloys for Flip-Chip Bonding Studied with a Rotating Cylinder Electrode

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Pedersen, E.H.; Bech-Nielsen, G.

    1999-01-01

    Electrodeposition of solder for flip-chip bonding is studied in the form of a pyrophosphate/iodide tin-silver alloy bath. The objective is to obtain a uniform alloy composition, with 3.8 At.% silver, over a larger area. This specific alloy will provide an eutectic solder melting at 221°C (or 10°C...... photoresist, have shown a stable and promising alternative to pure tin and tin-lead alloys for flip-chip bonding applications....

  8. Study of silicon chip soldering in high-power transistor housing

    Directory of Open Access Journals (Sweden)

    Vasily S. Anosov

    2017-09-01

    We experimentally assessed the effect of outer housing layer materials and back side chip metallization. For lead-silver soldering of silicon chips, the best housing is that with a nickel outer layer rather than with a gold-plated one, because the resultant thermal resistance is lower and the absence of gold makes the technology cheaper. We obtained a 0.6 K/W thermal resistance for a 24 mm2 chip area.

  9. A Novel Technique for the Connection of Ceramic and Titanium Implant Components Using Glass Solder Bonding

    Directory of Open Access Journals (Sweden)

    Enrico Mick

    2015-07-01

    Full Text Available Both titanium and ceramic materials provide specific advantages in dental implant technology. However, some problems, like hypersensitivity reactions, corrosion and mechanical failure, have been reported. Therefore, the combining of both materials to take advantage of their pros, while eliminating their respective cons, would be desirable. Hence, we introduced a new technique to bond titanium and ceramic materials by means of a silica-based glass ceramic solder. Cylindrical compound samples (Ø10 mm × 56 mm made of alumina toughened zirconia (ATZ, as well as titanium grade 5, were bonded by glass solder on their end faces. As a control, a two-component adhesive glue was utilized. The samples were investigated without further treatment, after 30 and 90 days of storage in distilled water at room temperature, and after aging. All samples were subjected to quasi-static four-point-bending tests. We found that the glass solder bonding provided significantly higher bending strength than adhesive glue bonding. In contrast to the glued samples, the bending strength of the soldered samples remained unaltered by the storage and aging treatments. Scanning electron microscopy (SEM and energy-dispersive X-ray (EDX analyses confirmed the presence of a stable solder-ceramic interface. Therefore, the glass solder technique represents a promising method for optimizing dental and orthopedic implant bondings.

  10. Wax-bonding 3D microfluidic chips

    KAUST Repository

    Gong, Xiuqing; Yi, Xin; Xiao, Kang; Li, Shunbo; Kodzius, Rimantas; Qin, Jianhua; Wen, Weijia

    2013-01-01

    We report a simple, low-cost and detachable microfluidic chip incorporating easily accessible paper, glass slides or other polymer films as the chip materials along with adhesive wax as the recycling bonding material. We use a laser to cut through the paper or film to form patterns and then sandwich the paper and film between glass sheets or polymer membranes . The hot-melt adhesive wax can realize bridge bonding between various materials, for example, paper, polymethylmethacrylate (PMMA) film, glass sheets, or metal plate. The bonding process is reversible and the wax is reusable through a melting and cooling process. With this process, a three-dimensional (3D) microfluidic chip is achievable by vacuating and venting the chip in a hot-water bath. To study the biocompatibility and applicability of the wax-based microfluidic chip, we tested the PCR compatibility with the chip materials first. Then we applied the wax-paper based microfluidic chip to HeLa cell electroporation (EP ). Subsequently, a prototype of a 5-layer 3D chip was fabricated by multilayer wax bonding. To check the sealing ability and the durability of the chip, green fluorescence protein (GFP) recombinant Escherichia coli (E. coli) bacteria were cultured, with which the chemotaxis of E. coli was studied in order to determine the influence of antibiotic ciprofloxacin concentration on the E. coli migration.

  11. Wax-bonding 3D microfluidic chips

    KAUST Repository

    Gong, Xiuqing

    2013-10-10

    We report a simple, low-cost and detachable microfluidic chip incorporating easily accessible paper, glass slides or other polymer films as the chip materials along with adhesive wax as the recycling bonding material. We use a laser to cut through the paper or film to form patterns and then sandwich the paper and film between glass sheets or polymer membranes . The hot-melt adhesive wax can realize bridge bonding between various materials, for example, paper, polymethylmethacrylate (PMMA) film, glass sheets, or metal plate. The bonding process is reversible and the wax is reusable through a melting and cooling process. With this process, a three-dimensional (3D) microfluidic chip is achievable by vacuating and venting the chip in a hot-water bath. To study the biocompatibility and applicability of the wax-based microfluidic chip, we tested the PCR compatibility with the chip materials first. Then we applied the wax-paper based microfluidic chip to HeLa cell electroporation (EP ). Subsequently, a prototype of a 5-layer 3D chip was fabricated by multilayer wax bonding. To check the sealing ability and the durability of the chip, green fluorescence protein (GFP) recombinant Escherichia coli (E. coli) bacteria were cultured, with which the chemotaxis of E. coli was studied in order to determine the influence of antibiotic ciprofloxacin concentration on the E. coli migration.

  12. Laser Soldering and Thermal Cycling Tests of Monolithic Silicon Pixel Chips

    CERN Document Server

    Strand, Frode Sneve

    2015-01-01

    An ALPIDE-1 monolithic silicon pixel sensor prototype has been laser soldered to a flex printed circuit using a novel interconnection technique using lasers. This technique is to be optimised to ensure stable, good quality connections between the sensor chips and the FPCs. To test the long-term stability of the connections, as well as study the effects on hit thresholds and noise in the sensor, it was thermally cycled in a climate chamber 1200 times. The soldered connections showed good qualities like even melting and good adhesion on pad/flex surfaces, and the chip remained in working condition for 1080 cycles. After this, a few connections failed, having cracks in the soldering tin, rendering the chip unusable. Threshold and noise characteristics seemed stable, except for the noise levels of sector 2 in the chip, for 1000 cycles in a temperature interval of "10^{\\circ}" and "50^{\\circ}" C. Still, further testing with wider temperature ranges and more cycles is needed to test the limitations of the chi...

  13. Solder bond requirement for large, built-up, high-performance conductors

    International Nuclear Information System (INIS)

    Willig, R.L.

    1981-01-01

    Some large built-up conductors fabricated for large superconducting magnets are designed to operate above the maximum recovery current. Because the stability of these conductors is sensitive to the quality of the solder bond joining the composite superconductor to the high-conductivity substrate, a minimum bond requirement is necessary. The present analysis finds that the superconductor is unstable and becomes abruptly resistive when there are temperature excursions into the current sharing region of a poorly bonded conductor. This abrupt transition, produces eddy current heating in the vicinity of the superconducting filaments and causes a sharp reduction in the minimum propagating zone (MPZ) energy. This sensitivity of the MPZ energy to the solder bond contact area is used to specify a minimum bond requirement. For the superconducting MHD magnet built for the Component Development Integration Facility (CDIF), the minimum bonded surface area is .68 cm/sup 2//cm which is 44% of the composite perimeter. 5 refs

  14. Contact of ZnSb thermoelectric material to metallic electrodes using S-Bond 400 solder alloy

    DEFF Research Database (Denmark)

    Malik, Safdar Abbas; Le, Thanh Hung; Van Nong, Ngo

    2018-01-01

    and metallic electrodes. In this paper, we investigate the joining of ZnSb to Ni and Ag electrodes using a commercial solder alloy S-Bond 400 and hot-pressing technique. Ti and Cr layers are also introduced as a diffusion barrier and microstructure at the interfaces is observed by scanning electron microscopy....... We found that S-bond 400 solder reacts with Ag and Ni electrodes to form different alloys at the interfaces. Cr layer was found to be broken after joining, resulting in a thicker reaction/diffusion layer at the interface, while Ti layer was preserved....

  15. Decapsulation Method for Flip Chips with Ceramics in Microelectronic Packaging

    Science.gov (United States)

    Shih, T. I.; Duh, J. G.

    2008-06-01

    The decapsulation of flip chips bonded to ceramic substrates is a challenging task in the packaging industry owing to the vulnerability of the chip surface during the process. In conventional methods, such as manual grinding and polishing, the solder bumps are easily damaged during the removal of underfill, and the thin chip may even be crushed due to mechanical stress. An efficient and reliable decapsulation method consisting of thermal and chemical processes was developed in this study. The surface quality of chips after solder removal is satisfactory for the existing solder rework procedure as well as for die-level failure analysis. The innovative processes included heat-sink and ceramic substrate removal, solder bump separation, and solder residue cleaning from the chip surface. In the last stage, particular temperatures were selected for the removal of eutectic Pb-Sn, high-lead, and lead-free solders considering their respective melting points.

  16. Thermal fatigue life evaluation of SnAgCu solder joints in a multi-chip power module

    Science.gov (United States)

    Barbagallo, C.; Malgioglio, G. L.; Petrone, G.; Cammarata, G.

    2017-05-01

    For power devices, the reliability of thermal fatigue induced by thermal cycling has been prioritized as an important concern. The main target of this work is to apply a numerical procedure to assess the fatigue life for lead-free solder joints, that represent, in general, the weakest part of the electronic modules. Starting from a real multi-chip power module, FE-based models were built-up by considering different conditions in model implementation in order to simulate, from one hand, the worst working condition for the module and, from another one, the module standing into a climatic test room performing thermal cycles. Simulations were carried-out both in steady and transient conditions in order to estimate the module thermal maps, the stress-strain distributions, the effective plastic strain distributions and finally to assess the number of cycles to failure of the constitutive solder layers.

  17. Thermal fatigue life evaluation of SnAgCu solder joints in a multi-chip power module

    International Nuclear Information System (INIS)

    Barbagallo, C; Petrone, G; Cammarata, G; Malgioglio, G L

    2017-01-01

    For power devices, the reliability of thermal fatigue induced by thermal cycling has been prioritized as an important concern. The main target of this work is to apply a numerical procedure to assess the fatigue life for lead-free solder joints, that represent, in general, the weakest part of the electronic modules. Starting from a real multi-chip power module, FE-based models were built-up by considering different conditions in model implementation in order to simulate, from one hand, the worst working condition for the module and, from another one, the module standing into a climatic test room performing thermal cycles. Simulations were carried-out both in steady and transient conditions in order to estimate the module thermal maps, the stress-strain distributions, the effective plastic strain distributions and finally to assess the number of cycles to failure of the constitutive solder layers. (paper)

  18. Effect of Preconditioning and Soldering on Failures of Chip Tantalum Capacitors

    Science.gov (United States)

    Teverovsky, Alexander A.

    2014-01-01

    Soldering of molded case tantalum capacitors can result in damage to Ta205 dielectric and first turn-on failures due to thermo-mechanical stresses caused by CTE mismatch between materials used in the capacitors. It is also known that presence of moisture might cause damage to plastic cases due to the pop-corning effect. However, there are only scarce literature data on the effect of moisture content on the probability of post-soldering electrical failures. In this work, that is based on a case history, different groups of similar types of CWR tantalum capacitors from two lots were prepared for soldering by bake, moisture saturation, and longterm storage at room conditions. Results of the testing showed that both factors: initial quality of the lot, and preconditioning affect the probability of failures. Baking before soldering was shown to be effective to prevent failures even in lots susceptible to pop-corning damage. Mechanism of failures is discussed and recommendations for pre-soldering bake are suggested based on analysis of moisture characteristics of materials used in the capacitors' design.

  19. Chip-package nano-structured copper and nickel interconnections with metallic and polymeric bonding interfaces

    Science.gov (United States)

    Aggarwal, Ankur

    With the semiconductor industry racing toward a historic transition, nano chips with less than 45 nm features demand I/Os in excess of 20,000 that support computing speed in terabits per second, with multi-core processors aggregately providing highest bandwidth at lowest power. On the other hand, emerging mixed signal systems are driving the need for 3D packaging with embedded active components and ultra-short interconnections. Decreasing I/O pitch together with low cost, high electrical performance and high reliability are the key technological challenges identified by the 2005 International Technology Roadmap for Semiconductors (ITRS). Being able to provide several fold increase in the chip-to-package vertical interconnect density is essential for garnering the true benefits of nanotechnology that will utilize nano-scale devices. Electrical interconnections are multi-functional materials that must also be able to withstand complex, sustained and cyclic thermo-mechanical loads. In addition, the materials must be environmentally-friendly, corrosion resistant, thermally stable over a long time, and resistant to electro-migration. A major challenge is also to develop economic processes that can be integrated into back end of the wafer foundry, i.e. with wafer level packaging. Device-to-system board interconnections are typically accomplished today with either wire bonding or solders. Both of these are incremental and run into either electrical or mechanical barriers as they are extended to higher density of interconnections. Downscaling traditional solder bump interconnect will not satisfy the thermo-mechanical reliability requirements at very fine pitches of the order of 30 microns and less. Alternate interconnection approaches such as compliant interconnects typically require lengthy connections and are therefore limited in terms of electrical properties, although expected to meet the mechanical requirements. A novel chip-package interconnection technology is

  20. Mechanism of Solder Joint Cracks in Anisotropic Conductive Films Bonding and Solutions: Delaying Hot-Bar Lift-Up Time and Adding Silica Fillers

    Directory of Open Access Journals (Sweden)

    Shuye Zhang

    2018-01-01

    Full Text Available Micron sizes solder metallurgical joints have been applied in a thin film application of anisotropic conductive film and benefited three general advantages, such as lower joint resistance, higher power handling capability, and reliability, when compared with pressure based contact of metal conductor balls. Recently, flex-on-board interconnection has become more and more popular for mobile electronic applications. However, crack formation of the solder joint crack was occurred at low temperature curable acrylic polymer resins after bonding processes. In this study, the mechanism of SnBi58 solder joint crack at low temperature curable acrylic adhesive was investigated. In addition, SnBi58 solder joint cracks can be significantly removed by increasing the storage modulus of adhesives instead of coefficient of thermal expansion. The first approach of reducing the amount of polymer rebound can be achieved by using an ultrasonic bonding method to maintain a bonding pressure on the SnBi58 solder joints cooling to room temperature. The second approach is to increase storage modulus of adhesives by adding silica filler into acrylic polymer resins to prevent the solder joint from cracking. Finally, excellent acrylic based SnBi58 solder joints reliability were obtained after 1000 cycles thermal cycling test.

  1. Numerical Analysis of Warpage Induced by Thermo-Compression Bonding Process of Cu Pillar Bump Flip Chip Package

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Oh Young; Jung, Hoon Sun; Lee, Jung Hoon; Choa, Sung-Hoon [Seoul Nat’l Univ. of Science and Technology, Seoul (Korea, Republic of)

    2017-06-15

    In flip chip technology, the conventional solder bump has been replaced with a copper (Cu) pillar bump owing to its higher input/output (I/O) density, finer pitch, and higher reliability. However, Cu pillar bump technology faces several issues, such as interconnect shorting and higher low-k stress due to stiffer Cu pillar structure when the conventional reflow process is used. Therefore, the thermal compression bonding (TCB) process has been adopted in the flip chip attachment process in order to reduce the package warpage and stress. In this study, we investigated the package warpage induced during the TCB process using a numerical analysis. The warpage of the TCB process was compared with that of the reflow process.

  2. Temperature-controlled laser-soldering system and its clinical application for bonding skin incisions

    Science.gov (United States)

    Simhon, David; Gabay, Ilan; Shpolyansky, Gregory; Vasilyev, Tamar; Nur, Israel; Meidler, Roberto; Hatoum, Ossama Abu; Katzir, Abraham; Hashmonai, Moshe; Kopelman, Doron

    2015-12-01

    Laser tissue soldering is a method of repairing incisions. It involves the application of a biological solder to the approximated edges of the incision and heating it with a laser beam. A pilot clinical study was carried out on 10 patients who underwent laparoscopic cholecystectomy. Of the four abdominal incisions in each patient, two were sutured and two were laser soldered. Cicatrization, esthetical appearance, degree of pain, and pruritus in the incisions were examined on postoperative days 1, 7, and 30. The soldered wounds were watertight and healed well, with no discharge from these wounds or infection. The total closure time was equal in both methods, but the net soldering time was much shorter than suturing. There was no difference between the two types of wound closure with respect to the pain and pruritus on a follow-up of one month. Esthetically, the soldered incisions were estimated as good as the sutured ones. The present study confirmed that temperature-controlled laser soldering of human skin incisions is clinically feasible, and the results obtained were at least equivalent to those of standard suturing.

  3. An analysis of the pull strength behaviors of fine-pitch, flip chip solder interconnections using a Au-Pt-Pd thick film conductor on Low-Temperature, Co-fired Ceramic (LTCC) substrates

    International Nuclear Information System (INIS)

    Uribe, Fernando R.; Kilgo, Alice C.; Grazier, John Mark; Vianco, Paul Thomas; Zender, Gary L.; Hlava, Paul Frank; Rejent, Jerome Andrew

    2008-01-01

    The assembly of the BDYE detector requires the attachment of sixteen silicon (Si) processor dice (eight on the top side; eight on the bottom side) onto a low-temperature, co-fired ceramic (LTCC) substrate using 63Sn-37Pb (wt.%, Sn-Pb) in a double-reflow soldering process (nitrogen). There are 132 solder joints per die. The bond pads were gold-platinum-palladium (71Au-26Pt-3Pd, wt.%) thick film layers fired onto the LTCC in a post-process sequence. The pull strength and failure modes provided the quality metrics for the Sn-Pb solder joints. Pull strengths were measured in both the as-fabricated condition and after exposure to thermal cycling (-55/125 C; 15 min hold times; 20 cycles). Extremely low pull strengths--referred to as the low pull strength phenomenon--were observed intermittently throughout the product build, resulting in added program costs, schedule delays, and a long-term reliability concern for the detector. There was no statistically significant correlation between the low pull strength phenomenon and (1) the LTCC 'sub-floor' lot; (2) grit blasting the LTCC surfaces prior to the post-process steps; (3) the post-process parameters; (4) the conductor pad height (thickness); (5) the dice soldering assembly sequence; or (5) the dice pull test sequence. Formation of an intermetallic compound (IMC)/LTCC interface caused by thick film consumption during either the soldering process or by solid-state IMC formation was not directly responsible for the low-strength phenomenon. Metallographic cross sections of solder joints from dice that exhibited the low pull strength behavior, revealed the presence of a reaction layer resulting from an interaction between Sn from the molten Sn-Pb and the glassy phase at the TKN/LTCC interface. The thick film porosity did not contribute, explicitly, to the occurrence of reaction layer. Rather, the process of printing the very thin conductor pads was too sensitive to minor thixotropic changes to ink, which resulted in

  4. An analysis of the pull strength behaviors of fine-pitch, flip chip solder interconnections using a Au-Pt-Pd thick film conductor on Low-Temperature, Co-fired Ceramic (LTCC) substrates.

    Energy Technology Data Exchange (ETDEWEB)

    Uribe, Fernando R.; Kilgo, Alice C.; Grazier, John Mark; Vianco, Paul Thomas; Zender, Gary L.; Hlava, Paul Frank; Rejent, Jerome Andrew

    2008-09-01

    The assembly of the BDYE detector requires the attachment of sixteen silicon (Si) processor dice (eight on the top side; eight on the bottom side) onto a low-temperature, co-fired ceramic (LTCC) substrate using 63Sn-37Pb (wt.%, Sn-Pb) in a double-reflow soldering process (nitrogen). There are 132 solder joints per die. The bond pads were gold-platinum-palladium (71Au-26Pt-3Pd, wt.%) thick film layers fired onto the LTCC in a post-process sequence. The pull strength and failure modes provided the quality metrics for the Sn-Pb solder joints. Pull strengths were measured in both the as-fabricated condition and after exposure to thermal cycling (-55/125 C; 15 min hold times; 20 cycles). Extremely low pull strengths--referred to as the low pull strength phenomenon--were observed intermittently throughout the product build, resulting in added program costs, schedule delays, and a long-term reliability concern for the detector. There was no statistically significant correlation between the low pull strength phenomenon and (1) the LTCC 'sub-floor' lot; (2) grit blasting the LTCC surfaces prior to the post-process steps; (3) the post-process parameters; (4) the conductor pad height (thickness); (5) the dice soldering assembly sequence; or (5) the dice pull test sequence. Formation of an intermetallic compound (IMC)/LTCC interface caused by thick film consumption during either the soldering process or by solid-state IMC formation was not directly responsible for the low-strength phenomenon. Metallographic cross sections of solder joints from dice that exhibited the low pull strength behavior, revealed the presence of a reaction layer resulting from an interaction between Sn from the molten Sn-Pb and the glassy phase at the TKN/LTCC interface. The thick film porosity did not contribute, explicitly, to the occurrence of reaction layer. Rather, the process of printing the very thin conductor pads was too sensitive to minor thixotropic changes to ink, which resulted in

  5. Soldering-induced Cu diffusion and intermetallic compound formation between Ni/Cu under bump metallization and SnPb flip-chip solder bumps

    Science.gov (United States)

    Huang, Chien-Sheng; Jang, Guh-Yaw; Duh, Jenq-Gong

    2004-04-01

    Nickel-based under bump metallization (UBM) has been widely used as a diffusion barrier to prevent the rapid reaction between the Cu conductor and Sn-based solders. In this study, joints with and without solder after heat treatments were employed to evaluate the diffusion behavior of Cu in the 63Sn-37Pb/Ni/Cu/Ti/Si3N4/Si multilayer structure. The atomic flux of Cu diffused through Ni was evaluated from the concentration profiles of Cu in solder joints. During reflow, the atomic flux of Cu was on the order of 1015-1016 atoms/cm2s. However, in the assembly without solder, no Cu was detected on the surface of Ni even after ten cycles of reflow. The diffusion behavior of Cu during heat treatments was studied, and the soldering-process-induced Cu diffusion through Ni metallization was characterized. In addition, the effect of Cu content in the solder near the solder/intermetallic compound (IMC) interface on interfacial reactions between the solder and the Ni/Cu UBM was also discussed. It is evident that the (Cu,Ni)6Sn5 IMC might form as the concentration of Cu in the Sn-Cu-Ni alloy exceeds 0.6 wt.%.

  6. Size effects in tin-based lead-free solder joints: Kinetics of bond formation and mechanical characteristics

    Science.gov (United States)

    Abdelhadi, Ousama Mohamed Omer

    Continuous miniaturization of microelectronic interconnects demands smaller joints with comparable microstructural and structural sizes. As the size of joints become smaller, the volume of intermetallics (IMCs) becomes comparable with the joint size. As a result, the kinetics of bond formation changes and the types and thicknesses of IMC phases that form within the constrained region of the bond varies. This dissertation focuses on investigating combination effects of process parameters and size on kinetics of bond formation, resulting microstructure and the mechanical properties of joints that are formed under structurally constrained conditions. An experiment is designed where several process parameters such as time of bonding, temperature, and pressure, and bond thickness as structural chracteristic, are varied at multiple levels. The experiment is then implemented on the process. Scanning electron microscope (SEM) is then utilized to determine the bond thickness, IMC phases and their thicknesses, and morphology of the bonds. Electron backscatter diffraction (EBSD) is used to determine the grain size in different regions, including the bulk solder, and different IMC phases. Physics-based analytical models have been developed for growth kinetics of IMC compounds and are verified using the experimental results. Nanoindentation is used to determine the mechanical behavior of IMC phases in joints in different scales. Four-point bending notched multilayer specimen and four-point bending technique were used to determine fracture toughness of the bonds containing IMCs. Analytical modeling of peeling and shear stresses and fracture toughness in tri-layer four-point bend specimen containing intermetallic layer was developed and was verified and validated using finite element simulation and experimental results. The experiment is used in conjunction with the model to calculate and verify the fracture toughness of Cu6Sn5 IMC materials. As expected two different IMC phases

  7. Rework of flip chip bonded radiation pixel detectors

    International Nuclear Information System (INIS)

    Vaehaenen, S.; Heikkinen, H.; Pohjonen, H.; Salonen, J.; Savolainen-Pulli, S.

    2008-01-01

    In this paper, some practical aspects of reworking flip chip hybridized pixel detectors are discussed. As flip chip technology has been advancing in terms of placement accuracy and reliability, large-area hybrid pixel detectors have been developed. The area requirements are usually fulfilled by placing several readout chips (ROCs) on single sensor chip. However, as the number of ROCs increases, the probability of failure in the hybridization process and the ROC operation also increases. Because high accuracy flip chip bonding takes time, a significant part of the price of a pixel detector comes from the flip chip assembly process itself. As large-area detector substrates are expensive, and many flip chip placements are required, the price of an assembled detector can become very high. In a typical case, there is just one bad ROC (out of several) on a faulty detector to be replaced. Considering the high price of pixel detectors and the fact that reworking faulty ROCs does not take much longer than the original placement, it is worthwhile to investigate the feasibility of a rework process

  8. Rework of flip chip bonded radiation pixel detectors

    Energy Technology Data Exchange (ETDEWEB)

    Vaehaenen, S. [VTT MEMS and Micropackaging, Espoo 02150 (Finland)], E-mail: sami.vahanen@vtt.fi; Heikkinen, H.; Pohjonen, H.; Salonen, J.; Savolainen-Pulli, S. [VTT MEMS and Micropackaging, Espoo 02150 (Finland)

    2008-06-11

    In this paper, some practical aspects of reworking flip chip hybridized pixel detectors are discussed. As flip chip technology has been advancing in terms of placement accuracy and reliability, large-area hybrid pixel detectors have been developed. The area requirements are usually fulfilled by placing several readout chips (ROCs) on single sensor chip. However, as the number of ROCs increases, the probability of failure in the hybridization process and the ROC operation also increases. Because high accuracy flip chip bonding takes time, a significant part of the price of a pixel detector comes from the flip chip assembly process itself. As large-area detector substrates are expensive, and many flip chip placements are required, the price of an assembled detector can become very high. In a typical case, there is just one bad ROC (out of several) on a faulty detector to be replaced. Considering the high price of pixel detectors and the fact that reworking faulty ROCs does not take much longer than the original placement, it is worthwhile to investigate the feasibility of a rework process.

  9. A novel bonding method for fabrication of PET planar nanofluidic chip with low dimension loss and high bonding strength

    International Nuclear Information System (INIS)

    Yin, Zhifu; Zou, Helin; Sun, Lei; Xu, Shenbo; Qi, Liping

    2015-01-01

    Plastic planar nanofluidic chips are becoming increasingly important for biological and chemical applications. However, the majority of the present bonding methods for planar nanofluidic chips suffer from high dimension loss and low bonding strength. In this work, a novel thermal bonding technique based on O 2 plasma and ethanol treatment was proposed. With the assistance of O 2 plasma and ethanol, the PET (polyethylene terephthalate) planar nanofluidic chip can be bonded at a low bonding temperature of 50 °C. To increase the bonding rate and bonding strength, the O 2 plasma parameters and thermal bonding parameters were optimized during the bonding process. The tensile test indicates that the bonding strength of the PET planar nanofluidic chip can reach 0.954 MPa, while the auto-fluorescence test demonstrates that there is no leakage or blockage in any of the bonded micro- or nanochannels. (paper)

  10. Fluxless Bonding Processes Using Silver-Indium System for High Temperature Electronics and Silver Flip-Chip Interconnect Technology

    Science.gov (United States)

    Wu, Yuan-Yun

    In this dissertation, fluxless silver (Ag)-indium (In) binary system bonding and Ag solid-state bonding are used between different bonded pairs which have large thermal expansion coefficient (CTE) mismatch and flip-chip interconnect bonding application. In contrast to the conventional soldering process, fluxless bonding technique eliminates contamination and reliability problems caused by flux to fabricate high quality joints. There are two section are reported. In the first section, the reactions of Ag-In binary system are presented. In the second section, the high melting temperature, thermal and electrical conductivity joint materials bonding by either Ag-In binary system bonding or solid-state bonding processes for different bonded pairs and flip-chip application are designed, developed, and reported. Our group have studied Ag-In system for several years and developed the bonding processes successfully. However, the detailed reactions of Ag and In were seldom studied. To design a proper bonding structure, it is necessary to understand the reaction between Ag and In. The systematic experiments were performed to investigate these reactions. A 40 um Ag layer was electroplated on copper (Cu) substrates, followed by indium layers of 1, 3, 5, 10, and 15 um, respectively. The samples were annealed at 180 °C in 0.1 torr vacuum. For samples with In thickness less than 5 mum, the joint compositions are Ag2In only (1 um) or AgIn2, Ag2In, and Ag solid solution (Ag) after annealing. No indium is identified. For 10 and 15 um thick In samples, In covers almost over the entire sample surface after annealing. Later, an Ag layer was annealed at 450 °C for 3 hours to grow Ag grains, followed by plating 10 um In and annealing at 180 °C. By annealing Ag before plating In, more In is kept in the structure during annealing at 180 °C. Based on above results, for those designs with In thinner than 5 um, the Ag layer needs to be annealed, prior to In plating in order to make a

  11. Non-contact estimation of the bond quality in soldered thin laminate by laser generated lamb waves; Laser reiki ramuha ni yoru handazuke sekisohaku no setsugo seijo no hisesshoku hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Kasama, H.; Futatsugi, T.; Cho, H.; Takemoto, M. [Aoyama-Gakuin University, Tokyo (Japan). Faculty of Science and Engineering

    1998-03-20

    The bond quality of a solder-bonded copper laminated plate was modeled into rigid contact (rc) and slip contact (sc) to calculate the velocity dispersion of lamb waves. The velocity dispersion of laser generated lamb waves was measured, and the bond quality or the thickness of a solder layer was evaluated by non-contact. In the model whose bond surface is rc, the velocity dispersion of lamb waves can be calculated under conditions where the stress and displacement in an interface are continuous. In the model whose bond surface is sc, it can be calculated under conditions where an interface slips freely. Weak bond indicates the velocity dispersion between rc and sc. In this model, the velocity dispersion can also be calculated by a change in the thickness of a solder layer and used for quantitative evaluation of a bond interface. A three-layer solder bond manufactured for trial could be evaluated from the velocity dispersion of laser lamb waves. At the room temperature, the change in bond quality near the solder melting point of bond laminate that was judged as rc was investigated. When the solidus temperature is exceeded, the amplitude of lamb waves and the velocity dispersion changed largely. The amplitude of lamb waves increases as the liquid phase ratio increases. The bond quality near the solder melting point can be evaluated using lamb waves. 9 refs., 10 figs., 2 tabs.

  12. Soldering handbook

    CERN Document Server

    Vianco, Paul T

    1999-01-01

    Contains information related to soldering processes, and solder joint performance and reliability. Covers soldering fundamentals, technology, materials, substrate materials, fluxes, pastes, assembly processes, inspection, and environment. Covers today's advanced joining applications and emphasizes new materials, including higher strength alloys; predictive performance; computer modeling; advanced inspection techniques; new processing concepts, including laser heating; and the resurgence in ultrasonic soldering.

  13. Thermomechanical Behavior of Monolithic SN-AG-CU Solder and Copper Fiber Reinforced Solders

    National Research Council Canada - National Science Library

    Reuse, Rolando

    2005-01-01

    .... The thermomechanical cycling in the solder causes numerous reliability challenges, mostly because of the mismatch of the coefficient of thermal expansion between the silicon chip and the substrate...

  14. A novel bonding method for large scale poly(methyl methacrylate) micro- and nanofluidic chip fabrication

    Science.gov (United States)

    Qu, Xingtian; Li, Jinlai; Yin, Zhifu

    2018-04-01

    Micro- and nanofluidic chips are becoming increasing significance for biological and medical applications. Future advances in micro- and nanofluidics and its utilization in commercial applications depend on the development and fabrication of low cost and high fidelity large scale plastic micro- and nanofluidic chips. However, the majority of the present fabrication methods suffer from a low bonding rate of the chip during thermal bonding process due to air trapping between the substrate and the cover plate. In the present work, a novel bonding technique based on Ar plasma and water treatment was proposed to fully bond the large scale micro- and nanofluidic chips. The influence of Ar plasma parameters on the water contact angle and the effect of bonding conditions on the bonding rate and the bonding strength of the chip were studied. The fluorescence tests demonstrate that the 5 × 5 cm2 poly(methyl methacrylate) chip with 180 nm wide and 180 nm deep nanochannels can be fabricated without any block and leakage by our newly developed method.

  15. Chip bonding of low-melting eutectic alloys by transmitted laser radiation

    Science.gov (United States)

    Hoff, Christian; Venkatesh, Arjun; Schneider, Friedrich; Hermsdorf, Jörg; Bengsch, Sebastian; Wurz, Marc C.; Kaierle, Stefan; Overmeyer, Ludger

    2017-06-01

    Present-day thermode bond systems for the assembly of radio-frequency identification (RFID) chips are mechanically inflexible, difficult to control, and will not meet future manufacturing challenges sufficiently. Chip bonding, one of the key processes in the production of integrated circuits (ICs), has a high potential for optimization with respect to process duration and process flexibility. For this purpose, the technologies used, so far, are supposed to be replaced by a transmission laser-bonding process using low-melting eutectic alloys. In this study, successful bonding investigations of mock silicon chips and of RFID chips on flexible polymer substrates are presented using the low-melting eutectic alloy, 52In48Sn, and a laser with a wavelength of 2 μm.

  16. Flip-chip bonded optoelectronic integration based on ultrathin silicon (UTSi) CMOS

    Science.gov (United States)

    Hong, Sunkwang; Ho, Tawei; Zhang, Liping; Sawchuk, Alexander A.

    2003-06-01

    We describe the design and test of flip-chip bonded optoelectronic CMOS devices based on Peregrine Semiconductor's 0.5 micron Ultra-Thin Silicon on sapphire (UTSi) technology. The UTSi process eliminates the substrate leakage that typically results in crosstalk and reduces parasitic capacitance to the substrate, providing many benefits compared to bulk silicon CMOS. The low-loss synthetic sapphire substrate is optically transparent and has a coefficient of thermal expansion suitable for flip-chip bonding of vertical cavity surface emitting lasers (VCSELs) and detectors. We have designed two different UTSi CMOS chips. One contains a flip-chip bonded 1 x 4 photodiode array, a receiver array, a double edge triggered D-flip flop-based 2047-pattern pseudo random bit stream (PRBS) generator and a quadrature-phase LC-voltage controlled oscillator (VCO). The other chip contains a flip-chip bonded 1 x 4 VCSEL array, a driver array based on high-speed low-voltage differential signals (LVDS) and a full-balanced differential LC-VCO. Each VCSEL driver and receiver has individual input and bias voltage adjustments. Each UTSi chip is mounted on different printed circuit boards (PCBs) which have holes with about 1 mm radius for optical output and input paths through the sapphire substrate. We discuss preliminary testing of these chips.

  17. Soldering of Nanotubes onto Microelectrodes

    DEFF Research Database (Denmark)

    Madsen, Dorte Nørgaard; Mølhave, Kristian; Mateiu, Ramona Valentina

    2003-01-01

    Suspended bridges of individual multiwalled carbon nanotubes were fabricated inside a scanning electron microscope by soldering the nanotube onto microelectrodes with highly conducting gold-carbon material. By the decomposition of organometallic vapor with the electron beam, metal-containing sold...... bonds were consistently found to be mechanically stronger than the carbon nanotubes.......Suspended bridges of individual multiwalled carbon nanotubes were fabricated inside a scanning electron microscope by soldering the nanotube onto microelectrodes with highly conducting gold-carbon material. By the decomposition of organometallic vapor with the electron beam, metal-containing solder...... bonds were formed at the intersection of the nanotube and the electrodes. Current-voltage curves indicated metallic conduction of the nanotubes, with resistances in the range of 9-29 kOmega. Bridges made entirely of the soldering material exhibited resistances on the order of 100 Omega, and the solder...

  18. Ultrasonic welding for fast bonding of self-aligned structures in lab-on-a-chip systems

    DEFF Research Database (Denmark)

    Kistrup, Kasper; Poulsen, Carl Esben; Hansen, Mikkel Fougt

    2015-01-01

    Ultrasonic welding is a rapid, promising bonding method for the bonding of polymer chips; yet its use is still limited. We present two lab-on-a-chip applications where ultrasonic welding can be preferably applied: (1) Self-aligned gapless bonding of a two-part chip with a tolerance of 50 um; (2...... solutions offered here can significantly help bridge the gap between academia and industry, where the differences in production methods and materials pose a challenge when transferring technology....

  19. Characterization of Ni/SnPb-TiW/Pt Flip Chip Interconnections in Silicon Pixel Detector Modules

    CERN Document Server

    Karadzhinova, Aneliya; Härkönen, Jaakko; Luukka, Panja-riina; Mäenpää, Teppo; Tuominen, Eija; Haeggstrom, Edward; Kalliopuska, Juha; Vahanen, Sami; Kassamakov, Ivan

    2014-01-01

    In contemporary high energy physics experiments, silicon detectors are essential for recording the trajectory of new particles generated by multiple simultaneous collisions. Modern particle tracking systems may feature 100 million channels, or pixels, which need to be individually connected to read-out chains. Silicon pixel detectors are typically connected to readout chips by flip-chip bonding using solder bumps. High-quality electro-mechanical flip-chip interconnects minimizes the number of dead read-out channels in the particle tracking system. Furthermore, the detector modules must endure handling during installation and withstand heat generation and cooling during operation. Silicon pixel detector modules were constructed by flip-chip bonding 16 readout chips to a single sensor. Eutectic SnPb solder bumps were deposited on the readout chips and the sensor chips were coated with TiW/Pt thin film UBM (under bump metallization). The modules were assembled at Advacam Ltd, Finland. We studied the uniformity o...

  20. High power vertical stacked and horizontal arrayed diode laser bar development based on insulation micro-channel cooling (IMCC) and hard solder bonding technology

    Science.gov (United States)

    Wang, Boxue; Jia, Yangtao; Zhang, Haoyu; Jia, Shiyin; Liu, Jindou; Wang, Weifeng; Liu, Xingsheng

    2018-02-01

    An insulation micro-channel cooling (IMCC) has been developed for packaging high power bar-based vertical stack and horizontal array diode lasers, which eliminates many issues caused in its congener packaged by commercial copper formed micro-channel cooler(MCC), such as coefficient of thermal expansion (CTE) mismatch between cooler and diode laser bar, high coolant quality requirement (DI water) and channel corrosion and electro-corrosion induced by DI water if the DI-water quality is not well maintained The IMCC cooler separates water flow route and electrical route, which allows tap-water as coolant without electro-corrosion and therefore prolongs cooler lifetime dramatically and escalated the reliability of these diode lasers. The thickness of ceramic and copper in an IMCC cooler is well designed to minimize the CTE mismatch between laser bar and cooler, consequently, a very low "SMILE" of the laser bar can be achieved for small fast axis divergence after collimation. In additional, gold-tin hard solder bonding technology was also developed to minimize the risk of solder electromigration at high current density and thermal fatigue under hard-pulse operation mode. Testing results of IMCC packaged diode lasers are presented in this report.

  1. Laser soldering of Sn-Ag-Cu and Sn-Zn-Bi lead-free solder pastes

    Science.gov (United States)

    Takahashi, Junichi; Nakahara, Sumio; Hisada, Shigeyoshi; Fujita, Takeyoshi

    2004-10-01

    It has reported that a waste of an electronics substrate including lead and its compound such as 63Sn-37Pb has polluted the environment with acid rain. For that environment problem the development of lead-free solder alloys has been promoted in order to find out the substitute for Sn-Pb solders in the United States, Europe, and Japan. In a present electronics industry, typical alloys have narrowed down to Sn-Ag-Cu and Sn-Zn lead-free solder. In this study, solderability of Pb-free solder that are Sn-Ag-Cu and Sn-Zn-Bi alloy was studied on soldering using YAG (yttrium aluminum garnet) laser and diode laser. Experiments were peformed in order to determine the range of soldering parameters for obtaining an appropriate wettability based on a visual inspection. Joining strength of surface mounting chip components soldered on PCB (printed circuit board) was tested on application thickness of solder paste (0.2, 0.3, and 0.4 mm). In addition, joining strength characteristics of eutectic Sn-Pb alloy and under different power density were examined. As a result, solderability of Sn-Ag-Cu (Pb-free) solder paste are equivalent to that of coventional Sn-Pb solder paste, and are superior to that of Sn-Zn-Bi solder paste in the laser soldering method.

  2. Efforts to Develop a 300°C Solder

    Energy Technology Data Exchange (ETDEWEB)

    Norann, Randy A [Perma Works LLC

    2015-01-25

    This paper covers the efforts made to find a 300°C electrical solder solution for geothermal well monitoring and logging tools by Perma Works LLC. This paper covers: why a high temperature solder is needed, what makes for a good solder, testing flux, testing conductive epoxy and testing intermetallic bonds. Future areas of research are suggested.

  3. Lead free solder mechanics and reliability

    CERN Document Server

    Pang, John Hock Lye

    2012-01-01

    Lead-free solders are used extensively as interconnection materials in electronic assemblies and play a critical role in the global semiconductor packaging and electronics manufacturing industry. Electronic products such as smart phones, notebooks and high performance computers rely on lead-free solder joints to connect IC chip components to printed circuit boards. Lead Free Solder: Mechanics and Reliability provides in-depth design knowledge on lead-free solder elastic-plastic-creep and strain-rate dependent deformation behavior and its application in failure assessment of solder joint reliability. It includes coverage of advanced mechanics of materials theory and experiments, mechanical properties of solder and solder joint specimens, constitutive models for solder deformation behavior; numerical modeling and simulation of solder joint failure subject to thermal cycling, mechanical bending fatigue, vibration fatigue and board-level drop impact tests. This book also: Discusses the mechanical prope...

  4. Spontaneous soldering

    International Nuclear Information System (INIS)

    Percacci, R.

    1984-01-01

    It is proposed that the soldering form of general relativity be treated as a dynamical variable. This gives rise to the possibility of treating the linear connection on (n-dimensional) spacetime and an internal O(k)-Yang-Mills field as different components of the same O(N) gauge field (N= n+k). The distinction between gravitational and Yang-Mills interactions is due to a kind of Higgs mechanism driven by the vacuum expectation value of the soldering form. (orig.)

  5. Soldering in electronics assembly

    CERN Document Server

    Judd, Mike

    2013-01-01

    Soldering in Electronics Assembly discusses several concerns in soldering of electronic assemblies. The book is comprised of nine chapters that tackle different areas in electronic assembly soldering. Chapter 1 discusses the soldering process itself, while Chapter 2 covers the electronic assemblies. Chapter 3 talks about solders and Chapter 4 deals with flux. The text also tackles the CS and SC soldering process. The cleaning of soldered assemblies, solder quality, and standards and specifications are also discussed. The book will be of great use to professionals who deal with electronic assem

  6. Thin film metal sensors in fusion bonded glass chips for high-pressure microfluidics

    International Nuclear Information System (INIS)

    Andersson, Martin; Ek, Johan; Hedman, Ludvig; Johansson, Fredrik; Sehlstedt, Viktor; Stocklassa, Jesper; Snögren, Pär; Pettersson, Victor; Larsson, Jonas; Vizuete, Olivier; Hjort, Klas; Klintberg, Lena

    2017-01-01

    High-pressure microfluidics offers fast analyses of thermodynamic parameters for compressed process solvents. However, microfluidic platforms handling highly compressible supercritical CO 2 are difficult to control, and on-chip sensing would offer added control of the devices. Therefore, there is a need to integrate sensors into highly pressure tolerant glass chips. In this paper, thin film Pt sensors were embedded in shallow etched trenches in a glass wafer that was bonded with another glass wafer having microfluidic channels. The devices having sensors integrated into the flow channels sustained pressures up to 220 bar, typical for the operation of supercritical CO 2 . No leakage from the devices could be found. Integrated temperature sensors were capable of measuring local decompression cooling effects and integrated calorimetric sensors measured flow velocities over the range 0.5–13.8 mm s −1 . By this, a better control of high-pressure microfluidic platforms has been achieved. (paper)

  7. Investigation of Sn-Pb solder bumps of prototype photo detectors for the LHCb experiment

    CERN Document Server

    Delsante, M L; Arnau-Izquierdo, G

    2004-01-01

    The Large Hadron Collider (LHC) is now under construction at the European Organization for Nuclear Research (CERN). LHCb is one of the dedicated LHC experiments, allowing high energy proton-proton collisions to be exploited. This paper presents the results of the metallurgic studies carried out on Sn-Pb solder bumps of prototype vacuum photo detectors under development for LHCb, and in particular for the ring imaging Cherenkov-hybrid photo diode (RICH-HPD) project. These detectors encapsulate, in a vacuum tube, an assembly made of two silicon chips bonded together by a matrix of solder bumps. Each bump lies on a suitable system of under-bump metallic layers ensuring mechanical and electrical transition between the chip pad and the solder alloy. During manufacturing of the detector, bump-bonded (BB) assemblies are exposed to severe heat cycles up to 400 degree C inducing, in the present fabrication process, a clear degradation of electrical connectivity. Several investigations such as microstructural observati...

  8. A Corrosion Investigation of Solder Candidates for High-Temperature Applications

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hald, John; Ambat, Rajan

    2009-01-01

    The step soldering approach is being employed in the Multi-Chip module (MCM) technology. High lead containing alloys is one of the solders currently being used in this approach. Au-Sn and Au-Ge based candidate alloys have been proposed as alternative solders for this application. In this work...

  9. PMMA to SU-8 bonding for polymer based lab-on-a-chip systems with integrated optics

    DEFF Research Database (Denmark)

    Olsen, Brian Bilenberg; Nielsen, Theodor; Clausen, Bjarne Hans

    2004-01-01

    We present an adhesive bonding technique developed for SU-8 based "lab-on-a-chip"- systems with integrated optical components. Microfluidic channels and optical components (e.g. wave-guides) are defined in SU-8 photoresist on a Pyrex glass substrate. The microfluidic channels are sealed by a second...... Pyrex substrate, bonded on top of the cross-linked SU-8 structure using an inter- mediate layer of 950K molecular weight poly-methylmethacrylate (PMMA). Due to a lower refractive index of PMMA, this bonding technique offers optical waveguiding in the SU-8 structures in combination with good sealing...... of the microfluidic channels. The bonding technique is investigated with respect to bonding temperature in the range of 50 - 150 degr. C and at bonding forces of 1000 N and 2000 N on a 4-inch wafer. A maximum bonding strength of 16 MPa is achieved for the PMMA to SU-8 bonding at a bonding temperature of 110 degr. C...

  10. Photothermal effects of laser tissue soldering

    International Nuclear Information System (INIS)

    McNally, K.M.; Sorg, B.S.; Welch, A.J.; Dawes, J.M.; Owen, E.R.

    1999-01-01

    Low-strength anastomoses and thermal damage of tissue are major concerns in laser tissue welding techniques where laser energy is used to induce thermal changes in the molecular structure of the tissues being joined, hence allowing them to bond together. Laser tissue soldering, on the other hand, is a bonding technique in which a protein solder is applied to the tissue surfaces to be joined, and laser energy is used to bond the solder to the tissue surfaces. The addition of protein solders to augment tissue repair procedures significantly reduces the problems of low strength and thermal damage associated with laser tissue welding techniques. Investigations were conducted to determine optimal solder and laser parameters for tissue repair in terms of tensile strength, temperature rise and damage and the microscopic nature of the bonds formed. An in vitro study was performed using an 808 nm diode laser in conjunction with indocyanine green (ICG)-doped albumin protein solders to repair bovine aorta specimens. Liquid and solid protein solders prepared from 25% and 60% bovine serum albumin (BSA), respectively, were compared. The efficacy of temperature feedback control in enhancing the soldering process was also investigated. Increasing the BSA concentration from 25% to 60% greatly increased the tensile strength of the repairs. A reduction in dye concentration from 2.5mgml -1 to 0.25mgml -1 was also found to result in an increase in tensile strength. Increasing the laser irradiance and thus surface temperature resulted in an increased severity of histological injury. Thermal denaturation of tissue collagen and necrosis of the intimal layer smooth muscle cells increased laterally and in depth with higher temperatures. The strongest repairs were produced with an irradiance of 6.4Wcm -2 using a solid protein solder composed of 60% BSA and 0.25mgml -1 ICG. Using this combination of laser and solder parameters, surface temperatures were observed to reach 85±5 deg. C with a

  11. SMT soldering handbook

    National Research Council Canada - National Science Library

    Strauss, Rudolf

    1998-01-01

    ... 3.2.1 Constituents, melting behaviour and mechanical properties 3.2.2 Composition of solders for use in electronics 3.2.3 Lead-free solders 3.2.4 Solder impurities The soldered joint 3.3.1 Solde...

  12. Flexure mechanism-based parallelism measurements for chip-on-glass bonding

    International Nuclear Information System (INIS)

    Jung, Seung Won; Yun, Won Soo; Jin, Songwan; Jeong, Young Hun; Kim, Bo Sun

    2011-01-01

    Recently, liquid crystal displays (LCDs) have played vital roles in a variety of electronic devices such as televisions, cellular phones, and desktop/laptop monitors because of their enhanced volume, performance, and functionality. However, there is still a need for thinner LCD panels due to the trend of miniaturization in electronic applications. Thus, chip-on-glass (COG) bonding has become one of the most important aspects in the LCD panel manufacturing process. In this study, a novel sensor was developed to measure the parallelism between the tooltip planes of the bonding head and the backup of the COG main bonder, which has previously been estimated by prescale pressure films in industry. The sensor developed in this study is based on a flexure mechanism, and it can measure the total pressing force and the inclination angles in two directions that satisfy the quantitative definition of parallelism. To improve the measurement accuracy, the sensor was calibrated based on the estimation of the total pressing force and the inclination angles using the least-squares method. To verify the accuracy of the sensor, the estimation results for parallelism were compared with those from prescale pressure film measurements. In addition, the influence of parallelism on the bonding quality was experimentally demonstrated. The sensor was successfully applied to the measurement of parallelism in the COG-bonding process with an accuracy of more than three times that of the conventional method using prescale pressure films

  13. PMMA to SU-8 Bonding for Polymer Based Lab-on-a-chip Systems with Integrated Optics

    DEFF Research Database (Denmark)

    Olsen, Brian Bilenberg; Nielsen, Theodor; Nilsson, Daniel

    2003-01-01

    An adhesive bonding technique for wafer-level sealing of SU-8 based lab-on-a-chip microsystems with integrated optical components is presented. Microfluidic channels and optical components, e.g. waveguides, are fabricated in cross-linked SU-8 and sealed with a Pyrex glass substrate by means...... strength of 16 MPa is achieved at bonding temperatures between 110 oC and 120oC, at a bonding force of 2000 N on a 4-inch wafer. The optical propagation loss of multi-mode 10ym (thickness)x 30ym (width)SU-8 waveguides is measured. The propagation loss in PMMA bonded waveguide struc-tures is more than 5 d......B/cm lower, at wavelengths between 600nm and 900 nm, than in similar structures bonded by an intermediate layer of SU-8. Furthermore 950K PMMA shows no tendency to flow into the bonded structures during bonding because of its high viscosity....

  14. Comparison of Ultrasonic Welding and Thermal Bonding for the Integration of Thin Film Metal Electrodes in Injection Molded Polymeric Lab-on-Chip Systems for Electrochemistry

    DEFF Research Database (Denmark)

    Matteucci, Marco; Heiskanen, Arto; Zor, Kinga

    2016-01-01

    We compare ultrasonic welding (UW) and thermal bonding (TB) for the integration of embedded thin-film gold electrodes for electrochemical applications in injection molded (IM) microfluidic chips. The UW bonded chips showed a significantly superior electrochemical performance compared to the ones ...

  15. Optimal parameters for laser tissue soldering

    Science.gov (United States)

    McNally-Heintzelman, Karen M.; Sorg, Brian S.; Chan, Eric K.; Welch, Ashley J.; Dawes, Judith M.; Owen, Earl R.

    1998-07-01

    Variations in laser irradiance, exposure time, solder composition, chromophore type and concentration have led to inconsistencies in published results of laser-solder repair of tissue. To determine optimal parameters for laser tissue soldering, an in vitro study was performed using an 808-nm diode laser in conjunction with an indocyanine green (ICG)- doped albumin protein solder to weld bovine aorta specimens. Liquid and solid protein solders prepared from 25% and 60% bovine serum albumin (BSA), respectively, were compared. The effects of laser irradiance and exposure time on tensile strength of the weld and temperature rise as well as the effect of hydration on bond stability were investigated. Optimum irradiance and exposure times were identified for each solder type. Increasing the BSA concentration from 25% to 60% greatly increased the tensile strength of the weld. A reduction in dye concentration from 2.5 mg/ml to 0.25 mg/ml was also found to result in an increase in tensile strength. The strongest welds were produced with an irradiance of 6.4 W/cm2 for 50 s using a solid protein solder composed of 60% BSA and 0.25 mg/ml ICG. Steady-state solder surface temperatures were observed to reach 85 plus or minus 5 degrees Celsius with a temperature gradient across the solid protein solder strips of between 15 and 20 degrees Celsius. Finally, tensile strength was observed to decrease significantly (20 to 25%) after the first hour of hydration in phosphate-buffered saline. No appreciable change was observed in the strength of the tissue bonds with further hydration.

  16. Development of new assembly techniques for a silicon micro-vertex detector unit using the flip-chip bonding method

    International Nuclear Information System (INIS)

    Saitoh, Y.; Takeuchi, H.; Mandai, M.; Kanazawa, H.; Yamanaka, J.; Miyahara, S.; Kamiya, M.; Fujita, Y.; Higashi, Y.; Ikeda, H.; Ikeda, M.; Koike, S.; Matsuda, T.; Ozaki, H.; Tanaka, M.; Tsuboyama, T.; Avrillon, S.; Okuno, S.; Haba, J.; Hanai, H.; Mori, S.; Yusa, K.; Fukunaga, C.

    1994-01-01

    Full-size models of a detector unit for a silicon micro-vertex detector were built for the KEK B factory. The Flip-Chip Bonding (FCB) method using a new type anisotropic conductive film was examined. The structure using the FCB method successfully provides a new architecture for the silicon micro-vertex detector unit. (orig.)

  17. Analysis of a flip-chip bonded tunable high-temperature superconducting coplanar waveguide resonator using the conformal mapping technique

    CERN Document Server

    Misra, M; Murakami, H; Tonouchi, M

    2003-01-01

    We have studied the tuning properties of a high-temperature superconducting (HTS) half-wavelength coplanar waveguide (CPW) resonator operating at 5 GHz. The tuning schemes are based on flip-chip bonding of an electrically tunable ferroelectric (FE) thin film and a mechanically movable low-loss single crystal on top of the resonator. Using the conformal mapping method, closed-form analytical expressions have been derived for a flip-chip bonded conductor-backed and top-shielded CPW transmission line. The obtained expressions are used to analyse the volume effect of the FE thin film and the gap between the flip-chip and the CPW resonator on the tuning properties of the device. It has been found that large frequency modulation of the resonator produces impedance mismatch, which can considerably enhance the insertion loss of high-performance HTS microwave devices. Analysis also suggests that, for electrically tunable devices, flip-chip bonded FE thin films on HTS CPW devices provide a relatively higher performance...

  18. Characterizing the Soldering Alloy Type In–Ag–Ti and the Study of Direct Soldering of SiC Ceramics and Copper

    Directory of Open Access Journals (Sweden)

    Roman Koleňák

    2018-04-01

    Full Text Available The aim of the research was to characterize the soldering alloy In–Ag–Ti type, and to study the direct soldering of SiC ceramics and copper. The In10Ag4Ti solder has a broad melting interval, which mainly depends on its silver content. The liquid point of the solder is 256.5 °C. The solder microstructure is composed of a matrix with solid solution (In, in which the phases of titanium (Ti3In4 and silver (AgIn2 are mainly segregated. The tensile strength of the solder is approximately 13 MPa. The strength of the solder increased with the addition of Ag and Ti. The solder bonds with SiC ceramics, owing to the interaction between active In metal and silicon infiltrated in the ceramics. XRD analysis has proven the interaction of titanium with ceramic material during the formation of the new minority phases of titanium silicide—SiTi and titanium carbide—C5Ti8. In and Ag also affect bond formation with the copper substrate. Two new phases were also observed in the bond interphase—(CuAg6In5 and (AgCuIn2. The average shear strength of a combined joint of SiC–Cu, fabricated with In10Ag4Ti solder, was 14.5 MPa. The In–Ag–Ti solder type studied possesses excellent solderability with several metallic and ceramic materials.

  19. Study of Diffusion Barrier for Solder/ n-Type Bi2Te3 and Bonding Strength for p- and n-Type Thermoelectric Modules

    Science.gov (United States)

    Lin, Wen-Chih; Li, Ying-Sih; Wu, Albert T.

    2018-01-01

    This paper investigates the interfacial reaction between Sn and Sn3Ag0.5Cu (SAC305) solder on n-type Bi2Te3 thermoelectric material. An electroless Ni-P layer successfully suppressed the formation of porous SnTe intermetallic compound at the interface. The formation of the layers between Bi2Te3 and Ni-P indicates that Te is the dominant diffusing species. Shear tests were conducted on both Sn and SAC305 solder on n- and p-type Bi2Te3 with and without a Ni-P barrier layer. Without a Ni-P layer, porous SnTe would result in a more brittle fracture. A comparison of joint strength for n- and p-type thermoelectric modules is evaluated by the shear test. Adding a diffusion barrier increases the mechanical strength by 19.4% in n-type and 74.0% in p-type thermoelectric modules.

  20. Effect of solder bump size on interfacial reactions during soldering between Pb-free solder and Cu and Ni/ Pd/ Au surface finishes

    International Nuclear Information System (INIS)

    NorAkmal, F.; Ourdjini, A.; Azmah Hanim, M.A.; Siti Aisha, I.; Chin, Y.T.

    2007-01-01

    Flip chip technology provides the ultimate in high I/ O-density and count with superior electrical performance for interconnecting electronic components. Therefore, the study of the intermetallic compounds was conducted to investigate the effect of solder bumps sizes on several surface finishes which are copper and Electroless Nickel/ Electroless Palladium/ Immersion Gold (ENEPIG) which is widely used in electronics packaging as surface finish for flip-chip application nowadays. In this research, field emission scanning electron microscopy (FESEM) analysis was conducted to analyze the morphology and composition of intermetallic compounds (IMCs) formed at the interface between the solder and UBM. The IMCs between the SAC lead-free solder with Cu surface finish after reflow were mainly (Cu, Ni) 6 Sn 5 and Cu 6 Sn 5 . While the main IMCs formed between lead-free solder on ENEPIG surface finish are (Ni, Cu) 3 Sn 4 and Ni 3 Sn 4 . The results from FESEM with energy dispersive x-ray (EDX) have revealed that isothermal aging at 150 degree Celsius has caused the thickening and coarsening of IMCs as well as changing them into more spherical shape. The thickness of the intermetallic compounds in both finishes investigated was found to be higher in solders with smaller bump size. From the experimental results, it also appears that the growth rate of IMCs is higher when soldering on copper compared to ENEPIG finish. Besides that, the results also showed that the thickness of intermetallic compounds was found to be proportional to isothermal aging duration. (author)

  1. Fabrication of a microfluidic chip by UV bonding at room temperature for integration of temperature-sensitive layers

    Science.gov (United States)

    Schlautmann, S.; Besselink, G. A. J.; Radhakrishna Prabhu, G.; Schasfoort, R. B. M.

    2003-07-01

    A method for the bonding of a microfluidic device at room temperature is presented. The wafer with the fluidic structures was bonded to a sensor wafer with gold pads by means of adhesive bonding, utilizing an UV-curable glue layer. To avoid filling the fluidic channels with the glue, a stamping process was developed which allows the selective application of a thin glue layer. In this way a microfluidic glass chip was fabricated that could be used for performing surface plasmon resonance measurements without signs of leakage. The advantage of this method is the possibility of integration of organic layers as well as other temperature-sensitive layers into a microfluidic glass device.

  2. Influence of Difference Solders Volume on Intermetallic Growth of Sn-4.0Ag-0.5Cu/ENEPIG

    Directory of Open Access Journals (Sweden)

    Saliza Azlina O.

    2016-01-01

    Full Text Available In recent years, portable electronic packaging products such as smart phones, tablets, notebooks and other gadgets have been developed with reduced size of component packaging, light weight, high speed and with enhanced performance. Thus, flip chip technology with smaller solder sphere sizes that would produce fine solder joint interconnections have become essential in order to fulfill these miniaturization requirements. This study investigates the interfacial reactions and intermetallics formation during reflow soldering and isothermal aging between Sn-4.0Ag-0.5Cu (SAC405 and electroless nickel/immersion palladium/immersion gold (EN(PEPIG. Solder diameters of 300 μm and 700 μm were used to compare the effect of solder volume on the solder joint microstructure. The solid state isothermal aging was performed at 125°C starting from 250 hours until 2000 hours. The results revealed that only (Cu,Ni6Sn5 IMC was found at the interface during reflow soldering while both (Cu,Ni6Sn5 and (Ni,Cu3Sn4 IMC have been observed after aging process. Smaller solder sizes produced thinner IMC than larger solder joints investigated after reflow soldering, whereas the larger solders produced thinner IMC than the smaller solders after isothermal aging. Aging duration of solder joints has been found to be increase the IMC’s thickness and changed the IMC morphologies to spherical-shaped, compacted and larger grain size.

  3. Low-temperature bonded glass-membrane microfluidic device for in vitro organ-on-a-chip cell culture models

    Science.gov (United States)

    Pocock, Kyall J.; Gao, Xiaofang; Wang, Chenxi; Priest, Craig; Prestidge, Clive A.; Mawatari, Kazuma; Kitamori, Takehiko; Thierry, Benjamin

    2015-12-01

    The integration of microfluidics with living biological systems has paved the way to the exciting concept of "organson- a-chip", which aims at the development of advanced in vitro models that replicate the key features of human organs. Glass based devices have long been utilised in the field of microfluidics but the integration of alternative functional elements within multi-layered glass microdevices, such as polymeric membranes, remains a challenge. To this end, we have extended a previously reported approach for the low-temperature bonding of glass devices that enables the integration of a functional polycarbonate porous membrane. The process was initially developed and optimised on specialty low-temperature bonding equipment (μTAS2001, Bondtech, Japan) and subsequently adapted to more widely accessible hot embosser units (EVG520HE Hot Embosser, EVG, Austria). The key aspect of this method is the use of low temperatures compatible with polymeric membranes. Compared to borosilicate glass bonding (650 °C) and quartz/fused silica bonding (1050 °C) processes, this method maintains the integrity and functionality of the membrane (Tg 150 °C for polycarbonate). Leak tests performed showed no damage or loss of integrity of the membrane for up to 150 hours, indicating sufficient bond strength for long term cell culture. A feasibility study confirmed the growth of dense and functional monolayers of Caco-2 cells within 5 days.

  4. Low-temperature bonding process for the fabrication of hybrid glass-membrane organ-on-a-chip devices

    Science.gov (United States)

    Pocock, Kyall J.; Gao, Xiaofang; Wang, Chenxi; Priest, Craig; Prestidge, Clive A.; Mawatari, Kazuma; Kitamori, Takehiko; Thierry, Benjamin

    2016-10-01

    The integration of microfluidics with living biological systems has paved the way to the exciting concept of "organs-on-a-chip," which aims at the development of advanced in vitro models that replicate the key features of human organs. Glass-based devices have long been utilized in the field of microfluidics but the integration of alternative functional elements within multilayered glass microdevices, such as polymeric membranes, remains a challenge. To this end, we have extended a previously reported approach for the low-temperature bonding of glass devices that enables the integration of a functional polycarbonate porous membrane. The process was initially developed and optimized on specialty low-temperature bonding equipment (μTAS2001, Bondtech, Japan) and subsequently adapted to more widely accessible hot embosser units (EVG520HE Hot Embosser, EVG, Austria). The key aspect of this method is the use of low temperatures compatible with polymeric membranes. Compared to borosilicate glass bonding (650°C) and quartz/fused silica bonding (1050°C) processes, this method maintains the integrity and functionality of the membrane (Tg 150°C for polycarbonate). Leak tests performed showed no damage or loss of integrity of the membrane for up to 150 h, indicating sufficient bond strength for long-term cell culture. A feasibility study confirmed the growth of dense and functional monolayers of Caco-2 cells within 5 days.

  5. Self-Assembly of Chip-Size Components with Cavity Structures: High-Precision Alignment and Direct Bonding without Thermal Compression for Hetero Integration

    Directory of Open Access Journals (Sweden)

    Mitsumasa Koyanagi

    2011-02-01

    Full Text Available New surface mounting and packaging technologies, using self-assembly with chips having cavity structures, were investigated for three-dimensional (3D and hetero integration of complementary metal-oxide semiconductors (CMOS and microelectromechanical systems (MEMS. By the surface tension of small droplets of 0.5 wt% hydrogen fluoride (HF aqueous solution, the cavity chips, with a side length of 3 mm, were precisely aligned to hydrophilic bonding regions on the surface of plateaus formed on Si substrates. The plateaus have micro-channels to readily evaporate and fully remove the liquid from the cavities. The average alignment accuracy of the chips with a 1 mm square cavity was found to be 0.4 mm. The alignment accuracy depends, not only on the area of the bonding regions on the substrates and the length of chip periphery without the widths of channels in the plateaus, but also the area wetted by the liquid on the bonding regions. The precisely aligned chips were then directly bonded to the substrates at room temperature without thermal compression, resulting in a high shear bonding strength of more than 10 MPa.

  6. In the photograph, one can see the interconnection from one readout chip to the flexible cable realized with ultrasonic wire bonds (25 microns).

    CERN Multimedia

    Saba, A

    2006-01-01

    2 ladders are connected via a multi layer aluminium polyimide flexible cable with a multi chip module containing several custom designed ASICs. The production of the flexible cable was developed and carrier out at CERN. It provides signal and data lines as well as power to the individual readout chipswith a total thickness of only 220 microns. In the photograph, one can see the interconnection from one readout chip to the flexible cable realized with ultrasonic wire bonds (25 microns).

  7. Comparison of Ultrasonic Welding and Thermal Bonding for the Integration of Thin Film Metal Electrodes in Injection Molded Polymeric Lab-on-Chip Systems for Electrochemistry

    Directory of Open Access Journals (Sweden)

    Marco Matteucci

    2016-10-01

    Full Text Available We compare ultrasonic welding (UW and thermal bonding (TB for the integration of embedded thin-film gold electrodes for electrochemical applications in injection molded (IM microfluidic chips. The UW bonded chips showed a significantly superior electrochemical performance compared to the ones obtained using TB. Parameters such as metal thickness of electrodes, depth of electrode embedding, delivered power, and height of energy directors (for UW, as well as pressure and temperature (for TB, were systematically studied to evaluate the two bonding methods and requirements for optimal electrochemical performance. The presented technology is intended for easy and effective integration of polymeric Lab-on-Chip systems to encourage their use in research, commercialization and education.

  8. Development of n+-in-p planar pixel quadsensor flip-chipped with FE-I4 readout ASICs

    International Nuclear Information System (INIS)

    Unno, Y.; Hanagaki, K.; Hori, R.; Ikegami, Y.; Nakamura, K.; Takubo, Y.; Kamada, S.; Yamamura, K.; Yamamoto, H.; Takashima, R.; Tojo, J.; Kono, T.; Nagai, R.; Saito, S.; Sugibayashi, K.; Hirose, M.; Jinnouchi, O.; Sato, S.; Sawai, H.; Hara, K.

    2017-01-01

    We have developed flip-chip modules applicable to the pixel detector for the HL-LHC. New radiation-tolerant n + -in-p planar pixel sensors of a size of four FE-I4 application-specific integrated circuits (ASICs) are laid out in a 6-in wafer. Variation in readout connection for the pixels at the boundary of ASICs is implemented in the design of quadsensors. Bump bonding technology is developed for four ASICs onto one quadsensor. Both sensors and ASICs are thinned to 150 μm before bump bonding, and are held flat with vacuum chucks. Using lead-free SnAg solder bumps, we encounter deficiency with large areas of disconnected bumps after thermal stress treatment, including irradiation. Surface oxidation of the solder bumps is identified as a critical source of this deficiency after bump bonding trials, using SnAg bumps with solder flux, indium bumps, and SnAg bumps with a newly-introduced hydrogen-reflow process. With hydrogen-reflow, we establish flux-less bump bonding technology with SnAg bumps, appropriate for mass production of the flip-chip modules with thin sensors and thin ASICs.

  9. Characteristics of solder joints under fatigue loads using piezomechanical actuation

    Science.gov (United States)

    Shim, Dong-Jin; Spearing, S. Mark

    2003-07-01

    Crack initiation and growth characteristics of solder joints under fatigue loads are investigated using piezomechanical actuation. Cracks in solder joints, which can cause failure in microelectronics components, are induced via piezoelectricity in piezo-ceramic bonded joints. Lead-zirconate-titanate ceramic plates and eutectic Sn-Pb solder bonded in a double-lap shear configuration are used in the investigation. Electric field across each piezo-ceramic plate is applied such that shear stresses/strains are induced in the solder joints. The experiments show that cracks initiate in the solder joints around defects such as voids and grow in length until they coalesce with other cracks from adjacent voids. These observations are compared with the similar thermal cycling tests from the literature to show feasibility and validity of the current method in investigating the fatigue characteristics of solder joints. In some specimens, cracks in the piezo-ceramic plates are observed, and failure in the specimens generally occurred due to piezo-ceramic plate fracture. The issues encountered in implementing this methodology such as low actuation and high processing temperatures are further discussed.

  10. Development of a soft-soldering system for aluminum

    Science.gov (United States)

    Falke, W. L.; Lee, A. Y.; Neumeier, L. A.

    1983-03-01

    The method employs application of a thin nickel copper alloy coating to the substrate, which enables the tin lead solders to wet readily and spread over the areas to be joined. The aluminum substrate is mechanically or chemically cleaned to facilitate bonding to a minute layer of zinc that is subsequently applied, with an electroless zincate solution. The nickel copper alloy (30 to 70 pct Ni) coating is then applied electrolytically over the zinc, using immersion cell or brush coating techniques. Development of acetate electrolytes has permitted deposition of the proper alloys coatings. The coated areas can then be readily joined with conventional tin lead solders and fluxs. The joints so formed are ductile, strong, and relatively corrosion resistant, and exhibit strengths equivalent to those formed on copper and brass when the same solders and fluxes are used. The method has also been employed to soft solder magnesium alloys.

  11. On the use of OSL of wire-bond chip card modules for retrospective and accident dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Woda, Clemens [Helmholtz Zentrum Muenchen - German Research Centre for Environmental Health, Institute of Radiation Protection, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany)], E-mail: clemens.woda@helmholtz-muenchen.de; Spoettl, Thomas [Infineon Technologies AG, Wernerwerkstrasse 1, D-93049 Regensburg (Germany)

    2009-05-15

    The potential of optically stimulated luminescence of wire-bond chip card modules, used in health insurance, ID, cash and credit cards for retrospective and accident dosimetry is investigated. Chip card modules obtained directly from the producer, using a widely spread UV-cured epoxy product for encapsulation, are used as basis for the study. The radiation sensitivity is due to silica grains added to the epoxy for controlling the thixotropic properties. Luminescence properties are complex due to the presumed thermo-optical release of electrons from the epoxy and transfer into the silica. Best results and highest sensitivity are obtained by using no or only low preheat treatments. A high degree of fading of the OSL signal during storage at room temperature is observed, which is tentatively explained by the superposition of thermal decay of shallow OSL traps and athermal (anomalous) decay of deeper OSL traps. The dose response of the OSL signal shows exponentially saturating behaviour, with saturation doses of 77 Gy or 9.6 Gy, depending on pretreatment. Dose recovery tests show that given doses can be recovered within a deviation of {+-}14%, if measured signals are corrected for fading. The minimum detectable dose is estimated at {approx}3 mGy, {approx}10 mGy and {approx}20 mGy for readouts immediately, 1 day and 10 days after exposure, respectively.

  12. On the use of OSL of wire-bond chip card modules for retrospective and accident dosimetry

    International Nuclear Information System (INIS)

    Woda, Clemens; Spoettl, Thomas

    2009-01-01

    The potential of optically stimulated luminescence of wire-bond chip card modules, used in health insurance, ID, cash and credit cards for retrospective and accident dosimetry is investigated. Chip card modules obtained directly from the producer, using a widely spread UV-cured epoxy product for encapsulation, are used as basis for the study. The radiation sensitivity is due to silica grains added to the epoxy for controlling the thixotropic properties. Luminescence properties are complex due to the presumed thermo-optical release of electrons from the epoxy and transfer into the silica. Best results and highest sensitivity are obtained by using no or only low preheat treatments. A high degree of fading of the OSL signal during storage at room temperature is observed, which is tentatively explained by the superposition of thermal decay of shallow OSL traps and athermal (anomalous) decay of deeper OSL traps. The dose response of the OSL signal shows exponentially saturating behaviour, with saturation doses of 77 Gy or 9.6 Gy, depending on pretreatment. Dose recovery tests show that given doses can be recovered within a deviation of ±14%, if measured signals are corrected for fading. The minimum detectable dose is estimated at ∼3 mGy, ∼10 mGy and ∼20 mGy for readouts immediately, 1 day and 10 days after exposure, respectively.

  13. Estimate the thermomechanical fatigue life of two flip chip packages

    International Nuclear Information System (INIS)

    Pash, R.A.; Ullah, H.S.; Khan, M.Z.

    2005-01-01

    The continuing demand towards high density and low profile integrated circuit packaging has accelerated the development of flip chip structures as used in direct chip attach (DCA) technology, ball grid array (BOA) and chip scale package (CSP). In such structures the most widely used flip chip interconnects are solder joints. The reliability of flip chip structures largely depends on the reliability of solder joints. In this work solder joint fatigue life prediction for two chip scale packages is carried out. Elasto-plastic deformation behavior of the solder was simulated using ANSYS. Two dimensional plain strain finite element models were developed for each package to numerically compute the stress and total strain of the solder joints under temperature cycling. These stress and strain values are then used to predict the solder joint lifetime through modified Coffin Manson equation. The effect of solder joint's distance from edge of silicon die on life of the package is explored. The solder joint fatigue response is modeled for a typical temperature cycling of -60 to 140 degree C. (author)

  14. A new method for soldering particle-reinforced aluminum metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jinbin; Mu, Yunchao [Zhongyuan University of Technology, Zhengzhou 450007 (China); Luo, Xiangwei [Zhengzhou University, Zhengzhou 450002 (China); Niu, Jitai, E-mail: niujitai@163.com [Zhongyuan University of Technology, Zhengzhou 450007 (China)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer Soldering of 55% SiCp/Al composite and Kovar is first achieved in the world. Black-Right-Pointing-Pointer The nickel plating is required on the surface of the composites before soldering. Black-Right-Pointing-Pointer Low welding temperature is set to avoid overheating of the matrix. Black-Right-Pointing-Pointer Chemical and metallurgical bonding of composites and Kovar is carried out. Black-Right-Pointing-Pointer High tension strength of 225 MPa in soldering seam has been obtained. - Abstract: Soldering of aluminum metal matrix composites (Al-SiC) to other structural materials, or even to themselves, has proved unsuccessful mainly due to the poor wetting of these composites by conventional soldering alloys. This paper reports a new approach, which improves the wetting properties of these composites by molting solder alloys to promote stronger bonds. The new approach relies on nickel-plating of the composite's faying surface prior to application of a solder alloy. Based on this approach, an aluminum metal matrix composite containing 55 vol.% SiC particles is successfully soldered to a Fe-Ni-Co alloy (commercially known as Kovar 4J29). The solder material is a zinc-based alloy (Zn-Cd-Ag-Cu) with a melting point of about 400 Degree-Sign C. Microscopic examinations of the aluminum metal matrix composites (Al-MMCs)-Kovar interfaces show that the nickel-plating, prior to soldering, could noticeably enhance the reaction between the molten solder and composites. The fractography of the shear-tested samples revealed that fracture occurs within the composite (i.e. cohesive failure), indicating a good adhesion between the solder alloy and the Al-SiC composite.

  15. A new method for soldering particle-reinforced aluminum metal matrix composites

    International Nuclear Information System (INIS)

    Lu, Jinbin; Mu, Yunchao; Luo, Xiangwei; Niu, Jitai

    2012-01-01

    Highlights: ► Soldering of 55% SiCp/Al composite and Kovar is first achieved in the world. ► The nickel plating is required on the surface of the composites before soldering. ► Low welding temperature is set to avoid overheating of the matrix. ► Chemical and metallurgical bonding of composites and Kovar is carried out. ► High tension strength of 225 MPa in soldering seam has been obtained. - Abstract: Soldering of aluminum metal matrix composites (Al–SiC) to other structural materials, or even to themselves, has proved unsuccessful mainly due to the poor wetting of these composites by conventional soldering alloys. This paper reports a new approach, which improves the wetting properties of these composites by molting solder alloys to promote stronger bonds. The new approach relies on nickel-plating of the composite's faying surface prior to application of a solder alloy. Based on this approach, an aluminum metal matrix composite containing 55 vol.% SiC particles is successfully soldered to a Fe–Ni–Co alloy (commercially known as Kovar 4J29). The solder material is a zinc-based alloy (Zn–Cd–Ag–Cu) with a melting point of about 400 °C. Microscopic examinations of the aluminum metal matrix composites (Al-MMCs)–Kovar interfaces show that the nickel-plating, prior to soldering, could noticeably enhance the reaction between the molten solder and composites. The fractography of the shear-tested samples revealed that fracture occurs within the composite (i.e. cohesive failure), indicating a good adhesion between the solder alloy and the Al–SiC composite.

  16. Research on Defects Inspection of Solder Balls Based on Eddy Current Pulsed Thermography

    Directory of Open Access Journals (Sweden)

    Xiuyun Zhou

    2015-10-01

    Full Text Available In order to solve tiny defect detection for solder balls in high-density flip-chip, this paper proposed feasibility study on the effect of detectability as well as classification based on eddy current pulsed thermography (ECPT. Specifically, numerical analysis of 3D finite element inductive heat model is generated to investigate disturbance on the temperature field for different kind of defects such as cracks, voids, etc. The temperature variation between defective and non-defective solder balls is monitored for defects identification and classification. Finally, experimental study is carried on the diameter 1mm tiny solder balls by using ECPT and verify the efficacy of the technique.

  17. Damage behavior of SnAgCu/Cu solder joints subjected to thermomechanical cycling

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, H., E-mail: xiaohui2013@yahoo.com.cn; Li, X.Y.; Hu, Y.; Guo, F.; Shi, Y.W.

    2013-11-25

    Highlights: •A creep–fatigue damage model based on CDM was proposed. •Designed system includes load frame, strain measure device and damage test device. •Damage evolution of solder joints was a function of accumulated inelastic strain. •Damage of solder joints is an interaction between creep and low-cycle fatigue. -- Abstract: Thermomechanical fatigue damage is a progressive process of material degradation. The objective of this study was to investigate the damage behavior of SnAgCu/Cu solder joints under thermomechanical cycling. A damage model was proposed based on continuum damage mechanics (CDM). Based upon an analysis of displacements for flip-chip solder joints subjected to thermal cycling, a special bimetallic loading frame with single-solder joint samples was designed to simulate the service conditions of actual joints in electronic packages. The assembly, which allowed for strain measurements of an individual solder joint during temperature cycling, was used to investigate the impact of stress–strain cycling on the damage behavior of SnAgCu/Cu solder joints. The characteristic parameters of the damage model were determined through thermomechanical cycling and strain measurement tests. The damage variable D = 1 − R{sub 0}/R was selected, and values for it were obtained using a four-probe method for the single-solder joint samples every dozen cycles during thermomechanical cycling tests to verify the model. The results showed that the predicted damage was in good agreement with the experimental results. The damage evolution law proposed here is a function of inelastic strain, and the results showed that the damage rate of SnAgCu/Cu solder joints increased as the range of the applied strain increased. In addition, the microstructure evolution of the solder joints was analyzed using scanning electron microscopy, which provided the microscopic explanation for the damage evolution law of SnAgCu/Cu solder joints.

  18. Damage behavior of SnAgCu/Cu solder joints subjected to thermomechanical cycling

    International Nuclear Information System (INIS)

    Xiao, H.; Li, X.Y.; Hu, Y.; Guo, F.; Shi, Y.W.

    2013-01-01

    Highlights: •A creep–fatigue damage model based on CDM was proposed. •Designed system includes load frame, strain measure device and damage test device. •Damage evolution of solder joints was a function of accumulated inelastic strain. •Damage of solder joints is an interaction between creep and low-cycle fatigue. -- Abstract: Thermomechanical fatigue damage is a progressive process of material degradation. The objective of this study was to investigate the damage behavior of SnAgCu/Cu solder joints under thermomechanical cycling. A damage model was proposed based on continuum damage mechanics (CDM). Based upon an analysis of displacements for flip-chip solder joints subjected to thermal cycling, a special bimetallic loading frame with single-solder joint samples was designed to simulate the service conditions of actual joints in electronic packages. The assembly, which allowed for strain measurements of an individual solder joint during temperature cycling, was used to investigate the impact of stress–strain cycling on the damage behavior of SnAgCu/Cu solder joints. The characteristic parameters of the damage model were determined through thermomechanical cycling and strain measurement tests. The damage variable D = 1 − R 0 /R was selected, and values for it were obtained using a four-probe method for the single-solder joint samples every dozen cycles during thermomechanical cycling tests to verify the model. The results showed that the predicted damage was in good agreement with the experimental results. The damage evolution law proposed here is a function of inelastic strain, and the results showed that the damage rate of SnAgCu/Cu solder joints increased as the range of the applied strain increased. In addition, the microstructure evolution of the solder joints was analyzed using scanning electron microscopy, which provided the microscopic explanation for the damage evolution law of SnAgCu/Cu solder joints

  19. Knudsen pump produced via silicon deep RIE, thermal oxidation, and anodic bonding processes for on-chip vacuum pumping

    Science.gov (United States)

    Van Toan, Nguyen; Inomata, Naoki; Trung, Nguyen Huu; Ono, Takahito

    2018-05-01

    This work describes the fabrication and evaluation of the Knudsen pump for on-chip vacuum pumping that works based on the principle of a thermal transpiration. Three AFM (atomic force microscope) cantilevers are integrated into small chambers with a size of 5 mm  ×  3 mm  ×  0.4 mm for the pump’s evaluation. Knudsen pump is fabricated using deep RIE (reactive ion etching), wet thermal oxidation and anodic bonding processes. The fabricated device is evaluated by monitoring the quality (Q) factor of the integrated cantilevers. The Q factor of the cantilever is increased from 300 -1150 in cases without and with a temperature difference approximately 25 °C between the top (the hot side at 40 °C) and bottom (the cold side at 15 °C) sides of the fabricated device, respectively. The evacuated chamber pressure of around 10 kPa is estimated from the Q factor of the integrated cantilevers.

  20. A full-wafer fabrication process for glass microfluidic chips with integrated electroplated electrodes by direct bonding of dry film resist

    International Nuclear Information System (INIS)

    Vulto, Paul; Urban, G A; Huesgen, Till; Albrecht, Björn

    2009-01-01

    A full-wafer process is presented for fast and simple fabrication of glass microfluidic chips with integrated electroplated electrodes. The process employs the permanent dry film resist (DFR) Ordyl SY300 to create microfluidic channels, followed by electroplating of silver and subsequent chlorination. The dry film resist is bonded directly to a second substrate, without intermediate gluing layers, only by applying pressure and moderate heating. The process of microfluidic channel fabrication, electroplating and wafer bonding can be completed within 1 day, thus making it one of the fastest and simplest full-wafer fabrication processes. (note)

  1. Scalable Manufacturing of Solderable and Stretchable Physiologic Sensing Systems.

    Science.gov (United States)

    Kim, Yun-Soung; Lu, Jesse; Shih, Benjamin; Gharibans, Armen; Zou, Zhanan; Matsuno, Kristen; Aguilera, Roman; Han, Yoonjae; Meek, Ann; Xiao, Jianliang; Tolley, Michael T; Coleman, Todd P

    2017-10-01

    Methods for microfabrication of solderable and stretchable sensing systems (S4s) and a scaled production of adhesive-integrated active S4s for health monitoring are presented. S4s' excellent solderability is achieved by the sputter-deposited nickel-vanadium and gold pad metal layers and copper interconnection. The donor substrate, which is modified with "PI islands" to become selectively adhesive for the S4s, allows the heterogeneous devices to be integrated with large-area adhesives for packaging. The feasibility for S4-based health monitoring is demonstrated by developing an S4 integrated with a strain gauge and an onboard optical indication circuit. Owing to S4s' compatibility with the standard printed circuit board assembly processes, a variety of commercially available surface mount chip components, such as the wafer level chip scale packages, chip resistors, and light-emitting diodes, can be reflow-soldered onto S4s without modifications, demonstrating the versatile and modular nature of S4s. Tegaderm-integrated S4 respiration sensors are tested for robustness for cyclic deformation, maximum stretchability, durability, and biocompatibility for multiday wear time. The results of the tests and demonstration of the respiration sensing indicate that the adhesive-integrated S4s can provide end users a way for unobtrusive health monitoring. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Al and Si Alloying Effect on Solder Joint Reliability in Sn-0.5Cu for Automotive Electronics

    Science.gov (United States)

    Hong, Won Sik; Oh, Chulmin; Kim, Mi-Song; Lee, Young Woo; Kim, Hui Joong; Hong, Sung Jae; Moon, Jeong Tak

    2016-12-01

    To suppress the bonding strength degradation of solder joints in automotive electronics, we proposed a mid-temperature quaternary Pb-free Sn-0.5Cu solder alloy with minor Pd, Al, Si and Ge alloying elements. We manufactured powders and solder pastes of Sn-0.5Cu-(0.01,0.03)Al-0.005Si-(0.006-0.007)Ge alloys ( T m = 230°C), and vehicle electronic control units used for a flame-retardant-4 printed circuit board with an organic solderability preservative finish were assembled by a reflow soldering process. To investigate the degradation properties of solder joints used in engine compartments, thermal cycling tests were conducted from -40°C to 125°C (10 min dwell) for 1500 cycles. We also measured the shear strength of the solder joints in various components and observed the microstructural evolution of the solder joints. Based on these results, intermetallic compound (IMC) growth at the solder joints was suppressed by minor Pd, Al and Si additions to the Sn-0.5Cu alloy. After 1500 thermal cycles, IMC layers thicknesses for 100 parts per million (ppm) and 300 ppm Al alloy additions were 6.7 μm and 10 μm, compared to the as-reflowed bonding thicknesses of 6 μm and 7 μm, respectively. Furthermore, shear strength degradation rates for 100 ppm and 300 ppm Al(Si) alloy additions were at least 19.5%-26.2%. The cause of the improvement in thermal cycling reliability was analyzed using the (Al,Cu)-Sn, Si-Sn and Al-Sn phases dispersed around the Cu6Sn5 intermetallic at the solder matrix and bonding interfaces. From these results, we propose the possibility of a mid-temperature Sn-0.5Cu(Pd)-Al(Si)-Ge Pb-free solder for automotive engine compartment electronics.

  3. In-situ study of electromigration-induced grain rotation in Pb-free solder joint by synchrotron microdiffraction

    International Nuclear Information System (INIS)

    Chen, Kai; Tamura, Nobumichi; Tu, King-Ning

    2008-01-01

    The rotation of Sn grains in Pb-free flip chip solder joints hasn't been reported in literature so far although it has been observed in Sn strips. In this letter, we report the detailed study of the grain orientation evolution induced by electromigration by synchrotron based white beam X-ray microdiffraction. It is found that the grains in solder joint rotate more slowly than in Sn strip even under higher current density. On the other hand, based on our estimation, the reorientation of the grains in solder joints also results in the reduction of electric resistivity, similar to the case of Sn strip. We will also discuss the reason why the electric resistance decreases much more in strips than in the Sn-based solders, and the different driving force for the grain growth in solder joint and in thin film interconnect lines

  4. In-situ study of electromigration-induced grain rotation in Pb-free solder joint by synchrotron microdiffraction

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Kai; Tamura, Nobumichi; Tu, King-Ning

    2008-10-31

    The rotation of Sn grains in Pb-free flip chip solder joints hasn't been reported in literature so far although it has been observed in Sn strips. In this letter, we report the detailed study of the grain orientation evolution induced by electromigration by synchrotron based white beam X-ray microdiffraction. It is found that the grains in solder joint rotate more slowly than in Sn strip even under higher current density. On the other hand, based on our estimation, the reorientation of the grains in solder joints also results in the reduction of electric resistivity, similar to the case of Sn strip. We will also discuss the reason why the electric resistance decreases much more in strips than in the Sn-based solders, and the different driving force for the grain growth in solder joint and in thin film interconnect lines.

  5. On the problem of soldering refractory metals with silver-containing solders

    International Nuclear Information System (INIS)

    Anikeev, E.F.; Andryushchenko, V.I.; Chepelenko, V.N.; Batov, V.M.

    1981-01-01

    The processes of wetting, spreading and interphase interactions of copper-silver liquid alloys alloyed with Ni and Si, with niobium, tantalum, molybdenum, tungsten, 12Kh18N10T steel and nickel are studied. It has been determined that Ni or Si additions into the copper-silver solder improve the wetting and adhesion. When soldering with the alloy containing Ni additions, the strength of a soldered Joint grows with the increase of soldering duration while soldering with the alloy containing Si additions, the strength decreases. That is why Ni-containing solders are preferable for soldering thick-walled structures, and Si-containing solders - for thin-walled structures [ru

  6. Transient Liquid Phase Behavior of Sn-Coated Cu Particles and Chip Bonding using Paste Containing the Particles

    Directory of Open Access Journals (Sweden)

    Hwang Jun Ho

    2017-06-01

    Full Text Available Sn-coated Cu particles were prepared as a filler material for transient liquid phase (TLP bonding. The thickness of Sn coating was controlled by controlling the number of plating cycles. The Sn-coated Cu particles best suited for TLP bonding were fabricated by Sn plating thrice, and the particles showed a pronounced endothermic peak at 232°C. The heating of the particles for just 10 s at 250°C destroyed the initial core-shell structure and encouraged the formation of Cu-Sn intermetallic compounds. Further, die bonding was also successfully performed at 250°C under a slight bonding pressure of around 0.1 MPa using a paste containing the particles. The bonding time of 30 s facilitated the bonding of Sn-coated Cu particles to the Au surface and also increased the probability of network formation between particles.

  7. Solder joint technology materials, properties, and reliability

    CERN Document Server

    Tu, King-Ning

    2007-01-01

    Solder joints are ubiquitous in electronic consumer products. The European Union has a directive to ban the use of Pb-based solders in these products on July 1st, 2006. There is an urgent need for an increase in the research and development of Pb-free solders in electronic manufacturing. For example, spontaneous Sn whisker growth and electromigration induced failure in solder joints are serious issues. These reliability issues are quite complicated due to the combined effect of electrical, mechanical, chemical, and thermal forces on solder joints. To improve solder joint reliability, the science of solder joint behavior under various driving forces must be understood. In this book, the advanced materials reliability issues related to copper-tin reaction and electromigration in solder joints are emphasized and methods to prevent these reliability problems are discussed.

  8. Electromigration-induced back stress in critical solder length for three-dimensional integrated circuits

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Y. T.; Hsu, H. H.; Wu, Albert T., E-mail: atwu@ncu.edu.tw [Department of Chemical and Materials Engineering, National Central University, Jhongli City 320, Taiwan (China)

    2014-01-21

    Because of the miniaturization of electronic devices, the reliability of electromigration has become a major concern when shrinking the solder dimensions in flip-chip joints. Fast reaction between solders and electrodes causes intermetallic compounds (IMCs) to form, which grow rapidly and occupy entire joints when solder volumes decrease. In this study, U-grooves were fabricated on Si chips as test vehicles. An electrode-solder-electrode sandwich structure was fabricated by using lithography and electroplating. Gaps exhibiting well-defined dimensions were filled with Sn3.5Ag solders. The gaps between the copper electrodes in the test sample were limited to less than 15 μm to simulate microbumps. The samples were stressed at various current densities at 100 °C, 125 °C, and 150 °C. The morphological changes of the IMCs were observed, and the dimensions of the IMCs were measured to determine the kinetic growth of IMCs. Therefore, this study focused on the influence of back stress caused by microstructural evolution in microbumps.

  9. Nanoscale Soldering of Positioned Carbon Nanotubes using Highly Conductive Electron Beam Induced Gold Deposition

    DEFF Research Database (Denmark)

    Madsen, Dorte Nørgaard; Mølhave, Kristian; Mateiu, Ramona Valentina

    2003-01-01

    We have developed an in-situ method for controlled positioning of carbon nanotubes followed by highly conductive contacting of the nanotubes, using electron beam assisted deposition of gold. The positioning and soldering process takes place inside an Environmental Scanning Electron Microscope (E...... in a carbon matrix. Nanoscale soldering of multi-walled carbon nanotubes (MWNT) onto microelectrodes was achieved by deposition of a conducting gold line across a contact point between nanotube and electrode. The solderings were found to be mechanically stronger than the carbon nanotubes. We have positioned...... MWNTs to bridge the gap between two electrodes, and formed soldering bonds between the tube and each of the electrodes. All nanotube bridges showed ohmic resistances in the range 10-30 kΩ. We observed no increase in resistance after exposing the MWNT bridge to air for days....

  10. Dye-enhanced protein solders and patches in laser-assisted tissue welding.

    Science.gov (United States)

    Small, W; Heredia, N J; Maitland, D J; Da Silva, L B; Matthews, D L

    1997-01-01

    This study examines the use of dye-enhanced protein bonding agents in 805 nm diode laser-assisted tissue welding. A comparison of an albumin liquid solder and collagen solid-matrix patches used to repair arteriotomies in an in vitro porcine model is presented. Extrinsic bonding media in the form of solders and patches have been used to enhance the practice of laser tissue welding. Preferential absorption of the laser wavelength has been achieved by the incorporation of chromophores. Both the solder and the patch included indocyanine green dye (ICG) to absorb the 805 nm continuous-wave diode laser light used to perform the welds. Solder-mediated welds were divided into two groups (high power/short exposure and low power/long exposure), and the patches were divided into three thickness groups ranging from 0.1 to 1.3 mm. The power used to activate the patches was constant, but the exposure time was increased with patch thickness. Burst pressure results indicated that solder-mediated and patched welds yielded similar average burst strengths in most cases, but the patches provided a higher success rate (i.e., more often exceeded 150 mmHg) and were more consistent (i.e., smaller standard deviation) than the solder. The strongest welds were obtained using 1.0-1.3 mm thick patches, while the high power/short exposure solder group was the weakest. Though the solder and patches yielded similar acute weld strengths, the solid-matrix patches facilitated the welding process and provided consistently strong welds. The material properties of the extrinsic agents influenced their performance.

  11. Investigation Of The Effects Of Reflow Profile Parameters On Lead-free Solder Bump Volumes And Joint Integrity

    Science.gov (United States)

    Amalu, E. H.; Lui, Y. T.; Ekere, N. N.; Bhatti, R. S.; Takyi, G.

    2011-01-01

    The electronics manufacturing industry was quick to adopt and use the Surface Mount Technology (SMT) assembly technique on realization of its huge potentials in achieving smaller, lighter and low cost product implementations. Increasing global customer demand for miniaturized electronic products is a key driver in the design, development and wide application of high-density area array package format. Electronic components and their associated solder joints have reduced in size as the miniaturization trend in packaging continues to be challenged by printing through very small stencil apertures required for fine pitch flip-chip applications. At very narrow aperture sizes, solder paste rheology becomes crucial for consistent paste withdrawal. The deposition of consistent volume of solder from pad-to-pad is fundamental to minimizing surface mount assembly defects. This study investigates the relationship between volume of solder paste deposit (VSPD) and the volume of solder bump formed (VSBF) after reflow, and the effect of reflow profile parameters on lead-free solder bump formation and the associated solder joint integrity. The study uses a fractional factorial design (FFD) of 24-1 Ramp-Soak-Spike reflow profile, with all main effects and two-way interactions estimable to determine the optimal factorial combination. The results from the study show that the percentage change in the VSPD depends on the combination of the process parameters and reliability issues could become critical as the size of solder joints soldered on the same board assembly vary greatly. Mathematical models describe the relationships among VSPD, VSBF and theoretical volume of solder paste. Some factors have main effects across the volumes and a number of interactions exist among them. These results would be useful for R&D personnel in designing and implementing newer applications with finer-pitch interconnect.

  12. Handbook of machine soldering SMT and TH

    CERN Document Server

    Woodgate, Ralph W

    1996-01-01

    A shop-floor guide to the machine soldering of electronics Sound electrical connections are the operational backbone of every piece of electronic equipment-and the key to success in electronics manufacturing. The Handbook of Machine Soldering is dedicated to excellence in the machine soldering of electrical connections. Self-contained, comprehensive, and down-to-earth, it cuts through jargon, peels away outdated notions, and presents all the information needed to select, install, and operate machine soldering equipment. This fully updated and revised volume covers all of the new technologies and processes that have emerged in recent years, most notably the use of surface mount technology (SMT). Supplemented with 200 illustrations, this thoroughly accessible text Describes reflow and wave soldering in detail, including reflow soldering of SMT boards and the use of nitrogen blankets * Explains the setup, operation, and maintenance of a variety of soldering machines * Discusses theory, selection, and control met...

  13. An integrated circuit with transmit beamforming flip-chip bonded to a 2-D CMUT array for 3-D ultrasound imaging.

    Science.gov (United States)

    Wygant, Ira O; Jamal, Nafis S; Lee, Hyunjoo J; Nikoozadeh, Amin; Oralkan, Omer; Karaman, Mustafa; Khuri-Yakub, Butrus T

    2009-10-01

    State-of-the-art 3-D medical ultrasound imaging requires transmitting and receiving ultrasound using a 2-D array of ultrasound transducers with hundreds or thousands of elements. A tight combination of the transducer array with integrated circuitry eliminates bulky cables connecting the elements of the transducer array to a separate system of electronics. Furthermore, preamplifiers located close to the array can lead to improved receive sensitivity. A combined IC and transducer array can lead to a portable, high-performance, and inexpensive 3-D ultrasound imaging system. This paper presents an IC flip-chip bonded to a 16 x 16-element capacitive micromachined ultrasonic transducer (CMUT) array for 3-D ultrasound imaging. The IC includes a transmit beamformer that generates 25-V unipolar pulses with programmable focusing delays to 224 of the 256 transducer elements. One-shot circuits allow adjustment of the pulse widths for different ultrasound transducer center frequencies. For receiving reflected ultrasound signals, the IC uses the 32-elements along the array diagonals. The IC provides each receiving element with a low-noise 25-MHz-bandwidth transimpedance amplifier. Using a field-programmable gate array (FPGA) clocked at 100 MHz to operate the IC, the IC generated properly timed transmit pulses with 5-ns accuracy. With the IC flip-chip bonded to a CMUT array, we show that the IC can produce steered and focused ultrasound beams. We present 2-D and 3-D images of a wire phantom and 2-D orthogonal cross-sectional images (Bscans) of a latex heart phantom.

  14. Effect of Surface Finish of Substrate on Mechanical Reliability of in-48SN Solder Joints in Moems Package

    OpenAIRE

    Koo, Ja-Myeong; Jung, Seung-Boo

    2007-01-01

    Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/5920); International audience; Interfacial reactions and shear properties of the In-48Sn (in wt.%) ball grid array (BGA) solder joints after bonding were investigated with four different surface finishes of the substrate over an underlying Cu pad: electroplated Ni/Au (hereafter E-NG), electroless Ni/immersion Au (hereafter ENIG), immersion Ag (hereafter I-Ag) and organic solderability preservative (hereafte...

  15. Wall-slip effects in SnAgCu solder pastes used in electronics assembly applications

    International Nuclear Information System (INIS)

    Mallik, S.; Ekere, N.N.; Durairaj, R.; Marks, A.E.; Seman, A.

    2009-01-01

    Solder paste is the most important strategic bonding material used in the assembly of surface mount components in electronics manufacturing. As the trend towards miniaturisation of electronic products continues, there is an increasing demand for better understanding of the flow and deformation that is, the rheological behaviour of solder paste formulations. Wall slip plays an important role in characterising the flow behaviour of solder paste materials. The problem of wall slip arises due to the various attractive and repulsive forces acting between the solder particles and the walls of the measuring geometry. These interactions could lead to the presence of a thin solvent layer adjacent to the wall, which gives rise to slippage. In rheological measurements, slip effects can generally be avoided by using roughened surfaces for measuring geometries. In this paper, a novel technique is developed to study the effect of wall slip in the rheological measurements of lead-free solder paste. The viscosity and oscillatory data obtained for three different solder paste samples (from measuring geometries of different surface roughness) have been analysed and compared. In viscosity measurements, slip effects were dominant at low shear rates and the use of serrated surfaces was found to be quite effective in minimizing slip effects. Oscillatory measurements were also affected by roughening the surfaces of measuring geometries.

  16. Microfluidic DNA microarrays in PMMA chips: streamlined fabrication via simultaneous DNA immobilization and bonding activation by brief UV exposure

    DEFF Research Database (Denmark)

    Sabourin, David; Petersen, J; Snakenborg, Detlef

    2010-01-01

    This report presents and describes a simple and scalable method for producing functional DNA microarrays within enclosed polymeric, PMMA, microfluidic devices. Brief (30 s) exposure to UV simultaneously immobilized poly(T)poly(C)-tagged DNA probes to the surface of unmodified PMMA and activated...... the surface for bonding below the glass transition temperature of the bulk PMMA. Functionality and validation of the enclosed PMMA microarrays was demonstrated as 18 patients were correctly genotyped for all eight mutation sites in the HBB gene interrogated. The fabrication process therefore produced probes...... with desired hybridization properties and sufficient bonding between PMMA layers to allow construction of microfluidic devices. The streamlined fabrication method is suited to the production of low-cost microfluidic microarray-based diagnostic devices and, as such, is equally applicable to the development...

  17. Spectroscopic investigation of oxidized solder surfaces

    International Nuclear Information System (INIS)

    Song, Jenn-Ming; Chang-Chien, Yu-Chien; Huang, Bo-Chang; Chen, Wei-Ting; Shie, Chi-Rung; Hsu, Chuang-Yao

    2011-01-01

    Highlights: → UV-visible spectroscopy is successfully used to evaluate the degree of discoloring of solders. → The surface oxides of solders can also be identified by UV-visible absorption spectra. → The discoloration of solder surface can be correlated with optical characterization of oxides. → A strategy against discoloring by alloying was also suggested. - Abstract: For further understanding of the discoloration of solder surfaces due to oxidation during the assembly and operation of electronic devices, UV-vis and X-ray photoelectron spectroscopic analyses were applied to evaluate the degree of discoloring and identify the surface oxides. The decrease in reflectance of the oxidized solder surface is related to SnO whose absorption band is located within the visible region. A trace of P can effectively depress the discoloration of solders under both solid and semi-solid states through the suppression of SnO.

  18. Soldering of Mg Joints Using Zn-Al Solders

    Science.gov (United States)

    Gancarz, Tomasz; Berent, Katarzyna; Skuza, Wojciech; Janik, Katarzyna

    2018-04-01

    Magnesium has applications in the automotive and aerospace industries that can significantly contribute to greater fuel economy and environmental conservation. The Mg alloys used in the automotive industry could reduce mass by up to 70 pct, providing energy savings. However, alongside the advantages there are limitations and technological barriers to use Mg alloys. One of the advantages concerns phenomena occurring at the interface when joining materials investigated in this study, in regard to the effect of temperature and soldering time for pure Mg joints. Eutectic Zn-Al and Zn-Al alloys with 0.05 (wt pct) Li and 0.2 (wt pct) Na were used in the soldering process. The process was performed for 3, 5, and 8 minutes of contact, at temperatures of 425 °C, 450 °C, 475 °C, and 500 °C. Selected, solidified solder-substrate couples were cross-sectioned, and their interfacial microstructures were investigated by scanning electron microscopy. The experiment was designed to demonstrate the effect of time, temperature, and the addition of Li and Na on the kinetics of the dissolving Mg substrate. The addition of Li and Na to eutectic Zn-Al caused to improve mechanical properties. Higher temperatures led to reduced joint strength, which is caused by increased interfacial reaction.

  19. Fiscal 1998 achievement report on regional consortium research and development project. Venture business raising type regional consortium - Small business creation base type (Preparation of monodispersed spherical particles for solder materials for application to high density semiconductor packaging - 2nd year); 1998 nendo komitsudo handotai jisso no tame no tanbunsan kyukei handa ryushi no sakusei ni kansuru kenkyu seika hokokusho (dai 2 nendo)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    Fine solder grains have been developed, spherical in shape, uniform in diameter, high in dimensional precision, and high in surface cleanliness, which are necessary for the establishment of next-generation technologies of flip chip bonding and ball grid array which are indispensable for high-density high-reliability packaging of electronic devices such as LSI (large scale integration). Results attained in fiscal 1998 are described. A pulse pressure aided orifice injection method was used. Monodispersed grains are prepared for the Pb-63Sn solder and Sn-3.5Ag lead-free solder. In the case of a 200{mu}m-large orifice, the grain diameter was controlled to fall in the range of 190-210{mu}m and the accuracy was not lower than {+-}6{mu}m. The main goal of this project has been accomplished now that these figures were attained without a sorting process and satisfy the most rigorous conditions currently proposed by the industrial circle involved. The flow of hot liquid out of the orifice and the splitting process of grains were clarified by thermal hydraulic analysis. It was found that grains split and fly not because of instability due to Rayleigh surface waves but because of their liberation from surface tension when equipped with critical kinetic energy. (NEDO)

  20. Laser beam soldering of micro-optical components

    Science.gov (United States)

    Eberhardt, R.

    2003-05-01

    MOTIVATION Ongoing miniaturisation and higher requirements within optical assemblies and the processing of temperature sensitive components demands for innovative selective joining techniques. So far adhesive bonding has primarily been used to assemble and adjust hybrid micro optical systems. However, the properties of the organic polymers used for the adhesives limit the application of these systems. In fields of telecommunication and lithography, an enhancement of existing joining techniques is necessary to improve properties like humidity resistance, laserstability, UV-stability, thermal cycle reliability and life time reliability. Against this background laser beam soldering of optical components is a reasonable joining technology alternative. Properties like: - time and area restricted energy input - energy input can be controlled by the process temperature - direct and indirect heating of the components is possible - no mechanical contact between joining tool and components give good conditions to meet the requirements on a joining technology for sensitive optical components. Additionally to the laser soldering head, for the assembly of optical components it is necessary to include positioning units to adjust the position of the components with high accuracy before joining. Furthermore, suitable measurement methods to characterize the soldered assemblies (for instance in terms of position tolerances) need to be developed.

  1. Nano-soldering to single atomic layer

    Science.gov (United States)

    Girit, Caglar O [Berkeley, CA; Zettl, Alexander K [Kensington, CA

    2011-10-11

    A simple technique to solder submicron sized, ohmic contacts to nanostructures has been disclosed. The technique has several advantages over standard electron beam lithography methods, which are complex, costly, and can contaminate samples. To demonstrate the soldering technique graphene, a single atomic layer of carbon, has been contacted, and low- and high-field electronic transport properties have been measured.

  2. Safer Soldering Guidelines and Instructional Resources

    Science.gov (United States)

    Love, Tyler S.; Tomlinson, Joel

    2018-01-01

    Soldering is a useful and necessary process for many classroom, makerspace, Fab Lab, technology and engineering lab, and science lab activities. As described in this article, soldering can pose many safety risks without proper engineering controls, standard operating procedures, and direct instructor supervision. There are many safety hazards…

  3. Features of soldering of molybdenum a lols

    International Nuclear Information System (INIS)

    Grishin, V.L.; Rybkin, B.V.; Cherkasov, A.F.

    1980-01-01

    Soldering features of complex-alloy molybdenum alloys were investigated in comparison with alloys based on solid solutions. Soldering features of heterogeneous molybdenum base alloys were investigated using samples of 0.5-1.O mm sheets with the strain of about 95% made of ingots which had been smelted in arc vacuum furnaces. The soldering of samples was carried out in 5x1O -5 mm Hg vacuum using different sources of heating: radiation, electron-ray and contact. It was shown that heat-resisting soldered joints of heterogeneous molybdenum alloys could be produced using zirconium and niobium base solders containing the most effective hardeners of the parent material (titanum, vanadium, tantalum, molybdenum, tungsten). To preserve high mechanical properties of heterogeneous alloys it was expedient to use for welding local heating sources which permitted to decrease considerably temperature- time conditions of the process

  4. Development of Bi-base high-temperature Pb-free solders with second-phase dispersion: Thermodynamic calculation, microstructure, and interfacial reaction

    Science.gov (United States)

    Takaku, Yoshikazu; Ohnuma, Ikuo; Kainuma, Ryosuke; Yamada, Yasushi; Yagi, Yuji; Nishibe, Yuji; Ishida, Kiyohito

    2006-11-01

    Bismuth and its alloys are candidates for Pb-free high-temperature solders that can be substituted for conventional Pb-rich Pb-Sn solders (melting point (mp) = 573 583 K). However, inferior properties such as brittleness and weak bonding strength should be improved for practical use. To that end, BiCu-X (X=Sb, Sn, and Zn) Pb-free high-temperature solders are proposed. Miscibility gaps in liquid BiCu-X alloys were surveyed using the thermodynamic database ADAMIS (alloy database for micro-solders), and compositions of the BiCu-X solders were designed on the basis of calculation. In-situ composite solders that consist of a Bi-base matrix with fine intermetallic compound (IMC) particles were produced by gas-atomizing and melt-spinning methods. The interfacial reaction between in-situ composite solders and Cu or Ni substrates was investigated. The IMCs at the interface formed a thin, uniform layer, which is an appropriate morphology for a reliable solder joint.

  5. Solderability study of RABiTS-based YBCO coated conductors

    International Nuclear Information System (INIS)

    Zhang Yifei; Duckworth, Robert C.; Ha, Tam T.; Gouge, Michael J.

    2011-01-01

    Study examines the implication of solder and flux selection in YBCO splice joints. Focus is on commercially available RABiTS-based YBCO coated conductors. Solderability varied with solder and flux for three different stabilizations tested. Resistivity of stabilizer was dominant factor in splice joint resistance. Solder materials affected splice joint resistance when solderability was poor. The solderability of commercially available YBa 2 Cu 3 O 7-x (YBCO) coated conductors that were made from Rolling Assisted Biaxially Textured Substrates (RABiTS)-based templates was studied. The coated conductors, also known as second-generation (2G) high temperature superconductor (HTS) wires (in the geometry of flat tapes about 4 mm wide), were laminated with copper, brass, or stainless steel strips as stabilizers. To understand the factors that influence their solderability, surface profilometry and scanning electron microscopy were used to characterize the wire surfaces. The solderability of three solders, 52In48Sn, 67Bi33In, and 100In (wt.%), was evaluated using a standard test (IPC/ECA J-STD-002) and with two different commercial fluxes. It was found that the solderability varied with the solder and flux but the three different wires showed similar solderability for a fixed combination of solder and flux. Solder joints of the 2G wires were fabricated using the tools and the procedures recommended by the HTS wire manufacturer. The solder joints were made in a lap-joint geometry and with the superconducting sides of the two wires face-to-face. The electrical resistances of the solder joints were measured at 77 K, and the results were analyzed to qualify the soldering materials and evaluate the soldering process. It was concluded that although the selection of soldering materials affected the resistance of a solder joint, the resistivity of the stabilizer was the dominant factor.

  6. The constitutive response of three solder materials

    International Nuclear Information System (INIS)

    Perez-Bergquist, Alejandro G.; Cao Fang; Perez-Bergquist, Sara J.; Lopez, Mike F.; Trujillo, Carl P.; Cerreta, Ellen K.; Gray, George T.

    2012-01-01

    Highlights: ► The full constitutive response of three solder materials. ► Test temperatures from −196 °C to 60 °C and strain rates from 10 −3 to >10 3 s −1 . ► Substitutes for leaded solders from a mechanical/microstructural properties view. - Abstract: As increasing worldwide demand for portable consumer electronics drives development of smaller, faster, more powerful electronic devices, components in these devices must become smaller, more precise, and more robust. Often, failure of these devices comes as a result of failure of the package (i.e. when a mobile phone is dropped) and specifically comes as a result of failure of solder interconnects. As a result, stronger more reliable solder materials are needed. In this paper, the constitutive responses of three solder materials (Sn63Pb37, Sn62Pb36Ag2, and Sn96.5Ag3Cu0.5) are analyzed as a function of temperature (−196 °C to 60 °C) and strain rate (10 −3 to >10 3 s −1 ). The lead-free Sn96.5Ag3Cu0.5 possessed the highest yield stress of the three solders at all tested strain rates and temperatures, and all solder microstructures which displayed a mechanical response that was sensitive to temperature exhibited grain coarsening with increasing plastic strain, even at room temperature.

  7. The constitutive response of three solder materials

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Bergquist, Alejandro G., E-mail: alexpb@lanl.gov [Materials Science and Technology Division, Los Alamos National Laboratory, Mail Stop G755, Los Alamos, NM 87545 (United States); Cao Fang [Exxon Mobil Research and Engineering Company, Annadale, NJ 08801 (United States); Perez-Bergquist, Sara J.; Lopez, Mike F.; Trujillo, Carl P.; Cerreta, Ellen K.; Gray, George T. [Materials Science and Technology Division, Los Alamos National Laboratory, Mail Stop G755, Los Alamos, NM 87545 (United States)

    2012-05-25

    Highlights: Black-Right-Pointing-Pointer The full constitutive response of three solder materials. Black-Right-Pointing-Pointer Test temperatures from -196 Degree-Sign C to 60 Degree-Sign C and strain rates from 10{sup -3} to >10{sup 3} s{sup -1}. Black-Right-Pointing-Pointer Substitutes for leaded solders from a mechanical/microstructural properties view. - Abstract: As increasing worldwide demand for portable consumer electronics drives development of smaller, faster, more powerful electronic devices, components in these devices must become smaller, more precise, and more robust. Often, failure of these devices comes as a result of failure of the package (i.e. when a mobile phone is dropped) and specifically comes as a result of failure of solder interconnects. As a result, stronger more reliable solder materials are needed. In this paper, the constitutive responses of three solder materials (Sn63Pb37, Sn62Pb36Ag2, and Sn96.5Ag3Cu0.5) are analyzed as a function of temperature (-196 Degree-Sign C to 60 Degree-Sign C) and strain rate (10{sup -3} to >10{sup 3} s{sup -1}). The lead-free Sn96.5Ag3Cu0.5 possessed the highest yield stress of the three solders at all tested strain rates and temperatures, and all solder microstructures which displayed a mechanical response that was sensitive to temperature exhibited grain coarsening with increasing plastic strain, even at room temperature.

  8. Application of electronic speckle-pattern interferometry to measure in-plane thermal displacement in flip-chip packages

    International Nuclear Information System (INIS)

    Lee, Baik-Woo; Jang, Woosoon; Kim, Dong-Won; Jeong, Jeung-hyun; Nah, Jae-Woong; Paik, Kyung-Wook; Kwon, Dongil

    2004-01-01

    Electronic speckle-pattern interferometry (ESPI) was applied for noncontact, real-time evaluation of thermal deformation in a flip-chip package. The spatial resolution of ESPI was increased to submicron scale by magnifying the areas studied in order to measure the deformation of such small-scale components as the solder in the flip-chip package. Thermal deformation in the horizontal and vertical directions around the solder joints was measured as two-dimensional mappings during heating from 25 to 125 deg. C. ESPI was successful in obtaining information on the complicated deformation field around the solder joints. Furthermore, the shear strain could also be calculated using the measured thermal deformation around each solder joint. The applicability of ESPI to flip-chip packages was verified by comparing the ESPI results with those of finite-element analysis (FEA)

  9. Au–Sn bonding material for the assembly of power integrated circuit module

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Z.X.; Li, C.C. [Department of Materials Science & Engineering, National Taiwan University, Taipei, Taiwan (China); Liao, L.L.; Liu, C.K. [Electronic and Optoelectronics Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan (China); Kao, C.R., E-mail: crkao@ntu.edu.tw [Department of Materials Science & Engineering, National Taiwan University, Taipei, Taiwan (China)

    2016-06-25

    Insulated gate bipolar transistor (IGBT) chips are the key components in high-temperature power electronic modules, which have to efficiently convert electricity between direct and alternating current. In this study, the eutectic Au–Sn (20 wt.% Sn) is successfully used to assemble IGBT chips and direct-bond-copper substrates by using solid liquid interdiffusion (SLID) bonding. During subsequent isothermal aging at 150, 200, and 240 °C, the microstructure evolution and growth kinetics of intermetallic compounds are investigated. Excellent thermal stability and mechanical strength are observed. It is concluded that the eutectic Au–Sn solder is ideal to assemble high-temperature IGBT by using the SLID process. - Highlights: • Au–20Sn serves as a promising bonding material for IGBT operating at T < 519 °C. • The Au–20Sn reacted with Ni to form (Ni,Au){sub 3}Sn{sub 2}/(Au{sub 5}Sn + AuSn)/(Ni,Au){sub 3}Sn{sub 2}. • Once the AuSn was nearly exhausted, the whole joint could withstand higher temperatures. • A cost-effective way for long-term operations at high temperature.

  10. Commentary: Photothermal effects of laser tissue soldering

    International Nuclear Information System (INIS)

    Menovsky, T.; Beek, J.F.; Gemert, M.J.C. van

    1999-01-01

    freezing and thawing induces extracellular and intracellular damage. The study is methodologically sound, and the findings in agreement with those of previous studies, i.e. increasing the concentration of the solder results in a greater tensile strength of the bonded tissue and the higher the tissue temperature the greater the thermal damage. As proteins are believed to be the primary component of the welding process, topical applied proteins, used as solders, may provide the necessary amount of protein for welding and result in a greater tensile strength (Poppas et al 1992). A surprising finding is that no colour changes were observed at the irradiances producing optimal tensile strength (corresponding to a temperature of 85 deg. C), as it is above the denaturisation temperature of proteins and logically would be expected to result in some colour changes. Availability and cost are the biggest obstacles to the widespread use of lasers in tissue welding. Most lasers are not equipped with a stable milliwatt mode and/or a micromanipulator. Sutures, on the contrary, are cheap, reliable and always readily available. From a technical point of view, elements of the laser welding technique are unfamiliar to most surgeons. Therefore, acquisition of technical skills and handling of the laser is essential in a laboratory set-up before proceeding to the clinic. For repair of tissues in humans, placement of sutures seems to be mandatory to facilitate manipulation of the tissue during laser irradiation and to lower the risk of post-operative dehiscence. To use the laser only to avoid the placement of extra sutures (and thus proceeding to standard suture repair) seems, at present, unjustified as many studies have failed to show significant results in favour of laser welding. The end point in tissue welding is, at the moment, based on visual changes of the tissue and the surgeon must 'see and feel' whether the welding is complete. It is important that many investigations continue in the

  11. Thermomechanical fatigue life prediction for several solders

    Science.gov (United States)

    Wen, Shengmin

    Since solder connections operate at high homologous temperature, solders are high temperature materials. This feature makes their mechanical behavior and fatigue phenomena unique. Based on experimental findings, a physical damage mechanism is introduced for solders. The mechanism views the damage process as a series of independent local damage events characterized by the failure of individual grains, while the structural damage is the eventual percolation result of such local events. Fine's dislocation energy density concept and Mura's microcrack initiation theory are adopted to derive the fatigue formula for an individual grain. A physical damage metric is introduced to describe the material with damage. A unified creep and plasticity constitutive model is adopted to simulate the mechanical behavior of solders. The model is cast into a continuum damage mechanics framework to simulate material with damage. The model gives good agreement with the experimental results of 96.5Pb-3.5Sn and 96.5Sn-3.5Ag solders under uniaxial strain-controlled cyclic loading. The model is convenient for implementation into commercial computational packages. Also presented is a fatigue theory with its failure criterion for solders based on physical damage mechanism. By introducing grain orientation into the fatigue formula, an m-N curve (m is Schmid factor) at constant loading condition is suggested for fatigue of grains with different orientations. A solder structure is defined as fatigued when the damage metric reaches a critical threshold, since at this threshold the failed grains may form a cluster and percolate through the structure according to percolation theory. Fatigue data of 96.5Pb-3.5Sn solder bulk specimens under various uniaxial tension tests were analyzed. Results show that the theory gives consistent predictions under broad conditions, while inelastic strain theory does not. The theory is anisotropic with no size limitation to its application, which could be suitable for

  12. High temperature soldering of graphite

    International Nuclear Information System (INIS)

    Anikin, L.T.; Kravetskij, G.A.; Dergunova, V.S.

    1977-01-01

    The effect is studied of the brazing temperature on the strength of the brazed joint of graphite materials. In one case, iron and nickel are used as solder, and in another, molybdenum. The contact heating of the iron and nickel with the graphite has been studied in the temperature range of 1400-2400 ged C, and molybdenum, 2200-2600 deg C. The quality of the joints has been judged by the tensile strength at temperatures of 2500-2800 deg C and by the microstructure. An investigation into the kinetics of carbon dissolution in molten iron has shown that the failure of the graphite in contact with the iron melt is due to the incorporation of iron atoms in the interbase planes. The strength of a joint formed with the participation of the vapour-gas phase is 2.5 times higher than that of a joint obtained by graphite recrystallization through the carbon-containing metal melt. The critical temperatures are determined of graphite brazing with nickel, iron, and molybdenum interlayers, which sharply increase the strength of the brazed joint as a result of the formation of a vapour-gas phase and deposition of fine-crystal carbon

  13. Microstructure evolution and thermomechanical fatigue of solder materials

    NARCIS (Netherlands)

    Matin, M.A.

    2005-01-01

    The microelectronics industry is confronted with the new challenge to produce joints with lead-free solder materials replacing classical tin-lead solders in devices used in many fields (e.g. consumer electronics, road transport, aviation, space-crafts, telecommunication). In service, solder

  14. Nanoconstruction by welding individual metallic nanowires together using nanoscale solder

    International Nuclear Information System (INIS)

    Peng, Y; Inkson, B J; Cullis, A G

    2010-01-01

    This work presents a new bottom-up nanowelding technique enabling building blocks to be assembled and welded together into complex 3D nanostructures using nanovolumes of metal solder. The building blocks of gold nanowires, (Co 72 Pt 28 /Pt) n multilayer nanowires, and nanosolder Sn 99 Au 1 alloy nanowires were successfully fabricated by a template technique. Individual metallic nanowires were picked up and assembled together. Conductive nanocircuits were then welded together using similar or dissimilar nanosolder material. At the weld sites, nanoscale volumes of a chosen metal are deposited using nanosolder of a sacrificial nanowire, which ensures that the nanoobjects to be bonded retain their structural integrity. The whole nanowelding process is clean, controllable and reliable, and ensures both mechanically strong and electrically conductive contacts.

  15. A novel method for direct solder bump pull testing using lead-free solders

    Science.gov (United States)

    Turner, Gregory Alan

    This thesis focuses on the design, fabrication, and evaluation of a new method for testing the adhesion strength of lead-free solders, named the Isotraction Bump Pull method (IBP). In order to develop a direct solder joint-strength testing method that did not require customization for different solder types, bump sizes, specific equipment, or trial-and-error, a combination of two widely used and accepted standards was created. First, solder bumps were made from three types of lead free solder were generated on untreated copper PCB substrates using an in-house fabricated solder bump-on-demand generator, Following this, the newly developed method made use of a polymer epoxy to encapsulate the solder bumps that could then be tested under tension using a high precision universal vertical load machine. The tests produced repeatable and predictable results for each of the three alloys tested that were in agreement with the relative behavior of the same alloys using other testing methods in the literature. The median peak stress at failure for the three solders tested were 2020.52 psi, 940.57 psi, and 2781.0 psi, and were within one standard deviation of the of all data collected for each solder. The assumptions in this work that brittle fracture occurred through the Intermetallic Compound layer (IMC) were validated with the use of Energy-Dispersive X-Ray Spectrometry and high magnification of the fractured surface of both newly exposed sides of the test specimens. Following this, an examination of the process to apply the results from the tensile tests into standard material science equations for the fracture of the systems was performed..

  16. Interface between Sn-Sb-Cu solder and copper substrate

    Energy Technology Data Exchange (ETDEWEB)

    Sebo, P., E-mail: Pavel.Sebo@savba.sk [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, 831 02 Bratislava 3 (Slovakia); Svec, P. [Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava 45 (Slovakia); Faculty of Materials Science and Technology, Slovak University of Technology, J. Bottu 25, 917 24 Trnava (Slovakia); Janickovic, D.; Illekova, E. [Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava 45 (Slovakia); Plevachuk, Yu. [Ivan Franko National University, Department of Metal Physics, 79005 Lviv (Ukraine)

    2011-07-15

    Highlights: {yields} New lead-free solder materials based on Sn-Sb-Cu were designed and prepared. {yields} Melting and solidification temperatures of the solders have been determined. {yields} Cu-substrate/solder interaction has been analyzed and quantified. {yields} Phases formed at the solder-substrate interface have been identified. {yields} Composition and soldering atmospheres were correlated with joint strength. - Abstract: Influence of antimony and copper in Sn-Sb-Cu solder on the melting and solidification temperatures and on the microstructure of the interface between the solder and copper substrate after wetting the substrate at 623 K for 1800 s were studied. Microstructure of the interface between the solder and copper substrates in Cu-solder-Cu joints prepared at the same temperature for 1800 s was observed and shear strength of the joints was measured. Influence of the atmosphere - air with the flux and deoxidising N{sub 2} + 10H{sub 2} gas - was taken into account. Thermal stability and microstructure were studied by differential scanning calorimetry (DSC), light microscopy, scanning electron microscopy (SEM) with energy-dispersive spectrometry (EDS) and X-ray diffraction (XRD). Melting and solidification temperatures of the solders were determined. An interfacial transition zone was formed by diffusion reaction between solid copper and liquid solder. At the interface Cu{sub 3}Sn and Cu{sub 6}Sn{sub 5} phases arise. Cu{sub 3}Sn is adjacent to the Cu substrate and its thickness decreases with increasing the amount of copper in solder. Scallop Cu{sub 6}Sn{sub 5} phase is formed also inside the solder drop. The solid solution Sn(Sb) and SbSn phase compose the interior of the solder drop. Shear strength of the joints measured by push-off method decreases with increasing Sb concentration. Copper in the solder shows even bigger negative effect on the strength.

  17. A Hodge dual for soldered bundles

    International Nuclear Information System (INIS)

    Lucas, Tiago Gribl; Pereira, J G

    2009-01-01

    In order to account for all possible contractions allowed by the presence of the solder form, a generalized Hodge dual is defined for the case of soldered bundles. Although for curvature the generalized dual coincides with the usual one, for torsion it gives a completely new dual definition. Starting from the standard form of a gauge Lagrangian for the translation group, the generalized Hodge dual yields precisely the Lagrangian of the teleparallel equivalent of general relativity, and consequently also the Einstein-Hilbert Lagrangian of general relativity

  18. Visual detection of defects in solder joints

    Science.gov (United States)

    Blaignan, V. B.; Bourbakis, Nikolaos G.; Moghaddamzadeh, Ali; Yfantis, Evangelos A.

    1995-03-01

    The automatic, real-time visual acquisition and inspection of VLSI boards requires the use of machine vision and artificial intelligence methodologies in a new `frame' for the achievement of better results regarding efficiency, products quality and automated service. In this paper the visual detection and classification of different types of defects on solder joints in PC boards is presented by combining several image processing methods, such as smoothing, segmentation, edge detection, contour extraction and shape analysis. The results of this paper are based on simulated solder defects and a real one.

  19. Laser solder welding of articular cartilage: tensile strength and chondrocyte viability.

    Science.gov (United States)

    Züger, B J; Ott, B; Mainil-Varlet, P; Schaffner, T; Clémence, J F; Weber, H P; Frenz, M

    2001-01-01

    The surgical treatment of full-thickness cartilage defects in the knee joint remains a therapeutic challenge. Recently, new techniques for articular cartilage transplantation, such as mosaicplasty, have become available for cartilage repair. The long-term success of these techniques, however, depends not only on the chondrocyte viability but also on a lateral integration of the implant. The goal of this study was to evaluate the feasibility of cartilage welding by using albumin solder that was dye-enhanced to allow coagulation with 808-nm laser diode irradiation. Conventional histology of light microscopy was compared with a viability staining to precisely determine the extent of thermal damage after laser welding. Indocyanine green (ICG) enhanced albumin solder (25% albumin, 0.5% HA, 0.1% ICG) was used for articular cartilage welding. For coagulation, the solder was irradiated through the cartilage implant by 808-nm laser light and the tensile strength of the weld was measured. Viability staining revealed a thermal damage of typically 500 m in depth at an irradiance of approximately 10 W/cm(2) for 8 seconds, whereas conventional histologies showed only half of the extent found by the viability test. Heat-bath investigations revealed a threshold temperature of minimum 54 degrees C for thermal damage of chondrocytes. Efficient cartilage bonding was obtained by using bovine albumin solder as adhesive. Maximum tensile strength of more than 10 N/cm(2) was achieved. Viability tests revealed that the thermal damage is much greater (up to twice) than expected after light microscopic characterization. This study shows the feasibility to strongly laser weld cartilage on cartilage by use of a dye-enhanced albumin solder. Possibilities to reduce the range of damage are suggested. Copyright 2001 Wiley-Liss, Inc.

  20. Laser assisted soldering: microdroplet accumulation with a microjet device.

    Science.gov (United States)

    Chan, E K; Lu, Q; Bell, B; Motamedi, M; Frederickson, C; Brown, D T; Kovach, I S; Welch, A J

    1998-01-01

    We investigated the feasibility of a microjet to dispense protein solder for laser assisted soldering. Successive micro solder droplets were deposited on rat dermis and bovine intima specimens. Fixed laser exposure was synchronized with the jetting of each droplet. After photocoagulation, each specimen was cut into two halves at the center of solder coagulum. One half was fixed immediately, while the other half was soaked in phosphate-buffered saline for a designated hydration period before fixation (1 hour, 1, 2, and 7 days). After each hydration period, all tissue specimens were prepared for scanning electron microscopy (SEM). Stable solder coagulum was created by successive photocoagulation of microdroplets even after the soldered tissue exposed to 1 week of hydration. This preliminary study suggested that tissue soldering with successive microdroplets is feasible even with fixed laser parameters without active feedback control.

  1. Diode Lasers used in Plastic Welding and Selective Laser Soldering - Applications and Products

    Science.gov (United States)

    Reinl, S.

    Aside from conventional welding methods, laser welding of plastics has established itself as a proven bonding method. The component-conserving and clean process offers numerous advantages and enables welding of sensitive assemblies in automotive, electronic, medical, human care, food packaging and consumer electronics markets. Diode lasers are established since years within plastic welding applications. Also, soft soldering using laser radiation is becoming more and more significant in the field of direct diode laser applications. Fast power controllability combined with a contactless temperature measurement to minimize thermal damage make the diode laser an ideal tool for this application. These advantages come in to full effect when soldering of increasingly small parts in temperature sensitive environments is necessary.

  2. Processing and Characterization of NiTi Shape Memory Alloy Particle Reinforced Sn-In Solders

    National Research Council Canada - National Science Library

    Chung, Kohn C

    2006-01-01

    .... In previous work, it was proposed that reinforcement of solder by NiTi shape memory alloy particles to form smart composite solder reduces the inelastic strain of the solder and hence, may enhance...

  3. Electrical characteristics for Sn-Ag-Cu solder bump with Ti/Ni/Cu under-bump metallization after temperature cycling tests

    Science.gov (United States)

    Shih, T. I.; Lin, Y. C.; Duh, J. G.; Hsu, Tom

    2006-10-01

    Lead-free solder bumps have been widely used in current flip-chip technology (FCT) due to environmental issues. Solder joints after temperature cycling tests were employed to investigate the interfacial reaction between the Ti/Ni/Cu under-bump metallization and Sn-Ag-Cu solders. The interfacial morphology and quantitative analysis of the intermetallic compounds (IMCs) were obtained by electron probe microanalysis (EPMA) and field emission electron probe microanalysis (FE-EPMA). Various types of IMCs such as (Cu1-x,Agx)6Sn5, (Cu1-y,Agy)3Sn, and (Ag1-z,Cuz)3Sn were observed. In addition to conventional I-V measurements by a special sample preparation technique, a scanning electron microscope (SEM) internal probing system was introduced to evaluate the electrical characteristics in the IMCs after various test conditions. The electrical data would be correlated to microstructural evolution due to the interfacial reaction between the solder and under-bump metallurgy (UBM). This study demonstrated the successful employment of an internal nanoprobing approach, which would help further understanding of the electrical behavior within an IMC layer in the solder/UBM assembly.

  4. Chemical wiring and soldering toward all-molecule electronic circuitry.

    Science.gov (United States)

    Okawa, Yuji; Mandal, Swapan K; Hu, Chunping; Tateyama, Yoshitaka; Goedecker, Stefan; Tsukamoto, Shigeru; Hasegawa, Tsuyoshi; Gimzewski, James K; Aono, Masakazu

    2011-06-01

    Key to single-molecule electronics is connecting functional molecules to each other using conductive nanowires. This involves two issues: how to create conductive nanowires at designated positions, and how to ensure chemical bonding between the nanowires and functional molecules. Here, we present a novel method that solves both issues. Relevant functional molecules are placed on a self-assembled monolayer of diacetylene compound. A probe tip of a scanning tunneling microscope is then positioned on the molecular row of the diacetylene compound to which the functional molecule is adsorbed, and a conductive polydiacetylene nanowire is fabricated by initiating chain polymerization by stimulation with the tip. Since the front edge of chain polymerization necessarily has a reactive chemical species, the created polymer nanowire forms chemical bonding with an encountered molecular element. We name this spontaneous reaction "chemical soldering". First-principles theoretical calculations are used to investigate the structures and electronic properties of the connection. We demonstrate that two conductive polymer nanowires are connected to a single phthalocyanine molecule. A resonant tunneling diode formed by this method is discussed. © 2011 American Chemical Society

  5. Effect of Solder Flux Residues on Corrosion of Electronics

    DEFF Research Database (Denmark)

    Hansen, Kirsten Stentoft; Jellesen, Morten Stendahl; Møller, Per

    2009-01-01

    Flux from ‘No Clean’ solder processes can cause reliability problems in the field due to aggressive residues, which may be electrical conducting or corrosive in humid environments. The solder temperature during a wave solder process is of great importance to the amount of residues left on a PCBA...... testing and use in the field, consequences and recommendations are given. Failures, caused by harsh[1] customer environments, are not covered in this paper....

  6. Mechanical properties of soldered joints of niobium base alloys

    International Nuclear Information System (INIS)

    Grishin, V.L.

    1980-01-01

    Mechanical properties of soldered joints of niobium alloys widely distributed in industry: VN3, VN4, VN5A, VN5AE, VN5AEP etc., 0.6-1.2 mm thick are investigated. It is found out that the usage of zirconium-vanadium, titanium-tantalum solders for welding niobium base alloys permits to obtain soldered joints with satisfactory mechanical properties at elevated temperatures

  7. Tin-silver and tin-copper alloys for capillarity joining-soft soldering-of copper piping

    International Nuclear Information System (INIS)

    Duran, J.; Amo, J. M.; Duran, C. M.

    2001-01-01

    It is studied the influence of the type of alloy used as filling material on the defects of the soldering joints in copper piping installations, which induce the fluid leak of the systems. The different eutectic temperatures and solidus-liquidus ranges of these alloys, require the setting of the soldering heat input in each case to obtain the suitable capillarity features and alloying temperatures to achieve for the correct formation of the bonding. Most defects in the joints are demonstrated to be generated by bad dossification of thermal inputs, which led depending on the filler alloy used to variations in its fluidity that may produce penetration failures in the bonds or insufficient consistency for the filling of the joints. (Author) 7 refs

  8. Effects of PCB Pad Metal Finishes on the Cu-Pillar/Sn-Ag Micro Bump Joint Reliability of Chip-on-Board (COB) Assembly

    Science.gov (United States)

    Kim, Youngsoon; Lee, Seyong; Shin, Ji-won; Paik, Kyung-Wook

    2016-06-01

    While solder bumps have been used as the bump structure to form the interconnection during the last few decades, the continuing scaling down of devices has led to a change in the bump structure to Cu-pillar/Sn-Ag micro-bumps. Cu-pillar/Sn-Ag micro-bump interconnections differ from conventional solder bump interconnections in terms of their assembly processing and reliability. A thermo-compression bonding method with pre-applied b-stage non-conductive films has been adopted to form solder joints between Cu pillar/Sn-Ag micro bumps and printed circuit board vehicles, using various pad metal finishes. As a result, various interfacial inter-metallic compounds (IMCs) reactions and stress concentrations occur at the Cu pillar/Sn-Ag micro bumps joints. Therefore, it is necessary to investigate the influence of pad metal finishes on the structural reliability of fine pitch Cu pillar/Sn-Ag micro bumps flip chip packaging. In this study, four different pad surface finishes (Thin Ni ENEPIG, OSP, ENEPIG, ENIG) were evaluated in terms of their interconnection reliability by thermal cycle (T/C) test up to 2000 cycles at temperatures ranging from -55°C to 125°C and high-temperature storage test up to 1000 h at 150°C. The contact resistances of the Cu pillar/Sn-Ag micro bump showed significant differences after the T/C reliability test in the following order: thin Ni ENEPIG > OSP > ENEPIG where the thin Ni ENEPIG pad metal finish provided the best Cu pillar/Sn-Ag micro bump interconnection in terms of bump joint reliability. Various IMCs formed between the bump joint areas can account for the main failure mechanism.

  9. Evaluation on the characteristics of tin-silver-bismuth solder

    Science.gov (United States)

    Xia, Z.; Shi, Y.; Chen, Z.

    2002-02-01

    Tin-silver-bismuth solder is characterized by its lower melting point, good wetting behavior, and good mechanical property for which it is expected to be a new lead-free solder to replace tin-lead solder. In this article, Sn-3.33Ag-4.83Bi solder was investigated concerning its physical, spreading, and mechanical properties under specific conditions. Cooling curves and DSC results showed that it was close to eutectic composition (m.p. 210° 212 °C). Coefficiency of thermal expansion (CTE) of this solder, between that of PCBs and copper substrates, was beneficial to alleviate the thermal mismatch of the substrates. It was also a good electrical and thermal conductor. Using a rosin-based, mildly activated (RMA) flux, a spreading test indicated that SnAgBi solder paste had good solderability. Meanwhile, the solder had high tensile strength and fracture energy. Its fracture mechanism was a mixture of ductile and brittle fracture morphology. The metallographic and EDAX analyses indicated that it was composed of a tin-based solid solution and some intermetallic compound (IMC) that could strengthen the substrate. However, these large needle-like IMCs would cut the substrate and this resulted in the decreasing of the toughness of the solder.

  10. Reliability Study of Solder Paste Alloy for the Improvement of Solder Joint at Surface Mount Fine-Pitch Components

    Directory of Open Access Journals (Sweden)

    Mohd Nizam Ab. Rahman

    2014-12-01

    Full Text Available The significant increase in metal costs has forced the electronics industry to provide new materials and methods to reduce costs, while maintaining customers’ high-quality expectations. This paper considers the problem of most electronic industries in reducing costly materials, by introducing a solder paste with alloy composition tin 98.3%, silver 0.3%, and copper 0.7%, used for the construction of the surface mount fine-pitch component on a Printing Wiring Board (PWB. The reliability of the solder joint between electronic components and PWB is evaluated through the dynamic characteristic test, thermal shock test, and Taguchi method after the printing process. After experimenting with the dynamic characteristic test and thermal shock test with 20 boards, the solder paste was still able to provide a high-quality solder joint. In particular, the Taguchi method is used to determine the optimal control parameters and noise factors of the Solder Printer (SP machine, that affects solder volume and solder height. The control parameters include table separation distance, squeegee speed, squeegee pressure, and table speed of the SP machine. The result shows that the most significant parameter for the solder volume is squeegee pressure (2.0 mm, and the solder height is the table speed of the SP machine (2.5 mm/s.

  11. Surface Tension Directed Fluidic Self-Assembly of Semiconductor Chips across Length Scales and Material Boundaries

    Directory of Open Access Journals (Sweden)

    Shantonu Biswas

    2016-03-01

    Full Text Available This publication provides an overview and discusses some challenges of surface tension directed fluidic self-assembly of semiconductor chips which are transported in a liquid medium. The discussion is limited to surface tension directed self-assembly where the capture, alignment, and electrical connection process is driven by the surface free energy of molten solder bumps where the authors have made a contribution. The general context is to develop a massively parallel and scalable assembly process to overcome some of the limitations of current robotic pick and place and serial wire bonding concepts. The following parts will be discussed: (2 Single-step assembly of LED arrays containing a repetition of a single component type; (3 Multi-step assembly of more than one component type adding a sequence and geometrical shape confinement to the basic concept to build more complex structures; demonstrators contain (3.1 self-packaging surface mount devices, and (3.2 multi-chip assemblies with unique angular orientation. Subsequently, measures are discussed (4 to enable the assembly of microscopic chips (10 μm–1 mm; a different transport method is introduced; demonstrators include the assembly of photovoltaic modules containing microscopic silicon tiles. Finally, (5 the extension to enable large area assembly is presented; a first reel-to-reel assembly machine is realized; the machine is applied to the field of solid state lighting and the emerging field of stretchable electronics which requires the assembly and electrical connection of semiconductor devices over exceedingly large area substrates.

  12. Laser-activated protein solder for peripheral nerve repair

    Science.gov (United States)

    Trickett, Rodney I.; Lauto, Antonio; Dawes, Judith M.; Owen, Earl R.

    1995-05-01

    A 100 micrometers core optical fiber-coupled 75 mW diode laser operating at a wavelength of 800 nm has been used in conjunction with a protein solder to stripe weld severed rat tibial nerves, reducing the long operating time required for microsurgical nerve repair. Welding is produced by selective laser denaturation of the albumin based solder which contains the dye indocyanine green. Operating time for laser soldering was 10 +/- 5 min. (n equals 20) compared to 23 +/- 9 min. (n equals 10) for microsuturing. The laser solder technique resulted in patent welds with a tensile strength of 15 +/- 5 g, while microsutured nerves had a tensile strength of 40 +/- 10 g. Histopathology of the laser soldered nerves, conducted immediately after surgery, displayed solder adhesion to the outer membrane with minimal damage to the inner axons of the nerves. An in vivo study is under way comparing laser solder repaired tibial nerves to conventional microsuture repair. At the time of submission 15 laser soldered nerves and 7 sutured nerves were characterized at 3 months and showed successful regeneration with compound muscle action potentials of 27 +/- 8 mV and 29 +/- 8 mW respectively. A faster, less damaging and long lasting laser based anastomotic technique is presented.

  13. Soldering of copper-clad niobium--titanium superconductor composite

    International Nuclear Information System (INIS)

    Moorhead, A.J.; Woodhouse, J.J.; Easton, D.S.

    1977-04-01

    When superconductivity is applied to various electrical devices, the joining of the superconducting material and the performance of the joints are generally crucial to the successful operation of the system. Although many techniques are being considered for joining composite superconductors, soldering is the most common. We determined the wetting and flow behavior of various solder and flux combinations on a copper-clad Nb-Ti composite, developed equipment and techniques for soldering and inspection of lap joints, and determined the shear strength of joints at temperatures down to -269 0 C (4 0 K). We studied 15 solders and 17 commercial and experimental fluxes in the wettability and flow tests. A resistance unit was built for soldering test specimens. A series of samples soldered with 80 Pb-20 Sn, 83 Pb-15 Sn-2 Sb, 97.5 Pb-1.5 Ag-1 Sn, 80 In-15 Pb-5 Ag, or 25 In-37.5 Pb-37.5 Sn (wt percent) was inspected by three nondestructive techniques. Through-transmission ultrasound gave the best correlation with nonbond areas revealed in peel tests. Single-lap shear specimens soldered with 97.5 Pb-1.5 Ag-1 Sn had the highest strength (10.44 ksi, 72 MPa) and total elongation (0.074 in., 1.88 mm) at -269 0 C (4 0 K) of four solders tested

  14. Integration of environmentally compatible soldering technologies for waste minimization

    International Nuclear Information System (INIS)

    Hosking, F.M.

    1992-01-01

    There has been a concentrated effort throughout the international microelectronics industry to phase out chlorofluorocarbon (CFC) materials and alleviate the serious problem of ozone depletion created by the release of CFCS. The development of more environmentally compatible manufacturing technologies is the cornerstone of this effort. Alternative materials and processes for cleaning and soldering have received special attention. Electronic. soldering typically utilizes rosin-based fluxes to promote solder wettability. Flux residues must be removed from the soldered parts when high product reliability is essential. Halogenated or CFC solvents have been the principle chemicals used to clean the residues. With the accelerated push to eliminate CFCs in the US by 1995, CFC-free solvents, aqueous-based cleaning, water soluble or ''no clean'' fluxes, and fluxless soldering technologies are being developed and quickly integrated into manufacturing practice. Sandia's Center for Solder Science and Technology has been ch g a variety of fluxless and alternative soldering technologies for DOE's waste minimization program. The work has focused on controlled atmosphere, laser, and ultrasonic fluxless soldering, protective metallic and organic coatings, and fluxes which have water soluble or low solids-based chemistries. With the increasing concern that Pb will also be banned from electronic soldering, Sandia has been characterizing the wetting, aging, and mechanical properties of Pb-fire solder alloys. The progress of these integrated studies will be discussed. Their impact on environmentally compatible manufacturing will be emphasized. Since there is no universal solution to the various environmental, safety, and health issues which currently face industry, the proposed technologies offer several complementary materials and processing options from which one can choose

  15. Microstructurally Adaptive Constitutive Relations and Reliability Assessment Protocols for Lead Free Solder

    Science.gov (United States)

    2015-05-05

    under bump metallurgy and solder joint geometry on Sn grain morphology in Pb free solder joints were examined. SnAgCu solder joints were examined for...free solder interconnects”, Sci. Technol. Weld . Join. 13, 732 (2008). [3.25] Terashima, S., Takahama, K., Nozaki, M., and Tanaka, M. Recrystallization

  16. Flip chip assembly of thinned chips for hybrid pixel detector applications

    International Nuclear Information System (INIS)

    Fritzsch, T; Zoschke, K; Rothermund, M; Oppermann, H; Woehrmann, M; Ehrmann, O; Lang, K D; Huegging, F

    2014-01-01

    There is a steady trend to ultra-thin microelectronic devices. Especially for future particle detector systems a reduced readout chip thickness is required to limit the loss of tracking precision due to scattering. The reduction of silicon thickness is performed at wafer level in a two-step thinning process. To minimize the risk of wafer breakage the thinned wafer needs to be handled by a carrier during the whole process chain of wafer bumping. Another key process is the flip chip assembly of thinned readout chips onto thin sensor tiles. Besides the prevention of silicon breakage the minimization of chip warpage is one additional task for a high yield and reliable flip chip process. A new technology using glass carrier wafer will be described in detail. The main advantage of this technology is the combination of a carrier support during wafer processing and the chip support during flip chip assembly. For that a glass wafer is glue-bonded onto the backside of the thinned readout chip wafer. After the bump deposition process the glass-readout chip stack is diced in one step. Finally the glass carrier chip is released by laser illumination after flip chip assembly of the readout chip onto sensor tile. The results of the flip chip assembly process development for the ATLAS IBL upgrade are described more in detail. The new ATLAS FEI4B chip with a size of 20 × 19 mm 2 is flip chip bonded with a thickness of only 150 μm, but the capability of this technology has been demonstrated on hybrid modules with a reduced readout chip thickness of down to 50 μm which is a major step for ultra-thin electronic systems

  17. Fundamental study of microelectronic chip response under laser ultrasonic-interferometric inspection using C-scan method

    Science.gov (United States)

    Yang, Lei; Gong, Jie; Ume, I. Charles

    2014-02-01

    In modern surface mount packaging technologies, such as flip chips, chip scale packages, and ball grid arrays(BGA), chips are attached to the substrates/printed wiring board (PWB) using solder bump interconnections. The quality of solder bumps between the chips and the substrate/board is difficult to inspect. Laser ultrasonic-interferometric technique was proved to be a promising approach for solder bump inspection because of its noncontact and nondestructive characteristics. Different indicators extracted from received signals have been used to predict the potential defects, such as correlation coefficient, error ratio, frequency shifting, etc. However, the fundamental understanding of the chip behavior under laser ultrasonic inspection is still missing. Specifically, it is not sure whether the laser interferometer detected out-of-plane displacements were due to wave propagation or structural vibration when the chip was excited by pulsed laser. Plus, it is found that the received signals are chip dependent. Both challenges impede the interpretation of acquired signals. In this paper, a C-scan method was proposed to study the underlying phenomenon during laser ultrasonic inspection. The full chip was inspected. The response of the chip under laser excitation was visualized in a movie resulted from acquired signals. Specifically, a BGA chip was investigated to demonstrate the effectiveness of this method. By characterizing signals using discrete wavelet transform(DWT), both ultrasonic wave propagation and vibration were observed. Separation of them was successfully achieved using ideal band-pass filter and visualized in resultant movies, too. The observed ultrasonic waves were characterized and their respective speeds were measured by applying 2-D FFT. The C-scan method, combined with different digital signal processing techniques, was proved to be an very effective methodology to learn the behavior of chips under laser excitation. This general procedure can be

  18. Characterization of lead-free solders for electronic packaging

    Science.gov (United States)

    Ma, Hongtao

    The characterization of lead-free solders, especially after isothermal aging, is very important in order to accurately predict the reliability of solder joints. However, due to lack of experimental testing standards and the high homologous temperature of solder alloys (Th > 0.5T m even at room temperature), there are very large discrepancies in both the tensile and creep properties provided in current databases for both lead-free and Sn-Pb solder alloys. In this research, mechanical measurements of isothermal aging effects and the resulting changes in the materials behavior of lead-free solders were performed. A novel specimen preparation procedure was developed where the solder uniaxial test specimens are formed in high precision rectangular cross-section glass tubes using a vacuum suction process. Using specimens fabricated with the developed procedure, isothermal aging effects and viscoplastic material behavior evolution have been characterized for 95.5Sn-4.0Ag-0.5Cu (SAC405) and 96.5Sn-3.0Ag-0.5Cu (SAC305) lead-free solders, which are commonly used as the solder ball alloy in lead-free BGAs and other components. Analogous tests were performed with 63Sn-37Pb eutectic solder samples for comparison purposes. Up to 40% reduction in tensile strength was observed for water quenched specimens after two months of aging at room temperature. Creep deformation also increased dramatically with increasing aging durations. Microstructural changes during room temperature aging were also observed and recorded for the solder alloys and correlated with the observed mechanical behavior changes. Aging effects at elevated temperatures for up to 6 months were also investigated. Thermal aging caused significant tensile strength loss and deterioration of creep deformation. The thermal aging results also showed that after an initial tensile strength drop, the Sn-Pb eutectic solder reached a relatively stable stage after 200 hours of aging. However, for SAC alloy, both the tensile and

  19. Soldering formalism in noncommutative field theory: a brief note

    International Nuclear Information System (INIS)

    Ghosh, Subir

    2004-01-01

    In this Letter, I develop the soldering formalism in a new domain--the noncommutative planar field theories. The soldering mechanism fuses two distinct theories showing opposite or complimentary properties of some symmetry, taking into account the interference effects. The above mentioned symmetry is hidden in the composite (or soldered) theory. In the present work it is shown that a pair of noncommutative Maxwell-Chern-Simons theories, having opposite signs in their respective topological terms, can be consistently soldered to yield the Proca model (Maxwell theory with a mass term) with corrections that are at least quadratic in the noncommutativity parameter. We further argue that this model can be thought of as the noncommutative generalization of the Proca theory of ordinary spacetime. It is well known that abelian noncommutative gauge theory bears a close structural similarity with non-abelian gauge theory. This fact is manifested in a non-trivial way if the present Letter is compared with existing literature, where soldering of non-abelian models are discussed. Thus the present work further establishes the robustness of the soldering programme. The subtle role played by gauge invariance (or the lack of it), in the above soldering process, is revealed in an interesting way

  20. Utilization of Pb-free solders in MEMS packaging

    Science.gov (United States)

    Selvaduray, Guna S.

    2003-01-01

    Soldering of components within a package plays an important role in providing electrical interconnection, mechanical integrity and thermal dissipation. MEMS packages present challenges that are more complex than microelectronic packages because they are far more sensitive to shock and vibration and also require precision alignment. Soldering is used at two major levels within a MEMS package: at the die attach level and at the component attach level. Emerging environmental regulations worldwide, notably in Europe and Japan, have targeted the elimination of Pb usage in electronic assemblies, due to the inherent toxicity of Pb. This has provided the driving force for development and deployment of Pb-free solder alloys. A relatively large number of Pb-free solder alloys have been proposed by various researchers and companies. Some of these alloys have also been patented. After several years of research, the solder alloy system that has emerged is based on Sn as a major component. The electronics industry has identified different compositions for different specific uses, such as wave soldering, surface mount reflow, etc. The factors that affect choice of an appropriate Pb-free solder can be divided into two major categories, those related to manufacturing, and those related to long term reliability and performance.

  1. Fatigue and thermal fatigue of Pb-Sn solder joints

    International Nuclear Information System (INIS)

    Frear, D.; Grivas, D.; McCormack, M.; Tribula, D.; Morris, J.W. Jr.

    1987-01-01

    This paper presents a fundamental investigation of the fatigue and thermal fatigue characteristics, with an emphasis on the microstructural development during fatigue, of Sn-Pb solder joints. Fatigue tests were performed in simple shear on both 60Sn-40Pb and 5Sn-95Pb solder joints. Isothermal fatigue tests show increasing fatigue life of 60Sn-40Pb solder joints with decreasing strain and temperature. In contrast, such behavior was not observed in the isothermal fatigue of 5Sn-95Pb solder joints. Thermal fatigue results on 60Sn-40Pb solder cycled between -55 0 C and 125 0 C show that a coarsened region develops in the center of the joint. Both Pb-rich and Sn-rich phases coarsen, and cracks form within these coarsened regions. The failure mode 60Sn-40Pb solder joints in thermal and isothermal fatigue is similar: cracks form intergranularly through the Sn-rich phase or along Sn/Pb interphase boundaries. Extensive cracking is found throughout the 5Sn-95Pb joint for both thermal and isothermal fatigue. In thermal fatigue the 5Sn-95Pb solder joints failed after fewer cycles than 60Sn-40Pb

  2. Adhesive-Bonded Tab Attaches Thermocouples to Titanium

    Science.gov (United States)

    Cook, C. F.

    1982-01-01

    Mechanical strength of titanium-alloy structures that support thermocouples is preserved by first spotwelding thermocouples to titanium tabs and then attaching tabs to titanium with a thermosetting adhesive. In contrast to spot welding, a technique previously used for thermocouples, fatigue strength of the titanium is unaffected by adhesive bonding. Technique is also gentler than soldering or attaching thermocouples with a tap screw.

  3. Assessment of potential solder candidates for high temperature applications

    DEFF Research Database (Denmark)

    pressure to eliminate lead containing materials despite the fact that materials for high Pb containing alloys are currently not affected by any legislations. A tentative assessment was carried out to determine the potential solder candidates for high temperature applications based on the solidification...... criterion, phases predicted in the bulk solder and the thermodynamic stability of chlorides. These promising solder candidates were precisely produced using the hot stage microscope and its respective anodic and cathodic polarization curves were investigated using a micro-electrochemical set up...

  4. Manipulation and soldering of carbon nanotubes using atomic force microscope

    International Nuclear Information System (INIS)

    Kashiwase, Yuta; Ikeda, Takayuki; Oya, Takahide; Ogino, Toshio

    2008-01-01

    Manipulation of carbon nanotubes (CNTs) by an atomic force microscope (AFM) and soldering of CNTs using Fe oxide nanoparticles are described. We succeeded to separate a CNT bundle into two CNTs or CNT bundles, to move the separated CNT to a desirable position, and to bind it to another bundle. For the accurate manipulation, load of the AFM cantilever and frequency of the scan were carefully selected. We soldered two CNTs using an Fe oxide nanoparticle prepared from a ferritin molecule. The adhesion forces between the soldered CNTs were examined by an AFM and it was found that the CNTs were bound, though the binding force was not strong

  5. Effect of soldering techniques and gap distance on tensile strength of soldered Ni-Cr alloy joint.

    Science.gov (United States)

    Lee, Sang-Yeob; Lee, Jong-Hyuk

    2010-12-01

    The present study was intended to evaluate the effect of soldering techniques with infrared ray and gas torch under different gap distances (0.3 mm and 0.5 mm) on the tensile strength and surface porosity formation in Ni-Cr base metal alloy. Thirty five dumbbell shaped Ni-Cr alloy specimens were prepared and assigned to 5 groups according to the soldering method and the gap distance. For the soldering methods, gas torch (G group) and infrared ray (IR group) were compared and each group was subdivided by corresponding gap distance (0.3 mm: G3 and IR3, 0.5 mm: G5, IR5). Specimens of the experimental groups were sectioned in the middle with a diamond disk and embedded in solder blocks according to the predetermined distance. As a control group, 7 specimens were prepared without sectioning or soldering. After the soldering procedure, a tensile strength test was performed using universal testing machine at a crosshead speed 1 mm/min. The proportions of porosity on the fractured surface were calculated on the images acquired through the scanning electronic microscope. Every specimen of G3, G5, IR3 and IR5 was fractured on the solder joint area. However, there was no significant difference between the test groups (P > .05). There was a negative correlation between porosity formation and tensile strength in all the specimens in the test groups (P tensile strength of joints and porosity formations between the gas-oxygen torch soldering and infrared ray soldering technique or between the gap distance of 0.3 mm and 0.5 mm.

  6. Interfacial Reaction of Sn-Ag-Cu Lead-Free Solder Alloy on Cu: A Review

    Directory of Open Access Journals (Sweden)

    Liu Mei Lee

    2013-01-01

    Full Text Available This paper reviews the function and importance of Sn-Ag-Cu solder alloys in electronics industry and the interfacial reaction of Sn-Ag-Cu/Cu solder joint at various solder forms and solder reflow conditions. The Sn-Ag-Cu solder alloys are examined in bulk and in thin film. It then examines the effect of soldering conditions to the formation of intermetallic compounds such as Cu substrate selection, structural phases, morphology evolution, the growth kinetics, temperature and time is also discussed. Sn-Ag-Cu lead-free solder alloys are the most promising candidate for the replacement of Sn-Pb solders in modern microelectronic technology. Sn-Ag-Cu solders could possibly be considered and adapted in miniaturization technologies. Therefore, this paper should be of great interest to a large selection of electronics interconnect materials, reliability, processes, and assembly community.

  7. Strength of joints brazed with two-phase solders

    International Nuclear Information System (INIS)

    Shnyakin, N.S.; Parfenova, L.V.; Ekatova, A.S.; Prilepskaya, I.V.

    1976-01-01

    Dependence of the structure and strength of soldered joints upon a gap size in case of 1Kh18N10T stainless steel soldering with a double-phase solder of Ni-Zn-Cu system is described. Butt and lap joints have been subjected to soldering with gas-flame and induction heating. The optimum conditions of the solder crystallization are determined with wedge-gap samples. The studies show that the character of distribution of a fusible β-phase in metal depends upon a gap size. With gaps up to 0.1 mm the β-phase enriched with a fusible component (zinc) runs as a continuous thin interlayer in the middle of the seam. As a result of zinc evaporation from the β-phase this interlayer becomes internally oxidized. After the sample is broken an oxidized fracture gives one the impression of a poor fusion in the middle part of the joint. The ultimate strength of butt joints is 15-20 kgf/sq.mm. A value of thermal expansion of 1Kh18N10T steel samples, 1-5 mm thick, has been experimentally determined for butt soldering. The elongation of two halves of the sample is measured by an indicator and proved to be 0.89 mm for a 50x50x2 mm sample at a soldering temperature of 1.100 deg C. The paper presents methods for the calculation of an optimal gap value for butt soldering with a local gas-flame and induction heating

  8. Joining technologies for the 1990s: Welding, brazing, soldering, mechanical, explosive, solid-state, adhesive

    Science.gov (United States)

    Buckley, John D. (Editor); Stein, Bland A. (Editor)

    1986-01-01

    A compilation of papers presented in a joint NASA, American Society for Metals, The George Washington University, American Welding Society, and Society of Manufacturing Engineers Conference on Welding, Bonding, and Fastening at Langley Research Center, Hampton, VA, on October 23 to 25, 1984 is given. Papers were presented on technology developed in current research programs relevant to welding, bonding, and fastening of structural materials required in fabricating structures and mechanical systems used in the aerospace, hydrospace, and automotive industries. Topics covered in the conference included equipment, hardware and materials used when welding, brazing, and soldering, mechanical fastening, explosive welding, use of unique selected joining techniques, adhesives bonding, and nondestructive evaluation. A concept of the factory of the future was presented, followed by advanced welding techniques, automated equipment for welding, welding in a cryogenic atmosphere, blind fastening, stress corrosion resistant fasteners, fastening equipment, explosive welding of different configurations and materials, solid-state bonding, electron beam welding, new adhesives, effects of cryogenics on adhesives, and new techniques and equipment for adhesive bonding.

  9. Chips 2020

    CERN Document Server

    2016-01-01

    The release of this second volume of CHIPS 2020 coincides with the 50th anniversary of Moore’s Law, a critical year marked by the end of the nanometer roadmap and by a significantly reduced annual rise in chip performance. At the same time, we are witnessing a data explosion in the Internet, which is consuming 40% more electrical power every year, leading to fears of a major blackout of the Internet by 2020. The messages of the first CHIPS 2020, published in 2012, concerned the realization of quantum steps for improving the energy efficiency of all chip functions. With this second volume, we review these messages and amplify upon the most promising directions: ultra-low-voltage electronics, nanoscale monolithic 3D integration, relevant-data, brain- and human-vision-inspired processing, and energy harvesting for chip autonomy. The team of authors, enlarged by more world leaders in low-power, monolithic 3D, video, and Silicon brains, presents new vistas in nanoelectronics, promising  Moore-like exponential g...

  10. Laser Soldering of Rat Skin Using a Controlled Feedback System

    Directory of Open Access Journals (Sweden)

    Mohammad Sadegh Nourbakhsh

    2009-03-01

    Full Text Available Introduction: Laser tissue soldering using albumin and indocyanine green dye (ICG is an effective technique utilized in various surgical procedures. The purpose of this study was to perform laser soldering of rat skin under a feedback control system and compare the results with those obtained using standard sutures. Material and Methods: Skin incisions were made over eight rats’ dorsa, which were subsequently closed using different wound closure interventions in two groups: (a using a temperature controlled infrared detector or (b by suture. Tensile strengths were measured at 2, 5, 7 and 10 days post-incision. Histological examination was performed at the time of sacrifice. Results: Tensile strength results showed that during the initial days following the incisions, the tensile strengths of the sutured samples were greater than the laser samples. However, 10 days after the incisions, the tensile strengths of the laser soldered incisions were higher than the sutured cuts. Histopathological examination showed a preferred wound healing response in the soldered skin compared with the control samples. The healing indices of the laser soldered repairs (426 were significantly better than the control samples (340.5. Conclusion: Tissue feedback control of temperature and optical changes in laser soldering of skin leads to a higher tensile strength and better histological results and hence this method may be considered as an alternative to standard suturing.

  11. Tensile strength of two soldered alloys (Minalux and Verabond2

    Directory of Open Access Journals (Sweden)

    Mir Mohammad Rezaee S

    2002-07-01

    Full Text Available Recently. Minalux alloy, a base metal free from Be, has been presented on the market while no special soldering has been recommended for it. On the other hand, based on the manufacturer's claim, this alloy is similar to Verabond2. The aim of this study was to investigate the tensile strength of Minalux and Verabond2, soldered by Verasolder. Twelve standard dambble shape samples, with the length of 18 mm and the diameter of 3mm, were prepared from each alloy. Six samples of each alloy were divided into two pieces with carboradom disk. Soldering gap distance was 0.3mm, measured by a special jig and they were soldered by Verasolder alloy. Six other samples, of both Iranian and foreign unsoldered alloys were considered as control group. Then samples were examined under tensile force and their tensile strength was recorded. Two- way variance analysis showed that the tensile strength of Minalux alloy and Verabond2 were not statistically significant (Verasoler 686, Minalux 723, but after soldering, such difference became significant (Minalux 308, Verabond2 432. Verabond2 showed higher tensile strength after soldering.

  12. Features of Pd-Ni-Fe solder system for vacuum brazing of low alloy steels

    International Nuclear Information System (INIS)

    Radzievskij, V.N.; Kurochko, R.S.; Lotsmanov, S.N.; Rymar', V.I.

    1975-01-01

    The brazing solder of the Pd-Ni-Fe alloyed with copper and lithium, in order to decrease the melting point and provide for a better spreading, when soldered in vacuum ensures a uniform strength of soldered joints with the base metal of low-alloyed steels of 34KHNIM-type. The properties of low-alloyed steel joints brazed with the Pd-Ni-Fe-system solder little depend on the changes in the soldering parameters. The soldered joint keeps a homogeneous structure after all the stages of heat treatment (annealing, quenching and tempering)

  13. Lead-free solder technology transfer from ASE Americas

    Energy Technology Data Exchange (ETDEWEB)

    FTHENAKIS,V.

    1999-10-19

    To safeguard the environmental friendliness of photovoltaics, the PV industry follows a proactive, long-term environmental strategy involving a life-of-cycle approach to prevent environmental damage by its processes and products from cradle to grave. Part of this strategy is to examine substituting lead-based solder on PV modules with other solder alloys. Lead is a toxic metal that, if ingested, can damage the brain, nervous system, liver and kidneys. Lead from solder in electronic products has been found to leach out from municipal waste landfills and municipal incinerator ash was found to be high in lead also because of disposed consumer electronics and batteries. Consequently, there is a movement in Europe and Japan to ban lead altogether from use in electronic products and to restrict the movement across geographical boundaries of waste containing lead. Photovoltaic modules may contain small amounts of regulated materials, which vary from one technology to another. Environmental regulations impact the cost and complexity of dealing with end-of-life PV modules. If they were classified as hazardous according to Federal or State criteria, then special requirements for material handling, disposal, record-keeping and reporting would escalate the cost of decommissioning the modules. Fthenakis showed that several of today's x-Si modules failed the US-EPA Toxicity Characteristic Leaching Procedure (TCLP) for potential leaching of Pb in landfills and also California's standard on Total Threshold Limit Concentration (TTLC) for Pb. Consequently, such modules may be classified as hazardous waste. He highlighted potential legislation in Europe and Japan which could ban or restrict the use of lead and the efforts of the printed-circuit industries in developing Pb-free solder technologies in response to such expected legislation. Japanese firms already have introduced electronic products with Pb-free solder, and one PV manufacturer in the US, ASE Americas has used a

  14. The Effect of Wetting Gravity Regime on Shear Strength of SAC and Sn-Pb Solder Lap Joints

    Science.gov (United States)

    Sona, Mrunali; Prabhu, K. Narayan

    2017-09-01

    The failure of solder joints due to imposed stresses in an electronic assembly is governed by shear bond strength. In the present study, the effect of wetting gravity regime on single-lap shear strength of Sn-0.3Ag-0.7Cu and Sn-2.5Ag-0.5Cu solder alloys reflowed between bare copper substrates as well as Ni-coated Cu substrates was investigated. Samples were reflowed for 10 s, T gz (time corresponding to the end of gravity regime) and 100 s individually and tested for single-lap shear strength. The single-lap shear test was also carried out on eutectic Sn-Pb/Cu- and Sn-Pb/Ni-coated Cu specimens to compare the shear strength values obtained with those of lead-free alloys. The eutectic Sn-Pb showed significantly higher ultimate shear strength on bare Cu substrates when compared to Sn-Ag-Cu alloys. However, SAC alloys reflowed on nickel-coated copper substrate exhibited higher shear strength when compared to eutectic Sn-Pb/Ni-coated Cu specimens. All the substrate/solder/substrate lap joint specimens that were reflowed for the time corresponding to the end of gravity regime exhibited maximum ultimate shear strength.

  15. Electron microscopy characterization of a molybdenum diffusion barrier in metallizations for chip carriers

    International Nuclear Information System (INIS)

    He Anqiang; Ivey, Douglas G.

    2004-01-01

    Mo layers have been studied as potential diffusion barriers for Au-Sn solder bonds in micro/optoelectronic device packaging. Solder was electroplated as alternating AuSn and Au 5 Sn multi-layers on wafers covered with Ti as an adhesion layer, followed by Mo as the diffusion barrier and Au as a capping layer. Samples were annealed at 340-420 deg. C for as long as 20 min. Scanning and transmission electron microscopy (SEM and TEM) were utilized to characterize interfacial reactions. Mo was found to be metallurgically stable, relative to the Au-Sn solder and the other metallization components, at temperatures up to at least 420 deg. C. However, the effectiveness of Mo as a barrier can be compromised by two factors. One of these is related to surface roughness associated with AlN or Al 2 O 3 carriers. Non-uniform metallization coverage can lead to breaks in the Mo barrier, resulting in contact between the carrier and molten solder during bonding applications. In addition, thermal stresses generated during heating and cooling can lead to cracking and spalling of the Mo and adhesion layers, exposing the carrier material to molten solder. Pre-annealing can help to relieve the thermal stresses and prevent spalling

  16. Thermal decomposition of solder flux activators under simulated wave soldering conditions

    DEFF Research Database (Denmark)

    Piotrowska, Kamila; Jellesen, Morten Stendahl; Ambat, Rajan

    2017-01-01

    /methodology/approach: Changes in the chemical structure of the activators were studied using Fourier transform infrared spectroscopy technique and were correlated to the exposure temperatures within the range of wave soldering process. The amount of residue left on the surface was estimated using standardized acid-base...... titration method as a function of temperature, time of exposure and the substrate material used. Findings: The study shows that there is a possibility of anhydride-like species formation during the thermal treatment of fluxes containing weak organic acids (WOAs) as activators (succinic and DL...

  17. Mechanical properties of Bi-In-Zn/ Cu solder joint system

    International Nuclear Information System (INIS)

    Ervina Efzan Mohd Noor; Mohammed Noori Ridha; Ahmad Badri Ismail; Nurulakmal Mohd Sharif; Kuan Yew Cheong; Tadashi Ariga; Zuhailawati Hussain

    2009-01-01

    Full text: In recent years, the pollution of environment from lead (Pb) and Pb-containing compounds in microelectronic devices attracts more and more attentions in academia and industry; the lead-free solder alloys begin to replace the lead-based solders in packaging process of some devices and components. In this works, microstructure and mechanical properties of different reflow temperature (80, 100, 120 and 140 degree Celsius) for solder joints on shear strength of Bi-In-Zn lead free solder with low melting temperature of 60 degree Celsius on Cu solder joint has been investigated. This paper will compared the mechanical properties of the Bi-In-Zn lead-free solder alloys with current lead-free solder, Sn-Ag-Cu solder alloy. The fracture surface analyses have been observed by Optical Microscope and were investigated by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray (EDX) and proved it by X-ray diffraction (XRD). (author)

  18. Correlation Between Pin Misalignment and Crack Length in THT Solder Joints

    Directory of Open Access Journals (Sweden)

    Molnar A.

    2017-06-01

    Full Text Available In this manuscript, correlations were searched for between pin misalignments relative to PCB bores and crack propagation after cyclic thermal shock tests in THT solder joints produced from lead-free solder alloys. In total, 7 compositions were examined including SAC solders with varying Ag, Cu and Ni contents. The crack propagation was initiated by cyclic thermal shock tests with 40°C / +125°C temperature profiles. Pin misalignments relative to the bores were characterized with three attributes obtained from one section of the examined solder joints. Cracks typically originated at the solder/pin or solder/bore interfaces and propagated within the solder. It was shown that pin misalignments did not have an effect on crack propagation, thus, the solder joints’ lifetime.

  19. Accelerated Metastable Solid-liquid Interdiffusion Bonding with High Thermal Stability and Power Handling

    Science.gov (United States)

    Huang, Ting-Chia; Smet, Vanessa; Kawamoto, Satomi; Pulugurtha, Markondeya R.; Tummala, Rao R.

    2018-01-01

    Emerging high-performance systems are driving the need for advanced packaging solutions such as 3-D integrated circuits (ICs) and 2.5-D system integration with increasing performance and reliability requirements for off-chip interconnections. Solid-liquid interdiffusion (SLID) bonding resulting in all-intermetallic joints has been proposed to extend the applicability of solders, but faces fundamental and manufacturing challenges hindering its wide adoption. This paper introduces a Cu-Sn SLID interconnection technology, aiming at stabilization of the microstructure in the Cu6Sn5 metastable phase rather than the usual stable Cu3Sn phase. This enables formation of a void-free interface yielding higher mechanical strength than standard SLID bonding, as well as significantly reducing the transition time. The metastable SLID technology retains the benefits of standard SLID with superior I/O pitch scalability, thermal stability and current handling capability, while advancing assembly manufacturability. In the proposed concept, the interfacial reaction is controlled by introducing Ni(P) diffusion barrier layers, designed to effectively isolate the metastable Cu6Sn5 phase preventing any further transformation. Theoretical diffusion and kinetic models were applied to design the Ni-Cu-Sn interconnection stack to achieve the targeted joint composition. A daisy chain test vehicle was used to demonstrate this technology as a first proof of concept. Full transition to Cu6Sn5 was successfully achieved within a minute at 260°C as confirmed by scanning electron microscope (SEM) and x-ray energy dispersive spectroscopy (XEDS) analysis. The joint composition was stable through 10× reflow, with outstanding bond strength averaging 90 MPa. The metastable SLID interconnections also showed excellent electromigration performance, surviving 500 h of current stressing at 105 A/cm2 at 150°C.

  20. 30 CFR 77.1112 - Welding, cutting, or soldering with arc or flame; safeguards.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Welding, cutting, or soldering with arc or... WORK AREAS OF UNDERGROUND COAL MINES Fire Protection § 77.1112 Welding, cutting, or soldering with arc or flame; safeguards. (a) When welding, cutting, or soldering with arc or flame near combustible...

  1. 30 CFR 75.1106 - Welding, cutting, or soldering with arc or flame underground.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Welding, cutting, or soldering with arc or... Protection § 75.1106 Welding, cutting, or soldering with arc or flame underground. [Statutory Provisions] All welding, cutting, or soldering with arc or flame in all underground areas of a coal mine shall, whenever...

  2. 30 CFR 77.1916 - Welding, cutting, and soldering; fire protection.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Welding, cutting, and soldering; fire... OF UNDERGROUND COAL MINES Slope and Shaft Sinking § 77.1916 Welding, cutting, and soldering; fire protection. (a) One portable fire extinguisher shall be provided where welding, cutting, or soldering with...

  3. Influence of Co and W powders on viscosity of composite solders during soldering of specially shaped diamond-abrasive tools

    Science.gov (United States)

    Sokolov, E. G.; Aref’eva, S. A.; Svistun, L. I.

    2018-03-01

    The influence of Co and W powders on the structure and the viscosity of composite solders Sn-Cu-Co-W used for the manufacture of the specially shaped diamond tools has been studied. The solders were obtained by mixing the metallic powders with an organic binder. The mixtures with and without diamonds were applied to steel rollers and shaped substrates. The sintering was carried out in a vacuum at 820 ° C with time-exposure of 40 minutes. The influence of Co and W powders on the viscosity solders was evaluated on the basis of the study of structures and according to the results of sintering specially shaped diamond tools. It was found that to provide the necessary viscosity and to obtain the uniform diamond-containing layers on the complex shaped surfaces, Sn-Cu-Co-W solder should contain 27–35 vol % of solid phase. This is achieved with a total solder content of 24–32 wt % of cobalt powder and 7 wt % of tungsten powder.

  4. An Overview of Surface Finishes and Their Role in Printed Circuit Board Solderability and Solder Joint Performance

    Energy Technology Data Exchange (ETDEWEB)

    Vianco, P.T.

    1998-10-15

    A overview has been presented on the topic of alternative surface finishes for package I/Os and circuit board features. Aspects of processability and solder joint reliability were described for the following coatings: baseline hot-dipped, plated, and plated-and-fused 100Sn and Sn-Pb coatings; Ni/Au; Pd, Ni/Pd, and Ni/Pd/Au finishes; and the recently marketed immersion Ag coatings. The Ni/Au coatings appear to provide the all-around best option in terms of solderability protection and wire bondability. Nickel/Pal ftishes offer a slightly reduced level of performance in these areas that is most likely due to variable Pd surface conditions. It is necessmy to minimize dissolved Au or Pd contents in the solder material to prevent solder joint embrittlement. Ancillary aspects that included thickness measurement techniques; the importance of finish compatibility with conformal coatings and conductive adhesives; and the need for alternative finishes for the processing of non-Pb bearing solders were discussed.

  5. Automation of experimental research of waveguide paths induction soldering

    Science.gov (United States)

    Tynchenko, V. S.; Petrenko, V. E.; Kukartsev, V. V.; Tynchenko, V. V.; Antamoshkin, O. A.

    2018-05-01

    The article presents an automated system of experimental studies of the waveguide paths induction soldering process. The system is a part of additional software for a complex of automated control of the technological process of induction soldering of thin-walled waveguide paths from aluminum alloys, expanding its capabilities. The structure of the software product, the general appearance of the controls and the potential application possibilities are presented. The utility of the developed application by approbation in a series of field experiments was considered and justified. The application of the experimental research system makes it possible to improve the process under consideration, providing the possibility of fine-tuning the control regulators, as well as keeping the statistics of the soldering process in a convenient form for analysis.

  6. Optimization of the soldering process by the DMAIC methodology

    Directory of Open Access Journals (Sweden)

    Michał Zasadzień

    2016-06-01

    Full Text Available The chapter presents the use of the DMAIC method for the analysis and improvement of the process of soldering pins in a plug connecting a bundle of wires to the board of a controller; a part of the steering system of a car. The main problem in the soldering process, that is an unsatisfactory share of bad soldered connections between the board and the plug and the instability of that number, was identified by means of a five-phase improvement process. Key points and main causes of the defect were pointed out, and process improvement measures were suggested. Due to the analysis conducted and the correct implementation of improvement measures the share of defective connections has been decreased twofold.

  7. Drinking Water Contamination Due To Lead-based Solder

    Science.gov (United States)

    Garcia, N.; Bartelt, E.; Cuff, K. E.

    2004-12-01

    The presence of lead in drinking water creates many health hazards. Exposure to lead-contaminated water can affect the brain, the central nervous system, blood cells, and kidneys, causing such problems as mental retardation, kidney disease, heart disease, stroke, and death. One way in which lead can contaminate our water supply is through the use of lead solder to join pipes. Lead solder was widely used in the past because of its ease of application as well as its low cost. Lead contamination in residential areas has previously been found to be a particularly serious problem in first-draw samples, of water that has sat stagnant in pipes overnight. To investigate the time-dependence of drinking water lead contamination, we analyzed samples taken hourly of water exposed to lead solder. While our preliminary data was insufficient to show more than a rough correlation between time of exposure and lead concentration over short periods (1-3 hours), we were able to confirm that overnight exposure of water to lead-based solder results in the presence high levels of lead. We also investigated other, external factors that previous research has indicated contribute to increased concentrations of lead. Our analysis of samples of lead-exposed water at various pH and temperatures suggests that these factors can be equally significant in terms of their contribution to elevated lead concentration levels. In particular, water that is slightly corrosive appears to severely impact the solubility of lead. As this type of water is common in much of the Northeast United States, the presence of lead-based solder in residential areas there is especially problematic. Although lead-based solder has been banned since the 1980s, it remains a serious concern, and a practical solution still requires further research.

  8. Bottom-up nanoarchitecture of semiconductor nano-building blocks by controllable in situ SEM-FIB thermal soldering method

    KAUST Repository

    Zhang, Xuan

    2017-08-10

    Here we demonstrate that the building blocks of semiconductor WO3 nanowires can be controllably soldered together by a novel nano-soldering technique of in situ SEM-FIB thermal soldering, in which the soldering temperature can precisely remain in an optimal range to avoid a strong thermal diffusion.

  9. Bottom-up nanoarchitecture of semiconductor nano-building blocks by controllable in situ SEM-FIB thermal soldering method

    KAUST Repository

    Zhang, Xuan; Zheng, Xiujun; Zhang, Hong; Zhang, Junli; Fu, Jiecai; Zhang, Qiang; Peng, Chaoyi; Bai, Feiming; Zhang, Xixiang; Peng, Yong

    2017-01-01

    Here we demonstrate that the building blocks of semiconductor WO3 nanowires can be controllably soldered together by a novel nano-soldering technique of in situ SEM-FIB thermal soldering, in which the soldering temperature can precisely remain in an optimal range to avoid a strong thermal diffusion.

  10. Welding, Bonding and Fastening, 1984

    Science.gov (United States)

    Buckley, J. D. (Editor); Stein, B. A. (Editor)

    1985-01-01

    A compilation of papers presented in a joint NASA, American Society for Metals, The George Washington University, American Welding Soceity, and Society of Manufacturing Engineers conference on Welding, Bonding, and Fastening at Langley Research Center, Hampton, VA, on October 23 to 25, 1984 is given. Papers were presented on technology developed in current research programs relevant to welding, bonding, and fastening of structural materials required in fabricating structures and mechanical systems used in the aerospace, hydrospace, and automotive industries. Topics covered in the conference included equipment, hardware and materials used when welding, brazing, and soldering, mechanical fastening, explosive welding, use of unique selected joining techniques, adhesives bonding, and nondestructive evaluation. A concept of the factory of the future was presented, followed by advanced welding techniques, automated equipment for welding, welding in a cryogenic atmosphere, blind fastening, stress corrosion resistant fasteners, fastening equipment, explosive welding of different configurations and materials, solid-state bonding, electron beam welding, new adhesives, effects of cryogenics on adhesives, and new techniques and equipment for adhesive bonding.

  11. Thermomechanical behavior of tin-rich (lead-free) solders

    Science.gov (United States)

    Sidhu, Rajen Singh

    In order to adequately characterize the behavior of ball-grid-array (BGA) Pb-free solder spheres in electronic devices, the microstructure and thermomechanical behavior need to be studied. Microstructure characterization of pure Sn, Sn-0.7Cu, Sn-3.5Ag, and Sn-3.9Ag-0.7Cu alloys was conducted using optical microscopy, scanning electron microscopy, transmission electron microscopy, image analysis, and a novel serial sectioning 3D reconstruction process. Microstructure-based finite-element method (FEM) modeling of deformation in Sn-3.5Ag alloy was conducted, and it will be shown that this technique is more accurate when compared to traditional unit cell models for simulating and understanding material behavior. The effect of cooling rate on microstructure and creep behavior of bulk Sn-rich solders was studied. The creep behavior was evaluated at 25, 95, and 120°C. Faster cooling rates were found to increase the creep strength of the solders due to refinement of the solder microstructure. The creep behavior of Sn-rich single solder spheres reflowed on Cu substrates was studied at 25, 60, 95, and 130°C. Testing was conducted using a microforce testing system, with lap-shear geometry samples. The solder joints displayed two distinct creep behaviors: (a) precipitation-strengthening (Sn-3.5Ag and Sn-3.9Ag-0.7Cu) and (b) power law creep accommodated by grain boundary sliding (GBS) (Sn and Sn-0.7Cu). The relationship between microstructural features (i.e. intermetallic particle size and spacing), stress exponents, threshold stress, and activation energies are discussed. The relationship between small-length scale creep behavior and bulk behavior is also addressed. To better understand the damage evolution in Sn-rich solder joints during thermal fatigue, the local damage will be correlated to the cyclic hysteresis behavior and crystal orientations present in the Sn phase of solder joints. FEM modeling will also be utilized to better understand the macroscopic and local

  12. Fluxless Sn-Ag bonding in vacuum using electroplated layers

    International Nuclear Information System (INIS)

    Kim, Jongsung; Lee, Chin C.

    2007-01-01

    A fluxless bonding process in vacuum environment using newly developed electroplated Sn-Ag multilayer structure at eutectic composition is presented. The new bonding process is entirely fluxless, or flux-free. It is performed in vacuum (100 mTorr), in which the oxygen content is reduced by a factor of 7600 comparing to air, to inhibit solder oxidation. In the design, Cr/Au dual layer is employed as the UBM as well as the plating seed layer. This UBM design, seldom used in the electronic industry, is explained in some details. To realize the fluxless possibility, a proper layer design of the solder structure is needed. In this connection, we wish to point out that it is hard to achieve fluxless bonding using Sn-rich alloys because these alloys have numerous Sn atoms on the surface that are easily oxidized. To prevent Sn oxidation, a thin Ag layer is plated immediately over Sn layer. XRD results confirm that this thin Ag layer does act as a barrier to prevent oxidation of the inner Sn layer. The resulting solder joints are void free as examined by a scanning acoustic microscope (SAM). SEM and EDX studies on the cross section of the joint indicate a homogeneous Sn-rich phase. The melting temperature is measured to be between 219 and 226 deg. C. This new fluxless bonding process is valuable in many applications where the use of flux is prohibited

  13. Creep deformation behavior in eutectic Sn-Ag solder joints using a novel mapping technique

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, J.P.; Guo, F.; McDougall, J.; Bieler, T.R.; Subramanian, K.N.; Park, J.K.

    1999-11-01

    Creep deformation behavior was measured for 60--100 {micro}m thick solder joints. The solder joints investigated consisted of: (1) non-composite solder joints made with eutectic Sn-Ag solder, and (2) composite solder joints with eutectic Sn-Ag solder containing 20 vol.%, 5 {micro}m diameter in-situ Cu{sub 6}Sn{sub 5} intermetallic reinforcements. All creep testing in this study was carried out at room temperature. Qualitative and quantitative assessment of creep deformation was characterized on the solder joints. Creep deformation was analyzed using a novel mapping technique where a geometrical-regular line pattern was etched over the entire solder joint using excimer laser ablation. During creep, the laser-ablation (LA) pattern becomes distorted due to deformation in the solder joint. By imaging the distortion of laser-ablation patterns using the SEM, actual deformation mapping for the entire solder joint is revealed. The technique involves sequential optical/digital imaging of the deformation versus time history during creep. By tracing and recording the deformation of the LA patterns on the solder over intervals of time, local creep data are obtained in many locations in the joint. This analysis enables global and localized creep shear strains and strain rate to be determined.

  14. Influence of solder joint length to the mechanical aspect during the thermal stress analysis

    Science.gov (United States)

    Tan, J. S.; Khor, C. Y.; Rahim, Wan Mohd Faizal Wan Abd; Ishak, Muhammad Ikman; Rosli, M. U.; Jamalludin, Mohd Riduan; Zakaria, M. S.; Nawi, M. A. M.; Aziz, M. S. Abdul; Ani, F. Che

    2017-09-01

    Solder joint is an important interconnector in surface mount technology (SMT) assembly process. The real time stress, strain and displacement of the solder joint is difficult to observe and assess the experiment. To tackle these problems, simulation analysis was employed to study the von Mises stress, strain and displacement in the thermal stress analysis by using Finite element based software. In this study, a model of leadless electronic package was considered. The thermal stress analysis was performed to investigate the effect of the solder length to those mechanical aspects. The simulation results revealed that solder length gives significant effect to the maximum von Mises stress to the solder joint. Besides, changes in solder length also influence the displacement of the solder joint in the thermal environment. The increment of the solder length significantly reduces the von Mises stress and strain on the solder joint. Thus, the understanding of the physical parameter for solder joint is important for engineer prior to designing the solder joint of the electronic component.

  15. High-Temperature Lead-Free Solder Alternatives: Possibilities and Properties

    DEFF Research Database (Denmark)

    High-temperature solders have been widely used as joining materials to provide stable interconnections that resist a severe thermal environment and also to facilitate the drive for miniaturization. High-lead containing solders have been commonly used as high-temperature solders. The development...... of high-temperature lead-free solders has become an important issue for both the electronics and automobile industries because of the health and environmental concerns associated with lead usage. Unfortunately, limited choices are available as high-temperature lead-free solders. This work outlines...... the criteria for the evaluation of a new high-temperature lead-free solder material. A list of potential ternary high-temperature lead-free solder alternatives based on the Au-Sn and Au-Ge systems is proposed. Furthermore, a comprehensive comparison of the high-temperature stability of microstructures...

  16. Reliability of lead-free solder joints with different PCB surface finishes under thermal cycling

    Energy Technology Data Exchange (ETDEWEB)

    Xia Yanghua [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)], E-mail: xia_yanghua@hotmail.com; Xie Xiaoming [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)

    2008-04-24

    The reliability of lead-free electronic assemblies under thermal cycling was investigated. Thin small outline package (TSOP) devices with FeNi leads were reflow soldered on FR4 PCB (printed circuit board) with Sn3.0Ag0.5Cu (wt%) solder. The effects of different PCB finishes (organic solderability preservative (OSP) and electroless nickel immersion gold (ENIG)) were studied. The results show that OSP finish reveals better performance than its ENIG counterparts. The crack originates at the fringe of heel fillet in both cases. The propagation of crack in the ENIG case is along the device/solder interface, while in the case of OSP, the crack extends parallel to the solder/PCB interface. When the OSP finishes are employed, many Cu6Sn5 precipitates form inside the bulk solder and have a strengthening effect on the solder joint, resulting in better reliability performance as compared to those with ENIG finishes.

  17. Soldering and brazing safety guide: A handbook on space practice for those involved in soldering and brazing

    Science.gov (United States)

    This manual provides those involved in welding and brazing with effective safety procedures for use in performance of their jobs. Hazards exist in four types of general soldering and brazing processes: (1) cleaning; (2) application of flux; (3) application of heat and filler metal; and (4) residue cleaning. Most hazards during those operations can be avoided by using care, proper ventilation, protective clothing and equipment. Specific process hazards for various methods of brazing and soldering are treated. Methods to check ventilation are presented as well as a check of personal hygiene and good maintenance practices are stressed. Several emergency first aid treatments are described.

  18. Processing and characterization of device solder interconnection and module attachment for power electronics modules

    Science.gov (United States)

    Haque, Shatil

    This research is focused on the processing of an innovative three-dimensional packaging architecture for power electronics building blocks with soldered device interconnections and subsequent characterization of the module's critical interfaces. A low-cost approach termed metal posts interconnected parallel plate structure (MPIPPS) was developed for packaging high-performance modules of power electronics building blocks (PEBB). The new concept implemented direct bonding of copper posts, not wire bonding of fine aluminum wires, to interconnect power devices as well as joining the different circuit planes together. We have demonstrated the feasibility of this packaging approach by constructing PEBB modules (consisting of Insulated Gate Bipolar Transistors (IGBTs), diodes, and a few gate driver elements and passive components). In the 1st phase of module fabrication with IGBTs with Si3N 4 passivation, we had successfully fabricated packaged devices and modules using the MPIPPS technique. These modules were tested electrically and thermally, and they operated at pulse-switch and high power stages up to 6kW. However, in the 2nd phase of module fabrication with polyimide passivated devices, we experienced significant yield problems due to metallization difficulties of these devices. The under-bump metallurgy scheme for the development of a solderable interface involved sputtering of Ti-Ni-Cu and Cr-Cu, and an electroless deposition of Zn-Ni-Au metallization. The metallization process produced excellent yield in the case of Si3N4 passivated devices. However, under the same metallization schemes, devices with a polyimide passivation exhibited inconsistent electrical contact resistance. We found that organic contaminants such as hydrocarbons remain in the form of thin monolayers on the surface, even in the case of as-received devices from the manufacturer. Moreover, in the case of polyimide passivated devices, plasma cleaning introduced a few carbon constituents on the

  19. Horizon shells and BMS-like soldering transformations

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Matthias [Albert Einstein Center for Fundamental Physics,Institute for Theoretical Physics, University of Bern,Sidlerstrasse 5, 3012 Bern (Switzerland); O’Loughlin, Martin [University of Nova Gorica,Vipavska 13, 5000 Nova Gorica (Slovenia)

    2016-03-07

    We revisit the theory of null shells in general relativity, with a particular emphasis on null shells placed at horizons of black holes. We study in detail the considerable freedom that is available in the case that one solders two metrics together across null hypersurfaces (such as Killing horizons) for which the induced metric is invariant under translations along the null generators. In this case the group of soldering transformations turns out to be infinite dimensional, and these solderings create non-trivial horizon shells containing both massless matter and impulsive gravitational wave components. We also rephrase this result in the language of Carrollian symmetry groups. To illustrate this phenomenon we discuss in detail the example of shells on the horizon of the Schwarzschild black hole (with equal interior and exterior mass), uncovering a rich classical structure at the horizon and deriving an explicit expression for the general horizon shell energy-momentum tensor. In the special case of BMS-like soldering supertranslations we find a conserved shell-energy that is strikingly similar to the standard expression for asymptotic BMS supertranslation charges, suggesting a direct relation between the physical properties of these horizon shells and the recently proposed BMS supertranslation hair of a black hole.

  20. Thermomechanical fatigue of Sn-37 wt.% Pb model solder joints

    International Nuclear Information System (INIS)

    Liu, X.W.; Plumbridge, W.J.

    2003-01-01

    The fatigue of Sn-37 wt.% Pb model solder joints has been investigated under thermomechanical and thermal cycling. Based upon an analysis of displacements during thermomechancial cycling, a model solder joint has been designed to simulate actual joints in electronic packages. The strain-stress relationship, characterised by hysteresis loops, was determined during cycling from 30 to 125 deg. C, and the stress-range monitored throughout. The number of cycles to failure, as defined by the fall in stress range, was correlated to strain range and strain energy. The strain hardening exponent, k, varied with the definition of failure and, when a stress-range drop of 50% was used, it was 0.46. Cracks were produced during pure thermal cycling without external strains applied. These arose due to the local strains caused by thermal expansion mismatches between the solder and Cu 6 Sn 5 intermetallic layer, between the phases of solder, and due to the anisotropy of the materials. The fatigue life under thermomechanical cycling was significantly inferior to that obtained in isothermal mechanical cycling. A factor contributing to this inferiority is the internal damage produced during temperature cycling

  1. Soluble Lead and Bismuth Chalcogenidometallates: Versatile Solders for Thermoelectric Materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hao [Department; Son, Jae Sung [Department; School; Dolzhnikov, Dmitriy S. [Department; Filatov, Alexander S. [Department; Hazarika, Abhijit [Department; Wang, Yuanyuan [Department; Hudson, Margaret H. [Department; Sun, Cheng-Jun [Advanced; Chattopadhyay, Soma [Physical; Talapin, Dmitri V. [Department; Center

    2017-07-27

    Here we report the syntheses of largely unexplored lead and bismuth chalcogenidometallates in the solution phase. Using N2H4 as the solvent, new compounds such as K6Pb3Te6·7N2H4 were obtained. These soluble molecular compounds underwent cation exchange processes using resin chemistry, replacing Na+ or K+ by decomposable N2H5+ or tetraethylammonium cations. They also transformed into stoichiometric lead and bismuth chalcogenide nanomaterials with the addition of metal salts. Such a versatile chemistry led to a variety of composition-matched solders to join lead and bismuth chalcogenides and tune their charge transport properties at the grain boundaries. Solution-processed thin films composed of Bi0.5Sb1.5Te3 microparticles soldered by (N2H5)6Bi0.5Sb1.5Te6 exhibited thermoelectric power factors (~28 μW/cm K2) comparable to those in vacuum-deposited Bi0.5Sb1.5Te3 films. The soldering effect can also be integrated with attractive fabrication techniques for thermoelectric modules, such as screen printing, suggesting the potential of these solders in the rational design of printable and moldable thermoelectrics.

  2. Effects of PCB thickness on adjustable fountain wave soldering

    Indian Academy of Sciences (India)

    hybrid circuit assembly, component lead tinning, and wire tinning. .... The mesh model was built and optimized with 599920 hybrid nodes as shown in figure 9. ... conducted to track the fluid motions of the two phases (i.e., molten solder and air).

  3. Soldering Characteristics and Mechanical Properties of Sn-1.0Ag-0.5Cu Solder with Minor Aluminum Addition

    Directory of Open Access Journals (Sweden)

    Yee Mei Leong

    2016-06-01

    Full Text Available Driven by the trends towards miniaturization in lead free electronic products, researchers are putting immense efforts to improve the properties and reliabilities of Sn based solders. Recently, much interest has been shown on low silver (Ag content solder SAC105 (Sn-1.0Ag-0.5Cu because of economic reasons and improvement of impact resistance as compared to SAC305 (Sn-3.0Ag-0.5Cu. The present work investigates the effect of minor aluminum (Al addition (0.1–0.5 wt.% to SAC105 on the interfacial structure between solder and copper substrate during reflow. The addition of minor Al promoted formation of small, equiaxed Cu-Al particle, which are identified as Cu3Al2. Cu3Al2 resided at the near surface/edges of the solder and exhibited higher hardness and modulus. Results show that the minor addition of Al does not alter the morphology of the interfacial intermetallic compounds, but they substantially suppress the growth of the interfacial Cu6Sn5 intermetallic compound (IMC after reflow. During isothermal aging, minor alloying Al has reduced the thickness of interfacial Cu6Sn5 IMC but has no significant effect on the thickness of Cu3Sn. It is suggested that of atoms of Al exert their influence by hindering the flow of reacting species at the interface.

  4. Soldering Characteristics and Mechanical Properties of Sn-1.0Ag-0.5Cu Solder with Minor Aluminum Addition

    Science.gov (United States)

    Leong, Yee Mei; Haseeb, A.S.M.A.

    2016-01-01

    Driven by the trends towards miniaturization in lead free electronic products, researchers are putting immense efforts to improve the properties and reliabilities of Sn based solders. Recently, much interest has been shown on low silver (Ag) content solder SAC105 (Sn-1.0Ag-0.5Cu) because of economic reasons and improvement of impact resistance as compared to SAC305 (Sn-3.0Ag-0.5Cu. The present work investigates the effect of minor aluminum (Al) addition (0.1–0.5 wt.%) to SAC105 on the interfacial structure between solder and copper substrate during reflow. The addition of minor Al promoted formation of small, equiaxed Cu-Al particle, which are identified as Cu3Al2. Cu3Al2 resided at the near surface/edges of the solder and exhibited higher hardness and modulus. Results show that the minor addition of Al does not alter the morphology of the interfacial intermetallic compounds, but they substantially suppress the growth of the interfacial Cu6Sn5 intermetallic compound (IMC) after reflow. During isothermal aging, minor alloying Al has reduced the thickness of interfacial Cu6Sn5 IMC but has no significant effect on the thickness of Cu3Sn. It is suggested that of atoms of Al exert their influence by hindering the flow of reacting species at the interface. PMID:28773645

  5. Solder wetting behavior enhancement via laser-textured surface microcosmic topography

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Haiyan [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); Shaanxi Key Laboratory of Friction Welding Technologies, Xi’an 710072 (China); Peng, Jianke [Shaanxi Key Laboratory of Friction Welding Technologies, Xi’an 710072 (China); Fu, Li, E-mail: fuli@nwpu.edu.cn [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); Shaanxi Key Laboratory of Friction Welding Technologies, Xi’an 710072 (China); Wang, Xincheng [Shaanxi Key Laboratory of Friction Welding Technologies, Xi’an 710072 (China); Xie, Yan [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)

    2016-04-15

    Graphical abstract: - Highlights: • The wetting angle of lead free solder on Cu was reduced by surface microstructure. • The wetting form of Sn-Ag-Cu solder on Cu was “non-composite surface”. • The experimental results had a sound fit with the theoretical calculation. - Abstract: In order to reduce or even replace the use of Sn-Pb solder in electronics industry, the laser-textured surface microstructures were used to enhance the wetting behavior of lead free solder during soldering. According to wetting theory and Sn-Ag-Cu lead free solder performance, we calculated and designed four microcosmic structures with the similar shape and different sizes to control the wetting behavior of lead free solder. The micro-structured surfaces with different dimensions were processed on copper plates by fiber femtosecond laser, and the effect of microstructures on wetting behavior was verified experimentally. The results showed that the wetting angle of Sn-Ag-Cu solder on the copper plate with microstructures decreased effectively compared with that on the smooth copper plate. The wetting angles had a sound fit with the theoretical values calculated by wetting model. The novel method provided a feasible route for adjusting the wetting behavior of solders and optimizing solders system.

  6. Effects of soldering methods on tensile strength of a gold-palladium metal ceramic alloy.

    Science.gov (United States)

    Ghadhanfari, Husain A; Khajah, Hasan M; Monaco, Edward A; Kim, Hyeongil

    2014-10-01

    The tensile strength obtained by conventional postceramic application soldering and laser postceramic welding may require more energy than microwave postceramic soldering, which could provide similar tensile strength values. The purpose of the study was to compare the tensile strength obtained by microwave postceramic soldering, conventional postceramic soldering, and laser postceramic welding. A gold-palladium metal ceramic alloy and gold-based solder were used in this study. Twenty-seven wax specimens were cast in gold-palladium noble metal and divided into 4 groups: laser welding with a specific postfiller noble metal, microwave soldering with a postceramic solder, conventional soldering with the same postceramic solder used in the microwave soldering group, and a nonsectioned control group. All the specimens were heat treated to simulate a normal porcelain sintering sequence. An Instron Universal Testing Machine was used to measure the tensile strength for the 4 groups. The means were analyzed statistically with 1-way ANOVA. The surface and fracture sites of the specimens were subjectively evaluated for fracture type and porosities by using a scanning electron microscope. The mean (standard deviation) ultimate tensile strength values were as follows: nonsectioned control 818 ±30 MPa, microwave 516 ±34 MPa, conventional 454 ±37 MPa, and laser weld 191 ±39 MPa. A 1-way ANOVA showed a significant difference in ultimate tensile strength among the groups (F3,23=334.5; Ptensile strength for gold and palladium noble metals than either conventional soldering or laser welding. Conventional soldering resulted in a higher tensile strength than laser welding. Under the experimental conditions described, either microwave or conventional postceramic soldering would appear to satisfy clinical requirements related to tensile strength. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  7. Effects of Metallic Nanoparticles on Interfacial Intermetallic Compounds in Tin-Based Solders for Microelectronic Packaging

    Science.gov (United States)

    Haseeb, A. S. M. A.; Arafat, M. M.; Tay, S. L.; Leong, Y. M.

    2017-10-01

    Tin (Sn)-based solders have established themselves as the main alternative to the traditional lead (Pb)-based solders in many applications. However, the reliability of the Sn-based solders continues to be a concern. In order to make Sn-based solders microstructurally more stable and hence more reliable, researchers are showing great interest in investigating the effects of the incorporation of different nanoparticles into them. This paper gives an overview of the influence of metallic nanoparticles on the characteristics of interfacial intermetallic compounds (IMCs) in Sn-based solder joints on copper substrates during reflow and thermal aging. Nanocomposite solders were prepared by mechanically blending nanoparticles of nickel (Ni), cobalt (Co), zinc (Zn), molybdenum (Mo), manganese (Mn) and titanium (Ti) with Sn-3.8Ag-0.7Cu and Sn-3.5Ag solder pastes. The composite solders were then reflowed and their wetting characteristics and interfacial microstructural evolution were investigated. Through the paste mixing route, Ni, Co, Zn and Mo nanoparticles alter the morphology and thickness of the IMCs in beneficial ways for the performance of solder joints. The thickness of Cu3Sn IMC is decreased with the addition of Ni, Co and Zn nanoparticles. The thickness of total IMC layer is decreased with the addition of Zn and Mo nanoparticles in the solder. The metallic nanoparticles can be divided into two groups. Ni, Co, and Zn nanoparticles undergo reactive dissolution during solder reflow, causing in situ alloying and therefore offering an alternative route of alloy additions to solders. Mo nanoparticles remain intact during reflow and impart their influence as discrete particles. Mechanisms of interactions between different types of metallic nanoparticles and solder are discussed.

  8. Reagent-loaded plastic microfluidic chips for detecting homocysteine

    International Nuclear Information System (INIS)

    Suk, Ji Won; Jang, Jae-Young; Cho, Jun-Hyeong

    2008-01-01

    This report describes the preliminary study on plastic microfluidic chips with pre-loaded reagents for detecting homocysteine (Hcy). All reagents needed in an Hcy immunoassay were included in a microfluidic chip to remove tedious assay steps. A simple and cost-effective bonding method was developed to realize reagent-loaded microfluidic chips. This technique uses an intermediate layer between two plastic substrates by selectively patterning polydimethylsiloxane (PDMS) on the embossed surface of microchannels and fixing the substrates under pressure. Using this bonding method, the competitive immunoassay for SAH, a converted form of Hcy, was performed without any damage to reagents in chips, and the results showed that the fluorescent signal from antibody antigen binding decreased as the SAH concentration increased. Based on the SAH immunoassay, whole immunoassay steps for Hcy detection were carried out in plastic microfluidic chips with all necessary reagents. These experiments demonstrated the feasibility of the Hcy immunoassay in microfluidic devices

  9. A wireless intraocular pressure monitoring device with a solder-filled microchannel antenna

    International Nuclear Information System (INIS)

    Varel, Çağdaş; Shih, Yi-Chun; Otis, Brian P; Böhringer, Karl F; Shen, Tueng S

    2014-01-01

    This paper presents the prototype of an intraocular pressure sensor as a major step toward building a device that can be permanently implanted during cataract surgery. The implantation will proceed through an incision of 2–3 mm using an injector, during which the complete device must be folded into a cross-section of 2 mm × 1 mm. The device uses radio frequency (RF) for wireless power and data transfer. The prototype includes an antenna, an RF chip and a pressure sensor assembled on a printed circuit board with several circuit components used for testing and calibration. The antenna is fabricated and integrated with the circuit using a fabrication method employing solder-filled microchannels embedded in an elastomer. The monitoring device is powered at 2.716 GHz from a distance of 1–2 cm. The prototype has undergone electrical and mechanical tests for antenna and sensor performance. The flexible antenna can withstand a stress of 33.4 kPa without any electrical disconnection. It did not show a significant increase in electrical resistance after 50 bending cycles with a maximum applied stress of 116 kPa. Transmitted pressure data shows an averaged sensitivity of 16.66 Hz (mm-Hg) –1 . (paper)

  10. Flip chip assembly of thinned chips for hybrid pixel detector applications

    CERN Document Server

    Fritzsch, T; Woehrmann, M; Rothermund, M; Huegging, F; Ehrmann, O; Oppermann, H; Lang, K.D

    2014-01-01

    There is a steady trend to ultra-thin microelectronic devices. Especially for future particle detector systems a reduced readout chip thickness is required to limit the loss of tracking precision due to scattering. The reduction of silicon thickness is performed at wafer level in a two-step thinning process. To minimize the risk of wafer breakage the thinned wafer needs to be handled by a carrier during the whole process chain of wafer bumping. Another key process is the flip chip assembly of thinned readout chips onto thin sensor tiles. Besides the prevention of silicon breakage the minimization of chip warpage is one additional task for a high yield and reliable flip chip process. A new technology using glass carrier wafer will be described in detail. The main advantage of this technology is the combination of a carrier support during wafer processing and the chip support during flip chip assembly. For that a glass wafer is glue-bonded onto the backside of the thinned readout chip wafer. After the bump depo...

  11. The metallurgical approach on the solder voids behaviour in surface mount devices

    International Nuclear Information System (INIS)

    Mohabattul Zaman Bukhari

    1996-01-01

    Solder voids are believed to cause poor heat dissiption in the Surface Mount devices and reduce the reliability of the devices at higher operating services. There are a lot of factors involved in creating voids such as gas/flux entrapment, wettability, outgasseous, air bubbles in the solder paste, inconsistency of solder coverage and improper metal scheme selection. This study was done to observe the behaviour of the solder voids in term of flux entrapmentt and wettability. It is believed that flux entrapment and wettability are verify this hypothesis. Two types of metal scheme were chosen which are Nickel (Ni) plated and Tin (Sn) plated heatsink. X-ray techniques such as Radiographic Inspection Analysis and EDAX were used to detect the minute solder voids. The solder voids observed on the heatsinks and Copper shims after the reflow process are believed to be a non contact voids that resulted from some portion of the surface not wetting properly

  12. Corrosive microenvironments at lead solder surfaces arising from galvanic corrosion with copper pipe.

    Science.gov (United States)

    Nguyen, Caroline K; Stone, Kendall R; Dudi, Abhijeet; Edwards, Marc A

    2010-09-15

    As stagnant water contacts copper pipe and lead solder (simulated soldered joints), a corrosion cell is formed between the metals in solder (Pb, Sn) and the copper. If the resulting galvanic current exceeds about 2 μA/cm(2), a highly corrosive microenvironment can form at the solder surface, with pH chloride concentrations at least 11 times higher than bulk water levels. Waters with relatively high chloride tend to sustain high galvanic currents, preventing passivation of the solder surface, and contributing to lead contamination of potable water supplies. The total mass of lead corroded was consistent with predictions based on the galvanic current, and lead leaching to water was correlated with galvanic current. If the concentration of sulfate in the water increased relative to chloride, galvanic currents and associated lead contamination could be greatly reduced, and solder surfaces were readily passivated.

  13. Interfacial reaction of Sn-based solder joint in the package system

    Science.gov (United States)

    Gu, Huandi

    In this thesis, I report a study on the effect of the solder size on intermetallic layer formation by comparing the morphology change and growth rate of two different size solder joint aged at a same temperature for different aging time. The layer thickness and microstructure were analyzed using scanning electron microscopy (SEM). Photoshop was used to measure the thickness of intermetallic compound. Two different size of solder joints with composition of Sn-Ag-Cu (305) were used.

  14. Laser tissue welding mediated with a protein solder

    Science.gov (United States)

    Small, Ward, IV; Heredia, Nicholas J.; Celliers, Peter M.; Da Silva, Luiz B.; Eder, David C.; Glinsky, Michael E.; London, Richard A.; Maitland, Duncan J.; Matthews, Dennis L.; Soltz, Barbara A.

    1996-05-01

    A study of laser tissue welding mediated with an indocyanine green dye-enhanced protein solder was performed. Freshly obtained sections of porcine artery were used for the experiments. Sample arterial wall thickness ranged from two to three millimeters. Incisions approximately four millimeters in length were treated using an 805 nanometer continuous- wave diode laser coupled to a one millimeter diameter fiber. Controlled parameters included the power delivered by the laser, the duration of the welding process, and the concentration of dye in the solder. A two-color infrared detection system was constructed to monitor the surface temperatures achieved at the weld site. Burst pressure measurements were made to quantify the strengths of the welds immediately following completion of the welding procedure.

  15. Quality Analysis of Welded and Soldered Joints of Cu-Nb Microcomposite Wires

    Directory of Open Access Journals (Sweden)

    Nikolaj VIŠNIAKOV

    2011-03-01

    Full Text Available Quality analysis of welded and soldered joints of Cu-Nb microcomposite wires has been performed. Quality and mechanical characteristics of joints as ultimate tensile stress limit and elongation at break were measured with an universal testing machine and controlled visually using an optical microscope. Two wires joints were soldered with silver and copper solders and put into steel and copper sleeve respectively. Another two wires joints were soldered with silver solder and welded without any reinforcement. Joints soldered with the silver solder and steel sleeve have demonstrated the best mechanical characteristics: ultimate tensile stress limit of 650 MPa and elongation at break of 0.85 %. Joints soldered with the copper sleeve have no advantages comparing with the soldered butt joint. Ultimate tensile stress limit and elongation at break were in 300 MPa - 350 MPa and in 0.35 % - 0.45 % ranges respectively. Two welded joints had ultimate tensile stress limit of 470 MPa and elongation at break of 0.71 %. In all joints the microstructure of Nb filaments was destroyed and mechanical properties have been specified by mechanical strength of copper and sleeve materials only.http://dx.doi.org/10.5755/j01.ms.17.1.242

  16. Reliability of soldered joints for automotive electronic devices; Denso buhin ni okeru handa setsugo no shinraisei

    Energy Technology Data Exchange (ETDEWEB)

    Kita, T; Mukaibo, N; Ando, K; Moriyama, M [Honda R and D Co. Ltd., Tokyo (Japan)

    1997-10-01

    Concerning the tin and lead eutectic solder, we have evaluated the reliability of three factors of intermetallic compound layer, creep and vibration which cause solder degradation. First, the stress factor was extracted from investigating the mechanism of degradation, and the best acceleration test method was fixed. Next, the acceleration test was executed to find the stress dependency and the tendency of solder degradation was modeled numerically. While the environmental stress frequency was obtained and they were put together by using a minor method, which enabled us to predict the life span of solder on the market with precision. 5 refs., 13 figs.

  17. The effect of graphene on the intermetallic and joint strength of Sn-3.5Ag lead-free solder

    Science.gov (United States)

    Mayappan, R.; Salleh, A.; Andas, J.

    2017-09-01

    Solder has been widely used in electronic industry as interconnection for electronic packaging. European Union and Japan have restricted the use of Sn-Pb solder as it contains lead which can harmful to human health and environment. Due to this, many researches have been done in order to find a suitable replacement for the lead solder. Although many lead-free solders are available, the Sn-3.5Ag solder with the addition of graphene seem to be a suitable candidate. In this study, a 0.07 wt% graphene nanosheet was added into the Sn-3.5Ag solder and this composite solder was prepared under powder metallurgy method. The solder was reacted with copper substrate at 250 °C for one minute. For joint strength analysis, two copper strips were soldered together. The solder joint was aged at temperature 100 °C for 500 hours. Scanning Electron Microscope (SEM) was used to observe the interfacial reaction and Instron machine was used to determine the joint strength. Cu6Sn5 intermetallic layer was formed at the interface between the Cu substrate and the solders. Composite solder showed the retardation of the intermetallic growth compared to the plain solder. The thickness value of the intermetallic was used to calculate the growth rate the IMC. The graphene nanosheets added solder has lower growth rate which is 3.86 × 10-15 cm2/s compared to the plain solder 7.15 × 10-15 cm2/s. Shear strength analysis show that the composite solder has higher joint compared to the plain solder.

  18. Bond Issues.

    Science.gov (United States)

    Pollack, Rachel H.

    2000-01-01

    Notes trends toward increased borrowing by colleges and universities and offers guidelines for institutions that are considering issuing bonds to raise money for capital projects. Discussion covers advantages of using bond financing, how use of bonds impacts on traditional fund raising, other cautions and concerns, and some troubling aspects of…

  19. Fully-etched apodized fiber-to-chip grating coupler on the SOI platform with -0.78 dB coupling efficiency using photonic crystals and bonded Al mirror

    DEFF Research Database (Denmark)

    Ding, Yunhong; Ou, Haiyan; Peucheret, Christophe

    2014-01-01

    We design and fabricate an ultra-high coupling efficiency fully-etched apodized grating coupler on the SOI platform using photonic crystals and bonded aluminum mirror. Ultra-high coupling efficiency of -0.78 dB with a 3 dB bandwidth of 74 nm are demonstrated.......We design and fabricate an ultra-high coupling efficiency fully-etched apodized grating coupler on the SOI platform using photonic crystals and bonded aluminum mirror. Ultra-high coupling efficiency of -0.78 dB with a 3 dB bandwidth of 74 nm are demonstrated....

  20. Pixel detector readout chip

    CERN Multimedia

    1991-01-01

    Close-up of a pixel detector readout chip. The photograph shows an aera of 1 mm x 2 mm containing 12 separate readout channels. The entire chip contains 1000 readout channels (around 80 000 transistors) covering a sensitive area of 8 mm x 5 mm. The chip has been mounted on a silicon detector to detect high energy particles.

  1. 30 CFR 77.1111 - Welding, cutting, soldering; use of fire extinguisher.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Welding, cutting, soldering; use of fire... OF UNDERGROUND COAL MINES Fire Protection § 77.1111 Welding, cutting, soldering; use of fire extinguisher. One portable fire extinguisher shall be provided at each location where welding, cutting, or...

  2. Tissue soldering with biodegradable polymer films: in-vitro investigation of hydration effects on weld strength

    Science.gov (United States)

    Sorg, Brian S.; Welch, Ashley J.

    2001-05-01

    Previous work demonstrated increased breaking strengths of tissue repaired with liquid albumin solder reinforced with a biodegradable polymer film compared to unreinforced control specimens. It was hypothesized that the breaking strength increase was due to reinforcement of the liquid solder cohesive strength. Immersion in a moist environment can decrease the adhesion of solder to tissue and negate any strength benefits gained from reinforcement. The purpose of this study was to determine if hydrated specimens repaired with reinforced solder would still be stronger than unreinforced controls. A 50%(w/v) bovine serum albumin solder with 0.5 mg/mL Indocyanine Green dye was used to repair an incision in bovine aorta. The solder was coagulated with 806-nm diode laser light. A poly(DL-lactic- co-glycolic acid) film was used to reinforce the solder (the controls had no reinforcement). The repaired tissues were immersed in phosphate buffered saline for time periods of 1 and 2 days. The breaking strengths of all of the hydrated specimens decreased compared to the acute breaking strengths. However, the reinforced specimens still had larger breaking strengths than the unreinforced controls. These results indicate that reinforcement of a liquid albumin solder may have the potential to improve the breaking strength in a clinical setting.

  3. Current Problems and Possible Solutions in High-Temperature Lead-Free Soldering

    Czech Academy of Sciences Publication Activity Database

    Kroupa, Aleš; Andersson, D.; Hoo, N.; Pearce, J.; Watson, A.; Dinsdale, A.; Mucklejohn, S.

    2012-01-01

    Roč. 21, č. 5 (2012), s. 629-637 ISSN 1059-9495 Institutional support: RVO:68081723 Keywords : lead-free soldering, * materials for high-temperature LF * new technologies for HT lead-free soldering Subject RIV: BJ - Thermodynamics Impact factor: 0.915, year: 2012

  4. Effect of Strain Rate on Joint Strength and Failure Mode of Lead-Free Solder Joints

    Science.gov (United States)

    Lin, Jian; Lei, Yongping; Fu, Hanguang; Guo, Fu

    2018-03-01

    In surface mount technology, the Sn-3.0Ag-0.5Cu solder joint has a shorter impact lifetime than a traditional lead-tin solder joint. In order to improve the impact property of SnAgCu lead-free solder joints and identify the effect of silver content on tensile strength and impact property, impact experiments were conducted at various strain rates on three selected SnAgCu based solder joints. It was found that joint failure mainly occurred in the solder material with large plastic deformation under low strain rate, while joint failure occurred at the brittle intermetallic compound layer without any plastic deformation at a high strain rate. Joint strength increased with the silver content in SnAgCu alloys in static tensile tests, while the impact property of the solder joint decreased with increasing silver content. When the strain rate was low, plastic deformation occurred with failure and the tensile strength of the Sn-3.0Ag-0.5Cu solder joint was higher than that of Sn-0.3Ag-0.7Cu; when the strain rate was high, joint failure mainly occurred at the brittle interface layer and the Sn-0.3Ag-0.7Cu solder joint had a better impact resistance with a thinner intermetallic compound layer.

  5. Development of technique for laser welding of biological tissues using laser welding device and nanocomposite solder.

    Science.gov (United States)

    Gerasimenko, A; Ichcitidze, L; Podgaetsky, V; Ryabkin, D; Pyankov, E; Saveliev, M; Selishchev, S

    2015-08-01

    The laser device for welding of biological tissues has been developed involving quality control and temperature stabilization of weld seam. Laser nanocomposite solder applied onto a wound to be weld has been used. Physicochemical properties of the nanocomposite solder have been elucidated. The nature of the tissue-organizing nanoscaffold has been analyzed at the site of biotissue welding.

  6. Failure Mechanisms of SAC/Fe-Ni Solder Joints During Thermal Cycling

    Science.gov (United States)

    Gao, Li-Yin; Liu, Zhi-Quan; Li, Cai-Fu

    2017-08-01

    Thermal cycling tests have been conducted on Sn-Ag-Cu/Fe- xNi ( x = 73 wt.% or 45 wt.%) and Sn-Ag-Cu/Cu solder joints according to the Joint Electron Device Engineering Council industrial standard to study their interfacial reliability under thermal stress. The interfacial intermetallic compounds formed for solder joints on Cu, Fe-73Ni, and Fe-45Ni were 4.5 μm, 1.7 μm, and 1.4 μm thick, respectively, after 3000 cycles, demonstrating excellent diffusion barrier effect of Fe-Ni under bump metallization (UBM). Also, two deformation modes, viz. solder extrusion and fatigue crack formation, were observed by scanning electron microscopy and three-dimensional x-ray microscopy. Solder extrusion dominated for solder joints on Cu, while fatigue cracks dominated for solder joints on Fe-45Ni and both modes were detected for those on Fe-73Ni. Solder joints on Fe-Ni presented inferior reliability during thermal cycling compared with those on Cu, with characteristic lifetime of 3441 h, 3190 h, and 1247 h for Cu, Fe-73Ni, and Fe-45Ni UBM, respectively. This degradation of the interfacial reliability for solder joints on Fe-Ni is attributed to the mismatch in coefficient of thermal expansion (CTE) at interconnection level. The CTE mismatch at microstructure level was also analyzed by electron backscatter diffraction for clearer identification of recrystallization-related deformation mechanisms.

  7. Corrosion Reliability of Lead-free Solder Systems Used in Electronics

    DEFF Research Database (Denmark)

    Li, Feng; Verdingovas, Vadimas; Medgyes, Balint

    2017-01-01

    humidity/temperature cycling tests on soldered surface insulation resistance (SIR) comb pattern. Complimentary microstructural and phase analysis of solder alloys has been carried out using the scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) methods...

  8. Reliability and microstructure of lead-free solder joints in industrial electronics after accelerated thermal aging

    NARCIS (Netherlands)

    Scaltro, F.; Biglari, M.H.; Kodentsov, A.; Yakovleva, O.; Brom, E.

    2009-01-01

    The reliability of lead-free (LF) solder joints in surface-mounted device components (SMD) has been investigated after thermo-cycle testing. Kirkendall voids have been observed at the interface component/solder together with the formation of fractures. The evolution, the morphology and the elemental

  9. Investigation of moisture uptake into printed circuit board laminate and solder mask materials

    DEFF Research Database (Denmark)

    Conseil, Helene; Gudla, Visweswara Chakravarthy; Borgaonkar, Shruti

    2017-01-01

    with different solder mask materials and exposed to saturated water vapour and liquid water. The solder masks are characterised for their microstructure and constituent phases using scanning electron microscopy and X-ray diffraction. The observations are correlated with themoisture absorption characteristic...

  10. Parental Bonding

    Directory of Open Access Journals (Sweden)

    T. Paul de Cock

    2014-08-01

    Full Text Available Estimating the early parent–child bonding relationship can be valuable in research and practice. Retrospective dimensional measures of parental bonding provide a means for assessing the experience of the early parent–child relationship. However, combinations of dimensional scores may provide information that is not readily captured with a dimensional approach. This study was designed to assess the presence of homogeneous groups in the population with similar profiles on parental bonding dimensions. Using a short version of the Parental Bonding Instrument (PBI, three parental bonding dimensions (care, authoritarianism, and overprotection were used to assess the presence of unobserved groups in the population using latent profile analysis. The class solutions were regressed on 23 covariates (demographics, parental psychopathology, loss events, and childhood contextual factors to assess the validity of the class solution. The results indicated four distinct profiles of parental bonding for fathers as well as mothers. Parental bonding profiles were significantly associated with a broad range of covariates. This person-centered approach to parental bonding has broad utility in future research which takes into account the effect of parent–child bonding, especially with regard to “affectionless control” style parenting.

  11. Eutectic-based wafer-level-packaging technique for piezoresistive MEMS accelerometers and bond characterization using molecular dynamics simulations

    Science.gov (United States)

    Aono, T.; Kazama, A.; Okada, R.; Iwasaki, T.; Isono, Y.

    2018-03-01

    We developed a eutectic-based wafer-level-packaging (WLP) technique for piezoresistive micro-electromechanical systems (MEMS) accelerometers on the basis of molecular dynamics analyses and shear tests of WLP accelerometers. The bonding conditions were experimentally and analytically determined to realize a high shear strength without solder material atoms diffusing to adhesion layers. Molecular dynamics (MD) simulations and energy dispersive x-ray (EDX) spectrometry done after the shear tests clarified the eutectic reaction of the solder materials used in this research. Energy relaxation calculations in MD showed that the diffusion of solder material atoms into the adhesive layer was promoted at a higher temperature. Tensile creep MD simulations also suggested that the local potential energy in a solder material model determined the fracture points of the model. These numerical results were supported by the shear tests and EDX analyses for WLP accelerometers. Consequently, a bonding load of 9.8 kN and temperature of 300 °C were found to be rational conditions because the shear strength was sufficient to endure the polishing process after the WLP process and there was little diffusion of solder material atoms to the adhesion layer. Also, eutectic-bonding-based WLP was effective for controlling the attenuation of the accelerometers by determining the thickness of electroplated solder materials that played the role of a cavity between the accelerometers and lids. If the gap distance between the two was less than 6.2 µm, the signal gains for x- and z-axis acceleration were less than 20 dB even at the resonance frequency due to air-damping.

  12. Properties and Microstructures of Sn-Bi-X Lead-Free Solders

    Directory of Open Access Journals (Sweden)

    Fan Yang

    2016-01-01

    Full Text Available The Sn-Bi base lead-free solders are proposed as one of the most popular alloys due to the low melting temperature (eutectic point: 139°C and low cost. However, they are not widely used because of the lower wettability, fatigue resistance, and elongation compared to traditional Sn-Pb solders. So the alloying is considered as an effective way to improve the properties of Sn-Bi solders with the addition of elements (Al, Cu, Zn, Ga, Ag, In, Sb, and rare earth and nanoparticles. In this paper, the development of Sn-Bi lead-free solders bearing elements and nanoparticles was reviewed. The variation of wettability, melting characteristic, electromigration, mechanical properties, microstructures, intermetallic compounds reaction, and creep behaviors was analyzed systematically, which can provide a reference for investigation of Sn-Bi base solders.

  13. Effect of phosphorus element on the comprehensive properties of Sn-Cu lead-free solder

    International Nuclear Information System (INIS)

    Li Guangdong; Shi Yaowu; Hao Hu; Xia Zhidong; Lei Yongping; Guo Fu

    2010-01-01

    In the present work, the effect of phosphorus on the creep fatigue properties of Sn-Cu eutectic lead-free solder was carried out. The experimental results show that the melting temperature was almost not changed with adding small amount of P element. However, the addition of trace P element led to the decrease in the property of creep fatigue. The fractography analysis by a scanning electron microscopy (SEM) shows that ductile fracture was the dominant failure behavior in the process of creep fatigue test of Sn0.7Cu and Sn0.7Cu0.005P specimens. It should be pointed out that there is significant difference in the fractographs between the joints of Sn0.7Cu solder and Sn0.7Cu0.005P solder. In the fractograph of Sn0.7Cu solder joint, the microstructure is prolonged along testing direction, and the dimples were more than the fractograph of Sn0.7Cu0.005P solder joint. In addition, the voids could be found on the Sn0.7Cu0.005P solder joint, and trace P addition may increase the rate of forming void of Sn0.7Cu solder joint. The voids can potentially lead to crack initiation or propagation sites in the solder joint. As a result, the creep fatigue of solder joint containing P such as Sn0.7Cu0.005P offers worse property compared to Sn0.7Cu solder joint.

  14. Physical properties of lead free solders in liquid and solid state

    Energy Technology Data Exchange (ETDEWEB)

    Mhiaoui, Souad

    2007-04-17

    The European legislation prohibits the use of lead containing solders in Europe. However, lead free solders have a higher melting point (typical 20%) and their mechanical characteristics are worse. Additional problems are aging and adhesion of the solder on the electronic circuits. Thus, research activities must focus on the optimization of the properties of Sn-Ag-Cu based lead free solders chosen by the industry. Two main objectives are treated in this work. In the center of the first one is the study of curious hysteresis effects of metallic cadmium-antimony alloys after thermal cycles by measuring electronic transport phenomena (thermoelectric power and electrical resistivity). The second objective, within the framework of ''cotutelle'' between the universities of Metz and of Chemnitz and supported by COST531, is to study more specifically lead free solders. A welding must well conduct electricity and well conduct and dissipate heat. In Metz, we determined the electrical conductivity, the thermoelectric power and the thermal conductivity of various lead free solders (Sn-Ag-Cu, Sn-Cu, Sn-Ag, Sn-Sb) as well in the liquid as well in the solid state. The results have been compared to classical lead-tin (Pb-Sn) solders. In Chemnitz we measured the surface tension, the interfacial tension and the density of lead free solders. We also measured the viscosity of these solders without and with additives, in particular nickel. These properties were related to the industrial problems of wettability and spreadability. Lastly, we solidified alloys under various conditions. We observed undercooling. We developed a technique of mixture of nanocrystalline powder with lead free solders ''to sow'' the liquid bath in order to obtain ''different'' solids which were examined using optical and electron microscopy. (orig.)

  15. Effect of phosphorus element on the comprehensive properties of Sn-Cu lead-free solder

    Energy Technology Data Exchange (ETDEWEB)

    Li Guangdong, E-mail: liguangdong@emails.bjut.edu.c [College of Materials Science and Engineering, Beijing University of Technology, 100 Ping Le Yuan, Chaoyang District, Beijing 100124 (China); Shi Yaowu; Hao Hu; Xia Zhidong; Lei Yongping; Guo Fu [College of Materials Science and Engineering, Beijing University of Technology, 100 Ping Le Yuan, Chaoyang District, Beijing 100124 (China)

    2010-02-18

    In the present work, the effect of phosphorus on the creep fatigue properties of Sn-Cu eutectic lead-free solder was carried out. The experimental results show that the melting temperature was almost not changed with adding small amount of P element. However, the addition of trace P element led to the decrease in the property of creep fatigue. The fractography analysis by a scanning electron microscopy (SEM) shows that ductile fracture was the dominant failure behavior in the process of creep fatigue test of Sn0.7Cu and Sn0.7Cu0.005P specimens. It should be pointed out that there is significant difference in the fractographs between the joints of Sn0.7Cu solder and Sn0.7Cu0.005P solder. In the fractograph of Sn0.7Cu solder joint, the microstructure is prolonged along testing direction, and the dimples were more than the fractograph of Sn0.7Cu0.005P solder joint. In addition, the voids could be found on the Sn0.7Cu0.005P solder joint, and trace P addition may increase the rate of forming void of Sn0.7Cu solder joint. The voids can potentially lead to crack initiation or propagation sites in the solder joint. As a result, the creep fatigue of solder joint containing P such as Sn0.7Cu0.005P offers worse property compared to Sn0.7Cu solder joint.

  16. An Approach for Impression Creep of Lead Free Microelectronic Solders

    Science.gov (United States)

    Anastasio, Onofrio A.

    2002-06-01

    Currently, the microelectronics industry is transitioning from lead-containing to lead-free solders in response to legislation in the EU and Japan. Before an alternative alloy can be designated as a replacement for current Pb-Sn extensive testing must be accomplished. One major characteristic of the alloy that must be considered is creep. Traditionally, creep testing requires numerous samples and a long tin, which thwarts the generation of comprehensive creep databases for difficult to prepare samples such as microelectronic solder joints. However, a relatively new technique, impression creep enables us to rapidly generate creep data. This test uses a cylindrical punch with a flat end to make an impression on the surface of a specimen under constant load. The steady state velocity of the indenter is found to have the same stress and temperature dependence as the conventional unidirectional creep test using bulk specimens. This thesis examines impression creep tests of eutectic Sn-Ag. A testing program and apparatus was developed constructed based on a servo hydraulic test frame. The apparatus is capable of a load resolution of 0.01N with a stability of plus/minus 0.1N, and a displacement resolution of 0.05 microns with a stability of plus/minus 0.1 microns. Samples of eutectic Sn-Ag solder were reflowed to develop the microstructure used in microelectronic packaging. Creep tests were conducted at various stresses and temperatures and showed that coarse microstructures creep more rapidly than the microstructures in the tested regime.

  17. Transected sciatic nerve repair by diode laser protein soldering.

    Science.gov (United States)

    Fekrazad, Reza; Mortezai, Omid; Pedram, MirSepehr; Kalhori, Katayoun Am; Joharchi, Khojasteh; Mansoori, Korosh; Ebrahimi, Roja; Mashhadiabbas, Fatemeh

    2017-08-01

    Despite advances in microsurgical techniques, repair of peripheral nerve injuries (PNI) is still a major challenge in regenerative medicine. The standard treatment for PNI includes suturing and anasthomosis of the transected nerve. The objective of this study was to compare neurorraphy (nerve repair) using standard suturingto diode laser protein soldering on the functional recovery of transected sciatic nerves. Thirty adult male Fischer-344 Wistar rats were randomly assigned to 3 groups: 1. The control group, no repair, 2. the standard of care suture group, and 3. The laser/protein solder group. For all three groups, the sciatic nerve was transected and the repair was done immediately. For the suture repair group, 10.0 prolene suture was used and for the laser/protein solder group a diode laser (500mW output power) in combination with bovine serum albumen and indocyanine green dye was used. Behavioral assessment by sciatic functional index was done on all rats biweekly. At 12weeks post-surgery, EMG recordings were done on all the rats and the rats were euthanized for histological evaluation of the sciatic nerves. The one-way ANOVA test was used for statistical analysis. The average time required to perform the surgery was significantly shorter for the laser-assisted nerve repair group compared to the suture group. The EMG evaluation revealed no difference between the two groups. Based on the sciatic function index the laser group was significantly better than the suture group after 12weeks (pneurorraphy using standard suturing methods. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Reliability of Wind Turbine Components-Solder Elements Fatigue Failure

    DEFF Research Database (Denmark)

    Kostandyan, Erik; Sørensen, John Dalsgaard

    2012-01-01

    on the temperature mean and temperature range. Constant terms and model errors are estimated. The proposed methods are useful to predict damage values for solder joint in power electrical components. Based on the proposed methods it is described how to find the damage level for a given temperature loading profile....... The proposed methods are discussed for application in reliability assessment of Wind Turbine’s electrical components considering physical, model and measurement uncertainties. For further research it is proposed to evaluate damage criteria for electrical components due to the operational temperature...

  19. Pressure brazing of ceramics to metals with copper solder

    International Nuclear Information System (INIS)

    Pavlova, M.A.; Metelkin, I.I.

    1986-01-01

    The effect on the quality of joints brazed with copper of different non metallized aluminooxide dielectrics with metals and alloys of a series of technological parameters (temperature, pressure, holding, and medium) in the course of pressure brazing is investigated. It is shown that in case of brazing with kovar and nickel the character of dependences is identical, however in all cases the joints with nickel are more durable. For the ceramics - molybdenum system characterized by weak interaction with copper solder kinetic dependences have no maximum and only under holding of more than 20 min the constant strength of 150-190 MPa is attained

  20. Rapid prototyping of versatile atom chips for atom interferometry applications.

    Science.gov (United States)

    Kasch, Brian; Squires, Matthew; Olson, Spencer; Kroese, Bethany; Imhof, Eric; Kohn, Rudolph; Stuhl, Benjamin; Schramm, Stacy; Stickney, James

    2016-05-01

    We present recent advances in the manipulation of ultracold atoms with ex-vacuo atom chips (i.e. atom chips that are not inside to the UHV chamber). Details will be presented of an experimental system that allows direct bonded copper (DBC) atom chips to be removed and replaced in minutes, requiring minimal re-optimization of parameters. This system has been used to create Bose-Einstein condensates, as well as magnetic waveguides with precisely tunable axial parameters, allowing double wells, pure harmonic confinement, and modified harmonic traps. We investigate the effects of higher order magnetic field contributions to the waveguide, and the implications for confined atom interferometry.

  1. Albumin solder covalently bound to a polymer membrane: New approach to improve binding strength in laser tissue soldering in-vitro.

    Science.gov (United States)

    Hiebl, B; Ascher, L; Luetzow, K; Kratz, K; Gruber, C; Mrowietz, C; Nehring, M E; Lendlein, A; Franke, R-P; Jung, F

    2018-01-01

    Laser tissue soldering (LTS) based on indocyanine green (ICG)-mediated heat-denaturation of proteins might be a promising alternative technique for micro-suturing, but up to now the problem of too weak shear strength of the solder welds in comparison to sutures is not solved. Earlier reports gave promising results showing that solder supported by carrier materials can enhance the cohesive strength of the liquid solder. In these studies, the solder was applied to the carriers by dip coating. Higher reliability of the connection between the solder and the carrier material is expected when the solder is bound covalently to the carrier material. In the present study a poly(ether imide) (PEI) membrane served as carrier material and ICG-supplemented albumin as solder substrate. The latter was covalently coupled to the carrier membrane under physiological conditions to prevent structural protein changes. As laser source a diode continuous-wave laser emitting at 808 nm with intensities between 250 mW and 1500 mW was utilized. The albumin functionalized carrier membrane was placed onto the tunica media of explanted pig thoracic aortae forming an overlapping area of approximately 0.5×0.5 cm2. All tests were performed in a dry state to prevent laser light absorption by water. Infrared spectroscopy, spectro-photometrical determination of the secondary and primary amine groups after acid orange II staining, contact angle measurements, and atomic force microscopy proved the successful functionalization of the PEI membrane with albumin. A laser power of 450 mW LTS could generate a membrane-blood vessel connection which was characterized by a shear strength of 0.08±0.002 MPa, corresponding to 15% of the tensile strength of the native blood vessel. Theoretically, an overlapping zone of 4.1 mm around the entire circumference of the blood vessel could have provided shear strength of the PEI membrane-blood vessel compound identical to the tensile strength of the native

  2. Development of Pb-Free Nanocomposite Solder Alloys

    Directory of Open Access Journals (Sweden)

    Animesh K. Basak

    2018-04-01

    Full Text Available As an alternative to conventional Pb-containing solder material, Sn–Ag–Cu (SAC based alloys are at the forefront despite limitations associated with relatively poor strength and coarsening of grains/intermetallic compounds (IMCs during aging/reflow. Accordingly, this study examines the improvement of properties of SAC alloys by incorporating nanoparticles in it. Two different types of nanoparticles were added in monolithic SAC alloy: (1 Al2O3 or (2 Fe and their effect on microstructure and thermal properties were investigated. Addition of Fe nanoparticles leads to the formation of FeSn2 IMCs alongside Ag3Sn and Cu6Sn5 from monolithic SAC alloy. Addition of Al2O3 nano-particles do not contribute to phase formation, however, remains dispersed along primary β-Sn grain boundaries and act as a grain refiner. As the addition of either Fe or Al2O3 nano-particles do not make any significant effect on thermal behavior, these reinforced nanocomposites are foreseen to provide better mechanical characteristics with respect to conventional monolithic SAC solder alloys.

  3. Impurity Effects in Electroplated-Copper Solder Joints

    Directory of Open Access Journals (Sweden)

    Hsuan Lee

    2018-05-01

    Full Text Available Copper (Cu electroplating is a mature technology, and has been extensively applied in microelectronic industry. With the development of advanced microelectronic packaging, Cu electroplating encounters new challenges for atomic deposition on a non-planar substrate and to deliver good throwing power and uniform deposit properties in a high-aspect-ratio trench. The use of organic additives plays an important role in modulating the atomic deposition to achieve successful metallic coverage and filling, which strongly relies on the adsorptive and chemical interactions among additives on the surface of growing film. However, the adsorptive characteristic of organic additives inevitably results in an incorporation of additive-derived impurities in the electroplated Cu film. The incorporation of high-level impurities originating from the use of polyethylene glycol (PEG and chlorine ions significantly affects the microstructural evolution of the electroplated Cu film, and the electroplated-Cu solder joints, leading to the formation of undesired voids at the joint interface. However, the addition of bis(3-sulfopropyl disulfide (SPS with a critical concentration suppresses the impurity incorporation and the void formation. In this article, relevant studies were reviewed, and the focus was placed on the effects of additive formula and plating parameters on the impurity incorporation in the electroplated Cu film, and the void formation in the solder joints.

  4. Alternative Solder Bond Packaging Approach for High-Voltage (HV) Pulsed Power Devices

    Science.gov (United States)

    2016-09-01

    triggered into the ON-state with a fiber - optic transmitter once the capacitor has been charged up to the desired voltage of choice with a power supply...substrate, which results in a much higher conductivity compared to highly doped p-type substrates in SiC (Fig. 1). The anode layer was etched using...reactive ion etch and then the mesa of the device was etched for total isolation. The gate contact implant was followed using nitrogen in a box

  5. Laser-tissue soldering with biodegradable polymer films in vitro: film surface morphology and hydration effects.

    Science.gov (United States)

    Sorg, B S; Welch, A J

    2001-01-01

    Previous research introduced the concept of using biodegradable polymer film reinforcement of a liquid albumin solder for improvement of the tensile strength of repaired incisions in vitro. In this study, the effect of creating small pores in the PLGA films on the weld breaking strength is studied. Additionally, the effect of hydration on the strength of the reinforced welds is investigated. A 50%(w/v) bovine serum albumin solder with 0.5 mg/mL Indocyanine Green dye was used to repair an incision in bovine aorta. The solder was coagulated with an 806-nm CW diode laser. A poly(DL-lactic-co-glycolic acid) (PLGA) film was used to reinforce the solder (the controls had solder but no reinforcement). Breaking strengths were measured acutely and after hydration in saline for 1 and 2 days. The data were analyzed by ANOVA (P < 0.05) and multiple comparisons of means were performed using the Newman-Keuls test. The creation of pores in the PLGA films qualitatively improved the film flexibility without having an apparent adverse effect on the breaking strength, while the actual technique of applying the film and solder had more of an effect. The acute maximum average breaking strengths of some of the film reinforced specimens (114.7 g-134.4 g) were significantly higher (P < 0.05) than the acute maximum average breaking strength of the unreinforced control specimens (68.3 g). Film reinforced specimens were shown to have a statistically significantly higher breaking strength than unreinforced controls after 1- and 2-day hydration. Reinforcement of liquid albumin solders in laser-assisted incision repair appears to have advantages over conventional methods that do not reinforce the cohesive strength of the solder in terms of acute breaking strength and after immersion in moist environments for short periods of time. Using a film with the solder applied to one surface only may be advantageous over other techniques.

  6. UW VLSI chip tester

    Science.gov (United States)

    McKenzie, Neil

    1989-12-01

    We present a design for a low-cost, functional VLSI chip tester. It is based on the Apple MacIntosh II personal computer. It tests chips that have up to 128 pins. All pin drivers of the tester are bidirectional; each pin is programmed independently as an input or an output. The tester can test both static and dynamic chips. Rudimentary speed testing is provided. Chips are tested by executing C programs written by the user. A software library is provided for program development. Tests run under both the Mac Operating System and A/UX. The design is implemented using Xilinx Logic Cell Arrays. Price/performance tradeoffs are discussed.

  7. The influence of silver content on structure and properties of Sn–Bi–Ag solder and Cu/solder/Cu joints

    Energy Technology Data Exchange (ETDEWEB)

    Šebo, P. [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Račianska 75, 831 02 Bratislava 3 (Slovakia); Švec, P. Sr., E-mail: Peter.Svec@savba.sk [Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11 Bratislava 45 (Slovakia); Faculty of Materials Science and Technology, Slovak University of Technology, J. Bottu 25, 917 24 Trnava (Slovakia); Janičkovič, D.; Illeková, E. [Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11 Bratislava 45 (Slovakia); Zemánková, M. [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Račianska 75, 831 02 Bratislava 3 (Slovakia); Plevachuk, Yu. [Ivan Franko National University, Department of Metal Physics, 79005 Lviv (Ukraine); Sidorov, V. [Ural State Pedagogical University, Cosmonavtov 26, 620017 Ekaterinburg (Russian Federation); Švec, P. [Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11 Bratislava 45 (Slovakia)

    2013-06-01

    The effect of silver content on structure and properties of Sn{sub 100−x}Bi{sub 10}Ag{sub x} (x=3–10 at%) lead-free solder and Cu–solder–Cu joints was investigated. The microstructure of the solder in both bulk and rapidly solidified ribbon forms was analyzed by scanning electron microscopy (SEM) and X-ray diffraction. The peculiarities in melting kinetic, studied by differential scanning calorimetry (DSC), and silver influence on it are described and discussed. The wetting of a copper substrate was examined by the sessile drop method in the temperature range of 553–673 K in air and deoxidizing gas (N{sub 2}+10%H{sub 2}) at atmospheric pressure. Cu–solder–Cu joints were also prepared in both atmospheres, and their shear strength was measured by the push-off method. The produced solders consisted of tin, bismuth and Ag{sub 3}Sn phases. The product of the interaction between the solder and the copper substrate consists of two phases: Cu{sub 3}Sn, which is adjacent to the substrate, and a Cu{sub 6}Sn{sub 5} phase. The wetting angle in air increased slightly as the silver concentration in the solder increased. Wetting of the copper substrate in N{sub 2}+10H{sub 2} gas shows the opposite tendency: the wetting angle slightly decreased as the silver content in the solder increased. The shear strength of the joints prepared in air (using flux) tends to decrease with increasing production temperature and increasing silver content in the solder. The equivalent decrease in the shear strength of the joints prepared in N{sub 2}+10H{sub 2} is more apparent.

  8. Current density redistribution from no current crowding to current crowding in Pb-free solder joints with an extremely thick Cu layer

    International Nuclear Information System (INIS)

    Han, Jung Kyu; Choi, Daechul; Fujiyoshi, Masaru; Chiwata, Nobuhiko; Tu, King-Ning

    2012-01-01

    In order to remove the effect of current crowding on electromigration, thick Cu under-bump metallization has been widely adopted in the electronics industry. Three-dimensional (3-D) integrated circuits, using through Si via Cu column interconnects, is being developed, and it seems that current crowding may not be a reliability issue. However, statistical experiments and 3-D finite element simulation indicate that there is a transition from no current crowding to current crowding, caused by void growth at the cathode. An analysis of the electromigration-induced failure mechanism in solder joints having a very thick Cu layer is presented. It is a unique failure mechanism, different from that in flip chip technology. Moreover, the study of marker displacement shows two different stages of drift velocity, which clearly demonstrates the back-stress effect and the development of compressive stress.

  9. Contamination profile on typical printed circuit board assemblies vs soldering process

    DEFF Research Database (Denmark)

    Conseil, Helene; Jellesen, Morten Stendahl; Ambat, Rajan

    2014-01-01

    Purpose – The purpose of this paper was to analyse typical printed circuit board assemblies (PCBAs) processed by reflow, wave or selective wave soldering for typical levels of process-related residues, resulting from a specific or combination of soldering processes. Typical solder flux residue...... structure was identified by Fourier transform infrared spectroscopy, while the concentration was measured using ion chromatography, and the electrical properties of the extracts were determined by measuring the leak current using a twin platinum electrode set-up. Localized extraction of residue was carried...

  10. Contamination profile of Printed Circuit Board Assemblies in relation to soldering types and conformal coating

    DEFF Research Database (Denmark)

    Conseil, Helene; Jellesen, Morten Stendahl; Ambat, Rajan

    2014-01-01

    Typical printed circuit board assemblies (PCBAs) processed by reflow, wave, or selective wave soldering were analysed for typical levels of process related residues, resulting from a specific or combination of soldering process. Typical solder flux residue distribution pattern, composition......, and concentration are profiled and reported. Presence of localized flux residues were visualized using a commercial Residue RAT gel test and chemical structure was identified by FT-IR, while the concentration was measured using ion chromatography, and the electrical properties of the extracts were determined...

  11. Modeling of high temperature- and diffusion-controlled die soldering in aluminum high pressure die casting

    DEFF Research Database (Denmark)

    Domkin, Konstantin; Hattel, Jesper Henri; Thorborg, Jesper

    2009-01-01

    of the die lifetime based on a quantitative analysis of die soldering in the framework of the numerical simulations of the die-casting process. Full 3D simulations of the process, including the filling. solidification, and the die cooling, are carried out using the casting simulation software MAGMAsoft....... The resulting transient temperature fields on the die surface and in the casting are then post-processed to estimate the die soldering. The present work deals only with the metallurgical/chemical kind of soldering which occurs at high temperatures and involves formation and growth of intermetallic layers...

  12. Eddy current quality control of soldered current-carrying busbar splices of superconducting magnets

    CERN Document Server

    Kogan, L; Savary, F; Principe, R; Datskov, V; Rozenfel'd, E; Khudjakov, B

    2015-01-01

    The eddy current technique associated with a U-shaped transducer is studied for the quality control of soldered joints between superconducting busbars ('splices'). Two other quality control techniques, based on X-rays and direct measurement of the electrical resistance, are also studied for comparison. A comparative analysis of the advantages and disadvantages of these three methods in relation to the quality control of soldered superconducting busbar cables enclosed in copper shells is used for benchmarking. The results of inspections with the U-shaped eddy current transducer carried out on several sample joints presenting different types of soldering defects show the potential of this type of nondestructive (ND) quality control technique.

  13. Quantum Devices Bonded Beneath a Superconducting Shield: Part 2

    Science.gov (United States)

    McRae, Corey Rae; Abdallah, Adel; Bejanin, Jeremy; Earnest, Carolyn; McConkey, Thomas; Pagel, Zachary; Mariantoni, Matteo

    The next-generation quantum computer will rely on physical quantum bits (qubits) organized into arrays to form error-robust logical qubits. In the superconducting quantum circuit implementation, this architecture will require the use of larger and larger chip sizes. In order for on-chip superconducting quantum computers to be scalable, various issues found in large chips must be addressed, including the suppression of box modes (due to the sample holder) and the suppression of slot modes (due to fractured ground planes). By bonding a metallized shield layer over a superconducting circuit using thin-film indium as a bonding agent, we have demonstrated proof of concept of an extensible circuit architecture that holds the key to the suppression of spurious modes. Microwave characterization of shielded transmission lines and measurement of superconducting resonators were compared to identical unshielded devices. The elimination of box modes was investigated, as well as bond characteristics including bond homogeneity and the presence of a superconducting connection.

  14. Analysis of a short beam with application to solder joints: could larger stand-off heights relieve stress?

    Science.gov (United States)

    Suhir, Ephraim

    2015-08-01

    Physically meaningful and easy-to-use analytical (mathematical) stress model is developed for a short beam with clamped and known-in-advance offset ends. The analysis is limited to elastic deformations. While the classical Timoshenko short-beam theory seeks the beam's deflection caused by the combined bending and shear deformations for the given loading, an inverse problem is considered here: the lateral force is sought for the given ends offset. In short beams this force is larger than in long beams, since, in order to achieve the given displacement (offset), the applied force has to overcome both bending and shear resistance of the beam. It is envisioned that short beams could adequately mimic the state of stress in solder joint interconnections, including ball-grid-array (BGA) systems, with large, compared to conventional joints, stand-off heights. When the package/printed-circuit-board (PCB) assembly is subjected to the change in temperature, the thermal expansion (contraction) mismatch of the package and the PCB results in an easily predictable relative displacement (offset) of the ends of the solder joint. This offset can be determined from the known external thermal mismatch strain (determined as the product of the difference in the coefficients of thermal expansion and the change in temperature) and the position of the joint with respect to the mid-cross-section of the assembly. The maximum normal and shearing stresses could be viewed as suitable criteria of the beam's (joint's) material long-term reliability. It is shown that these stresses can be brought down by employing beam-like joints, i.e., joints with an increased stand-off height compared to conventional joints. It is imperative, of course, that, if such joints are employed, there is still enough interfacial real estate, so that the BGA bonding strength is not compromised. On the other hand, owing to the lower stress level, reliability assurance might be much less of a challenge than in the case of

  15. ALICE chip processor

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    This tiny chip provides data processing for the time projection chamber on ALICE. Known as the ALICE TPC Read Out (ALTRO), this device was designed to minimize the size and power consumption of the TPC front end electronics. This single chip contains 16 low-power analogue-to-digital converters with six million transistors of digital processing and 8 kbits of data storage.

  16. Advanced flip chip packaging

    CERN Document Server

    Lai, Yi-Shao; Wong, CP

    2013-01-01

    Advanced Flip Chip Packaging presents past, present and future advances and trends in areas such as substrate technology, material development, and assembly processes. Flip chip packaging is now in widespread use in computing, communications, consumer and automotive electronics, and the demand for flip chip technology is continuing to grow in order to meet the need for products that offer better performance, are smaller, and are environmentally sustainable. This book also: Offers broad-ranging chapters with a focus on IC-package-system integration Provides viewpoints from leading industry executives and experts Details state-of-the-art achievements in process technologies and scientific research Presents a clear development history and touches on trends in the industry while also discussing up-to-date technology information Advanced Flip Chip Packaging is an ideal book for engineers, researchers, and graduate students interested in the field of flip chip packaging.

  17. Effect of Solder-Joint Geometry on the Low-Cycle Fatigue Behavior of Sn- xAg-0.7Cu

    Science.gov (United States)

    Lee, Hwa-Teng; Huang, Kuo-Chen

    2016-12-01

    Low-cycle fatigue tests of Sn-Ag-Cu (SAC) Pb-free solder joints under fixed displacement were performed to evaluate the influence of Ag content (0-3 wt.%) and solder-joint geometry (barrel and hourglass types) on solder-joint fatigue behavior and reliability. The solder joints were composed of fine particles of Ag3Sn and Cu6Sn5, which aggregated as an eutectic constituent at grain boundaries of the primary β-Sn phase and formed a dense network structure. A decrease in the Ag content resulted in coarsening of the β-Sn and eutectic phases, which, in turn, decreased the strength of the joint and caused earlier failure. Solder joints in the hourglass form exhibited better fatigue performance with longer life than barrel-type joints. The sharp contact angle formed between the solder and the Cu substrate by the barrel-type joints concentrated stress, which compromised fatigue reliability. The addition of Ag to the solder, however, enhanced fatigue performance because of strengthening caused by Ag3Sn formation. The cracks of the barrel-type SAC solder joints originated mostly at the contact corner and propagated along the interfacial layer between the interfacial intermetallic compound (IMC) and solder matrix. Hourglass-type solder joints, however, demonstrated both crack initiation and propagation in the solder matrix (solder mode). The addition of 1.5-2.0 wt.% Ag to SAC solder appears to enhance the fatigue performance of solder joints while maintaining sufficient strength.

  18. Progress on TSV technology for Medipix3RX chip

    Science.gov (United States)

    Sarajlić, M.; Pennicard, D.; Smoljanin, S.; Fritzsch, T.; Zoschke, K.; Graafsma, H.

    2017-12-01

    The progress of Through Silicon Via (TSV) technology for Medipix3RX chip done at DESY is presented here. The goal of this development is to replace the wire bonds in X-ray detectors with TSVs, in order to reduce the dead area between detectors. We obtained the first working chips assembled together with Si based sensors for X-ray detection. The 3D integration technology, including TSV, Re-distribution layer deposition, bump bonding to the Si sensor and bump bonding to the carrier PCB, was done by Fraunhofer Institute IZM in Berlin. After assembly, the module was successfully tested by recording background radiation and making X-ray images of small objects. The active area of the Medipix3RX chip is 14.1 mm×14.1 mm or 256×256 pixels. During TSV processing, the Medipix3RX chip was thinned from 775 μm original thickness, to 130 μm. The diameter of the vias is 40 μm, and the pitch between the vias is 120 μm. A liner filling approach was used to contact the TSV with the RDL on the backside of the Medipix3RX readout chip.

  19. Long-Term Effects of Soldering By-Products on Nickel-Coated Copper Wire

    Science.gov (United States)

    Rolin, T. D.; Hodge, R. E.

    2008-01-01

    An analysis of thirty-year-old, down graded flight cables was conducted to determine the makeup of a green material on the surface of the shielded wire near soldered areas and to ascertain if the green material had corroded the nickel-coated copper wire. Two likely candidates were possible due to the handling and environments to which these cables were exposed. The flux used to solder the cables is known to contain abietic acid, a carboxylic acid found in many pine rosins used for the soldering process. The resulting material copper abietate is green in color and is formed during the application of heat during soldering operations. Copper (II) chloride, which is also green in color is known to contaminate flight parts and is corrosive. Data is presented that shows the material is copper abietate, not copper (II) chloride, and more importantly that the abietate does not aggressively attack nickel-plated copper wire.

  20. Laser welding of vas deferens in rodents: initial experience with fluid solders.

    Science.gov (United States)

    Trickett, R I; Wang, D; Maitz, P; Lanzetta, M; Owen, E R

    1998-01-01

    This study evaluates the use of sutureless laser welding for vasovasostomy. In 14 rodents, the left vas deferens underwent vasovasostomy using an albumin-based solder applied to the adventitia of the vas deferens. The solder contained the dye, indocyanine green, to allow selective absorption and denaturation by a fiber-coupled 800-nm diode laser. The right vas deferens served as a control, receiving conventional layered microsurgical repair. We used a removable 4/0 nylon stent and microclamps to appose the vas deferens during repair, with no need for stay sutures. The mean time to perform laser solder repair (23.5 min) and conventional repair (23.3 min) were not significantly different (P=0.91). However, examination after 8 weeks showed that granuloma formation (G) and patency (P) rates for the conventional suture technique (G, 14%; P, 93%) were significantly better than observed for the laser solder technique (G, 57%; P, 50%).

  1. Effects of rework on adhesion of Pb-In soldered gold thick films

    International Nuclear Information System (INIS)

    Gehman, R.W.; Becka, G.A.; Losure, J.A.

    1982-02-01

    The feasibility of repeatedly reworking Pb-In soldered joints on gold thick films was evaluated. Nailhead adhesion tests on soldered thick films typically resulted in failure within the bulk solder (50 In-50 Pb). Average strengths increased with each rework, and the failure mode changed. An increase in metalization lift-off occurred with successive reworks. An investigation was initiated to determine why these changes occurred. Based on this work, the thick film adhesion to the substrate appeared to be lowered by indium reduction of cadmium oxide and by formation of a weak, brittle intermetallic compound, Au 9 In 4 . It was concluded that two solder reworks could be conducted without significant amounts of metallization lift-off during nailhead testing

  2. Microstructural Evolution and Mechanical Behavior of High Temperature Solders: Effects of High Temperature Aging

    Science.gov (United States)

    Hasnine, M.; Tolla, B.; Vahora, N.

    2018-04-01

    This paper explores the effects of aging on the mechanical behavior, microstructure evolution and IMC formation on different surface finishes of two high temperature solders, Sn-5 wt.% Ag and Sn-5 wt.% Sb. High temperature aging showed significant degradation of Sn-5 wt.% Ag solder hardness (34%) while aging has little effect on Sn-5 wt.% Sb solder. Sn-5 wt.% Ag experienced rapid grain growth as well as the coarsening of particles during aging. Sn-5 wt.% Sb showed a stable microstructure due to solid solution strengthening and the stable nature of SnSb precipitates. The increase of intermetallic compound (IMC) thickness during aging follows a parabolic relationship with time. Regression analysis (time exponent, n) indicated that IMC growth kinetics is controlled by a diffusion mechanism. The results have important implications in the selection of high temperature solders used in high temperature applications.

  3. The creep behavior of In-Ag eutectic solder joints

    International Nuclear Information System (INIS)

    Reynolds, H.L.; Kang, S.H.; Morris, J.W. Jr.; Univ. of California, Berkeley, CA

    1999-01-01

    The addition of 3 wt.% Ag to In results in a eutectic composition with improved mechanical properties while only slightly lowering the melting temperature. Steady-state creep properties of In-Ag eutectic solder joints have been measured using constant load tests at 0, 30, 60, and 90 C. Constitutive equations are derived to describe the creep behavior. The data are well represented by an equation of the form proposed by Dorn: a power-law equation applies to each independent creep mechanism. Two parallel mechanisms were observed for the In-Ag eutectic joints. The high-stress mechanism is a bulk mechanism with a thermal dependence dominated by the thermal dependence of creep in the In-rich matrix. The low-stress mechanism is a grain boundary mechanism. Results of this work are discussed with regard to creep behavior of typical eutectic systems

  4. Soldered Contact and Current Risetime Effects on Negative Polarity Wire Array Z-pinches

    International Nuclear Information System (INIS)

    Chalenski, D. A.; Kusse, B. R.; Greenly, J. B.; Blesener, I. C.; McBride, R. D.; Hammer, D. A.; Knapp, P. F.

    2009-01-01

    The Cornell University COBRA pulser is a nominal 1 MA machine, capable of driving up to 32 wire cylindrical Z-pinch arrays. COBRA can operate with variable current risetimes ranging from 100 ns to 200 ns (short and long pulse, respectively). Wires are typically strung with a ''press'' contact to the electrode hardware, where the wire is loosely pulled against the hardware and held there to establish electrical contact. The machine is normally negative, but a bolt-on convolute can be used to modify the current path and effectively produce positive polarity operation at the load.Previous research with single wires on a 1-5 kA pulser has shown that soldering the wire, thereby improving the wire/electrode contact, and operating in positive polarity can improve the energy deposition into the wire and enhance wire core expansion. Negative polarity showed no difference. Previous experiments on the negative polarity, 20 MA, 100 ns Z accelerator have shown that improving the contact improved the x-ray yield.Cornell data were collected on 16-wire Aluminum Z-pinch arrays in negative polarity. Experiments were conducted with both short and long current pulses with soldered and no-soldered wire/electrode contacts. The initiation, ablation, implosion and stagnation phases were compared for these four conditions. Time dependent x-ray signals were measured using diodes and diamond detectors. An inductive voltage monitor was used to infer minimum current radius achieved, as defined by a uniform shell of current moving radially inward, producing a time dependent inductance. Total energy data were collected with a metal-strip bolometer. Self-emission data were collected by an XUV 4-frame camera and an optical streak camera.In negative polarity and with short pulses, soldering appeared to produce a smaller radius pinch and decrease variations in the x-ray pulse shape. The bolometer, laser backlighter, 4-frame and streak cameras showed negligible differences in the initiation ablation

  5. Effects of voids on thermal-mechanical reliability of lead-free solder joints

    Directory of Open Access Journals (Sweden)

    Benabou Lahouari

    2014-06-01

    Full Text Available Reliability of electronic packages has become a major issue, particularly in systems used in electrical or hybrid cars where severe operating conditions must be met. Many studies have shown that solder interconnects are critical elements since many failure mechanisms originate from their typical response under thermal cycles. In this study, effects of voids in solder interconnects on the electronic assembly lifetime are estimated based on finite element simulations.

  6. Investigation into mechanical properties of joints of heterogeneous materials brazed with high-temperature solders

    International Nuclear Information System (INIS)

    Lomenko, V.I.; Merkushev, V.P.; Borodina, L.M.; Sycheva, T.S.; Tokhtina, O.A.; Frolov, N.N.

    1988-01-01

    Mechanical properties of copper joints with copper, 12Kh18M10T steel and KhD50 composite obtained by vacuum brazing by copper-titanium solder as compared with properties of joints brazed by PSr 72 and PMFOTsr 6-4-0.03 solders in hydrogen are studied. Dependences of joints strength on temperature of contact - reactive vacuum brazing are obtained. Possible applications of joints of dissimilar materials in electrovacuum devices subjected to the effect of dynamic loadings are established

  7. Evaluation of low-residue soldering for military and commercial applications: A report from the Low-Residue Soldering Task Force

    Energy Technology Data Exchange (ETDEWEB)

    Iman, R.L.; Anderson, D.J. [Sandia National Labs., Albuquerque, NM (United States); Burress, R.V. [SEHO (United States)] [and others

    1995-06-01

    The LRSTF combined the efforts of industry, military, and government to evaluate low-residue soldering processes for military and commercial applications. These processes were selected for evaluation because they provide a means for the military to support the presidential mandate while producing reliable hardware at a lower cost. This report presents the complete details and results of a testing program conducted by the LRSTF to evaluate low-residue soldering for printed wiring assemblies. A previous informal document provided details of the test plan used in this evaluation. Many of the details of that test plan are contained in this report. The test data are too massive to include in this report, however, these data are available on disk as Excel spreadsheets upon request. The main purpose of low-residue soldering is to eliminate waste streams during the manufacturing process.

  8. Effect of gamma radiation on micromechanical hardness of lead-free solder joint

    Energy Technology Data Exchange (ETDEWEB)

    Paulus, Wilfred [Universiti Kebangsaan Malaysia, Bangi, 43600 Kajang, Selangor (Malaysia); Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Rahman, Irman Abdul; Jalar, Azman; Kamil, Insan; Bakar, Maria Abu [Universiti Kebangsaan Malaysia, Bangi, 43600 Kajang, Selangor (Malaysia); Yusoff, Wan Yusmawati Wan [Universiti Pertahanan Nasional Malaysia, Kem Sg. Besi, 57000 Kuala Lumpur (Malaysia)

    2015-09-25

    Lead-free solders are important material in nano and microelectronic surface mounting technology for various applications in bio medicine, environmental monitoring, spacecraft and satellite instrumentation. Nevertheless solder joint in radiation environment needs higher reliability and resistance to any damage caused by ionizing radiations. In this study a lead-free 99.0Sn0.3Ag0.7Cu wt.% (SAC) solder joint was developed and subjected to various doses of gamma radiation to investigate the effects of the ionizing radiation to micromechanical hardness of the solder. Averaged hardness of the SAC joint was obtained from nanoindentation test. The results show a relationship between hardness values of indentations and the increment of radiation dose. Highest mean hardness, 0.2290 ± 0.0270 GPa was calculated on solder joint which was exposed to 5 Gray dose of gamma radiation. This value indicates possible radiation hardening effect on irradiated solder. The hardness gradually decreased to 0.1933 ± 0.0210 GPa and 0.1631 ± 0.0173 GPa when exposed to doses 50 and 500 gray respectively. These values are also lower than the hardness of non irradiated sample which was calculated as 0.2084 ± 0.0.3633 GPa indicating possible radiation damage and needs further related atomic dislocation study.

  9. Characterization of the microstructure of tin-silver lead free solder

    Energy Technology Data Exchange (ETDEWEB)

    Hurtony, Tamás, E-mail: hurtony@ett.bme.hu [Department of Electronics Technology, Budapest University of Technology and Economics, Egry József utca 18, Budapest, H-1111 (Hungary); Szakál, Alex; Almásy, László [Neutron Spectroscopy Department, Wigner Research Centre for Physics, Budapest (Hungary); Len, Adél [Neutron Spectroscopy Department, Wigner Research Centre for Physics, Budapest (Hungary); Faculty of Engineering and Information Technology, University of Pécs (Hungary); Kugler, Sándor [Department of Theoretical Physics, Budapest University of Technology and Economics (Hungary); Bonyár, Attila; Gordon, Péter [Department of Electronics Technology, Budapest University of Technology and Economics, Egry József utca 18, Budapest, H-1111 (Hungary)

    2016-07-05

    Reliability and lifetime are the two most relevant design considerations in the production of safety critical assemblies. For example in a modern automobile dozens of electronic assemblies are integrated in which thousands of solder joints are mounting the electronic components to the printed circuit boards. There exists no standardised and universal observation method for characterising the fine microstructure of such solder joints. Previously we have developed a new method for the quantitative characterization of lead-free solder alloys and in present study the validity of the proposed method is demonstrated. Microstructure of Sn-3.5Ag lead free solder alloy was investigated by electrochemical impedance spectroscopy. Solder samples were solidified with different cooling rates in order to induce differences in the microstructure. Microstructure of the ingots was revealed by selective electrochemical etching. Electrochemical impedance spectra (EIS) were measured before and after the selective etching process. The complex impedance spectra contain information about microstructure of the solder alloys. Comparison and modelling of two EIS spectra allowed obtaining a characteristic parameter of surface structure of the etched specimens. The EIS measurements were complemented with small angle neutron scattering measurements and scanning electron microscopy, in order to correlate the EIS parameter with the magnitude of the interface of the β-Sn and Ag{sub 3}Sn phases.

  10. A Probabilistic Approach to Predict Thermal Fatigue Life for Ball Grid Array Solder Joints

    Science.gov (United States)

    Wei, Helin; Wang, Kuisheng

    2011-11-01

    Numerous studies of the reliability of solder joints have been performed. Most life prediction models are limited to a deterministic approach. However, manufacturing induces uncertainty in the geometry parameters of solder joints, and the environmental temperature varies widely due to end-user diversity, creating uncertainties in the reliability of solder joints. In this study, a methodology for accounting for variation in the lifetime prediction for lead-free solder joints of ball grid array packages (PBGA) is demonstrated. The key aspects of the solder joint parameters and the cyclic temperature range related to reliability are involved. Probabilistic solutions of the inelastic strain range and thermal fatigue life based on the Engelmaier model are developed to determine the probability of solder joint failure. The results indicate that the standard deviation increases significantly when more random variations are involved. Using the probabilistic method, the influence of each variable on the thermal fatigue life is quantified. This information can be used to optimize product design and process validation acceptance criteria. The probabilistic approach creates the opportunity to identify the root causes of failed samples from product fatigue tests and field returns. The method can be applied to better understand how variation affects parameters of interest in an electronic package design with area array interconnections.

  11. The Effect of Gap Angle on Tensile Strength of Preceramic Base Metal Solder Joints.

    Science.gov (United States)

    Fattahi, Farnaz; Hashemi Ardakani, Zahra; Hashemi Ardakani, Maryam

    2015-12-01

    Soldering is a process commonly used in fabricating dental prosthesis. Since most soldered prosthesis fail at the solder joints; the joint strength is of utmost importance. The purpose of this study was to evaluate the effect of gap angle on the tensile strength of base metal solder joints. A total number of 40 Ni-Cr samples were fabricated according to ADA/ISO 9693 specifications for tensile test. Samples were cut at the midpoint of the bar, and were placed at the considered angles by employing an explicitly designed device. They were divided into 4 groups regarding the gap angle; Group C (control group) with parallel gap on steady distance of 0.2mm, Group 1: 10°, Group 2: 20°, and Group3: 30° gap angles. When soldered, the specimens were all tested for tensile strength using a universal testing machine at a cross-head speed of 0.5 mm/min with a preload of 10N. Kruskal-Wallis H test was used to compare tensile strength among the groups (ptensile strength values obtained from the study groups were respectively 307.84, 391.50, 365.18, and 368.86 MPa. The tensile strength was not statistically different among the four groups in general (p≤ 0.490). Making the gap angular at the solder joints and the subsequent unsteady increase of the gap distance would not change the tensile strength of the joint.

  12. Rheological characterisation and printing performance of Sn/Ag/Cu solder pastes

    International Nuclear Information System (INIS)

    Durairaj, R.; Ramesh, S.; Mallik, S.; Seman, A.; Ekere, N.

    2009-01-01

    Lead-free solder paste printing process accounts for majority of the assembly defects in the electronic manufacturing industry. The study investigates rheological behaviour and stencil printing performance of the lead-free solder pastes (Sn/Ag/Cu). Oscillatory stress sweep test was carried out to study the visco-elastic behaviour of the lead-free solder pastes. The visco-elastic behaviour of the paste encompasses solid and liquid characteristic of the paste, which could be used to study the flow behaviour experienced by the pastes during the stencil printing process. From this study, it was found that the solid characteristics (G') is higher than the liquid characteristic (G'') for the pastes material. In addition, the results from the study showed that the solder paste with a large G' = G'' has a higher cohesiveness resulting in poor withdrawal of the paste during the stencil printing process. The phase angles (δ) was used to correlate the quality of the dense suspensions to the formulation of solder paste materials. This study has revealed the value of having a rheological measurement for explaining and characterising solder pastes for stencil printing. As the demand for lead free pastes increases rheological measurements can assist with the formulation or development of new pastes.

  13. Study on interfacial reaction between lead-free solders and alternative surface finishes

    International Nuclear Information System (INIS)

    Siti Rabiatul Aisha; Ourdjini, A.; Saliza Osman

    2007-01-01

    This study investigates the interfacial reactions occurring during reflow soldering between Sn-Ag-Cu lead-free solder and two surface finishes: electroless nickel/ immersion gold (ENIG) and immersion silver (IAg). The study focuses on interfacial reactions evolution and growth kinetics of intermetallic compounds (IMC) formed during soldering and isothermal ageing at 150 degree Celsius for up to 2000 hours. Optical and scanning electron microscopy were used to measure IMC thickness and examine the morphology of IMC respectively, whereas the IMC phases were identified by energy dispersive X-ray analysis (EDX). The results showed that the IMC formed on ENIG finish is thinner compared to that formed on IAg finish. For IAg surface finish, Cu 6 Sn 5 IMCs with scallop morphology are formed at the solder/ surface finish interface after reflow while a second IMC, Cu 3 Sn was formed between the copper and Cu 6 Sn 5 IMC after the isothermal ageing treatment. For ENIG surface finish both (Cu,Ni) 6 Sn 5 and (Ni,Cu) 3 Sn 4 are formed after soldering. Isothermal aging of the solder joints formed on ENIG finish was found to have a significant effect on the morphology of the intermetallics by transforming to more spherical and denser morphology in addition to increase i their thickness with increased ageing time. (author)

  14. Comparative shear tests of some low temperature lead-free solder pastes

    Science.gov (United States)

    Branzei, Mihai; Plotog, Ioan; Varzaru, Gaudentiu; Cucu, Traian C.

    2016-12-01

    The range of electronic components and as a consequence, all parts of automotive electronic equipment operating temperatures in a vehicle is given by the location of that equipment, so the maximum temperature can vary between 358K and 478K1. The solder joints could be defined as passive parts of the interconnection structure of automotive electronic equipment, at a different level, from boards of electronic modules to systems. The manufacturing costs reduction necessity and the RoHS EU Directive3, 7 consequences generate the trend to create new Low-Temperature Lead-Free (LTLF) solder pastes family9. In the paper, the mechanical strength of solder joints and samples having the same transversal section as resistor 1206 case type made using the same LTLF alloys into Vapour Phase Soldering (VPS) process characterized by different cooling rates (slow and rapid) and two types of test PCBs pads finish, were benchmarked at room temperature. The presented work extends the theoretical studies and experiments upon heat transfer in VPSP in order to optimize the technology for soldering process (SP) of automotive electronic modules and could be extended for home and modern agriculture appliances industry. The shear forces (SF) values of the LTLF alloy samples having the same transversal section as resistor 1206 case type will be considered as references values of a database useful in the new solder alloy creation processes and their qualification for automotive electronics domain.

  15. Investigation on solder joint strength of nickel tin-plated and CRS tabs with PCB

    International Nuclear Information System (INIS)

    Luay Hussain

    2002-01-01

    Failure analysis on easily peels off Nickel and CRS steel tabs from PCB was carried out. Nickel Tin plated tabs, CRS steel tabs and tube were joined to the PCB using reflow/ convection soldering, in an oven. The solder paste composition is Sn36/Pb35/Ag2. Peel test was conducted and it was found that many tabs could be easily peeled off with low force. Porosities which varies from 0.4 mm to < 0.01mm in diameter, developed during soldering process and solidification was noted. It was found, the number, size and position of these porosities inside the solder layer on both parts of the tabs affect the peel strength. Scanning Electron Microscopy study and EDX analysis were carried out. It was found that the low peel strength values were due to the combination of generation and development of porosities during soldering process which act as stress concentrators and the evolution (growth) of eutectic Sn/Pb and Sn/Ni/Cu brittle grainy phase. Large eutectic microstructure with brittle Sn-Ni-Cu grainy phase enhances the failure with low peeling forces. Sample showing no feature of Sn/Ni/Cu grain gave high peeling strength value. Solder reflow, an important process, can result in strength enhancement (if it was controlled for example in a furnace). (Author)

  16. PACE3 - front-end chip for the CMS Preshower

    CERN Multimedia

    Aspel, Paul

    2003-01-01

    This is PACE3 which is the front-end chip for the CMS Preshower. In fact PACE3 is the combination of two ASICs called Delta3 and PACEAM3. Delta3 is on the left and PACEAM3 is on the right. The two ASICs are bonded together and then packaged within a single 196 pin fpBGA package.

  17. Properties and Microstructures of Sn-Ag-Cu-X Lead-Free Solder Joints in Electronic Packaging

    Directory of Open Access Journals (Sweden)

    Lei Sun

    2015-01-01

    Full Text Available SnAgCu solder alloys were considered as one of the most popular lead-free solders because of its good reliability and mechanical properties. However, there are also many problems that need to be solved for the SnAgCu solders, such as high melting point and poor wettability. In order to overcome these shortcomings, and further enhance the properties of SnAgCu solders, many researchers choose to add a series of alloying elements (In, Ti, Fe, Zn, Bi, Ni, Sb, Ga, Al, and rare earth and nanoparticles to the SnAgCu solders. In this paper, the work of SnAgCu lead-free solders containing alloying elements and nanoparticles was reviewed, and the effects of alloying elements and nanoparticles on the melting temperature, wettability, mechanical properties, hardness properties, microstructures, intermetallic compounds, and whiskers were discussed.

  18. A two-dimensional simulation model for the molded underfill process in flip chip packaging

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Xue Ru; Young, Wen Bin [National Cheng Kung University, Tainan (China)

    2015-07-15

    The flip chip process involves the deposition of solder bumps on the chip surface and their subsequent direct attachment and connection to a substrate. Underfilling traditional flip chip packaging is typically performed following a two-step approach. The first step uses capillary force to fill the gap between the chip and the substrate, and the second step uses epoxy molding compound (EMC) to overmold the package. Unlike traditional flip chip packaging, the molded underfill (MUF) concept uses a single-step approach to simultaneously achieve both underfill and overmold. MUF is a simpler and faster process. In this study, a 2D numerical model is developed to simulate the front movement of EMC flow and the void formation for different geometric parameters. The 2D model simplifies the procedures of geometric modeling and reduces the modeling time for the MUF simulation. Experiments are conducted to verify the prediction results of the model. The effect on void formation for different geometric parameters is investigated using a 2D model.

  19. Bonds Boom.

    Science.gov (United States)

    Reynolds, Cathryn

    1989-01-01

    The combined effect of the "Serrano" decision and Proposition 13 left California school districts with aging, overcrowded facilities. Chico schools won a $18.5 million general obligation bond election for facilities construction. With $11 billion needed for new school construction, California will need to tap local sources. A sidebar…

  20. An evaluation of the lap-shear test for Sn-rich solder/Cu couples: Experiments and simulation

    Science.gov (United States)

    Chawla, N.; Shen, Y.-L.; Deng, X.; Ege, E. S.

    2004-12-01

    The lap-shear technique is commonly used to evaluate the shear, creep, and thermal fatigue behavior of solder joints. We have conducted a parametric experimental and modeling study, on the effect of testing and geometrical parameters on solder/copper joint response in lap-shear. It was shown that the farfield applied strain is quite different from the actual solder strain (measured optically). Subtraction of the deformation of the Cu substrate provides a reasonable approximation of the solder strain in the elastic regime, but not in the plastic regime. Solder joint thickness has a profound effect on joint response. The solder response moves progressively closer to “true” shear response with increasing joint thickness. Numerical modeling using finite-element analyses were performed to rationalize the experimental findings. The same lap-shear configuration was used in the simulation. The input response for solder was based on the experimental tensile test result on bulk specimens. The calculated shear response, using both the commonly adopted far-field measure and the actual shear strain in solder, was found to be consistent with the trends observed in the lap-shear experiments. The geometric features were further explored to provide physical insight into the problem. Deformation of the substrate was found to greatly influence the shear behavior of the solder.

  1. Properties and Microstructures of Sn-Ag-Cu-X Lead-Free Solder Joints in Electronic Packaging

    OpenAIRE

    Sun, Lei; Zhang, Liang

    2015-01-01

    SnAgCu solder alloys were considered as one of the most popular lead-free solders because of its good reliability and mechanical properties. However, there are also many problems that need to be solved for the SnAgCu solders, such as high melting point and poor wettability. In order to overcome these shortcomings, and further enhance the properties of SnAgCu solders, many researchers choose to add a series of alloying elements (In, Ti, Fe, Zn, Bi, Ni, Sb, Ga, Al, and rare earth) and nanoparti...

  2. Effect of Multiple Reflow Cycles and Al2O3 Nanoparticles Reinforcement on Performance of SAC305 Lead-Free Solder Alloy

    Science.gov (United States)

    Tikale, Sanjay; Prabhu, K. Narayan

    2018-05-01

    The effect of Al2O3 nanoparticles reinforcement on melting behavior, microstructure evolution at the interface and joint shear strength of 96.5Sn3Ag0.5Cu (SAC305) lead-free solder alloy subjected to multiple reflow cycles was investigated. The reinforced SAC305 solder alloy compositions were prepared by adding Al2O3 nanoparticles in different weight fractions (0.05, 0.1, 0.3 and 0.5 wt.%) through mechanical dispersion. Cu/solder/Cu micro-lap-shear solder joint specimens were used to assess the shear strength of the solder joint. Differential scanning calorimetry was used to investigate the melting behavior of SAC305 solder nanocomposites. The solder joint interfacial microstructure was studied using scanning electron microscopy. The results showed that the increase in melting temperature (T L) and melting temperature range of the SAC305 solder alloy by addition of Al2O3 nanoparticles were not significant. In comparison with unreinforced SAC305 solder alloy, the reinforcement of 0.05-0.5 wt.% of Al2O3 nanoparticles improved the solder wettability. The addition of nanoparticles in minor quantity effectively suppressed the Cu6Sn5 IMC growth, improved the solder joint shear strength and ductility under multiple reflow cycles. However, the improvement in solder properties was less pronounced on increasing the nanoparticle content above 0.1 wt.% of the solder alloy.

  3. Medicaid CHIP ESPC Database

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Environmental Scanning and Program Characteristic (ESPC) Database is in a Microsoft (MS) Access format and contains Medicaid and CHIP data, for the 50 states and...

  4. Diffusion bonding

    International Nuclear Information System (INIS)

    Anderson, R.C.

    1976-01-01

    A method is described for joining beryllium to beryllium by diffusion bonding. At least one surface portion of at least two beryllium pieces is coated with nickel. A coated surface portion is positioned in a contiguous relationship with another surface portion and subjected to an environment having an atmosphere at a pressure lower than ambient pressure. A force is applied on the beryllium pieces for causing the contiguous surface portions to abut against each other. The contiguous surface portions are heated to a maximum temperature less than the melting temperature of the beryllium, and the applied force is decreased while increasing the temperature after attaining a temperature substantially above room temperature. A portion of the applied force is maintained at a temperature corresponding to about maximum temperature for a duration sufficient to effect the diffusion bond between the contiguous surface portions

  5. How Many Peripheral Solder Joints in a Surface Mounted Design Experience Inelastic Strains?

    Science.gov (United States)

    Suhir, E.; Yi, S.; Ghaffarian, R.

    2017-03-01

    It has been established that it is the peripheral solder joints that are the most vulnerable in the ball-grid-array (BGA) and column-grid-array (CGA) designs and most often fail. As far as the long-term reliability of a soldered microelectronics assembly as a whole is concerned, it makes a difference, if just one or more peripheral joints experience inelastic strains. It is clear that the low cycle fatigue lifetime of the solder system is inversely proportional to the number of joints that simultaneously experience inelastic strains. A simple and physically meaningful analytical expression (formula) is obtained for the prediction, at the design stage, of the number of such joints, if any, for the given effective thermal expansion (contraction) mismatch of the package and PCB; materials and geometrical characteristics of the package/PCB assembly; package size; and, of course, the level of the yield stress in the solder material. The suggested formula can be used to determine if the inelastic strains in the solder material could be avoided by the proper selection of the above characteristics and, if not, how many peripheral joints are expected to simultaneously experience inelastic strains. The general concept is illustrated by a numerical example carried out for a typical BGA package. The suggested analytical model (formula) is applicable to any soldered microelectronics assembly. The roles of other important factors, such as, e.g., solder material anisotropy, grain size, and their random orientation within a joint, are viewed in this analysis as less important factors than the level of the interfacial stress. The roles of these factors will be accounted for in future work and considered, in addition to the location of the joint, in a more complicated, more sophisticated, and more comprehensive reliability/fatigue model.

  6. Effect of gap distance on tensile strength of preceramic base metal solder joints.

    Science.gov (United States)

    Fattahi, Farnaz; Motamedi, Milad

    2011-01-01

    In order to fabricate prostheses with high accuracy and durability, soldering techniques have been introduced to clinical dentistry. However, these prostheses always fail at their solder joints. The purpose of this study was to evaluate the effect of gap distance on the tensile strength of base metal solder joints. Based on ADA/ISO 9693 specifications for tensile test, 40 specimens were fabricated from a Ni-Cr alloy and cut at the midpoint of 3-mm diameter bar and placed at desired positions by a specially designed device. The specimens were divided into four groups of 10 samples according to the desired solder gap distance: Group1: 0.1mm; Group2: 0.25mm; Group3: 0.5mm; and Group4: 0.75mm. After soldering, specimens were tested for tensile strength by a universal testing machine at a cross-head speed of 0.5mm/min with a preload of 10N. The mean tensile strength values of the groups were 162, 307.8, 206.1 and 336.7 MPa, respectively. The group with 0.75-mm gap had the highest and the group with 0.1-mm gap had the lowest tensile strength. Bonferroni test showed that Group1 and Group4 had statistically different values (P=0.023), but the differences between other groups were not sig-nificant at a significance level of 0.05. There was no direct relationship between increasing soldering gap distance and tensile strength of the solder joints.

  7. The critical oxide thickness for Pb-free reflow soldering on Cu substrate

    Energy Technology Data Exchange (ETDEWEB)

    Chung, C. Key [Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan (China); Assembly Test Global Materials, Intel Microelectronics Asia Ltd, B1, No. 205, Tun-Hwa North Road, 10595 Taipei, Taiwan (China); Chen, Y.J.; Li, C.C. [Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan (China); Kao, C.R., E-mail: crkao@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan (China)

    2012-06-01

    Oxidation is an undesirable effect of reflow soldering. Non-wetting occurs when the oxide layer grows above the critical thickness. Characterizing the critical oxide thickness for soldering is challenging due to oxide's nano-scale thickness and irregular topographic surface. In this paper, the critical copper oxide thickness was characterized by Time-of-Flight Secondary Ion Mass Spectrometry, Scanning Electron Microscopy, Energy-Dispersive X-ray spectroscopy, and Transmission Electron Microscopy. Copper substrates were coated with an Organic-Solderable-Preservative (OSP) layer and baked at 150 Degree-Sign C and 85% Relative Humidity for different amounts of time. The onset of the non-wetting phenomenon occurred when the oxide thickness reached 18 {+-} 5 nm. As the oxide grew beyond this critical thickness, the percentage of non-wetting solder joint increased exponentially. The growth of the oxide thickness followed a parabolic rate law. The rate constant of oxidation was 0.6 Multiplication-Sign 10{sup -15} cm{sup 2} min{sup -1}. Oxidation resulted from interdiffusion of copper and oxygen atoms through the OSP and oxide layers. The oxidation mechanism will be presented and discussed. - Highlights: Black-Right-Pointing-Pointer Critical oxide thickness for Pb free solder on Cu substrate is 18 {+-} 5 nm. Black-Right-Pointing-Pointer Above the critical oxide, non-wet solder joint increases exponentially. Black-Right-Pointing-Pointer A maximum 13-nm oxide thickness is suggested for good solder joint. Black-Right-Pointing-Pointer Initial growth of oxide thickness is logarithmic and then parabolic after 12 nm. Black-Right-Pointing-Pointer Thick oxide (360-560 nm) is formed as pores shorten the oxidation path.

  8. Improvement of the auto wire feeder machine in a de-soldering process

    Directory of Open Access Journals (Sweden)

    Niramon Nonkhukhetkhong

    2016-10-01

    Full Text Available This paper presents the methodology of the de-soldering process for rework of disk drive Head Stack Assembly (HSA units. The auto wire feeder is a machine that generates Tin (Sn on the product. This machine was determined to be one of the major sources of excess Sn on the HSA. The defect rate due to excess Sn is more than 30%, which leads to increased processing time and cost to perform additional cleaning steps. From process analysis, the major causes of excess Sn are as follows: 1 The machine cannot cut the wire all the way into the flux core area; 2 The sizes and types of soldering irons are not appropriate for the unit parts; and, 3 There are variations introduced into the de-soldering process by the workforce. This paper proposes a methodology to address all three of these causes. First, the auto wire feeder machine in the de-solder process will be adjusted in order to cut wires into flux core. Second, the types of equipment and material used in de-soldering will be optimized. Finally, a new standard method for operators, which can be controlled more easily, will be developed in order to reduce defects due to workforce related variation. After these process controls and machine adjustments were implemented, the overall Sn related problems were significantly improved. Sn contamination was reduced by 41% and cycle time was reduced by an average of 15 seconds.

  9. In vitro conjunctival incision repair by temperature-controlled laser soldering.

    Science.gov (United States)

    Norman, Galia; Rabi, Yaron; Assia, Ehud; Katzir, Abraham

    2009-01-01

    The common method of closing conjunctival incisions is by suturing, which is associated with several disadvantages. It requires skill to apply and does not always provide a watertight closure, which is required in some operations (e.g., glaucoma filtration). The purpose of the present study was to evaluate laser soldering as an alternative method for closing conjunctival incisions. Conjunctival incisions of 20 ex vivo porcine eyes were laser soldered using a temperature-controlled fiberoptic laser system and an albumin mixed with indocyanine green as a solder. The control group consisted of five repaired incisions by a 10-0 nylon running suture. The leak pressure of the repaired incisions was measured. The mean leak pressure in the laser-soldered group was 132 mm Hg compared to 4 mm Hg in the sutured group. There was no statistically significant difference in both the incision's length and distance from the limbus between the groups, before and after the procedure, indicating that there was no severe thermal damage. These preliminary results clearly demonstrate that laser soldering may be a useful method for achieving an immediate watertight conjunctival wound closure. This procedure is faster and easier to apply than suturing.

  10. Fundamentals of lead-free solder interconnect technology from microstructures to reliability

    CERN Document Server

    Lee, Tae-Kyu; Kim, Choong-Un; Ma, Hongtao

    2015-01-01

    This unique book provides an up-to-date overview of the fundamental concepts behind lead-free solder and interconnection technology. Readers will find a description of the rapidly increasing presence of electronic systems in all aspects of modern life as well as the increasing need for predictable reliability in electronic systems. The physical and mechanical properties of lead-free solders are examined in detail, and building on fundamental science, the mechanisms responsible for damage and failure evolution, which affect reliability of lead-free solder joints are identified based on microstructure evolution.  The continuing miniaturization of electronic systems will increase the demand on the performance of solder joints, which will require new alloy and processing strategies as well as interconnection design strategies. This book provides a foundation on which improved performance and new design approaches can be based.  In summary, this book:  Provides an up-to-date overview on lead-free soldering tech...

  11. Effect of temperature and flux concentration on soldering of base metal.

    Science.gov (United States)

    Lee, S Y; Lin, C T; Wang, M H; Tseng, H; Huang, H M; Dong, D R; Pan, L C; Shih, Y H

    2000-12-01

    The present study used the acoustic emission (AE) technique to evaluate interactions among soldering temperature, flux treatment, and the resultant ultimate tensile strength (UTS). Scanning electron microscopy (SEM) was used to examine fracture surfaces of the solder joints. Specimens were cast from removable partial denture alloy and then placed in a jig with a gap distance of 1.0 mm. A high-frequency soldering machine with an optical pyrometer was used for soldering at 1150 degrees C and 1200 degrees C, respectively. The flux concentrations were 67% and 75%. The soldered specimens were subjected to tensile test at a crosshead speed of 0.05 mm/min. During testing, acoustic emissions in the frequency range of 100--1200 kHz were collected, filtered, recorded, and processed by a sensing device. The results were analysed by ANOVA and Tukey LSD test. UTS at different temperatures showed no significant difference according to either mechanical or acoustic results. But in the 1200 degrees C group, the UTSs and AE counts showed significant differences (Pacoustic signals within the elastic deformation zone, while the 67% flux subgroup produced similar signals within the plastic deformation zone, either beyond the 0.2% yield point or before fracture.

  12. Nano-soldering of magnetically aligned three-dimensional nanowire networks

    International Nuclear Information System (INIS)

    Gao Fan; Gu Zhiyong

    2010-01-01

    It is extremely challenging to fabricate 3D integrated nanostructures and hybrid nanoelectronic devices. In this paper, we report a simple and efficient method to simultaneously assemble and solder nanowires into ordered 3D and electrically conductive nanowire networks. Nano-solders such as tin were fabricated onto both ends of multi-segmented nanowires by a template-assisted electrodeposition method. These nanowires were then self-assembled and soldered into large-scale 3D network structures by magnetic field assisted assembly in a liquid medium with a high boiling point. The formation of junctions/interconnects between the nanowires and the scale of the assembly were dependent on the solder reflow temperature and the strength of the magnetic field. The size of the assembled nanowire networks ranged from tens of microns to millimeters. The electrical characteristics of the 3D nanowire networks were measured by regular current-voltage (I-V) measurements using a probe station with micropositioners. Nano-solders, when combined with assembling techniques, can be used to efficiently connect and join nanowires with low contact resistance, which are very well suited for sensor integration as well as nanoelectronic device fabrication.

  13. 27 CFR 19.318 - Addition of caramel to rum or brandy and addition of oak chips to spirits.

    Science.gov (United States)

    2010-04-01

    ... or brandy and addition of oak chips to spirits. 19.318 Section 19.318 Alcohol, Tobacco Products and... PLANTS Production § 19.318 Addition of caramel to rum or brandy and addition of oak chips to spirits. Caramel possessing no material sweetening properties may be added to rum or brandy on bonded premises...

  14. Influence of Nickel Thickness and Annealing Time on the Mechanical Properties of Intermetallic Compounds Formed between Cu-Sn Solder and Substrate

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yiseul; Kwon, Jeehye; Yoo, Dayoung; Park, Sungkyu; Lee, Dajeong; Lee, Dongyun [Pusan National University, Busan (Korea, Republic of)

    2017-03-15

    Intermetallic compounds (IMCs) developed on the interface between a solder alloy and its bonding pads are an important factor in the failure of electronic circuits. In this study, the mechanical behaviors of the IMCs formed in the Cu-Ni-Sn ternary alloy system are investigated. Presumably, Ni can act as a diffusion barrier to Cu and Sn to form the IMCs. Detailed analysis of the microstructure is conducted using an electron probe micro-analyzer (EPMA). The addition of Ni softened the IMCs, which is determined based on the fracture toughness increasing (from 0.71 to 1.55 MPa√m) with the Ni layer thickness. However, above a critical amount of Ni involved in the Cu-Sn IMCs, the softening effect is diminished, and this could result from the segregation of Ni inside the IMCs. Therefore, the optimized condition must be determined in order to obtain a positive Ni effect on enhancing the reliability of the electronic circuits.

  15. Effects of Fe2NiO4 nanoparticles addition into lead free Sn–3.0Ag–0.5Cu solder pastes on microstructure and mechanical properties after reflow soldering process

    International Nuclear Information System (INIS)

    Chellvarajoo, Srivalli; Abdullah, M.Z.; Samsudin, Z.

    2015-01-01

    Highlights: • Fe 2 NiO 4 nanoparticles added into SAC 305 by mechanical mixing to form nanocomposite solder paste. • Nanoparticles in the composite solder travels with flux to the outermost surface after reflow. • The intermetallics compound reduced with the addition of nanoparticles into solder paste. • The hardness increased with the addition of limited percentage of nanoparticles into SAC 305. - Abstract: This study investigates the effects of the addition of Fe 2 NiO 4 nanoparticles into a SAC-305 lead-free solder paste. Iron, nickel, and oxide nano-elements were mixed with Pb-free solder alloying elements to produce a new form of nanocomposite solder paste, which can be a promising material in electronic packaging. The SAC-305 was mechanically added with 0.5, 1.5, and 2.5 wt.% of Fe 2 NiO 4 nanoparticles. The migration of nanoparticles in the nanocomposite solder paste to the outermost surface was clarified using the copper ‘sandwich’ method, which was performed after the reflow soldering process. Varying amounts of nanoparticles in the SAC-305 affected the IMC thickness and mechanical properties of the nanocomposite solder paste. The IMC thickness was reduced by 29.15%, 42.37%, and 59.00% after adding 0.5, 1.5, and 2.5 wt.% of Fe 2 NiO 4 nanoparticles in the SAC-305, respectively. However, via nanoindentation method, the hardness of the nanocomposite solder was improved by 44.07% and 56.82% after adding 0.5 and 1.5 wt.% of Fe 2 NiO 4 nanoparticles, respectively. If the addition of Fe 2 NiO 4 nanoparticle exceeded 1.5 wt.%, the hardness increased infinitely

  16. Eutectic and solid-state wafer bonding of silicon with gold

    International Nuclear Information System (INIS)

    Abouie, Maryam; Liu, Qi; Ivey, Douglas G.

    2012-01-01

    Highlights: ► Eutectic and solid-state Au-Si bonding are compared for both a-Si and c-Si samples. ► Exchange of a-Si and Au layer was observed in both types of bonded samples. ► Use of c-Si for bonding resulted in formation of craters at the Au/c-Si interface. ► Solid-state Au-Si bonding produces better bonds in terms of microstructure. - Abstract: The simple Au-Si eutectic, which melts at 363 °C, can be used to bond Si wafers. However, faceted craters can form at the Au/Si interface as a result of anisotropic and non-uniform reaction between Au and crystalline silicon (c-Si). These craters may adversely affect active devices on the wafers. Two possible solutions to this problem were investigated in this study. One solution was to use an amorphous silicon layer (a-Si) that was deposited on the c-Si substrate to bond with the Au. The other solution was to use solid-state bonding instead of eutectic bonding, and the wafers were bonded at a temperature (350 °C) below the Au-Si eutectic temperature. The results showed that the a-Si layer prevented the formation of craters and solid-state bonding not only required a lower bonding temperature than eutectic bonding, but also prevented spill out of the solder resulting in strong bonds with high shear strength in comparison with eutectic bonding. Using amorphous silicon, the maximum shear strength for the solid-state Au-Si bond reached 15.2 MPa, whereas for the eutectic Au-Si bond it was 13.2 MPa.

  17. A contact-lens-shaped IC chip technology

    International Nuclear Information System (INIS)

    Liu, Ching-Yu; Yang, Frank; Teng, Chih-Chiao; Fan, Long-Sheng

    2014-01-01

    We report on novel contact-lens-shaped silicon integrated circuit chip technology for applications such as forming a conforming retinal prosthesis. This is achieved by means of patterning thin films of high residual stress on top of a shaped thin silicon substrate. Several strategies are employed to achieve curvatures of various amounts. Firstly, high residual stress on a thin film makes a thin chip deform into a designed three-dimensional shape. Also, a series of patterned stress films and ‘petal-shaped’ chips were fabricated and analyzed. Large curvatures can also be formed and maintained by the packaging process of bonding the chips to constraining elements such as thin-film polymer ring structures. As a demonstration, a complementary metal oxide semiconductor transistor (CMOS) image-sensing retina chip is made into a contact-lens shape conforming to a human eyeball 12.5 mm in radius. This non-planar and flexible chip technology provides a desirable device surface interface to soft tissues or non-planar bio surfaces and opens up many other possibilities for biomedical applications. (paper)

  18. Reliability of Pb free solder alloys. Physical and mechanical properties; Pb free handa no shinraisei. Butsuri kikaiteki shinraisei

    Energy Technology Data Exchange (ETDEWEB)

    Sanji, M; Yoshino, M; Ishikawa, J; Takenaka, O [Denso Corp., Aichi (Japan)

    1997-10-01

    Properties of 19 different Pb free solders have been evaluated in comparison with Sn-37Pb eutectic solder. Pb free solders without Bi were on the same level as Sn-37Pb in tensile strength and elongation, and those with Bi had higher strength and lower elongation than Sn-37Pb. As the Bi content increased, strength was higher, and elongation was lower. In torsion fatigue tests, fatigue life of Pb free solders without Bi was longer than Sn-37Pb. The relationships of Coffin-Manson rule and Basquin rule with fatigue life was applicable to Pb free solder. Fatigue life of those is inferred from their tensile strength. 7 refs., 13 figs., 1 tab.

  19. Price of forest chips decreasing

    International Nuclear Information System (INIS)

    Hakkila, P.

    2001-01-01

    Use of forest chips was studied in 1999 in the national Puuenergia (Wood Energy) research program. Wood combusting heating plants were questioned about are the main reasons restricting the increment of the use of forest chips. Heating plants, which did not use forest chips at all or which used less than 250 m 3 (625 bulk- m 3 ) in 1999 were excluded. The main restrictions for additional use of forest chips were: too high price of forest chips; lack of suppliers and/or uncertainty of deliveries; technical problems of reception and processing of forest chips; insufficiency of boiler output especially in winter; and unsatisfactory quality of chips. The price of forest chips becomes relatively high because wood biomass used for production of forest chips has to be collected from wide area. Heavy equipment has to be used even though small fragments of wood are processed, which increases the price of chips. It is essential for forest chips that the costs can be pressed down because competition with fossil fuels, peat and industrial wood residues is hard. Low market price leads to the situation in which forest owner gets no price of the raw material, the entrepreneurs operate at the limit of profitability and renovation of machinery is difficult, and forest chips suppliers have to sell the chips at prime costs. Price of forest chips has decreased significantly during the past decade. Nominal price of forest chips is now lower than two decades ago. The real price of chips has decreased even more than the nominal price, 35% during the past decade and 20% during the last five years. Chips, made of small diameter wood, are expensive because the price includes the felling costs and harvesting is carried out at thinning lots. Price is especially high if chips are made of delimbed small diameter wood due to increased the work and reduced amount of chips. The price of logging residue chips is most profitable because cutting does not cause additional costs. Recovery of chips is

  20. Optimal selection of TLD chips

    International Nuclear Information System (INIS)

    Phung, P.; Nicoll, J.J.; Edmonds, P.; Paris, M.; Thompson, C.

    1996-01-01

    Large sets of TLD chips are often used to measure beam dose characteristics in radiotherapy. A sorting method is presented to allow optimal selection of chips from a chosen set. This method considers the variation

  1. Design of Experiments to Determine Causes of Flex Cable Solder Wicking, Discoloration and Hole Location Defects

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, Larry

    2009-04-22

    Design of Experiments (DoE) were developed and performed in an effort to discover and resolve the causes of three different manufacturing issues; large panel voids after Hot Air Solder Leveling (HASL), cable hole locations out of tolerance after lamination and delamination/solder wicking around flat flex cable circuit lands after HASL. Results from a first DoE indicated large panel voids could be eliminated by removing the pre-HASL cleaning. It also revealed eliminating the pre-HASL bake would not be detrimental when using a hard press pad lamination stackup. A second DoE indicated a reduction in hard press pad stackup lamination pressure reduced panel stretch in the y axis approximately 70%. A third DoE illustrated increasing the pre-HASL bake temperature could reduce delamination/solder wicking when using a soft press pad lamination stackup.

  2. Corrosion Behaviour of Sn-based Lead-Free Solders in Acidic Solution

    Science.gov (United States)

    Nordarina, J.; Mohd, H. Z.; Ahmad, A. M.; Muhammad, F. M. N.

    2018-03-01

    The corrosion properties of Sn-9(5Al-Zn), Sn-Cu and SAC305 were studied via potentiodynamic polarization method in an acidic solution of 1 M hydrochloric acid (HCl). Sn-9(5Al-Zn) produced different polarization profile compared with Sn-Cu and SAC305. The morphological analysis showed that small, deep grooves shaped of corrosion product formed on top of Sn-9(5Al-Zn) solder while two distinctive structures of closely packed and loosely packed corrosion product formed on top of Sn-Cu and SAC305 solder alloys. Phase analysis revealed the formations of various corrosion products such as SnO and SnO2 mainly dominant on surface of solder alloys after potentiodynamic polarization in 1 M hydrochloric acid (HCl).

  3. Au-Ge based Candidate Alloys for High-Temperature Lead-Free Solder Alternatives

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hald, John; Hattel, Jesper Henri

    2009-01-01

    Au-Ge based candidate alloys have been proposed as an alternative to high-lead content solders that are currently being used for high-temperature applications. The influence of the low melting point metals namely In, Sb and Sn to the Au-Ge eutectic with respect to the microstructure and microhard......Au-Ge based candidate alloys have been proposed as an alternative to high-lead content solders that are currently being used for high-temperature applications. The influence of the low melting point metals namely In, Sb and Sn to the Au-Ge eutectic with respect to the microstructure...... was primarily strengthened by the refined (Ge) dispersed phase. The distribution of phases played a relatively more crucial role in determining the ductility of the bulk solder alloy. In the present work it was found that among the low melting point metals, the addition of Sb to the Au-Ge eutectic would...

  4. Dissolution ad uptake of cadmium from dental gold solder alloy implants

    International Nuclear Information System (INIS)

    Bergman, B.; Bergman, M.; Soeremark, R.

    1977-01-01

    Pure metallic cadmium was irradiated by means of thermal neutrons. The irradiated cadmium ( 115 Cd) was placed in bags of gold foil and the bags were implanted subcutaneously in the neck region of mice. Two and 3 d respectively after implantation the mice were killed, the bags removed and the animals subjected to whole-body autoradiography. The autoradiograms revealed an uptake of 115 Cd in liver and kidney. In another experiment specimens of a cadmium-containing dental gold solder alloy, a cadmium-free dental casting gold alloy and soldered assemblies made of these two alloys were implanted subcutaneously in the neck region of mice. The animals were killed after 6 months; cadmium analysis showed significant increases in the cadmium concentration in liver and kidney of those mice which had been given implants of gold solder alloy. The study clearly shows that due to electrochemical corrosion cadmium can be released from implants and accumulated in the kidneys and the liver. (author)

  5. SINGLE IMAGE CAMERA CALIBRATION IN CLOSE RANGE PHOTOGRAMMETRY FOR SOLDER JOINT ANALYSIS

    Directory of Open Access Journals (Sweden)

    D. Heinemann

    2016-06-01

    Full Text Available Printed Circuit Boards (PCB play an important role in the manufacturing of electronic devices. To ensure a correct function of the PCBs a certain amount of solder paste is needed during the placement of components. The aim of the current research is to develop an real-time, closed-loop solution for the analysis of the printing process where solder is printed onto PCBs. Close range photogrammetry allows for determination of the solder volume and a subsequent correction if necessary. Photogrammetry is an image based method for three dimensional reconstruction from two dimensional image data of an object. A precise camera calibration is indispensable for an accurate reconstruction. In our certain application it is not possible to use calibration methods with two dimensional calibration targets. Therefore a special calibration target was developed and manufactured, which allows for single image camera calibration.

  6. Comparison of implant-abutment interface misfits after casting and soldering procedures.

    Science.gov (United States)

    Neves, Flávio Domingues das; Elias, Gisele Araújo; da Silva-Neto, João Paulo; de Medeiros Dantas, Lucas Costa; da Mota, Adérito Soares; Neto, Alfredo Júlio Fernandes

    2014-04-01

    The aim of this study was to compare vertical and horizontal adjustments of castable abutments after conducting casting and soldering procedures. Twelve external hexagonal implants (3.75 × 10 mm) and their UCLA abutments were divided according their manufacturer and abutment type: PUN (plastic UCLA, Neodent), PUC (plastic UCLA, Conexão), PU3i (plastic UCLA, Biomet 3i), and PUTN (plastic UCLA with Tilite milled base, Neodent). Three infrastructures of a fixed partial implant-supported bridge with 3 elements were produced for each group. The measurements of vertical (VM) and horizontal (HM) misfits were obtained via scanning electron microscopy after completion of casting and soldering. The corresponding values were determined to be biomechanically acceptable to the system, and the results were rated as a percentage. Statistical analysis establishes differences between groups by chi-square after procedures, and McNeman's test was applied to analyze the influence of soldering over casting (α ≤ .05). For the values of VM and HM, respectively, when the casting process was complete, it was observed that 83.25% and 100% (PUTN), 33.3% and 27.75% (PUN), 33.3% and 88.8% (PUC), 33.3% and 94.35% (PU3i) represented acceptable values. After completing the requisite soldering, acceptable values were 50% and 94.35% (PUTN), 16.6% and 77.7% (PUN), 38.55% and 77.7% (PUC), and 27.75% and 94.35% (PU3i). Within the limitations of this study, it can be concluded that the premachined abutments presented more acceptable VM values. The HM values were within acceptable limits before and after the soldering procedure for most groups. Further, the soldering procedure resulted in an increase of VM in all groups.

  7. In-vitro Investigations of Skin Closure using Diode Laser and Protein Solder Containing Gold Nanoshells

    Directory of Open Access Journals (Sweden)

    Mohammad Sadegh Nourbakhsh

    2010-12-01

    Full Text Available Introduction: Laser tissue soldering is a new technique for repair of various tissues including the skin, liver, articular cartilage and nerves and is a promising alternative to suture. To overcome the problems of thermal damage to surrounding tissues and low laser penetration depth, some exogenous chromophores such as gold nanoshells, a new class of nanoparticles consisting of a dielectric core surrounded by a thin metal shell, are used. The aims of this study were to use two different concentrations of gold nanoshells as the exogenous material for skin tissue soldering and also to examine the effects of laser soldering parameters on the properties of the repaired skin. Material and Methods: Two mixtures of albumin solder and different concentrations of gold nanoshells were prepared. A full thickness incision of 2×20 mm2 was made on the surface and after placing 50 μl of the solder mixture on the incision, an 810 nm diode laser was used to irradiate it at different power densities. The changes of tensile strength, σt, due to temperature rise, number of scan (Ns, and scan velocity (Vs were investigated. Results: The results showed that the tensile strength of the repaired skin increased with increasing irradiance for both gold nanoshell concentrations. In addition, at constant laser irradiance (I, the tensile strength of the repaired incision increased with increasing Ns and decreasing Vs. In our case, this corresponded to st = 1610 g/cm2 at I ~ 60 Wcm-2, T ~ 65ºC, Ns = 10 and Vs = 0.2 mms-1. Discussion and Conclusion: Gold nanoshells can be used as an indocyanine green dye (ICG alterative for laser tissue soldering.  Although by increasing the laser power density, the tensile strength of the repaired skin increases, an optimum power density must be considered due to the resulting increase in tissue temperature.

  8. Smart vision chips: An overview

    Science.gov (United States)

    Koch, Christof

    1994-01-01

    This viewgraph presentation presents four working analog VLSI vision chips: (1) time-derivative retina, (2) zero-crossing chip, (3) resistive fuse, and (4) figure-ground chip; work in progress on computing motion and neuromorphic systems; and conceptual and practical lessons learned.

  9. Mechanical performances of lead-free solder joint connections with applications in the aerospace domain

    Directory of Open Access Journals (Sweden)

    Georgiana PADURARU

    2016-03-01

    Full Text Available The paper presents some theoretical and experimental aspects regarding the tribological performances of lead-free solder joint connections, with application in the aerospace domain. In order to highlight the mechanical and tribological properties of solder joint in correlation with different pad finishes, there were made some mechanical determinations using a dedicated Share Test System. The theoretical model highlights the link between the experimental results and the influence of gravitational acceleration on the mechanical and functional integrity of the electronic assemblies that works in vibration environment. The paper novelty is provided by the interdisciplinary experiment that offers results that can be used in the mechanical, tribological, electronical and aerospace domains.

  10. A Feasibility Study of Lead Free Solders for Level 1 Packaging Applications

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hald, John; Hattel, Jesper Henri

    2009-01-01

    An attempt has been made to determine the lead free ternary combinations that satisfied the solidification requirement for a solder used in level 1 packaging applications, using the CALPHAD approach. The segregation profiles of the promising candidates were analyzed after scrutinizing the equilib......An attempt has been made to determine the lead free ternary combinations that satisfied the solidification requirement for a solder used in level 1 packaging applications, using the CALPHAD approach. The segregation profiles of the promising candidates were analyzed after scrutinizing...

  11. A review of typical thermal fatigue failure models for solder joints of electronic components

    Science.gov (United States)

    Li, Xiaoyan; Sun, Ruifeng; Wang, Yongdong

    2017-09-01

    For electronic components, cyclic plastic strain makes it easier to accumulate fatigue damage than elastic strain. When the solder joints undertake thermal expansion or cold contraction, different thermal strain of the electronic component and its corresponding substrate is caused by the different coefficient of thermal expansion of the electronic component and its corresponding substrate, leading to the phenomenon of stress concentration. So repeatedly, cracks began to sprout and gradually extend [1]. In this paper, the typical thermal fatigue failure models of solder joints of electronic components are classified and the methods of obtaining the parameters in the model are summarized based on domestic and foreign literature research.

  12. Physics of Failure as a Basis for Solder Elements Reliability Assessment in Wind Turbines

    DEFF Research Database (Denmark)

    Kostandyan, Erik; Sørensen, John Dalsgaard

    2012-01-01

    description of the reliability. A physics of failure approach is applied. A SnAg solder component used in power electronics is used as an example. Crack propagation in the SnAg solder is modeled and a model to assess the accumulated plastic strain is proposed based on a physics of failure approach. Based...... on the proposed model it is described how to find the accumulated linear damage and reliability levels for a given temperature loading profile. Using structural reliability methods the reliability levels of the electrical components are assessed by introducing scale factors for stresses....

  13. Aging treatment characteristics of solder bump joint for high reliability optical module

    International Nuclear Information System (INIS)

    Kim, Kyung-Seob; Yu, Chung-Hee; Yang, Jun-Mo

    2004-01-01

    The joint strength and fracture surfaces of Sn-37 mass% Pb and Au stud bumps for photo diode packages after isothermal aging testing were studied experimentally. Al/Au stud bumps and Cu/Sn-37 mass% Pb solders were adopted, and aged for up to 900 h to analyze the effect of intermetallic compound (IMC). The joint strength decreased with aging time. The diffraction patterns of Cu 6 Sn 5 , scallop-shaped IMCs, and planar-shaped Cu 3 Sn were characterized using transmission electron microscopy (TEM). The formation of Kirkendall voids and the growth of IMCs at the solder were found to be a possible mechanism for joint strength reduction

  14. Interfacial stresses in a bi-material assembly with a compliant bonding layer

    International Nuclear Information System (INIS)

    Suhir, E; Vujosevic, M

    2008-01-01

    We examine an elongated bi-material adhesively bonded or soldered assembly with a continuous compliant attachment (bonding layer). The assembly is subjected to external tensile forces or to bending moments applied to one of the assembly components. We develop simple predictive analytical ('mathematical') models for the evaluation of interfacial shearing (in the case of external tensile forces) and peeling (in the case of external bending moments) stresses and strains in the bonding material. The developed models can be helpful in stress-strain analyses of assemblies of the type in question and particularly for printed-circuit-board (PCB)/surface-mounted-device (SMD) assemblies employed in electronic packaging. These models enable one to particularly evaluate the maximum interfacial stresses in the bonding material from the predicted or measured strains in the PCB in the vicinity of but still outside the surface-mounted package

  15. Influence of nanoparticle addition on the formation and growth of intermetallic compounds (IMCs) in Cu/Sn–Ag–Cu/Cu solder joint during different thermal conditions

    Science.gov (United States)

    Ting Tan, Ai; Wen Tan, Ai; Yusof, Farazila

    2015-01-01

    Nanocomposite lead-free solders are gaining prominence as replacements for conventional lead-free solders such as Sn–Ag–Cu solder in the electronic packaging industry. They are fabricated by adding nanoparticles such as metallic and ceramic particles into conventional lead-free solder. It is reported that the addition of such nanoparticles could strengthen the solder matrix, refine the intermetallic compounds (IMCs) formed and suppress the growth of IMCs when the joint is subjected to different thermal conditions such as thermal aging and thermal cycling. In this paper, we first review the fundamental studies on the formation and growth of IMCs in lead-free solder joints. Subsequently, we discuss the effect of the addition of nanoparticles on IMC formation and their growth under several thermal conditions. Finally, an outlook on the future growth of research in the fabrication of nanocomposite solder is provided. PMID:27877786

  16. Influence of nanoparticle addition on the formation and growth of intermetallic compounds (IMCs) in Cu/Sn–Ag–Cu/Cu solder joint during different thermal conditions

    International Nuclear Information System (INIS)

    Ting Tan, Ai; Wen Tan, Ai; Yusof, Farazila

    2015-01-01

    Nanocomposite lead-free solders are gaining prominence as replacements for conventional lead-free solders such as Sn–Ag–Cu solder in the electronic packaging industry. They are fabricated by adding nanoparticles such as metallic and ceramic particles into conventional lead-free solder. It is reported that the addition of such nanoparticles could strengthen the solder matrix, refine the intermetallic compounds (IMCs) formed and suppress the growth of IMCs when the joint is subjected to different thermal conditions such as thermal aging and thermal cycling. In this paper, we first review the fundamental studies on the formation and growth of IMCs in lead-free solder joints. Subsequently, we discuss the effect of the addition of nanoparticles on IMC formation and their growth under several thermal conditions. Finally, an outlook on the future growth of research in the fabrication of nanocomposite solder is provided. (review)

  17. Body of Knowledge (BOK) for Copper Wire Bonds

    Science.gov (United States)

    Rutkowski, E.; Sampson, M. J.

    2015-01-01

    Copper wire bonds have replaced gold wire bonds in the majority of commercial semiconductor devices for the latest technology nodes. Although economics has been the driving mechanism to lower semiconductor packaging costs for a savings of about 20% by replacing gold wire bonds with copper, copper also has materials property advantages over gold. When compared to gold, copper has approximately: 25% lower electrical resistivity, 30% higher thermal conductivity, 75% higher tensile strength and 45% higher modulus of elasticity. Copper wire bonds on aluminum bond pads are also more mechanically robust over time and elevated temperature due to the slower intermetallic formation rate - approximately 1/100th that of the gold to aluminum intermetallic formation rate. However, there are significant tradeoffs with copper wire bonding - copper has twice the hardness of gold which results in a narrower bonding manufacturing process window and requires that the semiconductor companies design more mechanically rigid bonding pads to prevent cratering to both the bond pad and underlying chip structure. Furthermore, copper is significantly more prone to corrosion issues. The semiconductor packaging industry has responded to this corrosion concern by creating a palladium coated copper bonding wire, which is more corrosion resistant than pure copper bonding wire. Also, the selection of the device molding compound is critical because use of environmentally friendly green compounds can result in internal CTE (Coefficient of Thermal Expansion) mismatches with the copper wire bonds that can eventually lead to device failures during thermal cycling. Despite the difficult problems associated with the changeover to copper bonding wire, there are billions of copper wire bonded devices delivered annually to customers. It is noteworthy that Texas Instruments announced in October of 2014 that they are shipping microcircuits containing copper wire bonds for safety critical automotive applications

  18. Bond strength of masonry

    NARCIS (Netherlands)

    Pluijm, van der R.; Vermeltfoort, A.Th.

    1992-01-01

    Bond strength is not a well defined property of masonry. Normally three types of bond strength can be distinguished: - tensile bond strength, - shear (and torsional) bond strength, - flexural bond strength. In this contribution the behaviour and strength of masonry in deformation controlled uniaxial

  19. Two-Step Plasma Process for Cleaning Indium Bonding Bumps

    Science.gov (United States)

    Greer, Harold F.; Vasquez, Richard P.; Jones, Todd J.; Hoenk, Michael E.; Dickie, Matthew R.; Nikzad, Shouleh

    2009-01-01

    A two-step plasma process has been developed as a means of removing surface oxide layers from indium bumps used in flip-chip hybridization (bump bonding) of integrated circuits. The two-step plasma process makes it possible to remove surface indium oxide, without incurring the adverse effects of the acid etching process.

  20. Investigation of ball bond integrity for 0.8 mil (20 microns) diameter gold bonding wire on low k die in wire bonding technology

    Science.gov (United States)

    Kudtarkar, Santosh Anil

    Microelectronics technology has been undergoing continuous scaling to accommodate customer driven demand for smaller, faster and cheaper products. This demand has been satisfied by using novel materials, design techniques and processes. This results in challenges for the chip connection technology and also the package technology. The focus of this research endeavor was restricted to wire bond interconnect technology using gold bonding wires. Wire bond technology is often regarded as a simple first level interconnection technique. In reality, however, this is a complex process that requires a thorough understanding of the interactions between the design, material and process variables, and their impact on the reliability of the bond formed during this process. This research endeavor primarily focused on low diameter, 0.8 mil thick (20 mum) diameter gold bonding wire. Within the scope of this research, the integrity of the ball bond formed by 1.0 mil (25 mum) and 0.8 mil (20 mum) diameter wires was compared. This was followed by the evaluation of bonds formed on bond pads having doped SiO2 (low k) as underlying structures. In addition, the effect of varying the percentage of the wire dopant, palladium and bonding process parameters (bonding force, bond time, ultrasonic energy) for 0.8 mil (20 mum) bonding wire was also evaluated. Finally, a degradation empirical model was developed to understand the decrease in the wire strength. This research effort helped to develop a fundamental understanding of the various factors affecting the reliability of a ball bond from a design (low diameter bonding wire), material (low k and bonding wire dopants), and process (wire bonding process parameters) perspective for a first level interconnection technique, namely wire bonding. The significance of this research endeavor was the systematic investigation of the ball bonds formed using 0.8 mil (20 microm) gold bonding wire within the wire bonding arena. This research addressed low k

  1. Microstructural evolution and tensile properties of Sn-Ag-Cu mixed with Sn-Pb solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wang Fengjiang [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States); O' Keefe, Matthew [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States)], E-mail: mjokeefe@mst.edu; Brinkmeyer, Brandon [Department of Materials Science and Engineering and Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65401 (United States)

    2009-05-27

    The effect of incorporating eutectic Sn-Pb solder with Sn-3.0Ag-0.5Cu (SAC) Pb-free solder on the microstructure and tensile properties of the mixed alloys was investigated. Alloys containing 100, 75, 50, 25, 20, 15, 10, 5 and 0 wt% SAC, with the balance being Sn-37Pb eutectic solder alloy, were prepared and characterized. Optical and scanning electron microscopy were used to analyze the microstructures while 'mini-tensile' test specimens were fabricated and tested to determine mechanical properties at the mm length scale, more closely matching that of the solder joints. Microstructural analysis indicated that a Pb-rich phase formed and was uniformly distributed at the boundary between the Sn-rich grains or between the Sn-rich and the intermetallic compounds in the solder. Tensile results showed that mixing of the alloys resulted in an increase in both the yield and the ultimate tensile strength compared to the original solders, with the 50% SAC-50% Sn-Pb mixture having the highest measured strength. Initial investigations indicate the formation and distribution of a Pb-rich phase in the mixed solder alloys as the source of the strengthening mechanism.

  2. Mechanical Deformation Behavior of Sn-Ag-Cu Solders with Minor Addition of 0.05 wt.% Ni

    Science.gov (United States)

    Hammad, A. E.; El-Taher, A. M.

    2014-11-01

    The aim of the present work is to develop a comparative evaluation of the microstructural and mechanical deformation behavior of Sn-Ag-Cu (SAC) solders with the minor addition of 0.05 wt.% Ni. Test results showed that, by adding 0.05Ni element into SAC solders, generated mainly small rod-shaped (Cu,Ni)6Sn5 intermetallic compounds (IMCs) inside the β-Sn phase. Moreover, increasing the Ag content and adding Ni could result in the change of the shape and size of the IMC precipitate. Hence, a significant improvement is observed in the mechanical properties of SAC solders with increasing Ag content and Ni addition. On the other hand, the tensile results of Ni-doped SAC solders showed that both the yield stress and ultimate tensile strengths decrease with increasing temperature and with decreasing strain rate. This behavior was attributed to the competing effects of work hardening and dynamic recovery processes. The Sn-2.0Ag-0.5Cu-0.05Ni solder displayed the highest mechanical properties due to the formation of hard (Cu,Ni)6Sn5 IMCs. Based on the obtained stress exponents and activation energies, it is suggested that the dominant deformation mechanism in SAC (205)-, SAC (0505)- and SAC (0505)-0.05Ni solders is pipe diffusion, and lattice self-diffusion in SAC (205)-0.05Ni solder. In view of these results, the Sn-2.0Ag-0.5Cu-0.05Ni alloy is a more reliable solder alloy with improved properties compared with other solder alloys tested in the present work.

  3. Incorporation of Interfacial Intermetallic Morphology in Fracture Mechanism Map for Sn-Ag-Cu Solder Joints

    Science.gov (United States)

    Huang, Z.; Kumar, P.; Dutta, I.; Sidhu, R.; Renavikar, M.; Mahajan, R.

    2014-01-01

    A fracture mechanism map (FMM) is a powerful tool which correlates the fracture behavior of a material to its microstructural characteristics in an explicit and convenient way. In the FMM for solder joints, an effective thickness of the interfacial intermetallic compound (IMC) layer ( t eff) and the solder yield strength ( σ ys,eff) are used as abscissa and ordinate axes, respectively, as these two predominantly affect the fracture behavior of solder joints. Earlier, a definition of t eff, based on the uniform thickness of IMC ( t u) and the average height of the IMC scallops ( t s), was proposed and shown to aptly explain the fracture behavior of solder joints on Cu. This paper presents a more general definition of t eff that is more widely applicable to a range of metallizations, including Cu and electroless nickel immersion gold (ENIG). Using this new definition of t eff, mode I FMM for SAC387/Cu joints has been updated and its validity was confirmed. A preliminary FMM for SAC387/Cu joints with ENIG metallization is also presented.

  4. The thermodynamic database COST MP0602 for materials for high-temperature lead-free soldering

    Czech Academy of Sciences Publication Activity Database

    Kroupa, Aleš; Dinsdale, A.; Watson, A.; Vřešťál, J.; Zemanová, Adéla; Brož, P.

    2012-01-01

    Roč. 48, č. 3 (2012), s. 339-346 ISSN 1450-5339 R&D Projects: GA MŠk LD11024 Institutional support: RVO:68081723 Keywords : CALPHAD method * lead-free solders * thermodynamic database Subject RIV: BJ - Thermodynamics Impact factor: 1.435, year: 2012

  5. Circuit reliability boosted by soldering pins of disconnect plugs to sockets

    Science.gov (United States)

    Pierce, W. B.

    1964-01-01

    Where disconnect pins must be used for wiring and testing a circuit, improved system reliability is obtained by making a permanent joint between pins and sockets of the disconnect plug. After the circuit has been tested, contact points may be fused through soldering, brazing, or welding.

  6. Maintaining Low Voiding Solder Die Attach for Power Die While Minimizing Die Tilt

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, Randy; Peterson, Kenneth A.

    2015-10-01

    This paper addresses work to minimize voiding and die tilt in solder attachment of a large power die, measuring 9.0 mm X 6.5 mm X 0.1 mm (0.354” x 0.256” x 0.004”), to a heat spreader. As demands for larger high power die continue, minimizing voiding and die tilt is of interest for improved die functionality, yield, manufacturability, and reliability. High-power die generate considerable heat, which is important to dissipate effectively through control of voiding under high thermal load areas of the die while maintaining a consistent bondline (minimizing die tilt). Voiding was measured using acoustic imaging and die tilt was measured using two different optical measurement systems. 80Au-20Sn solder reflow was achieved using a batch vacuum solder system with optimized fixturing. Minimizing die tilt proved to be the more difficult of the two product requirements to meet. Process development variables included tooling, weight and solder preform thickness.

  7. Fatigue damage modeling in solder interconnects using a cohesive zone approach

    NARCIS (Netherlands)

    Abdul-Baqi, A.J.J.; Schreurs, P.J.G.; Geers, M.G.D.

    2005-01-01

    The objective of this work is to model the fatigue damage process in a solder bump subjected to cyclic loading conditions. Fatigue damage is simulated using the cohesive zone methodology. Damage is assumed to occur at interfaces modeled through cohesive zones in the material, while the bulk material

  8. Microstructural and mechanical properties analysis of extruded Sn–0.7Cu solder alloy

    Directory of Open Access Journals (Sweden)

    Abdoul-Aziz Bogno

    2015-01-01

    Full Text Available The properties and performance of lead-free solder alloys such as fluidity and wettability are defined by the alloy composition and solidification microstructure. Rapid solidification of metallic alloys is known to result in refined microstructures with reduced microsegregation and improved mechanical properties of the final products as compared to normal castings. The rapidly solidified Sn-based solders by melt spinning were shown to be suitable for soldering with low temperature and short soldering duration. In the present study, rapidly solidified Sn–0.7 wt.%Cu droplets generated by impulse atomization (IA were achieved as well as directional solidification under transient conditions at lower cooling rate. This paper reports on a comparative study of the rapidly solidified and the directionally solidified samples. Different but complementary characterization techniques were used to fully analyze the solidification microstructures of the samples obtained under the two cooling regimes. These include X-ray diffractometry (XRD and scanning electron microscopy (SEM. In order to compare the tensile strength and elongation to fracture of the directionally solidified ingot and strip castings with the atomized droplet, compaction and extrusion of the latter were carried out. It was shown that more balanced and superior tensile mechanical properties are available for the hot extruded samples from compacted as-atomized Sn–0.7 wt.%Cu droplets. Further, elongation-to-fracture was 2–3× higher than that obtained for the directionally solidified samples.

  9. Development of high melting point, environmentally friendly solders, using the calphad approach

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hald, John; Hattel, Jesper Henri

    2008-01-01

    An attempt has been made using the CALPHAD approach via Thermo-Calc to explore the various possible chemical compositions that adhere to the melting criterion i.e. 270-350 degrees C, required to replace the traditionally used high lead content solders for first level packaging applications. Vario...... tension have also been considered. Special focus has been given to toxicity related issues since the main ideology of looking for an alternative to high lead containing solders is not related to technical issues but due to environmental concerns.......An attempt has been made using the CALPHAD approach via Thermo-Calc to explore the various possible chemical compositions that adhere to the melting criterion i.e. 270-350 degrees C, required to replace the traditionally used high lead content solders for first level packaging applications. Various...... of promising solder alloy candidates. The ternary combinations that satisfied the primary solidification requirement were scrutinized taking into account the commercial interests i.e. availability, cost-effectiveness, recyclability and toxicity issues. Technical issues like manufacturability and surface...

  10. Electrochemical migration of lead-free solder alloys in Na2SO4 environment

    DEFF Research Database (Denmark)

    Medgyes, Balint; Ádám, Sándor; Tar, Lajos

    2017-01-01

    The effect of sulphate ion concentration on electrochemical migration of lead-free solder alloys was investigated with the use of water drop tests, by applying an in-situ optical and electrical inspection system. According to the Mean-Time-To-Failure (MTTF) values it was found that in the case of...

  11. Design and Experiment of a Solder Paste Jetting System Driven by a Piezoelectric Stack

    Directory of Open Access Journals (Sweden)

    Shoudong Gu

    2016-06-01

    Full Text Available To compensate for the insufficiency and instability of solder paste dispensing and printing that are used in the SMT (Surface Mount Technology production process, a noncontact solder paste jetting system driven by a piezoelectric stack based on the principle of the nozzle-needle-system is introduced in this paper, in which a miniscule gap exists between the nozzle and needle during the jetting process. Here, the critical jet ejection velocity is discussed through theoretical analysis. The relations between ejection velocity and needle structure, needle velocity, and nozzle diameter were obtained by FLUENT software. Then, the prototype of the solder paste jetting system was fabricated, and the performance was verified by experiments. The effects of the gap between nozzle and needle, the driving voltage, and the nozzle diameter on the jetting performance and droplet diameter were obtained. Solder paste droplets 0.85 mm in diameter were produced when the gap between the nozzle and needle was adjusted to 10 μm, the driving voltage to 80 V, the nozzle diameter to 0.1 mm, and the variation of the droplet diameter was within ±3%.

  12. Characterizing performances of solder paste printing process at flexible manufacturing lines

    International Nuclear Information System (INIS)

    Siew, Jit Ping; Low, Heng Chin; Teoh, Ping Chow

    2015-01-01

    Solder paste printing (SPP) has been a challenge on printed circuit board (PCB) manufacturing, evident by the proliferation of solder paste inspection equipment, or substituted by rigorous non-value added activity of manual inspections. The objective of this study is to characterize the SPP performance of various products manufactured in flexible production lines with different equipment configurations, and determine areas for process improvement. The study began by collecting information on SPP performance relative to component placement (CP) process, and to the proportion of mixed products. Using a clustering algorithm to group similar elements together, SPP performance across all product-production line pairs are statistically modeled to discover the trend and the influential factors. The main findings are: (a) Ratio of overall dpku for CP and SPP processes are 2:1; (b) logistic regression models of SPP performance indicated that only effects of product-production line and solder paste printer configuration are significant; (c) PCB circuitry design with BGA components and single solder paste printer line configurations generated the highest monthly defects, with the highest variation in the latter

  13. Characterizing performances of solder paste printing process at flexible manufacturing lines

    Energy Technology Data Exchange (ETDEWEB)

    Siew, Jit Ping; Low, Heng Chin [University of Science Malaysia, 11800 Minden, Penang (Malaysia); Teoh, Ping Chow [Wawasan Open University, 54 Jalan Sultan Ahmad Shah, 10050 Penang (Malaysia)

    2015-02-03

    Solder paste printing (SPP) has been a challenge on printed circuit board (PCB) manufacturing, evident by the proliferation of solder paste inspection equipment, or substituted by rigorous non-value added activity of manual inspections. The objective of this study is to characterize the SPP performance of various products manufactured in flexible production lines with different equipment configurations, and determine areas for process improvement. The study began by collecting information on SPP performance relative to component placement (CP) process, and to the proportion of mixed products. Using a clustering algorithm to group similar elements together, SPP performance across all product-production line pairs are statistically modeled to discover the trend and the influential factors. The main findings are: (a) Ratio of overall dpku for CP and SPP processes are 2:1; (b) logistic regression models of SPP performance indicated that only effects of product-production line and solder paste printer configuration are significant; (c) PCB circuitry design with BGA components and single solder paste printer line configurations generated the highest monthly defects, with the highest variation in the latter.

  14. Hypospadias repair using laser tissue soldering (LTS): preliminary results of a prospective randomized study

    Science.gov (United States)

    Kirsch, Andrew J.; Cooper, Christopher S.; Canning, Douglas A.; Snyder, Howard M., III; Zderic, Stephen A.

    1998-07-01

    Purpose: The purpose of this study was to evaluate laser tissue soldering using an 808 nm diode laser and wavelength- matched human albumin solder for urethral surgery in children. Methods: Currently, 30 boys, ages 3 months to 8 years were randomized to standard suturing (n equals 22) or 'sutureless' laser hypospadias repair (n equals 18). Laser soldering was performed with a human albumin solder doped with indocyanine green dye (2.5 mg/ml) using a laser power output of 0.5 W, pulse duration of 0.5 sec, and interval of 0.1 sec. Power density was approximately 16 W/cm2. In the laser group, sutures were used for tissue alignment only. At the time of surgery, neourethral and penile lengths, operative time for urethral repair, and number of sutures/throws were measured. Postoperatively, patients were examined for complications of wound healing, stricture, or fistula formation. Results: Mean age, severity of urethral defect, type of repair, and neourethra length were equivalent between the two groups. Operative time was significantly faster for laser soldering in both simple (1.6 plus or minus 0.21 min, p less than 0.001) and complex (5.4 plus or minus 0.28 min, p less than 0.0001) hypospadias repairs compared to controls (10.6 plus or minus 1.4 min and 27.8 plus or minus 2.9 min, respectively). The mean number of sutures used in the laser group for simple and complex repairs (3.3 plus or minus 0.3 and 8.1 plus or minus 0.64, respectively) were significantly (p less than 0.0001) less than for controls (8.2 plus or minus 0.84 and 20 plus or minus 2.3, respectively). Followup was between 3 months and 14 months. The overall complication rate in the laser group (11%) was lower than the controls (23%). However, statistical significance (p less than 0.05) was achieved only for the subgroup of patients undergoing simple repairs (LTS, 100% success versus suturing, 69% success). Conclusions: These preliminary results indicate that laser tissue soldering for hypospadias repair

  15. Decomposition of no-clean solder flux systems and their effects on the corrosion reliability of electronics

    DEFF Research Database (Denmark)

    Conseil, Helene; Verdingovas, Vadimas; Jellesen, Morten Stendahl

    2016-01-01

    No-clean flux systems are used today for the soldering of electronic printed circuit board assemblies assuming that all the aggressive substances of the flux will vanish during the soldering process i.e. evaporate, decompose or being enclosed safely in the residues. However this is not true in most...... that the fluxes do not decompose fully within the temperature regime of the soldering process, leaving behind significant level of weak organic acid residues. The residue depending on the type and amount can be can be very aggressive towards the corrosion on the printed circuit board assemblies. The glutaric acid...

  16. Fully integrated optical system for lab-on-a-chip applications

    DEFF Research Database (Denmark)

    Balslev, Søren; Olsen, Brian Bilenberg; Geschke, Oliver

    2004-01-01

    We present a lab-on-a-chip device featuring a microfluidic dye laser, wave-guides, microfluidic components and photo-detectors integrated on the chip. The microsystem is designed for wavelength selective absorption measurements in the visible range on a fluidic sample, which can be prepared....../mixed on-chip. The laser structures, wave-guides and micro-fluidic handling system are defined in a single UV-lithography step on a 10 μm thick SU-8 layer on top of the substrate. The SU-8 structures are sealed by a Borofloat glass lid, using polymethylmethacrylate (PMMA) adhesive bonding....

  17. Preservation of forest wood chips

    Energy Technology Data Exchange (ETDEWEB)

    Kofman, P.D.; Thomsen, I.M.; Ohlsson, C.; Leer, E.; Ravn Schmidt, E.; Soerensen, M.; Knudsen, P.

    1999-01-01

    As part of the Danish Energy Research Programme on biomass utilisation for energy production (EFP), this project concerns problems connected to the handling and storing of wood chips. In this project, the possibility of preserving wood chips of the Norway Spruce (Picea Abies) is addressed, and the potential improvements by anaerobic storage are tested. Preservation of wood chips aims at reducing dry matter losses from extensive heating during storage and to reduce production of fungal spores. Fungal spores pose a health hazards to workers handling the chips. Further the producers of wood chips are interested in such a method since it would enable them to give a guarantee for the delivery of homogeneous wood chips also during the winter period. Three different types of wood chips were stored airtight and further one of these was stored in accordance with normal practise and use as reference. The results showed that airtight storage had a beneficial impact on the quality of the chips: no redistribution of moisture, low dry matter losses, unfavourable conditions for microbial activity of most fungi, and the promotion of yeasts instead of fungi with airborne spores. Likewise the firing tests showed that no combustion problems, and no increased risk to the environment or to the health of staff is caused by anaerobic storage of wood chips. In all, the tests of the anaerobic storage method of forest wood chips were a success and a large-scale test of the method will be carried out in 1999. (au)

  18. Integration of microelectronic chips in microfluidic systems on printed circuit board

    International Nuclear Information System (INIS)

    Burdallo, I; Jimenez-Jorquera, C; Fernández-Sánchez, C; Baldi, A

    2012-01-01

    A new scheme for the integration of small semiconductor transducer chips with microfluidic structures on printed circuit board (PCB) is presented. The proposed approach is based on a packaging technique that yields a large and flat area with small and shallow (∼44 µm deep) openings over the chips. The photocurable encapsulant material used, based on a diacrylate bisphenol A polymer, enables irreversible bonding of polydimethylsiloxane microfluidic structures at moderate temperatures (80 °C). This integration scheme enables the insertion of transducer chips in microfluidic systems with a lower added volume than previous schemes. Leakage tests have shown that the bonded structures withstand more than 360 kPa of pressure. A prototype microfluidic system with two detection chips, including one inter-digitated electrode (IDE) chip for conductivity and one ion selective field effect transistor (ISFET) chip for pH, has been implemented and characterized. Good electrical insulation of the chip contacts and silicon edge surfaces from the solution in the microchannels has been achieved. This integration procedure opens the door to the low-cost fabrication of complex analytical microsystems that combine the extraordinary potential of both the microfluidics and silicon microtechnology fields. (paper)

  19. Physics-based process modeling, reliability prediction, and design guidelines for flip-chip devices

    Science.gov (United States)

    Michaelides, Stylianos

    Flip Chip on Board (FCOB) and Chip-Scale Packages (CSPs) are relatively new technologies that are being increasingly used in the electronic packaging industry. Compared to the more widely used face-up wirebonding and TAB technologies, flip-chips and most CSPs provide the shortest possible leads, lower inductance, higher frequency, better noise control, higher density, greater input/output (I/O), smaller device footprint and lower profile. However, due to the short history and due to the introduction of several new electronic materials, designs, and processing conditions, very limited work has been done to understand the role of material, geometry, and processing parameters on the reliability of flip-chip devices. Also, with the ever-increasing complexity of semiconductor packages and with the continued reduction in time to market, it is too costly to wait until the later stages of design and testing to discover that the reliability is not satisfactory. The objective of the research is to develop integrated process-reliability models that will take into consideration the mechanics of assembly processes to be able to determine the reliability of face-down devices under thermal cycling and long-term temperature dwelling. The models incorporate the time and temperature-dependent constitutive behavior of various materials in the assembly to be able to predict failure modes such as die cracking and solder cracking. In addition, the models account for process-induced defects and macro-micro features of the assembly. Creep-fatigue and continuum-damage mechanics models for the solder interconnects and fracture-mechanics models for the die have been used to determine the reliability of the devices. The results predicted by the models have been successfully validated against experimental data. The validated models have been used to develop qualification and test procedures for implantable medical devices. In addition, the research has helped develop innovative face

  20. Thermal Fatigue Evaluation of Pb-Free Solder Joints: Results, Lessons Learned, and Future Trends

    Science.gov (United States)

    Coyle, Richard J.; Sweatman, Keith; Arfaei, Babak

    2015-09-01

    Thermal fatigue is a major source of failure of solder joints in surface mount electronic components and it is critically important in high reliability applications such as telecommunication, military, and aeronautics. The electronic packaging industry has seen an increase in the number of Pb-free solder alloy choices beyond the common near-eutectic Sn-Ag-Cu alloys first established as replacements for eutectic SnPb. This paper discusses the results from Pb-free solder joint reliability programs sponsored by two industry consortia. The characteristic life in accelerated thermal cycling is reported for 12 different Pb-free solder alloys and a SnPb control in 9 different accelerated thermal cycling test profiles in terms of the effects of component type, accelerated thermal cycling profile and dwell time. Microstructural analysis on assembled and failed samples was performed to investigate the effect of initial microstructure and its evolution during accelerated thermal cycling test. A significant finding from the study is that the beneficial effect of Ag on accelerated thermal cycling reliability (measured by characteristic lifetime) diminishes as the severity of the accelerated thermal cycling, defined by greater ΔT, higher peak temperature, and longer dwell time increases. The results also indicate that all the Pb-free solders are more reliable in accelerated thermal cycling than the SnPb alloy they have replaced. Suggestions are made for future work, particularly with respect to the continued evolution of alloy development for emerging application requirements and the value of using advanced analytical methods to provide a better understanding of the effect of microstructure and its evolution on accelerated thermal cycling performance.

  1. Understanding Bonds - Denmark

    DEFF Research Database (Denmark)

    Rimmer, Nina Røhr

    2016-01-01

    Undervisningsmateriale. A bond is a debt security, similar to an ”I Owe You document” (IOU). When you purchase a bond, you are lending money to a government, municipality, corporation, federal agency or other entity known as the issuer. In return for the loan, the issuer promises to pay you...... a specified rate of interest during the life of the bond and to repay the face value of the bond (the principal) when it “matures,” or comes due. Among the types of bonds you can choose from are: Government securities, municipal bonds, corporate bonds, mortgage and asset-backed securities, federal agency...... securities and foreign government bonds....

  2. Amdahl 470 Chip Package

    CERN Multimedia

    1975-01-01

    In the late 70s the larger IBM computers were water cooled. Amdahl, an IBM competitor, invented an air cooling technology for it's computers. His company worked hard, developing a computer that was faster and less expensive than the IBM System/360 mainframe computer systems. This object contains an actual Amdahl series 470 computer logic chip with an air cooling device mounted on top. The package leads and cooling tower are gold-plated.

  3. Ultra-thin silicon (UTSi) on insulator CMOS transceiver and time-division multiplexed switch chips for smart pixel integration

    Science.gov (United States)

    Zhang, Liping; Sawchuk, Alexander A.

    2001-12-01

    We describe the design, fabrication and functionality of two different 0.5 micron CMOS optoelectronic integrated circuit (OEIC) chips based on the Peregrine Semiconductor Ultra-Thin Silicon on insulator technology. The Peregrine UTSi silicon- on-sapphire (SOS) technology is a member of the silicon-on- insulator (SOI) family. The low-loss synthetic sapphire substrate is optically transparent and has good thermal conductivity and coefficient of thermal expansion properties, which meet the requirements for flip-chip bonding of VCSELs and other optoelectronic input-output components. One chip contains transceiver and network components, including four channel high-speed CMOS transceiver modules, pseudo-random bit stream (PRBS) generators, a voltage controlled oscillator (VCO) and other test circuits. The transceiver chips can operate in both self-testing mode and networking mode. An on- chip clock and true-single-phase-clock (TSPC) D-flip-flop have been designed to generate a PRBS at over 2.5 Gb/s for the high-speed transceiver arrays to operate in self-testing mode. In the networking mode, an even number of transceiver chips forms a ring network through free-space or fiber ribbon interconnections. The second chip contains four channel optical time-division multiplex (TDM) switches, optical transceiver arrays, an active pixel detector and additional test devices. The eventual applications of these chips will require monolithic OEICs with integrated optical input and output. After fabrication and testing, the CMOS transceiver array dies will be packaged with 850 nm vertical cavity surface emitting lasers (VCSELs), and metal-semiconductor- metal (MSM) or GaAs p-i-n detector die arrays to achieve high- speed optical interconnections. The hybrid technique could be either wire bonding or flip-chip bonding of the CMOS SOS smart-pixel arrays with arrays of VCSELs and photodetectors onto an optoelectronic chip carrier as a multi-chip module (MCM).

  4. Silicon Chip-to-Chip Mode-Division Multiplexing

    DEFF Research Database (Denmark)

    Baumann, Jan Markus; Porto da Silva, Edson; Ding, Yunhong

    2018-01-01

    A chip-to-chip mode-division multiplexing connection is demonstrated using a pair of multiplexers/demultiplexers fabricated on the silicon-on-insulator platform. Successful mode multiplexing and demultiplexing is experimentally demonstrated, using the LP01, LP11a and LP11b modes.......A chip-to-chip mode-division multiplexing connection is demonstrated using a pair of multiplexers/demultiplexers fabricated on the silicon-on-insulator platform. Successful mode multiplexing and demultiplexing is experimentally demonstrated, using the LP01, LP11a and LP11b modes....

  5. Subgrain Rotation Behavior in Sn3.0Ag0.5Cu-Sn37Pb Solder Joints During Thermal Shock

    Science.gov (United States)

    Han, Jing; Tan, Shihai; Guo, Fu

    2018-01-01

    Ball grid array (BGA) samples were soldered on a printed circuit board with Sn37Pb solder paste to investigate the recrystallization induced by subgrain rotation during thermal shock. The composition of the solder balls was Sn3.0Ag0.5Cu-Sn37Pb, which comprised mixed solder joints. The BGA component was cross-sectioned before thermal shock. The microstructure and grain orientations were obtained by a scanning electron microscope equipped with an electron back-scattered diffraction system. Two mixed solder joints at corners of the BGA component were selected as the subjects. The results showed that recrystallization occurred at the corner of the solder joints after 200 thermal shock cycles. The recrystallized subgrains had various new grain orientations. The newly generated grain orientations were closely related to the initial grain orientations, which indicated that different subgrain rotation behaviors could occur in one mixed solder joint with the same initial grain orientation. When the misorientation angles were very small, the rotation axes were about Sn [100], [010] and [001], as shown by analyzing the misorientation angles and subgrain rotation axes, while the subgrain rotation behavior with large misorientation angles in the solder joints was much more complicated. As Pb was contained in the solder joints and the stress was concentrated on the corner of the mixed solder joints, concaves and cracks were formed. When the adjacent recrystallized subgrains were separated, and the process of the continuous recrystallization was limited.

  6. Wire bonding in microelectronics

    CERN Document Server

    Harman, George G

    2010-01-01

    Wire Bonding in Microelectronics, Third Edition, has been thoroughly revised to help you meet the challenges of today's small-scale and fine-pitch microelectronics. This authoritative guide covers every aspect of designing, manufacturing, and evaluating wire bonds engineered with cutting-edge techniques. In addition to gaining a full grasp of bonding technology, you'll learn how to create reliable bonds at exceedingly high yields, test wire bonds, solve common bonding problems, implement molecular cleaning methods, and much more. Coverage includes: Ultrasonic bonding systems and technologies, including high-frequency systems Bonding wire metallurgy and characteristics, including copper wire Wire bond testing Gold-aluminum intermetallic compounds and other interface reactions Gold and nickel-based bond pad plating materials and problems Cleaning to improve bondability and reliability Mechanical problems in wire bonding High-yield, fine-pitch, specialized-looping, soft-substrate, and extreme-temperature wire bo...

  7. The effect of intermetallic compound morphology on Cu diffusion in Sn-Ag and Sn-Pb solder bump on the Ni/Cu Under-bump metallization

    Science.gov (United States)

    Jang, Guh-Yaw; Duh, Jenq-Gong

    2005-01-01

    The eutectic Sn-Ag solder alloy is one of the candidates for the Pb-free solder, and Sn-Pb solder alloys are still widely used in today’s electronic packages. In this tudy, the interfacial reaction in the eutectic Sn-Ag and Sn-Pb solder joints was investigated with an assembly of a solder/Ni/Cu/Ti/Si3N4/Si multilayer structures. In the Sn-3.5Ag solder joints reflowed at 260°C, only the (Ni1-x,Cux)3Sn4 intermetallic compound (IMC) formed at the solder/Ni interface. For the Sn-37Pb solder reflowed at 225°C for one to ten cycles, only the (Ni1-x,Cux)3Sn4 IMC formed between the solder and the Ni/Cu under-bump metallization (UBM). Nevertheless, the (Cu1-y,Niy)6Sn5 IMC was observed in joints reflowed at 245°C after five cycles and at 265°C after three cycles. With the aid of microstructure evolution, quantitative analysis, and elemental distribution between the solder and Ni/Cu UBM, it was revealed that Cu content in the solder near the solder/IMC interface played an important role in the formation of the (Cu1-y,Niy)6Sn5 IMC. In addition, the diffusion behavior of Cu in eutectic Sn-Ag and Sn-Pb solders with the Ni/Cu UBM were probed and discussed. The atomic flux of Cu diffused through Ni was evaluated by detailed quantitative analysis in an electron probe microanalyzer (EPMA). During reflow, the atomic flux of Cu was on the order of 1016-1017 atoms/cm2sec in both the eutectic Sn-Ag and Sn-Pb systems.

  8. Effect of rare earth Ce on the fatigue life of SnAgCu solder joints in WLCSP device using FEM and experiments

    International Nuclear Information System (INIS)

    Zhang, Liang; Han, Ji-guang; Guo, Yong-huan; He, Cheng-wen

    2014-01-01

    With the addition of 0.03 wt% rare earth Ce, in our previous works, the properties of SnAgCu solder were enhanced obviously. Based on the Garofalo–Arrhenius creep constitutive model, finite element method was used to simulate the stress–strain response during thermal cycle loading, and combined with the fatigue life prediction models, the fatigue life of SnAgCu/SnAgCuCe solder joints was calculated respectively, which can demonstrate the effect of the rare earth Ce on the fatigue life of SnAgCu solder joints. The results indicated that the maximum stress–strain can be found on the top surface of the corner solder joint, and the warpage of the PCB substrate occurred during thermal cycle loading. The trends obtained from modeling results have a good agreement with the experimental data reported in the literature for WLCSP devices. In addition, the stress–strain of SnAgCuCe solder joints is lower than that of SnAgCu solder joints. The thermal fatigue lives of solder joints calculated based on the creep model and creep strain energy density model show that the fatigue life of SnAgCuCe solder joints is higher than the SnAgCu solder joints. The fatigue life of SnAgCuCe solder joints can be enhanced significantly with the addition of Ce, is 30.2% higher than that of SnAgCu solder joints, which can be attributed to the CeSn 3 particles formed resisting the motion of dislocation; moreover, the refinement of microstructure and the IMC sizes also contribute to the enhancement of fatigue life, which elucidates that SnAgCuCe solder can be utilized in electronic industry with high reliability replacing the SnAgCu solder

  9. The Effect of Reflow on Wettability of Sn 96.5 Ag 3 Cu 0.5 Solder

    Directory of Open Access Journals (Sweden)

    Zoltán Weltsch

    2012-11-01

    Full Text Available Surface conditions on Printed Circuit Board (PCB final finishes have an important impact on the wetting behaviour with lead-free solder. The improvement of wettability in liquid Sn 96.5 Ag 3 Cu 0.5 Solder alloy on PCB substrate was measured with a sessile drop method at 523 K temperature. Wetting properties was determined in normal atmospheric air and inert atmosphere. The wetting angles increasing with the number of reflows both atmosphere. The effect of the atmosphere has a huge importance of the oxidation which manifests itself of the measured wetting angles. One of the most important factors to the wetting properties is the amount of oxygen in the soldering atmosphere. Using the inert atmosphere is crucial to Pb-free solders, particularly after reflows.

  10. Evaluation of Ferrite Chip Beads as Surge Current Limiters in Circuits with Tantalum Capacitors

    Science.gov (United States)

    Teverovsky, Alexander

    2014-01-01

    Limiting resistors are currently required to be connected in series with tantalum capacitors to reduce the risk of surge current failures. However, application of limiting resistors decreases substantially the efficiency of the power supply systems. An ideal surge current limiting device should have a negligible resistance for DC currents and high resistance at frequencies corresponding to transients in tantalum capacitors. This work evaluates the possibility of using chip ferrite beads (FB) as such devices. Twelve types of small size FBs from three manufacturers were used to evaluate their robustness under soldering stresses and at high surge current spikes associated with transients in tantalum capacitors. Results show that FBs are capable to withstand current pulses that are substantially greater than the specified current limits. However, due to a sharp decrease of impedance with current, FBs do not reduce surge currents to the required level that can be achieved with regular resistors.

  11. Diffusion barrier characteristics and shear fracture behaviors of eutectic PbSn solder/electroless Co(W,P) samples

    International Nuclear Information System (INIS)

    Pan, Hung-Chun; Hsieh, Tsung-Eong

    2012-01-01

    Highlights: ► Diffusion barrier features, activation energies of IMC growth and mechanical behaviors of electroless Co(W,P)/PbSn joints. ► Amorphous Co(W,P) is a sacrificial- plus stuffed-type barrier while polycrystalline Co(W,P) is a sacrificial-type barrier. ► Ductile mode dominates the failure of Co(W,P)/PbSn joints. ► Phosphorus content of Co(W,P) is crucial to the barrier capability and microstructure evolution at Co(W,P)/PbSn interface. ► Diffusion barrier capability is governed by the nature of chemical bonds, rather than the crystallinity of materials. - Abstract: Diffusion barrier characteristics, activation energy (E a ) of IMC growth and bonding properties of amorphous and polycrystalline electroless Co(W,P) (termed as α-Co(W,P) and poly-Co(W,P)) to eutectic PbSn solder are presented. Intermetallic compound (IMC) spallation and an nano-crystalline P-rich layer were observed in PbSn/α-Co(W,P) samples subjected to liquid-state aging at 250 °C. In contrast, IMCs resided on the P-rich layer in PbSn/α-Co(W,P) samples subjected to solid-state aging at 150 °C. Thick IMCs neighboring to an amorphous W-rich layer was seen in PbSn/poly-Co(W,P) samples regardless of the aging type. α-Co(W,P) was found to be a sacrificial- plus stuffed-type barrier while poly-Co(W,P) is mainly a sacrificial-type barrier. The values of E a 's for PbSn/α-Co(W,P) and PbSn/poly-Co(W,P) systems were 338.6 and 167.5 kJ/mol, respectively. Shear test revealed the ductile mode dominates the failure in both α- and poly-Co(W,P) samples. Analytical results indicated the high P content in electroless layer might enhance the barrier capability but degrade the bonding strength.

  12. Incorporation of in-plane interconnects to reflow bonding for electrical functionality

    International Nuclear Information System (INIS)

    Moğulkoç, B; Jansen, H V; Ter Brake, H J M; Elwenspoek, M C

    2011-01-01

    Incorporation of in-plane electrical interconnects to reflow bonding is studied to provide electrical functionality to lab-on-a-chip or microfluidic devices. Reflow bonding is the packaging technology, in which glass tubes are joined to silicon substrates at elevated temperatures. The tubes are used to interface the silicon-based fluidic devices and are directly compatible with standard Swagelok® connectors. After the bonding, the electrically conductive lines will allow probing into the volume confined by the tube, where the fluidic device operates. Therefore methods for fabricating electrical interconnects that survive the bonding procedure at elevated temperature and do not alter the properties of the bond interface are investigated

  13. Microstructural discovery of Al addition on Sn–0.5Cu-based Pb-free solder design

    International Nuclear Information System (INIS)

    Koo, Jahyun; Lee, Changsoo; Hong, Sung Jea; Kim, Keun-Soo; Lee, Hyuck Mo

    2015-01-01

    It is important to develop Pb-free solder alloys suitable for automotive use instead of traditional Sn–Pb solder due to environmental regulations (e.g., Restriction of Hazardous Substances (RoHS)). Al addition has been spotlighted to enhance solder properties. In this study, we investigated the microstructural change of Sn–0.5Cu wt.% based Pb-free solder alloys with Al addition (0.01–0.05 wt.%). The small amount of Al addition caused a remarkable microstructural change. The Al was favored to form Cu–Al intermetallic compounds inside the solder matrix. We identified the Cu–Al intermetallic compound as Cu_3_3Al_1_7, which has a rhombohedral structure, using EPMA and TEM analyses. This resulted in refined Cu_6Sn_5 networks in the Sn–0.5Cu based solder alloy. In addition, we conducted thermal analysis to confirm its stability at a high temperature of approximately 230 °C, which is the necessary temperature range for automotive applications. The solidification results were substantiated thermodynamically using the Scheil solidification model. We can provide criteria for the minimum aluminum content to modify the microstructure of Pb-free solder alloys. - Graphical abstract: The minor Al additions refined eutectic Cu_6Sn_5 IMC networks on the Sn–0.5Cu based solder alloys. The microstructure was dramatically changed with the minor Al addition. - Highlights: • We observed dramatic microstructure-change with Al additions. • We defined Cu_3_3Al_1_7 IMC with Al additions using TEM analysis. • We investigated grain refinement with Al additions using EBSD. • We discussed the refinement based on Scheil solidification model.

  14. A FPGA implementation of solder paste deposit on printed circuit boards errors detector based in a bright and contrast algorithm

    OpenAIRE

    De Luca-Pennacchia, A.; Sánchez-Martínez, M. Á.

    2007-01-01

    Solder paste deposit on printed circuit boards (PCB) is a critical stage. It is known that about 60% of functionality defects in this type of boards are due to poor solder paste printing. These defects can be diminished by means of automatic optical inspection of this printing. Actually, this process is implemented by image processing software with its inherent high computational time cost. In this paper we propose to implement a high parallel degree image comparison algorithm suitable to be ...

  15. Microstructural discovery of Al addition on Sn–0.5Cu-based Pb-free solder design

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Jahyun; Lee, Changsoo [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of); Hong, Sung Jea [MK Electron Co., Ltd., Yongin Cheoin-gu 316-2 (Korea, Republic of); Kim, Keun-Soo, E-mail: keunsookim@hoseo.edu [Department of Display Engineering, Hoseo University, Asan 336-795 (Korea, Republic of); Lee, Hyuck Mo, E-mail: hmlee@kaist.ac.kr [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of)

    2015-11-25

    It is important to develop Pb-free solder alloys suitable for automotive use instead of traditional Sn–Pb solder due to environmental regulations (e.g., Restriction of Hazardous Substances (RoHS)). Al addition has been spotlighted to enhance solder properties. In this study, we investigated the microstructural change of Sn–0.5Cu wt.% based Pb-free solder alloys with Al addition (0.01–0.05 wt.%). The small amount of Al addition caused a remarkable microstructural change. The Al was favored to form Cu–Al intermetallic compounds inside the solder matrix. We identified the Cu–Al intermetallic compound as Cu{sub 33}Al{sub 17}, which has a rhombohedral structure, using EPMA and TEM analyses. This resulted in refined Cu{sub 6}Sn{sub 5} networks in the Sn–0.5Cu based solder alloy. In addition, we conducted thermal analysis to confirm its stability at a high temperature of approximately 230 °C, which is the necessary temperature range for automotive applications. The solidification results were substantiated thermodynamically using the Scheil solidification model. We can provide criteria for the minimum aluminum content to modify the microstructure of Pb-free solder alloys. - Graphical abstract: The minor Al additions refined eutectic Cu{sub 6}Sn{sub 5} IMC networks on the Sn–0.5Cu based solder alloys. The microstructure was dramatically changed with the minor Al addition. - Highlights: • We observed dramatic microstructure-change with Al additions. • We defined Cu{sub 33}Al{sub 17} IMC with Al additions using TEM analysis. • We investigated grain refinement with Al additions using EBSD. • We discussed the refinement based on Scheil solidification model.

  16. THE POSSIBILITY OF USING LASER-ULTRASOUND TO MONITOR THE QUALITY SOLDERED CONNECTIONS CHAMBERS OF LIQUID ROCKET ENGINES

    Directory of Open Access Journals (Sweden)

    N. V. Astredinova

    2014-01-01

    Full Text Available During the manufacturing process to the design of modern liquid rocket engines are presented important requirements, such as minimum weight, maximum stiffness and strength of nodes, maximum service life in operation, high reliability and quality of soldered and welded seams. Due to the high quality requirements soldered connections and the specific design of the nozzle, it became necessary in the development and testing of a new non-conventional non-destructive testing method – laser-ultrasound diagnosis. In accordance with regulatory guidelines, quality control soldered connections is allowed to use an acoustic kind of control methods of the reflected light, transmitted light, resonant, free vibration and acoustic emission. Attempts to use traditional methods of non-destructive testing did not lead to positive results. This is due primarily to the size of typical solder joint defects, as well as the structural features of the rocket engine, the data structure is not controllable. In connection with this, a new method that provides quality control soldered connections cameras LRE based on the thermo generation of ultrasound. Methods of ultrasonic flaw detection of photoacoustic effect, in most cases, have a number of advantages over methods that use standard (traditional piezo transducers. In the course of studies have found that the sensitivity of the laser-ultrasonic method and flaw detector UDL-2M can detect lack of adhesion in the solder joints on the upper edges of the nozzle in the sub-header area of the site.

  17. Effect of trace elements on the interface reactions between two lead-free solders and copper or nickel substrates

    Directory of Open Access Journals (Sweden)

    Soares D.

    2007-01-01

    Full Text Available Traditional Sn-Pb solder alloys are being replaced, because of environmental and health concerns about lead toxicity. Among some alternative alloy systems, the Sn-Zn and Sn-Cu base alloy systems have been studied and reveal promising properties. The reliability of a solder joint is affected by the solder/substrate interaction and the nature of the layers formed at the interface. The solder/substrate reactions, for Sn-Zn and Sn-Cu base solder alloys, were evaluated in what concerns the morphology and chemical composition of the interface layers. The effect of the addition of P, at low levels, on the chemical composition of the layers present at the interface was studied. The phases formed at the interface between the Cu or Ni substrate and a molten lead-free solder at 250ºC, were studied for different stage times and alloy compositions. The melting temperatures, of the studied alloys, were determined by Differential Scanning Calorimetry (DSC. Identification of equilibrium phases formed at the interface layer, and the evaluation of their chemical composition were performed by Scanning Electron Microscopy (SEM/EDS. Different interface characteristics were obtained, namely for the alloys containing Zn. The obtained IML layer thickness was compared, for both types of alloy systems.

  18. Effects of Ag addition on solid–state interfacial reactions between Sn–Ag–Cu solder and Cu substrate

    International Nuclear Information System (INIS)

    Yang, Ming; Ko, Yong-Ho; Bang, Junghwan; Kim, Taek-Soo; Lee, Chang-Woo; Li, Mingyu

    2017-01-01

    Low–Ag–content Sn–Ag–Cu (SAC) solders have attracted much recent attention in electronic packaging for their low cost. To reasonably reduce the Ag content in Pb–free solders, a deep understanding of the basic influence of Ag on the SAC solder/Cu substrate interfacial reaction is essential. Previous studies have discussed the influence of Ag on the interfacial intermetallic compound (IMC) thickness. However, because IMC growth is the joint result of multiple factors, such characterizations do not reveal the actual role of Ag. In this study, changes in interfacial IMCs after Ag introduction were systemically and quantitatively characterized in terms of coarsening behaviors, orientation evolution, and growth kinetics. The results show that Ag in the solder alloy affects the coarsening behavior, accelerates the orientation concentration, and inhibits the growth of interfacial IMCs during solid–state aging. The inhibition mechanism was quantitatively discussed considering the individual diffusion behaviors of Cu and Sn atoms, revealing that Ag inhibits interfacial IMC growth primarily by slowing the diffusion of Cu atoms through the interface. - Highlights: •Role of Ag in IMC formation during Sn–Ag–Cu soldering was investigated. •Ag affects coarsening, crystallographic orientation, and IMC growth. •Diffusion pathways of Sn and Cu are affected differently by Ag. •Ag slows Cu diffusion to inhibit IMC growth at solder/substrate interface.

  19. Effects of Ag addition on solid–state interfacial reactions between Sn–Ag–Cu solder and Cu substrate

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ming [Micro-Joining Center, Korea Institute of Industrial Technology (KITECH), Incheon 21999 (Korea, Republic of); Ko, Yong-Ho [Micro-Joining Center, Korea Institute of Industrial Technology (KITECH), Incheon 21999 (Korea, Republic of); Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291, Daehak-ro, Yuseong-gu, Daejeon 34141 (Korea, Republic of); Bang, Junghwan [Micro-Joining Center, Korea Institute of Industrial Technology (KITECH), Incheon 21999 (Korea, Republic of); Kim, Taek-Soo [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291, Daehak-ro, Yuseong-gu, Daejeon 34141 (Korea, Republic of); Lee, Chang-Woo, E-mail: cwlee@kitech.re.kr [Micro-Joining Center, Korea Institute of Industrial Technology (KITECH), Incheon 21999 (Korea, Republic of); Li, Mingyu, E-mail: myli@hit.edu.cn [Shenzhen Key Laboratory of Advanced Materials, Harbin Institute of Technology Shenzhen Graduate School, Shenzhen 518055 (China)

    2017-02-15

    Low–Ag–content Sn–Ag–Cu (SAC) solders have attracted much recent attention in electronic packaging for their low cost. To reasonably reduce the Ag content in Pb–free solders, a deep understanding of the basic influence of Ag on the SAC solder/Cu substrate interfacial reaction is essential. Previous studies have discussed the influence of Ag on the interfacial intermetallic compound (IMC) thickness. However, because IMC growth is the joint result of multiple factors, such characterizations do not reveal the actual role of Ag. In this study, changes in interfacial IMCs after Ag introduction were systemically and quantitatively characterized in terms of coarsening behaviors, orientation evolution, and growth kinetics. The results show that Ag in the solder alloy affects the coarsening behavior, accelerates the orientation concentration, and inhibits the growth of interfacial IMCs during solid–state aging. The inhibition mechanism was quantitatively discussed considering the individual diffusion behaviors of Cu and Sn atoms, revealing that Ag inhibits interfacial IMC growth primarily by slowing the diffusion of Cu atoms through the interface. - Highlights: •Role of Ag in IMC formation during Sn–Ag–Cu soldering was investigated. •Ag affects coarsening, crystallographic orientation, and IMC growth. •Diffusion pathways of Sn and Cu are affected differently by Ag. •Ag slows Cu diffusion to inhibit IMC growth at solder/substrate interface.

  20. Rapid Solidification of Sn-Cu-Al Alloys for High-Reliability, Lead-Free Solder: Part II. Intermetallic Coarsening Behavior of Rapidly Solidified Solders After Multiple Reflows

    Science.gov (United States)

    Reeve, Kathlene N.; Choquette, Stephanie M.; Anderson, Iver E.; Handwerker, Carol A.

    2016-12-01

    Controlling the size, dispersion, and stability of intermetallic compounds in lead-free solder alloys is vital to creating reliable solder joints regardless of how many times the solder joints are melted and resolidified (reflowed) during circuit board assembly. In this article, the coarsening behavior of Cu x Al y and Cu6Sn5 in two Sn-Cu-Al alloys, a Sn-2.59Cu-0.43Al at. pct alloy produced via drip atomization and a Sn-5.39Cu-1.69Al at. pct alloy produced via melt spinning at a 5-m/s wheel speed, was characterized after multiple (1-5) reflow cycles via differential scanning calorimetry between the temperatures of 293 K and 523 K (20 °C and 250 °C). Little-to-no coarsening of the Cu x Al y particles was observed for either composition; however, clustering of Cu x Al y particles was observed. For Cu6Sn5 particle growth, a bimodal size distribution was observed for the drip atomized alloy, with large, faceted growth of Cu6Sn5 observed, while in the melt spun alloy, Cu6Sn5 particles displayed no significant increase in the average particle size, with irregularly shaped, nonfaceted Cu6Sn5 particles observed after reflow, which is consistent with shapes observed in the as-solidified alloys. The link between original alloy composition, reflow undercooling, and subsequent intermetallic coarsening behavior was discussed by using calculated solidification paths. The reflowed microstructures suggested that the heteroepitaxial relationship previously observed between the Cu x Al y and the Cu6Sn5 was maintained for both alloys.

  1. Significance of wood extractives for wood bonding.

    Science.gov (United States)

    Roffael, Edmone

    2016-02-01

    Wood contains primary extractives, which are present in all woods, and secondary extractives, which are confined in certain wood species. Extractives in wood play a major role in wood-bonding processes, as they can contribute to or determine the bonding relevant properties of wood such as acidity and wettability. Therefore, extractives play an immanent role in bonding of wood chips and wood fibres with common synthetic adhesives such as urea-formaldehyde-resins (UF-resins) and phenol-formaldehyde-resins (PF-resins). Extractives of high acidity accelerate the curing of acid curing UF-resins and decelerate bonding with alkaline hardening PF-resins. Water-soluble extractives like free sugars are detrimental for bonding of wood with cement. Polyphenolic extractives (tannins) can be used as a binder in the wood-based industry. Additionally, extractives in wood can react with formaldehyde and reduce the formaldehyde emission of wood-based panels. Moreover, some wood extractives are volatile organic compounds (VOC) and insofar also relevant to the emission of VOC from wood and wood-based panels.

  2. Experiment list: SRX122496 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available || chip antibody=Rel || treatment=LPS || time=120 min || chip antibody manufacturer 1=Santa Cruz || chip ant...ibody catalog number 1=sc-71 || chip antibody manufacturer 2=Santa Cruz || chip antibody catalog number 2=sc

  3. Effect of surface oxide on the melting behavior of lead-free solder nanowires and nanorods

    International Nuclear Information System (INIS)

    Gao Fan; Rajathurai, Karunaharan; Cui, Qingzhou; Zhou, Guangwen; NkengforAcha, Irene; Gu Zhiyong

    2012-01-01

    Lead-free nanosolders have shown promise in nanowire and nanoelectronics assembly. Among various important parameters, melting is the most fundamental property affecting the assembly process. Here we report that the melting behavior of tin and tin/silver nanowires and nanorods can be significantly affected by the surface oxide of nanosolders. By controlling the nanosolder reflow atmosphere using a flux, the surface oxide of the nanowires/nanorods can be effectively removed and complete nanosolder melting can be achieved. The complete melting of the nanosolders leads to the formation of nanoscale to microscale spherical solder balls, followed by Ostwald ripening phenomenon. The contact angle of the microscale solder balls formed on Si substrate was measured by direct electron microscopic imaging. These results provide new insights into micro- and nanoscale phase transition and liquid droplet coalescence from nanowires/nanorods to spheroids, and are relevant to nanoscale assembly and smaller ball grid array formation.

  4. Recovery of Tin and Nitric Acid from Spent Solder Stripping Solutions

    International Nuclear Information System (INIS)

    Ahn, Jae-Woo; Ryu, Seong-Hyung; Kim, Tae-young

    2015-01-01

    Spent solder-stripping solutions containing tin, copper, iron, and lead in nitric acid solution, are by-products of the manufacture of printed-circuit boards. The recovery of these metals and the nitric acid, for re-use has economic and environmental benefits. In the spent solder-stripping solution, a systematic method to determine a suitable process for recovery of valuable metals and nitric acid was developed. Initially, more than 90% of the tin was successfully recovered as high-purity SnO 2 by thermal precipitation at 80 ℃ for 3 hours. About 94% of the nitric acid was regenerated effectively from the spent solutions by diffusion dialysis, after which there remained copper, iron, and lead in solution. Leakage of tin through the anion-exchange membrane was the lowest (0.026%), whereas Pb-leakage was highest (4.26%). The concentration of the regenerated nitric acid was about 5.1 N.

  5. Appendix to the report from the low-residue soldering task force: Phase 2 results

    Energy Technology Data Exchange (ETDEWEB)

    Iman, R.L.; Anderson, D.J.; Huffman, D.D. [and others

    1995-12-01

    The LRSTF report for Phase I of its evaluation of low-residue soldering was issued in June 1995. This Appendix summarizes the results of follow-on testing performed in Phase II and compares electrical test results for both phases. Deliberate decisions were made by the LRSTF in Phase I to challenge the design guideline limits in MILSTD-275, Printed Wiring for Electronic Equipment The LRSTF considered this approach to produce a ``worst case`` design and provide useful information about the robustness of LR soldering processes. As such, good design practices were sometimes deliberately violated in designing the LRSTF board. This approach created some anomalies for both LR boards and RMA/cleaned controls. Phase II testing verified that problems that affected both RMA/cleaned and LR boards in Phase I were design related.

  6. Intense generation of respirable metal nanoparticles from a low-power soldering unit

    Energy Technology Data Exchange (ETDEWEB)

    Gómez, Virginia [Department of Chemical Engineering, Nanoscience Institute of Aragon (INA), 50018 Zaragoza (Spain); Irusta, Silvia [Department of Chemical Engineering, Nanoscience Institute of Aragon (INA), 50018 Zaragoza (Spain); Networking Biomedical Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 50018 Zaragoza (Spain); Balas, Francisco [Networking Biomedical Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 50018 Zaragoza (Spain); Instituto de Carboquímica – Consejo Superior de Investigaciones Científicas (ICB-CSIC), 50018 Zaragoza (Spain); Santamaria, Jesus, E-mail: Jesus.Santamaria@unizar.es [Department of Chemical Engineering, Nanoscience Institute of Aragon (INA), 50018 Zaragoza (Spain); Networking Biomedical Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 50018 Zaragoza (Spain)

    2013-07-15

    Highlights: • Intense generation of nanoparticles in the breathing range from a flux-soldering unit is detected. • Coagulation in the aerosol phase leads to 200-nm respirable nanoparticles up to 30 min after operation. • Nanoparticle concentration in the working environment depends on the presence of ambient air. • Metal-containing nanoparticles are collected in TEM grids and filters in the hundreds of nanometer range. -- Abstract: Evidence of intense nanoparticle generation from a low power (45 W) flux soldering unit is presented. This is a familiar device often used in daily life, including home repairs and school electronic laboratories. We demonstrate that metal-containing nanoparticles may reach high concentrations (ca. 10{sup 6} particles/cm{sup 3}) within the breathing range of the operator, with initial size distributions centered at 35–60 nm The morphological and chemical analysis of nanoparticle agglomerates collected on TEM grids and filters confirms their multiparticle structure and the presence of metals.

  7. Intense generation of respirable metal nanoparticles from a low-power soldering unit

    International Nuclear Information System (INIS)

    Gómez, Virginia; Irusta, Silvia; Balas, Francisco; Santamaria, Jesus

    2013-01-01

    Highlights: • Intense generation of nanoparticles in the breathing range from a flux-soldering unit is detected. • Coagulation in the aerosol phase leads to 200-nm respirable nanoparticles up to 30 min after operation. • Nanoparticle concentration in the working environment depends on the presence of ambient air. • Metal-containing nanoparticles are collected in TEM grids and filters in the hundreds of nanometer range. -- Abstract: Evidence of intense nanoparticle generation from a low power (45 W) flux soldering unit is presented. This is a familiar device often used in daily life, including home repairs and school electronic laboratories. We demonstrate that metal-containing nanoparticles may reach high concentrations (ca. 10 6 particles/cm 3 ) within the breathing range of the operator, with initial size distributions centered at 35–60 nm The morphological and chemical analysis of nanoparticle agglomerates collected on TEM grids and filters confirms their multiparticle structure and the presence of metals

  8. Effects of In and Ni Addition on Microstructure of Sn-58Bi Solder Joint

    Science.gov (United States)

    Mokhtari, Omid; Nishikawa, Hiroshi

    2014-11-01

    In this study, the effect of adding 0.5 wt.% and 1 wt.% In and Ni to Sn-58Bi solder on intermetallic compound (IMC) layers at the interface and the microstructure of the solder alloys were investigated during reflow and thermal aging by scanning electron microscopy and electron probe micro-analysis. The results showed that the addition of minor elements was not effective in suppressing the IMC growth during the reflow; however, the addition of 0.5 wt.% In and Ni was effective in suppressing the IMC layer growth during thermal aging. The thickening kinetics of the total IMC layer was analyzed by plotting the mean thickness versus the aging time on log-log coordinates, and the results showed the transition point from grain boundary diffusion control to a volume diffusion control mechanism. The results also showed that the minor addition of In can significantly suppress the coarsening of the Bi phase.

  9. Chips with everything

    CERN Document Server

    CERN. Geneva

    2007-01-01

    In March 1972, Sir Robin Saxby gave a talk to the Royal Television Society called 'TV and Chips' about a 'state of the art' integrated circuit, containing 50 resistors and 50 transistors. Today's 'state of the art' chips contain up to a billion transistors. This enormous leap forward illustrates how dramatically the semiconductor industry has evolved in the past 34 years. The next 10 years are predicted to bring times of turbulent change for the industry, as more and more digital devices are used around the world. In this talk, Sir Robin will discuss the history of the Microchip Industry in parallel with ARM's history, demonstrating how a small European start-up can become a world player in the IT sector. He will also present his vision of important applications and developments in the next 20 years that are likely to become even more pervasive than the mobile phone is today, and will provide anecdotes and learning points from his own experience at ARM. About ARM: Sir Robin and a group of designers from Acorn...

  10. Explosion bonding of dissimilar materials for fabricating APS front end components: Analysis of metallurgical and mechanical properties and UHV applications

    International Nuclear Information System (INIS)

    Li, Yuheng; Shu, Deming; Kuzay, T.M.

    1994-01-01

    The front end beamline section contains photon shutters and fixed masks. These components are made of OFHC copper and GlidCOP AL-15. Stainless steels (304 or 316) are also used for connecting photon shutters and fixed masks to other components that operate in the ultrahigh vacuum system. All these dissimilar materials need to be joined together. However, bonding these dissimilar materials is very difficult because of their different mechanical and thermal properties and incompatible metallurgical properties. Explosion bonding is a bonding method in which the controlled energy of a detonating explosive is used to create a metallurgical bond between two or more similar or dissimilar materials. No intermediate filler metal, for example, a brazing compound or soldering alloy, is needed to promote bonding, and no external heat need be applied. A study of the metallurgical and mechanical properties and YGV applications of GlidCop AL-15, OFHC copper, and 304 stainless steel explosion-bonded joints has been done. This report contains five parts: an ultrasonic examination of explosion-bonded joints and a standard setup; mechanical-property and thermal-cycle tests of GlidCop AL-15/304 stainless steel explosion-bonded joints; leak tests of a GlidCop AL-15/304 stainless steel explosion-bonded interfaces for UHV application; metallurgical examination of explosion-bonded interfaces and failure analysis, and discussion and conclusion

  11. Finite Element-Assisted Assessment of the Thermo-cyclic Characteristics of Leads Soldered with SnAgCu(+Bi,In) Alloys

    Science.gov (United States)

    Lis, Adrian; Nakanishi, Kohei; Matsuda, Tomoki; Sano, Tomokazu; Minagawa, Madoka; Okamoto, Masahide; Hirose, Akio

    2017-07-01

    Solder joints between leads and printed circuit boards in thin small outline packages were produced with conventional Sn1.0Ag0.7Cu (SAC107) and Sn3.0Ag0.7Cu (SAC305) solders as well as various solder alloys with gradually increasing amounts of Bi (up to 3.0 wt.%) and In (up to 1.0 wt.%) within the SAC107 base solder. The reliability of soldered leads in temperature cycle (TC) tests improved most with solder alloys containing both Bi (1.6 wt.%) and In (0.5 wt.%). Microindentation and electron probe microanalysis mappings revealed that the effect originates from a combination of solution and precipitation strengthening of the initial SAC alloy. The distribution of inelastic strain accumulation (ISA), as a measure for degradation, was determined in the solder joints by finite element calculations. It was shown that defects in the solder proximal to the lead (60-75 μm), which was underpinned by similar cracking characteristics along the lead-solder interface. The ISA was confirmed to be lower in SAC+Bi/In alloys owing to their enhanced elasto-plastic properties. Moreover, the addition of a thin Cu coating on the leads could improve the joint reliability, as suggested by the calculation of the ISA and the acceleration factor.

  12. Thermal stress in a bi-material assembly with a 'piecewise-continuous' bonding layer: theorem of three axial forces

    International Nuclear Information System (INIS)

    Suhir, E

    2009-01-01

    interfacial stresses). The maximum interfacial shearing stress in the assembly with the inhomogeneous bonding layer turned out to be only about 30% of the maximum shearing stress in an assembly with a homogeneous bonding layer having throughout its length the same modulus as the bonding material in the mid-portion of an assembly with an inhomogeneous bond. We would like to emphasize that the inhomogeneous bonding material addressed in this analysis does not necessarily have to be an epoxy one. Many other bonding materials with different moduli in the mid-portion and at the peripheral portions of the assembly could be considered for various practical applications. For instance, a high-modulus solder material such as, say, a tin-silver-copper (SAC) solder can be employed in the mid-portion of an assembly and a low-modulus solder (e.g. an indium-based alloy) at its peripheral portions. In other applications a high-modulus solder material could be considered for the mid-portion of the assembly and a low-modulus epoxy adhesive at its peripheral portions. We would also like to point out that the developed concept can be easily generalized for the situations when the bonding material is not a continuous one, but is of the ball-grid-array (BGA) or a pad-grid-array (PGA) type. Our concept could also be easily generalized for a two-dimensional case, for the situation when bending deformations should be accounted for, for non-uniform distribution of temperature (i.e. for assemblies with temperature gradients in the through-thickness and/or in the longitudinal direction), for situations when time-dependent effects (visco-elasticity, creep, stress relaxation) in the bonding material are important and for numerous other more complicated and practically important situations that might be encountered in engineering practice.

  13. Crystal plasticity finite element analysis of deformation behaviour in SAC305 solder joint

    Science.gov (United States)

    Darbandi, Payam

    Due to the awareness of the potential health hazards associated with the toxicity of lead (Pb), actions have been taken to eliminate or reduce the use of Pb in consumer products. Among those, tin (Sn) solders have been used for the assembly of electronic systems. Anisotropy is of significant importance in all structural metals, but this characteristic is unusually strong in Sn, making Sn based solder joints one of the best examples of the influence of anisotropy. The effect of anisotropy arising from the crystal structure of tin and large grain microstructure on the microstructure and the evolution of constitutive responses of microscale SAC305 solder joints is investigated. Insights into the effects of key microstructural features and dominant plastic deformation mechanisms influencing the measured relative activity of slip systems in SAC305 are obtained from a combination of optical microscopy, orientation imaging microscopy (OIM), slip plane trace analysis and crystal plasticity finite element (CPFE) modeling. Package level SAC305 specimens were subjected to shear deformation in sequential steps and characterized using optical microscopy and OIM to identify the activity of slip systems. X-ray micro Laue diffraction and high energy monochromatic X-ray beam were employed to characterize the joint scale tensile samples to provide necessary information to be able to compare and validate the CPFE model. A CPFE model was developed that can account for relative ease of activating slip systems in SAC305 solder based upon the statistical estimation based on correlation between the critical resolved shear stress and the probability of activating various slip systems. The results from simulations show that the CPFE model developed using the statistical analysis of activity of slip system not only can satisfy the requirements associated with kinematic of plastic deformation in crystal coordinate systems (activity of slip systems) and global coordinate system (shape changes

  14. Current redistribution in cables made of insulated, soldered, or oxidized strands

    International Nuclear Information System (INIS)

    Turck, B.

    1979-07-01

    Current redistributions are compared in cables made of insulated strands, soldered, or oxidized strands and insulated strands with periodic joints. After discussing the different current redistributions in the cases of a rapidly changing current and a dc current, several particular situations are investigated: what happens if a strand is broken, or if a local normal zone appears that does not affect all the strands equally, the detection of this normal zone, and the influence of short circuits between strands

  15. Life cycle assessment (LCA of lead-free solders from the environmental protection aspect

    Directory of Open Access Journals (Sweden)

    Mitovski Aleksandra M.

    2009-01-01

    Full Text Available Life-cycle assessment (LCA presents a relatively new approach, which allows comprehensive environmental consequences analysis of a product system over its entire life. This analysis is increasingly being used in the industry, as a tool for investigation of the influence of the product system on the environment, and serves as a protection and prevention tool in ecological management. This method is used to predict possible influences of a certain material to the environment through different development stages of the material. In LCA, the product systems are evaluated on a functionally equivalent basis, which, in this case, was 1000 cubic centimeters of an alloy. Two of the LCA phases, life-cycle inventory (LCA and life-cycle impact assessment (LCIA, are needed to calculate the environmental impacts. Methodology of LCIA applied in this analysis aligns every input and output influence into 16 different categories, divided in two subcategories. The life-cycle assessment reaserch review of the leadfree solders Sn-Cu, SAC (Sn-Ag-Cu, BSA (Bi-Sb-Ag and SABC (Sn-Ag-Bi-Cu respectively, is given in this paper, from the environmental protection aspect starting from production, through application process and finally, reclamation at the end-of-life, i.e. recycling. There are several opportunities for reducing the overall environmental and human health impacts of solder used in electronics manufacturing based on the results of the LCA, such as: using secondary metals reclaimed through post-industrial recycling; power consumption reducing by replacing older, less efficient reflow assembly equipment, or by optimizing the current equipment to perform at the elevated temperatures required for lead-free soldering, etc. The LCA analysis was done comparatively in relation to widely used Sn-Pb solder material. Additionally, the impact factors of material consumption, energy use, water and air reserves, human health and ecotoxicity have been ALSO considered including

  16. Evaluation on Dorsey Method in Surface Tension Measurement of Solder Liquids Containing Surfactants

    Science.gov (United States)

    Zhao, Xingke; Xie, Feiming; Fan, Jinsheng; Liu, Dayong; Huang, Jihua; Chen, Shuhai

    2018-06-01

    With the purpose of developing a feasible approach for measuring the surface tension of solders containing surfactants, the surface tension of Sn-3Ag-0.5Cu-xP solder alloys, with various drop sizes as well as different phosphorus (P) content, was evaluated using the Dorsey method based on the sessile drop test. The results show that the accuracy of the surface tension calculations depends on both of sessile drop size and the liquid metal composition. With a proper drop size, in the range of 4.5 mm to 5.3 mm in equivalent spherical diameters, the deviation of the surface tension calculation can be limited to 1.43 mN·m-1 and 6.30 mN·m-1 for SnAgCu and SnAgCu-P, respectively. The surface tension of SnAgCu-xP solder alloys decreases quickly to a minimum value when the P content reaches 0.5 wt% and subsequently increases slowly with the P content further increasing. The formation of a P-enriched surface layer and Sn4P3 intermetallic phases is regarded to be responsible for the decreasing and subsequent increasing of surface tension, respectively.

  17. Liver repair and hemorrhage control by using laser soldering of liquid albumin in a porcine model.

    Science.gov (United States)

    Wadia, Y; Xie, H; Kajitani, M

    2000-01-01

    We evaluated laser soldering by using liquid albumin for welding liver injuries. Major liver trauma has a high mortality because of immediate exsanguination and a delayed morbidity from septicemia, peritonitis, biliary fistulae, and delayed secondary hemorrhage. Eight laceration (6 x 2 cm) and eight nonanatomic resection injuries (raw surface, 6 x 2 cm) were repaired. An 805-nm laser was used to weld 50% liquid albumin-indocyanine green solder to the liver surface, reinforcing it with a free autologous omental scaffold. The animals were heparinized and hepatic inflow occlusion was used for vascular control. All 16 soldering repairs were evaluated at 3 hours. All 16 laser mediated liver repairs had minimal blood loss as compared with the suture controls. No dehiscence, hemorrhage, or bile leakage was seen in any of the laser repairs after 3 hours. Laser fusion repair of the liver is a reliable technique to gain hemostasis on the raw surface as well as weld lacerations. Copyright 2000 Wiley-Liss, Inc.

  18. Multi-layer SiC ceramics/Mo joints brazed using high-temperature solders

    International Nuclear Information System (INIS)

    Olesinska, W.; Kesik, J.

    2003-01-01

    The paper presents the results of studies on joining SiC ceramics with molybdenum, with the ceramic surface being activated by titanium, chromium or copper. Titanium or chromium were deposited by the sputtering technique, and copper - by the electro-chemical method. The microstructures of the SiC/Mo joints brazed with the CuMn13Ni3 solder and copper in a nitrogen atmosphere were examined and the results discussed. The joints, in which the ceramic surface was activated in addition with chromium, do not contain mechanical defects caused by the joining process, and the ceramic surface is covered with a continuous layer of the solder. A phase analysis of the interface surface identified an MeSiC phase. The mechanical strength of the joints in which the ceramic surface was modified by the Ti, Cr and Cu layers was markedly greater than that of the joints brazed directly to the uncoated ceramics with the use of active solders. (author)

  19. Reinforcement of high-risk anastomoses using laser-activated protein solders: a clinical study

    Science.gov (United States)

    Libutti, Steven K.; Bessler, Marc; Chabot, J.; Bass, Lawrence S.; Oz, Mehmet C.; Auteri, Joseph S.; Kirsch, Andrew J.; Nowygrod, Roman; Treat, Michael R.

    1993-07-01

    Anastomotic leakage or breakdown can result in catastrophic complications and significantly increased post-operative morbidity and mortality. Certain anastomoses are subject to a higher incidence of disruption and are therefore termed high risk. In an attempt to decrease the risk of anastomotic leaks, we reinforced sutured anastomoses with a laser activated protein solder in patients undergoing esophagojejunostomies (n equals 2), lung transplantation (n equals 2), and pancreaticojejunostomies (Whipple procedure, n equals 5). The protein solder was composed of 1.0 ml of a 25% human albumin solution, 1.0 ml of sodium hyaluronate, and 0.1 ml of Cardiogreen dye. This composition was applied to the sutured anastomosis and activated with an 860 nm pulsed diode laser. Drains were placed when appropriate and patients were followed for up to 10 months post-operatively and assessed for clinical signs of anastomotic leaks. Results to data demonstrated that there were no immediate complications as a result of the procedure. Operative time was not significantly lengthened. There were no cases of clinically significant leakage from any of the reinforced anastomoses. Laser activated protein solders may help to reduce the incidence of leakage in high risk anastomoses. Large numbers of patients and longer follow-up is needed however, to draw significant conclusions.

  20. Liver repair and hemorrhage control using laser soldering of liquid albumin in a porcine model

    Science.gov (United States)

    Wadia, Yasmin; Xie, Hua; Kajitani, Michio; Gregory, Kenton W.; Prahl, Scott A.

    2000-05-01

    The purpose of this study was to evaluate laser soldering using liquid albumin for welding liver lacerations and sealing raw surfaces created by segmental resection of a lobe. Major liver trauma has a high mortality due to immediate exsanguination and a delayed morbidity and mortality from septicemia, peritonitis, biliary fistulae and delayed secondary hemorrhage. Eight laceration injuries (6 cm long X 2 cm deep) and eight non-anatomical resection injuries (raw surface 6 cm X 2 cm) were repaired. An 805 nm laser was used to weld 53% liquid albumin-ICG solder to the liver surface, reinforcing it with a free autologous omental scaffold. The animals were heparinized to simulate coagulation failure and hepatic inflow occlusion was used for vascular control. For both laceration and resection injuries, eight soldering repairs each were evaluated at three hours. A single suture repair of each type was evaluated at three hours. All 16 laser mediated liver repairs were accompanied by minimal blood loss as compared to the suture controls. No dehiscence, hemorrhage or bile leakage was seen in any of the laser repairs after three hours. In conclusion laser fusion repair of the liver is a quick and reliable technique to gain hemostasis on the cut surface as well as weld lacerations.

  1. Dissolution and uptake of cadmium from dental gold solder alloy implants

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, B; Bergman, M; Soeremark, R [Umeaa Univ. (Sweden); Karolinska Institutet, Stockholm (Sweden))

    1977-01-01

    Pure metallic cadmium was irradiated by means of thermal neutrons. The irradiated cadmium (/sup 115/Cd) was placed in bags of gold foil and the bags were implanted subcutaneously in the neck region of mice. Two and 3 d respectively after implantation the mice were killed, the bags removed and the animals subjected to whole-body autoradiography. The autoradiograms revealed an uptake of /sup 115/Cd in liver and kidney. In another experiment specimens of a cadmium-containing dental gold solder alloy, a cadmium-free dental casting gold alloy and soldered assemblies made of these two alloys were implanted subcutaneously in the neck region of mice. The animals were killed after 6 months; cadmium analysis showed significant increases in the cadmium concentration in liver and kidney of those mice which had been given implants of gold solder alloy. The study clearly shows that due to electrochemical corrosion cadmium can be released from implants and accumulated in the kidneys and the liver.

  2. Effect of oxalic acid pretreatment of wood chips on manufacturing medium-density fiberboard

    Science.gov (United States)

    Xianjun Li; Zhiyong Cai; Eric Horn; Jerrold E. Winandy

    2011-01-01

    The main objective of this study was to evaluate the effect of oxalic acid (OA) wood chips pretreatment prior to refining, which is done to reduce energy used during the refining process. Selected mechanical and physical performances of medium-density fiberboard (MDF) – internal bonding (IB), modulus of elasticity (MOE), modulus of rupture (MOR), water absorption (WA)...

  3. Edge chipping and flexural resistance of monolithic ceramics☆

    Science.gov (United States)

    Zhang, Yu; Lee, James J.-W.; Srikanth, Ramanathan; Lawn, Brian R.

    2014-01-01

    Objective Test the hypothesis that monolithic ceramics can be developed with combined esthetics and superior fracture resistance to circumvent processing and performance drawbacks of traditional all-ceramic crowns and fixed-dental-prostheses consisting of a hard and strong core with an esthetic porcelain veneer. Specifically, to demonstrate that monolithic prostheses can be produced with a much reduced susceptibility to fracture. Methods Protocols were applied for quantifying resistance to chipping as well as resistance to flexural failure in two classes of dental ceramic, microstructurally-modified zirconias and lithium disilicate glass–ceramics. A sharp indenter was used to induce chips near the edges of flat-layer specimens, and the results compared with predictions from a critical load equation. The critical loads required to produce cementation surface failure in monolithic specimens bonded to dentin were computed from established flexural strength relations and the predictions validated with experimental data. Results Monolithic zirconias have superior chipping and flexural fracture resistance relative to their veneered counterparts. While they have superior esthetics, glass–ceramics exhibit lower strength but higher chip fracture resistance relative to porcelain-veneered zirconias. Significance The study suggests a promising future for new and improved monolithic ceramic restorations, with combined durability and acceptable esthetics. PMID:24139756

  4. Pelly Crossing wood chip boiler

    Energy Technology Data Exchange (ETDEWEB)

    1985-03-11

    The Pelly wood chip project has demonstrated that wood chips are a successful fuel for space and domestic water heating in a northern climate. Pelly Crossing was chosen as a demonstration site for the following reasons: its extreme temperatures, an abundant local supply of resource material, the high cost of fuel oil heating and a lack of local employment. The major obstacle to the smooth operation of the boiler system was the poor quality of the chip supply. The production of poor quality chips has been caused by inadequate operation and maintenance of the chipper. Dull knives and faulty anvil adjustments produced chips and splinters far in excess of the one centimetre size specified for the system's design. Unanticipated complications have caused costs of the system to be higher than expected by approximately $15,000. The actual cost of the project was approximately $165,000. The first year of the system's operation was expected to accrue $11,600 in heating cost savings. This estimate was impossible to confirm given the system's irregular operation and incremental costs. Consistent operation of the system for a period of at least one year plus the installation of monitoring devices will allow the cost effectiveness to be calculated. The wood chip system's impact on the environment was estimated to be minimal. Wood chip burning was considered cleaner and safer than cordwood burning. 9 refs., 6 figs., 6 tabs.

  5. Bonding with Your Baby

    Science.gov (United States)

    ... the future bonding of the child and parent. Adoptive parents may be concerned about bonding with their ... general emotional support. And it's OK to ask family members and friends for help in the days — ...

  6. Single chip camera active pixel sensor

    Science.gov (United States)

    Shaw, Timothy (Inventor); Pain, Bedabrata (Inventor); Olson, Brita (Inventor); Nixon, Robert H. (Inventor); Fossum, Eric R. (Inventor); Panicacci, Roger A. (Inventor); Mansoorian, Barmak (Inventor)

    2003-01-01

    A totally digital single chip camera includes communications to operate most of its structure in serial communication mode. The digital single chip camera include a D/A converter for converting an input digital word into an analog reference signal. The chip includes all of the necessary circuitry for operating the chip using a single pin.

  7. Ultra-thin chip technology and applications

    CERN Document Server

    2010-01-01

    Ultra-thin chips are the "smart skin" of a conventional silicon chip. This book shows how very thin and flexible chips can be fabricated and used in many new applications in microelectronics, microsystems, biomedical and other fields. It provides a comprehensive reference to the fabrication technology, post processing, characterization and the applications of ultra-thin chips.

  8. Interfacial microstructures and solder joint strengths of the Sn-8Zn-3Bi and Sn-9Zn-lAl Pb-free solder pastes on OSP finished printed circuit boards

    Energy Technology Data Exchange (ETDEWEB)

    Lin, C.-T. [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miaoli 36003, Taiwan (China); Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, 195 Section 4, Chung-Hsing Road, Chutung, Hsinchu 31040, Taiwan (China); Hsi, C.-S. [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miaoli 36003, Taiwan (China); Wang, M.-C. [Faculty of Fragrance and Cosmetics, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China)], E-mail: mcwang@kmu.edu.tw; Chang, T.-C.; Liang, M.-K. [Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, 195 Section 4, Chung-Hsing Road, Chutung, Hsinchu 31040, Taiwan (China)

    2008-07-14

    Two kinds of lead-free solders, Sn-8Zn-3Bi and Sn-9Zn-lAl, were used to mount passive components onto printed circuit boards via a re-flow soldering process. The samples were stored at 150 deg. C for 200, 400, 600, 800, and 1100 h. The microstructures of the samples after aged at 150 deg. C for various times were characterized using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and the analyzed of solder joint shear strengths. The joint strength between Sn-8Zn-3Bi and Cu pad was about 4.0 {+-} 0.3 kg, while the strength between Sn-9Zn-lAl and Cu pad had values of 2.6 {+-} 0.1 kg. Both kinds of solder joints exhibited reduced strengths with increasing aging times. After aging at 150 deg. C for 1100 h, the joints strengths of Sn-8Zn-3Bi and Sn-9Zn-lAl were 1.8 {+-} 0.3 and 1.7 {+-} 0.3 kg, respectively. Both the Sn-8Zn-3Bi and Sn-9Zn-lAl joints showed brittle fracture behaviors. A flat layer of Cu{sub 5}Zn{sub 8} intermetallic compound (IMC) was formed between Sn-8Zn-3Bi solder and Cu pad after reflow. When the aging time was increased to 400 h, Zn-depletion and formation of Cu{sub 6}Sn{sub 5} IMC were observed in the solders due to the interaction between the tin and zinc compounds. The interaction between Sn-9Zn-lAl solder and Cu pad had similar behavior, however, Cu{sub 6}Sn{sub 5} IMC formed in Sn-9Zn-lAl solder when after aging at 150 deg. C for 600 h. As the aging time increased, both types of solders generated clear IMC spalling layers with large and continuous voids. Those voids substantially decreased the joint strength.

  9. Australia's Bond Home Bias

    OpenAIRE

    Anil V. Mishra; Umaru B. Conteh

    2014-01-01

    This paper constructs the float adjusted measure of home bias and explores the determinants of bond home bias by employing the International Monetary Fund's high quality dataset (2001 to 2009) on cross-border bond investment. The paper finds that Australian investors' prefer investing in countries with higher economic development and more developed bond markets. Exchange rate volatility appears to be an impediment for cross-border bond investment. Investors prefer investing in countries with ...

  10. Phenylacetylene and H bond

    Indian Academy of Sciences (India)

    ... all resembling H bonds. Non-linear H bonds due to secondary interactions. C-H stretching frequency shows blue shift. Heavy atom distances are longer than the sum of van der Waals radii. Formed a task group through IUPAC to come up with a modern definition of H bond. 15 international experts including Desiraju.

  11. In search of low cost biological analysis: Wax or acrylic glue bonded paper microfluidic devices

    KAUST Repository

    Kodzius, Rimantas

    2011-01-22

    In this body of work we have been developing and characterizing paper based microfluidic fabrication technologies to produce low cost biological analysis. Specifically we investigated the performance of paper microfluidics that had been bonded using wax or acrylic glue, and characterized the affect of these and other microfluidic materials on the polymerase chain reaction (PCR). We report a simple, low-cost and detachable microfluidic chip incorporating easily accessible paper, glass slides or other polymer films as the chip materials along with adhesive wax or cyanoacrylate-based resin as the recycling bonding material. We use a laser to cut through the paper or film to form patterns and then sandwich the paper and film between glass sheets or polymer membranes. The hot-melt adhesive wax or simple cyanoacrylate-based resin can realize bridge bonding between various materials, for example, paper, polymethylmethacrylate film, glass sheets, or metal plate. The wax bonding process is reversible and the wax is reusable through a melting and cooling process. With this process, a three-dimensional (3D) microfluidic chip is achievable by evacuating the channels of adhesive material in a hot-water. We applied the wax-paper based microfluidic chip to HeLa cell electroporation. Subsequently, a prototype of a 5-layer 3D chip was fabricated by multilayer wax bonding. To check the sealing ability and the durability of the chip, green fluorescence protein recombinant E. coli bacteria were cultured, with which the chemotaxis of E. coli was studied in order to determine the influence of antibiotic ciprofloxacin concentration on the E. coli migration. The chip bonded with cyanoacrylate-based resin was tested by measuring protein concentration and carrying out DNA capillary electrophoresis. To study the biocompatibility and applicability of our microfluidic chip fabrication technology, we tested the PCR compatibility of our chip materials along with various other common materials

  12. Chemical bond fundamental aspects of chemical bonding

    CERN Document Server

    Frenking, Gernot

    2014-01-01

    This is the perfect complement to ""Chemical Bonding - Across the Periodic Table"" by the same editors, who are two of the top scientists working on this topic, each with extensive experience and important connections within the community. The resulting book is a unique overview of the different approaches used for describing a chemical bond, including molecular-orbital based, valence-bond based, ELF, AIM and density-functional based methods. It takes into account the many developments that have taken place in the field over the past few decades due to the rapid advances in quantum chemica

  13. Wafer Scale Integration of CMOS Chips for Biomedical Applications via Self-Aligned Masking.

    Science.gov (United States)

    Uddin, Ashfaque; Milaninia, Kaveh; Chen, Chin-Hsuan; Theogarajan, Luke

    2011-12-01

    This paper presents a novel technique for the integration of small CMOS chips into a large area substrate. A key component of the technique is the CMOS chip based self-aligned masking. This allows for the fabrication of sockets in wafers that are at most 5 µm larger than the chip on each side. The chip and the large area substrate are bonded onto a carrier such that the top surfaces of the two components are flush. The unique features of this technique enable the integration of macroscale components, such as leads and microfluidics. Furthermore, the integration process allows for MEMS micromachining after CMOS die-wafer integration. To demonstrate the capabilities of the proposed technology, a low-power integrated potentiostat chip for biosensing implemented in the AMI 0.5 µm CMOS technology is integrated in a silicon substrate. The horizontal gap and the vertical displacement between the chip and the large area substrate measured after the integration were 4 µm and 0.5 µm, respectively. A number of 104 interconnects are patterned with high-precision alignment. Electrical measurements have shown that the functionality of the chip is not affected by the integration process.

  14. Robust design and thermal fatigue life prediction of anisotropic conductive film flip chip package

    International Nuclear Information System (INIS)

    Nam, Hyun Wook

    2004-01-01

    The use of flip-chip technology has many advantages over other approaches for high-density electronic packaging. ACF(Anisotropic Conductive Film) is one of the major flip-chip technologies, which has short chip-to-chip interconnection length, high productivity, and miniaturization of package. In this study, thermal fatigue life of ACF bonding flip-chip package has been predicted. Elastic and thermal properties of ACF were measured by using DMA and TMA. Temperature dependent nonlinear bi-thermal analysis was conducted and the result was compared with Moire interferometer experiment. Calculated displacement field was well matched with experimental result. Thermal fatigue analysis was also conducted. The maximum shear strain occurs at the outmost located bump. Shear stress-strain curve was obtained to calculate fatigue life. Fatigue model for electronic adhesives was used to predict thermal fatigue life of ACF bonding flip-chip packaging. DOE (Design Of Experiment) technique was used to find important design factors. The results show that PCB CTE (Coefficient of Thermal Expansion) and elastic modulus of ACF material are important material parameters. And as important design parameters, chip width, bump pitch and bump width were chose. 2 nd DOE was conducted to obtain RSM equation for the choose 3 design parameter. The coefficient of determination (R 2 ) for the calculated RSM equation is 0.99934. Optimum design is conducted using the RSM equation. MMFD (Modified Method for Feasible Direction) algorithm is used to optimum design. The optimum value for chip width, bump pitch and bump width were 7.87mm, 430μm, and 78μm, respectively. Approximately, 1400 cycles have been expected under optimum conditions. Reliability analysis was conducted to find out guideline for control range of design parameter. Sigma value was calculated with changing standard deviation of design variable. To acquire 6 sigma level thermal fatigue reliability, the Std. Deviation of design parameter

  15. The effect of micro alloying on the microstructure evolution of Sn-Ag-Cu lead-free solder

    Science.gov (United States)

    Werden, Jesse

    The microelectronics industry is required to obtain alternative Pb-free soldering materials due to legal, environmental, and technological factors. As a joining material, solder provides an electrical and mechanical support in electronic assemblies and therefore, the properties of the solder are crucial to the durability and reliability of the solder joint and the function of the electronic device. One major concern with new Pb-free alternatives is that the microstructure is prone to microstructural coarsening over time which leads to inconsistent properties over the device's lifetime. Power aging the solder is a common method of stabilizing the microstructure for Pb-based alloys, however, it is unclear if this will be an appropriate solution to the microstructural coarsening of Pb-free solders. The goal of this work is to develop a better understanding of the coarsening process in new solder alloys and to suggest methods of stabilizing the solder microstructure. Microalloying is one potential solution to the microstructural coarsening problem. This experiment consists of a microstructural coarsening study of SAC305 in which each sample has been alloyed with one of three different solutes, directionally solidified at 100microm/s, and then aged at three different temperatures over a total period of 20 days. There are several important conclusions from this experiment. First, the coarsening kinetics of the intermetallics in the ternary eutectic follow the Ostwald ripening model where r3 in proprotional to t for each alloying constituent. Second, the activation energy for coarsening was found to be 68.1+/-10.3 kJ/mol for the SAC305 samples, Zn had the most significant increase in the activation energy increasing it to 88.8+/-34.9 kJ/mol for the SAC+Zn samples, Mn also increased the activation energy to 83.2+/-20.8 kJ/mol for the SAC+Mn samples, and Sb decreased the activation energy to 48.0+/-3.59 kJ/mol for the SAC+Sb samples. Finally, it was found that the

  16. A prototype pixel readout chip for asynchronous detection applications

    International Nuclear Information System (INIS)

    Raymond, D.M.; Hall, G.; Lewis, A.J.; Sharp, P.H.

    1991-01-01

    A two-dimensional array of amplifier cells has been fabricated as a prototype readout system for a matching array of silicon diode detectors. Each cell contains a preamplifier, shaping amplifier, comparator and analogue signal storage in an area of 300 μmx320 μm using 3 μm CMOS technology. Full size chips will be bump bonded to pixel detector arrays. Low noise and asynchronous operation are novel design features. With noise levels of less than 250 rms electrons for input capacitances up to 600 fF, pixel detectors will be suitable for autoradiography, synchrotron X-ray and high energy particle detection applications. The design of the prototype chip is presented and future developments and prospects for applications are discussed. (orig.)

  17. TID-dependent current measurements of IBL readout chips

    Energy Technology Data Exchange (ETDEWEB)

    Dette, Karola [TU Dortmund, Experimentelle Physik IV (Germany); CERN (Switzerland); Collaboration: ATLAS Pixel-Collaboration

    2016-07-01

    The ATLAS detector consists of several subsystems with a hybrid pixel detector as the innermost component of the tracking system. The pixel detector has been composed of three layers of silicon sensor assemblies during the first data taking run of the LHC and has been upgraded with a new 4th layer, the so-called Insertable B-Layer (IBL), in summer 2014. Each silicon sensor of the IBL is connected to a Front End readout chip (FE-I4) via bump bonds. During the first year of data taking an increase of the LV current produced by the readout chips was observed. This increase could be traced back to radiation damage inside the silicon. The dependence of the current on the Total Ionizing Dose (TID) and temperature has been tested with X-ray irradiations and will be presented in this talk.

  18. Interfacial Reaction and IMC Growth of an Ultrasonically Soldered Cu/SAC305/Cu Structure during Isothermal Aging

    Directory of Open Access Journals (Sweden)

    Yulong Li

    2018-01-01

    Full Text Available In order to accelerate the growth of interfacial intermetallic compound (IMC layers in a soldering structure, Cu/SAC305/Cu was first ultrasonically spot soldered and then subjected to isothermal aging. Relatively short vibration times, i.e., 400 ms and 800 ms, were used for the ultrasonic soldering. The isothermal aging was conducted at 150 °C for 0, 120, 240, and 360 h. The evolution of microstructure, the IMC layer growth mechanism during aging, and the shear strength of the joints after aging were systemically investigated. Results showed the following. (i Formation of intermetallic compounds was accelerated by ultrasonic cavitation and streaming effects, the thickness of the interfacial Cu6Sn5 layer increased with aging time, and a thin Cu3Sn layer was identified after aging for 360 h. (ii The growth of the interfacial IMC layer of the ultrasonically soldered Cu/SAC305/Cu joints followed a linear function of the square root of the aging time, revealing a diffusion-controlled mechanism. (iii The tensile shear strength of the joint decreased to a small extent with increasing aging time, owing to the combined effects of IMC grain coarsening and the increase of the interfacial IMC. (iv Finally, although the fracture surfaces and failure locations of the joint soldered with 400 ms and 800 ms vibration times show similar characteristics, they are influenced by the aging time.

  19. Comparative Study of ENIG and ENEPIG as Surface Finishes for a Sn-Ag-Cu Solder Joint

    Science.gov (United States)

    Yoon, Jeong-Won; Noh, Bo-In; Jung, Seung-Boo

    2011-09-01

    Interfacial reactions and joint reliability of Sn-3.0Ag-0.5Cu solder with two different surface finishes, electroless nickel-immersion gold (ENIG) and electroless nickel-electroless palladium-immersion gold (ENEPIG), were evaluated during a reflow process. We first compared the interfacial reactions of the two solder joints and also successfully revealed a connection between the interfacial reaction behavior and mechanical reliability. The Sn-Ag-Cu/ENIG joint exhibited a higher intermetallic compound (IMC) growth rate and a higher consumption rate of the Ni(P) layer than the Sn-Ag-Cu/ENEPIG joint. The presence of the Pd layer in the ENEPIG suppressed the growth of the interfacial IMC layer and the consumption of the Ni(P) layer, resulting in the superior interfacial stability of the solder joint. The shear test results show that the ENIG joint fractured along the interface, exhibiting indications of brittle failure possibly due to the brittle IMC layer. In contrast, the failure of the ENEPIG joint only went through the bulk solder, supporting the idea that the interface is mechanically reliable. The results from this study confirm that the Sn-Ag-Cu/ENEPIG solder joint is mechanically robust and, thus, the combination is a viable option for a Pb-free package system.

  20. CO2 temperature-controlled laser soldering of pig trachea incisions in vitro using flexible albumin bands

    Science.gov (United States)

    Sharvit, Dan; Vasilyev, Tamar; Vasserman, Irena; Simhon, David; Kariv, Naam; DeRowe, Ari; Katzir, Abraham

    2005-04-01

    Resection of a segment of the trachea is a procedure applied for the removal of cervical tumors invading the trachea, or for the treatment of severe tracheal stenosis. The current method of anastomosis is based on multiple sutures. The main drawbacks of this method are: 1) A long procedure time, 2) An air leakage, and 3) An inflammatory response to the sutures. In this study we evaluated the feasibility and effectiveness of the use of temperature controlled CO2 laser soldering of incisions in pig tracheas in vitro. A transverse incision was made in a separated pig trachea. A flexible albumin band was prepared and was laser soldered with albumin solder to the outer surface of the trachea, covering the incision. The soldered trachea ends were sealed and the burst pressure was measured. In a series of in vitro experiments, the mean burst pressure was found to be 230 mm Hg. These preliminary results demonstrated that laser soldering using a flexible albumin band may be a useful method for sealing an incision in the trachea.

  1. Electrical Resistance of Nb$_{3}$Sn/Cu Splices Produced by Electromagnetic Pulse Technology and Soft Soldering

    CERN Document Server

    Schoerling, D; Scheuerlein, C; Atieh, S; Schaefer, R

    2011-01-01

    The electrical interconnection of Nb$_{3}$Sn/Cu strands is a key issue for the construction of Nb$_{3}$Sn based damping ring wigglers and insertion devices for third generation light sources. We compare the electrical resistance of Nb$_{3}$Sn/Cu splices manufactured by solid state welding using Electromagnetic Pulse Technology (EMPT) with that of splices produced by soft soldering with two different solders. The resistance of splices produced by soft soldering depends strongly on the resistivity of the solder alloy at the operating temperature. By solid state welding splice resistances below 10 nOhm can be achieved with 1 cm strand overlap length only, which is about 4 times lower than the resistance of Sn96Ag4 soldered splices with the same overlap length. The comparison of experimental results with Finite Element simulations shows that the electrical resistance of EMPT welded splices is determined by the resistance of the stabilizing copper between the superconducting filaments and confirms that welding of ...

  2. Development of Sn-Ag-Cu-X Solders for Electronic Assembly by Micro-Alloying with Al

    Science.gov (United States)

    Boesenberg, Adam J.; Anderson, Iver E.; Harringa, Joel L.

    2012-07-01

    Of Pb-free solder choices, an array of solder alloys based on the Sn-Ag-Cu (SAC) ternary eutectic ( T eut = 217°C) composition have emerged with potential for broad use, including ball grid array (BGA) joints that cool slowly. This work investigated minor substitutional additions of Al (0.05Al), but the suppression effect faded for >0.20Al. Undercooling suppression did not correlate specifically with blade suppression since it became significant at 0.10Al and increased continuously with greater Al to 0.25Al. Surprisingly, an intermediate range of Al content (0.10 wt.% to 0.20 wt.% Al) promoted formation of significant populations of 2- μm to 5- μm faceted Cu-Al particles, identified as Cu33Al17, that clustered at the top of the solder joint matrix and exhibited extraordinary hardness. Clustering of Cu33Al17 was attributed to its buoyancy, from a lower density than Sn liquid, and its early position in the nucleation sequence within the solder matrix, permitting unrestricted migration to the top interface. Joint microstructures and implications for the full nucleation sequence for these SAC + Al solder joints are discussed, along with possible benefits from the clustered particles for improved thermal cycling resistance.

  3. Tunable on chip optofluidic laser

    DEFF Research Database (Denmark)

    Bakal, Avraham; Vannahme, Christoph; Kristensen, Anders

    2016-01-01

    On chip tunable laser is demonstrated by realizing a microfluidic droplet array. The periodicity is controlled by the pressure applied to two separate inlets, allowing to tune the lasing frequency over a broad spectral range.......On chip tunable laser is demonstrated by realizing a microfluidic droplet array. The periodicity is controlled by the pressure applied to two separate inlets, allowing to tune the lasing frequency over a broad spectral range....

  4. Stability of molybdenum nanoparticles in Sn-3.8Ag-0.7Cu solder during multiple reflow and their influence on interfacial intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Haseeb, A.S.M.A., E-mail: haseeb@um.edu.my; Arafat, M.M., E-mail: arafat_mahmood@yahoo.com; Johan, Mohd Rafie, E-mail: mrafiej@um.edu.my

    2012-02-15

    This work investigates the effects of molybdenum nanoparticles on the growth of interfacial intermetallic compound between Sn-3.8Ag-0.7Cu solder and copper substrate during multiple reflow. Molybdenum nanoparticles were mixed with Sn-3.8Ag-0.7Cu solder paste by manual mixing. Solder samples were reflowed on a copper substrate in a 250 Degree-Sign C reflow oven up to six times. The molybdenum content of the bulk solder was determined by inductive coupled plasma-optical emission spectrometry. It is found that upon the addition of molybdenum nanoparticles to Sn-3.8Ag-0.7Cu solder, the interfacial intermetallic compound thickness and scallop diameter decreases under all reflow conditions. Molybdenum nanoparticles do not appear to dissolve or react with the solder. They tend to adsorb preferentially at the interface between solder and the intermetallic compound scallops. It is suggested that molybdenum nanoparticles impart their influence on the interfacial intermetallic compound as discrete particles. The intact, discrete nanoparticles, by absorbing preferentially at the interface, hinder the diffusion flux of the substrate and thereby suppress the intermetallic compound growth. - Highlights: Black-Right-Pointing-Pointer Mo nanoparticles do not dissolve or react with the SAC solder during reflow. Black-Right-Pointing-Pointer Addition of Mo nanoparticles results smaller IMC thickness and scallop diameter. Black-Right-Pointing-Pointer Mo nanoparticles influence the interfacial IMC through discrete particle effect.

  5. Microstructural effects on constitutive and fatigue fracture behavior of TinSilverCopper solder

    Science.gov (United States)

    Tucker, Jonathon P.

    As microelectronic package construction becomes more diverse and complex, the need for accurate, geometry-independent material constitutive and failure models increases. Evaluations of packages based on accelerated environmental tests (such as accelerated thermal cycling or power cycling) only provide package-dependent reliability information. In addition, extrapolations of such test data to life predictions under field conditions are often empirical. Besides geometry, accelerated environmental test data must account for microstructural factors such as alloy composition or isothermal aging condition, resulting in expensive experimental variation. In this work, displacement-controlled, creep, and fatigue lap shear tests are conducted on specially designed SnAgCu test specimens with microstructures representative to those found in commercial microelectronic packages. The data are used to develop constitutive and fatigue fracture material models capable of describing deformation and fracture behavior for the relevant temperature and strain rate ranges. Furthermore, insight is provided into the microstructural variation of solder joints and the subsequent effect on material behavior. These models are appropriate for application to packages of any geometrical construction. The first focus of the thesis is on Pb-mixed SnAgCu solder alloys. During the transition from Pb-containing solders to Pb-free solders, joints composed of a mixture of SnPb and SnAgCu often result from either mixed assemblies or rework. Three alloys of 1, 5 and 20 weight percent Pb were selected so as to represent reasonable ranges of Pb contamination expected from different 63Sn37Pb components mixed with Sn3.0Ag0.5Cu. Displacement-controlled (constant strain rate) and creep tests were performed at temperatures of 25°C, 75°C, and 125°C using a double lap shear test setup that ensures a nearly homogeneous state of plastic strain at the joint interface. Rate-dependent constitutive models for Pb

  6. LED Die-Bonded on the Ag/Cu Substrate by a Sn-BiZn-Sn Bonding System

    Science.gov (United States)

    Tang, Y. K.; Hsu, Y. C.; Lin, E. J.; Hu, Y. J.; Liu, C. Y.

    2016-12-01

    In this study, light emitting diode (LED) chips were die-bonded on a Ag/Cu substrate by a Sn-BixZn-Sn bonding system. A high die-bonding strength is successfully achieved by using a Sn-BixZn-Sn ternary system. At the bonding interface, there is observed a Bi-segregation phenomenon. This Bi-segregation phenomenon solves the problems of the brittle layer-type Bi at the joint interface. Our shear test results show that the bonding interface with Bi-segregation enhances the shear strength of the LED die-bonding joints. The Bi-0.3Zn and Bi-0.5Zn die-bonding cases have the best shear strength among all die-bonding systems. In addition, we investigate the atomic depth profile of the deposited Bi-xZn layer by evaporating Bi-xZn E-gun alloy sources. The initial Zn content of the deposited Bi-Zn alloy layers are much higher than the average Zn content in the deposited Bi-Zn layers.

  7. Interface analysis of embedded chip resistor device package and its effect on drop shock reliability.

    Science.gov (United States)

    Park, Se-Hoon; Kim, Sun Kyoung; Kim, Young-Ho

    2012-04-01

    In this study, the drop reliability of an embedded passive package is investigated under JESD22-B111 condition. Chip resistors were buried in a PCB board, and it was electrically interconnected by electroless and electrolytic copper plating on a tin pad of a chip resistor without intermetallic phase. However tin, nickel, and copper formed a complex intermetallic phase, such as (Cu, Ni)6Sn5, (Cu, Ni)3Sn, and (Ni, Cu)3Sn2, at the via interface and via wall after reflow and aging. Since the amount of the tin layer was small compared with the solder joint, excessive intermetallic layer growth was not observed during thermal aging. Drop failures are always initiated at the IMC interface, and as aging time increases Cu-Sn-Ni IMC phases are transformed continuously due to Cu diffusion. We studied the intermetallic formation of the Cu via interface and simulated the stress distribution of drop shock by using material properties and board structure of embedded passive boards. The drop simulation was conducted according to the JEDEC standard. It was revealed that the crack starting point related to failure fracture changed due to intermetallic phase transformation along the via interface, and the position where failure occurs experimentally agrees well with our simulation results.

  8. A novel metal-to-metal bonding process through in-situ formation of Ag nanoparticles using Ag2O microparticles

    International Nuclear Information System (INIS)

    Hirose, Akio; Tatsumi, Hiroaki; Takeda, Naoya; Akada, Yusuke; Ogura, Tomo; Ide, Eiichi; Morita, Toshiaki

    2009-01-01

    The metal-to-metal bonding has been successfully achieved via the bonding process using Ag metallo-organic nanoparticles at a bonding temperature of around 300-, which can be alternative to the current microsoldering in electronics assembly using high-temperature solders. However, further reduction of bonding temperature and/or bonding pressure is needed. In the present research, a novel bonding process through in-situ formation of Ag nanoparticles instead of the filler material of the Ag metallo-organic nanoparticles has been developed. The Ag nanoparticles can form by the reduction of Ag 2 O particles. In this study, the Ag 2 O particles were mixed with triethylene glycol as a reducing agent to form a paste for bonding. The Au coated cylindrical specimens were bonded using the paste. The Ag nanoparticles formed at around 130 to 160 through the reduction process of Ag2O particles with triethylene glycol. The Ag nanoparticles were immediately sintered each other due to a great surface energy per volume. A transmission electron microscope observation revealed that the sintered Ag metallurgically bonded to the Au substrate at around 160 and a dense Ag layer formed after further heating. The tensile strength of the joint bonded at 250 under a bonding pressure of 5MPa was around 60MPa

  9. Evaluating print performance of Sn-Ag-Cu lead-free solder pastes used in electronics assembly process

    Science.gov (United States)

    Mallik, S.; Bauer, R.; Hübner, F.; Ekere, N. N.

    2011-01-01

    Solder paste is the most widely used interconnection material in the electronic assembly process for attaching electronic components/devices directly onto the surface of printed circuit boards, using stencil printing process. This paper evaluates the performance of three different commercially available Sn-Ag-Cu solder pastes formulated with different particle size distributions (PSD), metal content and alloy composition. A series of stencil printing tests were carried out using a specially designed stencil of 75 μm thickness and apertures of 300×300 μm2 dimension and 500 μm pitch sizes. Solder paste printing behaviors were found related to attributes such as slumping and surface tension and printing performance was correlated with metal content and PSD. The results of the study should benefit paste manufacturers and SMT assemblers to improve their products and practices.

  10. In search of low cost biological analysis: Wax or acrylic glue bonded paper microfluidic devices

    KAUST Repository

    Kodzius, Rimantas; Gong, Xiuqing; Li, Shunbo; Qin, Jianhua; Wen, Weijia; Wu, Jinbo; Xiao, Kang; Yi, Xin

    2011-01-01

    We report a simple, low-cost and detachable microfluidic chip incorporating easily accessible paper, glass slides or other polymer films as the chip materials along with adhesive wax or cyanoacrylate-based resin as the recycling bonding material. We use a laser to cut through the paper or film to form patterns and then sandwich the paper and film between glass sheets or polymer membranes. The hot-melt adhesive wax or simple cyanoacrylate-based resin can realize bridge bonding between various materials, for example, paper, polymethylmethacrylate film, glass sheets, or metal plate. The wax bonding process is reversible and the wax is reusable through a melting and cooling process. With this process, a three-dimensional (3D) microfluidic chip is achievable by evacuating the channels of adhesive material in a hot-water. We applied the wax-paper based microfluidic chip to HeLa cell electroporation. Subsequently, a prototype of a 5-layer 3D chip was fabricated by multilayer wax bonding. To check the sealing ability and the durability of the chip, green fluorescence protein recombinant E. coli bacteria were cultured, with which the chemotaxis of E. coli was studied in order to determine the influence of antibiotic ciprofloxacin concentration on the E. coli migration. The chip bonded with cyanoacrylate-based resin was tested by measuring protein concentration and carrying out DNA capillary electrophoresis. To study the biocompatibility and applicability of our microfluidic chip fabrication technology, we tested the PCR compatibility of our chip materials along with various other common materials employed in the fabrication of microfluidic chips including: silicon, several kinds of silicon oxide, glasses, plastics, wax, and adhesives, etc. Two-temperature PCR was performed with these materials to determine their PCR-inhibitory effect. In most of the cases, addition of bovine serum albumin effectively improved the reaction yield. We also studied the individual PCR components

  11. Polymer multilevel lab-on-chip systems for electrochemical sensing

    DEFF Research Database (Denmark)

    Matteucci, Marco; Larsen, Simon Tylsgaard; Garau, Alessandro

    2013-01-01

    with depths as small as tens of nanometers and as big as hundreds of microns on the same polymer chip. The authors also describe in detail the fabrication procedure of polymer substrates with embedded Au and pedot:tosylate electrodes for electrochemical applications. The electrode fabrication process...... is simple and fit for integration in a production scheme. The electrode–substrates are then bonded to injection molded counterparts to be used for electrochemical applications. A dimensional and functional characterization of the electrodes is also presented here....

  12. Numerical prediction of mechanical properties of Pb-Sn solder alloys containing antimony, bismuth and or silver ternary trace elements

    Science.gov (United States)

    Gadag, Shiva P.; Patra, Susant

    2000-12-01

    Solder joint interconnects are mechanical means of structural support for bridging the various electronic components and providing electrical contacts and a thermal path for heat dissipation. The functionality of the electronic device often relies on the structural integrity of the solder. The dimensional stability of solder joints is numerically predicted based on their mechanical properties. Algorithms to model the kinetics of dissolution and subsequent growth of intermetallic from the complete knowledge of a single history of time-temperature-reflow profile, by considering equivalent isothermal time intervals, have been developed. The information for dissolution is derived during the heating cycle of reflow and for the growth process from cooling curve of reflow profile. A simple and quick analysis tool to derive tensile stress-strain maps as a function of the reflow temperature of solder and strain rate has been developed by numerical program. The tensile properties are used in modeling thermal strain, thermal fatigue and to predict the overall fatigue life of solder joints. The numerical analysis of the tensile properties as affected by their composition and rate of testing, has been compiled in this paper. A numerical model using constitutive equation has been developed to evaluate the interfacial fatigue crack growth rate. The model can assess the effect of cooling rate, which depends on the level of strain energy release rate. Increasing cooling rate from normalizing to water-quenching, enhanced the fatigue resistance to interfacial crack growth by up to 50% at low strain energy release rate. The increased cooling rates enhanced the fatigue crack growth resistance by surface roughening at the interface of solder joint. This paper highlights salient features of process modeling. Interfacial intermetallic microstructure is affected by cooling rate and thereby affects the mechanical properties.

  13. Interconnection of thermal parameters, microstructure and mechanical properties in directionally solidified Sn–Sb lead-free solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Marcelino; Costa, Thiago [Department of Manufacturing and Materials Engineering, University of Campinas — UNICAMP, 13083-860 Campinas, SP (Brazil); Rocha, Otávio [Federal Institute of Education, Science and Technology of Pará — IFPA, 66093-020 Belém, PA (Brazil); Spinelli, José E. [Department of Materials Engineering, Federal University of São Carlos — UFSCar, 13565-905 São Carlos, SP (Brazil); Cheung, Noé, E-mail: cheung@fem.unicamp.br [Department of Manufacturing and Materials Engineering, University of Campinas — UNICAMP, 13083-860 Campinas, SP (Brazil); Garcia, Amauri [Department of Manufacturing and Materials Engineering, University of Campinas — UNICAMP, 13083-860 Campinas, SP (Brazil)

    2015-08-15

    Considerable effort is being made to develop lead-free solders for assembling in environmental-conscious electronics, due to the inherent toxicity of Pb. The search for substitute alloys of Pb–Sn solders has increased in order to comply with different soldering purposes. The solder must not only meet the expected levels of electrical performance but may also have appropriate mechanical strength, with the absence of cracks in the solder joints. The Sn–Sb alloy system has a range of compositions that can be potentially included in the class of high temperature solders. This study aims to establish interrelations of solidification thermal parameters, microstructure and mechanical properties of Sn–Sb alloys (2 wt.%Sb and 5.5 wt.%Sb) samples, which were directionally solidified under cooling rates similar to those of reflow procedures in industrial practice. A complete high-cooling rate cellular growth is shown to be associated with the Sn–2.0 wt.%Sb alloy and a reverse dendrite-to-cell transition is observed for the Sn–5.5 wt.%Sb alloy. Strength and ductility of the Sn–2.0 wt.%Sb alloy are shown not to be affected by the cellular spacing. On the other hand, a considerable variation in these properties is associated with the cellular region of the Sn–5.5 wt.%Sb alloy casting. - Graphical abstract: Display Omitted - Highlights: • The microstructure of the Sn–2 wt.%Sb alloy is characterized by high-cooling rates cells. • Reverse dendrite > cell transition occurs for Sn–5.5 wt.%Sb alloy: cells prevail for cooling rates > 1.2 K/s. • Sn–5.5 wt.%Sb alloy: the dendritic region occurs for cooling rates < 0.9 K/s. • Sn–5.5 wt.%Sb alloy: tensile properties are improved with decreasing cellular spacing.

  14. In-vitro investigations of skin closure using diode laser and protein solder containing gold nano shells

    International Nuclear Information System (INIS)

    Nourbakhsh, M. S.; Etrati Khosroshahi, M.

    2011-01-01

    Laser tissue soldering is a new technique for repair of various tissues including the skin, liver, articular cartilage and nerves and is a promising alternative to suture. To overcome the problems of thermal damage to surrounding tissues and low laser penetration depth, some exogenous chromophores such as gold nano shells, a new class of nanoparticles consisting of a dielectric core surrounded by a thin metal shell, are used. The aims of this study were to use two different concentrations of gold nano shells as the exogenous material for skin tissue soldering and also to examine the effects of laser soldering parameters on the properties of the repaired skin. Material and Methods: Two mixtures of albumin solder and different concentrations of gold nano shells were prepared. A full thickness incision of 2*20 mm 2 was made on the surface and after placing 50 μ1 of the solder mixture on the incision, an 810 nm diode laser was used to irradiate it at different power densities. The changes of tensile strength, σt, due to temperature rise, number of scan (Ns), and scan velocity (Vs) were investigated. Results: The results showed that the tensile strength of the repaired skin increased with increasing irradiance for both gold nano shell concentrations. In addition, at constant laser irradiance (I), the tensile strength of the repaired incision increased with increasing Ns and decreasing Vs. In our case, this corresponded to σt = 1610 g/cm 2 at I ∼ 60 W cm-2, T ∼ 65 d egree C , Ns = 10 and Vs = 0.2 mms-1. Discussion and Conclusion: Gold nano shells can be used as an indocyanine green dye alterative for laser tissue soldering. Although by increasing the laser power density, the tensile strength of the repaired skin increases, an optimum power density must be considered due to the resulting increase in tissue temperature.

  15. Advanced chip designs and novel cooling techniques for brightness scaling of industrial, high power diode laser bars

    Science.gov (United States)

    Heinemann, S.; McDougall, S. D.; Ryu, G.; Zhao, L.; Liu, X.; Holy, C.; Jiang, C.-L.; Modak, P.; Xiong, Y.; Vethake, T.; Strohmaier, S. G.; Schmidt, B.; Zimer, H.

    2018-02-01

    The advance of high power semiconductor diode laser technology is driven by the rapidly growing industrial laser market, with such high power solid state laser systems requiring ever more reliable diode sources with higher brightness and efficiency at lower cost. In this paper we report simulation and experimental data demonstrating most recent progress in high brightness semiconductor laser bars for industrial applications. The advancements are in three principle areas: vertical laser chip epitaxy design, lateral laser chip current injection control, and chip cooling technology. With such improvements, we demonstrate disk laser pump laser bars with output power over 250W with 60% efficiency at the operating current. Ion implantation was investigated for improved current confinement. Initial lifetime tests show excellent reliability. For direct diode applications 96% polarization are additional requirements. Double sided cooling deploying hard solder and optimized laser design enable single emitter performance also for high fill factor bars and allow further power scaling to more than 350W with 65% peak efficiency with less than 8 degrees slow axis divergence and high polarization.

  16. In situ investigation of SnAgCu solder alloy microstructure

    International Nuclear Information System (INIS)

    Pietrikova, Alena; Bednarcik, Jozef; Durisin, Juraj

    2011-01-01

    Research highlights: → In situ X-ray diffraction investigation enabled detailed analysis of the melting and solidification process of the SAC305 alloy. → It was found that the SAC305 solder melts at 230 deg. C. When cooling from 240 deg. C the SAC305 alloy solidifies at the temperature of 214 deg. C. During solidification β-Sn and Cu 6 Sn 5 is also formed. Formation of Ag 3 Sn occurs at 206 deg. C and the remaining amount of alloy crystallizes approximately at 160 deg. C. → Furthermore, observation of the thermal expansion behaviour of the β-Sn tetragonal unit cell revealed linear dependence of the unit cell volume on temperature. The unit cell parameters a and c also increase linearly with the temperature. Despite the fact that the c parameter is substantially smaller than parameter a, it exhibits a significantly higher linear thermal expansion coefficient. Comparison between data obtained during heating and cooling indicates that the thermal expansion coefficient is slightly greater in the case of cooling. - Abstract: In situ X-ray diffraction experiments, using synchrotron radiation, were employed to analyze microstructure evolution of the 96.5Sn3Ag0.5Cu (wt.%)-SAC305 lead-free solder alloy during heating (30-240 deg. C), isothermal dwell (240 deg. C) and cooling (240-30 deg. C). The special emphasis was placed on the study of the melting and solidification processes, explaining formation, distribution and the order of crystallization of the crystal phases (β-Sn, intermetallic compounds) in the solder alloy. Furthermore, thermal expansion behaviour of the main constituent phase β-Sn was analyzed prior to melting and after the consequent solidification.

  17. Chip-olate’ and dry-film resists for efficient fabrication, singulation and sealing of microfluidic chips

    Science.gov (United States)

    Temiz, Yuksel; Delamarche, Emmanuel

    2014-09-01

    This paper describes a technique for high-throughput fabrication and efficient singulation of chips having closed microfluidic structures and takes advantage of dry-film resists (DFRs) for efficient sealing of capillary systems. The technique is illustrated using 4-inch Si/SiO2 wafers. Wafers carrying open microfluidic structures are partially diced to about half of their thickness. Treatments such as surface cleaning are done at wafer-level, then the structures are sealed using low-temperature (45 °C) lamination of a DFR that is pre-patterned using a craft cutter, and ready-to-use chips are finally separated manually like a chocolate bar by applying a small force (≤ 4 N). We further show that some DFRs have low auto-fluorescence at wavelengths typically used for common fluorescent dyes and that mechanical properties of some DFRs allow for the lamination of 200 μm wide microfluidic structures with negligible sagging (~1 μm). The hydrophilicity (advancing contact angle of ~60°) of the DFR supports autonomous capillary-driven flow without the need for additional surface treatment of the microfluidic chips. Flow rates from 1 to 5 µL min-1 are generated using different geometries of channels and capillary pumps. In addition, the ‘chip-olate’ technique is compatible with the patterning of capture antibodies on DFR for use in immunoassays. We believe this technique to be applicable to the fabrication of a wide range of microfluidic and lab-on-a-chip devices and to offer a viable alternative to many labor-intensive processes that are currently based on wafer bonding techniques or on the molding of poly(dimethylsiloxane) (PDMS) layers.

  18. Chip-olate’ and dry-film resists for efficient fabrication, singulation and sealing of microfluidic chips

    International Nuclear Information System (INIS)

    Temiz, Yuksel; Delamarche, Emmanuel

    2014-01-01

    This paper describes a technique for high-throughput fabrication and efficient singulation of chips having closed microfluidic structures and takes advantage of dry-film resists (DFRs) for efficient sealing of capillary systems. The technique is illustrated using 4-inch Si/SiO 2 wafers. Wafers carrying open microfluidic structures are partially diced to about half of their thickness. Treatments such as surface cleaning are done at wafer-level, then the structures are sealed using low-temperature (45 °C) lamination of a DFR that is pre-patterned using a craft cutter, and ready-to-use chips are finally separated manually like a chocolate bar by applying a small force (≤ 4 N). We further show that some DFRs have low auto-fluorescence at wavelengths typically used for common fluorescent dyes and that mechanical properties of some DFRs allow for the lamination of 200 μm wide microfluidic structures with negligible sagging (∼1 μm). The hydrophilicity (advancing contact angle of ∼60°) of the DFR supports autonomous capillary-driven flow without the need for additional surface treatment of the microfluidic chips. Flow rates from 1 to 5 µL min -1 are generated using different geometries of channels and capillary pumps. In addition, the ‘chip-olate’ technique is compatible with the patterning of capture antibodies on DFR for use in immunoassays. We believe this technique to be applicable to the fabrication of a wide range of microfluidic and lab-on-a-chip devices and to offer a viable alternative to many labor-intensive processes that are currently based on wafer bonding techniques or on the molding of poly(dimethylsiloxane) (PDMS) layers. (technical note)

  19. Damage Model for Reliability Assessment of Solder Joints in Wind Turbines

    DEFF Research Database (Denmark)

    Kostandyan, Erik; Sørensen, John Dalsgaard

    2012-01-01

    environmental factors. Reliability assessment for such type of products conventionally is performed by classical reliability techniques based on test data. Usually conventional reliability approaches are time and resource consuming activities. Thus in this paper we choose a physics of failure approach to define...... damage model by Miner’s rule. Our attention is focused on crack propagation in solder joints of electrical components due to the temperature loadings. Based on the proposed method it is described how to find the damage level for a given temperature loading profile. The proposed method is discussed...

  20. Decomposition studies of no-clean solder flux systems in connection with corrosion reliability of electronics

    DEFF Research Database (Denmark)

    Conseil, Helene; Jellesen, Morten Stendahl; Verdingovas, Vadimas

    2013-01-01

    with specific soldering process and parameters, while most important factors are the flux chemistry and its decomposition characteristics. Active parts of the flux residue can cause increased water absorption due to their hygroscopic nature and in solution they will increase leakage current and corrosion...... the contaminated PCBA parts to varying humidity and measuring the resulting leakage current. Results revealed a significant influence of flux chemistry including the amount of WOAs, while aggressiveness of the residue seems to vary with content and type of WOAs, and their nature of decomposition....

  1. Control of microstructure in soldered, brazed, welded, plated, cast or vapor deposited manufactured components

    Science.gov (United States)

    Ripley, Edward B.; Hallman, Russell L.

    2015-11-10

    Disclosed are methods and systems for controlling of the microstructures of a soldered, brazed, welded, plated, cast, or vapor deposited manufactured component. The systems typically use relatively weak magnetic fields of either constant or varying flux to affect material properties within a manufactured component, typically without modifying the alloy, or changing the chemical composition of materials or altering the time, temperature, or transformation parameters of a manufacturing process. Such systems and processes may be used with components consisting of only materials that are conventionally characterized as be uninfluenced by magnetic forces.

  2. Improved Switching Characteristics of Fast Power MOSFETs Applying Solder Bump Technology

    Directory of Open Access Journals (Sweden)

    Sibylle Dieckerhoff

    2008-01-01

    Full Text Available The impact of a reduced package stray inductance on the switching performance of fast power MOSFETs is discussed applying advanced 3D packaging technologies. Starting from an overview over new packaging approaches, a solder bump technology using a flexible PI substrate is exemplarily chosen for the evaluation. Measurement techniques to determine the stray inductance are discussed and compared with a numerical solution based on the PEEC method. Experimental results show the improvement of the voltage utilization while there is only a slight impact on total switching losses.

  3. In situ TEM observation of microcrack nucleation and propagation in pure tin solder

    International Nuclear Information System (INIS)

    Ding Ying; Wang Chunqing; Li, Mingyu; Wang Weiqiang

    2006-01-01

    Microcrack nucleation and propagation behavior in pure tin solder was investigated by using transmission electron microscopy (TEM) through in situ tensile test. Observation results showed that fracture process was completed in this visco-plastic material by connecting discontinuous cracks or voids. Depending on remarkable vacancy diffusion ability, microvoids were nucleated and developed in the dislocation free zone (DFZ) or super thinned area ahead of crack tip under local high stress concentration. The cracks were linked with each other by mutual dislocation emission which expedites the propagation of crack tips effectively

  4. Soldering Technology (6th) Proceedings of Annual Seminar, 17-18 February 1982.

    Science.gov (United States)

    1982-02-01

    aspect oF health and safety during this presentation. We are hoping that the work conducted by Van 2 Der Molen in the USA will clarify this issue. FLUX... Der Molen , PROC. OF 5th ANNUAL SEMINAR SOLDERING TECHNOLOGY, Naval Weapons Centre, China Lake, California, February 1981. 3. Burge, Perks, O’Brien...developed a new and innovative solution, which we believe to be a significant advance in the state of the art. In this new design (Fig.l) a FM DER

  5. BONDING ALUMINUM METALS

    Science.gov (United States)

    Noland, R.A.; Walker, D.E.

    1961-06-13

    A process is given for bonding aluminum to aluminum. Silicon powder is applied to at least one of the two surfaces of the two elements to be bonded, the two elements are assembled and rubbed against each other at room temperature whereby any oxide film is ruptured by the silicon crystals in the interface; thereafter heat and pressure are applied whereby an aluminum-silicon alloy is formed, squeezed out from the interface together with any oxide film, and the elements are bonded.

  6. Fabrication of Polymerase Chain Reaction Plastic Lab-on-a-Chip Device for Rapid Molecular Diagnoses

    Directory of Open Access Journals (Sweden)

    Kieu The Loan Trinh

    2016-05-01

    Full Text Available Purpose: We aim to fabricate a thermoplastic poly(methylmethacrylate (PMMA Lab-on-a-Chip device to perform continuous- flow polymerase chain reactions (PCRs for rapid molecular detection of foodborne pathogen bacteria. Methods: A miniaturized plastic device was fabricated by utilizing PMMA substrates mediated by poly(dimethylsiloxane interfacial coating, enabling bonding under mild conditions, and thus avoiding the deformation or collapse of microchannels. Surface characterizations were carried out and bond strength was measured. The feasibility of the Lab-on-a-Chip device for performing on-chip PCR utilizing a lab-made, portable dual heater was evaluated. The results were compared with those obtained using a commercially available thermal cycler. Results: A PMMA Lab-on-a-Chip device was designed and fabricated for conducting PCR using foodborne pathogens as sample targets. A robust bond was established between the PMMA substrates, which is essential for performing miniaturized PCR on plastic. The feasibility of on-chip PCR was evaluated using Escherichia coli O157:H7 and Cronobacter condimenti, two worldwide foodborne pathogens, and the target amplicons were successfully amplified within 25 minutes. Conclusions: In this study, we present a novel design of a low-cost and high-throughput thermoplastic PMMA Lab-on-a-Chip device for conducting microscale PCR, and we enable rapid molecular diagnoses of two important foodborne pathogens in minute resolution using this device. In this regard, the introduced highly portable system design has the potential to enable PCR investigations of many diseases quickly and accurately.

  7. Copper wire bonding

    CERN Document Server

    Chauhan, Preeti S; Zhong, ZhaoWei; Pecht, Michael G

    2014-01-01

    This critical volume provides an in-depth presentation of copper wire bonding technologies, processes and equipment, along with the economic benefits and risks.  Due to the increasing cost of materials used to make electronic components, the electronics industry has been rapidly moving from high cost gold to significantly lower cost copper as a wire bonding material.  However, copper wire bonding has several process and reliability concerns due to its material properties.  Copper Wire Bonding book lays out the challenges involved in replacing gold with copper as a wire bond material, and includes the bonding process changes—bond force, electric flame off, current and ultrasonic energy optimization, and bonding tools and equipment changes for first and second bond formation.  In addition, the bond–pad metallurgies and the use of bare and palladium-coated copper wires on aluminum are presented, and gold, nickel and palladium surface finishes are discussed.  The book also discusses best practices and re...

  8. Cache-aware network-on-chip for chip multiprocessors

    Science.gov (United States)

    Tatas, Konstantinos; Kyriacou, Costas; Dekoulis, George; Demetriou, Demetris; Avraam, Costas; Christou, Anastasia

    2009-05-01

    This paper presents the hardware prototype of a Network-on-Chip (NoC) for a chip multiprocessor that provides support for cache coherence, cache prefetching and cache-aware thread scheduling. A NoC with support to these cache related mechanisms can assist in improving systems performance by reducing the cache miss ratio. The presented multi-core system employs the Data-Driven Multithreading (DDM) model of execution. In DDM thread scheduling is done according to data availability, thus the system is aware of the threads to be executed in the near future. This characteristic of the DDM model allows for cache aware thread scheduling and cache prefetching. The NoC prototype is a crossbar switch with output buffering that can support a cache-aware 4-node chip multiprocessor. The prototype is built on the Xilinx ML506 board equipped with a Xilinx Virtex-5 FPGA.

  9. Atom chip gravimeter

    Science.gov (United States)

    Schubert, Christian; Abend, Sven; Gebbe, Martina; Gersemann, Matthias; Ahlers, Holger; Müntinga, Hauke; Matthias, Jonas; Sahelgozin, Maral; Herr, Waldemar; Lämmerzahl, Claus; Ertmer, Wolfgang; Rasel, Ernst

    2016-04-01

    Atom interferometry has developed into a tool for measuring rotations [1], accelerations [2], and testing fundamental physics [3]. Gravimeters based on laser cooled atoms demonstrated residual uncertainties of few microgal [2,4] and were simplified for field applications [5]. Atomic gravimeters rely on the interference of matter waves which are coherently manipulated by laser light fields. The latter can be interpreted as rulers to which the position of the atoms is compared. At three points in time separated by a free evolution, the light fields are pulsed onto the atoms. First, a coherent superposition of two momentum states is produced, then the momentum is inverted, and finally the two trajectories are recombined. Depending on the acceleration the atoms experienced, the number of atoms detected in the output ports will change. Consequently, the acceleration can be determined from the output signal. The laser cooled atoms with microkelvin temperatures used in state-of-the-art gravimeters impose limits on the accuracy [4]. Therefore, ultra-cold atoms generated by Bose-Einstein condensation and delta-kick collimation [6,7] are expected to be the key for further improvements. These sources suffered from a low flux implying an incompatible noise floor, but a competitive performance was demonstrated recently with atom chips [8]. In the compact and robust setup constructed for operation in the drop tower [6] we demonstrated all steps necessary for an atom chip gravimeter with Bose-Einstein condensates in a ground based operation. We will discuss the principle of operation, the current performance, and the perspectives to supersede the state of the art. The authors thank the QUANTUS cooperation for contributions to the drop tower project in the earlier stages. This work is supported by the German Space Agency (DLR) with funds provided by the Federal Ministry for Economic Affairs and Energy (BMWi) due to an enactment of the German Bundestag under grant numbers DLR 50WM

  10. Experiment list: SRX214075 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available age=Undifferentiated || treatment=Overexpress Sox17EK-V5 tagged || cell line=KH2 || chip antibody 1=none || chip antibody manufacture...r 1=none || chip antibody 2=V5 || chip antibody manufacture

  11. Experiment list: SRX122523 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ntibody=Irf2 || treatment=LPS || time=60 min || chip antibody manufacturer 1=Abcam || chip antibody catalog ...number 1=ab65048 || chip antibody manufacturer 2=Santa Cruz || chip antibody catalog number 2=sc-498 http://

  12. Experiment list: SRX122414 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ntibody=Junb || treatment=LPS || time=30 min || chip antibody manufacturer 1=Abcam || chip antibody catalog ...number 1=ab28838 || chip antibody manufacturer 2=Santa Cruz || chip antibody catalog number 2=sc-46 http://d

  13. Experiment list: SRX214071 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Undifferentiated || treatment=Overexpress Sox2-V5 tagged || cell line=KH2 || chip antibody 1=none || chip antibody manufacture...r 1=none || chip antibody 2=V5 || chip antibody manufacturer 2=

  14. Experiment list: SRX214086 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available entiated || cell line=KH2 || chip antibody 1=none || chip antibody manufacturer 1=none || chip antibody 2=none || chip antibody manuf...acturer 2=none http://dbarchive.biosciencedbc.jp/kyushu-

  15. Experiment list: SRX122485 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available antibody=Atf3 || treatment=LPS || time=120 min || chip antibody manufacturer 1=Santa Cruz || chip antibody ...catalog number 1=sc-188 || chip antibody manufacturer 2=Abcam || chip antibody catalog number 2=ab70005-100

  16. Experiment list: SRX122521 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ntibody=Irf2 || treatment=LPS || time=30 min || chip antibody manufacturer 1=Abcam || chip antibody catalog ...number 1=ab65048 || chip antibody manufacturer 2=Santa Cruz || chip antibody catalog number 2=sc-498 http://

  17. Experiment list: SRX122417 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ntibody=Junb || treatment=LPS || time=60 min || chip antibody manufacturer 1=Abcam || chip antibody catalog ...number 1=ab28838 || chip antibody manufacturer 2=Santa Cruz || chip antibody catalog number 2=sc-46 http://d

  18. Experiment list: SRX122520 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ntibody=Irf2 || treatment=LPS || time=30 min || chip antibody manufacturer 1=Abcam || chip antibody catalog ...number 1=ab65048 || chip antibody manufacturer 2=Santa Cruz || chip antibody catalog number 2=sc-498 http://

  19. Experiment list: SRX122413 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available antibody=Junb || treatment=LPS || time=120 min || chip antibody manufacturer 1=Abcam || chip antibody catalo...g number 1=ab28838 || chip antibody manufacturer 2=Santa Cruz || chip antibody catalog number 2=sc-46 http:/

  20. Experiment list: SRX122412 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available antibody=Junb || treatment=LPS || time=120 min || chip antibody manufacturer 1=Abcam || chip antibody catalo...g number 1=ab28838 || chip antibody manufacturer 2=Santa Cruz || chip antibody catalog number 2=sc-46 http:/

  1. Experiment list: SRX122406 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available antibody=Irf1 || treatment=LPS || time=0 min || chip antibody manufacturer 1=Abcam || chip antibody catalog... number 1=ab52520 || chip antibody manufacturer 2=Santa Cruz || chip antibody catalog number 2=sc-640 http:/

  2. Experiment list: SRX122415 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ntibody=Junb || treatment=LPS || time=30 min || chip antibody manufacturer 1=Abcam || chip antibody catalog ...number 1=ab28838 || chip antibody manufacturer 2=Santa Cruz || chip antibody catalog number 2=sc-46 http://d

  3. Experiment list: SRX214074 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ge=Undifferentiated || treatment=Overexpress Sox17EK-V5 tagged || cell line=KH2 || chip antibody 1=none || chip antibody manufacture...r 1=none || chip antibody 2=V5 || chip antibody manufacture

  4. Experiment list: SRX214072 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available e=Undifferentiated || treatment=Overexpress Sox2KE-V5 tagged || cell line=KH2 || chip antibody 1=none || chip antibody manufacture...r 1=none || chip antibody 2=V5 || chip antibody manufacture

  5. Experiment list: SRX214067 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available fferentiated || cell line=F9 || chip antibody 1=Pou5f1/Oct4 || chip antibody manufacture...r 1=Santa Cruz || chip antibody 2=none || chip antibody manufacturer 2=none http://dbarchive.bioscien

  6. Experiment list: SRX122416 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ntibody=Junb || treatment=LPS || time=60 min || chip antibody manufacturer 1=Abcam || chip antibody catalog ...number 1=ab28838 || chip antibody manufacturer 2=Santa Cruz || chip antibody catalog number 2=sc-46 http://d

  7. Experiment list: SRX122565 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available antibody=Stat2 || treatment=LPS || time=0 min || chip antibody manufacturer 1=Abcam || chip antibody catalog... number 1=ab53149 || chip antibody manufacturer 2=Santa Cruz || chip antibody catalog number 2=sc-839 http:/

  8. Chip compacting press; Jido kirikuzu asshukuki

    Energy Technology Data Exchange (ETDEWEB)

    Oura, K. [Yuken Kogyo Co. Ltd., Kanagawa (Japan)

    1998-08-15

    The chips exhausted from various machine tools are massy, occupy much space and make working environment worse by staying added cutting oil to lower part. The chips are exhausted as a result of machining and have not constant quality. Even if used material is same the chips have various shapes and properties by kinds and machining methods of used machine tools, and are troublesome materials from a standpoint of their treatment. Pressing and solidification of the chips have frequently been tried. A chip compacting press introduced in this paper, a relatively cheap chip compacting press aimed for relatively small scale chip treatment, and has such characteristics and effects as follows. Chips are pressed and solidified by each raw material, so fractional management can be easily conducted. As casting metal chips and curled chips of iron and aluminum can be pressed to about 1/3 to 1/5 and about 1/40, respectively, space saving can be conducted. Chip compacting pressing upgrades its transporting efficiency to make possible to reduce its transporting cost. As chip solidification controls its oxidation and most cutting oil are removed, chips are easy to recycle. 2 figs., 1 tab.

  9. Polydimethylsiloxane-integratable micropressure sensor for microfluidic chips

    KAUST Repository

    Wang, Limu

    2009-09-17

    A novel microfluidicpressuresensor which can be fully integrated into polydimethylsiloxane(PDMS) is reported. The sensor produces electrical signals directly. We integrated PDMS-based conductive composites into a 30 μm thick membrane and bonded it to the microchannel side wall. The response time of the sensor is approximately 100 ms and can work within a pressure range as wide as 0–100 kPa. The resolution of this micropressure sensor is generally 0.1 kPa but can be increased to 0.01 kPa at high pressures as a result of the quadratic relationship between resistance and pressure. The PDMS-based nature of the sensor ensures its perfect bonding with PDMS chips, and the standard photolithographic process of the sensor allows one-time fabrication of three dimensional structures or even microsensor arrays. The theoretical calculations are in good agreement with experimental observations.

  10. Polydimethylsiloxane-integratable micropressure sensor for microfluidic chips

    KAUST Repository

    Wang, Limu; Zhang, Mengying; Yang, Min; Zhu, Weiming; Wu, Jinbo; Gong, Xiuqing; Wen, Weijia

    2009-01-01

    A novel microfluidicpressuresensor which can be fully integrated into polydimethylsiloxane(PDMS) is reported. The sensor produces electrical signals directly. We integrated PDMS-based conductive composites into a 30 μm thick membrane and bonded it to the microchannel side wall. The response time of the sensor is approximately 100 ms and can work within a pressure range as wide as 0–100 kPa. The resolution of this micropressure sensor is generally 0.1 kPa but can be increased to 0.01 kPa at high pressures as a result of the quadratic relationship between resistance and pressure. The PDMS-based nature of the sensor ensures its perfect bonding with PDMS chips, and the standard photolithographic process of the sensor allows one-time fabrication of three dimensional structures or even microsensor arrays. The theoretical calculations are in good agreement with experimental observations.

  11. Probing and irradiation tests of ALICE pixel chip wafers and sensors

    CERN Document Server

    Cinausero, M; Antinori, F; Chochula, P; Dinapoli, R; Dima, R; Fabris, D; Galet, G; Lunardon, M; Manea, C; Marchini, S; Martini, S; Moretto, S; Pepato, Adriano; Prete, G; Riedler, P; Scarlassara, F; Segato, G F; Soramel, F; Stefanini, G; Turrisi, R; Vannucci, L; Viesti, G

    2004-01-01

    In the framework of the ALICE Silicon Pixel Detector (SPD) project a system dedicated to the tests of the ALICE1LHCb chip wafers has been assembled and is now in use for the selection of pixel chips to be bump-bonded to sensor ladders. In parallel, radiation hardness tests of the SPD silicon sensors have been carried out using the 27 MeV proton beam delivered by the XTU TANDEM accelerator at the SIRAD facility in LNL. In this paper we describe the wafer probing and irradiation set-ups and we report the obtained results. (6 refs).

  12. Systematics of Structural, Phase Stability, and Cohesive Properties of η'-Cu6(Sn,In)5 Compounds Occurring in In-Sn/Cu Solder Joints

    Science.gov (United States)

    Ramos, S. B.; González Lemus, N. V.; Deluque Toro, C. E.; Cabeza, G. F.; Fernández Guillermet, A.

    2017-07-01

    Motivated by the high solubility of In in ( mC44) η'-Cu6Sn5 compound as well as the occurrence of an In-doped η'-intermetallic in the microstructure of Cu/In-Sn/Cu solder joints, a theoretical study has been carried out to investigate the various physical effects of incorporating In at Sn Wyckoff sites of the binary η'-phase. Systematic ab initio calculations using the projected augmented wave method and Vienna Ab initio Simulation Package were used to determine the composition dependence of the structural and cohesive properties of η'-Cu6(Sn,In)5 compounds, compared with those expected from the binary end-member compounds Cu6Sn5 and Cu6In5. The molar volume shows significant deviations from Vegard's law. The predicted composition dependence of the cohesive properties is discussed using two complementary approaches, viz. a valence-electron density approach as well as a bond-number approach, both accounting for the roughly linear dependence of the cohesive energy on the In content. A microscopic interpretation for this general trend is given in terms of the key contributions to chemical bonding in this class of compounds, namely Cu d-electron overlap and hybridization of Cu d-states with In and Sn p-electron states. Moreover, a crystallographic site approach is developed to accurately establish the phase-stabilizing effect of incorporating In at specific Wyckoff positions of the ( mC44) η'-Cu6Sn5 structure.

  13. Route to one-step microstructure mold fabrication for PDMS microfluidic chip

    Science.gov (United States)

    Lv, Xiaoqing; Geng, Zhaoxin; Fan, Zhiyuan; Wang, Shicai; Su, Yue; Fang, Weihao; Pei, Weihua; Chen, Hongda

    2018-04-01

    The microstructure mold fabrication for PDMS microfluidic chip remains complex and time-consuming process requiring special equipment and protocols: photolithography and etching. Thus, a rapid and cost-effective method is highly needed. Comparing with the traditional microfluidic chip fabricating process based on the micro-electromechanical system (MEMS), this method is simple and easy to implement, and the whole fabrication process only requires 1-2 h. Different size of microstructure from 100 to 1000 μm was fabricated, and used to culture four kinds of breast cancer cell lines. Cell viability and morphology was assessed when they were cultured in the micro straight channels, micro square holes and the bonding PDMS-glass microfluidic chip. The experimental results indicate that the microfluidic chip is good and meet the experimental requirements. This method can greatly reduce the process time and cost of the microfluidic chip, and provide a simple and effective way for the structure design and in the field of biological microfabrications and microfluidic chips.

  14. STUDY OF CHIP IGNITION AND CHIP MORPHOLOGY AFTER MILLING OF MAGNESIUM ALLOYS

    Directory of Open Access Journals (Sweden)

    Ireneusz Zagórski

    2016-12-01

    Full Text Available The paper analyses the impact of specified technological parameters of milling (vc, fz, ap on time to ignition. Stages leading to chip ignition were analysed. Metallographic images of magnesium chip were presented. No significant difference was observed in time to ignition in different chip fractions. Moreover, the surface of chips was free of products of ignition and signs of strong oxidation.

  15. Transversely Compressed Bonded Joints

    DEFF Research Database (Denmark)

    Hansen, Christian Skodborg; Schmidt, Jacob Wittrup; Stang, Henrik

    2012-01-01

    The load capacity of bonded joints can be increased if transverse pressure is applied at the interface. The transverse pressure is assumed to introduce a Coulomb-friction contribution to the cohesive law for the interface. Response and load capacity for a bonded single-lap joint was derived using...

  16. Miniaturization of Micro-Solder Bumps and Effect of IMC on Stress Distribution

    Science.gov (United States)

    Choudhury, Soud Farhan; Ladani, Leila

    2016-07-01

    As the joints become smaller in more advanced packages and devices, intermetallic (IMCs) volume ratio increases, which significantly impacts the overall mechanical behavior of joints. The existence of only a few grains of Sn (Tin) and IMC materials results in anisotropic elastic and plastic behavior which is not detectable using conventional finite element (FE) simulation with average properties for polycrystalline material. In this study, crystal plasticity finite element (CPFE) simulation is used to model the whole joint including copper, Sn solder and Cu6Sn5 IMC material. Experimental lap-shear test results for solder joints from the literature were used to validate the models. A comparative analysis between traditional FE, CPFE and experiments was conducted. The CPFE model was able to correlate the experiments more closely compared to traditional FE analysis because of its ability to capture micro-mechanical anisotropic behavior. Further analysis was conducted to evaluate the effect of IMC thickness on stress distribution in micro-bumps using a systematic numerical experiment with IMC thickness ranging from 0% to 80%. The analysis was conducted on micro-bumps with single crystal Sn and bicrystal Sn. The overall stress distribution and shear deformation changes as the IMC thickness increases. The model with higher IMC thickness shows a stiffer shear response, and provides a higher shear yield strength.

  17. Soldered Power Arm: An Easy and Effective Method for Intrusion and Retraction of Anterior Teeth

    Directory of Open Access Journals (Sweden)

    Ketan K Vakil

    2014-01-01

    Full Text Available The orthodontic correction of deep overbite can be achieved with several mechanisms that will result in true intrusion of anterior teeth, extrusion of posterior teeth, or a combination of both. For the orthodontic correction of bimaxillary dentoalveolar protrusion with deep bite, there are several treatment modalities like segmented arch approach, retraction and intrusion utility arches, temporary anchorage devices. Though not a novel therapeutic concept, the use of miniscrew implants to obtain absolute anchorage has recently become very popular in clinical orthodontic approaches. To allow the use of sliding mechanics for bodily retraction with intrusion of anterior teeth, we devised a soldered power arm (SPA on standard molar tube. It is simple, stable, precise and effective in cases where anterior teeth need to be simultaneously retracted and intruded. A power arm can be readily fabricated from 20 gauge stainless steel wire and soldered on the molar buccal tube so as to avoid any distortion or loosening of power arm from molar tube during the course of the treatment. The SPA works efficiently with the molar being stabilized in all three planes of space. The resultant force vector is directed more apically toward the center of resistance of the anchor unit, which resulted in the treatment outcome of retraction and intrusion of the anterior teeth and correction of the deep bite.

  18. Electromigration in 3D-IC scale Cu/Sn/Cu solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Cheng-En, E-mail: ceho1975@hotmail.com; Lee, Pei-Tzu; Chen, Chih-Nan; Yang, Cheng-Hsien

    2016-08-15

    The electromigration effect on the three-dimensional integrated circuits (3D-IC) scale solder joints with a Cu/Sn(25–50 μm)/Cu configuration was investigated using a field-emission scanning electron microscope (FE–SEM) combined with electron backscatter diffraction (EBSD) analysis system. Electron current stressing for a few days caused the pronounced accumulation of Cu{sub 6}Sn{sub 5} in specific Sn grain boundaries (GBs). The EBSD analysis indicated that both the β-Sn crystallographic orientation and GB orientation play dominant roles in this accumulation. The dependencies of the Cu{sub 6}Sn{sub 5} accumulation on the two above factors (i.e., Sn grain orientation and GB orientation) can be well rationalized via a proposed mathematic model based on the Huntington and Grone's electromigration theory with the Cu anisotropic diffusion data in a β-Sn lattice. - Highlights: • Anisotropic Cu electromigration in the 3D-IC scale microelectronic solder joints. • Pronounced accumulation of Cu{sub 6}Sn{sub 5} intermetallic in specific Sn grain boundaries. • A linear dependence of Cu{sub 6}Sn{sub 5} accumulation over the current stressing time. • β-Sn and grain boundary orientations are the dominant factors in Cu{sub 6}Sn{sub 5} accumulation.

  19. Interactions of Cu-substrates with titanium-alloyed Sn-Zn solders

    Directory of Open Access Journals (Sweden)

    Soares D.

    2006-01-01

    Full Text Available The interactions of copper substrate with titanium-alloyed Sn-Zn eutectic solders have been studied. Two series of experiments have been performed. The first one consisted in differential thermal analyses of Sn-Zn nearly eutectic alloys containing from 1.3 to 2.2 wt. % Ti. Diffusion couples consisted of Cu-wires and Sn-Zn-Ti liquid solders, produced at 250 and 275 OC have been prepared in the second series,. The contact times were up to 3600 s. The contact zones have been characterized by optical and scanning electron microscope. Two layers have been found along the interfaces solid/liquid. The first and the second layers are identical, respectively, with γ and ε phases of the Cu-Zn system. No changes of the chemical compositions were detected for the tested temperatures and reaction times. Continuous parabolic growth of the total diffusion zone thickness with the time of diffusion is observed. The growth is due mainly to one the formed layers (γ while the thickness of the ε-phase layer, stays almost constant for all tested diffusion times and temperatures.

  20. Economical surface treatment of die casting dies to prevent soldering in high pressure casting

    International Nuclear Information System (INIS)

    Fraser, D.T.; Jahedi, M.Z.

    2001-01-01

    This paper describes the use of a gas oxidation treatment of H13 tool steel to develop a compact iron oxide layer at the surface of core pins to prevent soldering in high pressure die casting. The performance of oxide layers in the protection of die steel against soldering during high pressure die casting was tested in a specially designed die using removable core pins and Al-11 Si-3 Cu casting alloy. The gas oxidation treatment can be applied at low temperatures and to large areas of the die surface. In addition this process is very cost effective compared to other coating processes such as physical vapour deposition (PVD), or thermo-reactive diffusion (TRD) coatings. This work demonstrated that surface treatment producing pure magnetite (Fe 3 O 4 ) layers are more protective than oxide layers containing a combination of Fe 3 O 4 (magnetite) and Fe 3 O 3 (haematite). The magnetite layer acts as a barrier between the die steel/casting alloy interface and prevents the formation of inter-metallic phases. Optical microscopy and scanning electron microscope were used to determine the thickness of the oxide layer, while X-ray diffraction was performed to determine the oxide phase structure

  1. High-sensitivity low-noise miniature fluxgate magnetometers using a flip chip conceptual design.

    Science.gov (United States)

    Lu, Chih-Cheng; Huang, Jeff; Chiu, Po-Kai; Chiu, Shih-Liang; Jeng, Jen-Tzong

    2014-07-30

    This paper presents a novel class of miniature fluxgate magnetometers fabricated on a print circuit board (PCB) substrate and electrically connected to each other similar to the current "flip chip" concept in semiconductor package. This sensor is soldered together by reversely flipping a 5 cm × 3 cm PCB substrate to the other identical one which includes dual magnetic cores, planar pick-up coils, and 3-D excitation coils constructed by planar Cu interconnections patterned on PCB substrates. Principles and analysis of the fluxgate sensor are introduced first, and followed by FEA electromagnetic modeling and simulation for the proposed sensor. Comprehensive characteristic experiments of the miniature fluxgate device exhibit favorable results in terms of sensitivity (or "responsivity" for magnetometers) and field noise spectrum. The sensor is driven and characterized by employing the improved second-harmonic detection technique that enables linear V-B correlation and responsivity verification. In addition, the double magnitude of responsivity measured under very low frequency (1 Hz) magnetic fields is experimentally demonstrated. As a result, the maximum responsivity of 593 V/T occurs at 50 kHz of excitation frequency with the second harmonic wave of excitation; however, the minimum magnetic field noise is found to be 0.05 nT/Hz(1/2) at 1 Hz under the same excitation. In comparison with other miniature planar fluxgates published to date, the fluxgate magnetic sensor with flip chip configuration offers advances in both device functionality and fabrication simplicity. More importantly, the novel design can be further extended to a silicon-based micro-fluxgate chip manufactured by emerging CMOS-MEMS technologies, thus enriching its potential range of applications in modern engineering and the consumer electronics market.

  2. Assessment of the effects of the Japanese shift to lead-free solders and its impact on material substitution and environmental emissions by a dynamic material flow analysis

    International Nuclear Information System (INIS)

    Fuse, Masaaki; Tsunemi, Kiyotaka

    2012-01-01

    Lead-free electronics has been extensively studied, whereas their adoption by society and their impact on material substitution and environmental emissions are not well understood. Through a material flow analysis (MFA), this paper explores the life cycle flows for solder-containing metals in Japan, which leads the world in the shift to lead-free solders in electronics. The results indicate that the shift has been progressing rapidly for a decade, and that substitutes for lead in solders, which include silver and copper, are still in the early life cycle stages. The results also show, however, that such substitution slows down during the late life cycle stages owing to long electronic product lifespans. This deceleration of material substitution in the solder life cycle may not only preclude a reduction in lead emissions to air but also accelerate an increase in silver emissions to air and water. As an effective measure against ongoing lead emissions, our scenario analysis suggests an aggressive recycling program for printed circuit boards that utilizes an existing recycling scheme. -- Highlights: ► We model the life cycle flows for solder-containing metals in Japan. ► The Japanese shift to lead-free solders progresses rapidly for a decade. ► Substitution for lead in solders slows down during the late life cycle stages. ► The deceleration of substitution precludes a reduction in lead emissions to air.

  3. The Shear Strength and Fracture Behavior of Sn-Ag- xSb Solder Joints with Au/Ni-P/Cu UBM

    Science.gov (United States)

    Lee, Hwa-Teng; Hu, Shuen-Yuan; Hong, Ting-Fu; Chen, Yin-Fa

    2008-06-01

    This study investigates the effects of Sb addition on the shear strength and fracture behavior of Sn-Ag-based solders with Au/Ni-P/Cu underbump metallization (UBM) substrates. Sn-3Ag- xSb ternary alloy solder joints were prepared by adding 0 wt.% to 10 wt.% Sb to a Sn-3.5Ag alloy and joining them with Au/Ni-P/Cu UBM substrates. The solder joints were isothermally stored at 150°C for up to 625 h to study their microstructure and interfacial reaction with the UBM. Single-lap shear tests were conducted to evaluate the mechanical properties, thermal resistance, and failure behavior. The results show that UBM effectively suppressed intermetallic compound (IMC) formation and growth during isothermal storage. The Sb addition helped to refine the Ag3Sn compounds, further improving the shear strength and thermal resistance of the solders. The fracture behavior evolved from solder mode toward the mixed mode and finally to the IMC mode with increasing added Sb and isothermal storage time. However, SnSb compounds were found in the solder with 10 wt.% Sb; they may cause mechanical degradation of the solder after long-term isothermal storage.

  4. Corporate Bonds in Denmark

    DEFF Research Database (Denmark)

    Tell, Michael

    2015-01-01

    Corporate financing is the choice between capital generated by the corporation and capital from external investors. However, since the financial crisis shook the markets in 2007–2008, financing opportunities through the classical means of financing have decreased. As a result, corporations have...... to think in alternative ways such as issuing corporate bonds. A market for corporate bonds exists in countries such as Norway, Germany, France, the United Kingdom and the United States, while Denmark is still behind in this trend. Some large Danish corporations have instead used foreign corporate bonds...... markets. However, NASDAQ OMX has introduced the First North Bond Market in December 2012 and new regulatory framework came into place in 2014, which may contribute to a Danish based corporate bond market. The purpose of this article is to present the regulatory changes in Denmark in relation to corporate...

  5. CMOS foveal image sensor chip

    Science.gov (United States)

    Bandera, Cesar (Inventor); Scott, Peter (Inventor); Sridhar, Ramalingam (Inventor); Xia, Shu (Inventor)

    2002-01-01

    A foveal image sensor integrated circuit comprising a plurality of CMOS active pixel sensors arranged both within and about a central fovea region of the chip. The pixels in the central fovea region have a smaller size than the pixels arranged in peripheral rings about the central region. A new photocharge normalization scheme and associated circuitry normalizes the output signals from the different size pixels in the array. The pixels are assembled into a multi-resolution rectilinear foveal image sensor chip using a novel access scheme to reduce the number of analog RAM cells needed. Localized spatial resolution declines monotonically with offset from the imager's optical axis, analogous to biological foveal vision.

  6. An electrochromatography chip with integrated waveguides for UV absorbance detection

    International Nuclear Information System (INIS)

    Gustafsson, O; Mogensen, K B; Ohlsson, P D; Kutter, J P; Liu, Y; Jacobson, S C

    2008-01-01

    A silicon-based microchip for electrochromatographic separations is presented. Apart from a microfluidic network, the microchip has integrated UV-transparent waveguides for detection and integrated couplers for optical fibers on the chip, yielding the most complete chromatography microchip to date in terms of the integration of optical components. The microfluidic network and the optical components are fabricated in a single etching step in silicon and subsequently thermally oxidized. The separation column consists of a regular array of microfabricated solid support structures with a monolayer of an octylsilane covalently bonded to the surfaces to provide chromatographic interaction. The chip features a 1 mm long U-shaped detection cell and planar silicon dioxide waveguides that couple light to and from the detection cell. Microfabricated on-chip fiber couplers assure perfect alignment of optical fibers to the waveguides. The entire oxidized silicon microchip structure is sealed with a glass lid. Reversed phase electrochromatographic separation of three neutral compounds is demonstrated using UV absorbance detection at 254 nm. Baseline separation of the analytes is achieved in less than two minutes

  7. Space division multiplexing chip-to-chip quantum key distribution

    DEFF Research Database (Denmark)

    Bacco, Davide; Ding, Yunhong; Dalgaard, Kjeld

    2017-01-01

    nodes of the quantum keys to their respective destinations. In this paper we present an experimental demonstration of a photonic integrated silicon chip quantum key distribution protocols based on space division multiplexing (SDM), through multicore fiber technology. Parallel and independent quantum...

  8. Effect of cooling rate during solidification of Sn-9Zn lead-free solder alloy on its microstructure, tensile strength and ductile-brittle transition temperature

    Energy Technology Data Exchange (ETDEWEB)

    Prabhu, K.N., E-mail: prabhukn_2002@yahoo.co.in [Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal, Mangalore 575 025 (India); Deshapande, Parashuram; Satyanarayan [Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal, Mangalore 575 025 (India)

    2012-01-30

    Highlights: Black-Right-Pointing-Pointer Effect of cooling rate on tensile and impact properties of Sn-9Zn alloy was assessed. Black-Right-Pointing-Pointer Both DBTT and UTS of the solder alloy increased with increase in cooling rate. Black-Right-Pointing-Pointer An optimum cooling rate during solidification would minimize DBTT and maximize UTS. - Abstract: Solidification rate is an important variable during processing of materials, including soldering, involving solidification. The rate of solidification controls the metallurgical microstructure at the solder joint and hence the mechanical properties. A high tensile strength and a lower ductile-brittle transition temperature are necessary for reliability of solder joints in electronic circuits. Hence in the present work, the effect of cooling rate during solidification on microstructure, impact and tensile properties of Sn-9Zn lead-free solder alloy was investigated. Four different cooling media (copper and stainless steel moulds, air and furnace cooling) were used for solidification to achieve different cooling rates. Solder alloy solidified in copper mould exhibited higher cooling rate as compared to other cooling media. The microstructure is refined as the cooling rate was increased from 0.03 to 25 Degree-Sign C/s. With increase in cooling rate it was observed that the size of Zn flakes became finer and distributed uniformly throughout the matrix. Ductile-to-brittle transition temperature (DBTT) of the solder alloy increased with increase in cooling rate. Fractured surfaces of impact test specimens showed cleavage like appearance and river like pattern at very low temperatures and dimple like appearance at higher temperatures. The tensile strength of the solder alloy solidified in Cu and stainless moulds were higher as compared to air and furnace cooled samples. It is therefore suggested that the cooling rate during solidification of the solder alloy should be optimum to maximize the strength and minimize the

  9. Effect of cooling rate during solidification of Sn–9Zn lead-free solder alloy on its microstructure, tensile strength and ductile–brittle transition temperature

    International Nuclear Information System (INIS)

    Prabhu, K.N.; Deshapande, Parashuram; Satyanarayan

    2012-01-01

    Highlights: ► Effect of cooling rate on tensile and impact properties of Sn–9Zn alloy was assessed. ► Both DBTT and UTS of the solder alloy increased with increase in cooling rate. ► An optimum cooling rate during solidification would minimize DBTT and maximize UTS. - Abstract: Solidification rate is an important variable during processing of materials, including soldering, involving solidification. The rate of solidification controls the metallurgical microstructure at the solder joint and hence the mechanical properties. A high tensile strength and a lower ductile–brittle transition temperature are necessary for reliability of solder joints in electronic circuits. Hence in the present work, the effect of cooling rate during solidification on microstructure, impact and tensile properties of Sn–9Zn lead-free solder alloy was investigated. Four different cooling media (copper and stainless steel moulds, air and furnace cooling) were used for solidification to achieve different cooling rates. Solder alloy solidified in copper mould exhibited higher cooling rate as compared to other cooling media. The microstructure is refined as the cooling rate was increased from 0.03 to 25 °C/s. With increase in cooling rate it was observed that the size of Zn flakes became finer and distributed uniformly throughout the matrix. Ductile-to-brittle transition temperature (DBTT) of the solder alloy increased with increase in cooling rate. Fractured surfaces of impact test specimens showed cleavage like appearance and river like pattern at very low temperatures and dimple like appearance at higher temperatures. The tensile strength of the solder alloy solidified in Cu and stainless moulds were higher as compared to air and furnace cooled samples. It is therefore suggested that the cooling rate during solidification of the solder alloy should be optimum to maximize the strength and minimize the DBTT.

  10. Influence of passivation process on chip performance

    NARCIS (Netherlands)

    Lu, J.; Kovalgin, Alexeij Y.; Schmitz, Jurriaan

    2009-01-01

    In this work, we have studied the performance of CMOS chips before and after a low temperature post-processing step. In order to prevent damage to the IC chips by the post-processing steps, a first passivation layers is needed on top of the IC chips. Two different passivation layer deposition

  11. Interfacial Microstructure and Shear Strength of Brazed Cu-Cr-Zr Alloy Cylinder and Cylindrical Hole by Au Based Solder

    Directory of Open Access Journals (Sweden)

    Zaihua Li

    2017-07-01

    Full Text Available Au-Ge-Ni solder was chosen for brazing of the Cu-Cr-Zr alloy cylinder and a part with a cylindrical hole (sleeve below 550 °C. The Au based solder was first sintered on the surface of the cylinder and then brazed to the inner surface of the sleeve. The effects of the heating process, the temperature and the holding time at the temperature on the microstructure of the sintered layer on the surface of the cylinder, the brazed interfacial microstructure, and the brazed shear strength between the cylinder and the sleeve were investigated by scanning electron microscope, energy dispersive X-ray spectroscopy analysis, and tensile shear tests. By approach of side solder melt feeding and brazing under proper parameters, the voids and micro cracks due to a lack of enough solder melt feeding are greatly lessened and the brazed shear strength of 100 MPa is ensured even with large clearances around 0.01 mm.

  12. Three-dimensional (3D) visualization of reflow porosity and modeling of deformation in Pb-free solder joints

    International Nuclear Information System (INIS)

    Dudek, M.A.; Hunter, L.; Kranz, S.; Williams, J.J.; Lau, S.H.; Chawla, N.

    2010-01-01

    The volume, size, and dispersion of porosity in solder joints are known to affect mechanical performance and reliability. Most of the techniques used to characterize the three-dimensional (3D) nature of these defects are destructive. With the enhancements in high resolution computed tomography (CT), the detection limits of intrinsic microstructures have been significantly improved. Furthermore, the 3D microstructure of the material can be used in finite element models to understand their effect on microscopic deformation. In this paper we describe a technique utilizing high resolution (< 1 μm) X-ray tomography for the three-dimensional (3D) visualization of pores in Sn-3.9Ag-0.7Cu/Cu joints. The characteristics of reflow porosity, including volume fraction and distribution, were investigated for two reflow profiles. The size and distribution of porosity size were visualized in 3D for four different solder joints. In addition, the 3D virtual microstructure was incorporated into a finite element model to quantify the effect of voids on the lap shear behavior of a solder joint. The presence, size, and location of voids significantly increased the severity of strain localization at the solder/copper interface.

  13. In-situ Investigation of Lead-free Solder Alloy Formation Using a Hot-plate Microscope

    DEFF Research Database (Denmark)

    Bergmann, René; Tang, Peter Torben; Hansen, Hans Nørgaard

    2007-01-01

    This work presents the advantages of using a hot-plate microscope for investigation of new (high-temperature) lead- free solders as in-situ analysis tool and preparation equipment. A description of the equipment and the preparation method is given and some examples are outlined. The formation...

  14. Studies of IBL wire bonds operation in a ATLAS-like magnetic field.

    CERN Document Server

    Alvarez Feito, D; Mandelli, B

    2015-01-01

    At the Large Hadron Collider (LHC) experiments, most of silicon detectors use wire bonds to connect front-end chips and sensors to circuit boards for the data and service trans- missions. These wire bonds are operated in strong magnetic field environments and if time varying currents pass through them with frequencies close to their mechanical resonance frequency, strong resonant oscillations may occur. Under certain conditions, this effect can lead to fatigue stress and eventually breakage of wire bonds. During the first LHC Long Shutdown, the ATLAS Pixel Detector has been upgraded with the addition of a fourth innermost layer, the Insertable B-Layer (IBL), which has more than 50000 wire bonds operated in the ATLAS 2 T magnetic field. The results of systematic studies of operating wire bonds under IBL-like conditions are presented. Two different solutions have been investigated to minimize the oscillation amplitude of wire bonds.

  15. Ultracold atoms on atom chips

    DEFF Research Database (Denmark)

    Krüger, Peter; Hofferberth, S.; Haller, E.

    2005-01-01

    Miniaturized potentials near the surface of atom chips can be used as flexible and versatile tools for the manipulation of ultracold atoms on a microscale. The full scope of possibilities is only accessible if atom-surface distances can be reduced to microns. We discuss experiments in this regime...

  16. FERMI multi-chip module

    CERN Multimedia

    This FERMI multi-chip module contains five million transistors. 25 000 of these modules will handle the flood of information through parts of the ATLAS and CMS detectors at the LHC. To select interesting events for recording, crucial decisions are taken before the data leaves the detector. FERMI modules are being developed at CERN in partnership with European industry.

  17. Tunable on chip optofluidic laser

    DEFF Research Database (Denmark)

    Bakal, Avraham; Vannahme, Christoph; Kristensen, Anders

    2015-01-01

    A chip scale tunable laser in the visible spectral band is realized by generating a periodic droplet array inside a microfluidic channel. Combined with a gain medium within the droplets, the periodic structure provides the optical feedback of the laser. By controlling the pressure applied to two...

  18. Chip & Cut Tests an Elastomeren

    OpenAIRE

    Euchler, Eric; Heinrich, Gert; Michael, Hannes; Gehde, Michael; Stocek, Radek; Kratina, Ondrej; Kipscholl, Reinhold

    2016-01-01

    Dieser Vortrag stellt einen neuartigen Prüfstand vor, mit welchem das Chip & Cut Verhalten von Elastomeren charakterisiert werden kann. Sowohl theoretischer Hintergrund als auch praktische Erkenntnisse werden diskutiert. Die Vorstellung der Praxisrelevanz dieser Untersuchungen steht im Fokus des Vortrags.

  19. Low-temperature, simple and fast integration technique of microfluidic chips by using a UV-curable adhesive

    NARCIS (Netherlands)

    Arayanarakool, Rerngchai; le Gac, Severine; van den Berg, Albert

    2010-01-01

    In the fields of MicroElectroMechanical Systems (MEMS) and Lab On a Chip (LOC), a device is often fabricated using diverse substrates which are processed separately and finally assembled together using a bonding process to yield the final device. Here we describe and demonstrate a novel

  20. Optical lattice on an atom chip

    DEFF Research Database (Denmark)

    Gallego, D.; Hofferberth, S.; Schumm, Thorsten

    2009-01-01

    Optical dipole traps and atom chips are two very powerful tools for the quantum manipulation of neutral atoms. We demonstrate that both methods can be combined by creating an optical lattice potential on an atom chip. A red-detuned laser beam is retroreflected using the atom chip surface as a high......-quality mirror, generating a vertical array of purely optical oblate traps. We transfer thermal atoms from the chip into the lattice and observe cooling into the two-dimensional regime. Using a chip-generated Bose-Einstein condensate, we demonstrate coherent Bloch oscillations in the lattice....

  1. Fabrication of All Glass Bifurcation Microfluidic Chip for Blood Plasma Separation

    Directory of Open Access Journals (Sweden)

    Hyungjun Jang

    2017-02-01

    Full Text Available An all-glass bifurcation microfluidic chip for blood plasma separation was fabricated by a cost-effective glass molding process using an amorphous carbon (AC mold, which in turn was fabricated by the carbonization of a replicated furan precursor. To compensate for the shrinkage during AC mold fabrication, an enlarged photoresist pattern master was designed, and an AC mold with a dimensional error of 2.9% was achieved; the dimensional error of the master pattern was 1.6%. In the glass molding process, a glass microchannel plate with negligible shape errors (~1.5% compared to AC mold was replicated. Finally, an all-glass bifurcation microfluidic chip was realized by micro drilling and thermal fusion bonding processes. A separation efficiency of 74% was obtained using the fabricated all-glass bifurcation microfluidic chip.

  2. Transparent polymeric cell culture chip with integrated temperature control and uniform media perfusion

    DEFF Research Database (Denmark)

    Petronis, Sarunas; Stangegaard, Michael; Christensen, C.

    2006-01-01

    Modern microfabrication and microfluidic technologies offer new opportunities in the design and fabrication of miniaturized cell culture systems for online monitoring of living cells. We used laser micromachining and thermal bonding to fabricate an optically transparent, low-cost polymeric chip...... for long-term online cell culture observation under controlled conditions. The chip incorporated a microfluidic flow equalization system, assuring uniform perfusion of the cell culture media throughout the cell culture chamber. The integrated indium-tin-oxide heater and miniature temperature probe linked....... HeLa cells were cultured for up to 2 weeks within the cell culture chip and monitored using a time-lapse video recording microscopy setup. Cell attachment and spreading was observed during the first 10-20 h (lag phase). After approximately 20 h, cell growth gained exponential character...

  3. Rapid Solidification of Sn-Cu-Al Alloys for High-Reliability, Lead-Free Solder: Part I. Microstructural Characterization of Rapidly Solidified Solders

    Science.gov (United States)

    Reeve, Kathlene N.; Choquette, Stephanie M.; Anderson, Iver E.; Handwerker, Carol A.

    2016-12-01

    Particles of Cu x Al y in Sn-Cu-Al solders have previously been shown to nucleate the Cu6Sn5 phase during solidification. In this study, the number and size of Cu6Sn5 nucleation sites were controlled through the particle size refinement of Cu x Al y via rapid solidification processing and controlled cooling in a differential scanning calorimeter. Cooling rates spanning eight orders of magnitude were used to refine the average Cu x Al y and Cu6Sn5 particle sizes down to submicron ranges. The average particle sizes, particle size distributions, and morphologies in the microstructures were analyzed as a function of alloy composition and cooling rate. Deep etching of the samples revealed the three-dimensional microstructures and illuminated the epitaxial and morphological relationships between the Cu x Al y and Cu6Sn5 phases. Transitions in the Cu6Sn5 particle morphologies from faceted rods to nonfaceted, equiaxed particles were observed as a function of both cooling rate and composition. Initial solidification cooling rates within the range of 103 to 104 °C/s were found to be optimal for realizing particle size refinement and maintaining the Cu x Al y /Cu6Sn5 nucleant relationship. In addition, little evidence of the formation or decomposition of the ternary- β phase in the solidified alloys was noted. Solidification pathways omitting the formation of the ternary- β phase agreed well with observed room temperature microstructures.

  4. Bond markets in Africa

    Directory of Open Access Journals (Sweden)

    Yibin Mu

    2013-07-01

    Full Text Available African bond markets have been steadily growing in recent years, but nonetheless remain undeveloped. African countries would benefit from greater access to financing and deeper financial markets. This paper compiles a unique set of data on government securities and corporate bond markets in Africa. It then applies an econometric model to analyze the key determinants of African government securities market and corporate bond market capitalization. Government securities market capitalization is directly related to better institutions and interest rate volatility, and inversely related to smaller fiscal deficits, higher interest rate spreads, exchange rate volatility, and current and capital account openness. Corporate bond market capitalization is directly linked to economic size, the level of development of the economy and financial markets, better institutions, and interest rate volatility, and inversely related to higher interest rate spreads and current account openness. Policy implications follow.

  5. Handbook of wafer bonding

    CERN Document Server

    Ramm, Peter; Taklo, Maaike M V

    2011-01-01

    Written by an author and editor team from microsystems companies and industry-near research organizations, this handbook and reference presents dependable, first-hand information on bonding technologies.In the first part, researchers from companies and institutions around the world discuss the most reliable and reproducible technologies for the production of bonded wafers. The second part is devoted to current and emerging applications, including microresonators, biosensors and precise measuring devices.

  6. Diffusion bonding techniques

    International Nuclear Information System (INIS)

    Peters, R.D.

    1978-01-01

    The applications of diffusion bonding at the General Electric Neutron Devices Department are briefly discussed, with particular emphasis on the gold/gold or gold/indium joints made between metallized alumina ceramic parts in the vacuum switch tube and the crystal resonator programs. Fixtures which use the differential expansion of dissimilar metals are described and compared to one that uses hydraulic pressure to apply the necessary bonding force

  7. One-step fabrication of microfluidic chips with in-plane, adhesive-free interconnections

    International Nuclear Information System (INIS)

    Sabourin, D; Dufva, M; Jensen, T; Kutter, J; Snakenborg, D

    2010-01-01

    A simple method for creating interconnections to a common microfluidic device material, poly(methyl methacrylate) (PMMA), is presented. A press-fit interconnection is created between oversized, deformable tubing and complementary, undersized semi-circular ports fabricated into PMMA bonding surfaces by direct micromilling. Upon UV-assisted bonding the tubing is trapped in the ports of the PMMA chip and forms an integrated, in-plane and adhesive-free interconnection. The interconnections support the average pressure of 6.1 bar and can be made with small dead volumes. A comparison is made to a similar interconnection approach which uses tubing to act as a gasket between a needle and port on the microfluidic chip. (technical note)

  8. Measurement of erosion of stainless steel by molten lead-free solder using micro-focus x-ray CT system

    International Nuclear Information System (INIS)

    Nishikawa, Hiroshi; Takemoto, Tadashi; Kang, Songai

    2009-01-01

    The severe erosion damage, which is caused by a molten lead-free solder, of wave solder equipment made into stainless steel has been encountered in operation. Then, the higher maintenance frequency and reduced life time of wave solder machine component is a serious issue in a manufacturing process. In this study, the evaluation method of erosion of stainless steel by molten lead-free solders was investigated using micro-focus X-ray systems for fluoroscopic and computed tomography (CT). As a result, it was found that the fluoroscopic image could truly reconstruct the cross-shape of the stainless steel sample after immersion test without destruction. In the case of X-ray systems for fluoroscopic and CT used in this study, three-dimensional data can be obtained. Therefore, it was possible to easily check the whole picture of the test sample after immersion test and to decide the maximum erosion depth of test sample. (author)

  9. Study on Mitigation Method of Solder Corrosion for Crystalline Silicon Photovoltaic Modules

    Directory of Open Access Journals (Sweden)

    Ju-Hee Kim

    2014-01-01

    Full Text Available The corrosion of 62Sn36Pb2Ag solder connections poses serious difficulties for outdoor-exposed photovoltaic (PV modules, as connection degradation contributes to the increase in series resistance (RS of PV modules. In this study, we investigated a corrosion mitigation method based on the corrosion mechanism. The effect of added sacrificial metal on the reliability of PV modules was evaluated using the oxidation-reduction (redox reaction under damp heat (DH conditions. Experimental results after exposure to DH show that the main reason for the decrease in power was a drop in the module’s fill factor. This drop was attributed to the increase of RS. The drop in output power of the PV module without added sacrificial metal is greater than that of the sample with sacrificial metal. Electroluminescence and current-voltage mapping analysis also show that the PV module with sacrificial metal experienced less degradation than the sample without sacrificial metal.

  10. Thermal Analysis of the Sn-Ag-Cu-In Solder Alloy

    DEFF Research Database (Denmark)

    Sopousek, J.; Palcut, Marián; Hodúlová, Erika

    2010-01-01

    The tin-based alloy Sn-1.5Ag-0.7Cu-9.5In (composition in wt.%) is a potential candidate for lead-free soldering at temperatures close to 200°C due to the significant amount of indium. Samples of Sn-1.5Ag-0.7Cu-9.5In were prepared by controlled melting of the pure elements, followed by quenching...... to room temperature. The samples were analyzed by scanning electron microscopy/energy-dispersive x-ray spectroscopy (SEM/EDS) and electron backscatter diffraction. The solidified melt consisted of four different phases. Solidification behavior was monitored by heat-flux differential scanning calorimetry...

  11. Determination of Te in soldering tin using continuous flowing electrochemical hydride generation atomic fluorescence spectrometry

    International Nuclear Information System (INIS)

    Jiang Xianjuan; Gan Wuer; Han Suping; He Youzhao

    2008-01-01

    An electrochemical hydride generation system was developed for the detection of Te by coupling an electrochemical hydride generator with atomic fluorescence spectrometry. Since TeH 2 is unstable and easily decomposes in solution, a reticular W filament cathode was used in the present system. The TeH 2 generated on the cathode surface was effectively driven out by sweeping gas from the cathode chamber. In addition, a low temperature electrochemical cell (10 deg. C) was applied to reduce the decomposition of TeH 2 in solution. The limit of detection (LOD) was 2.2 ng ml -1 and the relative standard deviation (RSD) was 3.9% for nine consecutive measurements of standard solution. This method was successfully employed for determination of Te in soldering tin material

  12. Beta-Tin Grain Formation in Aluminum-Modified Lead-Free Solder Alloys

    Science.gov (United States)

    Reeve, Kathlene N.; Handwerker, Carol A.

    2018-01-01

    The limited number of independent β-Sn grain orientations that typically form during solidification of Sn-based solders and the resulting large β-Sn grain size have major effects on overall solder performance and reliability. This study analyzes whether additions of Al to Sn-Cu and Sn-Cu-Ag alloys can be used to change the grain size, morphology, and twinning structures of atomized (as-solidified) and re-melted (reflowed) β-Sn dendrites as determined using scanning electron microscopy and electron backscatter diffraction for as-solidified and reflow cycled (20-250°C, 1-5 cycles) Sn-Cu-Al and Sn-Ag-Cu-Al drip atomized spheres (260 μm diameter). The resulting microstructures were compared to as-solidified and reflow cycled Sn-Ag-Cu spheres (450 μm diameter) as well as as-solidified Sn-Ag-Cu, Sn-Cu, and Sn-Ag microstructures from the literature. Previous literature observations reporting reductions in undercooling and β-Sn grain size with Al micro-alloying additions could not be correlated to the presence of the Cu9Al4 phase or Al solute. The as-solidified spheres displayed no change in β-Sn dendrite structure or grain size when compared to non-Al-modified alloys, and the reflow cycled spheres produced high undercoolings (22-64°C), indicating a lack of potent nucleation sites. The current findings highlighted the role of Ag in the formation of the interlaced twinning structure and demonstrated that with deliberate compositional choices, formation of the alloy's β-Sn grain structure (cyclical twinning versus interlaced twinning) could be influenced, in both the as-solidified and reflow cycled states, though still not producing the fine-grain sizes and multiple orientations desired for improved thermomechanical properties.

  13. Effects of aging time on the mechanical properties of Sn–9Zn–1.5Ag–xBi lead-free solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chih-Yao [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Hon, Min-Hsiung [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Kaohsiung 80782, Taiwan (China); Wang, Moo-Chin, E-mail: mcwang@kmu.edu.tw [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100, Shih-Chuan 1st Road, Kaohsiung 80728, Taiwan (China); Chen, Ying-Ru; Chang, Kuo-Ming; Li, Wang-Long [Institute of Nanotechnology and Microsystems Engineering, National Cheng Kung University, No. 1, University Road, Tainan 70101, Taiwan (China)

    2014-01-05

    Highlights: • The microstructure of these solder alloys are composed of Sn-rich phase and Ag{sub 3}Sn. • The grain size of Sn–9Zn–1.5Ag–xBi solder alloys increases with rose aging time. • The maximum yield strength is 112.7 ± 2.2 MPa for Sn–9Zn–1.5Ag–3Bi solder alloys. • TEM observed that Bi appears as oblong shape fine particles. -- Abstract: The effects of aging time on the mechanical properties of the Sn–9Zn–1.5Ag–xBi lead-free solder alloys are investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive spectrometry (EDS) and a universal testing machine. The experimental results show that the microstructure of Sn–9Zn–1.5Ag–xBi solder alloys is composed of Sn-rich phase and AgZn{sub 3}. No other intermetallic compounds (IMCs) with Bi content was observed in the solder matrix for Sn–9Zn–1.5Ag solder alloys with various Bi contents before and after aging at 150 °C for different durations. The lattice parameter increases significantly with increasing aging time or Bi addition. The size of Sn-rich grain increased gradually with aging time increased, but decreases with Bi content increases. The maximum yield strength is 112.7 ± 2.2 MPa for Sn–9Zn–1.5Ag–3Bi solder alloy before aging.

  14. Effects of aging time on the mechanical properties of Sn–9Zn–1.5Ag–xBi lead-free solder alloys

    International Nuclear Information System (INIS)

    Liu, Chih-Yao; Hon, Min-Hsiung; Wang, Moo-Chin; Chen, Ying-Ru; Chang, Kuo-Ming; Li, Wang-Long

    2014-01-01

    Highlights: • The microstructure of these solder alloys are composed of Sn-rich phase and Ag 3 Sn. • The grain size of Sn–9Zn–1.5Ag–xBi solder alloys increases with rose aging time. • The maximum yield strength is 112.7 ± 2.2 MPa for Sn–9Zn–1.5Ag–3Bi solder alloys. • TEM observed that Bi appears as oblong shape fine particles. -- Abstract: The effects of aging time on the mechanical properties of the Sn–9Zn–1.5Ag–xBi lead-free solder alloys are investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive spectrometry (EDS) and a universal testing machine. The experimental results show that the microstructure of Sn–9Zn–1.5Ag–xBi solder alloys is composed of Sn-rich phase and AgZn 3 . No other intermetallic compounds (IMCs) with Bi content was observed in the solder matrix for Sn–9Zn–1.5Ag solder alloys with various Bi contents before and after aging at 150 °C for different durations. The lattice parameter increases significantly with increasing aging time or Bi addition. The size of Sn-rich grain increased gradually with aging time increased, but decreases with Bi content increases. The maximum yield strength is 112.7 ± 2.2 MPa for Sn–9Zn–1.5Ag–3Bi solder alloy before aging

  15. Effects of metallic nanoparticle doped flux on the interfacial intermetallic compounds between lead-free solder ball and copper substrate

    International Nuclear Information System (INIS)

    Sujan, G.K.; Haseeb, A.S.M.A.; Afifi, A.B.M.

    2014-01-01

    Lead free solders currently in use are prone to develop thick interfacial intermetallic compound layers with rough morphology which are detrimental to the long term solder joint reliability. A novel method has been developed to control the morphology and growth of intermetallic compound layers between lead-free Sn–3.0Ag–0.5Cu solder ball and copper substrate by doping a water soluble flux with metallic nanoparticles. Four types of metallic nanoparticles (nickel, cobalt, molybdenum and titanium) were used to investigate their effects on the wetting behavior and interfacial microstructural evaluations after reflow. Nanoparticles were dispersed manually with a water soluble flux and the resulting nanoparticle doped flux was placed on copper substrate. Lead-free Sn–3.0Ag–0.5Cu solder balls of diameter 0.45 mm were placed on top of the flux and were reflowed at a peak temperature of 240 °C for 45 s. Angle of contact, wetting area and interfacial microstructure were studied by optical microscopy, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. It was observed that the angle of contact increased and wetting area decreased with the addition of cobalt, molybdenum and titanium nanoparticles to flux. On the other hand, wettability improved with the addition of nickel nanoparticles. Cross-sectional micrographs revealed that both nickel and cobalt nanoparticle doping transformed the morphology of Cu 6 Sn 5 from a typical scallop type to a planer one and reduced the intermetallic compound thickness under optimum condition. These effects were suggested to be related to in-situ interfacial alloying at the interface during reflow. The minimum amount of nanoparticles required to produce the planer morphology was found to be 0.1 wt.% for both nickel and cobalt. Molybdenum and titanium nanoparticles neither appear to undergo alloying during reflow nor have any influence at the solder/substrate interfacial reaction. Thus, doping of flux

  16. Effects of metallic nanoparticle doped flux on the interfacial intermetallic compounds between lead-free solder ball and copper substrate

    Energy Technology Data Exchange (ETDEWEB)

    Sujan, G.K., E-mail: sgkumer@gmail.com; Haseeb, A.S.M.A., E-mail: haseeb@um.edu.my; Afifi, A.B.M., E-mail: amalina@um.edu.my

    2014-11-15

    Lead free solders currently in use are prone to develop thick interfacial intermetallic compound layers with rough morphology which are detrimental to the long term solder joint reliability. A novel method has been developed to control the morphology and growth of intermetallic compound layers between lead-free Sn–3.0Ag–0.5Cu solder ball and copper substrate by doping a water soluble flux with metallic nanoparticles. Four types of metallic nanoparticles (nickel, cobalt, molybdenum and titanium) were used to investigate their effects on the wetting behavior and interfacial microstructural evaluations after reflow. Nanoparticles were dispersed manually with a water soluble flux and the resulting nanoparticle doped flux was placed on copper substrate. Lead-free Sn–3.0Ag–0.5Cu solder balls of diameter 0.45 mm were placed on top of the flux and were reflowed at a peak temperature of 240 °C for 45 s. Angle of contact, wetting area and interfacial microstructure were studied by optical microscopy, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. It was observed that the angle of contact increased and wetting area decreased with the addition of cobalt, molybdenum and titanium nanoparticles to flux. On the other hand, wettability improved with the addition of nickel nanoparticles. Cross-sectional micrographs revealed that both nickel and cobalt nanoparticle doping transformed the morphology of Cu{sub 6}Sn{sub 5} from a typical scallop type to a planer one and reduced the intermetallic compound thickness under optimum condition. These effects were suggested to be related to in-situ interfacial alloying at the interface during reflow. The minimum amount of nanoparticles required to produce the planer morphology was found to be 0.1 wt.% for both nickel and cobalt. Molybdenum and titanium nanoparticles neither appear to undergo alloying during reflow nor have any influence at the solder/substrate interfacial reaction. Thus, doping

  17. Mechanistic Prediction of the Effect of Microstructural Coarsening on Creep Response of SnAgCu Solder Joints

    Science.gov (United States)

    Mukherjee, S.; Chauhan, P.; Osterman, M.; Dasgupta, A.; Pecht, M.

    2016-07-01

    Mechanistic microstructural models have been developed to capture the effect of isothermal aging on time dependent viscoplastic response of Sn3.0Ag0.5Cu (SAC305) solders. SnAgCu (SAC) solders undergo continuous microstructural coarsening during both storage and service because of their high homologous temperature. The microstructures of these low melting point alloys continuously evolve during service. This results in evolution of creep properties of the joint over time, thereby influencing the long term reliability of microelectronic packages. It is well documented that isothermal aging degrades the creep resistance of SAC solder. SAC305 alloy is aged for (24-1000) h at (25-100)°C (~0.6-0.8 × T melt). Cross-sectioning and image processing techniques were used to periodically quantify the effect of isothermal aging on phase coarsening and evolution. The parameters monitored during isothermal aging include size, area fraction, and inter-particle spacing of nanoscale Ag3Sn intermetallic compounds (IMCs) and the volume fraction of micronscale Cu6Sn5 IMCs, as well as the area fraction of pure tin dendrites. Effects of microstructural evolution on secondary creep constitutive response of SAC305 solder joints were then modeled using a mechanistic multiscale creep model. The mechanistic phenomena modeled include: (1) dispersion strengthening by coarsened nanoscale Ag3Sn IMCs in the eutectic phase; and (2) load sharing between pro-eutectic Sn dendrites and the surrounding coarsened eutectic Sn-Ag phase and microscale Cu6Sn5 IMCs. The coarse-grained polycrystalline Sn microstructure in SAC305 solder was not captured in the above model because isothermal aging does not cause any significant change in the initial grain size and orientation of SAC305 solder joints. The above mechanistic model can successfully capture the drop in creep resistance due to the influence of isothermal aging on SAC305 single crystals. Contribution of grain boundary sliding to the creep strain of

  18. Fabrication of 3D Microfluidic Devices by Thermal Bonding of Thin Poly(methyl methacrylate) Films

    KAUST Repository

    Perez, Paul

    2012-07-01

    The use of thin-film techniques for the fabrication of microfluidic devices has gained attention over the last decade, particularly for three-dimensional channel structures. The reasons for this include effective use of chip volume, mechanical flexibility, dead volume reduction, enhanced design capabilities, integration of passive elements, and scalability. Several fabrication techniques have been adapted for use on thin films: laser ablation and hot embossing are popular for channel fabrication, and lamination is widely used for channel enclosure. However, none of the previous studies have been able to achieve a strong bond that is reliable under moderate positive pressures. The present work aims to develop a thin-film process that provides design versatility, speed, channel profile homogeneity, and the reliability that others fail to achieve. The three building blocks of the proposed baseline were fifty-micron poly(methyl methacrylate) thin films as substrates, channel patterning by laser ablation, and device assembly by thermal-fusion bonding. Channel fabrication was characterized and tuned to produce the desired dimensions and surface roughness. Thermal bonding was performed using an adapted mechanical testing device and optimized to produce the maximum bonding strength without significant channel deformation. Bonding multilayered devices, incorporating conduction lines, and integrating various types of membranes as passive elements demonstrated the versatility of the process. Finally, this baseline was used to fabricate a droplet generator and a DNA detection chip based on micro-bead agglomeration. It was found that a combination of low laser power and scanning speed produced channel surfaces with better uniformity than those obtained with higher values. In addition, the implemented bonding technique provided the process with the most reliable bond strength reported, so far, for thin-film microfluidics. Overall, the present work proved to be versatile

  19. Massive spalling of Cu-Zn and Cu-Al intermetallic compounds at the interface between solders and Cu substrate during liquid state reaction

    Science.gov (United States)

    Kotadia, H. R.; Panneerselvam, A.; Mokhtari, O.; Green, M. A.; Mannan, S. H.

    2012-04-01

    The interfacial intermetallic compound (IMC) formation between Cu substrate and Sn-3.8Ag-0.7Cu-X (wt.%) solder alloys has been studied, where X consists of 0-5% Zn or 0-2% Al. The study has focused on the effect of solder volume as well as the Zn or Al concentration. With low solder volume, when the Zn and Al concentrations in the solder are also low, the initial Cu-Zn and Al-Cu IMC layers, which form at the solder/substrate interface, are not stable and spall off, displaced by a Cu6Sn5 IMC layer. As the total Zn or Al content in the system increases by increasing solder volume, stable CuZn or Al2Cu IMCs form on the substrate and are not displaced. Increasing concentration of Zn has a similar effect of stabilizing the Cu-Zn IMC layer and also of forming a stable Cu5Zn8 layer, but increasing Al concentration alone does not prevent spalling of Al2Cu. These results are explained using a combination of thermodynamic- and kinetics-based arguments.

  20. Micro flow-through PCR in a PMMA chip fabricated by KrF excimer laser.

    Science.gov (United States)

    Yao, Liying; Liu, Baoan; Chen, Tao; Liu, Shibing; Zuo, Tiechuan

    2005-09-01

    As the third PCR technology, micro flow-through PCR chip can amplify DNA specifically in an exponential fashion in vitro. Nowadays many academies in the world have successfully amplified DNA using their own-made flow-through PCR chip. In this paper, the ablation principle of PMMA at 248 nm excimer laser was studied, then a PMMA based flow-through PCR chip with 20 cycles was fabricated by excimer laser at 19 kv and 18 mm/min. The chip was bonded together with another cover chip at 105( composite function)C, 160 N and 20 minutes. In the end, it was integrated with electrical thermal thin films and Pt 100 temperature sensors. The temperature controllers was built standard PID digital temperature controller, the temperature control precision was +/- 0.2( composite function)C. The temperature grads between the three temperature zones were 16.5 and 22.2( composite function)C respectively, the gaps between the temperature zones could realize heat insulation.

  1. Romanian government bond market

    Directory of Open Access Journals (Sweden)

    Cornelia POP

    2012-12-01

    Full Text Available The present paper aims to present the level of development reached by Romanian government bond market segment, as part of the country financial market. The analysis will be descriptive (the data series available for Romania are short, based on the secondary data offered by the official bodies involved in the process of issuing and trading the Romanian government bonds (Romanian Ministry of Public Finance, Romanian National Bank and Bucharest Stock Exchange, and also on secondary data provided by the Federation of European Stock Exchanges.To enhance the market credibility as a benchmark, a various combination of measures is necessary; among these measures are mentioned: the extension of the yield curve; the issuance calendars in order to improve transparency; increasing the disclosure of information on public debt issuance and statistics; holding regular meetings with dealers, institutional investors and rating agencies; introducing a system of primary dealers; establishing a repurchase (repo market in the government bond market. These measures will be discussed based on the evolution presented inside the paper.The paper conclude with the fact that, until now, the Romanian government bond market did not provide a benchmark for the domestic financial market and that further efforts are needed in order to increase the government bond market transparency and liquidity.

  2. Interstellar hydrogen bonding

    Science.gov (United States)

    Etim, Emmanuel E.; Gorai, Prasanta; Das, Ankan; Chakrabarti, Sandip K.; Arunan, Elangannan

    2018-06-01

    This paper reports the first extensive study of the existence and effects of interstellar hydrogen bonding. The reactions that occur on the surface of the interstellar dust grains are the dominant processes by which interstellar molecules are formed. Water molecules constitute about 70% of the interstellar ice. These water molecules serve as the platform for hydrogen bonding. High level quantum chemical simulations for the hydrogen bond interaction between 20 interstellar molecules (known and possible) and water are carried out using different ab-intio methods. It is evident that if the formation of these species is mainly governed by the ice phase reactions, there is a direct correlation between the binding energies of these complexes and the gas phase abundances of these interstellar molecules. Interstellar hydrogen bonding may cause lower gas abundance of the complex organic molecules (COMs) at the low temperature. From these results, ketenes whose less stable isomers that are more strongly bonded to the surface of the interstellar dust grains have been observed are proposed as suitable candidates for astronomical observations.

  3. Study of a Microfluidic Chip Integrating Single Cell Trap and 3D Stable Rotation Manipulation

    Directory of Open Access Journals (Sweden)

    Liang Huang

    2016-08-01

    Full Text Available Single cell manipulation technology has been widely applied in biological fields, such as cell injection/enucleation, cell physiological measurement, and cell imaging. Recently, a biochip platform with a novel configuration of electrodes for cell 3D rotation has been successfully developed by generating rotating electric fields. However, the rotation platform still has two major shortcomings that need to be improved. The primary problem is that there is no on-chip module to facilitate the placement of a single cell into the rotation chamber, which causes very low efficiency in experiment to manually pipette single 10-micron-scale cells into rotation position. Secondly, the cell in the chamber may suffer from unstable rotation, which includes gravity-induced sinking down to the chamber bottom or electric-force-induced on-plane movement. To solve the two problems, in this paper we propose a new microfluidic chip with manipulation capabilities of single cell trap and single cell 3D stable rotation, both on one chip. The new microfluidic chip consists of two parts. The top capture part is based on the least flow resistance principle and is used to capture a single cell and to transport it to the rotation chamber. The bottom rotation part is based on dielectrophoresis (DEP and is used to 3D rotate the single cell in the rotation chamber with enhanced stability. The two parts are aligned and bonded together to form closed channels for microfluidic handling. Using COMSOL simulation and preliminary experiments, we have verified, in principle, the concept of on-chip single cell traps and 3D stable rotation, and identified key parameters for chip structures, microfluidic handling, and electrode configurations. The work has laid a solid foundation for on-going chip fabrication and experiment validation.

  4. Safe and Liquid Mortgage Bonds

    DEFF Research Database (Denmark)

    Dick-Nielsen, Jens; Gyntelberg, Jacob; Lund, Jesper

    This paper shows that strict match pass-through funding of covered bonds provides safe and liquid mortgage bonds. Despite a 30% drop in house prices during the 2008 global crisis Danish mortgage bonds remained as liquid as most European government bonds. The Danish pass-through system effectively...... eliminates credit risk from the investor's perspective. Similar to other safe bonds, funding liquidity becomes the main driver of mortgage bond liquidity and this creates commonality in liquidity across markets and countries. These findings have implications for how to design a robust mortgage bond system...

  5. Experiment list: SRX122465 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available 6 || chip antibody=Relb || treatment=LPS || time=120 min || chip antibody manufacturer 1=Bethyl || chip anti...body catalog number 1=A302-183A || chip antibody manufacturer 2=Santa Cruz || chip antibody catalog number 2

  6. Experiment list: SRX122555 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available chip antibody=Stat1 || treatment=LPS || time=120 min || chip antibody manufacturer 1=Santa Cruz || chip anti...body catalog number 1=sc-346 || chip antibody manufacturer 2=Bethyl || chip antibody catalog number 2=A302-7

  7. A method for UV-bonding in the fabrication of glass electrophoretic microchips.

    Science.gov (United States)

    Huang, Z; Sanders, J C; Dunsmor, C; Ahmadzadeh, H; Landers, J P

    2001-10-01

    This paper presents an approach for the development of methodologies amenable to simple and inexpensive microchip fabrication, potentially applicable to dissimilar materials bonding and chip integration. The method involves a UV-curable glue that can be used for glass microchip fabrication bonding at room temperature. This involves nothing more than fabrication of glue "guide channels" into the microchip architecture that upon exposure to the appropriate UV light source, bonds the etched plate and cover plate together. The microchip performance was verified by capillary zone electrophoresis (CZE) of small fluorescent molecules with no microchannel surface modification carried out, as well as with a DNA fragment separation following surface modification. The performance of these UV-bonded electrophoretic microchips indicates that this method may provide an alternative to high temperature bonding.

  8. Hydrogen bonded supramolecular materials

    CERN Document Server

    Li, Zhan-Ting

    2015-01-01

    This book is an up-to-date text covering topics in utilizing hydrogen bonding for constructing functional architectures and supramolecular materials. The first chapter addresses the control of photo-induced electron and energy transfer. The second chapter summarizes the formation of nano-porous materials. The following two chapters introduce self-assembled gels, many of which exhibit unique functions. Other chapters cover the advances in supramolecular liquid crystals and the versatility of hydrogen bonding in tuning/improving the properties and performance of materials. This book is designed

  9. Continuing bonds and place.

    Science.gov (United States)

    Jonsson, Annika; Walter, Tony

    2017-08-01

    Where do people feel closest to those they have lost? This article explores how continuing bonds with a deceased person can be rooted in a particular place or places. Some conceptual resources are sketched, namely continuing bonds, place attachment, ancestral places, home, reminder theory, and loss of place. The authors use these concepts to analyze interview material with seven Swedes and five Britons who often thought warmly of the deceased as residing in a particular place and often performing characteristic actions. The destruction of such a place, by contrast, could create a troubling, haunting absence, complicating the deceased's absent-presence.

  10. Aging effects on the microstructure, surface characteristics and wettability of Cu pretinned with Sn-Pb solders

    Energy Technology Data Exchange (ETDEWEB)

    Linch, Heidi Sue [Univ. of California, Berkeley, CA (United States)

    1993-11-01

    This study investigates effects of aging in air and argon at 170 C on Cu coupons which were pretinned with 75Sn-25Pb, 8Sn-92Pb, and 5Sn-95Pb solders. Coatings were applied using electroplating or hot dipping techniques. The coating thickness was controlled between 3 to 3μm and the specimens were aged for 0 hours, 2 hours, 24 hours and 2 weeks. Wetting balance tests were used to evaluate the wettability of the test specimens. Microstructural development was evaluated using X-ray diffraction, energy dispersive X-ray and Auger spectroscopy, as well as optical and scanning electron microscopy. The wetting behavior of the test specimens is interpreted with respect to observed microstructural changes and as a function of aging time, solder composition, and processing conditions.

  11. Aging effects on fracture behavior of 63Sn37Pb eutectic solder during tensile tests under the SEM

    International Nuclear Information System (INIS)

    Ding Ying; Wang Chunqing; Li Mingyu; Bang Hansur

    2004-01-01

    This study investigates the influence of aging treatment on fracture behavior of Sn-Pb eutectic solder alloys at different loading rate regime during tensile tests under the scanning electron microscope. In high homologous temperature, the solder exhibit the creep behavior that could be confirmed through the phenomena of grain boundary sliding (GBS) to both as-cast and aged specimens. Owing to the large grain scale after high temperature storage, boundary behavior was limited to some extent for the difficulty in grain rotation and boundary migration. Instead, drastic intragranular deformation occurred. Also, the phase coarsening weakened the combination between lead-rich phase and tin matrix. Consequently, surface fragmentation was detected for the aged specimens. Furthermore, the fracture mechanism changed from intergranular dominated to transgranular dominated with increasing loading rate to both specimens during early stage

  12. Photonic network-on-chip design

    CERN Document Server

    Bergman, Keren; Biberman, Aleksandr; Chan, Johnnie; Hendry, Gilbert

    2013-01-01

    This book provides a comprehensive synthesis of the theory and practice of photonic devices for networks-on-chip. It outlines the issues in designing photonic network-on-chip architectures for future many-core high performance chip multiprocessors. The discussion is built from the bottom up: starting with the design and implementation of key photonic devices and building blocks, reviewing networking and network-on-chip theory and existing research, and finishing with describing various architectures, their characteristics, and the impact they will have on a computing system. After acquainting

  13. Influence of intermetallic growth on the mechanical properties of Zn–Sn–Cu–Bi/Cu solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Fei; Yao, Jia; Liang, Jingwei; Qiu, Xiaoming, E-mail: qiuxm13@163.com

    2015-11-15

    The formation of intermetallic reaction layers and their influence on shear strength and fractography was investigated between the Zn–Sn–Cu–Bi (ZSCB) and Cu substrate during the liquid state reaction at 450 °C after 10–90 s. Results showed that reliable solder joints could be obtained at 450 °C after 15–30 s of wetting, accompanied by the creation of scallop ε-CuZn{sub 5}, flat γ-Cu{sub 5}Zn{sub 8} and β-CuZn intermetallic layers in ZSCB/Cu interface. However, with excess increase of soldering time, a transient intermetallic ε-CuZn{sub 4} phase was nuclear and grew at ε-CuZn{sub 5}/γ-Cu{sub 5}Zn{sub 8} interface, which apparently deteriorated the shear strength of solder joints from 76.5 MPa to 51.6 MPa. The sensitivity of the fracture proportion was gradually transformed from monotonic ε-CuZn{sub 5} to the mixture of ε-CuZn{sub 4} and ε-CuZn{sub 5} intermetallic cleavage. Furthermore, the growth mechanism of ε-CuZn{sub 4} intermetallic phase at the ZSCB/Cu interface was discussed. - Highlights: • There are four interfacial intermetallic layers formed at the Zn–Sn–Cu–Bi/Cu interface. • The growth mechanism of ε-CuZn{sub 4} intermetallic phase was discussed. • The wetting time of Zn–Sn–Cu–Bi solder in contact with Cu substrate is a key parameter.

  14. Behavior of Sn-0.7Cu-xZn lead free solder on physical properties and micro structure

    Science.gov (United States)

    Siahaan, Erwin

    2017-09-01

    The issues to substitute Tin-Lead Solders is concerning the health and environmental hazards that is caused by lead, and also legislative actions around the world regarding lead toxicity, which has prompted the research community to attempt to replace solder alloys for the traditional Sn-Pb alloys lead which has been used by industrial worker throughout history because it is easily extracted and refined at a relatively low energy cost and also has a range of useful properties. Traditional industry lead has been used in soldering materials for electronic applications because it has low melting point and a soft, malleable nature, when combined with tin at the eutectic composition which causes the alloy to flow easily in the liquid state and solidifies over a very small range of temperature. One of the potential candidate to replace tin-lead solder is Sn-Cu-Zn eutectic alloy as it has a lower melting temperature. Consequently, it is of interest to determine what reactions can occur in ternary systems derived from the Sn-Cu-Zn eutectic. One such system is Sn-0.7Cu-xZn. The specimen was elaborated on physical properties. The chemical content was analyzed by using Shimadzu XRD and melting point was analyzed by using Differential Scanning Calorimeter ( DSC ). The results has shown that the highest addition of Zinc content (15%Zn) will decrease the melting temperatur to 189°C compared to Sn-Pb at 183°C Increasing the amount of Zn on Sn0.7Cu-xZn alloys will decrease Cu3Sn intermetallic coumpound.

  15. A scalable single-chip multi-processor architecture with on-chip RTOS kernel

    NARCIS (Netherlands)

    Theelen, B.D.; Verschueren, A.C.; Reyes Suarez, V.V.; Stevens, M.P.J.; Nunez, A.

    2003-01-01

    Now that system-on-chip technology is emerging, single-chip multi-processors are becoming feasible. A key problem of designing such systems is the complexity of their on-chip interconnects and memory architecture. It is furthermore unclear at what level software should be integrated. An example of a

  16. Electromigration-induced cracks in Cu/Sn3.5Ag/Cu solder reaction couple at room temperature

    International Nuclear Information System (INIS)

    He Hongwen; Xu Guangchen; Guo Fu

    2009-01-01

    Electromigration (EM) behavior of Cu/Sn 3.5 Ag/Cu solder reaction couple was investigated with a high current density of 5 x 10 3 A/cm 2 at room temperature. One dimensional structure, copper wire/solder ball/copper wire SRC was designed and fabricated to dissipate the Joule heating induced by the current flow. In addition, thermomigration effect was excluded due to the symmetrical structure of the SRC. The experimental results indicated that micro-cracks initially appeared near the cathode interface between solder matrix and copper substrate after 474 h current stressing. With current stressing time increased, the cracks propagated and extended along the cathode interface. It should be noted that the continuous Cu 6 Sn 5 intermetallic compounds (IMCs) layer both at the anode and at the cathode remained their sizes. Interestingly, tiny cracks appeared at the root of some long column-type Cu 6 Sn 5 at the cathode interface due to the thermal stress.

  17. Sutureless liver repair and hemorrhage control using laser-mediated fusion of human albumin as a solder.

    Science.gov (United States)

    Wadia, Y; Xie, H; Kajitani, M

    2001-07-01

    Major liver trauma has a high mortality because of immediate exsanguination and a delayed morbidity from septicemia, peritonitis, biliary fistulae, and delayed secondary hemorrhage. We evaluated laser soldering using liquid albumin for welding liver injuries. Fourteen lacerations (6 x 2 cm) and 13 nonanatomic resection injuries (raw surface, 8 x 2 cm) were repaired. An 805-nm laser was used to weld 53% liquid albumin-indocyanine green solder to the liver surface, reinforcing it by welding a free autologous omental scaffold. The animals were heparinized and hepatic inflow occlusion was used for vascular control. For both laceration and resection injuries, 16 soldering repairs were evaluated acutely at 3 hours. Eleven animals were evaluated chronically, two at 2 weeks and nine at 4 weeks. All 27 laser mediated-liver repairs had minimal blood loss compared with the suture controls. No dehiscence, hemorrhage, or bile leakage was seen in any of the laser repairs after 3 hours. All 11 chronic repairs healed without complication. This modality effectively seals the liver surface, joins lacerations with minimal thermal injury, and works independently of the patient's coagulation status.

  18. The micro-droplet behavior of a molten lead-free solder in an inkjet printing process

    International Nuclear Information System (INIS)

    Tsai, M H; Chou, H H; Hwang, W S

    2009-01-01

    An experimental investigation on the droplet formation of molten Sn3.0 wt%Ag0.5 wt%Cu alloy by an inkjet printing process was conducted. The printing process used a piezoelectric print head with a nozzle orifice diameter of 50 µm. Micro-droplets of a molten lead-free solder were ejected at 230 °C. The print head was driven by a bipolar pulse 40 V in amplitude. The major variables for this study were two pulse times; t rise /t finalrise and t fall , as well as N 2 back-pressure in the molten solder reservoir. Under various printing conditions, extrusion of the liquid column, contraction of liquid thread and pinch-off of liquid thread at nozzle exit were observed by monitoring the dynamics of the molten solder droplet ejection process. The droplet formation was found to be insensitive to t rise and t finalrise in the range of 250–1000 µs. The behavior of droplet formation was, however, significantly affected by the transfer rate, t fall , in the range of 30–60 µs and t fall of 50 µs yielded the most desirable condition of single droplet formation. The N 2 back-pressure was also found to be critical, where a back pressure between 10 and 21 kPa could give the desirable single-droplet formation condition

  19. New Coating Technique of Ceramic Implants with Different Glass Solder Matrices for Improved Osseointegration-Mechanical Investigations.

    Science.gov (United States)

    Mick, Enrico; Markhoff, Jana; Mitrovic, Aurica; Jonitz, Anika; Bader, Rainer

    2013-09-11

    Ceramics are a very popular material in dental implant technology due to their tribological properties, their biocompatibility and their esthetic appearance. However, their natural surface structure lacks the ability of proper osseointegration, which constitutes a crucial process for the stability and, thus, the functionality of a bone implant. We investigated the application of a glass solder matrix in three configurations-consisting mainly of SiO₂, Al₂O₃, K₂O and Na₂O to TZP-A ceramic specimens. The corresponding adhesive strength and surface roughness of the coatings on ceramic specimens have been analyzed. Thereby, high adhesive strength (70.3 ± 7.9 MPa) was found for the three different coatings. The obtained roughness (R z ) amounted to 18.24 ± 2.48 µm in average, with significant differences between the glass solder configurations. Furthermore, one configuration was also tested after additional etching which did not lead to significant increase of surface roughness (19.37 ± 1.04 µm) or adhesive strength (57.2 ± 5.8 MPa). In conclusion, coating with glass solder matrix seems to be a promising surface modification technique that may enable direct insertion of ceramic implants in dental and orthopaedic surgery.

  20. New Coating Technique of Ceramic Implants with Different Glass Solder Matrices for Improved Osseointegration-Mechanical Investigations

    Directory of Open Access Journals (Sweden)

    Rainer Bader

    2013-09-01

    Full Text Available Ceramics are a very popular material in dental implant technology due to their tribological properties, their biocompatibility and their esthetic appearance. However, their natural surface structure lacks the ability of proper osseointegration, which constitutes a crucial process for the stability and, thus, the functionality of a bone implant. We investigated the application of a glass solder matrix in three configurations—consisting mainly of SiO2, Al2O3, K2O and Na2O to TZP-A ceramic specimens. The corresponding adhesive strength and surface roughness of the coatings on ceramic specimens have been analyzed. Thereby, high adhesive strength (70.3 ± 7.9 MPa was found for the three different coatings. The obtained roughness (Rz amounted to 18.24 ± 2.48 µm in average, with significant differences between the glass solder configurations. Furthermore, one configuration was also tested after additional etching which did not lead to significant increase of surface roughness (19.37 ± 1.04 µm or adhesive strength (57.2 ± 5.8 MPa. In conclusion, coating with glass solder matrix seems to be a promising surface modification technique that may enable direct insertion of ceramic implants in dental and orthopaedic surgery.