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Sample records for technology smt soldering

  1. 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 Self-contained, comprehensive, and down-to-earth, it cuts through jargon, peels away outdated notions, and presents all the information needed to select, install, and operate machine soldering equipment.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...

  2. Study on Solder Joint Reliability of Plastic Ball Grid Array Component Based on SMT Products Virtual Assembly Technology

    Institute of Scientific and Technical Information of China (English)

    HUANG Chunyue; WU Zhaohua; ZHOU Dejian

    2006-01-01

    Based on surface mount products virtual assembly technology, the solder joint reliability of plastic ball grid array (PBGA) was studied. Four process parameters, including the upper pad diameter,the stencil thickness, the chip weight on a single solder joint and the lower pad diameter were chose as four control factors. By using an L25(56) orthogonal array the PBGA solder joints which have 25 different process parameters' levels combinations were designed. The numerical models of all the 25 PBGA solder joints were developed and the finite element analysis models were setup. The stress and strain distribution within the PBGA solder joints under thermal cycles were studied by finite element analysis, and the thermal fatigue life of PBGA solder joint was calculated using Coffin-Manson equation. Based on the calculated thermal fatigue life results, the range analysis was performed. The results of study show that that the impact sequence of the four factors from high to low on the fatigue life of PBGA solder joints are the stencil thickness,the upper pad diameter, the lower pad diameter and the chip weight on a single solder joint; the best level combination ofprocess parameters that results in the longest fatigue life is the lower pad diameter of 0.6 mm, the stencil thickness of 0.175 mm, the chip weight on asingle solder joint of 28×10-5 N and the upper pad diameter of 0.5 mm.

  3. Reliability Analysis of Surface Mount Technology (SMT)

    Science.gov (United States)

    1993-03-01

    1.3.6 Miscellaneous Components and Connectors ............................................. A-I 1 1.3.7 Aftermarket Lead Attachment ( AMLA ...Chip Inductor ....................................................................................... A-1 0 1.3.7 Typical Lead Detail of AMLA ...Attachment ( AMLA ) Various SMT studies have convincingly shown that soldering LCC’s (leadless ceramic chip carriers) to unconstrained printed wiring boards

  4. Research on Poor Solderability based on the SMT Process Technology%基于SMT的印制板可焊性不良工艺技术研究

    Institute of Scientific and Technical Information of China (English)

    孙亚芬; 安平

    2016-01-01

    There are more factors influencing the solderability of the PCB,and various technological process is very complex.It is difficult to control the overall quality of the PCB.Through combing and analyzing the production process, and combined with the test and verification,the quality problem of poor solderability is located.The methods have certain consulted value and reference significance to the quality problem analysis.%影响印制板可焊性的因素比较多,各种工艺流程比较复杂,批量印制板整体质量控制有一定的难度.通过对生产过程中的流程梳理和分析,并结合检验及试验验证,对引起印制板可焊性不良的原因进行了排查、分析和定位.该分析方法对于类似质量问题的排查具有一定的借鉴和指导意义.

  5. Surface Mobility Technology (SMT) Team member with Case Western Reserve University (CWRU) Students a

    Science.gov (United States)

    2006-01-01

    Surface Mobility Technology (SMT) Team member with Case Western Reserve University (CWRU) Students and Faculty in the Control Room of the Simulated Lunar Operations (SLOPE) Laboratory for the Modular Mobility Technology Demonstrator (MMTD)

  6. Surface Mobility Technology (SMT) Team members and Students and Faculty from Case Western Reserve Un

    Science.gov (United States)

    2006-01-01

    Surface Mobility Technology (SMT) Team members and Students and Faculty from Case Western Reserve University (CWRU) with the Modular Mobility Technology Demonstrator (MMTD) in the Simulated Lunar Operations (SLOPE) Laboratory

  7. Research and application of visual location technology for solder paste printing based on machine vision

    Institute of Scientific and Technical Information of China (English)

    Luosi WEI; Zongxia JIAO

    2009-01-01

    A location system is very important for solder paste printing in the process of surface mount technology (SMT). Using machine vision technology to complete the location mission is new and very efficient. This paper presents an integrated visual location system for solder paste printing based on machine vision. The working principle of solder paste printing is introduced and then the design and implementation of the visual location system are described. In the system, two key techniques are completed by secondary development based on VisionPro.One is accurate image location solved by the pattern-based location algorithms of PatMax. The other one is camera calibration that is achieved by image warping technology through the checkerboard plate. Moreover, the system can provide good performances such as high image locating accuracy with 1/40 sub-pixels, high anti-jamming, and high-speed location of objects whose appearance is rotated, scaled, and/or stretched.

  8. Integrated environmentally compatible soldering technologies. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, F.M.; Frear, D.R.; Iman, R.L.; Keicher, D.M.; Lopez, E.P.; Peebles, H.C.; Sorensen, N.R.; Vianco, P.T.

    1994-05-01

    Chemical fluxes are typically used during conventional electronic soldering to enhance solder wettability. Most fluxes contain very reactive, hazardous constituents that require special storage and handling. Corrosive flux residues that remain on soldered parts can severely degrade product reliability. The residues are removed with chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC), or other hazardous solvents that contribute to ozone depletion, release volatile organic compounds into the atmosphere, or add to the solvent waste stream. Alternative materials and processes that offer the potential for the reduction or elimination of cleaning are being developed to address these environmental issues. Timing of the effort is critical, since the targeted chemicals will soon be heavily taxed or banned. DOE`s Office of Environmental Restoration and Waste Management (DOE/EM) has supported Sandia National Laboratories` Environmentally Conscious Manufacturing Integrated Demonstration (ECMID). Part of the ECM program involves the integration of several environmentally compatible soldering technologies for assembling electronics devices. Fluxless or {open_quotes}low-residue/no clean{close_quotes} soldering technologies (conventional and ablative laser processing, controlled atmospheres, ultrasonic tinning, protective coatings, and environmentally compatible fluxes) have been demonstrated at Sandia (SNL/NM), the University of California at Berkeley, and Allied Signal Aerospace-Kansas City Division (AS-KCD). The university demonstrations were directed under the guidance of Sandia staff. Results of the FY93 Soldering ID are presented in this report.

  9. SMT焊接缺陷分析教学中头脑风暴法的应用%The Application of Brain-storming in the SMT Soldering Defect Analysis Teaching

    Institute of Scientific and Technical Information of China (English)

    刘晨

    2011-01-01

    BS(Brajn storming)法,最早意为精神病患者的精神错乱,而现在则衍生成为产生新观点和创新思维的激励方法.文章仅以此方法作为手段,在表面组装技术工艺教学中,循序渐进的激发学生的创新思维和分析能力,开拓思路,完成对于SMT工艺技术中最重要的内容--焊接缺陷的分析,达到了非常理想的教学效果.最后还简要的探讨了该方法的推广.%The method of BS (Brain Storming), initially being used to describe the symptom of patients with mental disorder. has been evolved to a pedagogy that stimulates innovative thinking and ideas. This article introduces the application of the method of BS in the teaching of Surface Mount Technology(SMT). The method of BS works as a very efficient instrument in the teaching to gradually stimulate students' ability of innovative thinking and analysis and especially the abilty to analyze soldering defect that is the most critical component of SMT. In the end, the article also discusses the spread of this method.

  10. Diagnosis of electronic systems in SMT technological line

    Science.gov (United States)

    Butor, Marcin; Dziurdzia, Barbara

    2016-12-01

    The paper presents test and inspection strategies used in the company Fideltronik Poland, Sucha Beskidzka during the process of assembly of advanced electronic systems. As the example, the manufacturing process of modules for controlling and configuration of charts for video transmission has been analyzed. Various diagnostic methods such as Solder Paste Inspection (SPI), Automated Optical Inspection (AOI), Automated X-ray Inspection AXI and Functional Circuit Test FCT have been used to detect failures at different manufacturing stages of the modules and various repair actions have been proposed .

  11. Integrating the TRIZ and Taguchi's Method in the Optimization of Processes Parameters for SMT

    Directory of Open Access Journals (Sweden)

    Yung-Tsan Jou

    2013-01-01

    Full Text Available SMT is an assembly technology for core circuit board parts. Unless process parameters are effectively controlled, poor solderability may result in a decline in product quality. This study looks at an SMT manufacturing process in a multinational company. First, the TRIZ contradiction matrix is revised to investigate the association between the 39 parameters in the contradiction matrix and 13 parameters that influence the unevenness of solder paste in the solder paste printing process. Expert verification is then used to screen the key factors affecting the quality of SMT, which are then combined with Taguchi's method to identify the optimal parameter set influencing the thickness of SMT solder paste. Results. TRIZ identifies squeegee pressure, ejection speed, squeegee speed, and squeegee angle as the four parameters with the greatest influence on SMT solder paste thickness. Taguchi's method is used to identify the optimum levels set for the experimental factors and carry out confirmation experiments. The S/N ratio improved from 21.732 db to 26.632 db, while the mean also improved from the current 0.163 mm to 0.155 mm, close to the target value of 0.15 mm. The results show that applying TRIZ and Taguchi's method for the purpose of product improvement is feasible.

  12. 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.

  13. Mechanical properties of QFP micro-joints soldered with lead-free solders using diode laser soldering technology

    Institute of Scientific and Technical Information of China (English)

    HAN Zong-jie; XUE Song-bai; WANG Jian-xin; ZHANG Xin; ZHANG Liang; YU Sheng-lin; WANG Hui

    2008-01-01

    Soldering experiments of quad flat package(QFP) devices were carried out by means of diode laser soldering system with Sn-Ag-Cu and Sn-Cu-Ni lead-free solders, and competitive experiments were also carried out not only with Sn-Pb eutectic solders but also with infrared reflow soldering method. The results indicate that under the conditions of laser continuous scanning mode as well as the fixed laser soldering time, an optimal power exists, while the optimal mechanical properties of QFP micro-joints are gained. Mechanical properties of QFP micro-joints soldered with laser soldering system are better than those of QFP micro-joints soldered with IR reflow soldering method. Fracture morphologies of QFP micro-joints soldered with laser soldering system exhibit the characteristic of tough fracture, and homogeneous and fine dimples appear under the optimal laser output power.

  14. 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

  15. 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.

  16. Cost comparison modeling between current solder sphere attachment technology and solder jetting technology

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, R.N.

    1996-10-01

    By predicting the total life-cycle cost of owning and operating production equipment, it becomes possible for processors to make accurate and intelligent decisions regarding major capitol equipment investments as well as determining the most cost effective manufacturing processes and environments. Cost of Ownership (COO) is a decision making technique based on inputting the total costs of acquiring, operating and maintaining production equipment. All quantitative economic and production data can be modeled and processed using COO software programs such as the Cost of Ownership Luminator program TWO COOL{trademark}. This report investigated the Cost of Ownership differences between the current state-of-the-art solder ball attachment process and a prototype solder jetting process developed by Sandia National Laboratories. The prototype jetting process is a novel and unique approach to address the anticipated high rate ball grid array (BGA) production requirements currently forecasted for the next decade. The jetting process, which is both economically and environmentally attractive eliminates the solder sphere fabrication step, the solder flux application step as well as the furnace reflow and post cleaning operations.

  17. Complex of automated equipment and technologies for waveguides soldering using induction heating

    Science.gov (United States)

    Murygin, A. V.; Tynchenko, V. S.; Laptenok, V. D.; Emilova, O. A.; Bocharov, A. N.

    2017-02-01

    The article deals with the problem of designing complex automated equipment for soldering waveguides based on induction heating technology. A theoretical analysis of the problem, allowing to form a model of the «inductor-waveguide» system and to carry out studies to determine the form of inducing wire, creating a narrow and concentrated heat zone in the area of the solder joint. Also solves the problem of the choice of the temperature control means, the information from which is used later to generate the effective management of induction soldering process. Designed hardware complex in conjunction with the developed software system is a system of automatic control, allowing to manage the process of induction heating, to prevent overheating and destruction of the soldered products, improve the stability of induction soldering process, to improve the quality of products, thereby reducing time and material costs for the production.

  18. Solder technology in the manufacturing of electronic products

    Energy Technology Data Exchange (ETDEWEB)

    Vianco, P.T.

    1993-08-01

    The electronics industry has relied heavily upon the use of soldering for both package construction and circuit assembly. The solder attachment of devices onto printed circuit boards and ceramic microcircuits has supported the high volume manufacturing processes responsible for low cost, high quality consumer products and military hardware. Defects incurred during the manufacturing process are minimized by the proper selection of solder alloys, substrate materials and process parameters. Prototyping efforts are then used to evaluate the manufacturability of the chosen material systems. Once manufacturing feasibility has been established, service reliability of the final product is evaluated through accelerated testing procedures.

  19. Reliability of lead-free solders in electronic packaging technology

    Science.gov (United States)

    Choi, Woojin

    The electromigration of flip chip solder bump (eutetic SnPb) has been studied at temperatures of 100, 125 and 150°C and current densities of 1.9 to 2.75 x 104 A/cm2. The under-bump-metallization on the chip side is thin film Al/Ni(V)/Cu and on the board side is thick Cu. By simulation, we found that current crowding occurs at the corner on the chip side where the electrons enter the solder ball. We are able to match this simulation to the real electromigration damage in the sample. The experimental result showed that voids initiated from the position of current crowding and propagated across the interface between UBM and the solder ball. The Cu-Sn intermetallic compounds formed during the reflow is known to adhere well to the thin film UBM, but they detached from the UBM after current stressing. Therefore, the UBM itself becomes part of the reliability problem of the flip chip solder joint under electromigration. Currently there is a renewed interest in Sn whisker growth owing to the introduction of Pb-free solder in electronic manufacturing. The leadframe is electroplated or finished with a layer of Pb-free solder. The solder is typically pure Sn or eutectic SnCu (0.7 atomic % Cu). It is a serious reliability concern in the use of the eutectic SnCu solder as leadframe surface finish due to the growth of long whiskers on it. The origin of the driving force of compressive stress can be mechanical, thermal, and chemical. Among them, the chemical force is the most important contribution to the whisker growth and its origin is due to the reaction between Sn and Cu to form intermetallic compound (IMC) at room temperature. For whisker or hillock growth, the surface cannot be free of oxide and it must be covered with oxide and the oxide must be a protective one so that it removes effectively all the vacancy sources and sinks on the surface. Hence, only those metals, which grow protective oxides such as Al and Sn, are known to have hillock growth or whisker growth. We

  20. 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...

  1. Evaluation technology of lead-free solders; Namari free handa zairyo ni okeru hyoka gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Yamashita, M.; Shiokawa, K. [Fuji Electric Co. Ltd., Tokyo (Japan); Ueda, A. [Fuji Electric Corporate Research and Development,Ltd., Kanagawa (Japan)

    2000-09-10

    Solders mainly composed of tin and lead are currently in widespread use in semiconductor devices. However, in view of lead influences on the human body and environmental problems, lead-free solders have been in urgent demand. In this study, aiming to improve the solderability and reliability of a tin-silver solder, one of most promising lead-free solder materials, we have investigated elements to be added. Focusing on typical lead-free tin-silver solders and tin-lead eutectic solders, this paper describes the result of investigations into the mechanical properties solderability, micro structures of the solder materials and gas analysis in soldering. (author)

  2. Rewriting Modulo SMT

    Science.gov (United States)

    Rocha, Camilo; Meseguer, Jose; Munoz, Cesar A.

    2013-01-01

    Combining symbolic techniques such as: (i) SMT solving, (ii) rewriting modulo theories, and (iii) model checking can enable the analysis of infinite-state systems outside the scope of each such technique. This paper proposes rewriting modulo SMT as a new technique combining the powers of (i)-(iii) and ideally suited to model and analyze infinite-state open systems; that is, systems that interact with a non-deterministic environment. Such systems exhibit both internal non-determinism due to the system, and external non-determinism due to the environment. They are not amenable to finite-state model checking analysis because they typically are infinite-state. By being reducible to standard rewriting using reflective techniques, rewriting modulo SMT can both naturally model and analyze open systems without requiring any changes to rewriting-based reachability analysis techniques for closed systems. This is illustrated by the analysis of a real-time system beyond the scope of timed automata methods.

  3. Quality investigation of surface mount technology using phase-shifting digital holography

    Science.gov (United States)

    Boonsri, Chantira; Buranasiri, Prathan

    2016-09-01

    Applying of a phase-shifting digital holography combined with compressive sensing to inspect the soldering quality of surface mount technology (SMT) which is a method for producing electronic circuits. In SMT, the components are mounted and connected with each other directly onto the surface of printed circuit boards (PCBs). By reconstructing the multidimensional images from a few samples of SMT, the results are solved by an optimization problem. In this paper, two problems have been concerned. The first one is to examine the devices and the soldering quality of connections between them, which are in micro-scaled. The second is to observe the effect of heat treatment of soldering material and devices on the surface mount board.

  4. Manual Soldering Process Technology (continued)%手工软钎焊工艺技术(待续)

    Institute of Scientific and Technical Information of China (English)

    史建卫; 檀正东; 周璇; 苏立军; 杜彬

    2014-01-01

    Manual soldering is one of the basic process technologies in PCB assembly and rework. Mainly elaborate manual soldering process in detail aiming at the site requirements, soldering tools selection, process parameter setting, component assembly and repair and other related content. Provide important reference for manual soldering practitioners.%手工软钎焊是PCB组装和返修工艺中基本的工艺技术之一。主要针对现场要求、焊接工具选择、工艺参数设定、元件组装焊接及返修拆焊等相关内容,对手工软钎焊工艺技术进行详细阐述,为手工焊接从业者提供重要参考依据。

  5. Manual Soldering Process Technology (continued)%手工软钎焊工艺技术(续三)

    Institute of Scientific and Technical Information of China (English)

    史建卫; 檀正东; 周璇; 苏立军; 杜彬

    2015-01-01

    Manual soldering is one of the basic process technologies in PCB assembly and rework. Mainly elaborate manual soldering process in detail aiming at the site requirements, soldering tools selection, process parameter setting, component assembly and repair and other related content. Provide important reference for manual soldering practitioners.%手工软钎焊是PCB组装和返修工艺中基本的工艺技术之一。主要针对现场要求、焊接工具选择、工艺参数设定、元件组装焊接及返修拆焊等相关内容,对手工软钎焊工艺技术进行详细阐述,为手工焊接从业者提供重要参考依据。

  6. Manual Soldering Process Technology (continued)%手工软钎焊工艺技术(续二)

    Institute of Scientific and Technical Information of China (English)

    史建卫; 檀正东; 周璇; 苏立军; 杜彬

    2015-01-01

    Manual soldering is one of the basic process technologies in PCB assembly and rework. Mainly elaborate manual soldering process in detail aiming at the site requirements, soldering tools selection, process parameter setting, component assembly and repair and other related content. Provide important reference for manual soldering practitioners.%手工软钎焊是PCB组装和返修工艺中基本的工艺技术之一。主要针对现场要求、焊接工具选择、工艺参数设定、元件组装焊接及返修拆焊等相关内容,对手工软钎焊工艺技术进行详细阐述,为手工焊接从业者提供重要参考依据。

  7. 手工软钎焊工艺技术(续完)%Manual Soldering Process Technology ( continued )

    Institute of Scientific and Technical Information of China (English)

    史建卫; 檀正东; 周璇; 苏立军; 杜彬

    2015-01-01

    Manual soldering is one of the basic process technologies in PCB assembly and rework. Mainly elaborate manual soldering process in detail aiming at the site requirements, soldering tools selection, process parameter setting, component assembly and repair and other related content. Provide important reference for manual soldering practitioners.%手工软钎焊是PCB组装和返修工艺中基本的工艺技术之一.主要针对现场要求、焊接工具选择、工艺参数设定、元件组装焊接及返修拆焊等相关内容,对手工软钎焊工艺技术进行详细阐述,为手工焊接从业者提供重要参考依据.

  8. 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.

  9. 航空产品混装PCB回流焊工艺优化%Optimizing of Mixed PCB Technology of Reflow Soldering for Aeronautical Product

    Institute of Scientific and Technical Information of China (English)

    凌月红

    2013-01-01

    SMT welding method is used more and more frequently in aeronautical electronics PCB. Many defects in spot weld such as BGA empty holes and weak jointing come from reflow soldering temperature adjustment. In this paper, the author derives the best reflow soldering temperature with oven temperature testing instruments and thrust experiments , satisfying PCB soldering quality requirements and is highly adaptable.%  目前航空电子产品印制电路板(PCB)焊接方式越来越多采用表面贴装技术(SMT),而最能体现SMT回流焊工艺能力的参数指标是回流焊曲线。很多焊点的缺陷,特别是目前较难控制与解决的球栅阵列封装器件(BGA:Ball Grid Array)空洞以及虚焊等隐性缺陷都来源于回流焊温度参数的设定。本文运用炉温测试仪和推力试验,结合实验设计获得最优化的参数设定,最终找到混装 PCB 的最佳回流炉温度曲线,满足了混装PCB焊接质量要求,且具有较强的适应能力。

  10. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, J.D.; Stein, B.A.

    1986-01-01

    This book presents recent advances in joining technologies for the 1990s-welding, brazing, soldering, mechanical fastening, explosive welding, solid-state bonding, and adhesive bonding. A major consideration in the fabrication of any commercial, military, or space product is attachment systems which are safe and reliable. The subject matter covered includes technology developed in current research programs relevant to welding, bonding, and fastening of structural materials, for fabricating structures and mechanical systems use in the aerospace, automotive, and related industries. Specific topics include equipment, hardware and materials used when welding, brazing, and soldering; mechanical fastening; explosive welding; use of unique selected joining techniques; adhesive bonding; and nondestructive evaluation. ''The Factory of the Future'' is 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.

  12. Electrical Resistance of Nb3Sn/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 Nb3Sn/Cu strands is a key issue for the construction of Nb3Sn based damping ring wigglers and insertion devices for third generation light sources. We compare the electrical resistance of Nb3Sn/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 the strand matr...

  13. Microstructure and Reliability Comparison of Different Pb-Free Alloys Used for Wave Soldering and Rework

    Science.gov (United States)

    Snugovsky, Polina; Bagheri, Zohreh; Hamilton, Craig

    2009-12-01

    This paper describes the results of an intensive microstructural and reliability study of pin-through-hole (PTH) and surface mount technology (SMT) components which were wave solder assembled using three groups of alloys: (1) near-eutectic Sn-Ag-Cu alloys such as SAC405 and SAC305, (2) low-Ag off-eutectic Pb-free alloys with an Ag content of about 1% and lower, and (3) eutectic Sn-Cu alloys with Ni and other additives. Both primary attach and reworked solder connections using solder fountain and hand rework were studied. The PTH connector types and SMT components were wave solder assembled on a test vehicle. Accelerated thermal cycling (ATC) was conducted at 0°C to 100°C for 6000 cycles. The difference in microstructures, intermetallic formation, Cu dissolution, grain coarsening, and crack formation is shown. The influence of the microstructure after assembly and rework on Weibull plot parameters and failure modes is described for 2512 resistors. Interconnect defects such as nonuniform phase distribution and void formation are discussed. The Sn-Cu-Ni- and Sn-Cu-Ag-Bi-based alloys tested in this study are recommended as potential suitable replacements for SAC305/405 in the wave solder process; no failure was detected up to 6000 cycles at 0°C to 100°C. Although SAC405 demonstrated better barrel fill and lower rate of crack propagation during ATC, after PTH rework, both of the alternative Pb-free alloys have a much lower Cu dissolution rate and definitely outperform SAC405 in ATC. SAC405 glue and wave resistors after primary attachment and rework demonstrate higher reliability than alternative alloys. Early failures relate to alternative alloy characteristics and should be considered for some applications.

  14. The automated system for technological process of spacecraft's waveguide paths soldering

    Science.gov (United States)

    Tynchenko, V. S.; Murygin, A. V.; Emilova, O. A.; Bocharov, A. N.; Laptenok, V. D.

    2016-11-01

    The paper solves the problem of automated process control of space vehicles waveguide paths soldering by means of induction heating. The peculiarities of the induction soldering process are analyzed and necessity of information-control system automation is identified. The developed automated system makes the control of the product heating process, by varying the power supplied to the inductor, on the basis of information about the soldering zone temperature, and stabilizing the temperature in a narrow range above the melting point of the solder but below the melting point of the waveguide. This allows the soldering process automating to improve the quality of the waveguides and eliminate burn-troughs. The article shows a block diagram of a software system consisting of five modules, and describes the main algorithm of its work. Also there is a description of the waveguide paths automated soldering system operation, for explaining the basic functions and limitations of the system. The developed software allows setting of the measurement equipment, setting and changing parameters of the soldering process, as well as view graphs of temperatures recorded by the system. There is shown the results of experimental studies that prove high quality of soldering process control and the system applicability to the tasks of automation.

  15. 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%.

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

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, J.D.; Stein, B.A.

    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. For individual titles see N86-11228 through N86-11255.

  17. 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.

  18. Manual Soldering Process Technology (continued)%手工软钎焊工艺技术(续一)实用电子组装技术

    Institute of Scientific and Technical Information of China (English)

    史建卫; 檀正东; 周璇; 苏立军; 杜彬

    2014-01-01

    Manual soldering is one of the basic process technologies in PCB assembly and rework. Mainly elaborate manual soldering process in detail aiming at the site requirements, soldering tools selection, process parameter setting, component assembly and repair and other related content. Provide important reference for manual soldering practitioners.%手工软钎焊是PCB组装和返修工艺中基本的工艺技术之一。主要针对现场要求、焊接工具选择、工艺参数设定、元件组装焊接及返修拆焊等相关内容,对手工软钎焊工艺技术进行详细阐述,为手工焊接从业者提供重要参考依据。

  19. Wetting behavior of alternative solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, F.M.; Vianco, P.T.; Hernandez, C.L.; Rejent, J.A.

    1993-07-01

    Recent economic and environmental issues have stimulated interest in solder alloys other than the traditional Sn-Pb eutectic or near eutectic composition. Preliminary evaluations suggest that several of these alloys approach the baseline properties (wetting, mechanical, thermal, and electrical) of the Sn-Pb solders. Final alloy acceptance will require major revisions to existing industrial and military soldering specifications. Bulk alloy and solder joint properties are consequently being investigated to validate their producibility and reliability. The work reported in this paper examines the wetting behavior of several of the more promising commercial alloys on copper substrates. Solder wettability was determined by the meniscometer and wetting balance techniques. The wetting results suggest that several of the alternative solders would satisfy pretinning and surface mount soldering applications. Their use on plated through hole technology might be more difficult since the alloys generally did not spread or flow as well as the 60Sn-40Pb solder.

  20. Wave soldering with Pb-free solders

    Energy Technology Data Exchange (ETDEWEB)

    Artaki, I.; Finley, D.W.; Jackson, A.M.; Ray, U. [AT and T Bell Labs., Princeton, NJ (United States); Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States)

    1995-07-01

    The manufacturing feasibility and attachment reliability of a series of newly developed lead-free solders were investigated for wave soldering applications. Some of the key assembly aspects addressed included: wettability as a function of board surface finish, flux activation and surface tension of the molten solder, solder joint fillet quality and optimization of soldering thermal profiles. Generally, all new solder formulations exhibited adequate wave soldering performance and can be considered as possible alternatives to eutectic SnPb for wave soldering applications. Further process optimization and flux development is necessary to achieve the defect levels associated with the conventional SnPb process.

  1. vZ - An Optimizing SMT Solver

    DEFF Research Database (Denmark)

    Bjørner, Nikolaj; Dung, Phan Anh; Fleckenstein, Lars

    2015-01-01

    vZ is a part of the SMT solver Z3. It allows users to pose and solve optimization problems modulo theories. Many SMT applications use models to provide satisfying assignments, and a growing number of these build on top of Z3 to get optimal assignments with respect to objective functions. vZ provi...

  2. Rewriting Modulo SMT and Open System Analysis

    Science.gov (United States)

    Rocha, Camilo; Meseguer, Jose; Munoz, Cesar

    2014-01-01

    This paper proposes rewriting modulo SMT, a new technique that combines the power of SMT solving, rewriting modulo theories, and model checking. Rewriting modulo SMT is ideally suited to model and analyze infinite-state open systems, i.e., systems that interact with a non-deterministic environment. Such systems exhibit both internal non-determinism, which is proper to the system, and external non-determinism, which is due to the environment. In a reflective formalism, such as rewriting logic, rewriting modulo SMT can be reduced to standard rewriting. Hence, rewriting modulo SMT naturally extends rewriting-based reachability analysis techniques, which are available for closed systems, to open systems. The proposed technique is illustrated with the formal analysis of: (i) a real-time system that is beyond the scope of timed-automata methods and (ii) automatic detection of reachability violations in a synchronous language developed to support autonomous spacecraft operations.

  3. Recycling of organic materials and solder from waste printed circuit boards by vacuum pyrolysis-centrifugation coupling technology.

    Science.gov (United States)

    Zhou, Yihui; Wu, WenBiao; Qiu, Keqiang

    2011-12-01

    Here, we focused on the recycling of waste printed circuit boards (WPCBs) using vacuum pyrolysis-centrifugation coupling technology (VPCT) aiming to obtain valuable feedstock and resolve environmental pollution. The two types of WPCBs were pyrolysed at 600°C for 30 min under vacuum condition. During the pyrolysis process, the solder of WPCBs was separated and recovered when the temperature range was 400-600°C, and the rotating drum was rotated at 1000 rpm for 10 min. The type-A of WPCBs pyrolysed to form an average of 67.91 wt.% residue, 27.84 wt.% oil, and 4.25 wt.% gas; and pyrolysis of the type-B of WPCBs led to an average mass balance of 72.22 wt.% residue, 21.57 wt.% oil, and 6.21 wt.% gas. The GC-MS and FT-IR analyses showed that the two pyrolysis oils consisted mainly of phenols and substituted phenols. The pyrolysis oil can be used for fuel or chemical feedstock for further processing. The recovered solder can be recycled directly and it can also be a good resource of lead and tin for refining. The pyrolysis residues contained various metals, glass fibers and other inorganic materials, which could be recovered after further treatment. The pyrolysis gases consisted mainly of CO, CO(2), CH(4), and H(2), which could be collected and recycled.

  4. 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

  5. Homologi Gen Seleno Metiltransferase (smt pada Geobacillus sp. 20k dengan smt Astragalus bisulcatus

    Directory of Open Access Journals (Sweden)

    Evi Triana

    2010-09-01

    Full Text Available Methylselenocysteine (MSC is the most effective form of selenium against cancer. The synthesis of MSC is catalyzed by seleno methyltransferase (smt through selenium methylation as its detoxification mechanism. Gene of smt has been characterized in selenium rich plant, Astragalus bisulcatus. This experimental laboratoric study was done on Geobacillus sp. 20k. at Lembaga Ilmu Pengetahuan Indonesia (LIPI, Cibinong, Bogor, November 2008–June 2009.Target gene was detected by polymerase chain reaction and sequencing. DNA sequence was analyzed by the basic local alignment search tool (BLAST. The results showed that smt gene and its homolog were generally found on selenium rich plants, such as A. bisulcatus, C. sinensis, and A. thaliana, with similarity more than 85%. Designed primers for amplification of smt are CAAGCCACCATTCAAGGTTT and CCCTACTGATCCCGCAATTA. Amplification of DNA fragments obtained at approximately 190 base pair. DNA sequence and its protein translation were identified as part of the thermophilic enzyme and smt of A. bisulcatus, with 83% similarity for smt genes and 88–90% for protein. In conclusion, Geobacillus sp. 20k have smt genes similar with that of A. bisulcatus, therefore further development of this isolate as a non toxic selenium source for cancer therapy could be taken into consideration.

  6. Predicting SMT Solver Performance for Software Verification

    Directory of Open Access Journals (Sweden)

    Andrew Healy

    2017-01-01

    Full Text Available The Why3 IDE and verification system facilitates the use of a wide range of Satisfiability Modulo Theories (SMT solvers through a driver-based architecture. We present Where4: a portfolio-based approach to discharge Why3 proof obligations. We use data analysis and machine learning techniques on static metrics derived from program source code. Our approach benefits software engineers by providing a single utility to delegate proof obligations to the solvers most likely to return a useful result. It does this in a time-efficient way using existing Why3 and solver installations - without requiring low-level knowledge about SMT solver operation from the user.

  7. Parametric study on the solderability of etched PWB copper

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, F.M.; Stevenson, J.O.; Hernandez, C.L.

    1996-10-01

    The rapid advancement of interconnect technology has resulted in a more engineered approach to designing and fabricating printed wiring board (PWB) surface features. Recent research at Sandia National Laboratories has demonstrated the importance of surface roughness on solder flow. This paper describes how chemical etching was used to enhance the solderability of surfaces that were normally difficult to wet. The effects of circuit geometry, etch concentration, and etching time on solder flow are discussed. Surface roughness and solder flow data are presented. The results clearly demonstrate the importance of surface roughness on the solderability of fine PWB surface mount features.

  8. Study on Organization and Operation Mode of SMT-MG

    Institute of Scientific and Technical Information of China (English)

    LI Chunquan; YU Tao; ZHOU Dejian

    2006-01-01

    SMT-MG is a typical application of grid in electric product manufacturing. The organization and operation mode are key problems in SMT-MG. In this paper, SMT-MG is taken as research object. Its mesh three-dimensional matrix organization mode is presented. Meanwhile from operation foundation, process, environment and target four aspects, operation principles are explored. Operation mechanisms of SMT-MG such as adaptive evolution, PUSH/PULL driving, cooperation and game, feedback, regulation/control, coordination, impetus mechanism and so on are studied. Finally, the operation flow of SMT-MG is introduced.

  9. Recent Research Trend in Laser-Soldering Process

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hwan Tae; Kil, Sang Cheol [Korea Institute of Science and Technology Information, Seoul (Korea, Republic of); Hwang, Woon Suk [Inha University, Incheon (Korea, Republic of)

    2009-10-15

    The trend of the microjoining technology by the laser-soldering process has been reviewed. Among the production technologies, joining technology plays an important role in the fabrication of electronic components. This has led to an increasing attention towards the use of modem microjoining technology such as micro-resistance spot joining micro-soldering, micro-friction stir joining and laser-soldering, etc. This review covers the recent technical trends of laser-soldering collected from the COMPENDEX DB analysis of published papers, research subject and research institutes.

  10. Instantiation of SMT problems modulo Integers

    CERN Document Server

    Echenim, Mnacho

    2010-01-01

    Many decision procedures for SMT problems rely more or less implicitly on an instantiation of the axioms of the theories under consideration, and differ by making use of the additional properties of each theory, in order to increase efficiency. We present a new technique for devising complete instantiation schemes on SMT problems over a combination of linear arithmetic with another theory T. The method consists in first instantiating the arithmetic part of the formula, and then getting rid of the remaining variables in the problem by using an instantiation strategy which is complete for T. We provide examples evidencing that not only is this technique generic (in the sense that it applies to a wide range of theories) but it is also efficient, even compared to state-of-the-art instantiation schemes for specific theories.

  11. Assessment of potential solder candidates for high temperature applications

    DEFF Research Database (Denmark)

    Multi-Chip module (MCM) technology is a specialized electronic packaging technology recently gaining momentum due to the miniaturization drive in the microelectronics industry. The step soldering approach is being employed in the MCM technology. This method is used to solder various levels...... of the package with different solders of different melting temperatures. High Pb containing alloys where the lead levels can be above 85% by weight, is one of the solders currently being used in this technology. Responding to market pressure i.e. need for green electronic products there is now an increasing...... 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...

  12. Capillary flow of solder on chemically roughened PWB surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, F.M.; Stevenson, J.O.; Yost, F.G.

    1996-02-01

    The Center for Solder Science and Technology at Sandia National Laboratories has developed a solderability test for evaluating fundamental solder flow over PWB (printed wiring boards) surface finishes. The work supports a cooperative research and development agreement between Sandia, the National Center for Manufacturing Sciences (NCMS), and several industrial partners. An important facet of the effort involved the ``engineering`` of copper surfaces through mechanical and chemical roughening. The roughened topography enhances solder flow, especially over very fine features. In this paper, we describe how etching with different chemical solutions can affect solder flow on a specially designed ball grid array test vehicle (BGATV). The effects of circuit geometry, solution concentration, and etching time are discussed. Surface roughness and solder flow data are presented to support the roughening premise. Noticeable improvements in solder wettability were observed on uniformly etched surfaces having relatively steep peak-to-valley slopes.

  13. Modelling and Analysis for Cyber-Physical Systems: An SMT-based approach

    DEFF Research Database (Denmark)

    Dung, Phan Anh

    , better designs have positive impacts on the product quality, development time and price, etc. We developed tools, theories and techniques that make use of SMT solving as a back-end engine for analysis and employ Duration Calculus as a front-end technology for modelling. The proposed techniques have been...

  14. School-Based Curriculum Development: A Proposal for Improving Girls' Performance in SMT.

    Science.gov (United States)

    Mulemwa, Jane N.

    The paper discusses the process and logistical experiences of developing science, technology and mathematics (SMT) curricula materials at the primary and secondary school levels in Uganda. The author developed the approach as part of the Female Education in Mathematics and Science in Africa (FEMSA) project. FEMSA is an Africa regional project that…

  15. Solder flow over fine line PWB surface finishes

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, F.M.; Hernandez, C.L.

    1998-08-01

    The rapid advancement of interconnect technology has stimulated the development of alternative printed wiring board (PWB) surface finishes to enhance the solderability of standard copper and solder-coated surfaces. These new finishes are based on either metallic or organic chemistries. As part of an ongoing solderability study, Sandia National Laboratories has investigated the solder flow behavior of two azole-based organic solderability preservations, immersion Au, immersion Ag, electroless Pd, and electroless Pd/Ni on fine line copper features. The coated substrates were solder tested in the as-fabricated and environmentally-stressed conditions. Samples were processed through an inerted reflow machine. The azole-based coatings generally provided the most effective protection after aging. Thin Pd over Cu yielded the best wetting results of the metallic coatings, with complete dissolution of the Pd overcoat and wetting of the underlying Cu by the flowing solder. Limited wetting was measured on the thicker Pd and Pd over Ni finishes, which were not completely dissolved by the molten solder. The immersion Au and Ag finishes yielded the lowest wetted lengths, respectively. These general differences in solderability were directly attributed to the type of surface finish which the solder came in contact with. The effects of circuit geometry, surface finish, stressing, and solder processing conditions are discussed.

  16. 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.

  17. Organic solderability preservation evaluation. Topical report

    Energy Technology Data Exchange (ETDEWEB)

    Becka, G.A.; McHenry, M.R.; Slanina, J.T.

    1997-03-01

    An evaluation was conducted to determine the possible replacement of the hot air solder leveling (HASL) process used in the Allied Signal Federal Manufacturing & Technologies (FM&T) Printed Wiring Board Facility with an organic solderability preservative (OSP). The drivers for replacing HASL include (1) Eliminating lead from PWB fabrication processes; (2) Potential legislation restricting use of lead, (3) Less expensive processing utilizing OSP rather than HASL processing; (4) Avoiding solder dross disposal inherent with HASL processing, (5) OSP provides flat, planar surface required for surface mount technology product, and (6) Trend to thinner PWB designs. A reduction in the cost of nonconformance (CONC) due to HASL defects (exposed copper, solderability, dewetting and non-wetting) would be realized with the incorporation of the OSP process. Several supplier HASL replacement candidates were initially evaluated. One supplier chemistry was chosen for potential use in the FM&T PWB and assembly areas.

  18. Certified Satisfiability Module Theories (SMT) Solving for System Verification

    Science.gov (United States)

    2017-01-01

    CERTIFIED SATISFIABILITY MODULO THEORIES (SMT) SOLVING FOR SYSTEM VERIFICATION NEW YORK UNIVERSITY JANUARY 2017 FINAL TECHNICAL REPORT APPROVED...COVERED (From - To) AUG 2013 – JUL 2016 4. TITLE AND SUBTITLE CERTIFIED SATISFIABILITY MODULO THEORIES (SMT) SOLVING FOR SYSTEM VERIFICATION 5a...describes the results of efforts to do exactly this. CVC4, a modern, open - source solver for Satisfiability Modulo Theories (SMT), has been instrumented

  19. SNL initiatives in electronic fluxless soldering

    Science.gov (United States)

    Hosking, F. M.; Frear, D. R.; Vianco, P. T.; Keicher, D. M.

    Conventional soldering of electronic components generally requires the application of a chemical flux to promote solder wetting and flow. Chlorofluorocarbons (CFC) and halogenated solvents are normally used to remove the resulting flux residues. While such practice has been routinely accepted throughout the electronics industry, the environmental impact of hazardous solvents on ozone depletion will eventually limit or prevent their use. Solvent substitution or alternative technologies must be developed to meet these goals. Sandia National Laboratories (SNL), Albuquerque has a comprehensive environmentally conscious electronics manufacturing program underway that is funded by the DOE Office of Technology Development. Primary elements of the integrated task are the characterization and development of alternative fluxless soldering technologies that would eliminate circuit board cleaning associated with flux residue removal. Storage and handling of hazardous solvents and mixed solvent-flux waste would be consequently reduced during electronics soldering. This paper will report on the progress of the SNL fluxless soldering initiative. Emphasis is placed on the use of controlled atmospheres, laser heating, and ultrasonic soldering.

  20. Thin concentrator photovoltaic module with micro-solar cells which are mounted by self-align method using surface tension of melted solder

    Science.gov (United States)

    Hayashi, Nobuhiko; Terauchi, Masaharu; Aya, Youichirou; Kanayama, Shutetsu; Nishitani, Hikaru; Nakagawa, Tohru; Takase, Michihiko

    2017-09-01

    We are developing a thin and lightweight CPV module using small size lens system made from poly methyl methacrylate (PMMA) with a short focal length and micro-solar cells to decrease the transporting and the installing costs of CPV systems. In order to achieve high conversion efficiency in CPV modules using micro-solar cells, the micro-solar cells need to be mounted accurately to the irradiated region of the concentrated sunlight. In this study, we have successfully developed self-align method thanks to the surface tension of the melted solder even utilizing commercially available surface-mounting technology (SMT). Solar cells were self-aligned to the specified positions of the circuit board by this self-align method with accuracy within ±10 µm. We actually fabricated CPV modules using this self-align method and demonstrated high conversion efficiency of our CPV module.

  1. Solderability test system

    Energy Technology Data Exchange (ETDEWEB)

    Yost, Fred (Cedar Crest, NM); Hosking, Floyd M. (Albuquerque, NM); Jellison, James L. (Albuquerque, NM); Short, Bruce (Beverly, MA); Giversen, Terri (Beverly, MA); Reed, Jimmy R. (Austin, TX)

    1998-01-01

    A new test method to quantify capillary flow solderability on a printed wiring board surface finish. The test is based on solder flow from a pad onto narrow strips or lines. A test procedure and video image analysis technique were developed for conducting the test and evaluating the data. Feasibility tests revealed that the wetted distance was sensitive to the ratio of pad radius to line width (l/r), solder volume, and flux predry time.

  2. Solderability test system

    Energy Technology Data Exchange (ETDEWEB)

    Yost, F.; Hosking, F.M.; Jellison, J.L.; Short, B.; Giversen, T.; Reed, J.R.

    1998-10-27

    A new test method to quantify capillary flow solderability on a printed wiring board surface finish. The test is based on solder flow from a pad onto narrow strips or lines. A test procedure and video image analysis technique were developed for conducting the test and evaluating the data. Feasibility tests revealed that the wetted distance was sensitive to the ratio of pad radius to line width (l/r), solder volume, and flux predry time. 11 figs.

  3. PWB solder wettability after simulated storage

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, C.L.; Hosking, F.M.

    1996-03-01

    A new solderability test method has been developed at Sandia National Laboratories that simulates the capillary flow physics of solders on circuit board surfaces. The solderability test geometry was incorporated on a circuit board prototype that was developed for a National Center for Manufacturing Sciences (NCMS) program. The work was conducted under a cooperative research and development agreement between Sandia National Laboratories, NCMS, and several PWB fabricators (AT&T, IBM, Texas Instruments, United Technologies/Hamilton Standard and Hughes Aircraft) to advance PWB interconnect technology. The test was used to investigate the effects of environmental prestressing on the solderability of printed wiring board (PWB) copper finishes. Aging was performed in a controlled chamber representing a typical indoor industrial environment. Solderability testing on as-fabricated and exposed copper samples was performed with the Sn-Pb eutectic solder at four different reflow temperatures (215, 230, 245 and 260{degrees}C). Rosin mildly activated (RMA), low solids (LS), and citric acid-based (CA) fluxes were included in the evaluation. Under baseline conditions, capillary flow was minimal at the lowest temperatures with all fluxes. Wetting increased with temperature at both baseline and prestressing conditions. Poor wetting, however, was observed at all temperatures with the LS flux. Capillary flow is effectively restored with the CA flux.

  4. Reduced oxide soldering activation (ROSA) PWB solderability testing

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, C.L.; Hosking, F.M. [Sandia National Labs., Albuquerque, NM (United States). Physical and Joining Metallurgy Dept.; Reed, J. [Texas Instruments, Austin, TX (United States); Tench, D.M.; White, J. [Rockwell Science Center, Thousand Oaks, CA (United States)

    1996-02-01

    The effect of ROSA pretreatment on the solderability of environmentally stressed PWB test coupons was investigated. The PWB surface finish was an electroplated, reflowed solder. Test results demonstrated the ability to recover plated-through-hole fill of steam aged samples with solder after ROSA processing. ROSA offers an alternative method for restoring the solderability of aged PWB surfaces.

  5. 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, co...

  6. Photonic flash soldering of thin chips and SMD components on foils for flexible electronics

    NARCIS (Netherlands)

    Ende, D.A. van den; Hendriks, R.; Cauchois, R.; Kusters, R.H.L.; Cauwe, M.; Groen, W.A.; Brand, J. van den

    2014-01-01

    Ultrathin bare die chips and small-size surface mount device components were successfully soldered using a novel roll-to-roll compatible soldering technology. A high-power xenon light flash was used to successfully solder the components to copper tracks on polyimide (PI) and polyethylene terephthala

  7. Assessment of potential solder candidates for high temperature applications

    DEFF Research Database (Denmark)

    of the package with different solders of different melting temperatures. High Pb containing alloys where the lead levels can be above 85% by weight, is one of the solders currently being used in this technology. Responding to market pressure i.e. need for green electronic products there is now an increasing...

  8. Lead-free solder

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Iver E. (Ames, IA); Terpstra, Robert L. (Ames, IA)

    2001-05-15

    A Sn--Ag--Cu eutectic alloy is modified with one or more low level and low cost alloy additions to enhance high temperature microstructural stability and thermal-mechanical fatigue strength without decreasing solderability. Purposeful fourth or fifth element additions in the collective amount not exceeding about 1 weight % (wt. %) are added to Sn--Ag--Cu eutectic solder alloy based on the ternary eutectic Sn--4.7%Ag--1.7%Cu (wt. %) and are selected from the group consisting essentially of Ni, Fe, and like-acting elements as modifiers of the intermetallic interface between the solder and substrate to improve high temperature solder joint microstructural stability and solder joint thermal-mechanical fatigue strength.

  9. Removing Dross From Molten Solder

    Science.gov (United States)

    Webb, Winston S.

    1990-01-01

    Automatic device helps to assure good solder connections. Machine wipes dross away from area on surface of molten solder in pot. Sweeps across surface of molten solder somewhat in manner of windshield wiper. Each cycle of operation triggered by pulse from external robot. Equipment used wherever precise, automated soldering must be done to military specifications.

  10. 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 for inte......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...

  11. Development of CANDU advanced fuel fabrication technology - A development of amorphous alloys for the solder of nuclear reactor materials

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jai Young; Lee, Ki Young; Kim, Yoon Kee; Jung, Jae Han; Yu, Ji Sang; Kim, Hae Yeol; Han, Young Su [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1996-07-01

    In the case of advanced CANDU fuel being useful in future, the fabrication processes for soundness insurance of a improved nuclear fuel bundle must be developed at the same time because it have three times combustibility as existing fuel. In particular, as the improved nuclear fuel bundle in which a coated layer thickness is thinner than existing that, firmity of a joint part is very important. Therefore, we need to develop a joint technique using new solder which can settle a potential problem in current joining method. As the Zr-Be alloy system and the Ti-Be system are composed with the elements having high neutron permeability, they are suitable for joint of nuclear fuel pack. The various compositions Zr-Be and Ti-Be binary metallic glass alloys were applicable to the joining the nuclear fuel bundles. The thickness of joint layer using the Zr{sub 1-x} Be{sub x} amorphous ribbon as a solder is thinner than that using physical vapor deposited Be. Among the Zr{sub 1-x} Be{sub x} amorphous binary alloys, Zr{sub 0.7} Be{sub 0.3} binary alloy is the most appropriated for joint of nuclear fuel bundle because its joint layer is smooth and thin due to low degree of Be diffusion. The microstructures of brazed layer using Ti{sub 1-y} Be{sub y} alloy, however, a solid-solution layer composed with Zr and Ti is formed toward the Zr cladding sheath and many of Zr is detected in the joint lever. 20 refs., 8 tabs., 23 figs. (author)

  12. Current Status of Lead-Free Soldering and Conductive Adhesives

    Institute of Scientific and Technical Information of China (English)

    KatsuakiSuganuma

    2003-01-01

    Lead-free soldering technology took offin the Japanese market during the year 2000, and as the year 2001-03 ushered in the 21 st century, a large number of products with lead-free soldering were already appearing on store shelves. Elsewhere, EU deliberation on the draft of the WEEE/RoHS directive finalized in February 2003 and be in force in July 2006. The course had been set for adopting lead-free solder for mounting processes of parts as well, bringing the possibility of lead-free solder mounting very close to achievement. This review will provide a view of the current state of technological progress in lead-free soldering, both in Japan and abroad, and will discuss future prospects.

  13. Solder dross removal apparatus

    Science.gov (United States)

    Webb, Winston S. (Inventor)

    1992-01-01

    An automatic dross removal apparatus (10) is disclosed for removing dross from the surface of a solder bath (22) in an automated electric component handling system. A rotatable wiper blade (14) is positioned adjacent the solder bath (22) which skims the dross off of the surface prior to the dipping of a robot conveyed component into the bath. An electronic control circuit (34) causes a motor (32) to rotate the wiper arm (14) one full rotational cycle each time a pulse is received from a robot controller (44) as a component approaches the solder bath (22).

  14. Development of lead-free solders for hybrid microcircuits

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, F.M.; Vianco, P.T.; Frear, D.R.; Robinson, D.G.

    1996-01-01

    Extensive work has been conducted by industry to develop lead-free solders for electronics applications. The driving force behind this effort is pressure to ban or tax the use of lead-bearing solders. There has been further interest to reduce the use of hazardous chemical cleaners. Lead-free soldering and low-residue, ``no clean`` assembly processing are being considered as solutions to these environmental issues. Most of the work has been directed toward commercial and military printed wiring board (PWB) technology, although similar problems confront the hybrid microcircuit (HMC) industry, where the development of lead-free HMC solders is generally lagging. Sandia National Laboratories is responsible for designing a variety of critical, high reliability hybrid components for radars. Sandia has consequently initiated a project, as part of its Environmentally Conscious Manufacturing program, to develop low-residue, lead-free soldering for HMCs. This paper discusses the progress of that work.

  15. Pb-Free Soldering Iron Temperature Controller

    Science.gov (United States)

    Hamane, Hiroto; Wajima, Kenji; Hayashi, Yoichi; Komiyama, Eiichi; Tachibana, Toshiaki; Miyazaki, Kazuyoshi

    Recently, much importance has been attached to the environmental problem. The content of two directives to better control the management of waste electronic equipment was approved. The two directives are the Waste from Electrical and Electronic Equipment (WEEE) and the Restriction of Hazardous Substances (RoHS). These set phase-out dates for the use of lead materials contained in electronic products. Increasingly, attention is focusing on the potential use of Pb-free soldering in electronics manufacturing. It should be noted that many of the current solding irons are not suitable for Pb-free technology, due to the inferior wetting ability of Pb-free alloys compared with SnPb solder pastes. This paper presents a Pb-free soldering iron temperature controller using an embedded micro-processor with a low memory capacity.

  16. Nanocopper Based Solder-Free Electronic Assembly

    Science.gov (United States)

    Schnabl, K.; Wentlent, L.; Mootoo, K.; Khasawneh, S.; Zinn, A. A.; Beddow, J.; Hauptfleisch, E.; Blass, D.; Borgesen, P.

    2014-12-01

    CuantumFuse nano copper material has been used to assemble functional LED test boards and a small camera board with a 48 pad CMOS sensor quad-flat no-lead chip and a 10 in flexible electronics demo. Drop-in replacement of solder, by use of stencil printing and standard surface mount technology equipment, has been demonstrated. Applications in space and commercial systems are currently under consideration. The stable copper-nanoparticle paste has been examined and characterized by scanning electron microscopy and high-resolution transmission electron microscopy; this has shown that the joints are nanocrystalline but with substantial porosity. Assessment of reliability is expected to be complicated by this and by the effects of thermal and strain-enhanced coarsening of pores. Strength, creep, and fatigue properties were measured and results are discussed with reference to our understanding of solder reliability to assess the potential of this nano-copper based solder alternative.

  17. Low temperature aluminum soldering analysis

    Energy Technology Data Exchange (ETDEWEB)

    Peterkort, W.G.

    1976-09-01

    The investigation of low temperature aluminum soldering included the collection of spread factor and dihedral angle data for several solder alloys and a study of flux effects on aluminum. Selected solders were subjected to environmental tests and evaluated on the basis of tensile strength, joint resistance, visual appearance, and metallurgical analysis. A production line method for determining adequate flux removal was developed.

  18. 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.

  19. Research Progress in Solderable Black Pad of Electroless Nickel/Immersion Gold

    Institute of Scientific and Technical Information of China (English)

    Liu Haiping; Li Ning; Bi Sifu; Li Deyu

    2007-01-01

    Electroless nickel/immersion gold (ENIG) technology is widely used as one of the surface final finish for electronics packaging substrate and printed circuit board (PCB), providing a protective, conductive and solderable surface. However, there is a solder joint interfacial brittle fracture (or solderability failure) of using the ENIG coating. The characteristics and the application of ENIG technology were narrated in this paper. The research progress on the solderability failure of ENIG was introduced. The mechanism of "black pad" and the possible measure of eliminating or alleviating the "black pad" were also introduced. The development direction and market prospects of ENIG were prospected.

  20. 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.

  1. SMT of Latvian, Lithuanian and Estonian languages: a comparative study

    NARCIS (Netherlands)

    M. Khalilov; L. Pretkalniņa; N. Kuvaldina; V. Pereseina

    2010-01-01

    This paper is an attempt to discover the main challenges in working with Baltic and Estonian languages, and to identify the most significant sources of errors generated by a SMT system trained on large-vocabulary parallel corpora from legislative domain. An immense distinction between Latvian/Lithua

  2. Studies on in situ particulate reinforced tin-silver composite solders relevant to thermomechanical fatigue issues

    Science.gov (United States)

    Choi, Sunglak

    2001-07-01

    Global pressure based on environmental and health concerns regarding the use of Pb-bearing solder has forced the electronics industry to develop Pb-free alternative solders. Eutectic Sn-Ag solder has received much attention as a potential Pb-free candidate to replace Sn-Pb solder. Since introduction of surface mount technology, packaging density increased and the electronic devices became smaller. As a result, solders in electronic modules are forced to function as a mechanical connection as well as electrical contact. Solders are also exposed to very harsh service conditions such as automotive under-the-hood and aerospace applications. Solder joints experience thermomechanical fatigue, i.e. interaction of fatigue and creep, during thermal cycling due to temperature fluctuation in service conditions. Microstructural study on thermomechanical fatigue of the actual eutectic Sn-Ag and Sn-4Ag-0.5Cu solder joints was performed to better understand deformation and damage accumulation occurring during service. Incorporation of reinforcements has been pursued to improve the mechanical and particularly thermomechanical behavior of solders, and their service temperature capability. In-situ Sn-Ag composite solders were developed by incorporating Cu 6Sn5, Ni3Sn4, and FeSn2 particulate reinforcements in the eutectic Sn-Ag solder in an effort to enhance thermomechanical fatigue resistance. In-situ composite solders were investigated on the growth of interfacial intermetallic layer between solder and Cu substrate growth and creep properties. Solder joints exhibited significant deformation and damage on free surface and interior regions during thermomechanical fatigue. Cracks initiated on the free surface of the solder joints and propagated toward interior regions near the substrate of the solder joint. Crack grew along Sn grain boundaries by grain boundary sliding. There was significant residual stress within the solder joint causing more damage. Presence of small amount of Cu

  3. 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 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...... bonds were consistently found to be mechanically stronger than the carbon nanotubes....

  4. Capillary flow solder wettability test

    Energy Technology Data Exchange (ETDEWEB)

    Vianco, P.T.; Rejent, J.A.

    1996-01-01

    A test procedure was developed to assess the capillary flow wettability of solders inside of a confined geometry. The test geometry was comprised of two parallel plates with a controlled gap of constant thickness (0.008 cm, 0.018 cm, 0.025 cm, and 0.038 cm). Capillary flow was assessed by: (1) the meniscus or capillary rise of the solder within the gap, (2) the extent of void formation in the gap, and (3) the time-dependence of the risen solder film. Tests were performed with the lead-free solders.

  5. TRSTR: A Fault- Tolerant Microprocessor Architecture Based on SMT

    Institute of Scientific and Technical Information of China (English)

    YANG Hua; CUI Gang; YANG Xiao-zong

    2005-01-01

    Based on Simultaneous Multithreading (SMT),we propose a fault-tolerant scheme called Tri-modular Redundantly and Simultaneously Threaded processor with Recovery (TRSTR). TRSTR features as following: First, we introduce an arbitrator context into the conventional SRT (Simultaneous and Redundantly Threaded), which acts as an arbitrator when results from the other two contexts disagree, or acts as an ordinary thread generally, thus making full use of SMT' s parallelism. Second, we append reconfigurable feature to sphere of replication in SRT, making it more flexible for changing demands and situations. Third, TRSTR has two working modes: Tri-Simultaneous with Voting (TSV) and Dual-Simultaneous with Arbitrator (DSA), which can switch at will. Finally, in addition to transient-fault coverage,TRSTR has on-line self-checking and self-recovering abilities,so as to shield off some permanent faults and reconfigure itself without stopping the crucial job, improving its reliability and availability.

  6. Environmentally friendly solders 3-4 beyond Pb-based systems

    Institute of Scientific and Technical Information of China (English)

    GAO Yuan; LIU Peng; GUO Fu; XIA Zhidong; LEI Yongping; SHI Yaowu

    2006-01-01

    Based on environmental considerations, global economic pressures, enacted by legislations in several countries, have warranted the elimination of lead from solders used in electronic applications.Sn3.5Ag, SnAgCu, and Sn0.7Cu have emerged among various lead-free candidates as the most promising solder alloys to be utilized in microelectronic industries.However, with the vast development and miniaturization of modern electronic packaging, new requirements such as superior service capabilities have been posed on lead-free solders.In order to improve the comprehensive property of the solder alloys, two possible approaches were adopted in the current research and new materials developed were patented.One approach was involved with the addition of alloying elements to make new ternary or quaternary solder alloys.Proper addition of rare earth element such as La and Ce have rendered solder alloys with improved mechanical properties, especially creep rupture lives of their joints.Another approach, the composite approach, was developed mainly to improve the service temperature capability of the solder alloys.Composite solders fabricated by mechanically incorporating various reinforcement particles to the solder paste have again exhibited enhanced properties without altering the existing processing characteristics.The recent progress and research efforts carried out on lead-free solder materials in Beijing University of Technology were reported.The effects of rare earth addition on the microstructure, processing properties, and mechanical properties were presented.The behaviors of various Sn-3.5Ag based composite solders were also explicated in terms of the roles of reinforcement particles on intermetallic growth, steady-state creep rate, the onset of tertiary creep, as well as the overall creep deformation in the solder joints.Thermomechanical fatigue (TMF) behavior of the solder alloys and composite solders were investigated with different parameters such as ramp rate

  7. ased on the SMT technology pad of printed circuit board design%基于表面贴装工艺技术的印制板焊盘设计

    Institute of Scientific and Technical Information of China (English)

    张建碧

    2012-01-01

    伴随表面贴装技术的广泛运用,印刷电路板设计工艺变得越来越重要,焊盘设计要求也变得越来越高。本文针对焊盘设计存在的缺陷加以归纳并给出了较详细的改进措施。%With surface mount technology extensive use, printed circuit board design process becomes more and more important, welding plate design requirements also becomes more and more high. This article in view of the defects of welding plate design summarized and gives a detailed measures for improvement.

  8. Development of lead-free solders for high-temperature applications

    DEFF Research Database (Denmark)

    Chidambaram, Vivek

    -temperature applications. Unfortunately, even the substitute technologies that are currently being developed cannot address several critical issues of high-temperature soldering. Therefore, further research and development of high-temperature lead-free soldering is obviously needed. It is hoped that this thesis can serve...... as a valuable source of information to those interested in environmentally conscious electronic packaging....

  9. Indium Corporation Introduces New Pb-Free VOC-Free Wave Solder Flux

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The Indium Corporation of America has introduced WF-7742 Wave Solder Flux specifically designed to meet the process demands of Pb-Free manufacturing. WF-7742 is a VOC-Free material formulated for Pb-Free wave soldering of surface-mount, mixed-technology and through-holeelectronics assemblies.

  10. 基于智能对象的 SMT 车间制造执行系统研究%A Study of SMT Workshop Manufacturing Execution System Based on Smart Objects

    Institute of Scientific and Technical Information of China (English)

    张浩; 余凤莲

    2015-01-01

    A smart-object-based manufacturing execution system for SMT workshop is proposed to realize real-time and fine management.By introducing radio frequency identification( RFID) technology and smart objects, a MES framework based on intelligent objects is given for SMT industry.Based on the introduction of the systematic deployment of RFID in the workshop, the data collection mode of the SMT shop floor is analyzed and the operation process of mistake-proofing while loading materials is described.Finally, an example of an electronic enterprise in Guangzhou illustrates the feasibility and effectiveness of the system proposed.%为了实现电子产品制造过程中对SMT车间的实时、精细化管控,本文提出了一种基于智能对象的SMT车间制造执行系统. 通过引入RFID技术与智能对象,给出了基于智能对象的SMT行业制造执行系统框架. 在介绍RFID在车间的系统化部署的基础上,详细分析了SMT车间数据采集模式,并描述了贴装过程物料防错流程. 最后以广州某电子企业为例,说明了所构建系统的可行性和有效性.

  11. Microbial leaching of waste solder for recovery of metal.

    Science.gov (United States)

    Hocheng, H; Hong, T; Jadhav, U

    2014-05-01

    This study proposes an environment-friendly bioleaching process for recovery of metals from solders. Tin-copper (Sn-Cu), tin-copper-silver (Sn-Cu-Ag), and tin-lead (Sn-Pb) solders were used in the current study. The culture supernatant of Aspergillus niger removed metals faster than the culture supernatant of Acidithiobacillus ferrooxidans. Also, the metal removal by A. niger culture supernatant is faster for Sn-Cu-Ag solder as compared to other solder types. The effect of various process parameters such as shaking speed, temperature, volume of culture supernatant, and increased solder weight on bioleaching of metals was studied. About 99 (±1.75) % metal dissolution was achieved in 60 h, at 200-rpm shaking speed, 30 °C temperature, and by using 100-ml A. niger culture supernatant. An optimum solder weight for bioleaching was found to be 5 g/l. Addition of sodium hydroxide (NaOH) and sodium chloride (NaCl) in the bioleached solution from Sn-Cu-Ag precipitated tin (85 ± 0.35 %) and silver (80 ± 0.08 %), respectively. Passing of hydrogen sulfide (H2S) gas at pH 8.1 selectively precipitated lead (57.18 ± 0.13 %) from the Sn-Pb bioleached solution. The proposed innovative bioleaching process provides an alternative technology for recycling waste solders to conserve resources and protect environment.

  12. Optical Measurement System for Motion Characterization of Surface Mount Technology

    Institute of Scientific and Technical Information of China (English)

    LI Song; AN Bing; ZHANG Tong-jun; XIE Yong-jun

    2006-01-01

    Advanced testing methods for the dynamics of mechanical microdevices are necessary to develop reliable,marketable microelectromechanical systems. A system for measuring the nanometer motions of microscopic structures has been demonstrated. Stop-action images of a target have been obtained with computer microvision,microscopic interferometry,and stroboscopic illuminator. It can be developed for measuring the in-plane-rigid-body motions,surface shapes,out-of-plane motions and deformations of microstructures. A new algorithm of sub-pixel step length correlation template matching is proposed to extract the in-plane displacement from vision images. Hariharan five-step phase-shift interferometry algorithm and unwrapping algorithms are adopted to measure the out-of-plane motions. It is demonstrated that the system can measure the motions of solder wetting in surface mount technology(SMT).

  13. Soldering Formalism Theory and Applications

    CERN Document Server

    Wotzasek, C

    1998-01-01

    The soldering mechanism is a new technique to work with distinct manifestations of dualities that incorporates interference effects, leading to new physical results that includes quantum contributions. This approach was used to investigate the cases of electromagnetic dualities, and $D\\geq 2$ bosonization. In the former context this technique is applied for the quantum mechanical harmonic oscillator, the scalar field theory in two dimensions and the Maxwell theory in four dimensions. The soldered actions in any dimension leads to a master action which is duality invariant under a much bigger set of symmetries. The effects of coupling to gravity are also elaborated. In the later context, a technique is developed that solders the dual aspects of some symmetry following from the bosonisation of two distinct fermionic models, leading to new results which cannot be otherwise obtained. Exploiting this technique, the two dimensional chiral determinants with opposite chirality are soldered to reproduce either the usu...

  14. Active soft solder deposition by magnetron-sputter-ion-plating (MSIP)-PVD-process

    Energy Technology Data Exchange (ETDEWEB)

    Lugscheider, E.; Bobzin, K.; Erdle, A

    2004-01-30

    In different technical areas micro electro mechanical systems (M.E.M.S.), e.g. micro pumps, micro sensors, actuators and micro dosage systems are in use today. The components of these M.E.M.S. consist of various materials, which have to be joined. To join materials like ceramics, plastics or metals to a hybrid M.E.M.S., established joining technologies have to be adjusted. For the assembling and mounting of temperature sensible micro components, a low temperature joining process, e.g. transient liquid phase (TLP) bonding or an active soft soldering process can be performed. In this article the deposition of a low melting active soft solder by magnetron-sputter (MS)-PVD deposition with an active substrate cooling will be presented. The substrate temperatures were set and controlled by an additional cooling unit, which was integrated into the sputtering facility. In the performed experiments a substrate temperature range from -40 to +20 deg. C was investigated. The effects of these different substrate temperatures to the microstructure and the soldering suitability of the solder system were investigated by scanning electron microscopy (SEM), nanoindentation and soldering tests. The chemical composition of the deposited solder systems was examined by glow discharge optical spectroscopy (GDOS)-analysis. As a suitable substrate temperature range for deposition -10 to -20 deg. C was detected. Solder systems deposited in this temperature range showed good solder abilities.

  15. Assessment of circuit board surface finishes for electronic assembly with lead-free solders

    Energy Technology Data Exchange (ETDEWEB)

    Ray, U.; Artaki, I.; Finley, D.W.; Wenger, G.M. [Bell Labs., Princeton, NJ (United States). Lucent Technologies; Pan, T.; Blair, H.D.; Nicholson, J.M. [Ford Motor Co., Dearborn, MI (United States); Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States)

    1996-10-01

    The suitability of various metallic printed wiring board surface finishes was assessed for new technology applications that incorporate assembly with Lead-free solders. The manufacture of a lead-free product necessitates elimination of lead (Pb) from the solder, the circuit board as well as the component lead termination. It is critical however for the selected interconnect Pb-free solder and the corresponding printed wiring board (PWB) and component lead finishes to be mutually compatible. Baseline compatibility of select Pb-free solders with Pb containing PWB surface finish and components was assessed. This was followed by examining the compatibility of the commercially available CASTIN{trademark} (SnAgCuSb) Pb-free solder with a series of PWB metallic finishes: Ni/Au, Ni/Pd, and Pd/Cu. The compatibility was assessed with respect to assembly performance, solder joint integrity and long term attachment reliability. Solder joint integrity and mechanical behavior of representative 50 mil pitch 20I/O SOICs was determined before and after thermal stress. Mechanical pull test studies demonstrated that the strength of SnAgCuSb solder interconnections is notably greater than that of SnPb interconnections.

  16. Development of alternatives to lead-bearing solders

    Energy Technology Data Exchange (ETDEWEB)

    Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States)

    1993-07-01

    Soldering technology, using tin-lead alloys has had a significant role in the packaging of highly functional, low cost electronic devices. The elimination of lead from all manufactured products, whether through legislation or tax incentives, will impact the electronics community which uses lead-containing solders. In response to these proposed measures, the National Center for Manufacturing Sciences has established a multi-year program involving participants from industry, academia, and the national laboratories with the objective to identify potential replacements for lead-bearing solders. Selection of candidate alloys is based upon the analysis of materials properties, manufacturability, modeling codes for reliability prediction, as well as toxicological properties and resource availability, data developed in the program.

  17. Materials chemistry. Composition-matched molecular "solders" for semiconductors.

    Science.gov (United States)

    Dolzhnikov, Dmitriy S; Zhang, Hao; Jang, Jaeyoung; Son, Jae Sung; Panthani, Matthew G; Shibata, Tomohiro; Chattopadhyay, Soma; Talapin, Dmitri V

    2015-01-23

    We propose a general strategy to synthesize largely unexplored soluble chalcogenidometallates of cadmium, lead, and bismuth. These compounds can be used as "solders" for semiconductors widely used in photovoltaics and thermoelectrics. The addition of solder helped to bond crystal surfaces and link nano- or mesoscale particles together. For example, CdSe nanocrystals with Na2Cd2Se3 solder was used as a soluble precursor for CdSe films with electron mobilities exceeding 300 square centimeters per volt-second. CdTe, PbTe, and Bi2Te3 powders were molded into various shapes in the presence of a small additive of composition-matched chalcogenidometallate or chalcogel, thus opening new design spaces for semiconductor technologies.

  18. English-Latvian SMT: the challenge of translating into a free word order language

    NARCIS (Netherlands)

    Khalilov, M.; Fonollosa, J.A.R.; Skadiņa, I.; Brālītis, E.; Pretkalniņa, L.

    2010-01-01

    This paper presents a comparative study of two approaches to statistical machine translation (SMT) and their application to a task of English-to-Latvian translation, which is still an open research line in the field of automatic translation. We consider a state-of-the-art phrase-based SMT and an alt

  19. OpenGL在SMT焊点中的应用%The Application of OpenGL in SMT Solder Point

    Institute of Scientific and Technical Information of China (English)

    徐剑飞; 周德俭; 黄春跃

    2006-01-01

    为检测SMT焊点的质量,提取焊点质量信息,研究了利用光学手段实测的SMT焊点的三维重建和显示技术,并且运用Visual C#.Net和OpenGL编制了一套软件.该软件可以利用SMT焊点的二维图像,通过三维重构算法计算出SMT焊点的表面高度离散点的数据集,即离散点云.对离散点云进行排序重组和三角网格化后,运用OpenGL 对三角网格进行消隐,设定法线、光照、材质和贴图的处理,重建SMT焊点的表面,由此获得SMT焊点的三维信息,利于分析焊点的质量信息.

  20. Solid/hollow, soldered/cast, morphology/technology. The Castro technological domain system through the torcs with double moulding ends

    Directory of Open Access Journals (Sweden)

    Armbruster, Barbara

    2000-06-01

    Full Text Available We oppose the direct observation of the artefacts and the study of the fabrication, distribution and consumption processes against the traditional typological view of the castro torcs. Technological variability defines best this particular archaeological material which forms part of the Iron Age goldwork in the northwest of the Iberian Peninsula. We forget its quality of adornment and conceptualize the object as a collective investment within a diachronic context beginning in the Final Bronze Age and extending into the Period of romanization.

    Contraponemos la observación directa de las piezas y el estudio del proceso de fabricación, distribución y consumo, a la tradicional visión tipológica de los torques cástrenos. La variabilidad tecnológica es la característica que mejor define este material arqueológico, dentro del conjunto de la orfebrería del noroeste peninsular de la Edad del Hierro. Olvidamos su carácter de adorno y conceptualizamos el objeto como una inversión colectiva dentro de un espacio temporal que se inicia en el Bronce Final y se prolonga hasta más allá de la romanización.

  1. Preliminary test results in support of integrated EPP and SMT design methods development

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanli [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jetter, Robert I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sham, T. -L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-02-09

    The proposed integrated Elastic Perfectly-Plastic (EPP) and Simplified Model Test (SMT) methodology consists of incorporating a SMT data-based approach for creep-fatigue damage evaluation into the EPP methodology to avoid using the creep-fatigue interaction diagram (the D diagram) and to minimize over-conservatism while properly accounting for localized defects and stress risers. To support the implementation of the proposed code rules and to verify their applicability, a series of thermomechanical tests have been initiated. One test concept, the Simplified Model Test (SMT), takes into account the stress and strain redistribution in real structures by including representative follow-up characteristics in the test specimen. The second test concept is the two-bar thermal ratcheting tests with cyclic loading at high temperatures using specimens representing key features of potential component designs. This report summaries the previous SMT results on Alloy 617, SS316H and SS304H and presents the recent development on SMT approach on Alloy 617. These SMT specimen data are also representative of component loading conditions and have been used as part of the verification of the proposed integrated EPP and SMT design methods development. The previous two-bar thermal ratcheting test results on Alloy 617 and SS316H are also summarized and the new results from two bar thermal ratcheting tests on SS316H at a lower temperature range are reported.

  2. Recycling of lead solder dross, Generated from PCB manufacturing

    Science.gov (United States)

    Lucheva, Biserka; Tsonev, Tsonio; Iliev, Peter

    2011-08-01

    The main purpose of this work is to analyze lead solder dross, a waste product from manufacturing of printed circuit boards by wave soldering, and to develop an effective and environmentally sound technology for its recycling. A methodology for determination of the content and chemical composition of the metal and oxide phases of the dross is developed. Two methods for recycling of lead solder dross were examined—carbothermal reduction and recycling using boron-containing substances. The influence of various factors on the metal yield was studied and the optimal parameters of the recycling process are defined. The comparison between them under the same parameters-temperature and retention time, showed that recycling of dross with a mixture of borax and boric acid in a 1:2 ratio provides higher metal yield (93%). The recycling of this hazardous waste under developed technology gets glassy slag and solder, which after correction of the chemical composition can be used again for production of PCB.

  3. Solder Joint Health Monitoring Testbed

    Science.gov (United States)

    Delaney, Michael M.; Flynn, James G.; Browder, Mark E.

    2009-01-01

    A method of monitoring the health of selected solder joints, called SJ-BIST, has been developed by Ridgetop Group Inc. under a Small Business Innovative Research (SBIR) contract. The primary goal of this research program is to test and validate this method in a flight environment using realistically seeded faults in selected solder joints. An additional objective is to gather environmental data for future development of physics-based and data-driven prognostics algorithms. A test board is being designed using a Xilinx FPGA. These boards will be tested both in flight and on the ground using a shaker table and an altitude chamber.

  4. 镀金引线SMD焊接工艺方法探讨%Soldering Method Research of SMD with Golding-plated Lead

    Institute of Scientific and Technical Information of China (English)

    杨艺峰; 车飞; 周承平; 吴夏凯

    2014-01-01

    With high reliability requirements of weapon system and improvement of the basis level of domestic electron components, more and more ceramic packaging of SMD apply to the military product. The component lead is mostly plated with gold, but the gold coating must be removed when the component is to be soldered. Compare and analyze the soldering quality of solder joints of golding-plated lead SMT components using four soldering methods, get the best soldering method for golding-plated lead components.%随着武器系统高可靠性要求的不断加强和国产电子元器件基础水平的不断提高,越来越多的陶瓷封装军用SMD开始应用于型号产品。该类器件的引线多采用镀金工艺,焊接时必须进行除金处理。用四种焊接工艺方法对镀金引脚器件焊接,对比分析器件焊点的焊接质量,得出镀金引脚器件最佳焊接工艺方法。

  5. Alloying influences on low melt temperature SnZn and SnBi solder alloys for electronic interconnections

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Guang [Stokes Laboratories, Bernal Institute, University of Limerick (Ireland); Department of Civil Engineering and Materials Science, University of Limerick (Ireland); Wilding, Ian J. [Henkel Ltd, Hemel Hempstead (United Kingdom); Collins, Maurice N., E-mail: Maurice.collins@ul.ie [Stokes Laboratories, Bernal Institute, University of Limerick (Ireland)

    2016-04-25

    Due to its commercial potential and the technological challenges associated with processing, low temperature soldering is a topic gaining widespread interest in both industry and academia in the application space of consumer and “throw away” electronics. This review focuses on the latest metallurgical alloys, tin zinc (Sn–Zn) and tin bismuth (Sn–Bi), for lower temperature processed electronic interconnections. The fundamentals of solder paste production and flux development for these highly surface active metallic powders are introduced. Intermetallic compounds that underpin low temperature solder joint production and reliability are discussed. The influence of alloying on these alloys is described in terms of critical microstructural changes, mechanical properties and reliability. The review concludes with an outlook for next generation electronic interconnect materials. - Highlights: • Review of the latest advances in Sn–Zn and Sn–Bi solder alloys. • Technological developments underpinning low temperature soldering. • Micro alloying influences on next generation interconnect materials.

  6. Porosity in collapsible Ball Grid Array solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, C.A. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering]|[Lawrence Berkeley National Lab., Berkeley, CA (United States). Materials Science Div.

    1998-05-01

    Ball Grid Array (BGA) technology has taken off in recent years due to the increased need for high interconnect density. Opposite to all the advantages BGA packages offer, porosity in collapsible BGA solder joints is often a major concern in the reliability of such packages. The effect of pores on the strength of collapsible BGA solder-joints was studied by manufacturing samples with different degrees of porosity and testing them under a shear load. It was found that the shear strength of the solder joints decreased in a linear fashion with increasing porosity. Failure occurred by internal necking of the interpore matrix. It was confirmed that entrapment of flux residues leads to porosity by manufacturing fluxless samples in a specially made furnace, and comparing them with samples assembled using flux. Also, contamination of Au electrodeposits (in substrate metallization) was determined to cause significant porosity. It was found that hard-Au (Co hardened Au) electrodeposits produce high degrees of porosity even in the absence of flux. Finally, increasing the time the solder spends in the molten state was proven to successfully decrease porosity.

  7. Fundamentals of wetting and spreading with emphasis on soldering

    Energy Technology Data Exchange (ETDEWEB)

    Yost, F.G.

    1991-01-01

    Soldering is often referred to as a mature technology whose fundamentals were established long ago. Yet a multitude of soldering problems persist, not the least of which are related to the wetting and spreading of solder. The Buff-Goodrich approach to thermodynamics of capillarity is utilized in a review of basic wetting principles. These thermodynamics allow a very compact formulation of capillary phenomena which is used to calculate various meniscus shapes and wetting forces. These shapes and forces lend themselves to experimental techniques, such as the sessile drop and the Wilhelmy plate, for measuring useful surface and interfacial energies. The familiar equations of Young, Wilhelmy, and Neumann are all derived with this approach. The force-energy duality of surface energy is discussed and the force method is developed and used to derive the Herring relations for anisotropic surfaces. The importance of contact angle hysteresis which results from surface roughness and chemical inhomogeneity is presented and Young's equation is modified to reflect these ever present effects. Finally, an analysis of wetting with simultaneous metallurigical reaction is given and used to discuss solder wetting phenomena. 60 refs., 13 figs.

  8. Study on Sn-Zn Solder Used in Cu-Al Soldering%用于铜铝焊接的锡锌焊料研究

    Institute of Scientific and Technical Information of China (English)

    倪广春; 张浩; 韩敏

    2013-01-01

    Lead-free electronic products led the development of lead-free solder technology. Taking cost factors into account, some copper material has been replaced by aluminum material. When ordinary Sn-Cu and Sn-Ag-Cu solder are used in soldering of Cu-Al, there is the electrochemical corrosion problems. So Sn-Zn solder is used for Cu-Al soldering. However, the joints of Sn-Zn solder are brittle and easy to crack. Focus on problems in Cu-Al soldering joint of electrical and electronic devices, put forward Sn-Zn-X alloy soldering materials, did a large number of experiments, and achieved good results.%电子产品无铅化的推广带动了无铅焊料技术的发展,考虑到成本因素,部分铜材已被铝材取代。普通的锡铜系和锡银铜系焊料在铜铝焊接时,存在电化学腐蚀问题,因此多用锡锌焊料进行焊接。但锡锌焊料的焊点脆,存在易开裂的问题。针对电工电子器件铜铝焊接点存在的问题,提出了Sn一Zn一X多元合金焊接材料,并做了大量实验,取得很好的效果。

  9. 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

    For microelectronics and especially for upcoming new packaging technologies in micromechanics and photonics fluxless, reliable and economic soldering technologies are needed. In this article, we consequently focus on the oxidation and reduction kinetics of three commonly used eutectic solder allo...... and reflowed AuSn(80/20) and SnPb(60/40) after the introduction of H2...

  10. Effects of rapid solidification on the microstructure and microhardness of a lead-free Sn-3.5Ag solder

    Institute of Scientific and Technical Information of China (English)

    SHEN Jun; LIU Yongchang; Han Yajing; GAO Houxiu

    2006-01-01

    A lead-free Sn-3.5Ag solder was prepared by rapid solidification technology. The high solidification rate, obtained by rapid cooling, promotes nucleation, and suppresses the growth of Ag3Sn intermetallic compounds (IMCs) in Ag-rich zone, yielding fine Ag3Sn nanoparticulates with spherical morphology in the matrix of the solder. The large amount of tough homogeneously-dispersed IMCs helps to improve the surface area per unit volume and obstructs the dislocation lines passing through the solder, which fits with the dispersion-strengthening theory. Hence, the rapidly-solidified Sn-3.5Ag solder exhibits a higher microhardness when compared with a slowly-solidified Sn-3.5Ag solder.

  11. 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...

  12. Die Soldering in Aluminium Die Casting

    Energy Technology Data Exchange (ETDEWEB)

    Han, Q.; Kenik, E.A.; Viswanathan, S.

    2000-03-15

    Two types of tests, dipping tests and dip-coating tests were carried out on small steel cylinders using pure aluminum and 380 alloy to investigate the mechanism of die soldering during aluminum die casting. Optical and scanning electron microscopy were used to study the morphology and composition of the phases formed during soldering. A soldering mechanism is postulated based on experimental observations. A soldering critical temperature is postulated at which iron begins to react with aluminum to form an aluminum-rich liquid phase and solid intermetallic compounds. When the temperature at the die surface is higher than this critical temperature, the aluminum-rich phase is liquid and joins the die with the casting during the subsequent solidification. The paper discusses the mechanism of soldering for the case of pure aluminum and 380 alloy casting in a steel mold, the factors that promote soldering, and the strength of the bond formed when soldering occurs. conditions, an aluminum-rich soldering layer may also form over the intermetallic layer. Although a significant amount of research has been conducted on the nature of these intermetallics, little is known about the conditions under which soldering occurs.

  13. Study on laser and hot air reflow soldering of PBGA solder ball

    Institute of Scientific and Technical Information of China (English)

    田艳红; 王春青

    2002-01-01

    Laser and hot air reflow soldering of PBGA solder ball was investigated. Experimental results showed that surface quality and shear strength of solder bump reflowed by laser was superior than the solder bump by hot air, and the microstructure within the solder bump reflowed by laser was much finer. Analysis on interfacial reaction showed that eutectic solder reacted with Au/Ni/Cu pad shortly after the solder was melted. Interface of solder bump reflowed by laser consists of a continuous AuSn4 layer and remnant Au element. Needle-like AuSn4 grew sidewise from interface, and then spread out to the entire interface region. A thin layer of Ni3Sn4 intermetallic compound was found at the interface of solder bump reflowed by hot air, and AuSn4 particles distributed within the whole solder bump randomly. The combination effect of the continuous AuSn4 layer and finer eutectic microstructure contributes to the higher shear strength of solder bump reflowed by laser.

  14. Mechanical properties of Pb-free solder alloys on thick film hybrid microcircuits

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, C.L.; Vianco, P.T.; Rejent, J.A.; Hosking, F.M.

    1998-03-10

    The technology drivers of the electronics industry continue to be systems miniaturization and reliability, in addition to addressing a variety of important environmental issues. Although the Sn-Pb eutectic alloy is widely used as a joining material in the electronics industry, it has drawn environmental concern due to its Pb content. The solder acts both as an electrical and mechanical connection within the different packaging levels in an electronic device. New Pb-free solders are being developed at Sandia National Laboratories. The alloys are based on the Sn-Ag alloy, having Bi and Au additions. Prototype hybrid microcircuit (HMC) test vehicles have been assembled to evaluate Pb-free solders for Au-Pt-Pd thick film soldering. The test components consist of a variety of dummy chip capacitors and leadless ceramic chip carriers (LCCC`s). The mechanical properties of the joints were evaluated. The reflow profiles and the solid state intermetallic formation reaction will also be presented. Improved solder joint manufacturability and increased fatigue resistance solder alloys are the goals of these materials.

  15. 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.

  16. 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.

  17. WETTABILITY STUDIES OF LEAD-FREE SOLDERS

    African Journals Online (AJOL)

    2012-03-01

    Mar 1, 2012 ... Based on this, a wettability test using copper grid was conducted on the solder alloys produced. The result shows that wetting time varied from 4 seconds to 5 seconds for the lead-free solders ... at the interfaces [4]. This study ...

  18. Nano-soldering to single atomic layer

    Science.gov (United States)

    Girit, Caglar O.; Zettl, Alexander K.

    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.

  19. Weak signal detection in hyperspectral imagery using sparse matrix transform (SMT) covariance estimation

    Energy Technology Data Exchange (ETDEWEB)

    Theiler, James P [Los Alamos National Laboratory; Cao, Guangzhi [PURDUE UNIV; Bouman, Charles A [PURDUE UNIV

    2009-01-01

    Many detection algorithms in hyperspectral image analysis, from well-characterized gaseous and solid targets to deliberately uncharacterized anomalies and anomlous changes, depend on accurately estimating the covariance matrix of the background. In practice, the background covariance is estimated from samples in the image, and imprecision in this estimate can lead to a loss of detection power. In this paper, we describe the sparse matrix transform (SMT) and investigate its utility for estimating the covariance matrix from a limited number of samples. The SMT is formed by a product of pairwise coordinate (Givens) rotations, which can be efficiently estimated using greedy optimization. Experiments on hyperspectral data show that the estimate accurately reproduces even small eigenvalues and eigenvectors. In particular, we find that using the SMT to estimate the covariance matrix used in the adaptive matched filter leads to consistently higher signal-to-noise ratios.

  20. Low cycle fatigue of lead free solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Schemmann, Lars; Wedi, Andre; Baither, Dietmar; Schmitz, Guido [Institut fuer Materialphysik, Westf. Wilhelms-Universitaet, Muenster (Germany)

    2011-07-01

    Presently solders containing lead are banned from consumer electronics. Important alternatives are the Sn-Ag-Cu (SAC) solders and solders containing antimony. This work studies the isothermal low cycle fatigue properties of SAC solders and the SnSb(8) solder. For the experiments, model solder joints were produced and used. They consist of two pure copper plates joined together by a circular disk of solder. Low cycle fatigue experiments were done under displacement control. Furthermore hardness was tested by a micro indenter. In order to find an explanation for the different lifetimes of the solders, several micro structural investigations were performed. For this we used transmission and scanning electron microscopy as well as optical microscopy. The measured data showed a strong relation between lifetime and hardness of the solder alloy. We also found, that the type of solder influences the crack propagation.

  1. Effects of bismuth on growth of intermetallic compounds in Sn-Ag-Cu Pb-free solder joints

    Institute of Scientific and Technical Information of China (English)

    LI Guo-yuan; SHI Xun-qing

    2006-01-01

    The effects of Bi addition on the growth of intermetallic compound (IMC) formation in Sn-3.8Ag-0.7Cu solder joints were investigated. The test samples were prepared by conventional surface mounting technology. To investigate the element diffusion and the growth kinetics of intermetallics formation in solder joint,isothermal aging test was performed at temperatures of 100,150,and 190 ℃,respectively. The optical microscope (OM) and scanning electron microscope (SEM) were used to observe microstructure evolution of solder joint and to estimate the thickness and the grain size of the intermetallic layers. The IMC phases were identified by energy dispersive X-ray (EDX) and X-ray diffractometer (XRD). The results clearly show that adding about 1.0% Bi in Sn-Ag-Cu solder alloy system can refine the grain size of the IMC and inhibit the excessive IMC growth in solder joints,and therefore improve the reliability of the Pb-free solder joints. Through observation of the microstructural evolution of the solder joints,the mechanism of inhibition of IMC growth due to Bi addition was proposed.

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

    Science.gov (United States)

    2005-09-01

    controlled fatigue life, likely because of increased void -nucleation via creep-fatigue interactions. Since the solder is largely under strain-controlled...to plastically deform the solder in order to break the oxide layers and eliminate some minor voids around the NiTi particles. Figure 32... Underfill Constraint Effects during Thermomechanical Cycling of Flip Chip Solder Joints,” Journal of Electronic Materials, Vol. 31, No. 4, 2002

  3. FY16 Progress Report on Test Results In Support Of Integrated EPP and SMT Design Methods Development

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanli [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jetter, Robert I. [RI Jetter Consulting, Pebble Beach, CA (United States); Sham, T. -L. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-08-08

    The proposed integrated Elastic Perfectly-Plastic (EPP) and Simplified Model Test (SMT) methodology consists of incorporating an SMT data-based approach for creep-fatigue damage evaluation into the EPP methodology to avoid using the creep-fatigue interaction diagram (the D diagram) and to minimize over-conservatism while properly accounting for localized defects and stress risers. To support the implementation of the proposed code rules and to verify their applicability, a series of thermomechanical tests have been initiated. This report presents the recent test results for Type 2 SMT specimens on Alloy 617, Pressurization SMT on Alloy 617, Type 1 SMT on Gr. 91, and two-bar thermal ratcheting test results on Alloy 617 with a new thermal loading profile.

  4. Lead Ingestion Hazard in Hand Soldering Environments.

    Science.gov (United States)

    1984-05-01

    RD-Ai45 663 LEAD INGESTION HAZARD IN HAND SOLDERING ENVIRONMENTS i/i (U) NAVAL WEAPONS CENTER CHINA LAKE CA E R MONSALVE MAY 84 NWC-TP-6545...6545 Lead Ingestion Hazard in Hand Soldering Environments (JD CD I) by Elisabeth R. Monsalve a y- Safety and Security Department I MAY 1984 NAVAL...COVERED LEAD INGESTION HAZARD IN HAND SOLDERING ENVIRONMENTS A summary report 6. PERFORMING ONG. REPORT NUMBER 7. AUTHOR(q) I. CONTRACT O GRANT NUM6ERt

  5. High-precision optomechanical lens system for space applications assembled by a local soldering technique

    Science.gov (United States)

    Pleguezuelo, Pol Ribes; Koechlin, Charlie; Hornaff, Marcel; Kamm, Andreas; Beckert, Erik; Fiault, Guillaume; Eberhardt, Ramona; Tünnermann, Andreas

    2016-06-01

    Soldering using metallic solder alloys is an alternative to adhesive bonding. Laser-based soldering processes are especially well suited for the joining of optical components made of fragile and brittle materials such as glass, ceramics, and optical crystals. This is due to a localized and minimized input of thermal energy. Solderjet bumping technology has been used to assemble a lens mount breadboard using specifications and requirements found for the optical beam expander for the European Space Agency EarthCare Mission. The silica lens and a titanium barrel have been designed and assembled with this technology in order to withstand the stringent mission demands of handling high mechanical and thermal loads without losing the optical performance. Finally, a high-precision optomechanical lens mount has been assembled with minimal localized stress (<1 MPa) showing outstanding performance in terms of wave-front error and beam depolarization ratio before and after environmental tests.

  6. Comparative in vitro activities of SMT19969, a new antimicrobial agent, against 162 strains from 35 less frequently recovered intestinal Clostridium species: implications for Clostridium difficile recurrence.

    Science.gov (United States)

    Goldstein, Ellie J C; Citron, Diane M; Tyrrell, Kerin L

    2014-01-01

    We determined the comparative activity of SMT19969 (SMT) against 162 strains representing 35 well-characterized Clostridium species in clusters I to XIX and 13 Clostridium species that had no 16S rRNA match. SMT MICs ranged from 0.06 to >512 μg/ml and were not species related. SMT might have less impact on normal gut microbiota than other Clostridium difficile infection (CDI) antimicrobials.

  7. The smt-0 mutation which abolishes mating-type switching in fission yeast is a deletion

    DEFF Research Database (Denmark)

    Styrkársdóttir, U; Egel, R; Nielsen, O

    1993-01-01

    Mating-type switching in the fission yeast, S. pombe, is initiated by a DNA double-strand break (DSB) between the mat1 cassette and the H1 homology box. The mat1-cis-acting mutant, smt-0, abolishes mating-type switching and is shown here to be a 263-bp deletion. This deletion starts in the middle...

  8. Report on FY17 testing in support of integrated EPP-SMT design methods development

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanli . [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jetter, Robert I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sham, T. -L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    The goal of the proposed integrated Elastic Perfectly-Plastic (EPP) and Simplified Model Test (SMT) methodology is to incorporate a SMT data-based approach for creep-fatigue damage evaluation into the EPP methodology to avoid the separate evaluation of creep and fatigue damage and eliminate the requirement for stress classification in current methods; thus greatly simplifying evaluation of elevated temperature cyclic service. The purpose of this methodology is to minimize over-conservatism while properly accounting for localized defects and stress risers. To support the implementation of the proposed methodology and to verify the applicability of the code rules, thermomechanical tests continued in FY17. This report presents the recent test results for Type 1 SMT specimens on Alloy 617 with long hold times, pressurization SMT on Alloy 617, and two-bar thermal ratcheting test results on SS316H at the temperature range of 405 °C to 705 °C. Preliminary EPP strain range analysis on the two-bar tests are critically evaluated and compared with the experimental results.

  9. Unexpected Interactions of the Cyanobacterial Metallothionein SmtA with Uranium.

    Science.gov (United States)

    Acharya, Celin; Blindauer, Claudia A

    2016-02-15

    Molecules for remediating or recovering uranium from contaminated environmental resources are of high current interest, with protein-based ligands coming into focus recently. Metallothioneins either bind or redox-silence a range of heavy metals, conferring protection against metal stress in many organisms. Here, we report that the cyanobacterial metallothionein SmtA competes with carbonate for uranyl binding, leading to formation of heterometallic (UO2)(n)Zn4SmtA species, without thiol oxidation, zinc loss, or compromising secondary or tertiary structure of SmtA. In turn, only metalated and folded SmtA species were found to be capable of uranyl binding. (1)H NMR studies and molecular modeling identified Glu34/Asp38 and Glu12/C-terminus as likely adventitious, but surprisingly strong, bidentate binding sites. While it is unlikely that these interactions correspond to an evolved biological function of this metallothionein, their occurrence may offer new possibilities for designing novel multipurpose bacterial metallothioneins with dual ability to sequester both soft metal ions including Cu(+), Zn(2+), Cd(2+), Hg(2+), and Pb(2+) and hard, high-oxidation state heavy metals such as U(VI). The concomitant protection from the chemical toxicity of uranium may be valuable for the development of bacterial strains for bio-remediation.

  10. Modeling the diffusion of solid copper into liquid solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Rizvi, M.J. [School of Computing and Mathematical Sciences, University of Greenwich, 30 Park Row, London, SE10 9LS (United Kingdom)], E-mail: rm77@gre.ac.uk; Lu, H.; Bailey, C. [School of Computing and Mathematical Sciences, University of Greenwich, 30 Park Row, London, SE10 9LS (United Kingdom)

    2009-01-01

    During the soldering process, the copper atoms diffuse into liquid solders. The diffusion process determines integrity and the reworking possibility of a solder joint. In order to capture the diffusion scenarios of solid copper into liquid Sn-Pb and Sn-Cu solders, a computer modeling has been performed for 10 s. An analytical model has also been proposed for calculating the diffusion coefficient of copper into liquid solders. It is found that the diffusion coefficient for Sn-Pb solder is 2.74 x 10{sup -10} m{sup 2}/s and for Sn-Cu solder is 6.44 x 10{sup -9} m{sup 2}/s. The modeling results reveal that the diffusion coefficient is one of the major factors that govern the rate at which solid Cu dissolve in the molten solder. The predicted dissolved amounts of copper into solders have been validated with the help of scanning electron microscopic analysis.

  11. Soldering Chiralities; 2, Non-Abelian Case

    CERN Document Server

    Wotzasek, C

    1996-01-01

    We study the non-abelian extension of the soldering process of two chiral WZW models of opposite chiralities, resulting in a (non-chiral) WZW model living in a 2D space-time with non trivial Riemanian curvature.

  12. Shrink-Fit Solderable Inserts Seal Hermetically

    Science.gov (United States)

    Croucher, William C.

    1992-01-01

    Shrink-fit stainless-steel insert in aluminum equipment housing allows electrical connectors to be replaced by soldering, without degrading hermeticity of housing or connector. Welding could destroy electrostatic-sensitive components and harm housing and internal cables. Steel insert avoids problems because connector soldered directly to it rather than welded to housing. Seals between flange and housing, and between connector and flange resistant to leaks, even after mechanical overloading and thermal shocking.

  13. 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.

  14. Temperature versus time curves for manual and automated soldering processes

    Energy Technology Data Exchange (ETDEWEB)

    Trent, M.A.

    1978-08-01

    Temperature-versus-time curves were recorded for various electronic components during pre-tinning, hand soldering, and drag soldering operations to determine the temperature ranges encountered. The component types investigated included a wide range of electronic assemblies. The data collected has been arranged by process and will help engineers to: (1) predetermine the thermal profile to which various components are subjected during the soldering operation; (2) decide--on the basis of component heat sensitivity and the need for thermal relief--where hand soldering would be more feasible than drag soldering; and (3) determine the optimum drag solder control parameters.

  15. NCMS PWB program report surface finishes team task WBS No. 3.1.1: Phase 1, Etching Studies: Chemical etching of copper for improved solderability

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, J.O.; Guilinger, T.R.; Hosking, F.M.; Yost, F.G.; Sorensen, N.R.

    1995-06-01

    Sandia National Laboratories has established a Cooperative Research and Development Agreement with consortium members of the National Center for Manufacturing Sciences (NCMS) to develop fundamental generic technology in the area of printed wiring board materials and surface finishes. Improved solderability of copper substrates is an important component of the Sandia-NCMS program. We are investigating the effects of surface roughness on the wettability and solderability behavior of several different types of copper board finishes. In this paper, we present roughness and solderability characterizations for a variety of chemically-etched copper substrates. Initial testing on six chemical etches demonstrate that surface roughness can be greatly enhanced through chemical etching. Noticeable improvements in solder wettability were observed to accompany increases in roughness. A number of different algorithms and measures of roughness were used to gain insight into surface morphologies that lead to improved solderability.

  16. Use of organic solderability preservatives on solderability retention of copper after accelerated aging

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, C.L.; Sorensen, N.R.; Lucero, S.J.

    1997-02-01

    Organic solderability preservatives (OSP`s) have been used by the electronics industry for some time to maintain the solderability of circuit boards and components. Since solderability affects both manufacturing efficiency and product reliability, there is significant interest in maintaining good solder wettability. There is often a considerable time interval between the initial fabrication of a circuit board or component and its use at the assembly level. Parts are often stored under a variety of conditions, in many cases not well controlled. Solder wettability can deteriorate during storage, especially in harsh environments. This paper describes the ongoing efforts at Sandia National Laboratories to quantify solder watability on bare and aged copper surfaces. Benzotriazole and imidazole were applied to electronic grade copper to retard aging effects on solderability. The coupons were introduced into Sandia`s Facility for Atmospheric Corrosion Testing (FACT) to simulate aging in a typical indoor industrial environment. H{sub 2}S, NO{sub 2} and Cl{sub 2} mixed gas was introduced into the test cell and maintained at 35{degrees}C and 70% relative humidity for test periods of one day to two weeks. The OSP`s generally performed better than bare Cu, although solderability diminished with increasing exposure times.

  17. The Numerical Analysis of Strain Behavior at Solder Joint and Interface of Flip Chip Package

    Institute of Scientific and Technical Information of China (English)

    S; C; Chen; Y; C; Lin

    2002-01-01

    The flip chip package is a kind of advanced electri ca l packages. Due to the requirement of miniaturization, lower weight, higher dens ity and higher performance in the advanced electric package, it is expected that flip chip package will soon be a mainstream technology. The silicon chip is dir ectly connected to printing circuit substrate by SnPb solder joints. Also, the u nderfill, a composite of polymer and silica particles, is filled in the gap betw een the chip and substrate around the solder joint...

  18. Corrosion resistance of the soldering joint of post-soldering of palladium-based metal-ceramic alloys.

    Science.gov (United States)

    Kawada, E; Sakurai, Y; Oda, Y

    1997-05-01

    To evaluate the corrosion resistance of post soldering of metal-ceramic alloys, four commercially available palladium-system metal-ceramic alloys (Pd-Cu, Pd-Ni, Pd-Ag, and Pd-Sb systems) and two types of solder (12 k gold solder and 16 k gold solder) with different compositions and melting points were used. The corrosion resistance of the soldered joint was evaluated by anodic polarization. The electrochemical characteristics of soldered surface were measured using electrochemical equipment. Declines in corrosion resistance were not detectable with Pd-Cu, Pd-Ag and Pd-Sb types, but break down at low potential occurred with Pd-Ni type.

  19. The Lead-Free Solder Selection Method and Process Optimization Based on Design of Experiment

    Directory of Open Access Journals (Sweden)

    Wang Bing

    2013-07-01

    Full Text Available In the study, through researching the characteristic of the lead-free solder, we introduce the method of QFD (Quality Function Deployment to transform the demand of production properties and process into the technical demand of the lead-free solder, thus we could transform the demand concept of sampling into a concrete performance index. Finally we can obtain two parameters of the technological competitive power index and market competitive power index to evaluate performance of the lead-free solder through making a series of experiments. We utilize the design of experiment method to find out key parameter of process and the best collocation of parameter, which make the co planarity of tin ball descend to 149 from 178 and promote the process’s ability up to 95.2 from 85%.

  20. Damage and protection of static electricity in SMT industry%静电在SMT行业内的危害与防护

    Institute of Scientific and Technical Information of China (English)

    胡欣涛

    2013-01-01

    SMT电路板表面贴装技术是当今电路板集成制造领域内普遍使用的一项技术。静电作为一种因摩擦感应而产生的电能,会对SMT制造行业带来严重危害,尤其会对集成电路板上的SSD器件产生伤害。在SMT生产制造过程中开展针对静电产生根源的分析与研究,并对各种SSD器件按照等级特性,进行分级防护,在企业内部建立起一套完整的防护静电措施与制度。这样才能有效杜绝静电在整个生产过程中的产生与影响,保证SMT产品的质量与安全。%SMT (surface mounted technology) is a widely used technique for produing electronic circuits boards. Static electricity,an electronic energy generated through tribocharging and induction,can cause great damage to SMT industry,espe-cially to static sensitive devices(SSDs)on integrated circuits boards. In order to effectively prevent the harmful effect caused by ESD in the production,the causes of generating the static electricity in manufacturing processes are analyzed,various SSDs are protected according to their classes and properties,and the precautions and regulations are established inside the company to en-sure the quality and safety of SMT.

  1. Age-aware solder performance models : level 2 milestone completion.

    Energy Technology Data Exchange (ETDEWEB)

    Neilsen, Michael K.; Vianco, Paul Thomas; Neidigk, Matthew Aaron; Holm, Elizabeth Ann

    2010-09-01

    Legislated requirements and industry standards are replacing eutectic lead-tin (Pb-Sn) solders with lead-free (Pb-free) solders in future component designs and in replacements and retrofits. Since Pb-free solders have not yet seen service for long periods, their long-term behavior is poorly characterized. Because understanding the reliability of Pb-free solders is critical to supporting the next generation of circuit board designs, it is imperative that we develop, validate and exercise a solder lifetime model that can capture the thermomechanical response of Pb-free solder joints in stockpile components. To this end, an ASC Level 2 milestone was identified for fiscal year 2010: Milestone 3605: Utilize experimentally validated constitutive model for lead-free solder to simulate aging and reliability of solder joints in stockpile components. This report documents the completion of this milestone, including evidence that the milestone completion criteria were met and a summary of the milestone Program Review.

  2. Computer simulation of solder joint failure

    Energy Technology Data Exchange (ETDEWEB)

    Burchett, S.N.; Frear, D.R. [Sandia National Lab., Albuquerque, NM (United States); Rashid, M.M. [Univ. of California, Davis, CA (United States)

    1997-04-01

    The thermomechanical fatigue failure of solder joints is increasingly becoming an important reliability issue for electronic packages. The purpose of this Laboratory Directed Research and Development (LDRD) project was to develop computational tools for simulating the behavior of solder joints under strain and temperature cycling, taking into account the microstructural heterogeneities that exist in as-solidified near eutectic Sn-Pb joints, as well as subsequent microstructural evolution. The authors present two computational constitutive models, a two-phase model and a single-phase model, that were developed to predict the behavior of near eutectic Sn-Pb solder joints under fatigue conditions. Unique metallurgical tests provide the fundamental input for the constitutive relations. The two-phase model mathematically predicts the heterogeneous coarsening behavior of near eutectic Sn-Pb solder. The finite element simulations with this model agree qualitatively with experimental thermomechanical fatigue tests. The simulations show that the presence of an initial heterogeneity in the solder microstructure could significantly degrade the fatigue lifetime. The single-phase model was developed to predict solder joint behavior using materials data for constitutive relation constants that could be determined through straightforward metallurgical experiments. Special thermomechanical fatigue tests were developed to give fundamental materials input to the models, and an in situ SEM thermomechanical fatigue test system was developed to characterize microstructural evolution and the mechanical behavior of solder joints during the test. A shear/torsion test sample was developed to impose strain in two different orientations. Materials constants were derived from these tests. The simulation results from the two-phase model showed good fit to the experimental test results.

  3. [Clinical study of SMT-Ⅱ video laryngoscope with difficult airway intubation in emergency department].

    Science.gov (United States)

    Yu, J H; Wang, Y

    2017-07-01

    Objective: To observe the clinical feasibility and security of SMT-Ⅱ video laryngoscope in difficult airway intubation in emergency department. Methods: This study took 90 adults with difficult airway who were admitted to the rescue room of Jingxi court of Beijing Chao-Yang Hospital, Capital Medical University from January 2015 to December 2016.The patients were randomly divided into 2 groups(SMT-Ⅱ video laryngoscope group: n=45, Macintosh direct laryngoscope group: n=45), which were treated with endotracheal intubation and ventilator assisted ventilation.The evaluation of difficult mask ventilation(DMV) independent risk factor score, Wlison score, Cormack-Lehane grade, mouth opening, thyromental distance, visualization of the glottis, time for laryngoscopy, time for tracheal intubation, first-pass success rate of intubation, complications, mean arterial pressure(MAP) and heart rate(HR) before induction, after laryngoscopy, after induction, after intubation 5 minutes, 10 minutes were recorded.ANOVA, t-test, Chi-square test was used to analyze differences data, respectively. Results: There was no significant difference between the two groups in terms of gender, age, height, weight and other general data, mouth opening, DMV independent risk factor score, Wlison score, and thyromental distance(χ(2)=0.045, t=-0.367, t=0.684, t=0.511, t=0.330, t=-0.724, t=1.219, t=1.034, all P>0.05). A Cormack-Lehane grade Ⅰ or Ⅱ view were 44 cases in SMT-Ⅱ video laryngoscope group and 14 cases in Macintosh direct laryngoscope group. It significantly improved with the use of SMT- Ⅱ video laryngoscope, compared with Macintosh direct laryngoscope(χ(2)=52.096, P<0.01). The time to best view was shorter in SMT-Ⅱ video laryngoscope group compared to that in Macintosh direct laryngoscope group with (15.0±1.0) seconds vs. (24.2±3.4) seconds(t=-26.319, P<0.05). The tube passage time was shorter with SMT-Ⅱ video laryngoscope (31.6±4.3) seconds vs. (12.7±0.9) seconds(t=-21

  4. Influence of nickel-phosphorus surface roughness on wettability and pores formation in solder joints for high power electronic applications

    Science.gov (United States)

    Vivet, L.; Joudrier, A.-L.; Tan, K.-L.; Morelle, J.-M.; Etcheberry, A.; Chalumeau, L.

    2013-12-01

    Electroless nickel-high-phosphorus Ni-P plating is used as substrate coating in the electronic component technology. The ability to minimize pores formation in solder joints and the wettability of the Ni-P layer remain points of investigation. The qualities and the control of the physical and chemical properties of the deposits are essential for the reliability of the products. In this contribution it has been measured how a controlled change of one property of the Ni-P surface, its average roughness, changes the wettability of this surface before soldering completion, at ambient temperature and under ambient air, and how it contribute to change the amount and size of pores inside solder joints, after soldering completion. Before all, observations of the Ni-P surfaces using scanning electron microscopy have been achieved. Then the wettability has been measured through the determination of both the disperse and the polar fractions of the substrate surface tension, based on the measurements of the wetting angle for droplets of four different liquids, under ambient air and at room temperature (classical sessile drop technique). Finally the X-ray micro-radiography measurements of both the area fraction of pores and the size of the largest pore inside the solder joint of dice laser soldered on the studied substrate, using high melting temperature solder (300 °C, PbSnAg) have been achieved. This study clearly demonstrates that both the ability to minimize pores formation in solder joints and the wettability under ambient conditions of the Ni-P substrate decrease and become more variable when its average roughness increases. These effects can be explained considering the Cassie-Baxter model for rough surface wetting behaviour, completed by the model of heterogeneous nucleation and growth for gas bubbles inside a liquid.

  5. Influence of nickel–phosphorus surface roughness on wettability and pores formation in solder joints for high power electronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Vivet, L., E-mail: laurent.vivet@valeo.com [Valeo, Group Electronic Expertise and Development Services, 2 rue André Boulle, 94046 Créteil (France); Joudrier, A.-L. [Institut Lavoisier de Versailles, UMR CNRS 8180, 45 Avenue des Etats-Unis, 78035 Versailles (France); Tan, K.-L.; Morelle, J.-M. [Valeo, Group Electronic Expertise and Development Services, 2 rue André Boulle, 94046 Créteil (France); Etcheberry, A. [Institut Lavoisier de Versailles, UMR CNRS 8180, 45 Avenue des Etats-Unis, 78035 Versailles (France); Chalumeau, L. [Egide, Site industriel du Sactar, 85500 Bollène (France)

    2013-12-15

    Electroless nickel-high-phosphorus Ni–P plating is used as substrate coating in the electronic component technology. The ability to minimize pores formation in solder joints and the wettability of the Ni–P layer remain points of investigation. The qualities and the control of the physical and chemical properties of the deposits are essential for the reliability of the products. In this contribution it has been measured how a controlled change of one property of the Ni–P surface, its average roughness, changes the wettability of this surface before soldering completion, at ambient temperature and under ambient air, and how it contribute to change the amount and size of pores inside solder joints, after soldering completion. Before all, observations of the Ni–P surfaces using scanning electron microscopy have been achieved. Then the wettability has been measured through the determination of both the disperse and the polar fractions of the substrate surface tension, based on the measurements of the wetting angle for droplets of four different liquids, under ambient air and at room temperature (classical sessile drop technique). Finally the X-ray micro-radiography measurements of both the area fraction of pores and the size of the largest pore inside the solder joint of dice laser soldered on the studied substrate, using high melting temperature solder (300 °C, PbSnAg) have been achieved. This study clearly demonstrates that both the ability to minimize pores formation in solder joints and the wettability under ambient conditions of the Ni–P substrate decrease and become more variable when its average roughness increases. These effects can be explained considering the Cassie–Baxter model for rough surface wetting behaviour, completed by the model of heterogeneous nucleation and growth for gas bubbles inside a liquid.

  6. 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[...

  7. 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.

  8. Microstructural evolution of eutectic Au-Sn solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ho Geon

    2002-05-31

    Current trends toward miniaturization and the use of lead(Pb)-free solder in electronic packaging present new problems in the reliability of solder joints. This study was performed in order to understand the microstructure and microstructural evolution of small volumes of nominally eutectic Au-Sn solder joints (80Au-20Sn by weight), which gives insight into properties and reliability.

  9. Microstructural evolution of eutectic Au-Sn solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ho Geon [Univ. of California, Berkeley, CA (United States)

    2002-05-01

    Current trends toward miniaturization and the use of lead(Pb)-free solder in electronic packaging present new problems in the reliability of solder joints. This study was performed in order to understand the microstructure and microstructural evolution of small volumes of nominally eutectic Au-Sn solder joints (80Au-20Sn by weight), which gives insight into properties and reliability.

  10. Testing of printed circuit board solder joints by optical correlation

    Science.gov (United States)

    Espy, P. N.

    1975-01-01

    An optical correlation technique for the nondestructive evaluation of printed circuit board solder joints was evaluated. Reliable indications of induced stress levels in solder joint lead wires are achievable. Definite relations between the inherent strength of a solder joint, with its associated ability to survive stress, are demonstrable.

  11. 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

    Purpose:The aim of this work is to investigate the decomposition behaviour of the activator species commonly used in the wave solder no-clean flux systems and to estimate the residue amount left after subjecting the samples to simulated wave soldering conditions. Design/methodology/approach: Chan......Purpose:The aim of this work is to investigate the decomposition behaviour of the activator species commonly used in the wave solder no-clean flux systems and to estimate the residue amount left after subjecting the samples to simulated wave soldering conditions. Design....../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......-malic). The decomposition patterns of solder flux activators depend on their chemical nature, time of heat exposure and substrate materials. Evaporation of the residue from the surface of different materials (laminate with solder mask, copper surface or glass surface) was found to be more pronounced for succinic...

  12. A Study of the Interface of Soldered Joints of SnInAgTi Active Solder with Ito Ceramics

    OpenAIRE

    M. Provazník; R. Koleňák

    2010-01-01

    This paper presents an analysis of the solderability ITO ceramics (In2O3/SnO2). The soft active solder SnInAgeTi was used for the experiments. The solder was activated by power ultrasound in air without flux. An analysis of the interface of the phases between the solder and the ceramic was carried out in order to discover the ultrasonic impacts on the active metal and to identify the mechanism of the joint on the ceramic side.

  13. 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..

  14. 基于SMT技术的组装新工艺探讨%New Assembly Process Discussion Based on SMT

    Institute of Scientific and Technical Information of China (English)

    赵少伟; 张婧亮; 韩春

    2016-01-01

    随着SMT技术在深度和规模上不断发展,SMT技术的应用领域不断扩大,从传统的板级组装逐步扩展到器件级组装和模块级组装,并融合创新出很多新的研究热点。通过摸索实践,对基于SMT技术衍生发展的几个新兴技术进行分析,主要包括在板PoP工艺、WLCSP芯片DCA组装工艺、MOB组装工艺和SIP工艺,阐述其工艺内含、实现方式、技术难点及实践体会。%With the continuous development of the SMT technology in depth and scale, the application of the technology has been exploring increasingly from the PCBA to device and Module assembly. And some new research hotspot is developing on it. Provide an overview of the research hotspot, concluding the PoP on board, WLCSP with DCA, MOB and SIP process. Discuss the structural forms, the processing, the difficulties and some practical experiences.

  15. Capillary wave formation on excited solder jet and fabrication of lead-free solder ball

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shu-guang; HE Li-jun; ZHU Xue-xin; ZHANG Shao-ming; SHI Li-kai; XU Jun

    2005-01-01

    A survey of solder ball production processes especially focusing on disturbed molten metal jet breakup process was made. Then the formation of capillary wave on tin melt jet in the way of rapid solidification was studied. A semi-empirical formula, which can be written as λ = Cvib (σ/ρ)1/3f-2/3 to predict the relationship between wavelength of capillary wave and frequency of imposed vibration was obtained. Sn-4.0Ag-0.5Cu lead free solder ball was successfully produced with tight distribution and good sphericity. The excited jet breakup process is promising for cost effectively producing solder ball.

  16. Solder Joint Health Monitoring Testbed System

    Science.gov (United States)

    Delaney, Michael M.

    2009-01-01

    The density and pin count for Field Programmable Gate Arrays (FPGAs) has been increasing, and has exceeded current methods of solder joint inspection, making early detection of failures more problematic. These failures are a concern for both flight safety and maintenance in commercial aviation. Ridgetop Group, Inc. has developed a method for detecting solder joint failures in real time. The NASA Dryden Flight Research Center is developing a set of boards to test this method in ground environmental and accelerated testing as well as flight test on a Dryden F-15 or F-18 research aircraft. In addition to detecting intermittent and total solder joint failures, environmental data on the boards, such as temperature and vibration, will be collected and time-correlated to aircraft state data. This paper details the technical approach involved in the detection process, and describes the design process and products to date for Dryden s FPGA failure detection boards.

  17. Moisture and aging effects of solder wettability of copper surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, C.L.; Sorensen, N.R.; Lucero, S.J.

    1996-12-01

    Solderability is a critical property of electronic assembly that affects both manufacturing efficiency and product reliability. There is often a considerable time interval between initial fabrication of a circuit board or component and its use at the assembly level. Parts are often stored under a variety of conditions, usually not controlled. Solder wettability can soon deteriorate during storage, especially in extreme environments. This paper describes ongoing efforts at Sandia to quantify solder wettability on bare and aged Cu surfaces. In addition, organic solderability preservatives (OSPs) were applied to the bare Cu to retard solderability loss due to aging. The OSPs generally performed well, although wetting did decrease with exposure time.

  18. Lead (Pb)-Free Solder Applications

    Energy Technology Data Exchange (ETDEWEB)

    VIANCO,PAUL T.

    2000-08-15

    Legislative and marketing forces both abroad and in the US are causing the electronics industry to consider the use of Pb-free solders in place of traditional Sn-Pb alloys. Previous case studies have demonstrated the satisfactory manufacturability and reliability of several Pb-free compositions for printed circuit board applications. Those data, together with the results of fundamental studies on Pb-free solder materials, have indicated the general feasibility of their use in the broader range of present-day, electrical and electronic components.

  19. Effects of PCB thickness on adjustable fountain wave soldering

    Indian Academy of Sciences (India)

    M S Abdul Aziz; M Z Abdullah; C Y Khor; A Jalar; M A Bakar; W Y W Yusoff; F Che Ani; Nobe Yan; M Zhou; C Cheok

    2015-10-01

    This study investigates the effects of printed circuit board (PCB) thickness on adjustable fountain and conventional wave soldering. The pin-through-hole (PTH) vertical fill is examined with three PCBs of different thicknesses (i.e., 1.6, 3.1, and 6.0 mm) soldered through adjustable fountain and conventional wave soldering at conveyor angles of 0° and 6°. The vertical fill of each PCB is the focus. The PTH solder profile is inspected with a non-destructive X-ray computed tomography scanning machine. The percentages of the PTH vertical fill of both soldering processes are also estimated and compared. The aspect ratio of the PCB is also investigated. Experimental results reveal that adjustable fountain wave soldering yields better vertical fill than conventional wave soldering. The vertical fill level of adjustable fountain wave soldering is 100%, 90%, and 50% for the 1.6, 3.1, and 6.0 mm PCB thickness, respectively. FLUENT simulation is conducted for the vertical fill of the solder profile. Simulation and experimental results show that the PTH solder profiles of the two soldering processes are almost identical. The effect of PCB thickness on PTH voiding is also discussed.

  20. Prototype circuit boards assembled with non-lead bearing solders

    Energy Technology Data Exchange (ETDEWEB)

    Vianco, P.T.; Rejent, J.A.

    1998-04-01

    The 91.84Sn-3.33Ag-4.83Bi and 96.5Sn-3.5Ag Pb-free solders were evaluated for surface mount circuit board interconnects. The 63Sn-37Pb solder provided the baseline data. All three solders exhibited suitable manufacturability per a defect analyses of circuit board test vehicles. Thermal cycling had no significant effect on the 91.84Sn-3.33Ag-4.83Bi solder joints. Some degradation in the form of grain boundary sliding was observed in 96.5Sn-3.5Ag and 63Sn-37Pb solder joints. The quality of the solder joint microstructures showed a slight degree of degradation under thermal shock exposure for all of the solders tested. Trends in the solder joint shear strengths could be traced to the presence of Pd in the solder, the source of which was the Pd/Ni finish on the circuit board conductor features. The higher, intrinsic strengths of the Pb-free solders encouraged the failure path to be located in proximity to the solder/substrate interface where Pd combined with Sn to form brittle PdSn{sub 4} particles, resulting in reduced shear strengths.

  1. Automatic computer-aided system of simulating solder joint formation

    Science.gov (United States)

    Zhao, Xiujuan; Wang, Chunqing; Zheng, Guanqun; Wang, Gouzhong; Yang, Shiqin

    1999-08-01

    One critical aspect in electronic packaging is the fatigue/creep-induced failure in solder interconnections, which is found to be highly dependent on the shape of solder joints. Thus predicting and analyzing the solder joint shape is warranted. In this paper, an automatic computer-aided system is developed to simulate the formation of solder joint and analyze the influence of the different process parameters on the solder joint shape. The developed system is capable of visually designing the process parameters and calculating the solder joint shape automatically without any intervention from the user. The automation achieved will enable fast shape estimation with the variation of process parameters without time consuming experiments, and the simulating system provides the design and manufacturing engineers an efficient software tools to design soldering process in design environment. Moreover, a program developed from the system can serve as the preprocessor for subsequent finite element joint analysis program.

  2. Microstructural Evolution of Lead-Free Solder Joints in Ultrasonic-Assisted Soldering

    Science.gov (United States)

    Ji, Hongjun; Wang, Qiang; Li, Mingyu

    2016-01-01

    Solder joint reliability greatly depends on the microstructure of the solder matrix and the morphology of intermetallic compounds (IMCs) in the joints. Addition of strengthening phases such as carbon nanotubes and ceramic particles to solder joints to improve their properties has been widely studied. In this work, ultrasonic vibration (USV) of casting ingots was applied to considerably improve their microstructure and properties, and the resulting influence on fluxless soldering of Cu/Sn-3.0Ag-0.5Cu/Cu joints and their microstructural evolution was investigated. It was demonstrated that USV application during reflow of Sn-based solder had favorable effects on β-Sn grain size refinement as well as the growth and distribution of various IMC phases within the joints. The β-Sn grain size was significantly refined as the ultrasound power was increased, with a reduction of almost 90% from more than 100 μm to below 10 μm. Long and large Cu6Sn5 tubes in the solder matrix of the joints were broken into tiny ones. Needle-shaped Ag3Sn was transformed into flake-shaped. These IMCs were mainly precipitated along β-Sn phase boundaries. High-temperature storage tests indicated that the growth rate of interfacial IMCs in joints formed with USV was slower than in conventional reflow joints. The mechanisms of grain refinement and IMC fragmentation are discussed and related to the ultrasonic effects.

  3. Multilead, Vaporization-Cooled Soldering Heat Sink

    Science.gov (United States)

    Rice, John

    1995-01-01

    Vaporization-cooled heat sink proposed for use during soldering of multiple electrical leads of packaged electronic devices to circuit boards. Heat sink includes compliant wicks held in grooves on edges of metal fixture. Wicks saturated with water. Prevents excessive increases in temperature at entrances of leads into package.

  4. Soldering and Mass Generation in Four Dimensions

    CERN Document Server

    Banerjee, R; Banerjee, Rabin; Wotzasek, Clovis

    2000-01-01

    We propose bosonised expressions for the chiral Schwinger models in four dimensions. Then, in complete analogy with the two dimensional case, we show the soldering of two bosonised chiral Schwinger models with opposite chiralities to yield the bosonised Schwinger model in four dimensions. The implications of the Schwinger model or its chiral version, as known for two dimensions, thereby get extended to four dimensions.

  5. Solderability test development. Final report. [Meniscograph tests

    Energy Technology Data Exchange (ETDEWEB)

    Jarboe, D.M.

    1977-10-01

    Operating procedures and data reduction techniques applicable to the Meniscograph (General Electric Company, Limited) were developed. Using force-time traces from tests involving various sample materials and configurations, flux types, and test temperatures, the wetting rate and contact angle were obtained through statistical treatment of the data. This information provides a means of directly correlating solderability with the physical phenomenon of wetting.

  6. High-precision opto-mechanical lens system for space applications assembled by innovative local soldering technique

    Science.gov (United States)

    Ribes, P.; Koechlin, C.; Burkhardt, T.; Hornaff, M.; Burkhardt, D.; Kamm, A.; Gramens, S.; Beckert, E.; Fiault, G.; Eberhardt, R.; Tünnermann, A.

    2016-02-01

    Solder joining using metallic solder alloys is an alternative to adhesive bonding. Laser-based soldering processes are especially well suited for the joining of optical components made of fragile and brittle materials such as glasses, ceramics and optical crystals. This is due to a localized and minimized input of thermal energy. Solderjet bumping technology has been used to assemble a lens mount breadboard taking as input specifications the requirements found for the optical beam expander for the European Space Agency (ESA) EarthCare Mission. The silica lens and a titanium barrel have been designed and assembled with this technology in order to withstand the stringent mission demands; handling high mechanical and thermal loads without losing its optical performances. Finally a high-precision opto-mechanical lens mount has been assembled with a minimal localized stress (<1 MPa) showing outstanding performances in terms of wave-front error measurements and beam depolarization ratio before and after environmental tests.

  7. A Study on the Performance of Drilling Mud Thinner Sulfomethylated Tannin of Tara(SMT-T)%钻井泥浆稀释剂塔拉磺甲基化单宁(SMT-T)性能的研究

    Institute of Scientific and Technical Information of China (English)

    张建云; 李志国; 吴昊; 包松莲; 杨时宇

    2007-01-01

    对塔拉豆荚壳经浸提、磺甲基化、络合等工艺制备的塔拉磺甲基化单宁(SMT-T)的性能进行了初步研究,结果表明:SMT-T用于钻井泥浆稀释剂是可行的;SMT-T的干燥方式及其添加量即 0.5 % 和 2.0 % 对钻井泥浆降黏率无明显差异;当温度为 180 ℃、加入 2 % 的盐,其降黏率在 80 % 以上;当温度在200~220 ℃时,其降黏率为 82.5 %~86.4 %;SMT-T质量指标测定超过现行行业标准SY/T 5091-1993《钻井液用磺化栲酸》.SMT-T适宜在180~220 ℃的深井、气井、高密井等使用.

  8. Task 7: Die soldering during host site testing. Final report, January1--December 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Goodwin, F.E. [International Lead Zinc Research Organization, Inc., Research Triangle Park, NC (United States); Walkington, W.G. [Walkington (William G.), Cottage Grove, WI (United States)

    1998-01-31

    To provide industrial confirmation of laboratory results produced in Task 6 of this project, five industrial trials were organized with cooperative die casters in the USA. Components cast during these trials ranged from functional electronic heat sinks to decorative household plumbing components. Whereas laboratory work indicated that die temperature and draft angle were the most important process factors influencing solder accumulation, it was not possible to vary draft angle on the established production dies used for these trials. Substantial variations in die temperature were realized however and also die surface conditions were varied, confirming the influence of a secondary variable in the laboratory investigation. Substantial evidence from the trials indicated that die surface temperature is the most important factor for controlling solder build up. The surface roughness of the die casting die greatly influenced the number of castings that could be run before solder initially appeared. Development of careful thermal management techniques, now judged to be beyond the capabilities of most US die casters, will be necessary to control incidences of die soldering found in typical production. Thermal control will involve both control of the bulk die temperature through use of thermally controlled cooling lines, and also regulation of surface temperature by well controlled cooling lines, and also regulation of surface temperature by well controlled die spraying (lubrication) techniques. Further research, development and technology transfer to enhance thermal control capabilities of US die casters is recommended.

  9. Microwave Tissue Soldering for Immediate Wound Closure

    Science.gov (United States)

    Arndt, G. Dickey; Ngo, Phong H.; Phan, Chau T.; Byerly, Diane; Dusl, John; Sognier, Marguerite A.; Carl, James

    2011-01-01

    A novel approach for the immediate sealing of traumatic wounds is under development. A portable microwave generator and handheld antenna are used to seal wounds, binding the edges of the wound together using a biodegradable protein sealant or solder. This method could be used for repairing wounds in emergency settings by restoring the wound surface to its original strength within minutes. This technique could also be utilized for surgical purposes involving solid visceral organs (i.e., liver, spleen, and kidney) that currently do not respond well to ordinary surgical procedures. A miniaturized microwave generator and a handheld antenna are used to deliver microwave energy to the protein solder, which is applied to the wound. The antenna can be of several alternative designs optimized for placement either in contact with or in proximity to the protein solder covering the wound. In either case, optimization of the design includes the matching of impedances to maximize the energy delivered to the protein solder and wound at a chosen frequency. For certain applications, an antenna could be designed that would emit power only when it is in direct contact with the wound. The optimum frequency or frequencies for a specific application would depend on the required depth of penetration of the microwave energy. In fact, a computational simulation for each specific application could be performed, which would then match the characteristics of the antenna with the protein solder and tissue to best effect wound closure. An additional area of interest with potential benefit that remains to be validated is whether microwave energy can effectively kill bacteria in and around the wound. Thus, this may be an efficient method for simultaneously sterilizing and closing wounds.

  10. Preparation of solder pads by selective laser scanning

    Institute of Scientific and Technical Information of China (English)

    Wenqing Shi; Yongqiang Yang; Yanlu Huang; Guoqiang Wei; Wei Guo

    2009-01-01

    We propose a new laser preparation technique to solder Sn-Ag3.5-Cu0.7 on a copper clad laminate (CCL). The experiment is conducted by selective laser heating and melting the thin solder layer and then preprint-ing it on CCL in order to form the matrix with solder pads. Through the analysis of macro morphology of the matrix with solder pads and microstructure of single pads, this technique is proved to be suitable for preparing solder pads and that the solder pads are of good mechanical properties. The results also reveal that high frequency laser pulse is beneficial to the formation of better solder pad, and that the 12-W fiber laser with a beam diameter of 0.030 mm can solder Sn-Ag3.5-Cu0.7 successfully on CCL at 500-kHz pulse frequency. The optimized parameters of laser soldering on CCL are as follows: the laser power is 12 W, the scanning speed is 1.0 mm/s, the beam diameter is 0.030 mm, the lead-free solder is Sn-Ag3.5-Cu0.7, and the laser pulse frequency is 500 kHz.

  11. RECONSTRUCTING PALEO-SMT POSITIONS ON THE CASCADIA MARGIN USING MAGNETIC SUSCEPTIBILITY

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Joel [Univ. of New Hampshire, Durham, NH (United States); Phillips, Stephen [Univ. of New Hampshire, Durham, NH (United States)

    2014-09-30

    Magnetic susceptibility (κ) is a mixed signal in marine sediments, representing primary depositional and secondary diagenetic processes. Production of hydrogen sulfide via anaerobic oxidation of methane (AOM) at the sulfate-methane transition (SMT) and organoclastic sulfate reduction above the SMT can result in the dissolution of iron oxides, altering κ in sediments in methane gas and gas hydrate bearing regions. We investigated records of κ on the Cascadia margin (ODP Sites 1249 and 1252; IODP Site 1325) using a Zr/Rb heavy mineral proxy from XRF core scanning to identify intervals of primary detrital magnetic susceptibility and intervals and predict intervals affected by magnetite dissolutions. We also measured total sulfur content, grain size distributions, total organic carbon (TOC) content, and magnetic mineral assemblage. The upper 100 m of Site 1252 contains a short interval of κ driven by primary magnetite, with multiple intervals (> 90 m total) of decreased κ correlated with elevated sulfur content, consistent with dissolution of magnetite and re-precipitation of pyrite. In the upper 90 m of Site 1249, κ is almost entirely altered by diagenetic processes, with much of the low κ explained by a high degree of pyritization, and some intervals affected by the precipitation of magnetic iron sulfides. At Site 1325, κ between 0-20 and 51-73 mbsf represents primary mineralogy, and in the interval 24-51 mbsf, κ may be reduced due to pyritization. This integrated approach allows for a prediction of primary κ and the amount of κ loss at each site when compared to actual κ measurements. In the case of magnetite dissolution and full pyritization, these drawdowns in κ are supported by sulfur measurements, and the exposure times of magnetite to hydrogen sulfide can be modeled. The presence of methane and methane hydrates at these sites, as well as large variations in TOC content, suggest that the past migration rates of the SMT and variation in sulfate

  12. Effects of AlN Nanoparticles on the Microstructure, Solderability, and Mechanical Properties of Sn-Ag-Cu Solder

    Science.gov (United States)

    Jung, Do-Hyun; Sharma, Ashutosh; Lim, Dong-Uk; Yun, Jong-Hyun; Jung, Jae-Pil

    2017-09-01

    The addition of nanosized AlN particles to Sn-3.0 wt pctAg-0.5 wt pctCu (SAC305) lead-free solder alloy has been investigated. The various weight fractions of AlN (0, 0.03, 0.12, 0.21, 0.60 wt pct) have been dispersed in SAC305 solder matrix by a mechanical mixing and melting route. The influences of AlN nanosized particles on the microstructure, mechanical properties, and solderability ( e.g., spreadability and wettability) have been carried out. The structural and morphological features of the nanocomposite solder were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and transmission electron microscope (TEM). The experimental results show that the best combination of solderability and mechanical properties is obtained at 0.21 wt pct AlN in the solder matrix. The reinforced composite solder with 0.21 wt pct AlN nanoparticles shows ≈25 pct improvement in ultimate tensile strength (UTS), and ≈4 pct increase in the spreadability. In addition, the results of microstructural analyses of composite solders indicate that the nanocomposite solder, especially reinforced with 0.21 wt pct of AlN nanoparticles, exhibits better microstructure and improved elongation percentage, compared with the monolithic SAC305 solder.

  13. SMT Lead-free Solder Paste Deposit Quality Optimization by Taguchi Method%用田口方法优化SMT无铅焊膏印刷质量

    Institute of Scientific and Technical Information of China (English)

    罗兵

    2008-01-01

    焊膏印刷是PCB贴片安装的重要环节,采用无铅焊膏后,由于焊膏物理性能的变化,需要重新摸索调整无铅焊膏的印刷参数,以获得最好的焊膏印刷质量.影响质最的多个因子多水平的完备试验是不现实的,文中采用田口方法试验,得到了在工程实际中适合无铅焊膏印刷的多个参数的近似最佳数值.该方法还可以广泛应用干电子产品质量控制优化.

  14. Sn-Ag-Cu Nanosolders: Solder Joints Integrity and Strength

    Science.gov (United States)

    Roshanghias, Ali; Khatibi, Golta; Yakymovych, Andriy; Bernardi, Johannes; Ipser, Herbert

    2016-08-01

    Although considerable research has been dedicated to the synthesis and characterization of lead-free nanoparticle solder alloys, only very little has been reported on the reliability of the respective joints. In fact, the merit of nanoparticle solders with depressed melting temperatures close to the Sn-Pb eutectic temperature has always been challenged when compared with conventional solder joints, especially in terms of inferior solderability due to the oxide shell commonly present on the nanoparticles, as well as due to compatibility problems with common fluxing agents. Correspondingly, in the current study, Sn-Ag-Cu (SAC) nanoparticle alloys were combined with a proper fluxing vehicle to produce prototype nanosolder pastes. The reliability of the solder joints was successively investigated by means of electron microscopy and mechanical tests. As a result, the optimized condition for employing nanoparticles as a competent nanopaste and a novel procedure for surface treatment of the SAC nanoparticles to diminish the oxide shell prior to soldering are being proposed.

  15. Investigation of Solder Cracking Problems on Printed Circuit Boards

    Science.gov (United States)

    Berkebile, M. J.

    1967-01-01

    A Solder Committee designated to investigate a solder cracking phenomena occurring on the SATURN electrical/electronic hardware found the cause to be induced stress in the soldered connections rather than faulty soldering techniques. The design of the printed circuit (PC) board assemblies did not allow for thermal expansion of the boards that occurred during normal operation. The difference between the thermal expansion properties of the boards and component lead materials caused stress and cracking in the soldered connections. The failure mechanism and various PC boards component mounting configurations are examined in this report. Effective rework techniques using flanged tubelets, copper tubelets, and soft copper wiring are detailed. Future design considerations to provide adequate strain relief in mounting configurations are included to ensure successful solder terminations.

  16. EVOLUTION OF MICROSTRUCTURE OF Sn-Ag-Cu LEAD-FREE FLIP CHIP SOLDER JOINTS DURING AGING PROCESS

    Institute of Scientific and Technical Information of China (English)

    Y.H. Tian; C.Q. Wang; W.F. Zhou

    2006-01-01

    Flip chip bonding has become a primary technology that has found application in the chip interconnection process in the electronic manufacturing industry in recent years. The solder joints of the flip chip bonding are small and consist of complicated microstructures such as Sn solution,eutectic mixture, and intermetallic compounds (IMCs), whose mechanical performance is quite different from the original solder bulk. The evolution of microstructure of the flip chip solder joints under thermal aging was analyzed. The results show that with an increase in aging time, coarsening of solder bulk matrix and AuSn4 IMCs occurred within the solder. The IMCs that are formed at the bottom side of the flip chip bond were different from those on the top side during the aging process. ( Cu, Ni, Au )6Sn5 were formed at the interfaces of both sides, and large complicated (Au, Ni,Cu)Sn4 IMCs appeared for some time near the bottom interface after aging, but they disappeared again and thus ( Cu, Ni,Au )6Sns IMC thickness increased considerably. The influence of reflow times during the flip chip bonding (as-bonded condition) on the characteristics of interfacial IMCs was weakened when subjected to the aging process.

  17. The nucleolar SUMO-specific protease SMT3IP1/SENP3 attenuates Mdm2-mediated p53 ubiquitination and degradation

    Energy Technology Data Exchange (ETDEWEB)

    Nishida, Tamotsu, E-mail: nishida@gene.mie-u.ac.jp [Department of Human Functional Genomics, Life Science Research Center, Mie University, 1577 Kurima-machiya, Tsu 514-8507 (Japan); Yamada, Yoshiji [Department of Human Functional Genomics, Life Science Research Center, Mie University, 1577 Kurima-machiya, Tsu 514-8507 (Japan)

    2011-03-11

    Research highlights: {yields} SMT3IP1 interacts with p53 and Mdm2, and desumoylates both proteins. {yields} SMT3IP1 competes with p53 for binding to the central acidic domain of Mdm2. {yields} SMT3IP1 binding to Mdm2 inhibits Mdm2-mediated p53 ubiquitination and degradation. {yields} We postulate that SMT3IP1 acts as a new regulator of the p53-Mdm2 pathway. -- Abstract: SUMO (small ubiquitin-like modifier) modification plays multiple roles in several cellular processes. Sumoylation is reversibly regulated by SUMO-specific proteases. SUMO-specific proteases have recently been implicated in cell proliferation and early embryogenesis, but the underlying mechanisms remain unknown. Here, we show that a nucleolar SUMO-specific protease, SMT3IP1/SENP3, controls the p53-Mdm2 pathway. We found that SMT3IP1 interacts with p53 and Mdm2, and desumoylates both proteins. Overexpression of SMT3IP1 in cells resulted in the accumulation of Mdm2 in the nucleolus and increased stability of the p53 protein. In addition, SMT3IP1 bound to the acidic domain of Mdm2, which also mediates the p53 interaction, and competed with p53 for binding. Increasing expression of SMT3IP1 suppressed Mdm2-mediated p53 ubiquitination and subsequent proteasomal degradation. Interestingly, the desumoylation activity of SMT3IP1 was not necessary for p53 stabilization. These results suggest that SMT3IP1 is a new regulator of the p53-Mdm2 pathway.

  18. Anomalous creep in Sn-rich solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ho Geon; Morris Jr., John W.; Hua, Fay

    2002-03-15

    This paper discusses the creep behavior of example Sn-rich solders that have become candidates for use in Pb-free solder joints. The specific solders discussed are Sn-3.5Ag, Sn-3Ag-0.5Cu, Sn-0.7Cu and Sn-10In-3.1Ag, used in thin joints between Cu and Ni-Au metallized pads.

  19. THERMAL PROCESS OF VACUUM FLUXLESS LASERSOLDERING AND ANALYSIS ON SOLDER SPREADING AND WETTING

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to study the mechanism of vacuum fluxless soldering on the conditions of laser heating, the method of measuring temperature by the thermocouple is used to analyze the spreading and wetting process of boh fluxless SnPb solder in the vacuum surroundings and flux SnPb solder on Cu pad. Solder spreading and wetting affected by the soldering thermal process is also discussed according to the thermodynamics principle. Results show that vacuum fluxless soldering demands higher temperature, and the fall of the solder su rface tension is the important factor achieving fluxless laser soldering.

  20. Break-up Process of Perturbed Molten Metal Jet and Preparation of Lead-Free Solder Balls

    Institute of Scientific and Technical Information of China (English)

    He Lijun; Zhang Shuguang; Zhang Shaoming; Xu Jun; Shi Likai

    2004-01-01

    Solder balls, which are used in advanced electronics packages such as BGA (Ball Grid Array) and CSP (Chip Scale Package) to substitute the leads and realize the electrical and mechanical connections between substrate and chip,have severe specifications in diameter tolerance, roundness and surface quality, and therefore challenge the traditional technologies for fabrication of metallic particles and powders. The present work made a survey of perturbed molten metal jet break-up process, observed the formation and growth of capillary wave of tin-lead melt jet by way of rapid solidification, and on the basis of the above research, successfully obtained tin-lead eutectic and Sn-4.0Ag-0.5Cu lead free solder balls with tight distribution and good sphericity of particles through optimization of processing parameters, forming a solid base for cost effectively producing solder balls.

  1. Solderability preservation through the use of organic inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, N.R.; Hosking, F.M.

    1994-12-01

    Organic inhibitors can be used to prevent corrosion of metals and have application in the electronics industry as solderability preservatives. We have developed a model to describe the action of two inhibitors (benzotriazole and imidazole) during the environmental aging and soldering process. The inhibitors bond with the metal surface and form a barrier that prevents or retards oxidation. At soldering temperatures, the metal-organic complex breaks down leaving an oxide-free metal surface that allows excellent wetting by molten solder. The presence of the inhibitor retards the wetting rate relative to clean copper, but provides a vast improvement relative to oxidized copper.

  2. Aging, stressing and solderability of electroplated and electroless copper

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, N.R.; Hosking, F.M.

    1995-08-01

    Organic inhibitors can be used to prevent corrosion of metals have application in the electronics industry as solderability preservatives. We have developed a model to describe the action of two inhibitors (benzotriazole and imidazole) during the environmental aging and soldering process. The inhibitors bond with the metal surface and form a barrier that prevents or retards oxidation. At soldering temperatures, the metal-organic complex breaks down leaving an oxide-free metal surface that allows excellent wetting by the molten solder. The presence of the inhibitor retards the wetting rate relative to clean copper but provides a vast improvement relative to oxidized copper.

  3. High temperature solder alloys for underhood applications: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kern, J.A. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Mechanical Engineering; Drewien, C.A.; Yost, F.G.; Sackinger, S. [Sandia National Laboratories, Albuquerque, NM (United States); Weiser, M.W. [Johnson-Mathey Electronics Corp., Spokane, WA (United States)

    1996-06-01

    In this continued study, the microstructural evolution and peel strength as a function of thermal aging were evaluated for four Sn-Ag solders deposited on double layered Ag-Pt metallization. Additionally, activation energies for intermetallic growth over the temperature range of 134 to 190{degrees}C were obtained through thickness measurements of the Ag-Sn intermetallic that formed at the solder-metallization interface. It was found that Bi-containing solders yielded higher activation energies for the intermetallic growth, leading to thicker intermetallic layers at 175 and 190{degrees}C for times of 542 and 20.5 hrs, respectively, than the solders free of Bi. Complete reaction of the solder with the metallization occurred and lower peel strengths were measured on the Bi-containing solders. In all solder systems, a Ag-Sn intermetallic thickness of greater than {approximately}7 {mu}m contributed to lower peel strength values. The Ag-Sn binary eutectic composition and the Ag-Sn-Cu ternary eutectic composition solders yielded lower activation energies for intermetallic formation, less microstructural change with time, and higher peel strengths; these solder systems were resilient to the effects of temperatures up to 175{degrees}C. Accelerated isothermal aging studies provide useful criteria for recommendation of materials systems. The Sn-Ag and Sn-Ag-Cu eutectic compositions should be considered for future service life and reliability studies based upon their performance in this study.

  4. Packaging of hard solder 500W QCW diode laser array

    Science.gov (United States)

    Li, Xiaoning; Wang, Jingwei; Hou, Dong; Nie, Zhiqiang; Liu, Xingsheng

    2016-03-01

    The package structure critically influences the major characteristics of diode laser, such as thermal behavior, output power, wavelength and smile effect. In this work, a novel micro channel cooler (MCC) for stack array laser with good heat dissipation capability and high reliability is presented. Numerical simulations of thermal management with different MCC structure are conducted and analyzed. Based on this new MCC packaging structure, a series of QCW 500W high power laser arrays with hard solder packaging technology has been fabricated. The performances of the laser arrays are characterized. A narrow spectrum of 3.12 nm and an excellent smile value are obtained. The lifetime of the laser array is more than 1.38×109 shots and still ongoing.

  5. 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

  6. Improved protein overexpression and purification strategies for structural studies of cyanobacterial metal-responsive transcription factor, SmtB from marine Synechococcus sp. PCC 7002.

    Science.gov (United States)

    Mahadev, Shelake Rahul; Hayashi, Hidenori; Ikegami, Takahisa; Abe, Shunnosuke; Morita, Eugene Hayato

    2013-12-01

    There are structural and functional differences in SmtB homologs, metal-responsive transcription factors responsible for sensing of excess heavy metal ions in marine and freshwater cyanobacterial strains. The structure of SmtB from freshwater Synechococcus sp. strain PCC 7942 is elucidated with nuclear magnetic resonance (NMR) and crystallography techniques. But knowledge about the functioning of SmtB homologs from marine species is limited till date. To enable NMR spectroscopic studies for investigating structural and functional aspects, modified protocols with higher yields of isotopically labeled SmtB, from marine species like Synechococcus sp. PCC 7002 are essential. In this study, smtB gene was cloned from genome of Synechococcus sp. PCC 7002 and overexpression protocol for recombinant SmtB was standardized in Escherichia coli containing T7 RNA polymerase/promoter system. Further, the protocol for large-scale production, isotope labeling with (15)N, and purification of recombinant SmtB in E. coli BL21(DE3)/pLysS cells was developed. Purified recombinant protein was successfully used for NMR spectroscopy experiments. These results indicate that the overexpression technique now developed is applicable to the structural and functional studies for the proteins being homologous to cyanobacterial SmtB from Synechococcus sp. PCC 7002.

  7. 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.

  8. Effects of rare earth element Ce on solderabilities of micron-powdered Sn-Ag-Cu solder

    Institute of Scientific and Technical Information of China (English)

    XUE Song-bai; YU Sheng-lin; WANG Xu-yan; LIU lin; HU Yong-fang; YAO Li-hua

    2005-01-01

    Several important properties of the micron-powdered Sn-Ag-Cu-Ce solder, including the spreadability, spreading ratio, wetting time, and melting point, were investigated for verifying the effects of rare earth element Ce on solderabilities of micron-powdered Sn-Ag-Cu solder. The solidus and the liquidus of the micron-powdered Sn-Ag-Cu-Ce solder are 193.6℃ and 218.4℃, respectively, about 28℃ and 3℃ lower than the melting point of the block Sn-Ag-Cu solder, which reminds the existence of the surface effect of the micron-powdered solder. By adding Ce into Sn-Ag-Cu alloy, its wetting time on pure copper can be obviously decreased. For the Sn-Ag-Cu-0.03%Ce, the soldering temperature is 250℃, and the wetting time on pure copper is close to 1s, with the soldering temperature approaching to 260℃, the wetting time is dropped to 0.8s, which is close to the wetting time, 0.68s, of Sn-Pb solder at 235℃.

  9. A Study of the Interface of Soldered Joints of SnInAgTi Active Solder with Ito Ceramics

    Directory of Open Access Journals (Sweden)

    M. Provazník

    2010-01-01

    Full Text Available This paper presents an analysis of the solderability ITO ceramics (In2O3/SnO2. The soft active solder SnInAgeTi was used for the experiments. The solder was activated by power ultrasound in air without flux. An analysis of the interface of the phases between the solder and the ceramic was carried out in order to discover the ultrasonic impacts on the active metal and to identify the mechanism of the joint on the ceramic side.

  10. Report on FY15 Alloy 617 SMT Creep-Fatigue Test Results

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanli [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jetter, Robert I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Baird, Seth T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pu, Chao [Univ. of Tennessee, Knoxville, TN (United States); Sham, Sam [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-06-22

    viability of the Alloy 617 Code Case, the use of the current elastic analysis based rules in Subsection NH for the evaluation of strain limits (a precursor for the creep-fatigue rules) and the creep-fatigue rules themselves have been deemed inappropriate for Alloy 617 at temperatures above 650C (Corum and Brass, 1991). The rationale for this exclusion is that at higher temperatures it is not feasible to decouple plasticity and creep, which is the basis for the current simplified rules. This temperature, 650C, is well below the temperature range of interest for this material for the High Temperature Gas Cooled Reactor (HTGR) as well as the VHTR. The only current alternative is, thus, a full inelastic analysis which requires sophisticated material models which have not yet been formulated and verified. To address the prohibition on the use of current methods at very high temperatures, proposed Code rules have been developed which are based on the use of elastic-perfectly plastic (E-PP) analysis methods and which are expected to be applicable to very high temperatures. To provide data to implement the proposed rules and to verify their application, a series of tests have been initiated. One test concept, the Simplified Model Test (SMT), takes into account the stress and strain redistribution in real structures by including representative follow-up characteristics in the test specimen. The correlation parameter between test and design is the elastically calculated strain, and the dependent test variable is the observed cycles to failure. Although the initial priority for the SMT approach is to generate data to support validation of the E-PP Code Case for evaluation of creep-fatigue damage, the broader goal of the SMT approach is to develop a methodology for evaluation of creep fatigue damage which is simpler to implement than the current complex rules and applicable to the full temperature range from ambient conditions to the very high temperature creep regime of 900-950C. Also

  11. Interfacial Reaction Between Sn3.0Ag0.5Cu Solder and ENEPIG for Fine Pitch BGA by Stencil Printing

    Science.gov (United States)

    Liu, Ziyu; Cai, Jian; Wang, Qian; He, Xi; Chen, Yu

    2014-09-01

    In this work, solder balls in ball grid array packaging technology with the pitch of 300 μm were fabricated by stencil printing solder paste and then reflowed at high temperature. In order to evaluate the quality of solder ball after printing and reflowing processes, the mechanical performance of the joint between the solder balls and the pad was measured by shear test and the electrical resistance was tested after assembly of the substrate and printed circuit board. A comparative study of pad size on the interfacial reaction between solder paste and surface finish of electroless nickel-electroless palladium-immersion gold on the organic substrate was performed and then analyzed by observing the microstructure at the interface. Large discontinuous (Cu,Ni)6Sn5 was found at the interface of the solder with the pad size of 120 μm, while spalled (Pd,Ni)Sn4 and thin (Cu,Ni)6Sn5 layer appeared for a pad size of 140 μm. The IMC (intermetallic compounds) was determined by the residual Cu concentration, the Pd concentration in the solder, and the Ni2SnP barrier layer morphology at the interface, which were significantly influenced by the pad size. A reaction model during the reflow was proposed to illustrate the growth of the IMC and the relationship between the IMC and the pad size. With Pd concentration higher than the solubility of Pd in the solder, spalled (Pd,Ni)Sn4 took shape along the interface. The solubility of Pd was influenced by Ni concentration; however, the Ni diffusion from the substrate was largely dependent on the barrier layer Ni2SnP. Furthermore, the Ni diffusion also impacted the growth and morphology of (Cu,Ni)6Sn5, which was not only limited by the Cu concentration.

  12. Effect of 0.5 wt % Cu addition in Sn-3.5%Ag solder on the dissolution rate of Cu metallization

    Science.gov (United States)

    Alam, M. O.; Chan, Y. C.; Tu, K. N.

    2003-12-01

    The dissolution of thin film under-bump-metallization (UBM) by molten solder has been one of the most serious processing problems in electronic packaging technology. Due to a higher melting temperature and a greater Sn content, a molten lead-free solder such as eutectic SnAg has a faster dissolution rate of thin film UBM than the eutectic SnPb. The work presented in this paper focuses on the role of 0.5 wt % Cu in the base Sn-3.5%Ag solder to reduce the dissolution of the Cu bond pad in ball grid array applications. We found that after 0.5 wt % Cu addition, the rate of dissolution of Cu in the molten Sn-3.5%Ag solder slows down dramatically. Systematic experimental work was carried out to understand the dissolution behavior of Cu by the molten Sn-3.5%Ag and Sn-3.5%Ag-0.5%Cu solders at 230-250 °C, for different time periods ranging from 1 to 10 min. From the curves of consumed Cu thickness, it was concluded that 0.5 wt % Cu addition actually reduces the concentration gradient at the Cu metallization/molten solder interface which reduces the driving force of dissolution. During the dissolution, excess Cu was found to precipitate out due to heterogeneous nucleation and growth of Cu6Sn5 at the solder melt/oxide interface. In turn, more Cu can be dissolved again. This process continues with time and leads to more dissolution of Cu from the bond pad than the amount expected from the solubility limit, but it occurs at a slower rate for the molten Sn-3.5%Ag-0.5%Cu solder.

  13. 防错料系统在SMT过程中的应用%Application of Error Proof System to SMT

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      通过对SMT 生产线的连续跟踪,发现元件贴装错误是产品质量波动的一个重要隐患。对经常发生的错料问题进行了分析,从人、机、料、法和环等方面找出事件发生的深层次原因,并提出了相应的改善对策。采用新的防错料措施后,杜绝了错料再次发生,从而提高了 SMT 生产设备效率,提高了产品一次交检合格率,降低了返修率,保证了产品质量。%It is found that the error of mounting wrong component is an important problem for product quality through the continuous tracking of SMT production line. Analyze the wrong material problems often occurred from human, machine, material, method and environment, find out the reason of the events, and put forward the corresponding improvement countermeasures. Using the new measures of Error Proof System, eliminate the component placement error, thereby increase SMT production equipment efficiency, improve the first inspection pass rate of product, reduce the rate of repair, ensure the quality of the products.

  14. ILP/SMT-Based Method for Design of Boolean Networks Based on Singleton Attractors.

    Science.gov (United States)

    Kobayashi, Koichi; Hiraishi, Kunihiko

    2014-01-01

    Attractors in gene regulatory networks represent cell types or states of cells. In system biology and synthetic biology, it is important to generate gene regulatory networks with desired attractors. In this paper, we focus on a singleton attractor, which is also called a fixed point. Using a Boolean network (BN) model, we consider the problem of finding Boolean functions such that the system has desired singleton attractors and has no undesired singleton attractors. To solve this problem, we propose a matrix-based representation of BNs. Using this representation, the problem of finding Boolean functions can be rewritten as an Integer Linear Programming (ILP) problem and a Satisfiability Modulo Theories (SMT) problem. Furthermore, the effectiveness of the proposed method is shown by a numerical example on a WNT5A network, which is related to melanoma. The proposed method provides us a basic method for design of gene regulatory networks.

  15. Surface tension and reactive wetting in solder connections

    Energy Technology Data Exchange (ETDEWEB)

    Wedi, Andre; Schmitz, Guido [Institut fuer Materialphysik, Westf. Wilhelms-Universitaet, Wilhelm-Klemm-Strasse 10, 48149 Muenster (Germany)

    2011-07-01

    Wetting is an important pre-requisite of a reliable solder connection. However, it is only an indirect measure for the important specific energy of the reactive interface between solder and base metallization. In order to quantify this energy, we measured wetting angles of solder drops as well as surface tension of SnPb solders under systematic variation of composition and gaseous flux at different reflow temperatures. For the latter, we used the sessile drop method placing a solder drop on a glas substrate. From the two independent data sets, the important energy of the reactive interface is evaluated based on Young's equation. Remarkably, although both, the tension between the solder and flux and the wetting angle, reveal significant dependence on solder composition. So the adhesion energy reveals distinguished plateaus which are related to different reaction products in contact to the solder. TEM analysis and calculations of phase stabilities show that there is no Cu6Sn5 for high lead concentrations. The experiments confirm a model of reactive wetting by Eustathopoulos.

  16. FY16 Status Report on Development of Integrated EPP and SMT Design Methods

    Energy Technology Data Exchange (ETDEWEB)

    Jetter, R. I. [R.I. Jetter Consulting, Pebble Beach, CA (United States); Sham, T. -L. [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, Y. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-08-01

    The goal of the Elastic-Perfectly Plastic (EPP) combined integrated creep-fatigue damage evaluation approach is to incorporate a Simplified Model Test (SMT) data based approach for creep-fatigue damage evaluation into the EPP methodology to avoid the separate evaluation of creep and fatigue damage and eliminate the requirement for stress classification in current methods; thus greatly simplifying evaluation of elevated temperature cyclic service. The EPP methodology is based on the idea that creep damage and strain accumulation can be bounded by a properly chosen “pseudo” yield strength used in an elastic-perfectly plastic analysis, thus avoiding the need for stress classification. The original SMT approach is based on the use of elastic analysis. The experimental data, cycles to failure, is correlated using the elastically calculated strain range in the test specimen and the corresponding component strain is also calculated elastically. The advantage of this approach is that it is no longer necessary to use the damage interaction, or D-diagram, because the damage due to the combined effects of creep and fatigue are accounted in the test data by means of a specimen that is designed to replicate or bound the stress and strain redistribution that occurs in actual components when loaded in the creep regime. The reference approach to combining the two methodologies and the corresponding uncertainties and validation plans are presented. Results from recent key feature tests are discussed to illustrate the applicability of the EPP methodology and the behavior of materials at elevated temperature when undergoing stress and strain redistribution due to plasticity and creep.

  17. Using computer algebra and SMT-solvers to analyze a mathematical model of cholera propagation

    Science.gov (United States)

    Trujillo Arredondo, Mariana

    2014-06-01

    We analyze a mathematical model for the transmission of cholera. The model is already defined and involves variables such as the pathogen agent, which in this case is the bacterium Vibrio cholera, and the human population. The human population is divided into three classes: susceptible, infectious and removed. Using Computer Algebra, specifically Maple we obtain two equilibrium states: the disease free state and the endemic state. Using Maple it is possible to prove that the disease free state is locally asymptotically stable if and only if R0 1. Using the package Red-Log of the Computer algebra system Reduce and the SMT-Solver Z3Py it is possible to obtain numerical conditions for the model. The formula for the basic reproductive number makes a synthesis with all epidemic parameters in the model. Also it is possible to make numerical simulations which are very illustrative about the epidemic patters that are expected to be observed in real situations. We claim that these kinds of software are very useful in the analysis of epidemic models given that the symbolic computation provides algebraic formulas for the basic reproductive number and such algebraic formulas are very useful to derive control measures. For other side, computer algebra software is a powerful tool to make the stability analysis for epidemic models given that the all steps in the stability analysis can be made automatically: finding the equilibrium points, computing the jacobian, computing the characteristic polynomial for the jacobian, and applying the Routh-Hurwitz theorem to the characteristic polynomial. Finally, using SMT-Solvers is possible to make automatically checks of satisfiability, validity and quantifiers elimination being these computations very useful to analyse complicated epidemic models.

  18. A Study of Solder Alloy Ductility for Cryogenic Applications

    Science.gov (United States)

    Lupinacci, A.; Shapiro, A. A.; Suh, J-O.; Minor, A. M.

    2013-01-01

    For aerospace applications it is important to understand the mechanical performance of components at the extreme temperature conditions seen in service. For solder alloys used in microelectronics, cryogenic temperatures can prove problematic. At low temperatures Sn-based solders undergo a ductile to brittle transition that leads to brittle cracks, which can result in catastrophic failure of electronic components, assemblies and spacecraft payloads. As industrial processes begin to move away from Pb-Sn solder, it is even more critical to characterize the behavior of alternative Sn-based solders. Here we report on initial investigations using a modified Charpy test apparatus to characterize the ductile to brittle transformation temperature of nine different solder systems.

  19. Hybrid microcircuit board assembly with lead-free solders

    Energy Technology Data Exchange (ETDEWEB)

    Vianco, P.T.; Hernandez, C.L.; Rejent, J.A.

    2000-01-11

    An assessment was made of the manufacturability of hybrid microcircuit test vehicles assembled using three Pb-free solder compositions 96.5Sn--3.5Ag (wt.%), 91.84Sn--3.33Ag--4.83Bi, and 86.85Sn--3.15Ag--5.0Bi--5.0Au. The test vehicle substrate was 96% alumina; the thick film conductor composition was 76Au--21Pt--3Pd. Excellent registration between the LCCC or chip capacitor packages and the thick film solder pads was observed. Reduced wetting of bare (Au-coated) LCCC castellations was eliminated by hot solder dipping the I/Os prior to assembly of the circuit card. The Pb-free solders were slightly more susceptible to void formation, but not to a degree that would significantly impact joint functionality. Microstructural damage, while noted in the Sn-Pb solder joints, was not observed in the Pb-free interconnects.

  20. Solder self-assembled, surface micromachined MEMS for micromirror applications and atom trapping

    Science.gov (United States)

    McCarthy, Brian

    Solder self-assembly can be used to expand the versatility of a commercial foundry, like MEMSCAP's PolyMUMPs process. These foundries are attractive for prototyping MEMS as they can offer consistent, low cost fabrication runs by sticking to a single process and integrating multiple customers on each wafer. However, this standardization limits the utility of the process for a given application. Solder self-assembly gives back some of this versatility and expands the envelope of surface micromachining capability in the form of a simple post-process step. Here it is used to create novel micromirrors and micromirror arrays as well as to delve into the field of ultracold atom optics where the utility of MEMS as an enabling technology for atom control is explored. Two types of torsional, electrostatic micromirrors are demonstrated, both of which can achieve +/-10° of rotation. The first is a novel out-of-plane micromirror that can be rotated to a desired angle from the substrate. This integrated, on-chip assembly allows much simpler packaging technology to be used for devices that require a laser beam to be steered off-chip. Planar micromirror arrays that use solder self-assembly to tailor the electrode gap height are also demonstrated. With these designs, no special fabrication techniques are required to achieve large gap heights, and micromirrors with a variety of gap heights can even be fabricated on the same chip. Finally, solder self-assembly is used to explore how complex micro-scale structures can be used to control ultracold atoms. For this study, a MEMS version of a magneto-optical trap, the basis for most ultracold atomic systems, is used to control Rb atoms. In doing so, it provides a path for the successful integration of a number of MEMS devices in these types of systems.

  1. Duality Symmetry and Soldering in Different Dimensions

    CERN Document Server

    Banerjee, R

    1997-01-01

    We develop a systematic method of obtaining duality symmetric actions in different dimensions. This technique is applied for the quantum mechanical harmonic oscillator, the scalar field theory in two dimensions and the Maxwell theory in four dimensions. In all cases there are two such distinct actions. Furthermore, by soldering these distinct actions in any dimension a master action is obtained which is duality invariant under a much bigger set of symmetries than is usually envisaged. The concept of swapping duality is introduced and its implications are discussed. The effects of coupling to gravity are also elaborated. Finally, the extension of the analysis for arbitrary dimensions is indicated.

  2. Electromigration of composite Sn-Ag-Cu solder bumps

    Science.gov (United States)

    Sharma, Ashutosh; Xu, Di Erick; Chow, Jasper; Mayer, Michael; Sohn, Heung-Rak; Jung, Jae Pil

    2015-11-01

    This study investigates the electromigration (EM) behavior of lead free Sn-Ag-Cu (SAC) solder alloys that were reinforced with different types of nanoparticles [Copper-coated carbon nanotubes (Cu/CNT), La2O3, Graphene, SiC, and ZrO2]. The composite solders were bumped on a Cu substrate at 220°C, and the resistance of the bumped solders was measured using a four wire setup. Current aging was carried out for 4 hours at a temperature of 160°C, and an increase in resistance was noted during this time. Of all the composite solders that were studied, La2O3 and SiC reinforced SAC solders exhibited the smallest resistances after current aging. However, the rate of change in the resistance at room temperature was lower for the SiC-reinforced SAC solder. The SAC and Graphene reinforced SAC solder bumps completely failed within 15 - 20 min of these tests. The SiC nanoparticles were reported to possibly entrap the SAC atoms better than other nanoparticles with a lower rate of EM. [Figure not available: see fulltext.

  3. Environmentally compatible solder materials for thick film hybrid assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, F.M.; Vianco, P.T.; Rejent, J.A.; Hernandez, C.L. [Sandia National Labs., Albuquerque, NM (United States). Materials and Process Sciences Center

    1997-02-01

    New soldering materials and processes have been developed over the last several years to address a variety of environmental issues. One of the primary efforts by the electronics industry has involved the development of alternative solders to replace the traditional lead-containing alloys. Sandia National Laboratories is developing such alternative solder materials for printed circuit board and hybrid microcircuit (HMC) applications. This paper describes the work associated with low residue, lead-free soldering of thick film HMC`s. The response of the different materials to wetting, aging, and mechanical test conditions was investigated. Hybrid test vehicles were designed and fabricated with a variety of chip capacitors and leadless ceramic chip carriers to conduct thermal, electrical continuity, and mechanical evaluations of prototype joints. Microstructural development along the solder and thick film interface, after isothermal solid state aging over a range of elevated temperatures and times, was quantified using microanalytical techniques. Flux residues on soldered samples were stressed (temperature-humidity aged) to identify potential corrosion problems. Mechanical tests also supported the development of a solder joint lifetime prediction model. Progress of this effort is summarized.

  4. Time And Temperature Dependent Micromechanical Properties Of Solder Joints For 3D-Package Integration

    Science.gov (United States)

    Roellig, Mike; Meier, Karsten; Metasch, Rene

    2010-11-01

    The recent development of 3D-integrated electronic packages is characterized by the need to increase the diversity of functions and to miniaturize. Currently many 3D-integration concepts are being developed and all of them demand new materials, new designs and new processing technologies. The combination of simulation and experimental investigation becomes increasingly accepted since simulations help to shorten the R&D cycle time and reduce costs. Numerical calculations like the Finite-Element-Method are strong tools to calculate stress conditions in electronic packages resulting from thermal strains due to the manufacturing process and environmental loads. It is essential for the application of numerical calculations that the material data is accurate and describes sufficiently the physical behaviour. The developed machine allows the measurement of time and temperature dependent micromechanical properties of solder joints. Solder joints, which are used to mechanically and electrically connect different packages, are physically measured as they leave the process. This allows accounting for process influences, which may change material properties. Additionally, joint sizes and metallurgical interactions between solder and under bump metallization can be respected by this particular measurement. The measurement allows the determination of material properties within a temperature range of 20° C-200° C. Further, the time dependent creep deformation can be measured within a strain-rate range of 10-31/s-10-81/s. Solder alloys based on Sn-Ag/Sn-Ag-Cu with additionally impurities and joint sizes down to O/ 200 μm were investigated. To finish the material characterization process the material model coefficient were extracted by FEM-Simulation to increase the accuracy of data.

  5. Simulation of thermomechanical fatigue in solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Fang, H.E.; Porter, V.L.; Fye, R.M.; Holm, E.A. [Sandia National Labs., Albuquerque, NM (United States)

    1997-12-31

    Thermomechanical fatigue (TMF) is a very complex phenomenon in electronic component systems and has been identified as one prominent degradation mechanism for surface mount solder joints in the stockpile. In order to precisely predict the TMF-related effects on the reliability of electronic components in weapons, a multi-level simulation methodology is being developed at Sandia National Laboratories. This methodology links simulation codes of continuum mechanics (JAS3D), microstructural mechanics (GLAD), and microstructural evolution (PARGRAIN) to treat the disparate length scales that exist between the macroscopic response of the component and the microstructural changes occurring in its constituent materials. JAS3D is used to predict strain/temperature distributions in the component due to environmental variable fluctuations. GLAD identifies damage initiation and accumulation in detail based on the spatial information provided by JAS3D. PARGRAIN simulates the changes of material microstructure, such as the heterogeneous coarsening in Sn-Pb solder, when the component`s service environment varies.

  6. Albumin-genipin solder for laser tissue welding

    Science.gov (United States)

    Lauto, Antonio; Foster, John; Avolio, Albert; Poole-Warren, Laura

    2004-07-01

    Background. Laser tissue soldering (LTS) is an alternative technique to suturing for tissue repair. One of the major drawbacks of LTS is the weak tensile strength of the solder welds when compared to sutures. In this study, the possibility was investigated for a low cytotoxic crosslinker, acting on amino groups, to enhance the bond strength of albumin solders. Materials and Methods. Solder strips were welded onto rectangular sections of sheep small intestine by a diode laser. The laser delivered in continuous mode mode a power of 170 +/- 10 mW at λ=808 nm, through a multimode optical fiber (core size = 200 μm) to achieve a dose of 10.8 +/- 0.5 J/mg. The solder thickness and surface area were kept constant throughout the experiment (thickness = 0.15 +/- 1 mm, area = 12 +/- 1.2 mm2). The solder incorporated 62% bovine serum albumin, 0.38% genipin, 0.25% indocyanin green dye (IG) and water. Tissue welding was also performed with a similar solder, which did not incorporate genipin, as a control group. The repaired tissue was tested for tensile strength by a calibrated tensiometer. Results. The tensile strength of the "genipin" solder was twice as high as the strength of the BSA solder (0.21 +/- 0.04 N and 0.11 +/- 0.04 N respectively; p~10-15 unpaired t-test, N=30). Discussion. Addition of a chemical crosslinking agent, such as genipin, significantly increased the tensile strength of adhesive-tissue bonds. A proposed mechanism for this enhanced bond strength is the synergistic action of mechanical adhesion with chemical crosslinking by genipin.

  7. Mechanical Reliability of Aged Lead-­Free Solders

    OpenAIRE

    Lewin, Susanne

    2012-01-01

    The usage of lead-­free solder joints in electronic packaging is of greatest concern to the electronic industry due to the health and environmental hazards arising with the use of lead. As a consequence, lead is legally prohibited in the European Union and the industry is aiming to produce lead-free products.            The reliability of solder joints is an important issue as the failure could destroy the whole function of a product. SnAgCu is a commonly used alloy for lead-­free solders. Co...

  8. Solderability and intermetallic compounds formation of Sn-9Zn-xAg lead-free solders wetted on Cu substrate

    Institute of Scientific and Technical Information of China (English)

    CHEN Wenxue; XUE Songbai; WANG Hui; WANG Jianxin; HAN Zongjie

    2009-01-01

    The eutectie Sn-9Zn alloy was doped with Ag (0 wt.%-1 wt.%) to form Sn-9Zn-xAg lead-free solder alloys. The effect of the addition of Ag on the microstructure and solderability of this alloy was investigated and intermetallic compounds (IMCs) formed at the solder/Cu interface were also examined in this study. The results show that, due to the addition of Ag, the microstructure of the solder changes. When the quan-tity of Ag is lower than 0.3 wt.%, the needle-like Zn-rich phase decreases gradually. However, when the quantity of Ag is 0.5 wt.%-1 wt.%, Ag-Zn intermetallic compounds appear in the solder. In particular, adding 0.3 wt.% Ag improves the wetting behavior due to the better oxi-dation resistance of the Sn-9Zn solder. The addition of an excessive amount of Ag will deteriorate the wetting property because the gluti-nosity and fluidity of Sn-9Zn-(0.5, 1)Ag solder decrease. The results also indicate that the addition of Ag to the Sn-Zn solder leads to the pre-cipitation of ε-AgZn_3 from the liquid solder on preformed interracial intermetallics (Cu_5Zn_8). The peripheral AgZn_3, nodular on the Cu_5Zn_8 IMCs layer, is likely to be generated by a peritectic reaction L+γ-Ag_5Zn8→ε-AgZn_3 and the following crystallization of AgZn_3.

  9. Effect of Thick Film Firing Conditions on the Solderability and Structure of Au-Pt-Pd Conductor for Low-Temperature, Co-Fired Ceramic Substrates

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, C.L; Vianco, P.T.

    1999-03-16

    Low-temperature, co-fired ceramics (LTCC) are the substrate material-of-choice for a growing number of multi-chip module (MCM) applications. Unlike the longer-standing hybrid microcircuit technology based upon alumina substrates, the manufacturability and reliability of thick film solder joints on LTCC substrates have not been widely studied. An investigation was undertaken to fully characterize such solder joints. A surface mount test vehicle with Daisy chain electrical connections was designed and built with Dupont{trademark} 951 tape. The Dupont{trademark} 4569 thick film ink (Au76-Pt21 -Pd3 wt.%) was used to establish the surface conductor pattern. The conductor pattern was fired onto the LTCC substrate in a matrix of process conditions that included: (1) double versus triple prints, (2) dielectric frame versus no frame, and (3) three firing temperatures (800 C, 875 C and 950 C). Pads were examined from the test vehicles. The porosity of the thick film layers was measured using quantitative image analysis in both the transverse and short transverse directions. A significant dependence on firing temperature was recorded for porosity. Solder paste comprised of Sn63-Pb37 powder with an RMA flux was screen printed onto the circuit boards. The appropriate components, which included chip capacitors of sizes 0805 up to 2225 and 50 mil pitch, leadless ceramic chip carriers having sizes of 16 I/O to 68 I/O, were then placed on the circuit boards. The test vehicles were oven reflowed under a N{sub 2} atmosphere. The solderability of the thick film pads was also observed to be sensitive to the firing conditions. Solderability appeared to degrade by the added processing steps needed for the triple print and dielectric window depositions. However, the primary factor in solderability was the firing temperature. Solderability was poorer when the firing temperature was higher.

  10. Imposing Constraints from the Source Tree on ITG Constraints for SMT

    Science.gov (United States)

    Yamamoto, Hirofumi; Okuma, Hideo; Sumita, Eiichiro

    In the current statistical machine translation (SMT), erroneous word reordering is one of the most serious problems. To resolve this problem, many word-reordering constraint techniques have been proposed. Inversion transduction grammar (ITG) is one of these constraints. In ITG constraints, target-side word order is obtained by rotating nodes of the source-side binary tree. In these node rotations, the source binary tree instance is not considered. Therefore, stronger constraints for word reordering can be obtained by imposing further constraints derived from the source tree on the ITG constraints. For example, for the source word sequence { a b c d }, ITG constraints allow a total of twenty-two target word orderings. However, when the source binary tree instance ((a b) (c d)) is given, our proposed “imposing source tree on ITG” (IST-ITG) constraints allow only eight word orderings. The reduction in the number of word-order permutations by our proposed stronger constraints efficiently suppresses erroneous word orderings. In our experiments with IST-ITG using the NIST MT08 English-to-Chinese translation track's data, the proposed method resulted in a 1.8-points improvement in character BLEU-4 (35.2 to 37.0) and a 6.2% lower CER (74.1 to 67.9%) compared with our baseline condition.

  11. High temperature solder alloys for underhood applications. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Drewien, C.A.; Yost, F.G.; Sackinger, S. [Sandia National Labs., Albuquerque, NM (United States); Kern, J.; Weiser, M.W. [Univ. of New Mexico (United States). Dept. of Mechanical Engineering

    1995-02-01

    Under a cooperative research and development agreement with General Motors Corporation, lead-free solder systems including the flux, metallization, and solder are being developed for high temperature, underhood applications. Six tin-rich solders, five silver-rich metallizations, and four fluxes were screened using an experimental matrix whereby every combination was used to make sessile drops via hot plate or Heller oven processing. The contact angle, sessile drop appearance, and in some instances the microstructure was evaluated to determine combinations that would yield contact angles of less than 30{degrees}, well-formed sessile drops, and fine, uniform microstructures. Four solders, one metallization, and one flux were selected and will be used for further aging and mechanical property studies.

  12. Method of defence of solder surface from oxidization

    Directory of Open Access Journals (Sweden)

    Kurmashev Sh. D.

    2010-02-01

    Full Text Available Compositions are developed for defence of fusion solder from oxidization on the basis of mixture of glycerin, urea and powders of refractory oxides, carbides (Al2O3, TiO2, SIC, graphite. The offered compositions can be used for defence of fusion of solder from oxidization in the process of soludering and tinning of explorers, and also electric conclusions of elements of radio electronic apparatus by the method of immersion in stationary baths.

  13. Critical evaluations of lead-free solder alloys and performance comparisons

    Energy Technology Data Exchange (ETDEWEB)

    Hitch, T.T.; Palit, K.; Prabhu, A.N. [David Sarnoff Research Center, Princeton, NJ (United States)

    1996-12-31

    This paper discusses the methodology for solder alloy selection, solder preparation processes, test selection, results, and conclusions. The conclusions from this phase of study were that: (1). Solders containing significant amounts of bismuth exhibit poor fatigue life. (2). The Sn-Ag-Cu alloy was the best solder we studied for use as a replacement for Sn-Pb eutectic. A second phase of the work involved detailed study of the Sn-Ag-Cu system with other additions to determine the optimum lead-free solder compositions in terms of melting point, solderability, and mechanical properties.

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

    OpenAIRE

    Liu Mei Lee; Ahmad Azmin Mohamad

    2013-01-01

    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 disc...

  15. Microsurgical anastomosis of sperm duct by laser tissue soldering

    Science.gov (United States)

    Wehner, Martin M.; Teutu-Kengne, Alain-Fleury; Brkovic, Drasko; Henning, Thomas; Klee, Doris; Poprawe, Reinhart; Jakse, Gerhard

    2005-04-01

    Connection of small vessels is usually done by suturing which is very cumbersome. Laser tissue soldering can circumvent that obstacle if a handy procedure can be defined. Our principle approach consists of a bioresorbable hollow stent with an expected degradation time of 3 weeks in combination with laser soldering. The stent is to be fed into the vessel to stabilize both ends and should allow percolation immediately after joining. The stents are made of Poly(D,L-lactid-co-glycolid) and solder is prepared from bovine serum albumin (BSA) doped with Indocyanine green (ICG) as chromophore to increase the absorption of laser light. After insertion, solder is applied onto the outer surface of the vessel and coagulated by laser radiation. The wavelength of 810 nm of a diode laser fits favorably to absorption properties of tissue and solder such that heating up of tissue is limited to prevent from necrosis and wound healing complications. In our study the preparation of stents, the consistency and doping of solder, a beam delivery instrument and the irradiation conditions are worked out. In-vitro tests are carried out on sperm ducts of Sprague-Dowlae (SD) rats. Different irradiation conditions are investigated and a micro-optical system consisting of a lens and a reflecting prism to ensure simultaneous irradiation of front and back side of the vessels tested. Under these conditions, the short-term rupture strength of laser anastomosis revealed as high as those achieved by suturing.

  16. 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.

  17. Creep properties of Pb-free solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Song, H.G.; Morris Jr., J.W.; Hua, F.

    2002-04-01

    Describes the creep behavior of three Sn-rich solders that have become candidates for use in Pb-free solder joints: Sn-3.5Ag, Sn-3Ag-0.5Cu and Sn-0.7Cu. The three solders show the same general behavior when tested in thin joints between Cu and Ni/Au metallized pads at temperatures between 60 and 130 C. Their steady-state creep rates are separated into two regimes with different stress exponents(n). The low-stress exponents range from {approx}3-6, while the high-stress exponents are anomalously high (7-12). Strikingly, the high-stress exponent has a strong temperature dependence near room temperature, increasing significantly as the temperature drops from 95 to 60 C. The anomalous creep behavior of the solders appears to be due to the dominant Sn constituent. Joints of pure Sn have stress exponents, n, that change with stress and temperature almost exactly like those of the Sn-rich solder joints. Research on creep in bulk samples of pure Sn suggests that the anomalous temperature dependence of the stress exponent may show a change in the dominant mechanism of creep. Whatever its source, it has the consequence that conventional constitutive relations for steady-state creep must be used with caution in treating Sn-rich solder joints, and qualification tests that are intended to verify performance should be carefully designed.

  18. Solderability perservative coatings: Electroless tin vs. organic azoles

    Energy Technology Data Exchange (ETDEWEB)

    Artaki, I.; Ray, U.; Jackson, A.M.; Gordon, H.M. [AT and T Bell Labs., Princeton, NJ (United States); Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States)

    1993-07-01

    This paper compares the solderability performance and corrosions ion protection effectiveness of electroless tin coatings versus organic azole films after exposure to a series of humidity and thermal (lead-free solders) cycling conditions. The solderability of immersion tin is directly related to the tin oxide growth on the surface and is not affected by the formation of Sn-Cu intermetallic phases as long as the intermetallic phase is protected by a Sn layer. For a nominal tin thickness of 60{mu}inches, the typical thermal excursions associated with assembly are not sufficient to cause the intermetallic phase to consume the entire tin layer. Exposure to humidity at moderate to elevated temperatures promotes heavy tin oxide formation which leads to solderability loss. In contrast, thin azole films are more robust to humidity exposure; however upon heating in the presence of oxygen, they decompose and lead to severe solderability degradation. Evaluations of lead-free solder pastes for surface mount assembly applications indicate that immersion tin significantly improves the spreading of Sn:Ag and Sn:Bi alloys as compared to azole surface finishes.

  19. Soldering in prosthodontics--an overview, part I.

    Science.gov (United States)

    Byrne, Gerard

    2011-04-01

    The fit of fixed multiunit dental prostheses (FDP), traditionally termed fixed partial dentures (FPDs), is an ongoing problem. Poorly fitting restorations may hasten mechanical failure, due to abutment caries or screw failure. Soldering and welding play an important role in trying to overcome misfit of fixed multiunit prostheses. The term FPD will be used to denote multiunit fixed dental prostheses in this review. This is the first of a series of articles that review the state of the art and science of soldering and welding in relation to the fit of cemented or screw-retained multiunit prostheses. A comprehensive archive of background information and scientific findings is presented. Texts in dental materials and prosthodontics were reviewed. Scientific data were drawn from the numerous laboratory studies up to and including 2009. The background, theory, terminology, and working principles, along with the applied research, are presented. This first article focuses on soldering principles and dimensional accuracy in soldering. There is some discussion and suggestions for future research and development. Soldering may improve dimensional accuracy or reduce the distortion of multiunit fixed prostheses. Many variables can affect the outcome in soldering technique. Research science has developed some helpful guidelines. Research projects are disconnected and limited in scope. © 2011 by The American College of Prosthodontists.

  20. Soldering of Thin Film-Metallized Glass Substrates

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, F.M.; Hernandez, C.L.; Glass, S.J.

    1999-03-31

    The ability to produce reliable electrical and structural interconnections between glass and metals by soldering was investigated. Soldering generally requires premetallization of the glass. As a solderable surface finish over soda-lime-silicate glass, two thin films coatings, Cr-Pd-Au and NiCr-Sn, were evaluated. Solder nettability and joint strengths were determined. Test samples were processed with Sn60-Pb40 solder alloy at a reflow temperature of 210 C. Glass-to-cold rolled steel single lap samples yielded an average shear strength of 12 MPa. Solder fill was good. Control of the Au thickness was critical in minimizing the formation of AuSn{sub 4} intermetallic in the joint, with a resulting joint shear strength of 15 MPa. Similar glass-to-glass specimens with the Cr-Pd-Au finish failed at 16.5 MPa. The NiCr-Sn thin film gave even higher shear strengths of 20-22.5 MPa, with failures primarily in the glass.

  1. Inspection of chemically roughened copper surfaces using optical interferometry and scanning electron microscopy: Establishing a correlation between surface morphology and solderability

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, J.O.; Hosking, F.M.; Guilinger, T.R.; Yost, F.G.; Sorensen, N.R.

    1995-08-01

    Sandia National Laboratories has established a Cooperative Research and Development Agreement with consortium members of the National Center for Manufacturing Sciences (NCMS) to develop fundamental generic technology in printed wiring board materials and surface finishes. We are investigating the effects of surface roughness on the wettability and solderability behavior of several types of copper board finishes to gain insight into surface morphologies that lead to improved solderability. In this paper, we present optical interterometry and scanning electron microscopy results for a variety of chemically-etched copper substrates. Initial testing on six chemical etches demonstrate that surface roughness can be greatly enhanced through chemical etching. Noticeable movements in solder wettability were observed to company increases in roughness.

  2. Characterization of Low-Melting-Point Sn-Bi-In Lead-Free Solders

    Science.gov (United States)

    Li, Qin; Ma, Ninshu; Lei, YongPing; Lin, Jian; Fu, HanGuang; Gu, Jian

    2016-11-01

    Development of lead-free solders with low melting temperature is important for substitution of Pb-based solders to reduce direct risks to human health and the environment. In the present work, Sn-Bi-In solders were studied for different ratios of Bi and Sn to obtain solders with low melting temperature. The microstructure, thermal properties, wettability, mechanical properties, and reliability of joints with Cu have been investigated. The results show that the microstructures of the Sn-Bi-In solders were composed of β-Sn, Bi, and InBi phases. The intermetallic compound (IMC) layer was mainly composed of Cu6Sn5, and its thickness increased slightly as the Bi content was increased. The melting temperature of the solders was around 100°C to 104°C. However, when the Sn content exceeded 50 wt.%, the melting range became larger and the wettability became worse. The tensile strength of the solder alloys and solder joints declined with increasing Bi content. Two fracture modes (IMC layer fracture and solder/IMC mixed fracture) were found in solder joints. The fracture mechanism of solder joints was brittle fracture. In addition, cleavage steps on the fracture surface and coarse grains in the fracture structure were comparatively apparent for higher Bi content, resulting in decreased elongation for both solder alloys and solder joints.

  3. Influences of fine pitch solder joint shape parameters on fatigue life under thermal cycle

    Institute of Scientific and Technical Information of China (English)

    HUANG Chun-yue; WU Zhao-hua; HUANG Hong-yan; ZHOU De-jian

    2005-01-01

    The solder joint reliability of a 0. 5 mm lead pitch, 240-pin quad flat package(QFP) was studied by nonlinear finite element analysis(FEA). The stress/strain distributions within the solder joints and the maximum plastic strain range of the solder joints were determined. Based on the calculated maximum plastic strain range the thermal fatigue life of the solder joints was calculated using Coffin-Manson equation. The influences of shape parameters including volume of solder joint, pad size and stand-off on the thermal fatigue life of the solder joints were also studied. The results show that the stress and strain distribution in the solder joint are not uniform; the interface between the lead and the solder joint is the high stress and strain region; the maximum stress and stain occur at the topmost point where the solder joint intersects with the inner side of the lead. The solder joint cracks should occur firstly at this point and propagate along the interface between the solder and the lead. The solder joint with the pad size of 1.25 mm× 0.35 mm, the stand-off of 0.02 mm and the solder volume of 0. 026 mm3 has longer fatigue life than that of any others. These optimal parameters have been applied in practice to assemble the 240-pin, 0.5 mm pitch QFP.

  4. Solderability of Sn-9Zn-0.5Ag-1In lead-free solder on Cu substrate

    Energy Technology Data Exchange (ETDEWEB)

    Chang, T.-C. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Wang, J.-W. [Department of Environmental and Safety Engineering, Chung Hwa College of Medical Technology, 89 Wen-Hwa 1st Street, Jen-Te, Tainan 71703, Taiwan (China); Wang, M.-C. [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Kaohsiung 80782, Taiwan (China)]. E-mail: mcwang@cc.kuas.edu.tw; Hon, M.-H. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Da-Yeh University, 112 Shan Jean Road, Da-tsuen, Chang-hua, Taiwan (China)

    2006-09-28

    The thermal properties, microstructure corrosion and oxidation resistance of the Sn-9Zn-0.5Ag-1In lead-free solder have been investigated by differential scanning calorimetry, X-ray diffractometry, scanning electron microscopy, energy dispersive spectrometry, potentiostat and thermogravimetry. The Sn-9Zn-0.5Ag-1In solder alloy has a near-eutectic composition, it melts at 187.6 deg. C and the heat of fusion is determined as 71.3 J/g. The Sn-9Zn-0.5Ag-1In solder alloy with a corrosion potential of -1.09 V{sub SCE} and a current density of 9.90 x 10{sup -2} A/cm{sup 2}, shows a better corrosion resistance than that of the Sn-9Zn solder alloy. From the thermogravimetry analysis, the weight gain ratio of the Sn-9Zn solder alloy appears a parabolic relationship at 150 deg. C. The initial oxidation behavior of the Sn-9Zn-0.5Ag and Sn-9Zn-0.5Ag-1In solder alloys also shows a parabolic relationship but the weight gain ratio of them appears a negative linear one after aging at 150 deg. C for 2.5 and 5 h, respectively.

  5. Report on FY15 Alloy 617 SMT Creep-Fatigue Test Results

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanli [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jetter, Robert I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Baird, Seth T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pu, Chao [Univ. of Tennessee, Knoxville, TN (United States); Sham, Sam [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-06-22

    viability of the Alloy 617 Code Case, the use of the current elastic analysis based rules in Subsection NH for the evaluation of strain limits (a precursor for the creep-fatigue rules) and the creep-fatigue rules themselves have been deemed inappropriate for Alloy 617 at temperatures above 650C (Corum and Brass, 1991). The rationale for this exclusion is that at higher temperatures it is not feasible to decouple plasticity and creep, which is the basis for the current simplified rules. This temperature, 650C, is well below the temperature range of interest for this material for the High Temperature Gas Cooled Reactor (HTGR) as well as the VHTR. The only current alternative is, thus, a full inelastic analysis which requires sophisticated material models which have not yet been formulated and verified. To address the prohibition on the use of current methods at very high temperatures, proposed Code rules have been developed which are based on the use of elastic-perfectly plastic (E-PP) analysis methods and which are expected to be applicable to very high temperatures. To provide data to implement the proposed rules and to verify their application, a series of tests have been initiated. One test concept, the Simplified Model Test (SMT), takes into account the stress and strain redistribution in real structures by including representative follow-up characteristics in the test specimen. The correlation parameter between test and design is the elastically calculated strain, and the dependent test variable is the observed cycles to failure. Although the initial priority for the SMT approach is to generate data to support validation of the E-PP Code Case for evaluation of creep-fatigue damage, the broader goal of the SMT approach is to develop a methodology for evaluation of creep fatigue damage which is simpler to implement than the current complex rules and applicable to the full temperature range from ambient conditions to the very high temperature creep regime of 900-950C. Also

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

    Science.gov (United States)

    Chen, Haiyan; Peng, Jianke; Fu, Li; Wang, Xincheng; Xie, Yan

    2016-04-01

    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.

  7. Interaction Kinetics between Sn-Pb Solder Droplet and Au/Ni/Cu Pad

    Institute of Scientific and Technical Information of China (English)

    Fuquan LI; Chunqing WANG; Yanhong TIAN

    2006-01-01

    The interfacial phenomena of the Sn-Pb solder droplet on Au/Ni/Cu pad are investigated. A continuous AuSn2and needle-like AuSn4 are formed at the interface after the liquid state reaction (soldering). The interfacial reaction between the solder and Au layer continues during solid state aging with AuSn4 breaking off from the interface and felling into the solder. The kinetics of Au layer dissolution and diffusion into the solder during soldering and aging is analyzed to elucidate intermetallic formation mechanism at the solder/Au pad interface.The concentration of Au near the solder/pad interface is identified to increase and reach the solubility limit during the period of liquid state reaction. During solid state reaction, the thickening of Au-Sn compound is mainly controlled by element diffusion.

  8. Development of a new Pb-free solder: Sn-Ag-Cu

    Energy Technology Data Exchange (ETDEWEB)

    Miller, C.M.

    1995-02-10

    With the ever increasing awareness of the toxicity of Pb, significant pressure has been put on the electronics industry to get the Pb out of solder. This work pertains to the development and characterization of an alloy which is Pb-free, yet retains the proven positive qualities of current Sn-Pb solders while enhancing the shortcomings of Sn-Pb solder. The solder studied is the Sn-4.7Ag-1.7Cu wt% alloy. By utilizing a variety of experimental techniques the alloy was characterized. The alloy has a melting temperature of 217{degrees}C and exhibits eutectic melting behavior. The solder was examined by subjecting to different annealing schedules and examining the microstructural stability. The effect of cooling rate on the microstructure of the solder was also examined. Overall, this solder alloy shows great promise as a viable alternative to Pb-bearing solders and, as such, an application for a patent has been filed.

  9. A critical review of constitutive models for solders in electronic packaging

    National Research Council Canada - National Science Library

    Chen, Gang; Zhao, Xiaochen; Wu, Hao

    2017-01-01

    .... Because the failure of the whole electronic packaging is often induced by the failure of solders, modeling and simulation of solder joint performance are quite important in ensuring the quality...

  10. Analysis of solderability test methods: predicition model generation for through-hole components

    OpenAIRE

    Woods, Bobby

    2013-01-01

    peer-reviewed In order to achieve a reduction in solderability related defects on electronic components and Printed Circuit Board???s (PCB???s) in electronics manufacturing, preventive controls such as ???Dip & Look??? and ???Wetting Balance??? solderability testing need to be fully optimised to screen out all poor soldering components and PCB???s. Components and PCB???s that pass these tests should solder correctly in volume production. This thesis initially investigates the variations...

  11. Methylene blue solder re-absorption in microvascular anastomoses

    Science.gov (United States)

    Birch, Jeremy F.; Hepplewhite, J.; Frier, Malcolm; Bell, Peter R. F.

    2003-06-01

    Soldered vascular anastomoses have been reported using several chromophores but little is known of the optimal conditions for microvascular anastomosis. There are some indications of the optimal protein contents of a solder, and the effects of methylene blue on anastomotic strength. The effects of varying laser power density in vivo have also been described, showing a high rate of thrombosis with laser power over 22.9Wcm-2. However no evidence exists to describe how long the solder remains at the site of the anastomosis. Oz et al reported that the fibrin used in their study had been almost completely removed by 90 days but without objective evidence of solder removal. In order to address the issue of solder re-absorption from the site of an anastomosis we used radio-labelled albumin (I-125) incorporated into methylene blue based solder. This was investigated in both the situation of the patent and thrombosed anastomosis with anastomoses formed at high and low power. Iodine-125 (half life: 60.2 days) was covalently bonded to porcine albumin and mixed with the solder solution. Radio-iodine has been used over many years to determine protein turnover using either I-125 or I-131. Iodine-125 labelled human albumin is regularly used as a radiopharmaceutical tool for the determination of plasma volume. Radio-iodine has the advantages of not affecting protein metabolism and the label is rapidly excreted after metabolic breakdown. Labelling with chromium (Cr-51) causes protein denaturation and is lost from the protein with time. Labelled albumin has been reported in human studies over a 21-day period, with similar results reported by Matthews. Most significantly McFarlane reported a different rate of catabolism of I-131 and I-125 over a 22-day period. The conclusion from this is that the rate of iodine clearance is a good indicator of protein catabolism. In parallel with the surgery a series of blank standards were prepared with a known mass of solder to correct for isotope

  12. 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...

  13. 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...

  14. Investigation Of Intermetallic Compounds In Sn-Cu-Ni Lead-Free Solders

    Directory of Open Access Journals (Sweden)

    Nagy E.

    2015-06-01

    Full Text Available Interfacial intermetallic compounds (IMC play an important role in Sn-Cu lead-free soldering. The size and morphology of the intermetallic compounds formed between the lead-free solder and the Cu substrate have a significant effect on the mechanical strength of the solder joint.

  15. Experimental Methods in Reduced-gravity Soldering Research

    Science.gov (United States)

    Pettegrew, Richard D.; Struk, Peter M.; Watson, John K.; Haylett, Daniel R.

    2002-01-01

    The National Center for Microgravity Research, NASA Glenn Research Center, and NASA Johnson Space Center are conducting an experimental program to explore the influence of reduced gravity environments on the soldering process. An improved understanding of the effects of the acceleration environment is important to application of soldering during current and future human space missions. Solder joint characteristics that are being considered include solder fillet geometry, porosity, and microstructural features. Both through-hole and surface mounted devices are being investigated. This paper focuses on the experimental methodology employed in this project and the results of macroscopic sample examination. The specific soldering process, sample configurations, materials, and equipment were selected to be consistent with those currently on-orbit. Other apparatus was incorporated to meet requirements imposed by operation onboard NASA's KC-135 research aircraft and instrumentation was provided to monitor both the atmospheric and acceleration environments. The contingent of test operators was selected to include both highly skilled technicians and less skilled individuals to provide a population cross-section that would be representative of the skill mix that might be encountered in space mission crews.

  16. Low-temperature solder for laser tissue welding

    Science.gov (United States)

    Lauto, Antonio; Stewart, Robert B.; Felsen, D.; Foster, John; Poole-Warren, Laura; Poppas, Dix P.

    2003-12-01

    In this study, a two layer (TL) solid solder was developed with a fixed thickness to minimize the difference in temperature across the solder (ΔT) and to weld at low temperature. Solder strips comprising two layers (65% albumin, 35% water) were welded onto rectangular sections of dog small intestine by a diode laser (λ = 808 nm). The laser delivered a power of 170 +/- 10 mW through an optical fiber (spot size approximately 1 mm) for 100 seconds. A solder layer incorporated also a dye (carbon black, 0.25%) to absorb the laser radiation. A thermocouple and an infrared thermometer system recorded the temperatures at the tissue interface and at the external solder surface, during welding. The repaired tissue was tested for tensile strength by a calibrated tensiometer. The TL strips were able to minimize ΔT (12 +/- 4°C) and control the temperature at tissue-interface. The strips fused on tissue at 55=70°C for tissue repair, which cause more irreversible thermal damage.

  17. Creep characterization of solder bumps using nanoindentation

    Science.gov (United States)

    Du, Yingjie; Liu, Xiao Hu; Fu, Boshen; Shaw, Thomas M.; Lu, Minhua; Wassick, Thomas A.; Bonilla, Griselda; Lu, Hongbing

    2017-08-01

    Current nanoindentation techniques for the measurement of creep properties are applicable to viscoplastic materials with negligible elastic deformations. A new technique for characterization of creep behavior is needed for situations where the elastic deformation plays a significant role. In this paper, the effect of elastic deformation on the determination of creep parameters using nanoindentation with a self-similar nanoindenter tip is evaluated using finite element analysis (FEA). It is found that the creep exponent measured from nanoindentation without taking into account of the contribution of elastic deformation tends to be higher than the actual value. An effective correction method is developed to consider the elastic deformation in the calculation of creep parameters. FEA shows that this method provides accurate creep exponent. The creep parameters, namely the creep exponent and activation energy, were measured for three types of reflowed solder bumps using the nanoindentation method. The measured parameters were verified using FEA. The results show that the new correction approach allows extraction of creep parameters with precision from nanoindentation data.

  18. 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.

  19. Effects of Solder Temperature on Pin Through-Hole during Wave Soldering: Thermal-Fluid Structure Interaction Analysis

    Science.gov (United States)

    Abdul Aziz, M. S.; Abdullah, M. Z.; Khor, C. Y.

    2014-01-01

    An efficient simulation technique was proposed to examine the thermal-fluid structure interaction in the effects of solder temperature on pin through-hole during wave soldering. This study investigated the capillary flow behavior as well as the displacement, temperature distribution, and von Mises stress of a pin passed through a solder material. A single pin through-hole connector mounted on a printed circuit board (PCB) was simulated using a 3D model solved by FLUENT. The ABAQUS solver was employed to analyze the pin structure at solder temperatures of 456.15 K (183°C) analysis. In addition, an experiment was conducted to measure the temperature difference (ΔT) between the top and the bottom of the pin. Analysis results showed that an increase in temperature increased the structural displacement and the von Mises stress. Filling time exhibited a quadratic relationship to the increment of temperature. The deformation of pin showed a linear correlation to the temperature. The ΔT obtained from the simulation and the experimental method were validated. This study elucidates and clearly illustrates wave soldering for engineers in the PCB assembly industry. PMID:25225638

  20. 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.

  1. Horizon Shells and BMS-like Soldering Transformations

    CERN Document Server

    Blau, Matthias

    2015-01-01

    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 ...

  2. Bosonisation and Duality Symmetry in the Soldering Formalism

    CERN Document Server

    Banerjee, R

    1998-01-01

    We develop a technique that solders the dual aspects of some symmetry. Using this technique it is possible to combine two theories with such symmetries to yield a new effective theory. Some applications in two and three dimensional bosonisation are discussed. In particular, it is shown that two apparently independent three dimensional massive Thirring models with same coupling but opposite mass signatures, in the long wavelegth limit, combine by the process of bosonisation and soldering to yield an effective massive Maxwell theory. Similar features also hold for quantum electrodynamics in three dimensions. We also provide a systematic derivation of duality symmetric actions and show that the soldering mechanism leads to a master action which is duality invariant under a bigger set of symmetries than is usually envisaged. The concept of duality swapping is introduced and its implications are analysed. The example of electromagnetic duality is discussed in details.

  3. Corrosion Issues in Solder Joint Design and Service

    Energy Technology Data Exchange (ETDEWEB)

    VIANCO,PAUL T.

    1999-11-24

    Corrosion is an important consideration in the design of a solder joint. It must be addressed with respect to the service environment or, as in the case of soldered conduit, as the nature of the medium being transported within piping or tubing. Galvanic-assisted corrosion is of particular concern, given the fact that solder joints are comprised of different metals or alloy compositions that are in contact with one-another. The (thermodynamic) potential for corrosion to take place in a particular environment requires the availability of the galvanic series for those conditions and which includes the metals or alloys in question. However, the corrosion kinetics, which actually determine the rate of material loss under the specified service conditions, are only available through laboratory evaluations or field data that are found in the existing literature or must be obtained by in-house testing.

  4. Process characterization and control of hand-soldered printed wiring assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Cheray, D.L.; Mandl, R.G.

    1993-09-01

    A designed experiment was conducted to characterize the hand soldering process parameters for manufacturing printed wiring assemblies (PWAs). Component tinning was identified as the most important parameter in hand soldering. After tinning, the soldering iron tip temperature of 700{degrees}F and the choice of operators influence solder joint quality more than any other parameters. Cleaning and flux/flux core have little impact on the quality of the solder joint. The need for component cleaning prior to assembly must be evaluated for each component.

  5. The impact of process parameters on gold elimination from soldered connector assemblies

    Energy Technology Data Exchange (ETDEWEB)

    VIANCO,PAUL T.; KILGO,ALICE C.

    2000-02-02

    Minimizing the likelihood of solder joint embrittlement in connectors is realized by reducing or eliminating retained Au plating and/or Au-Sn intermetallic compound formation from the assemblies. Gold removal is performed most effectively by using a double wicking process. When only a single wicking procedure can be used, a higher soldering temperature improves the process of Au removal from the connector surfaces and to a nominal extent, removal of Au-contaminated solder from the joint. A longer soldering time did not appear to offer any appreciable improvement toward removing the Au-contaminated solder from the joint. Because the wicking procedure was a manual process, it was operator dependent.

  6. A new active solder for joining electronic components

    Energy Technology Data Exchange (ETDEWEB)

    SMITH,RONALD W.; VIANCO,PAUL T.; HERNANDEZ,CYNTHIA L.; LUGSCHEIDER,E.; RASS,I.; HILLEN,F.

    2000-05-11

    Electronic components and micro-sensors utilize ceramic substrates, copper and aluminum interconnect and silicon. The joining of these combinations require pre-metallization such that solders with fluxes can wet such combinations of metals and ceramics. The paper will present a new solder alloy that can bond metals, ceramics and composites. The alloy directly wets and bonds in air without the use flux or premetallized layers. The paper will present typical processing steps and joint microstructures in copper, aluminum, aluminum oxide, aluminum nitride, and silicon joints.

  7. Lead Free Solder Joint Thermal Condition in Semiconductor Packaging

    Directory of Open Access Journals (Sweden)

    M. N. Harif

    2010-01-01

    Full Text Available Problem statement: Solder joints are responsible for both electrical and mechanical connections. Solder does not have adequate ductility to ensure the repeated relative displacements due to the mismatch between expansion coefficients of the chip carrier and the circuit board. Solder material plays a crucial role to provide the necessary electrical and mechanical interconnections in an electronic assembly. Finding a technique to increase the service life of future connections is not the total solution. A method must be developed for predicting the remaining service life of many joints already in use. Approach: The effect of High Temperature Storage (HTS on lead free solder joint material for ball grid array application using pull test method is studied in this study. Some statistical analysis base on the pull test data also discussed. Three samples of different lead free solder joint material were selected in this experiment namely Sn3.8Ag0.7Cu (SAC387, Sn2.3Ag0.08Ni0.01Co (SANC and Sn3.5Ag. After the thermal condition test, all the lead free solder joint material samples were tested using Dage 4000 pull test machine. Each pull test will be 5 units and each unit contains 8 balls. Results: The mean pull strength for high temperature storage is 2847.66, 2628.20 and 2613.79 g for Sn3.5Ag, SANC and SAC387, respectively. Thus, Sn3.5Ag shows a significantly better solder joint performance in terms of joint strength compare to SANC and SAC387. Hence, Intermetallic Compound (IMC thicknesses were measured after cross-sectioning. Sample size for cross-sectioning was 3 units per read point, 2 balls per unit and 3 maximum IMC peaks per ball and the measurement using high power scope of 100x and Image Analyzer software to measure the IMC thickness. For high temperature storage, result show that the mean IMC thicknesses for SAC387, SANC and Sn3.5Ag are 3.9139, 2.3111 and 2.3931 µm. Conclusion/Recommendations: It was found that IMC thickness for SANC and Sn3

  8. Development of materials design tool and its application in Pb-free micro-solders in electronic package

    Institute of Scientific and Technical Information of China (English)

    OHNUMA; Ikuo; KAINUMA; Ryosuke; ISHIDA; Kiyohito; CHANG; Austin; Y.

    2010-01-01

    A materials design tool for developing Pb-free soldering alloys in electronic package was developed based on comprehensive experimental data of phase equilibria and thermodynamic properties data accumulated with the CALPHAD (calculation of phase diagrams) method and contains 10 elements,namely,Ag,Au,Bi,Cu,In,Ni,Sb,Sn,Zn and Pb.It can handle the calculation of phase diagrams in all combinations of these elements and all composition ranges.In addition,based on this tool,the liquidus,solidus,phase fractions and constitutions,equilibrium and non-equilibrium solidification behavior,surface tension and viscosity of liquid,diffusion reactions and microstructural evolution,etc.can be predicted.Typical examples of the calculation and application of this tool are presented.The design tool is expected to be a powerful tool for the development of Pb-free solders,as well as for promoting the understanding of the interfacial phenomena between Cu substrate and Pb-free solders in electronic packaging technology.

  9. High-temperature lead-free solder alternatives

    DEFF Research Database (Denmark)

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

    2011-01-01

    For lead-free solders in the high-temperature regime, unfortunately, a limited number of alloying systems are available. These are Bi based alloys, gold involving alloys and Zn–Al based alloys. Based on these systems, possible candidate alloys were designed to have a melting range between 270°C a...

  10. Thermomechanical fatigue damage evolution in SAC solder joints

    NARCIS (Netherlands)

    Matin, M. A.; Vellinga, W. P.; D Geers, M. G.

    2007-01-01

    Thermornechanical fatigue in lab-type Sn-Ag-Cu solder interconnections between two copper plates has been investigated under cyclic thermal loading within a number of temperature ranges. Fatigue mechanisms have been studied using optical and scanning electron microscopy. Among the various fatigue me

  11. Horizon shells and BMS-like soldering transformations

    Science.gov (United States)

    Blau, Matthias; O'Loughlin, Martin

    2016-03-01

    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.

  12. Thermomechanical fatigue damage evolution in SAC solder joints

    NARCIS (Netherlands)

    Matin, M. A.; Vellinga, W. P.; D Geers, M. G.

    2007-01-01

    Thermornechanical fatigue in lab-type Sn-Ag-Cu solder interconnections between two copper plates has been investigated under cyclic thermal loading within a number of temperature ranges. Fatigue mechanisms have been studied using optical and scanning electron microscopy. Among the various fatigue me

  13. Printed-Circuit-Board Soldering Training for Group IV Personnel.

    Science.gov (United States)

    Hooprich, E. A.; Matlock, E. W.

    As part of a larger program to determine which Navy skills can be learned by lower aptitude personnel, and which methods and techniques would be most effective, an experimental course in printed circuit board soldering was given to 186 Group IV students in 13 classes. Two different training approaches--one stressing instructor guidance and the…

  14. 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.

  15. Roles of interfacial reaction on mechanical properties of solder interfaces

    Science.gov (United States)

    Liu, Pilin

    This study investigated roles of interfacial reaction in fracture and fatigue of solder interconnects. The interfacial reaction phases in the as-reflowed and after aging were examined by cross-sectional transmission electron microscopy (TEM) while interfacial mechanical properties were determined from a flexural peel fracture mechanics technique. Because of their widespread uses in microelectronic packaging, SnPb solder interfaces, and Bi-containing Pb-free solder interfaces were chosen as the subjects of this study. In the interfacial reaction study, we observed a complicated micro structural evolution during solid-state aging of electroless-Ni(P)/SnPb solder interconnects. In as-reflowed condition, the interfacial reaction produced Ni3Sn 4 and P-rich layers. Following overaging, the interfacial microstructure degenerated into a complex multilayer structure consisting of multiple layers of Ni-Sn compounds and transformed Ni-P phases. In SnPb solder interfacial system, fatigue study showed that the overaging of the high P electroless Ni-P/SnPb interconnects resulted in a sharp reduction in the fatigue resistance of the interface in the high crack growth rate regime. Fracture mechanism analysis indicated that the sharp drop in fatigue resistance was triggered by the brittle fracture of the Ni3Sn2 intermetallic phase developed at the overaged interface. The fatigue behavior was strongly dependent on P concentration in electroless Ni. Kirkendall voids were found in the interfacial region after aging, but they did not cause premature fracture of the solder interfaces. In Bi-containing solder interfacial system, we found that Bi segregated to the Cu-intermetallic interface during aging in SnBi/Cu interconnect. This caused serious embrittlement of Sn-Bi/Cu interface. Further aging induced numerous voids along the Cu3Sn/Cu interface. These interfacial voids were different from Kirkendall voids. Their formation was explained on basis of vacancy condensation at the

  16. 应用FCM算法的成组SMT PCB的装配线%Grouping SMT PCB Assembly using FCM Algorithm

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This is a further development work on grouping of printed circuit boards (PCBs)For Surface Mount Assembly in the electronic industry.The arrangement of PCBsamong several surface mount machine lines in a typical kind of group technology (GT)problem./From,literatures,there are various clustering techniques developed to solve the clustering problems .In This paper,fuzzy c-means clustering (FCM) is used to solve the PCBs GROUPING PROBLEM,Applying them in a real problem compares the results of the two method.The result shows that there should be a systematic metold to arrange the scheduling of PCB assemblies in electronic industry to improve the operations planning process.

  17. FORMATION AND CHANGE OF AuSn4 COMPOUNDS AT INTERFACE BETWEEN PBGA SOLDER BALL AND Au/Ni/Cu METALLIZATION DURING LASER AND INFRA-RED REFLOW SOLDERING

    Institute of Scientific and Technical Information of China (English)

    Y.H.Tian; C.Q.Wang

    2004-01-01

    Interactions between 63Sn37Pb solder and PBGA metallization(Au/Ni/Cu)during laser and infrared reflow soldering were studied.During laser refow soldering process,a thin layer of AuSn4 was observed at the interface of the solder bumps,its morphology was strongly dependent on the laser reflow power and heating time.The solder bumps formed by the first laser reflow was refowed again to form the solder joints.The AuSn4 compounds formed in the first laser reflow process dissolved into the bulk solder after the secondary infrared reflow process.The needle-like AuSn4 changed into rodlike,and distributed inside the solder near the solder/pad interface.

  18. Large area photonic flash soldering of thin chips on flex foils for flexible electronic systems: In situ temperature measurements and thermal modelling

    Science.gov (United States)

    van den Ende, D. A.; Hendriks, R.; Cauchois, R.; Groen, W. A.

    2014-11-01

    In this work photonic energy from a high power xenon flash lamp is used for soldering thin chips on polyimide and polyester foil substrates using standard Sn-Ag-Cu lead free alloys. The absorption of the xenon light pulse leads to rapid heating of components and tracks up to temperatures above the solder melting temperature, while the temperature in the organic foil substrates remains low. Due to its high transparency the temperature in the delicate polyester foil remains low enough to avoid damage and allows fast soldering with standard lead-free alloys. The technology is fast and could be applied in-line in roll-to-roll fabrication of flexible electronics. In situ temperature measurements were performed and compared to finite element model predictions of the temperature in the chip during and after application of the photonic pulse. The accuracy of the model is within 10°C for the tested samples, which allows it to be used in developing photonic flash soldering compatible circuit designs. [Figure not available: see fulltext.

  19. Electromigration Behaviors of Cu Reinforced Sn-3.5Ag Composite Solder Joints

    Science.gov (United States)

    Wang, Yan; Han, Jing; Ma, Limin; Zuo, Yong; Guo, Fu

    2016-09-01

    The composite approach, by incorporating small amounts of reinforcement particles in the solder matrix, has proven to be one of the effective ways to improve the reliability of solder joints. The effects of Cu addition on electromigration were investigated in this study by incorporating 2% volume fraction Cu particles into Sn-3.5Ag eutectic solder paste by the in situ process. The one-dimensional solder joints, designed to prevent the current crowding effect, were stressed under a constant current density of 104 A/cm2 at room temperature, and the temperature of the sample could reach 105 ± 5°C due to the Joule heating effect. Doping 2 vol.% Cu was found to retard the electromigration phenomenon effectively. After electric current stressing for 528 h, the growth rate of an interfacial intermetallic compound (IMC) layer at the anode decreased 73% in contrast to that of Sn-3.5Ag solder joints, and the IMC layer at the cathode was almost unchanged. The polarization effect of Cu reinforced composite solder joints was also apparently mitigated. In addition, the surface damage of the composite solder joints was relieved by incorporating 2 vol.% Cu particles. Compared to Sn-3.5Ag solder joints, which had protruded Cu6Sn5 and wrinkles of Sn-solder matrix on the surface, the solder joints with Cu addition had a more even surface.

  20. Electromigration Behaviors of Cu Reinforced Sn-3.5Ag Composite Solder Joints

    Science.gov (United States)

    Wang, Yan; Han, Jing; Ma, Limin; Zuo, Yong; Guo, Fu

    2016-12-01

    The composite approach, by incorporating small amounts of reinforcement particles in the solder matrix, has proven to be one of the effective ways to improve the reliability of solder joints. The effects of Cu addition on electromigration were investigated in this study by incorporating 2% volume fraction Cu particles into Sn-3.5Ag eutectic solder paste by the in situ process. The one-dimensional solder joints, designed to prevent the current crowding effect, were stressed under a constant current density of 104 A/cm2 at room temperature, and the temperature of the sample could reach 105 ± 5°C due to the Joule heating effect. Doping 2 vol.% Cu was found to retard the electromigration phenomenon effectively. After electric current stressing for 528 h, the growth rate of an interfacial intermetallic compound (IMC) layer at the anode decreased 73% in contrast to that of Sn-3.5Ag solder joints, and the IMC layer at the cathode was almost unchanged. The polarization effect of Cu reinforced composite solder joints was also apparently mitigated. In addition, the surface damage of the composite solder joints was relieved by incorporating 2 vol.% Cu particles. Compared to Sn-3.5Ag solder joints, which had protruded Cu6Sn5 and wrinkles of Sn-solder matrix on the surface, the solder joints with Cu addition had a more even surface.

  1. Science Education in Nigeria: An Examination of People's Perceptions about Female Participation in Science, Mathematics and Technology

    Science.gov (United States)

    Ogunjuyigbe, Peter O.; Ojofeitimi, Ebenezer O.; Akinlo, Ambrose

    2006-10-01

    The paper brings to focus people's perception about female involvement in science, mathematics and technology (SMT). Data for the study were obtained from a survey conducted in March, 2005 in two Local Government Areas of Osun state, Southwest Nigeria. The paper reveals that: (i) about 57% of household heads, 45.6% of mothers and 57.6% of the children are of the opinion that both boys and girls are given equal right to SMT education (ii) social forces play an important role in determining people's attitude to SMT (iii) though, parents and stakeholders perceptions about girls' participation in some professions is changing, however, socio-cultural and economic factors still determine which sex to encourage to read SMT.

  2. Effects of particle size on the mechanical properties of particle-reinforced Sn-Ag composite solder joint

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Particulate size has significant influenced on the mechanical properties of particle-reinforced composite solder joints. In this current research, Cu or Ni reinforcement particles were mechanically added to the Sn-3.5Ag eutectic solder, and the effects of the particle size on the mechanical properties of particle-reinforced composite solder joint were systematically studied. This investigation touched on how mechanical properties of the solder joints are affected by particles size. A quantitative formula was set up to correlate the mechanical property of the solder joint with particle size in different processing conditions. Besides, the fracture mechanism of the composite solder joint was analyzed.

  3. The Mechanical Behavior of Sn-Ag4 Solder Joints Subjected to Thermal Cycling

    Institute of Scientific and Technical Information of China (English)

    CHENGuohai; MAJusheng

    2004-01-01

    The method of mount strain gages is used to measure the stress/strain hysteresis loops of the solder joints under thermal cycling. The results show that different solders have different loops; the shape of the loops will change less, and finally become a line along with the thermal cycle increase. The shear module decreases along with the thermal cycling process. But the creep index of the solder joints is not sensitive to the cycling process,which fluctuates between 5 and 7. Because the elements of the solder and matrix materials diffuse during the process, the voids induced in the solder joints expand. The expansion of the voids will lead to the crystal lattice aberrance of solder crystal.

  4. Root Cause Investigation of Lead-Free Solder Joint Interfacial Failures After Multiple Reflows

    Science.gov (United States)

    Li, Yan; Hatch, Olen; Liu, Pilin; Goyal, Deepak

    2017-03-01

    Solder joint interconnects in three-dimensional (3D) packages with package stacking configurations typically must undergo multiple reflow cycles during the assembly process. In this work, interfacial open joint failures between the bulk solder and the intermetallic compound (IMC) layer were found in Sn-Ag-Cu (SAC) solder joints connecting a small package to a large package after multiple reflow reliability tests. Systematic progressive 3D x-ray computed tomography experiments were performed on both incoming and assembled parts to reveal the initiation and evolution of the open failures in the same solder joints before and after the reliability tests. Characterization studies, including focused ion beam cross-sections, scanning electron microscopy, and energy-dispersive x-ray spectroscopy, were conducted to determine the correlation between IMC phase transformation and failure initiation in the solder joints. A comprehensive failure mechanism, along with solution paths for the solder joint interfacial failures after multiple reflow cycles, is discussed in detail.

  5. 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 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.

  6. Reaction of Liquid Sn-Ag-Cu-Ce Solders with Solid Copper

    Science.gov (United States)

    Chriaštel'Ová, J.; Rízeková Trnková, L.; Pocisková Dimová, K.; Ožvold, M.

    2011-09-01

    Small amounts of the rare-earth element Ce were added to the Sn-rich lead-free eutectic solders Sn-3.5Ag-0.7Cu, Sn-0.7Cu, and Sn-3.5Ag to improve their properties. The microstructures of the solders without Ce and with different amounts (0.1 wt.%, 0.2 wt.%, and 0.5 wt.%) of Ce were compared. The microstructure of the solders became finer with increasing Ce content. Deviation from this rule was observed for the Sn-Ag-Cu solder with 0.2 wt.% Ce, and for the Sn-0.7Cu eutectic alloy, which showed the finest microstructure without Ce. The melting temperatures of the solders were not affected. The morphology of intermetallic compounds (IMC) formed at the interface between the liquid solders and a Cu substrate at temperatures about 40°C above the melting point of the solder for dipping times from 2 s to 256 s was studied for the basic solder and for solder with 0.5 wt.% Ce addition. The morphology of the Cu6Sn5 IMC layer developed at the interface between the solders and the substrate exhibited the typical scallop-type shape without significant difference between solders with and without Ce for the shortest dipping time. Addition of Ce decreased the thickness of the Cu6Sn5 IMC layer only at the Cu/Sn-Ag-Cu solder interface for the 2-s dipping. A different morphology of the IMC layer was observed for the 256-s dipping time: The layers were less continuous and exhibited a broken relief. Massive scallops were not observed. For longer dipping times, Cu3Sn IMC layers located near the Cu substrate were also observed.

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

    OpenAIRE

    Heinemann, D.; S. Knabner; Baumgarten, D.

    2016-01-01

    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. ...

  8. 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

    Presence of moisture in a printed circuit board (PCB) laminate, typically made of glass fibres reinforced epoxy polymer, significantly influences the electrical functionality in various ways and causes problems during soldering process. This paper investigates the water uptake of laminates coated...... 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...

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

    DEFF Research Database (Denmark)

    and mechanical properties of these potential candidate alloys with respect to the currently used high-lead content solders is made. Finally, the paper presents the superior characteristics as well as some drawbacks of these proposed high-temperature lead-free solder alternatives....... 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...

  10. Creep Behavior of Lead-Free Sn-Ag-Cu + Ni-Ge Solder Alloys

    Science.gov (United States)

    Hidaka, N.; Watanabe, H.; Yoshiba, M.

    2009-05-01

    We developed a new lead-free solder alloy, an Sn-Ag-Cu base to which a small amount of Ni and Ge is added, to improve the mechanical properties of solder alloys. We examined creep deformation in bulk and through-hole (TH) form for two lead-free solder alloys, Sn-3.5Ag-0.5Cu-Ni-Ge and Sn-3.0Ag-0.5Cu, at elevated temperatures, finding that the creep rupture life of the Sn-3.5Ag-0.5Cu-Ni-Ge solder alloy was over three times better than that of the Sn-3.0Ag-0.5Cu solder at 398 K. Adding Ni to the solder appears to make microstructural development finer and more uniform. The Ni added to the solder readily combined with Cu to form stable intermetallic compounds of (Cu, Ni)6Sn5 capable of improving the creep behavior of solder alloys. Moreover, microstructural characterization based on transmission electron microscopy analyses observing creep behavior in detail showed that such particles in the Sn-3.5Ag-0.5Cu-Ni-Ge solder alloy prevent dislocation and movement.

  11. Joining of Bi-2212 high- Tc superconductors and metals using indium solders

    Science.gov (United States)

    Oh, S. Y.; Kim, H. R.; Jeong, Y. H.; Hyun, O. B.; Kim, C. J.

    2007-10-01

    BSCCO tubes can be used as a base material for switching devices such as superconducting fault current limiters (SFCLs) that prevent an electrical problem from occurring in an electrical power system. To apply an BSCCO bulk tube to a switching device, the superconducting tube has to be joined with a metallic part to by the over current to the metal part when the FCL is quenched. In this study, joining between Cu-Ni alloy and BSCCO was accomplished by soldering using In-Sn and In-Bi solders. Additionally, an Sn-Ag-Cu/In-Bi solder was used for the soldering of a different kind. For a better joining of the BSCCO superconductor with the In-Bi solder, the surface of the BSCCO was pre-coated with Ag by electro-plating. From the experiments, an intermetallic compound (IMC) of AgxIny chain was observed to be mainly formed from In-Sn and In-Bi soldering process. In case of the soldering of a different kind, IMC of AgxIny and CuxSny was also developed. Finally, we confirmed that the properties of soldering were enhanced by Sn-Ag-Cu/In-Bi twice-soldering process.

  12. Joining of Bi-2212 high-T{sub c} superconductors and metals using indium solders

    Energy Technology Data Exchange (ETDEWEB)

    Oh, S.Y. [Nuclear Nanomaterials Development Laboratory, Korea Atomic Energy Research Institute (KAERI), 150 Dukjin-dong, Yusong-gu, Daejeon 305-353 (Korea, Republic of); Kim, H.R.; Jeong, Y.H.; Hyun, O.B. [Superconductivity and Applications Group, Korea Electric Power Research Institute (KEPRI), Daejeon 305-380 (Korea, Republic of); Kim, C.J. [Nuclear Nanomaterials Development Laboratory, Korea Atomic Energy Research Institute (KAERI), 150 Dukjin-dong, Yusong-gu, Daejeon 305-353 (Korea, Republic of)], E-mail: cjkim2@kaeri.re.kr

    2007-10-01

    BSCCO tubes can be used as a base material for switching devices such as superconducting fault current limiters (SFCLs) that prevent an electrical problem from occurring in an electrical power system. To apply an BSCCO bulk tube to a switching device, the superconducting tube has to be joined with a metallic part to by the over current to the metal part when the FCL is quenched. In this study, joining between Cu-Ni alloy and BSCCO was accomplished by soldering using In-Sn and In-Bi solders. Additionally, an Sn-Ag-Cu/In-Bi solder was used for the soldering of a different kind. For a better joining of the BSCCO superconductor with the In-Bi solder, the surface of the BSCCO was pre-coated with Ag by electro-plating. From the experiments, an intermetallic compound (IMC) of Ag{sub x}In{sub y} chain was observed to be mainly formed from In-Sn and In-Bi soldering process. In case of the soldering of a different kind, IMC of Ag{sub x}In{sub y} and Cu{sub x}Sn{sub y} was also developed. Finally, we confirmed that the properties of soldering were enhanced by Sn-Ag-Cu/In-Bi twice-soldering process.

  13. An Evaluation of Prototype Circuit Boards Assembled with a Sn-Ag Bi Solder

    Energy Technology Data Exchange (ETDEWEB)

    ARTAKI,I.; RAY,U.; REJENT,JEROME A.; VIANCO,PAUL T.

    1999-09-01

    An evaluation was performed which examined the aging of surface mount solder joints assembled with 91.84Sn-3.33Ag-4.83Bi solder. Defect analysis of the as-fabricated test vehicles revealed excellent solderability, good package alignment, and a minimum number of voids. Continuous DC electrical monitoring of the solder joints did not reveal opens during as many as 10,000 thermal cycles (0 C, 100 C). The solder joints exhibited no significant degradation through 2500 cycles, based upon an absence of microstructural damage and sustained shear and pull strengths of chip capacitors and J-leaded solder joints, respectively. Thermal cycles of 5000 and 10,000 resulted in some surface cracking of the solder fillets and coatings. In a few cases, deeper cracks were observed in the thinner reaches of several solder fillets. There was no deformation or cracking in the solder located in the gap between the package I/O and the circuit board pad nor in the interior of the fillets, both locations that would raise concerns of joint mechanical integrity. A drop in the chip capacitor shear strength was attributed to crack growth near the top of the fillet.

  14. Solderable and electroplatable flexible electronic circuit on a porous stretchable elastomer

    Science.gov (United States)

    Jeong, Gi Seok; Baek, Dong-Hyun; Jung, Ha Chul; Song, Ji Hoon; Moon, Jin Hee; Hong, Suck Won; Kim, In Young; Lee, Sang-Hoon

    2012-07-01

    A variety of flexible and stretchable electronics have been reported for use in flexible electronic devices or biomedical applications. The practical and wider application of such flexible electronics has been limited because commercial electronic components are difficult to be directly integrated into flexible stretchable electronics and electroplating is still challenging. Here, we propose a novel method for fabricating flexible and stretchable electronic devices using a porous elastomeric substrate. Pressurized steam was applied to an uncured polydimethylsiloxane layer for the simple and cost-effective production of porous structure. An electroplated nickel anchor had a key role in bonding commercial electronic components on elastomers by soldering techniques, and metals could be stably patterned and electroplated for practical uses. The proposed technology was applied to develop a plaster electrocardiogram dry electrode and multi-channel microelectrodes that could be used as a long-term wearable biosignal monitor and for brain signal monitoring, respectively.

  15. Nano Coated Lead Free Solders for Sustainable Electronic Waste Management

    Directory of Open Access Journals (Sweden)

    K. Arun Vasantha Geethan

    Full Text Available ABSTRACT Lead has been used in a wide range of applications, but in the past decades it became clear that its high toxicity could cause various problems. Studies indicate that exposure to high concentrations of lead can cause harmful damages to humans. To eliminate the usage of lead in electronic products as an initiative towards electronic waste management (e waste, lead free solders were produced with suitable methods by replacing lead. But lead free solders are not preferred as a substitute of lead because they are poor in their mechanical properties such as tensile strength, shear strength and hardness which are ultimately required for a material to resist failure.Nano-Structured materials and coatings offer the potential for Vital improvements in engineering properties based on improvements in physical and mechanical properties resulting from reducing micro structural features by factors of 100 to 1000 times compared to current engineering materials.

  16. Morphology and Shear Strength of Lead-Free Solder Joints with Sn3.0Ag0.5Cu Solder Paste Reinforced with Ceramic Nanoparticles

    Science.gov (United States)

    Yakymovych, A.; Plevachuk, Yu.; Švec, P.; Švec, P.; Janičkovič, D.; Šebo, P.; Beronská, N.; Roshanghias, A.; Ipser, H.

    2016-12-01

    To date, additions of different oxide nanoparticles is one of the most widespread procedures to improve the mechanical properties of metals and metal alloys. This research deals with the effect of minor ceramic nanoparticle additions (SiO2, TiO2 and ZrO2) on the microstructure and mechanical properties of Cu/solder/Cu joints. The reinforced Sn3.0Ag0.5Cu (SAC305) solder alloy with 0.5 wt.% and 1.0 wt.% of ceramic nanoparticles was prepared through mechanically stirring. The microstructure of as-solidified Cu/solder/Cu joints was studied using scanning electron microscopy. The additions of ceramic nanoparticles suppressed the growth of the intermetallic compound layer Cu6Sn5 at the interface solder/Cu and improved the microstructure of the joints. Furthermore, measurements of mechanical properties showed improved shear strength of Cu/composite solder/Cu joints compared to joints with unreinforced solder. This fact related to all investigated ceramic nanoinclusions and should be attributed to the adsorption of nanoparticles on the grain surface during solidification. However, this effect is less pronounced on increasing the nanoinclusion content from 0.5 wt.% to 1.0 wt.% due to agglomeration of nanoparticles. Moreover, a comparison analysis showed that the most beneficial influence was obtained by minor additions of SiO2 nanoparticles into the SAC305 solder alloy.

  17. A microstructural analysis of solder joints from the electronic assemblies of dismantled nuclear weapons

    Energy Technology Data Exchange (ETDEWEB)

    Vianco, P.T.; Rejent, J.A. [Sandia National Labs., Albuquerque, NM (United States). Materials Joining Dept.

    1997-05-01

    MC1814 Interconnection Boxes from dismantled B57 bombs, and MC2839 firing Sets from retired W70-1 warheads were obtained from the Pantex facility. Printed circuit boards were selected from these components for microstructural analysis of their solder joints. The analysis included a qualitative examination of the solder joints and quantitative assessments of (1) the thickness of the intermetallic compound layer that formed between the solder and circuit board Cu features, and (2) the Pb-rich phase particle distribution within the solder joint microstructure. The MC2839 solder joints had very good workmanship qualities. The intermetallic compound layer stoichiometry was determined to be that of Cu6Sn5. The mean intermetallic compound layer thickness for all solder joints was 0.885 mm. The magnitude of these values did not indicate significant growth over the weapon lifetime. The size distribution of the Pb-rich phase particles for each of the joints were represented by the mean of 9.85 {times} 10{sup {minus}6} mm{sup 2}. Assuming a spherical geometry, the mean particle diameter would be 3.54 mm. The joint-to-joint difference of intermetallic compound layer thickness and Pb-rich particle size distribution was not caused by varying thermal environments, but rather, was a result of natural variations in the joint microstructure that probably existed at the time of manufacture. The microstructural evaluation of the through-hole solder joints form the MC2839 and MC1814 components indicated that the environmental conditions to which these electronic units were exposed in the stockpile, were benign regarding solder joint aging. There was an absence of thermal fatigue damage in MC2839 circuit board, through-hole solder joints. The damage to the eyelet solder joints of the MC1814 more likely represented infant mortality failures at or very near the time of manufacture, resulting from a marginal design status of this type of solder joint design.

  18. SMT无铅生产工艺详解%SMT Production Technology Comments on Lead-free

    Institute of Scientific and Technical Information of China (English)

    顾霭云

    2007-01-01

    1无铅产品PCB设计 到目前为止虽然还没有对无铅PCB设计提出特殊要求,也没有标准,但提倡为环保设计,需要考虑WEEE在选材、制造、使用、回收成本等方面因素的设计思路已经成为大家的共识。对无铅PCB焊盘设计在业界比较一致的有以下一些观点:

  19. Combined thermal, thermodynamic and kinetic modelling for the reliability of high-density lead-free solder interconnections

    OpenAIRE

    Yu, Hao

    2006-01-01

    Continuous miniaturization of electronics devices as well as increasing complexity of soldering metallurgy introduce more and more challenges to the reliability of modern electronics products. Although loading condition plays an important role, the reliability of solder interconnections is ultimately controlled by microstructures' responses to loading. It is therefore of great importance to understand and control the microstructural evolutions of solder interconnections under different loadin...

  20. 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.

  1. 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.

  2. Dural reconstruction by fascia using a temperature-controlled CO2 laser soldering system

    Science.gov (United States)

    Forer, Boaz; Vasilyev, Tamar; Brosh, Tamar; Kariv, Naam; Gil, Ziv; Fliss, Dan M.; Katzir, Abraham

    2005-04-01

    Conventional methods for dura repair are normally based on sutures or stitches. These methods have several disadvantages: (1) The dura is often brittle, and the standard procedures are difficult and time consuming. (2) The seal is leaky. (3) The introduction of a foreign body (e.g. sutures) may cause an inflammatory response. In order to overcome these difficulties we used a temperature controlled fiber optic based CO2 laser soldering system. In a set of in vitro experiments we generated a hole of diameter 10 mm in the dura of a pig corpse, covered the hole with a segment of fascia, and soldered the fascia to the edges of the hole, using 47% bovine albumin as a solder. The soldering was carried out spot by spot, and each spot was heated to 65° C for 3-6 seconds. The soldered dura was removed and the burst pressure of the soldered patch was measured. The average value for microscopic muscular side soldering was 194 mm Hg. This is much higher than the maximal physiological pressure of the CSF fluid in the brain, which is 15 mm Hg. In a set of in vivo experiments, fascia patches were soldered on holes in five farm pigs. The long term results of these experiments were very promising. In conclusion, we have developed an advanced technique for dural reconstruction, which will find important clinical applications.

  3. 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.

  4. 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,...

  5. Development of a solder bump technique for contacting a three-dimensional multi electrode array

    NARCIS (Netherlands)

    Frieswijk, T.A.; Frieswijk, T.A.; Bielen, J.A.; Bielen, J.A.; Rutten, Wim; Bergveld, Piet

    1997-01-01

    The application of a solder bump technique for contacting a three-dimensional multi electrode array is presented. Solder bumping (or C4: Controlled Collapse Chip Connections, also called Flip Chip contacting) is the most suitable contacting technique available for small dimensions and large numbers

  6. Mechanical properties of FeCo magnetic particles-based Sn-Ag-Cu solder composites

    Science.gov (United States)

    Xu, Siyang; Prasitthipayong, Anya; Pickel, Andrea D.; Habib, Ashfaque H.; McHenry, Michael E.

    2013-06-01

    We demonstrate magnetic nanoparticles (MNPs) in enabling lead-free solder reflow in RF fields and improved mechanical properties that impact solder joint reliability. Here, we report on Sn-Ag-Cu (SAC) alloys. SAC solder-FeCo MNP composites with 0, 1, 2, 3, and 4 wt. % FeCo MNP and the use of AC magnetic fields to achieve localized reflow. Electron microscopy of the as-reflowed samples show a decrease in the volume of Sn dendrite regions as well as smaller and more homogeneously dispersed Ag3Sn intermetallic compounds (IMCs) with increasing MNP concentrations. Mechanical properties of the composites were measured by nanoindentation. In pure solder samples and solder composites with 4 wt. % MNP, hardness values increased from 0.18 GPa to 0.20 GPa and the modulus increased from 39.22 GPa to 71.22 GPa. The stress exponent, reflecting creep resistance, increased from 12.85 of pure solder to 16.47 for solder composites with 4 wt. % MNP. Enhanced mechanical properties as compared with the as-prepared solder joints are explained in terms of grain boundary and dispersion strengthening resulting from the microstructural refinement.

  7. Intermetallic compound layer growth kinetics in non-lead bearing solders

    Energy Technology Data Exchange (ETDEWEB)

    Vianco, P.T.; Kilgo, A.C.; Grant, R.

    1995-04-01

    The introduction of alternative, non-lead bearing solders into electronic assemblies requires a thorough investigation of product manufacturability and reliability. Both of these attributes can be impacted by the excessive growth of intermetallic compound (IMC) layers at the solder/substrate interface. An extensive study has documented the stoichiometry and solid state growth kinetics of IMC layers formed between copper and the lead-free solders: 96.5Sn-3.5Ag (wt.%), 95Sn-5Sb, 100Sn, and 58Bi-42Sn. Aging temperatures were 70--205 C for the Sn-based solders and 55--120 C for the Bi-rich solder. Time periods were 1--400 days for all of the alloys. The Sn/Cu, Sn-Ag/Cu, and Sn-Sb/Cu IMC layers exhibited sub-layers of Cu{sub 6}Sn{sub 5} and Cu{sub 3}Sn; the latter composition was present only following prolonged aging times or higher temperatures. The total layer growth exhibited a time exponent of n = 0.5 at low temperatures and a value of n = 0.42 at higher temperatures in each of the solder/Cu systems. Similar growth kinetics were observed with the low temperature 58Bi-42Sn solder; however, a considerably more complex sub-layer structure was observed. The kinetic data will be discussed with respect to predicting IMC layer growth based upon solder composition.

  8. Generation of Tin(II) Oxide Crystals on Lead-Free Solder Joints in Deionized Water

    Science.gov (United States)

    Chang, Hong; Chen, Hongtao; Li, Mingyu; Wang, Ling; Fu, Yonggao

    2009-10-01

    The effect of the anode and cathode on the electrochemical corrosion behavior of lead-free Sn-Ag-Cu and Sn-Ag-Cu-Bi solder joints in deionized water was investigated. Corrosion studies indicate that SnO crystals were generated on the surfaces of all lead-free solder joints. The constituents of the lead-free solder alloys, such as Ag, Cu, and Bi, did not affect the corrosion reaction significantly. In contrast to lead-free solders, PbO x was formed on the surface of the traditional 63Sn-37Pb solder joint in deionized water. A cathode, such as Au or Cu, was necessary for the electrochemical corrosion reaction of solders to occur. The corrosion reaction rate decreased with reduction of the cathode area. The formation mechanism of SnO crystals was essentially a galvanic cell reaction. The anodic reaction of Sn in the lead-free solder joints occurred through solvation by water molecules to form hydrated cations. In the cathodic reaction, oxygen dissolved in the deionized water captures electrons and is deoxidized to hydroxyl at the Au or Cu cathode. By diffusion, the anodic reaction product Sn2+ and the cathodic reaction product OH- meet to form Sn(OH)2, some of which can dehydrate to form more stable SnO· xH2O crystals on the surface of the solder joints. In addition, thermodynamic analysis confirms that the Sn corrosion reaction could occur spontaneously.

  9. Wettability study of lead free solder paste and its effect towards multiple reflow

    Directory of Open Access Journals (Sweden)

    Idris Siti Rabiatull Aisha

    2016-01-01

    Full Text Available Nowadays, wafer bumping using solder paste has come into focus as it provides a low cost method. However, since the industries are moving towards lead-free electronic packaging, a new type of no-clean flux was produced specifically for lead-free solder paste. Therefore, this study is used to evaluate the wettability of two different types of no-clean flux onto copper substrate. Besides, its effect towards multiple reflow was also studied. Reflow soldering was conducted for both types of solder paste that contained different type of no-clean flux for up to double reflow. Two different reflow profile was used. The results showed that the Flux A exhibit better soldering performance after first and second reflow soldering. In addition, type of intermetallic compound (IMC found after first reflow remain the same even after second reflow which was Cu-Sn based. This is shows that Flux A manage to control the diffusion process which will finally leads to a better solder joint performance. Nevertheless, mechanical testing should be carried out in order to evaluate the solder joint strength.

  10. Sterols of Saccharomyces cerevisiae erg6 Knockout Mutant Expressing the Pneumocystis carinii S-Adenosylmethionine:Sterol C-24 Methyltransferase (SAM:SMT)

    Science.gov (United States)

    Kaneshiro, Edna S.; Johnston, Laura Q.; Nkinin, Stephenson W.; Romero, Becky I.; Giner, José-Luis

    2014-01-01

    The AIDS-associated lung pathogen Pneumocystis is classified as a fungus although Pneumocystis has several distinct features such as the absence of ergosterol, the major sterol of most fungi. The P. carinii S-adenosylmethionine:sterol C24-methyltransferase (SAM:SMT) enzyme, coded by the erg6 gene, transfers either one or two methyl groups to the C-24 position of the sterol side chain producing both C28 and C29 24-alkylsterols in approximately the same proportions whereas most fungal SAM:SMT transfer only one methyl group to the side chain. The sterol compositions of wild type Sacchromyces cerevisiae, the erg6 knockout mutant (Δerg6), and Δerg6 expressing the P. carinii or the S. cerevisiae erg6 gene were analyzed by a variety of chromatographic and spectroscopic procedures to examine functional complementation in the yeast expression system. Detailed sterol analyses were obtained using high performance liquid chromatography (HPLC) and proton nuclear magnetic resonance spectroscopy (1H-NMR). The P. carinii SAM:SMT in the Δerg6 restored its ability to produce the C28 sterol ergosterol as the major sterol, and also resulted in low levels of C29 sterols. This indicates that while the P. carinii SAM:SMT in the yeast Δerg6 cells was able to transfer a second methyl group to the side chain, the action of Δ24(28)-sterol reductase (coded by the erg4 gene) in the yeast cells prevented the formation and accumulation of as many C29 sterols as that found in P. carinii. PMID:25230683

  11. The tensile strength characteristics study of the laser welds of biological tissue using the nanocomposite solder

    Science.gov (United States)

    Rimshan, I. B.; Ryabkin, D. I.; Savelyev, M. S.; Zhurbina, N. N.; Pyanov, I. V.; Eganova, E. M.; Pavlov, A. A.; Podgaetsky, V. M.; Ichkitidze, L. P.; Selishchev, S. V.; Gerasimenko, A. Y.

    2016-04-01

    Laser welding device for biological tissue has been developed. The main device parts are the radiation system and adaptive thermal stabilization system of welding area. Adaptive thermal stabilization system provided the relation between the laser radiation intensity and the weld temperature. Using atomic force microscopy the structure of composite which is formed by the radiation of laser solder based on aqua- albuminous dispersion of multi-walled carbon nanotubes was investigated. AFM topograms nanocomposite solder are mainly defined by the presence of pores in the samples. In generally, the surface structure of composite is influenced by the time, laser radiation power and MWCNT concentration. Average size of backbone nanoelements not exceeded 500 nm. Bulk density of nanoelements was in the range 106-108 sm-3. The data of welding temperature maintained during the laser welding process and the corresponding tensile strength values were obtained. Maximum tensile strength of the suture was reached in the range 50-55°C. This temperature and the pointwise laser welding technology (point area ~ 2.5mm) allows avoiding thermal necrosis of healthy section of biological tissue and provided reliable bonding construction of weld join. In despite of the fact that tensile strength values of the samples are in the range of 15% in comparison with unbroken strips of pigskin leather. This situation corresponds to the initial stage of the dissected tissue connection with a view to further increasing of the joint strength of tissues with the recovery of tissue structure; thereby achieved ratio is enough for a medical practice in certain cases.

  12. Optimization of Pb-Free Solder Joint Reliability from a Metallurgical Perspective

    Science.gov (United States)

    Zeng, Kejun; Pierce, Mike; Miyazaki, Hiroshi; Holdford, Becky

    2012-02-01

    To obtain the desired performance of Pb-free packages in mechanical tests, while the solder composition should be carefully selected, the influence of metals dissolved from the soldering pad or under bump metallization (UBM) should also be taken into account. Dissolved metals such as Cu can alter the intermetallic compound (IMC) formation, not only at the local interface but also on the other side of the joint. The high rate of interfacial cracking of Sn-Ag-Cu solder joints on Ni/Au-plated pads is attributed to the high stiffness of the solder and the dual IMC structure of (Cu,Ni)6Sn5 on Ni3Sn4 at the interface. Approaches to avoid this dual IMC structure at the interface are discussed. A rule for selecting the solder alloy composition and the pad surface materials on both sides of the joints is proposed for ball grid array (BGA) packages.

  13. Tensile properties and thermal shock reliability of Sn-Ag-Cu solder joint with indium addition.

    Science.gov (United States)

    Yu, A-Mi; Jang, Jae-Won; Lee, Jong-Hyun; Kim, Jun-Ki; Kim, Mok-Soon

    2012-04-01

    The thermal shock reliability and tensile properties of a newly developed quaternary Sn-1.2Ag-0.5Cu-0.4In (wt%) solder alloy were investigated and compared to those of ternary Sn-Ag-Cu based Pb-free solder alloys. It was revealed that the Sn-1.2Ag-0.5Cu-0.4In solder alloy shows better thermal shock reliability compared to the Sn-1.0Ag-0.5Cu and Sn-3.0Ag-0.5Cu solder alloys. The quaternary alloy has higher strength than Sn-1.0Ag-0.5Cu alloy, and higher elongation than Sn-3.0Ag-0.5Cu alloy. It was also revealed that the addition of indium promotes the formation of Ag3(Sn, In) phase in the solder joint during reflow process.

  14. 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.

  15. 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.)

  16. 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...

  17. Pb-free Sn-Ag-Cu ternary eutectic solder

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, I.E.; Yost, F.G.; Smith, J.F.; Miller, C.M.; Terpstra, R.L.

    1996-06-18

    A Pb-free solder includes a ternary eutectic composition consisting essentially of about 93.6 weight % Sn-about 4.7 weight % Ag-about 1.7 weight % Cu having a eutectic melting temperature of about 217 C and variants of the ternary composition wherein the relative concentrations of Sn, Ag, and Cu deviate from the ternary eutectic composition to provide a controlled melting temperature range (liquid-solid ``mushy`` zone) relative to the eutectic melting temperature (e.g. up to 15 C above the eutectic melting temperature). 5 figs.

  18. The polarity effect of electromigration on intermetallic compound formation and back stress in v-groove solder lines

    Science.gov (United States)

    Ou, Shengquan

    2005-07-01

    The trend of the miniaturization of VLSI and electronic packaging toward higher input/output density, smaller feature size and greater performance makes electromigration a serious reliability concern in flip chip technology. As an integral part of the joint, intermetallic compound (IMC) formation is very important to achieve good joint strength. However, the effect of electromigration on the IMC formation is a subject in which still very little is known. We utilize solder v-groove samples etched on (001) Si wafer with 100 mum opening to study the polarity effect of electromigration on IMC formation in solder joints. We focus on the interaction between chemical and electrical forces, and the influence of interface morphology on the IMC dissolution. The current densities used are from 103 to 104 A/cm2 and the temperature settings are in the range of 120°C to 180°C. We have found in both 95.5Sn3.8Ag0.7Cu/Cu and 96.5Sn3.5Ag systems the growth of the IMC has been enhanced by electric current at the anode and inhibited at the cathode. For Ni-Sn compound, kinetic analysis using the motion of the two interfaces gives the general formula of the growth rate as dXdt=aX + b. We have introduced the concept of mean-field theory and the classic model of Zener's precipitation growth into the discussion of the Cu-Sn compound growth under electromigration. A parabolic dependence of the IMC growth on time at the anode is derived as x 2 ≅ (Cm-Ce)2 (Cs-Ce)2 Dt. The interaction between chemical and electrical forces brings a dynamic equilibrium in IMC dissolution at the cathode. This has been proved theoretically and experimentally. A new critical product has been derived from this dynamic equilibrium, which can provide us a critical IMC thickness before voids formation at a given current density. Our study shows the dissolution rate of Cu with current density 5x103 A/cm2 at 150°C is about 0.076 mum/hr. We also notice that the interface morphology plays an important role in the IMC

  19. Imaging and Analysis of Void-defects in Solder Joints Formed in Reduced Gravity using High-Resolution Computed Tomography

    Science.gov (United States)

    Easton, John W.; Struk, Peter M.; Rotella, Anthony

    2008-01-01

    As a part of efforts to develop an electronics repair capability for long duration space missions, techniques and materials for soldering components on a circuit board in reduced gravity must be developed. This paper presents results from testing solder joint formation in low gravity on a NASA Reduced Gravity Research Aircraft. The results presented include joints formed using eutectic tin-lead solder and one of the following fluxes: (1) a no-clean flux core, (2) a rosin flux core, and (3) a solid solder wire with external liquid no-clean flux. The solder joints are analyzed with a computed tomography (CT) technique which imaged the interior of the entire solder joint. This replaced an earlier technique that required the solder joint to be destructively ground down revealing a single plane which was subsequently analyzed. The CT analysis technique is described and results presented with implications for future testing as well as implications for the overall electronics repair effort discussed.

  20. Electroplated solder alloys for flip chip interconnections

    Science.gov (United States)

    Annala, P.; Kaitila, J.; Salonen, J.

    1997-01-01

    Flip chip mounting of bare dice is gaining widespread use in microelectronics packaging. The main drivers for this technology are high packaging density, improved performance at high frequency, low parasitic effects and potentially high reliability and low cost. Many companies have made significant efforts to develop a technology for bump processing, bare die testing and underfill encapsulation to gain the benefit of all potential advantages. We have focussed on low cost bumping of fully processed silicon wafers to develop a flexible scheme for various reflow requirements. The bumping process is based on galvanic plating from an alloy solution or, alternatively, from several elemental plating baths. Sputtered Mo/Cu or Cr/Cu is used as a wettable base for electroplating. Excess base metal is removed by using the bumps as an etching mask. Variation of the alloy composition or the layer structure, allows the adjustment of the bump reflow temperature for the specific requirements of the assembly. Using binary tin-lead and ternary tin-lead-bismuth alloys, reflow temperatures from 100 °C (bismuth rich alloys) to above 300 °C (lead rich alloys) can be covered. The influence of the plating current density on the final alloy composition has been established by ion beam analysis of the plated layers and a series of reflow experiments. To control the plating uniformity and the alloy composition, a new cup plating system has been built with a random flow pattern and continuous adjustment of the current density. A well-controlled reflow of the bumps has been achieved in hot glycerol up to the eutectic point of tin-lead alloys. For high temperature alloys, high molecular weight organic liquids have been used. A tensile pull strength of 20 g per bump and resistance of 5 mΩ per bump have been measured for typical eutectic tin-lead bumps of 100 μm in diameter.

  1. Laser ablative fluxless soldering (LAFS): 60Sn-40Pb solder wettability tests on laser cleaned OFHC copper substrates

    Energy Technology Data Exchange (ETDEWEB)

    Peebles, H. C.; Keicher, D. M.; Hosking, F. M.; Hlava, P. F.; Creager, N. A.

    1991-01-01

    OFHC copper substrates, cleaned by laser ablation under argon and helium gas, were tested for solder wettability by 60Sn-40Pb using an area-of-spread method. The wettability of copper surfaces cleaned under both argon and helium gas was found to equal or exceed the wettability obtained on this surface in air using a standard RMA flux. The area of spread on copper substrates cleaned under helium was eight times larger than the area of spread of substrates cleaned under argon. The enhanced spreading observed on the substrates cleaned under helium gas was found to be due to surface roughness. 11 refs., 8 figs., 2 tabs.

  2. Detection of micro solder balls using active thermography and probabilistic neural network

    Science.gov (United States)

    He, Zhenzhi; Wei, Li; Shao, Minghui; Lu, Xingning

    2017-03-01

    Micro solder ball/bump has been widely used in electronic packaging. It has been challenging to inspect these structures as the solder balls/bumps are often embedded between the component and substrates, especially in flip-chip packaging. In this paper, a detection method for micro solder ball/bump based on the active thermography and the probabilistic neural network is investigated. A VH680 infrared imager is used to capture the thermal image of the test vehicle, SFA10 packages. The temperature curves are processed using moving average technique to remove the peak noise. And the principal component analysis (PCA) is adopted to reconstruct the thermal images. The missed solder balls can be recognized explicitly in the second principal component image. Probabilistic neural network (PNN) is then established to identify the defective bump intelligently. The hot spots corresponding to the solder balls are segmented from the PCA reconstructed image, and statistic parameters are calculated. To characterize the thermal properties of solder bump quantitatively, three representative features are selected and used as the input vector in PNN clustering. The results show that the actual outputs and the expected outputs are consistent in identification of the missed solder balls, and all the bumps were recognized accurately, which demonstrates the viability of the PNN in effective defect inspection in high-density microelectronic packaging.

  3. Enhanced laser tissue soldering using indocyanine green chromophore and gold nanoshells combination.

    Science.gov (United States)

    Khosroshahi, Mohammad E; Nourbakhsh, Mohammad S

    2011-08-01

    Gold nanoshells (GNs) are new materials that have an optical response dictated by the plasmon resonance. The wavelength at which the resonance occurs depends on the core and shell sizes. The purposes of this study were to use the combination of indocyanine green (ICG) and different concentration of gold nanoshells for skin tissue soldering and also to examine the effect of laser soldering parameters on the properties of repaired skin. Two mixtures of albumin solder and different combinations of ICG and gold nanoshells were prepared. A full thickness incision of 2 × 20 mm(2) was made on the surface and after addition of mixtures it was irradiated by an 810 nm diode laser at different power densities. The changes of tensile strength (σ(t)) due to temperature rise, number of scan (Ns), and scan velocity (Vs) were investigated. The results showed at constant laser power density (I), σ(t) of repaired incisions increases by increasing the concentration of gold nanoshells in solder, Ns, and decreasing Vs. It was demonstrated that laser soldering using combination of ICG + GNs could be practical provided the optothermal properties of the tissue are carefully optimized. Also, the tensile strength of soldered skin is higher than skins that soldered with only ICG or GNs. In our case, this corresponds to σ(t) = 1800 g cm(-2) at I ∼ 47 Wcm(-2), T ∼ 85 [ordinal indicator, masculine]C, Ns = 10, and Vs = 0.3 mms(-1).

  4. A microstructural study of creep and thermal fatigue deformation in 60Sn-40Pb solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Tribula, D.

    1990-06-02

    Thermal fatigue failures of solder joints in electronic devices often arise from cyclic shear strains imposed by the mismatched thermal expansion coefficients of the materials that bind the joint as temperature changes are encountered. Increased solder joint reliability demands a fundamental understanding of the metallurigical mechanisms that control the fatigue to design accurate accelerated probative tests and new, more fatigue resistant solder alloys. The high temperatures and slow strain rates that pertain to thermal fatigue imply that creep is an important deformation mode in the thermal fatigue cycle. In this work, the creep behaviour of a solder joint is studied to determine the solder's microstructural response to this type of deformation and to relate this to the more complex problem of thermal fatigue. It is shown that creep failures arise from the inherent inhomogeneity and instability of the solder microstructure and suggest that small compositional changes of the binary near-eutectic Pn-Sn alloy may defeat the observed failure mechanisms. This work presents creep and thermal fatigue data for several near-eutectic Pb-Sn solder compositions and concludes that a 58Sn-40Pb-2In and a 58Sn-40Pb-2Cd alloy show significantly enhanced fatigue resistance over that of the simple binary material. 80 refs., 33 figs., 1 tab.

  5. Evaluation of Scattered Wave and Stress Concentration Field in a Damaged Solder Joint

    Science.gov (United States)

    Dineva, P.; Gross, D.; Rangelov, T.

    1999-06-01

    Two different, but equally important problems for solder joint reliability are solved. The evaluation of the dynamic stress concentration field in the thin base layer of a damaged solder joint is the first one. It is considered as a rectangular plate with a central macro-crack surrounded with randomly distributed micro-cracks, subjected to uniform time-harmonic tension. The damaged solder joint state is described by the model of Gross and Zhang [1] (International Journal of Solids and Structures29, 1763-1779). The information of the stress concentration field in a damaged solder joint is important to understand the mechanisms in the base components of all electronic packages.The second problem is ultrasonic wave scattering in a solder joint damaged by micro-cracks, considered as a two-dimensional finite multi-layered system. The solution of this problem may aid the creation of the modern non-destructive evaluation method (NDEM) for a high quality control of products in electronic industry.The method of the solution of both boundary-value problems is a direct BIEM (boundary integral equation method). The numerical results obtained for a solder joint with real geometry and physical properties show how the acoustic and stress concentration fields depend on the solder joint damage state. The character of this dependence is discussed.

  6. Wettability Studies of Pb-Free Soldering Materials

    Science.gov (United States)

    Moser, Z.; Gąsior, W.; Pstruś, J.; Dębski, A.

    2008-12-01

    For Pb-free soldering materials, two main substitutes are currently being considered, consisting of Sn-Ag and Sn-Ag-Cu eutectics, both with melting points higher than that of the Sn-Pb eutectic. Therefore, both will require higher soldering temperatures for industrial applications. Also, both eutectics have a higher surface tension than the Sn-Pb eutectic, requiring wettability studies on adding Bi, Sb, and In to the eutectics to decrease the melting points and surface tension. The experimental results for the surface tension were compared with thermodynamic modeling by Butler’s method and were used to create the SURDAT database, which also includes densities for pure metals, binary, ternary, quaternary, and quinary alloys. To model the surface tension, excess Gibbs energies of the molten components were taken from the ADAMIS database. For the case of the Ag-Sn system, enthalpies of formation of Ag3Sn from solution calorimetry were used for checking optimized thermodynamic parameters. In the study of Sn-Ag-Cu-Bi-Sb liquid alloys, the range of possible Bi compositions for practical applications has been used to formulate a generalized metric of wettability, which was checked by measurements of the influence of In on the Sn-Ag-Cu system.

  7. Effect of contact metallization on electromigration reliability of Pb-free solder joints

    Science.gov (United States)

    Ding, Min; Wang, Guotao; Chao, Brook; Ho, Paul S.; Su, Peng; Uehling, Trent

    2006-05-01

    The effect of underbump metallization (UBM) on electromigration (EM) lifetime and failure mechanism has been investigated for Pb-free solder bumps of 97Sn3Ag composition in the temperature range of 110-155 °C. The EM lifetime of the SnAg Pb-free solders with either Cu or Ni UBM was found to be better than the eutectic SnPb (63Sn37Pb) solders but worse than high-Pb (95Pb5Sn) solders. In the test temperature range, the EM lifetimes were found to be comparable for Cu and Ni UBMs but with different activation energies: 0.64-0.72 eV for Cu UBM and 1.03-1.11 eV for Ni UBM. EM failure was observed only in solder bumps with electron current flow from UBM to the substrate. Failure analysis revealed that EM damage was initiated by the formation of intermetallic compounds (IMC) at the UBM/solder interface which was found to be significantly enhanced by mass transport driven by the electron current. Under EM, the continued growth of IMC with the dissolution of the UBM and the accumulation of Kirkendall voids resulted in the formation of interfacial cracks and eventual EM failure of the solder bump. For Ni UBM, the IMC formation was dominated by the Ni3Sn4 phase while for Cu UBM, a bilayer of Cu3Sn/Cu6Sn5 was found. Void formation at the Cu6Sn5/solder interface was found to be important in controlling the EM lifetime of the Cu UBM solder.

  8. 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.

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

    Science.gov (United States)

    Zhou, Xiuyun; Zhou, Jinlong; Tian, Guiyun; Wang, Yizhe

    2015-01-01

    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. PMID:26473871

  10. Life Prediction of Ball Grid Array Soldered Joints under Thermal Cycling Loading by Fracture Mechanics Method

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Fatigue crack propagation life of ball grid array (BGA) soldered joints during thermal cycling loading was investigated by fracture mechanics approach using finite element analysis. The relationships between the strain energy release rate (G) and crack size (α), thermal cycle numbers (N) can be derived. Based on the relationships, fatigue life of the soldered joints was determined. The results showed that crack propagation life was higher than crack initiation life. Therefore, it appears that it is more appropriate to predict the fatigue life of soldered joints using the fracture mechanics method.

  11. Research on defects inspection of solder balls based on eddy current pulsed thermography.

    Science.gov (United States)

    Zhou, Xiuyun; Zhou, Jinlong; Tian, Guiyun; Wang, Yizhe

    2015-10-13

    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.

  12. 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.

  13. Effect of constraint on crack propagation behavior in BGA soldered joints

    Institute of Scientific and Technical Information of China (English)

    王莉; 王国忠; 方洪渊; 钱乙余

    2001-01-01

    The effects of stress triaxiality on crack propagation behavior in the BGA soldered joint were analyzed using FEM method. The computation results verified that stress triaxiality factor has an important effect on crack growth behavior. Crack growth rate increased with increasing stress triaxiality at the near-tip region, which is caused by increasing crack lengths or decreasing solder joint heights. Solder joint deformation is subjected to constraint effect provided by its surrounding rigid ceramic substrate, the constraint can be scaled by stress triaxiality near crack tip region. Therefore, it can be concluded that crack growth rate increased when the constraint effect increases.

  14. Observations of microstructural coarsening in micro flip-chip solder joints

    Science.gov (United States)

    Barney, Monica M.; Morris, J. W.

    2001-09-01

    Coarsening of solder microstructures dramatically affects fatigue lifetimes. This paper presents a study of microstructural evolution due to thermal cycling and aging of small solder joints. The lead-tin solder joints in this study have a height of 55 5 m and a tin content of 65 70 wt.%, with a degenerate eutectic microstructure. The joint microstructure coarsens more rapidly during aging at 160°C than cycling from 0 160°C. No coarsened bands are observed. The cycling data scales with standard coarsening equations, while the aging data fits to an enhanced trend. The joints experiencing 2.8% strain during cycling fail by 1000 cycles.

  15. 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.

  16. A cause of the non-solderability of ceramic capacitor terminations

    Science.gov (United States)

    Cozzolino, M. J.; Kumar, A.; Ewell, G. J.

    1981-01-01

    The results of an analysis into the cause of the non-solderability of multiple defective part lots from two capacitor manufacturers are described. This analysis consisted of visual, scanning electron microscopic, surface, and metalographic examinations and analyses. The results indicated that non-solderability results from areas of excess porosity in the termination which are caused by segregation of ink constituents during manufacturing. This segregation can be minimized by proper monitoring and control of process variables; where excess porosity does occur, solderability can be improved by proper precleaning of parts.

  17. Wettability study of lead free solder paste and its effect towards multiple reflow

    OpenAIRE

    Idris Siti Rabiatull Aisha; Zuleikha Siti; Abd Malek Zetty Akhtar

    2016-01-01

    Nowadays, wafer bumping using solder paste has come into focus as it provides a low cost method. However, since the industries are moving towards lead-free electronic packaging, a new type of no-clean flux was produced specifically for lead-free solder paste. Therefore, this study is used to evaluate the wettability of two different types of no-clean flux onto copper substrate. Besides, its effect towards multiple reflow was also studied. Reflow soldering was conducted for both types of solde...

  18. Surgery today: from soldering iron to computer%外科今日:从烙铁到计算机

    Institute of Scientific and Technical Information of China (English)

    黄志强

    2012-01-01

    The reform of medical concepts,development of medical knowledge and innovation of medical techniques bring surgeons from the era of soldering iron to the digital era.In the 21st century,the demand for an excellent surgeon goes beyond by adding minimal invasiveness and optinal recovery of patients.With modern technology,we could obtain the information of external presentations as well as the internal relationship of organs by three dimensional reconstructions.With virtual technologies and robotic surgical systems,preoperative surgery planning and remote control of surgery could be realized currently.These changes are not only the reformation of minimally invasive surgcry,but also the trends of development of surgery in the 21st century.

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

    CERN Document Server

    Koo, Ja-Myeong

    2007-01-01

    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 (hereafter OSP). During bonding, continuous AuIn2, Ni3(Sn,In)4 and Cu6(Sn,In)5 intermetallic compound (IMC) layers were formed at the solder/E-NG, solder/ENIG and solder/OSP interface, respectively. The interfacial reactions between the solder and I-Ag substrate during bonding resulted in the formation of Cu6(Sn,In)5 and Cu(Sn,In)2 IMCs with a minor Ag element. The In-48Sn/I-Ag solder joint showed the best shear properties among the four solder joints after bonding, whereas the solder/ENIG solder joint exhibited the weakest mechanical integrity.

  20. Electromigration Reliability and Morphologies of Cu Pillar Flip-Chip Solder Joints with Cu Substrate Pad Metallization

    Science.gov (United States)

    Lai, Yi-Shao; Chiu, Ying-Ta; Chen, Jiunn

    2008-10-01

    The Cu pillar is a thick underbump metallurgy (UBM) structure developed to alleviate current crowding in a flip-chip solder joint under operating conditions. We present in this work an examination of the electromigration reliability and morphologies of Cu pillar flip-chip solder joints formed by joining Ti/Cu/Ni UBM with largely elongated ˜62 μm Cu onto Cu substrate pad metallization using the Sn-3Ag-0.5Cu solder alloy. Three test conditions that controlled average current densities in solder joints and ambient temperatures were considered: 10 kA/cm2 at 150°C, 10 kA/cm2 at 160°C, and 15 kA/cm2 at 125°C. Electromigration reliability of this particular solder joint turns out to be greatly enhanced compared to a conventional solder joint with a thin-film-stack UBM. Cross-sectional examinations of solder joints upon failure indicate that cracks formed in (Cu,Ni)6Sn5 or Cu6Sn5 intermetallic compounds (IMCs) near the cathode side of the solder joint. Moreover, the ~52- μm-thick Sn-Ag-Cu solder after long-term current stressing has turned into a combination of ~80% Cu-Ni-Sn IMC and ~20% Sn-rich phases, which appeared in the form of large aggregates that in general were distributed on the cathode side of the solder joint.

  1. Report on an Assessment of the Application of EPP Results from the Strain Limit Evaluation Procedure to the Prediction of Cyclic Life Based on the SMT Methodology

    Energy Technology Data Exchange (ETDEWEB)

    Jetter, R. I. [R. I. Jetter Consulting, Pebble Beach, CA (United States); Messner, M. C. [Argonne National Lab. (ANL), Argonne, IL (United States); Sham, T. -L. [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, Y. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    The goal of the proposed integrated Elastic Perfectly-Plastic (EPP) and Simplified Model Test (SMT) methodology is to incorporate an SMT data based approach for creep-fatigue damage evaluation into the EPP methodology to avoid the separate evaluation of creep and fatigue damage and eliminate the requirement for stress classification in current methods; thus greatly simplifying evaluation of elevated temperature cyclic service. This methodology should minimize over-conservatism while properly accounting for localized defects and stress risers. To support the implementation of the proposed methodology and to verify the applicability of the code rules, analytical studies and evaluation of thermomechanical test results continued in FY17. This report presents the results of those studies. An EPP strain limits methodology assessment was based on recent two-bar thermal ratcheting test results on 316H stainless steel in the temperature range of 405 to 7050C. Strain range predictions from the EPP evaluation of the two-bar tests were also evaluated and compared with the experimental results. The role of sustained primary loading on cyclic life was assessed using the results of pressurized SMT data from tests on Alloy 617 at 9500C. A viscoplastic material model was used in an analytic simulation of two-bar tests to compare with EPP strain limits assessments using isochronous stress strain curves that are consistent with the viscoplastic material model. A finite element model of a prior 304H stainless steel Oak Ridge National Laboratory (ORNL) nozzle-to-sphere test was developed and used for an EPP strain limits and creep-fatigue code case damage evaluations. A theoretical treatment of a recurring issue with convergence criteria for plastic shakedown illustrated the role of computer machine precision in EPP calculations.

  2. Abnormal growth of Ag3Sn intermetallic compounds in Sn-Ag lead-free solder

    Institute of Scientific and Technical Information of China (English)

    SHEN Jun; LIU Yongchang; GAO Houxiu

    2006-01-01

    The abnormal growth of Ag3Sn intermetallic compounds in eutectic Sn-3.5% Ag solder was investigated through high-temperature aging treatment. Microstructural evolutions of this solder before and after the aging treatment were observed by optical microscopy and scanning electron microscopy. Precise differential thermal analysis was made to study the changes in enthalpies of the solder under different conditions. The results reveal that the water-cooled solder is in metastable thermodynamic state due to the high free energy of Ag3Sn nanoparticles, which sporadically distribute in the matrix as second-phase. The second-phase Ag3Sn nanoparticles aggregate rapidly and grow to form bulk intermetallic compounds due to the migration of grain boundary between primary Sn-rich phase and the Ag3Sn nanoparticles during high temperature aging treatment.

  3. 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

    Soldering of cast alloys to the dies has been a continuing source of die surface damage in the aluminum die-casting industry. To reduce the repair and maintenance costs, an approach to modeling the damage and predicting the die lifetime is required. The aim of the present study is the estimation...... 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...

  4. Climate specific thermomechanical fatigue of flat plate photovoltaic module solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Bosco, Nick; Silverman, Timothy J.; Kurtz, Sarah

    2016-07-01

    FEM simulations of PbSn solder fatigue damage are used to evaluate seven cities that represent a variety of climatic zones. It is shown that the rate of solder fatigue damage is not ranked with the cities' climate designations. For an accurate ranking, the mean maximum daily temperature, daily temperature change and a characteristic of clouding events are all required. A physics-based empirical equation is presented that accurately calculates solder fatigue damage according to these three factors. An FEM comparison of solder damage accumulated through service and thermal cycling demonstrates the number of cycles required for an equivalent exposure. For an equivalent 25-year exposure, the number of thermal cycles (-40 degrees C to 85 degrees C) required ranged from roughly 100 to 630 for the cities examined. It is demonstrated that increasing the maximum cycle temperature may significantly reduce the number of thermal cycles required for an equivalent exposure.

  5. Thermal analysis of selected tin-based lead-free solder alloys

    DEFF Research Database (Denmark)

    Palcut, Marián; Sopoušek, J.; Trnková, L.

    2009-01-01

    The Sn-Ag-Cu alloys have favourable solderability and wetting properties and are, therefore, being considered as potential lead-free solder materials. In the present study, tin-based Sn-Ag-Cu and Sn-Ag-Cu-Bi alloys were studied in detail by a differential scanning calorimetry (DSC) and thermodyna......The Sn-Ag-Cu alloys have favourable solderability and wetting properties and are, therefore, being considered as potential lead-free solder materials. In the present study, tin-based Sn-Ag-Cu and Sn-Ag-Cu-Bi alloys were studied in detail by a differential scanning calorimetry (DSC...... was simulated using the Thermo-Calc software package. This approach enabled us to obtain the enthalpy of cooling for each alloy and to compare its temperature derivative with the experimental DSC curves....

  6. Shear Deformation Behaviors of Sn3.5Ag Lead-free Solder Samples

    Institute of Scientific and Technical Information of China (English)

    Jing Han; Hongtao Chen; Mingyu Li; Chunqing Wang

    2013-01-01

    In this study,shear tests have been performed on the as-reflowed Sn3.5Ag solder bumps and joints to investigate the deformation behavior of Sn3.5Ag lead-free solder samples.Scanning electron microscopy (SEM) was employed to characterize the microstructures of the samples and orientation imaging microscopy (OIM) with electron backscattered diffraction (EBSD) in SEM was used to obtain crystallographic orientation of grains to provide a detailed characterization of the deformation behavior in Sn3.5Ag solder samples after shear tests.The deformation behavior in solder samples under shear stress was discussed.The experimental results suggest that the dynamic recrystallization could occur under shear stress at room temperature and recrystallized grains should evolve from subgrains by rotation.Compared with that of non-recrystallized and as-reflowed microstructures,the microhardness of the recrystallized microstructure decreased after shear tests.

  7. Joint Strength with Soldering of Al2O3 Ceramics After Ni-P Chemical Plating

    Institute of Scientific and Technical Information of China (English)

    邹贵生; 吴爱萍; 张德库; 孟繁明; 白海林; 张永清; 黎义; 巫世杰; 顾兆旃

    2004-01-01

    Ni-P alloy was chemically plated on Al2O3 ceramics to produce uniform alloy coatings at temperatures below 70℃. Cu metal was electroplated onto the Ni-P coating to facilitate the soldering and shorten the chemical plating time. Then, the electroplated ceramic specimens were soldered with 60 wt.% Sn-40 wt.% Pb solder in active colophony. The highest shear strength was acquired after the heat treatment at 170℃ for 15 min. The joint fractures mostly propagated along the interface between the ceramics and the Ni-P coating, with some fracture in both the ceramics and the Ni-P coating near the interface and some along the interface between the Cu and Ni-P coatings. The results show that ceramic surface roughness and the chemical plating parameters influence the coating quality, and that suitable heat treatment before the soldering also improves the adhesion between the ceramics and Ni-P coatings, thus strengthening the joints.

  8. Correlation Between Sn Grain Orientation and Corrosion in Sn-Ag-Cu Solder Interconnects

    Science.gov (United States)

    Lee, Tae-Kyu; Liu, Bo; Zhou, Bite; Bieler, Thomas; Liu, Kuo-Chuan

    2011-09-01

    The impact of a marine environment on Sn-Ag-Cu interconnect reliability is examined using salt spray exposure followed by thermal cycling. Sn-Ag-Cu solder alloy wafer-level packages, with and without pretreatment with 5% NaCl salt spray, were thermally cycled to failure. The prior salt spray reduced the characteristic lifetime of the Sn-Ag-Cu solder joints by over 43%. Although Sn-based materials show strong resistance to corrosion, the nature of localized corroded areas at critical locations in the solder joint caused significant degradation in the Sn-Ag-Cu solder joints. An important link between the corrosion path and Sn grain orientation was observed using orientation imaging microscopy (OIM). A strong correlation between the corrosion path and grain orientation was identified, indicating that the corrosion attack preferentially followed the basal plane of the Sn lattice.

  9. Influence of Asymmetrical Waveform on Low-Cycle Fatigue Life of Micro Solder Joint

    Science.gov (United States)

    Kanda, Yoshihiko; Kariya, Yoshiharu

    2010-02-01

    The effects of waveform symmetry on the low-cycle fatigue life of the Sn-3.0Ag-0.5Cu alloy have been investigated, using micro solder joint specimens with approximately the same volume of solder as is used in actual products. Focusing on crack initiation life, fatigue tests on Sn-Ag-Cu micro solder joints using asymmetrical triangular waveforms revealed no significant reduction in fatigue life. A slight reduction in fatigue life at low strain ranges caused by an increase in the fatigue ductility exponent, which is the result of a weakening microstructure due to loads applied at high temperature for long testing time, was observed. This was due to the fact that grain boundary damage, which has been reported in large-size specimens subjected to asymmetrical triangular waveforms, does not occur in Sn-Ag-Cu micro size solder joints with only a small number of crystal grain boundaries.

  10. 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.

  11. Evaluation of Detachable Ga-Based Solder Contacts for Thermoelectric Materials

    Science.gov (United States)

    Kolb, H.; Sottong, R.; Dasgupta, T.; Mueller, E.; de Boor, J.

    2017-08-01

    Low electrical and thermal contact resistances are a prerequisite for highly efficient thermoelectric generators. Likewise, certain measurement setups for characterization of thermoelectric materials rely on good-quality contacts between sample and setup. Detachable contacts are an interesting alternative to permanent contacting solutions due to ease of handling and nondestructive disassembly of valuable samples. Therefore, the applicability of gallium-based liquid metal solder as detachable contact material was studied, particularly with regard to compatibility of the solder with state-of-the-art thermoelectric materials CoSb3, Mg2Si, and FeSi2. Tungsten, nickel, chromium, and titanium were tested as protective coatings between the thermoelectric material and liquid metal solder. Electrical measurements showed that some materials form excellent and stable contacts with the solder for a limited temperature range. At higher temperatures, application of a protective layer was found to be necessary for all investigated materials. Tungsten and nickel showed promising results as protective layer.

  12. Nano ZrO2 Particulate-reinforced Lead-Free Solder Composite

    Institute of Scientific and Technical Information of China (English)

    Jun SHEN; Yongchang LIU; Dongjiang WANG; Houxiu GAO

    2006-01-01

    A lead-free solder composite was prepared by adding ZrO2 nanopowders in eutectic Sn-Ag alloy. Microstructural features and microhardness properties of those solders with different ZrO2 nanopowder fraction were examined. Results indicate that the addition of ZrO2 nanopowders reduced the size ofβ-Sn grains and restrained the formation of bulk Ag3Sn intermetallic compounds (IMCs) due to the adsorption effect of the ZrO2 particles. The Vicker's hardness of the obtained lead-free solder composites fits well with the Hall-Petch relationship. The refinement of β-Sn grains favors to improve the microhardness of composite solders.

  13. Microstructurally based thermomechanical fatigue lifetime model of solder joints for electronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Frear, D.R.; Rashid, M.M.; Burchett, S.N.

    1993-07-01

    We present a new methodology for predicting the fatigue life of solder joints for electronics applications. This approach involves integration of experimental and computational techniques. The first stage involves correlating the manufacturing and processing parameters with the starting microstructure of the solder joint. The second stage involves a series of experiments that characterize the evolution of the microstructure during thermal cycling. The third stage consists of a computer modeling and simulation effort that utilizes the starting microstructure and experimental data to produce a reliability prediction of the solder joint. This approach is an improvement over current methodologies because it incorporates the microstructure and properties of the solder directly into the model and allows these properties to evolve as the microstructure changes during fatigue.

  14. Interfacial Reactions and Joint Strengths of Sn- xZn Solders with Immersion Ag UBM

    Science.gov (United States)

    Jee, Y. K.; Yu, Jin

    2010-10-01

    The solder joint microstructures of immersion Ag with Sn- xZn ( x = 0 wt.%, 1 wt.%, 5 wt.%, and 9 wt.%) solders were analyzed and correlated with their drop impact reliability. Addition of 1 wt.% Zn to Sn did not change the interface microstructure and was only marginally effective. In comparison, the addition of 5 wt.% or 9 wt.% Zn formed layers of AgZn3/Ag5Zn8 at the solder joint interface, which increased drop reliability significantly. Under extensive aging, Ag-Zn intermetallic compounds (IMCs) transformed into Cu5Zn8 and Ag3Sn, and the drop impact resistance at the solder joints deteriorated up to a point. The beneficial role of Zn on immersion Ag pads was ascribed to the formation of Ag-Zn IMC layers, which were fairly resistant to the drop impact, and to the suppression of the brittle Cu6Sn5 phase at the joint interface.

  15. 微电子表面贴装关键技术与装备%The Key Technique and Equipment of Micro-electronic Device SMT

    Institute of Scientific and Technical Information of China (English)

    张雍蓉; 刘昊

    2013-01-01

      In this paper,authors put forw ard that optional drag soldering process and dip soldering process can be finished w ithout special m old. A uthors affirm that by using m old shielded w ave soldering technique the m anufacture double-sided packaging forPC B can be achieved.The production efficiency w ill be significantly im proved and the preparing tim e for stick-up solder glue w ill be shortened.B y reducing production costs itw illm ake com patibility w ith traditionalw ave soldering.It can also be conclude that thru-hole reflow soldering process is benefit for im proving w elding quality and low ering process.A uthor m ake research on the direction of SM T printequipm entw hich tow ards dualtransferboard.The SM T equipm entbecom es faster,high-precision,m ore functions,intelligent, m ore cantilevers,m ore placem entheads and flexible connection.A nd the reflow device is on the w ay to m ulti-channelflow controlling,localforced cooling and tem perature m onitoring forcom ponents%  提出了选择性拖焊工艺,浸焊工艺,在无需制作专门的模具即可完成。确认了采用屏蔽模具波峰焊接工艺,实现双面混装PC B 波峰焊生产,大幅度提高双面混装PC B 生产效率,减少粘贴阻焊胶的准备时间,降低生产成本,达到与传统波峰焊接兼容以及通孔回流焊接工艺,对提升焊接质量、减少工艺流程的优势。研究了SM T 印刷设备的双路输送板发展方向、贴片设备的高速、高精密、多功能、智能化、多悬臂、多贴装头、柔性连接模块化发展方向、以及再流焊设备的多喷嘴气流控制、局部强制冷却、可监测元器件温度的发展方向。

  16. C4NP - Lead Free Flip Chip Solder Bumping Manufacturing and Reliability Data%C4NP-无铅倒装晶片焊凸形成生产工艺与可靠性数据

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    受控倒塌芯片连接新工艺是一种由IBM公司开发、由Suss MicroTec公司推向商品化的新型焊凸形成技术.受控倒塌芯片连接新工艺采用各种无铅焊料合金致力于解决现有的凸台.形成技术限定,使低成本小节距焊凸形成成为可能.受控倒塌芯片连接新工艺是一种焊球转移技术,熔焊料被注入预先制成并可重复使用的玻璃模板(模具).这种注满焊料的模具在焊料转入圆片之前先经过检查以确保高成品率.注满焊料的模具与圆片达到精确的接近后以与液态熔剂复杂性无关的简单工序转移在整个300 mm(或300 mm以下)圆片上.受控倒塌芯片连接新工艺技术能够在焊膏印刷中实现小节距凸台形成的同时提供相同合金选择的适应性.这种简单的受控倒塌芯片连接新工艺使低成本、高成品率以及快速封装周期的解决方法对于细节距FCiP以及WLCSP凸台形成均能适用.%C4NP is a new solder bumping technology developed by IBM and commercialized by Suss MicroTec. C4NP addresses the limitations of existing bumping technologies by enabling low-cost, fine pitch bumping using a variety of lead-free solder alloys. C4NP is a solder transfer technology where molten solder is injected into pre-fabricated and reusable glass templates (molds). The filled mold is inspected prior to solder transfer to the wafer to ensure high final yields. Filled mold and wafer are brought into close proximity and solder bumps are transferred onto the entire 300 mm (or smaller)wafer in a single process step without the complexities associated with liquid flux. C4NP technology is capable of fine pitch bumping while offering the same alloy selection flexibility as solder paste printing.The simplicity of the C4NP process makes it a low cost, high yield and fast cycle time solution for both,fine-pitch FCiP as well as WLCSP bumping applications.This paper summarizes the latest manufacturing and reliability data for

  17. Studies of intermetallic growth in Cu-solder systems and wettability at solid-liquid interfaces

    OpenAIRE

    Martin, Raymond W.

    1991-01-01

    Approved for public release; distribution is unlimited The metallurgical bond formed between tin-lead solder and the copper substrate is characterized by the formation of an intermetallic compound layer. The growth of the intermetallic layer is the result of competing mechanisms, growth of the intermetallic at the intermetallic/copper interface and its dissolution at the intermetallic/liquid solder interface. These were studied by determining the dissolution rates of the copper and the i...

  18. Joint Lead-Free Solder Test Program for High Reliability Military and Space Applications

    Science.gov (United States)

    Brown, Christina

    2004-01-01

    Current and future space and defense systems face potential risks from the continued use of tin-lead solder, including: compliance with current environmental regulations, concerns about potential environmental legislation banning lead-containing products, reduced mission readiness, and component obsolescence with lead surface finishes. For example, the United States Environmental Protection Agency (USEPA) has lowered the Toxic Chemical Release reporting threshold for lead to 100 pounds. Overseas, the Waste Electrical and Electronic Equipment (WEEE) and the Restriction on Hazardous Substances (RoHS) Dicctives in Europe and similar mandates in Japan have instilled concern that a legislative body will prohibit the use of lead in aerospace/military electronics soldering. Any potential banning of lead compounds could reduce the supplier base and adversely affect the readiness of missions led by the National Aeronautics and Space Administration (NASA) and the U.S. Department of Defense (DoD). Before considering lead-free electronics for system upgrades or future designs, however, it is important for the DoD and NASA to know whether lead-free solders can meet their systems' requirements. No single lead-free solder is likely to qualify for all defense and space applications. Therefore, it is important to validate alternative solders for discrete applications. As a result of the need for comprehensive test data on the reliability of lead-free solders, a partnership was formed between the DoD, NASA, and several original equipment manufactures (OEMs) to conduct solder-joint reliability (laboratory) testing of three lead-free solder alloys on newly manufactured and reworked circuit cards to generate performance data for high-reliability (IPC Class 3) applications.

  19. Thermomechanical cycling investigation of CU particulate and NITI reinforced lead-free solder

    OpenAIRE

    Horton, W. Scott.

    2006-01-01

    In todayâ s Flip Chip (FC) and Ball Grid Array (BGA) electronic packages solder joints provide both the electrical as well as the mechanical connections between the silicon chip and the substrate. Due to coefficient of thermal expansion (CTE) differences between the chip and substrate the solder joints undergo thermomechanical stresses and strains as an electronic package is heated and cooled with power on/off cycles. Advances in chip designs result in chips that are larger, run hotter and d...

  20. 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.

  1. Modeling of thermal processes in waveguide tracts induction soldering

    Science.gov (United States)

    Murygin, A. V.; Tynchenko, V. S.; Laptenok, V. D.; Emilova, O. A.; Seregin, Yu N.

    2017-02-01

    The problem solving of the induction heating models development, which describe the heating of the separate structural assembly components of the waveguide path and product generally, is presented in this paper. Proposed mathematical models are based on the thermodynamics equation and on the heat balance law. The system of the heating process mathematical models, such as surge tube and flange heating, and the mathematical model of the energy distribution are presented. During the modeling process with Matlab system by using mathematical models graphs of the tube, flange and coupling heating were obtained. These design charts are confirmed by the results of the experimental study. During the experimental studies pyrometers for temperature control and a video camera for visual control of the process parameters were used. On the basis of obtained models the induction soldering process features analysis is carried out and the need of its automation by the using of the information control systems for thermal management between the connection elements is revealed.

  2. 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.

  3. 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.

  4. Soldering in a Reduced Gravity Environment (SoRGE)

    Science.gov (United States)

    Easton, John W.; Struk, Peter M.

    2012-01-01

    Future long-duration human exploration missions will be challenged by constraints on mass and volume allocations available for spare parts. Addressing this challenge will be critical to the success of these missions. As a result, it is necessary to consider new approaches to spacecraft maintenance and repair that reduce the need for large replacement components. Currently, crew members on the International Space Station (ISS) recover from faults by removing and replacing, using backup systems, or living without the function of Orbital Replacement Units (ORUs). These ORUs are returned to a depot where the root cause of the failure is determined and the ORU is repaired. The crew has some limited repair capability with the Modulation/DeModulation (MDM) ORU, where circuit cards are removed and replace in faulty units. The next step to reducing the size of the items being replaced would be to implement component-level repair. This mode of repair has been implemented by the U.S. Navy in an operational environment and is now part of their standard approach for maintenance. It is appropriate to consider whether this approach can be adapted for future spaceflight operations. To this end, the Soldering in a Reduced Gravity Environment (SoRGE) experiment studied the effect of gravity on the formation of solder joints on electronic circuit boards. This document describes the SoRGE experiment, the analysis methods, and results to date. This document will also contain comments from the crew regarding their experience conducting the SoRGE experiment as well as recommendations for future improvements. Finally, this document will discuss the plans for the SoRGE samples which remain on ISS.

  5. Solder-Filling of a Cicc Cable for the Efda Dipole Magnet

    Science.gov (United States)

    Bauer, P.; Bruzzone, P.; Cau, F.; Weiss, K.; Portone, A.; Salpietro, E.; Vogel, M.; Vostner, A.

    2008-03-01

    Several prototype Cable-In-Conduit-Conductors (CICC) for the superconducting EDIPO (Efda DIPOle) revealed a degradation of their critical current (Ic) increasing with each loading cycle. The strong Lorentz-forces during operation in combination with the limited support of the single strands against these forces are thought to be the cause of the permanent degradation of the brittle Nb3Sn superconductor from which the multi-stranded CICC are made. In summer 2006 EFDA started to explore the possibility to remedy the Ic degradation by solder-filling the conductor in order to mechanically stabilize the twisted-strand cable inside the conduit. This solution was not considered as the main one, but as an emergency solution to be applied to the completed magnet, should every other option fail. The solder-filling approach was previously applied with success in some cases. Some issues, however, needed to be clarified before this solution could be proposed for the EDIPO project. The most important among them are the choice of solder material, details of the solder filling process, and the thermo-mechanical implications of a solder-filled, high-field, high-current cable. This work, being reported here, made use not only of simulation but also of experiments, such as the mechanical testing of solder filled cables at cryogenic temperatures.

  6. Preliminary Study on Synthesis of Organolead Halide with Lead Derived from Solder Wire

    Science.gov (United States)

    Pratiwi, P.; Rahmi, G. N.; Aimon, A. H.; Iskandar, F.; Abdullah, M.; Nuryadin, B. W.

    2016-08-01

    Organolead halide has attracted great attention for application in perovskite solar cells due to its high power conversion efficiency (PCE) of up to 20.1%. One of the most common perovskite materials is lead based reagent. In this research, we have synthesized organolead halide with lead extracted from solder wire. In the preparation procedure, first PbCl2 and PbI2 are produced by reacting lead from the solder wire with NaCl and KI, which are used as the basic substance for the perovskite material. Then, in order to get perovskite solution, the powders are reacted with methylamine iodide (MAI) in dimethylformamide (DMF) using a solution based method. Further, the spin coating method is used to fabricate perovskite thin film. The XRD peak results agreed with JCPDS Powder Diffraction of PbCl2 and PbI2. Based on FTIR, the transmittance spectra of the organolead mixed halide that was prepared using solder wire lead exhibited absorption peaks identical to organolead mixed halide using commercial lead. The UV-Vis absorbance spectra of the organolead mixed halide from solder wire lead also exhibited the same absorption ability as from commercial lead. Morever, EDS measurement showed that the element composition of the perovskite thin film using lead from solder wire identical to that from commercial lead. This indicates that solder wire lead is suitable enough for organolead halide material synthesis.

  7. Effect of Cu concentration on morphology of Sn-Ag-Cu solders by mechanical alloying

    Science.gov (United States)

    Kao, Szu-Tsung; Duh, Jenq-Gong

    2004-12-01

    The mechanical alloying (MA) process is considered an alternative approach to produce solder materials. In this study, the effect of Cu concentration in the ternary Sn-3.5Ag-xCu (x=0.2, 0.7, and 1) solder by MA was investigated. The (Cu,Sn) solid solution was precipitated as the Cu6Sn5 intermetallic compound (IMC), which was distributed nonuniformly through the microstructure. The Cu6Sn5 IMC, which was present in the SnAgCu solder with high Cu composition, causes the as-milled MA particle to fracture to a smaller size. Appreciable distinction on morphology of as-milled MA powders with different Cu content was revealed. When the Cu concentration was low (x=0.2), MA particle aggregated to a spherical ingot with large particle size. For higher Cu concentration (x=0.7 and x=1), the MA particle turned to flakes with smaller particle size. The distinction of the milling mechanism of Sn-3.5Ag-xCu (x=0.2, 0.7, and 1) solder by the MA process was discussed. An effective approach was developed to reduce the particle size of the SnAgCu solder from 1 mm down to 10-100 µm by doping the Cu6Sn5 nanoparticle during the MA process. In addition, the differential scanning calorimetry (DSC) results also ensure the compatibility to apply the solder material for the reflow process.

  8. Development of high strength Sn-Mg solder alloys with reasonable ductility

    Science.gov (United States)

    Alam, Md Ershadul; Gupta, Manoj

    2013-09-01

    This study discussed the development of a series of new lead-free Sn-Mg solders by incorporating varying amounts of Mg (0.8, 1.5 and 2.5 wt. %) into pure Sn using disintegrated melt deposition technique followed by room temperature extrusion. All extruded Sn and Sn-Mg solder samples were characterized. Microstructural characterization studies revealed equiaxed grain morphology, minimal porosity and relatively uniform distribution of secondary phase. Better coefficient of thermal expansion was observed for Sn-2.5Mg sample when compared to conventional Sn-37Pb solder. Melting temperature of Sn-1.5Mg was found to be 212°C which is much lower than the conventional Sn-Ag-Cu or Sn-Cu (227°C) solders. Microhardness was increased with increasing amount of Mg in pure Sn. Room temperature tensile test results revealed that newly developed Sn-Mg solders exhibit enhanced strengths (0.2% yield strength and ultimate tensile strength) with comparable (if not better) ductility when compared to other commercially available and widely used Sn-based solder alloys.

  9. Effect of interface microstructure on the mechanical properties of Pb-free hybrid microcircuit solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, C.L.; Vianco, P.T.; Rejent, J.A.

    1998-08-01

    Although Sn-Pb eutectic alloy is widely used as a joining material in the electronics industry, it has well documented environmental and toxicity issues. Sandia National Laboratories is developing alternative solder materials to replace traditional Pb-containing alloys. The alloys are based on the Sn-Ag, Sn-Ag-Bi and Sn-Ag-Bi-Au systems. Prototype hybrid microcircuit (HMC) test vehicles have been developed to evaluate these Pb-free solders, using Au-Pt-Pd thick film metallization. Populated test vehicles with surface mount devices have been designed and fabricated to evaluate the reliability of surface mount solder joints. The test components consist of a variety of dummy chip capacitors and leadless ceramic chip carriers (LCCC`s). Intermetallic compound (IMC) layer reaction products that form at the solder/substrate interface have been characterized and their respective growth kinetics quantified. Thicker IMC layers pose a potential reliability problem with solder joint integrity. Since the IMC layer is brittle, the likelihood of mechanical failure of a joint in service is increased. The effect of microstructure and the response of these different materials to wetting, aging and mechanical testing was also investigated. Solid-state reaction data for intermetallic formation and mechanical properties of the solder joints are reported.

  10. Numerical simulation of soldered joints and reliability analysis of PLCC components with J-shape leads

    Institute of Scientific and Technical Information of China (English)

    Zhang Liang; Xue Songbai; Lu Fangyan; Han Zongjie; Wang Jianxin

    2008-01-01

    This paper deals with a study on SnPb and lead-free soldered joint reliability of PLCC devices with different lead counts under three kinds of temperature cycle profiles, which is based on non-linear finite element method. By analyzing the stress of soldered joints, it is found that the largest stress is at the area between the soldered joints and the leads, and analysis results indicate that the von Mises stress at the location slightly increases with the increase of lead counts. For PLCC with 84 leads the soldered joints was modeled for three typical loading (273-398 K, 218-398 K and 198-398 K) in order to study the influence of acceleration factors on the reliability of soldered joints. And the estimation of equivalent plastic strain of three different lead-free solder alloys (Sn3.8Ag0.7Cu, Sn3.5Ag and Sn37Pb) was also carried out.

  11. 高速动车联轴器鼓形齿动力学特性分析和研究%Fabrication of Precise Solder Balls by Pneumatic-diaphragm Droplet Jetting Method

    Institute of Scientific and Technical Information of China (English)

    方喜峰; 石明友; 景睿; 张胜文; 王召景

    2012-01-01

    鼓形齿联轴器是动车驱动装置的关键部件之一.为了提高我国高速动车鼓形齿联轴器的设计和制造水平,实现国产化,研究了鼓形齿动力学特性.导出了自由振动方程及固有频率方程.建立了联轴器鼓形齿的有限元模型.对几种不同鼓形量的鼓形齿进行了结构动力学和强度分析,得到了联轴器鼓形齿的动态特性和接触应力.最后制造了样机,进行了模态试验,验证了理论分析的正确性.%Aimed at high uniform ultra-small solder balls requirement in area array package,a newel fabrication method was developed based on pneumatic-diaphragm droplet jetting.The principle and self-developed equipment of this method were introduced in this paper.Solder balls with diameter less than 100|xm were fabricated with a stainless steel nozzle of 50μm in diameter.Meanwhile main control parameters were studied to investigate their effects on the diameter of solder balls.The results prove that pneumatic-diaphragm droplet jetting method can fabricate solder balls with highly uniform diameter less than l00μn, good exterior quality and roundness ,which fills up the blank of domestic solder ball fabricating technology.

  12. Effect of firing conditions on thick film microstructure and solder joint strength for low-temperature, co-fired ceramic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, C.L.; Vianco, P.T.; Rejent, J.A.

    2000-01-04

    Low-temperature, co-fired ceramics (LTCC) are the substrate material-of-choice for a growing number of multi-chip module (MCM) applications. Unlike the longer-standing hybrid microcircuit technology based upon alumina substrates, the manufacturability and reliability of thick film solder joints on LTCC substrates have not been widely studied. An investigation was undertaken to fully characterize solder joints on these substrates. A surface mount test vehicle with Daisy chain electrical connections was designed and built with Dupont{trademark} 951 tape. The Dupont{trademark} 4569 thick film ink (Au76-Pt21-Pd3 wt.%) was used to establish the surface conductor pattern. The conductor pattern was fired onto the LTCC substrate in a matrix of processing conditions that included: (1) double versus triple prints, (2) dielectric window versus no window, and (3) three firing temperatures (800 C, 875 C and 950 C). Sn63-Pb37 solder paste with an RMA flux was screen printed onto the circuit boards. The appropriate packages, which included five sizes of chip capacitors and four sizes of leadless ceramic chip carriers, were placed on the circuit boards. The test vehicles were oven reflowed under a N{sub 2} atmosphere. Nonsoldered pads were removed from the test vehicles and the porosity of their thick film layers was measured using quantitative image analysis in both the transverse and short transverse directions. A significant dependence on firing temperature was recorded for porosity. The double printed substrates without a dielectric window revealed a thick film porosity of 31.2% at 800 C, 26.2% at 875 C and 20.4% at 950 C. In contrast, the thick film porosity of the triple printed substrates with a dielectric window is 24.1% at 800 C, 23.2% at 875 C and 17.6% at 950 C. These observations were compared with the shear strength of the as-fabricated chip capacitor solder joints to determine the effect of firing conditions on solder joint integrity. The denser films from the higher

  13. Development of new multicomponent Sn–Ag–Cu–Bi lead-free solders for low-cost commercial electronic assembly

    Energy Technology Data Exchange (ETDEWEB)

    El-Daly, A.A., E-mail: dreldaly11@yahoo.com [Physics Department, Faculty of Science, Zagazig Univ., Zagazig (Egypt); Center of Nanotechnology, Zagazig Univ., Zagazig (Egypt); El-Taher, A.M. [Physics Department, Faculty of Science, Zagazig Univ., Zagazig (Egypt); Center of Nanotechnology, Zagazig Univ., Zagazig (Egypt); Gouda, S. [Physics Department, Faculty of Science, Zagazig Univ., Zagazig (Egypt)

    2015-04-05

    Highlights: • Small amounts of Bi have been added into Sn–1.5Ag–0.7Cu solder. • Bi reduced the undercooling and eutectic temperature of SAC257 solder. • Bi refined the microstructure and diminishes the nucleation rate of IMCs. • Bi increased the creep resistance and fracture lifetime of the solder. • Overall SAC properties can be improved adding not more than 3 wt.% Bi. - Abstract: Eutectic Sn–Ag–Cu (SAC) solder is one of the candidate alternatives to Sn–Pb-based solder alloys. The coupling effect of both minor alloying Bi addition and reducing the amount of Ag phase have been proposed as an important approach to optimize existing and to develop new SAC solders. Characteristics of new Sn–Ag–Cu–Bi solders were analyzed and compared with those of as-solidified Sn–1.5Ag–0.7Cu (SAC157) alloy. The results of differential scanning calorimetry (DSC) indicate significant reduction of both undercooling, eutectic temperature, solidus and liquidus temperatures with the addition of Bi into SAC(157) solder, although the pasty range remains the same or slightly increased. Moreover, SAC(157) solders containing Bi were found to have a higher creep resistance (126.1 times) than SAC(157) solder at the same stress level and testing temperature. The higher creep resistance was contributed by the solid solution and precipitations strengthen effects of Bi. The precipitation of these Bi atoms or particles can significantly refine the microstructure, blocks the movement of dislocations and increases the creep resistance of Bi-containing solders. The creep life time of plain SAC(157) alloy was extremely enlarged 23.7 times with the addition of 3 wt.% Bi. Constitutive Garofalo model of creep for both SAC(157) and Sn–Ag–Cu–Bi solders was assembled based on the experimental data.

  14. Comparative study on Virtual Reality Training (VRT over Sensory Motor Training (SMT in Unilateral Chronic Osteoarthritis – A Randomized Control Trial

    Directory of Open Access Journals (Sweden)

    Fathy Abdelazim Awwad Elshazly

    2016-08-01

    Full Text Available Osteoarthritis is a common rheumatologic disease. Several non operative interventions have been described for the treatment. But the available evidences of comparing the effectiveness of Virtual reality training over sensory motor training are very few. So, the purpose of this study is to compare the effectiveness of Virtual reality training over sensory motor training in the treatment of Osteoarthritis. 60 subjects who fulfilled the inclusion and exclusion criteria were divided into three Groups (1, 2 & 3 with randomized sampling method. Group 1 treated with Virtual reality training (VRT, Group 2 treated with sensory motor training (SMT and Group 3 (control treated with conventional exercise training (CET. The duration of the treatment was three times per week for 8 weeks in all the three groups. Subjects were assessed at baseline, at 4th and 8th week. Pain Intensity by Visual Analog scale (VAS, Joint Proprioception by Perception Sense, Functional Disability by WOMAC Score, and Quality of Life by HRQOL score were measured. A statistically significant (p ≤ 0.05 difference between all the 3 groups were noted at the period of 8 week for pain intensity, joint proprioception, functional disability and quality of life. Group-1 treated with (VRT shows more significant improvement in all parameters compared with Group-2 (SMT and Group-3 (CET. In conclusion, the addition of virtual reality training to conventional training exercises could improve pain and proprioception which subsequently improve the functional level and quality of life of OA patients

  15. Nanoscale soldering of axially positioned single-walled carbon nanotubes: a molecular dynamics simulation study.

    Science.gov (United States)

    Cui, Jianlei; Yang, Lijun; Zhou, Liang; Wang, Yang

    2014-02-12

    The miniaturization of electronics devices into the nanometer scale is indispensable for next-generation semi-conductor technology. Carbon nanotubes (CNTs) are considered to be the promising candidates for future interconnection wires. To study the carbon nanotubes interconnection during nanosoldering, the melting process of nanosolder and nanosoldering process between single-walled carbon nanotubes are simulated with molecular dynamics method. As the simulation results, the melting point of 2 nm silver solder is about 605 K because of high surface energy, which is below the melting temperature of Ag bulk material. In the nanosoldering process simulations, Ag atoms may be dragged into the nanotubes to form different connection configuration, which has no apparent relationship with chirality of SWNTs. The length of core filling nanowires structure has the relationship with the diameter, and it does not become longer with the increasing diameter of SWNT. Subsequently, the dominant mechanism of was analyzed. In addition, as the heating temperature and time, respectively, increases, more Ag atoms can enter the SWNTs with longer length of Ag nanowires. And because of the strong metal bonds, less Ag atoms can remain with the tight atomic structures in the gap between SWNT and SWNT. The preferred interconnection configurations can be achieved between SWNT and SWNT in this paper.

  16. Inductive Soldering of the Junctions of the Main Superconducting Busbars of the LHC

    CERN Document Server

    Jacquemod, A; Schauf, F; Skoczen, Blazej; Tock, J P

    2004-01-01

    The Large Hadron Collider (LHC) is the next world-facility for the high energy physics community, presently under construction at CERN, Geneva. The LHC will bring into collisions intense beams of protons and ions. The main components of the LHC are the twin-aperture high-field superconducting cryomagnets that will be installed in the existing 26.7-km long tunnel. They are powered in series by superconducting Nb-Ti cables. Along the machine, about 60 000 joints between superconducting cables must be realised in-situ during the installation. Ten thousands of them, rated at 13 000 A, are involved in the powering scheme of the main dipoles and quadrupoles. To meet the requirements of the cryogenic budget, an electrical resistance at operating temperature (1.9 K) lower than 0.6 nW has to be achieved. The induction soldering technology was selected for this purpose. After a brief introduction to the LHC project, the constraints and requirements are listed. Then, the applied solution is detailed. The splices of the ...

  17. Comparative in vitro activities of SMT19969, a new antimicrobial agent, against Clostridium difficile and 350 gram-positive and gram-negative aerobic and anaerobic intestinal flora isolates.

    Science.gov (United States)

    Goldstein, Ellie J C; Citron, Diane M; Tyrrell, Kerin L; Merriam, C Vreni

    2013-10-01

    The comparative in vitro activity of SMT19969, a novel, narrow-spectrum, nonabsorbable agent, was studied against 50 ribotype-defined Clostridium difficile strains, 174 Gram-positive and 136 Gram-negative intestinal anaerobes, and 40 Gram-positive aerobes. SMT19969 was one dilution more active against C. difficile isolates (MIC range, 0.125 to 0.5 μg/ml; MIC90, 0.25 μg/ml), including ribotype 027 strains, than fidaxomicin (range, 0.06 to 1 μg/ml; MIC90, 0.5 μg/ml) and two to six dilutions lower than either vancomycin or metronidazole. SMT19969 and fidaxomicin were generally less active against Gram-negative anaerobes, especially the Bacteroides fragilis group species, than vancomycin and metronidazole, suggesting that SMT19969 has a lesser impact on the normal intestinal microbiota that maintain colonization resistance. SMT19969 showed limited activity against other Gram-positive anaerobes, including Bifidobacteria species, Eggerthella lenta, Finegoldia magna, and Peptostreptococcus anaerobius, with MIC90s of >512, >512, 64, and 64 μg/ml, respectively. Clostridium species showed various levels of susceptibility, with C. innocuum being susceptible (MIC90, 1 μg/ml) and C. ramosum and C. perfringens being nonsusceptible (MIC90, >512 μg/ml). Activity against Lactobacillus spp. (range, 0.06 to >512 μg/ml; MIC90, >512 μg/ml) was comparable to that of fidaxomicin and varied by species and strain. Gram-positive aerobic cocci (Staphylococcus aureus, Enterococcus faecalis, E. faecium, and streptococci) showed high SMT19969 MIC90 values (128 to >512 μg/ml).

  18. Science, Mathematics and Technology Teachers' Perception of School Environment: Gender Differences

    Science.gov (United States)

    Odogwu, Helen; Adeyemo, S. A.; Jimoh, J. A.; Yewonde, R. O.

    2011-01-01

    Purpose: This study seeks to examine gender differences amongst science, mathematics and technology (SMT) teachers with regards to nine school environment variables as well as the association of these variables with teachers' professional background and school characteristics. Design/methodology/approach: A questionnaire was used to collect data…

  19. Effect of Lanthanum on Driving Force for Cu6Sn5 Growth and Improvement of Solder Joint Reliability

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    By means of adding low content of rare earth element La into Sn60-Pb40 solder alloy, the growth of Cu6Sn5 intermetallic compound at the interface of solder joint is hindered, and the thermal fatigue life of solder joint is increased by 2 times. The results of thermodynamic calculation based on diffusion kinetics show that, the driving force for Cu6Sn5 growth is lowered by adding small content of La in Sn60-Pb40 solder alloy. Meanwhile, there is an effective local mole fraction range of La, in which, 0.18% is the limited value and 0.08% is the best value.

  20. Effects of Aging Treatment on Mechanical Properties of Sn-58Bi Epoxy Solder on ENEPIG-Surface-Finished PCB

    Science.gov (United States)

    Kim, Jungsoo; Myung, Woo-Ram; Jung, Seung-Boo

    2016-11-01

    The mechanical properties of Sn-58Bi epoxy solder were evaluated by low-speed shear testing as functions of aging time and temperature. To determine the effects of epoxy, the interfacial reaction and mechanical properties of both Sn-58Bi and Sn-58Bi epoxy solder were investigated after aging treatment. The chemical composition and growth kinetics of the intermetallic compound (IMC) formed at the interface between Sn-58Bi solder and electroless nickel electroless palladium immersion gold (ENEPIG) surface finish were analyzed. Sn-58Bi solder paste was applied by stencil-printing on flame retardant-4 substrate, then reflowed. Reflowed samples were aged at 85°C, 95°C, 105°C, and 115°C for up to 1000 h. (Ni,Pd)3Sn4 IMC formed between Sn-58Bi solder and ENEPIG surface finish after reflow. Ni3Sn4 and Ni3P IMCs formed at the interface between (Ni,Pd)3Sn4 IMC and ENEPIG surface finish after aging at 115°C for 300 h. The overall IMC growth rate of Sn-58Bi solder joint was higher than that of Sn-58Bi epoxy solder joint during aging. The shear strength of Sn-58Bi epoxy solder was about 2.4 times higher than that of Sn-58Bi solder due to the blocking effect of epoxy, and the shear strength decreased with increasing aging time.

  1. Effect Mechanism of Rare Earth on the Microstructures of SnAgCu Solder Joints%稀土元素对SnAgCu焊点内部组织的影响机制

    Institute of Scientific and Technical Information of China (English)

    张亮; 韩继光; 郭永环; 何成文; 袁建民

    2012-01-01

    Due to the enhancement of environmental protection in our world, the research on lead-free solders has become the important role in electronic industry, the addition of rare earth can improve the properties of lead-free solders, based on the soldering testing of lead-free solders bearing rare earth Ce, the scanning electron microscope and energy dispersive X-ray spectroscopy technology are used to investigate the effect mechanism of rare earth Ce on the microstructure of SnAgCu solder joints systematically. The results indicated that CeSn3 with different morphologies appear in the solder matrix. The chemical affinity is utilized to describe the correlation between Ce and Sn, Ag, Cu elements, it can be demonstrated that the rare earth Ce had higher affinity for Sn in the SnAgCu system in theoretically. The adsorption effect of rare earth is investigated based on ULF principle, it can be used to explain the intermetallic compounds(IMCs) refinement of SnAgCu solder joints bearing rare earth Ce. With the microstructure analysis of SnAgCuCe solder joints, it is found that the order of IMCs particles sizes is CeSn3>Cu6Sn5>Ag3Sn, in the theory, it is confirmed that the Ag3Sn particles plays an important role in the strengthen of SnAgCu solder joints, which can provide the theory support for the research of lead-free solders.%随着人们环保意识的逐渐增强,新型无铅钎料的研究成为电子工业中的研究热点,而稀土元素的添加可以显著改善钎料的性能,基于含稀土Ce无铅钎料的钎焊试验,采用扫描电镜和能谱仪研究稀土元素Ce对SnAgCu焊点内部组织的影响机制.结果表明,稀土元素在SnAgCu焊点内部以CeSn3的形式存在,且稀土相形态各异.采用化学亲和力来表征稀土元素Ce与Sn、Ag、Cu之间的内在联系,从理论上证明Ce的“亲Sn性”.采用乌尔夫原理研究稀土元素的吸附现象,解释稀土元素Ce对SnAgCu焊点内部金属间化合物的细化作用.由SnAgCuCe焊

  2. Electrodeposition of lead-free, tin-based alloy solder films

    Science.gov (United States)

    Han, Chunfen

    The dominant materials used for solders in electronic assemblies over the past 60 years have been Pb-Sn alloys. Increasing pressure from environmental and health authorities has stimulated the development of various Pb-free solders. Two of the most promising replacements are eutectic Sn-Cu and Sn-Ag-Cu alloys that are produced primarily by electrodeposition. During soldering and solid state aging (storage or in service of the electronic assemblies), interactions take place at the solder/substrate metal interface and form intermetallic compounds (IMCs) which are crucial for the reliability of the solder joints. Simple and "green" Sn-citrate and Sn-Cu-citrate solutions have been developed and optimized to electrodeposit eutectic and near eutectic Sn-Cu solder films. Sn-citrate suspensions with Cu particles and Sn-Cu-citrate suspensions with Ag nano-particles have also been developed and optimized to allow for electrochemical composite deposition of eutectic and near eutectic Sn-Cu and Sn-Ag-Cu solder films. Different plating and post-plating conditions, including solution concentration, current density, agitation, additives, and aging, have been investigated by evaluating their effects on plating rate, deposit composition and microstructure. Tri-ammonium citrate is used as the only complexing agent for Sn, Sn-Cu, and Sn-Ag-Cu deposition. Speciation diagram calculations, reduction potential calculations, and polarization studies are conducted to study Sn-citrate solution chemistry and the kinetics of Sn electrodeposition. X-ray photoelectron spectroscopy (XPS) analysis is used to identify the precipitates formed in Sn-citrate solutions at low pH. Current-controlled and potential-controlled electrochemical techniques, nucleation modeling, and surface morphology characterization techniques are applied to study the nucleation and film growth mechanism of Sn and Sn-Cu electrodeposition from Sn-citrate and Sn-Cu-citrate solutions. Reflow and aging tests for deposited Sn

  3. Laser solder repair technique for nerve anastomosis: temperatures required for optimal tensile strength

    Science.gov (United States)

    McNally-Heintzelman, Karen M.; Dawes, Judith M.; Lauto, Antonio; Parker, Anthony E.; Owen, Earl R.; Piper, James A.

    1998-01-01

    Laser-assisted repair of nerves is often unsatisfactory and has a high failure rate. Two disadvantages of laser assisted procedures are low initial strength of the resulting anastomosis and thermal damage of tissue by laser heating. Temporary or permanent stay sutures are used and fluid solders have been proposed to increase the strength of the repair. These techniques, however, have their own disadvantages including foreign body reaction and difficulty of application. To address these problems solid protein solder strips have been developed for use in conjunction with a diode laser for nerve anastomosis. The protein helps to supplement the bond, especially in the acute healing phase up to five days post- operative. Indocyanine green dye is added to the protein solder to absorb a laser wavelength (approximately 800 nm) that is poorly absorbed by water and other bodily tissues. This reduces the collateral thermal damage typically associated with other laser techniques. An investigation of the feasibility of the laser-solder repair technique in terms of required laser irradiance, tensile strength of the repair, and solder and tissue temperature is reported here. The tensile strength of repaired nerves rose steadily with laser irradiance reaching a maximum of 105 plus or minus 10 N.cm-2 at 12.7 W.cm-2. When higher laser irradiances were used the tensile strength of the resulting bonds dropped. Histopathological analysis of the laser- soldered nerves, conducted immediately after surgery, showed the solder to have adhered well to the perineurial membrane, with minimal damage to the inner axons of the nerve. The maximum temperature reached at the solder surface and at the solder/nerve interface, measured using a non-contact fiber optic radiometer and thermocouple respectively, also rose steadily with laser irradiance. At 12.7 W.cm-2, the temperatures reached at the surface and at the interface were 85 plus or minus 4 and 68 plus or minus 4 degrees Celsius respectively

  4. Intermetallic compound formation at Sn-3.0Ag-0.5Cu-1.0Zn lead-free solder alloy/Cu interface during as-soldered and as-aged conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Feng-Jiang [Department of Materials Science and Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China)]. E-mail: wangfjy@yahoo.com.cn; Yu, Zhi-Shui [Department of Materials Science and Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China); Qi, Kai [Department of Materials Science and Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China)

    2007-07-12

    Intermetallic formations of Sn-3.0Ag-0.5Cu solder alloy with additional 1.0 wt% Zn were investigated for Cu-substrate during soldering and isothermal aging. During soldering condition, the Cu{sub 5}Zn{sub 8} compound with granular-type morphology is the interfacial IMC for Sn-3.0Ag-0.5Cu-1.0Zn solder, while the Cu{sub 6}Sn{sub 5} compound with scallop-type morphology is the interfacial IMC for Sn-3.0Ag-0.5Cu solder. During thermal aging, the final interfacial structure for Sn-3.0Ag-0.5Cu-1.0Zn solder is solder/Cu{sub 5}Zn{sub 8}/Cu{sub 6}Sn{sub 5}/Cu{sub 3}Sn/Cu, different from the solder/Cu{sub 6}Sn{sub 5}/Cu{sub 3}Sn/Cu for Sn-3.0Ag-0.5Cu solder. The thickness of Cu-Sn IMC layers increases, while the thickness of Cu{sub 5}Zn{sub 8} compound layer decreases with increasing aging time due to the decomposition of the Cu{sub 5}Zn{sub 8} layer by the diffusion of Cu and Zn atoms into the solder and Cu{sub 6}Sn{sub 5} at higher aging temperature. For Sn-3.0Ag-0.5Cu-1.0Zn solder, at higher aging temperature of 150 or 175 {sup o}C, with the formation of Cu{sub 3}Sn at Cu{sub 6}Sn{sub 5}/Cu, Kirkendall voids can be observed at the interface of Cu{sub 3}Sn/Cu.

  5. Effect of diode-laser parameters on shear force of micro-joints soldered with Sn-Ag-Cu lead-free solder on Au/Ni/Cu pad

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-xin; XUE Song-bai; FANG Dian-song; JU Jin-long; HAN Zong-jie; YAO Li-hua

    2006-01-01

    Soldering experiments with Sn-3.5Ag-0.5Cu lead-free solder on Au/Ni/Cu pad were carried out by means of diode-laser and IR reflow soldering methods respectively. The influence of different heating methods as well as output power of diode-laser on shear force of micro-joints was studied and the relationship between the shear force and microstructures of micro-joints was analyzed.The results indicate that the formation of intermetallic compound Ag3Sn is the key factor to affect the shear force and the fine eutectic network structures of micro-joints as well as the dispersion morphology of fine compound Ag3Sn, in which eutectic network band is responsible for the improvement of the shear force of micro-joints soldered with Sn-Ag-Cu lead-free solder. With the increases of output power of diode-laser, the shear force and the microstructures change obviously. The eutectic network structures of micro-joints soldered with diode-laser soldering method are more homogeneous and the grains of Ag3Sn compounds are finer in the range of near optimal output power than those soldered with IR reflow soldering method, so the shear force is also higher than that using IR reflow soldering method. When the output power value of diode-laser is about 41.0 W, the shear force exhibits the highest value that is 70% higher than that using IR reflow soldering method.

  6. 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.

  7. Effects of Ga Addition on Interfacial Reactions Between Sn-Based Solders and Ni

    Science.gov (United States)

    Wang, Chao-Hong; Li, Kuan-Ting

    2016-07-01

    The use of Ga as a micro-alloying element in Sn-based solders can change the microstructure of solder joints to improve the mechanical properties, and even suppress the interfacial intermetallic compound (IMC) growth. This research investigated the effects of Ga addition (0.2-1 wt.%Ga) on the IMC formation and morphological evolution in the Sn-based solder joints with Ni substrate. In the soldering reaction at 250°C and with less than 0.2 wt.%Ga addition, the formed phase was Ni3Sn4. When the Ga addition increased to 0.5 wt.%, it changed to a thin Ni2Ga3 layer of ˜1 μm thick, which stably existed at the interface in the initial 1-h reaction. Subsequently, the whole Ni2Ga3 layer detached from the Ni substrate and drifted into the molten solder. The Ni3Sn4 phase became dominant in the later stage. Notably, the Ga addition significantly reduced the grain size of Ni3Sn4, resulting in the massive spalling of Ni3Sn4 grains. With 1 wt.%Ga addition, the Ni2Ga3 layer remained very thin with no significant growth, and it stably existed at the interface for more than 10 h. In addition, the solid-state reactions were examined at temperatures of 160°C to 200°C. With addition of 0.5 wt.%Ga, the Ni3Sn4 phase dominated the whole reaction. By contrast, with increasing to 1 wt.%Ga, only a thin Ni2Ga3 layer was found even after aging at 160°C for more than 1200 h. The 1 wt.%Ga addition in solder can effectively inhibit the Ni3Sn4 formation in soldering and the long-term aging process.

  8. High-Reliability Low-Ag-Content Sn-Ag-Cu Solder Joints for Electronics Applications

    Science.gov (United States)

    Shnawah, Dhafer Abdulameer; Said, Suhana Binti Mohd; Sabri, Mohd Faizul Mohd; Badruddin, Irfan Anjum; Che, Fa Xing

    2012-09-01

    Sn-Ag-Cu (SAC) alloy is currently recognized as the standard lead-free solder alloy for packaging of interconnects in the electronics industry, and high- Ag-content SAC alloys are the most popular choice. However, this choice has been encumbered by the fragility of the solder joints that has been observed in drop testing as well as the high cost of the Ag itself. Therefore, low-Ag-content SAC alloy was considered as a solution for both issues. However, this approach may compromise the thermal-cycling performance of the solders. Therefore, to enhance the thermal-cycling reliability of low-Ag-content SAC alloys without sacrificing their drop-impact performance, alloying elements such as Mn, Ce, Ti, Bi, In, Sb, Ni, Zn, Al, Fe, and Co were selected as additions to these alloys. However, research reports related to these modified SAC alloys are limited. To address this paucity, the present study reviews the effect of these minor alloying elements on the solder joint reliability of low-Ag-content SAC alloys in terms of thermal cycling and drop impact. Addition of Mn, Ce, Bi, and Ni to low-Ag-content SAC solder effectively improves the thermal-cycling reliability of joints without sacrificing the drop-impact performance. Taking into consideration the improvement in the bulk alloy microstructure and mechanical properties, wetting properties, and growth suppression of the interface intermetallic compound (IMC) layers, addition of Ti, In, Sb, Zn, Al, Fe, and Co to low-Ag-content SAC solder has the potential to improve the thermal-cycling reliability of joints without sacrificing the drop-impact performance. Consequently, further investigations of both thermal-cycling and drop reliability of these modified solder joints must be carried out in future work.

  9. EFFECTS OF LEAD WIDTHS AND PITCHES ON RELIABILITY OF QUAD FLAT PACKAGE (QFP) SOLDERED JOINTS

    Institute of Scientific and Technical Information of China (English)

    XUE Songbai; WU Yuxiu; HAN Zongjie; WANG Jianxin

    2007-01-01

    The finite element method(FEM) is used to analyze the effects of lead widths and pitches on reliability of soldered joints. The optimum Simulation for QFP devices is also researched. The results indicate that when the lead pitches are the same, the maximum equivalent stress of the soldered joints increases with the increasing of lead widths, while the reliability of the soldered joints reduces. When the lead widths are the same, the maximum equivalent stress of the soldered joints doesn't decrease completely with the increasing of lead pitches, a minimum value of the maximum equivalent stress values exists in all the curves. Under this condition the maximum equivalent stress of the soldered joints is relatively the least, the reliability of soldered joints is high and the assembly is excellent. The simulating results indicate the best parameter: The lead width is 0.2 mm and lead pitch is 0.3 mm (the distance between two leads is 0.1 mm), which are benefited for the micromation of QFP devices now. The minimum value of the maximum equivalent stress of soldered joints exists while lead width is 0.25 mm and lead pitch is 0.35 mm (the distance between two leads is 0.1 mm), the devices can serve for a long time and the reliability is the highest, the assembly is excellent. The simulating results also indicate the fact that the lead width is 0.15 mm and lead pitch is 0.2 mm maybe the limit of QFP, which is significant for the high lead count and micromation of assembly.

  10. 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.

  11. Effects of Ga Addition on Interfacial Reactions Between Sn-Based Solders and Ni

    Science.gov (United States)

    Wang, Chao-Hong; Li, Kuan-Ting

    2016-12-01

    The use of Ga as a micro-alloying element in Sn-based solders can change the microstructure of solder joints to improve the mechanical properties, and even suppress the interfacial intermetallic compound (IMC) growth. This research investigated the effects of Ga addition (0.2-1 wt.%Ga) on the IMC formation and morphological evolution in the Sn-based solder joints with Ni substrate. In the soldering reaction at 250°C and with less than 0.2 wt.%Ga addition, the formed phase was Ni3Sn4. When the Ga addition increased to 0.5 wt.%, it changed to a thin Ni2Ga3 layer of ˜1 μm thick, which stably existed at the interface in the initial 1-h reaction. Subsequently, the whole Ni2Ga3 layer detached from the Ni substrate and drifted into the molten solder. The Ni3Sn4 phase became dominant in the later stage. Notably, the Ga addition significantly reduced the grain size of Ni3Sn4, resulting in the massive spalling of Ni3Sn4 grains. With 1 wt.%Ga addition, the Ni2Ga3 layer remained very thin with no significant growth, and it stably existed at the interface for more than 10 h. In addition, the solid-state reactions were examined at temperatures of 160°C to 200°C. With addition of 0.5 wt.%Ga, the Ni3Sn4 phase dominated the whole reaction. By contrast, with increasing to 1 wt.%Ga, only a thin Ni2Ga3 layer was found even after aging at 160°C for more than 1200 h. The 1 wt.%Ga addition in solder can effectively inhibit the Ni3Sn4 formation in soldering and the long-term aging process.

  12. Mechanical Properties and Microstructure Investigation of Lead Free Solder

    Science.gov (United States)

    Wang, Qing; Gail, William F.; Johnson, R. Wayne; Strickland, Mark; Blanche, Jim

    2005-01-01

    While the electronics industry appears to be focusing on Sn-Ag-Cu as the alloy of choice for lead free electronics assembly, ,the exact composition varies by geographic region, supplier and user. Add to that dissolved copper and silver from the printed circuit board traces and surface finish, and there can be significant variation in the final solder joint composition. A systematic study of the mechanical and microstructural properties of Sn-Ag-Cu alloys with Ag varying from 2wt% to 4wt% and Cu varying from 0.5wt% to lSwt%, was undertaken in this research study. Different sample preparation techniques (water quenched, oil quenched and water quenched followed by reflow) were explored and the resulting microstructure compared to that of a typical reflowed lead free chip scale package (CSP) solder joint. Tensile properties (modulus, 0.2% yield strength and the ultimate tensile strength) and creep behavior of selected alloy compositions (Sn-4Ag-1 X u , Sn-4Ag-OSCu, Sn- 2Ag-1 X u , Sn-2Ag-OSCu, Sn-3.5Ag-O.SCu) were determined for three conditions: as- cast; aged for 100 hours at 125OC; and aged for 250 hours at 125OC. There was no significant difference in Young's Modulus as a function of alloy composition. After an initial decrease in modulus after 100 hours at 125"C, there was an insignificant change with further aging. The distribution of 0.2% strain yield stress and ultimate tensile strength as a function of alloy composition was more significant and decreased with aging time and temperature. The microstructures of these alloys were examined using light and scanning electron microscopy (LM and SEM) respectively and SEM based energy dispersive x-ray spectroscopy (EDS). Fracture surface and cross-section analysis were performed on the specimens after creep testing. The creep testing results and the effect of high temperature aging on mechanical properties is presented for the oil quenched samples. In general the microstructure of oil quenched specimen exhibited a

  13. Comparison of thermomigration behaviors between Pb-free flip chip solder joints and microbumps in three dimensional integrated circuits: Bump height effect

    Science.gov (United States)

    Ouyang, Fan-Yi; Jhu, Wei-Cheng

    2013-01-01

    Packaging technology is currently transition from flip chip technology to three dimensional integrated circuits (3D ICs) to meet the requirements of consumer electronic products. Compared to flip chip technology, the dimension of microbumps in 3D ICs is shrunk by a factor of 10. In this study, the behaviors of thermomigration in Pb-free solders of flip chip and 3D ICs are presented. When the bump height is 100 μm in the flip chip samples, the Sn protrusion was observed at the hot end and voids formation at the cold end. However, when the bump height is reduced to 5.8 μm in the 3D IC samples, no significant microstructural evolution of Sn was found; instead, the dissolution of Ni under-bump metallization at hot end was observed. We propose that discrepancy between flip chip solder joints and 3D IC microbumps is mainly attributed to the effect of back stress and the presence of thicker Ni under-bump metallization in the 3D IC packaging. Moreover, the critical temperature gradient in terms of different bump heights is discussed, showing below which there will be no net effect of thermomigration of Sn.

  14. Oxidation kinetics of thin copper films and wetting behaviour of copper and Organic Solderability Preservatives (OSP) with lead-free solder

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, Mauricio, E-mail: mauricio.ramirez2@de.bosch.com [Robert Bosch GmbH, Robert-Bosch-Strasse 2, 71701 Schwieberdingen (Germany); Chair for Surface Science and Corrosion, University of Erlangen-Nuremberg, Martensstrasse 7, 91058 Erlangen (Germany); Henneken, Lothar [Robert Bosch GmbH, Robert-Bosch-Strasse 2, 71701 Schwieberdingen (Germany); Virtanen, Sannakaisa [Chair for Surface Science and Corrosion, University of Erlangen-Nuremberg, Martensstrasse 7, 91058 Erlangen (Germany)

    2011-05-15

    The oxide formation on thin copper films deposited on Si wafer was studied by XPS, SEM and Sequential Electrochemical Reduction Analysis SERA. The surfaces were oxidized in air with a reflow oven as used in electronic assembly at temperatures of 100 deg. C, 155 deg. C, 200 deg. C, 230 deg. C and 260 deg. C. The SERA analyses detected only the formation of Cu{sub 2}O but the XPS analysis done for the calibration of the SERA equipment proved also the presence of a CuO layer smaller than 2 nm above the Cu{sub 2}O oxide. The oxide growth follows a power-law dependence on time within this temperature range and an activation energy of 33.1 kJ/mol was obtained. The wettability of these surfaces was also determined by measuring the contact angle between solder and copper substrate after the soldering process. A correlation between oxide thickness and wetting angle was established. It was found that the wetting is acceptable only when the oxide thickness is smaller than 16 nm. An activation energy of 27 kJ/mol was acquired for the spreading of lead free solder on oxidized copper surfaces. From wetting tests on copper surfaces protected by Organic Solderability Preservatives (OSP), it was possible to calculate the activation energy for the thermal decomposition of these protective layers.

  15. 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

    2016-08-01

    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.

  16. CO₂ laser welding of corneal cuts with albumin solder using radiometric temperature control.

    Science.gov (United States)

    Strassmann, Eyal; Livny, Eitan; Loya, Nino; Kariv, Noam; Ravid, Avi; Katzir, Abraham; Gaton, Dan D

    2013-01-01

    To examine the efficacy and reproducibility of CO₂ laser soldering of corneal cuts using real-time infrared fiber-optic radiometric control of tissue temperature in bovine eyes (in vitro) and to evaluate the duration of this procedure in rabbit eyes (in vivo). In vitro experiment: a 6-mm central perforating cut was induced in 40 fresh bovine eyes and sealed with a CO₂ laser, with or without albumin soldering, following placement of a single approximating nylon suture. A fiber-optic radiometric temperature control system for the CO₂ laser was used. Leaking pressure and histological findings were analyzed and compared between groups. In vivo experiment: following creation of a central perforation, 6 rabbit eyes were treated with a CO₂ laser with albumin solder and 6 rabbit eyes were treated with 10-0 nylon sutures. The amount of time needed for completion of the procedures was compared. In vitro experiment: effective sealing was achieved by CO₂ laser soldering. Mean (± SD) leaking pressure was 109 ± 30 mm Hg in the bovine corneas treated by the laser with albumin solder compared to 51 ± 7 mm Hg in the sutured control eyes (n = 10 each; p laser without albumin solder (48 ± 12 mm Hg) and in the cuts sealed only with albumin without laser welding (6.3 ± 4 mm Hg) than in the cuts treated with laser welding and albumin solder. In vivo experiment: mean surgical time was 140 ± 17 s in the laser-treated rabbits compared to 330 ± 30 s in the sutured controls (n = 6; p laser soldering revealed sealed corneal edges with a small gap bridged by coagulated albumin. The inflammatory reaction was minimal in contrast to the sutured controls. No thermal damage was detected at the wound edges. CO₂ laser soldering combined with the fiber-optic radiometer is an effective, reliable, and rapid tool for the closure of corneal wounds, and holds advantages over conventional suturing in terms of leaking pressure and surgical time. Copyright © 2013 S. Karger AG, Basel.

  17. Mechanical Shock Behavior of Environmentally-Benign Lead-free Solders

    Science.gov (United States)

    Yazzie, Kyle

    The mechanical behavior of Pb-free solder alloys is important, since they must maintain mechanical integrity under thermomechanical fatigue, creep, and mechanical shock conditions. Mechanical shock, in particular, has become an increasing concern in the electronics industry, since electronic packages can be subjected to mechanical shock by mishandling during manufacture or by accidental dropping. In this study, the mechanical shock behavior of Sn and Sn-Ag-Cu alloys was systematically analyzed over the strain rate range 10-3 -- 30 s-1 in bulk samples, and over 10-3 -- 12 s-1 on the single solder joint level. More importantly, the influences of solder microstructure and intermetallic compounds (IMC) on mechanical shock resistance were quantified. A thorough microstructural characterization of Sn-rich alloys was conducted using synchrotron x-ray computed tomography. The three-dimensional morphology and distribution of contiguous phases and precipitates was analyzed. A multiscale approach was utilized to characterize Sn-rich phases on the microscale with x-ray tomography and focused ion beam tomography to characterize nanoscale precipitates. A high strain rate servohydraulic test system was developed in conjunction with a modified tensile specimen geometry and a high speed camera for quantifying deformation. The effect of microstructure and applied strain rate on the local strain and strain rate distributions were quantified using digital image correlation. Necking behavior was analyzed using a novel mirror fixture, and the triaxial stresses associated with necking were corrected using a self-consistent method to obtain the true stress-true strain constitutive behavior. Fracture mechanisms were quantified as a function of strain rate. Finally, the relationship between solder microstructure and intermetallic compound layer thickness with the mechanical shock resistance of Sn-3.8Ag-0.7Cu solder joints was characterized. It was found that at low strain rates the dynamic

  18. The influence of heat treatment on properties of lead-free solders

    Directory of Open Access Journals (Sweden)

    Lýdia Trnková Rízeková

    2015-02-01

    Full Text Available The article is focused on the analysis of degradation of properties of two eutectic lead-free solders SnCu0.7 and SnAg3.5Cu0.7. The microstructures of the intermetallic compound (IMC layers at the copper substrate - solder interface were examined before and after heat treatment at 150°C for 50, 200, 500 and 1000 hours. The thickness of IMC layers of the Cu6Sn5 phase was growing with the increasing time of annealing and shown the typical scallops. For the heat treatment times of 200 hours and longer, the Cu3Sn IMC layers located near the Cu substrate were also observed. The experiments showed there is a link between the thickness of IMC layers and decrease of the shear strength of solder joints. In general, the joints made of the ternary solder showed higher shear strength before and after heat treatment in comparison to joints from solder SnCu0.7.

  19. Interfacial Reaction and Die Attach Properties of Zn-Sn High-Temperature Solders

    Science.gov (United States)

    Kim, Seongjun; Kim, Keun-Soo; Kim, Sun-Sik; Suganuma, Katsuaki

    2009-02-01

    Interfacial reaction and die attach properties of Zn- xSn ( x = 20 wt.%, 30 wt.%, and 40 wt.%) solders on an aluminum nitride-direct bonded copper substrate were investigated. At the interface with Si die coated with Au/TiN thin layers, the TiN layer did not react with the solder and worked as a good protective layer. At the interface with Cu, CuZn5, and Cu5Zn8 IMC layers were formed, the thicknesses of which can be controlled by joining conditions such as peak temperature and holding time. During multiple reflow treatments at 260°C, the die attach structure was quite stable. The shear strength of the Cu/solder/Cu joint with Zn-Sn solder was about 30 MPa to 34 MPa, which was higher than that of Pb-5Sn solder (26 MPa). The thermal conductivity of Zn-Sn alloys of 100 W/m K to 106 W/m K was sufficiently high and superior to those of Au-20Sn (59 W/m K) and Pb-5Sn (35 W/m K).

  20. Application of robust color composite fringe in flip-chip solder bump 3-D measurement

    Science.gov (United States)

    Kuo, Chung-Feng Jeffrey; Wu, Han-Cheng

    2017-04-01

    This study developed a 3-D measurement system based on flip-chip solder bump, used fringes with different modulation intensities in color channels, in order to produce color composite fringe with robustness, and proposed a multi-channel composite phase unwrapping algorithm, which uses fringe modulation weights of different channels to recombine the phase information for better measurement accuracy and stability. The experimental results showed that the average measurement accuracy is 0.43μm and the standard deviation is 1.38 μm. The results thus proved that the proposed 3-D measurement system is effective in measuring a plane with a height of 50 μm. In the flip-chip solder bump measuring experiment, different fringe modulation configurations were tested to overcome the problem of reflective coefficient between the flip-chip base board and the solder bump. The proposed system has a good measurement results and robust stability in the solder bump measurement, and can be used for the measurement of 3-D information for micron flip-chip solder bump application.

  1. Effect of Plasma Surface Finish on Wettability and Mechanical Properties of SAC305 Solder Joints

    Science.gov (United States)

    Kim, Kyoung-Ho; Koike, Junichi; Yoon, Jeong-Won; Yoo, Sehoon

    2016-12-01

    The wetting behavior, interfacial reactions, and mechanical reliability of Sn-Ag-Cu solder on a plasma-coated printed circuit board (PCB) substrate were evaluated under multiple heat-treatments. Conventional organic solderability preservative (OSP) finished PCBs were used as a reference. The plasma process created a dense and highly cross-linked polymer coating on the Cu substrates. The plasma finished samples had higher wetting forces and shorter zero-cross times than those with OSP surface finish. The OSP sample was degraded after sequential multiple heat treatments and reflow processes, whereas the solderability of the plasma finished sample was retained after multiple heat treatments. After the soldering process, similar microstructures were observed at the interfaces of the two solder joints, where the development of intermetallic compounds was observed. From ball shear tests, it was found that the shear force for the plasma substrate was consistently higher than that for the OSP substrate. Deterioration of the OSP surface finish was observed after multiple heat treatments. Overall, the plasma surface finish was superior to the conventional OSP finish with respect to wettability and joint reliability, indicating that it is a suitable material for the fabrication of complex electronic devices.

  2. Electrical Resistance of the Solder Connections for the Consolidation of the LHC Main Interconnection Splices

    CERN Document Server

    Lutum, R; Scheuerlein, C

    2013-01-01

    For the consolidation of the LHC 13 kA main interconnection splices, shunts will be soldered onto each of the 10170 splices. The solder alloy selected for this purpose is Sn60Pb40. In this context the electrical resistance of shunt to busbar lap splices has been measured in the temperature range from RT to 20 K. A cryocooler set-up has been adapted such that a test current of 150 A could be injected for accurate resistance measurements in the low nΩ range. To study the influence of the solder bulk resistivity on the overall splice resistance, connections produced with Sn96Ag4 and Sn77.2In20Ag2.8 have been studied as well. The influence of the Sn60Pb40 solder resistance is negligible when measuring the splice resistance in a longitudinal configuration over a length of 6 cm. In a transverse measurement configuration the splice resistance is significantly influenced by the solder. The connections prepared with Sn77.2In20Ag2.8 show significantly higher resistance values, as expected from the relatively high sol...

  3. In situ X-ray observation and simulation of ratcheting-fatigue interactions in solder joints

    Science.gov (United States)

    Shi, Liting; Mei, Yunhui; Chen, Gang; Chen, Xu

    2017-01-01

    Reflow voids created by solder oxidation reduce the reliability of lap joints. In situ visualization of reflow voids in Sn-3Ag-0.5Cu (SAC305) lap-shear solder joints under cyclic stressing was realized by X-ray computed tomography (CT), while the ratcheting deformation of the solder joints was monitored by a non-contact displacement detecting system (NDDS). The results revealed that the shape evolution of reflow voids in solder joints, as characterized by the sphericity of the voids, can be divided into three stages: i.e., the initial stage with a sharp drop, a stable stage, and a rapidly declining stage. A new evolution law for describing the progress of sphericity was proposed, and was further introduced into a viscoplastic constitutive model based on the OW-AF nonlinear kinematic hardening rule. The damage-coupled OW-AF model yielded an accurate estimation of the whole-life ratcheting behavior of Sn-3Ag-0.5Cu (SAC305) lap-shear solder joints. [Figure not available: see fulltext.

  4. 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.

  5. The Role of Pd in Sn-Ag-Cu Solder Interconnect Mechanical Shock Performance

    Science.gov (United States)

    Lee, Tae-Kyu; Zhou, Bite; Bieler, Thomas R.; Tseng, Chien-Fu; Duh, Jeng-Gong

    2013-02-01

    The mechanical stability of solder joints with Pd added to Sn-Ag-Cu alloy with different aging conditions was investigated in a high- G level shock environment. A test vehicle with three different strain and shock level conditions in one board was used to identify the joint stability and failure modes. The results revealed that Pd provided stability at the package-side interface with an overall shock performance improvement of over 65% compared with the Sn-Ag-Cu alloy without Pd. A dependency on the pad structure was also identified. However, the strengthening mechanism was only observed in the non-solder mask defined (NSMD) pad design, whereas the solder mask defined (SMD) pad design boards showed no improvement in shock performance with Pd-added solders. The effects of Sn grain orientation on shock performance, interconnect stability, and crack propagation path with and without Pd are discussed. The SAC305 + Pd solder joints showed more grain refinements, recrystallization, and especially mechanical twin deformation during the shock test, which provides a partial explanation for the ability of SAC305 + Pd to absorb more shock-induced energy through active deformation compared with SAC305.

  6. Interfacial reactions of Sn-Ag-Cu solders modified by minor Zn alloying addition

    Science.gov (United States)

    Kang, Sung K.; Leonard, Donovan; Shih, Da-Yuan; Gignac, Lynne; Henderson, D. W.; Cho, Sungil; Yu, Jin

    2006-03-01

    The near-ternary eutectic Sn-Ag-Cu alloys have been identified as leading Pb-free solder candidates to replace Pb-bearing solders in microelectronic applications. However, recent investigations on the processing behavior and solder joints reliability assessment have revealed several potential reliability risk factors associated with the alloy system. The formation of large Ag3Sn plates in Sn-Ag-Cu joints, especially when solidified in a relatively slow cooling rate, is one issue of concern. The implications of large Ag3Sn plates on solder joint performance and several methods to control them have been discussed in previous studies. The minor Zn addition was found to be effective in reducing the amount of undercooling required for tin solidification and thereby to suppress the formation of large Ag3Sn plates. The Zn addition also caused the changes in the bulk microstructure as well as the interfacial reaction. In this paper, an in-depth characterization of the interfacial reaction of Zn-added Sn-Ag-Cu solders on Cu and Au/Ni(P) surface finishes is reported. The effects of a Zn addition on modification of the interfacial IMCs and their growth kinetics are also discussed.

  7. Wetting and Soldering Behavior of Eutectic Au-Ge Alloy on Cu and Ni Substrates

    Science.gov (United States)

    Leinenbach, C.; Valenza, F.; Giuranno, D.; Elsener, H. R.; Jin, S.; Novakovic, R.

    2011-07-01

    Au-Ge-based alloys are interesting as novel high-temperature lead-free solders because of their low melting point, good thermal and electrical conductivity, and high corrosion resistance. In the present work, the wetting and soldering behavior of the eutectic Au-28Ge (at.%) alloy on Cu and Ni substrates have been investigated. Good wetting on both substrates with final contact angles of 13° to 14° was observed. In addition, solder joints with bond shear strength of 30 MPa to 35 MPa could be produced under controlled conditions. Cu substrates exhibit pronounced dissolution into the Au-Ge filler metal. On Ni substrates, the NiGe intermetallic compound was formed at the filler/substrate interface, which prevents dissolution of Ni into the solder. Using thin filler metal foils (25 μm), complete consumption of Ge in the reaction at the Ni interface was observed, leading to the formation of an almost pure Au layer in the soldering zone.

  8. Metal ion release from silver soldering and laser welding caused by different types of mouthwash.

    Science.gov (United States)

    Erdogan, Ayse Tuygun; Nalbantgil, Didem; Ulkur, Feyza; Sahin, Fikrettin

    2015-07-01

    To compare metal ion release from samples welded with silver soldering and laser welding when immersed into mouthwashes with different ingredients. A total of 72 samples were prepared: 36 laser welded and 36 silver soldered. Four samples were chosen from each subgroup to study the morphologic changes on their surfaces via scanning electron microscopy (SEM). Each group was further divided into four groups where the samples were submerged into mouthwash containing sodium fluoride (NaF), mouthwash containing sodium fluoride + alcohol (NaF + alcohol), mouthwash containing chlorhexidine (CHX), or artificial saliva (AS) for 24 hours and removed thereafter. Subsequently, the metal ion release from the samples was measured with inductively coupled plasma mass spectrometry (ICP-MS). The metal ion release among the solutions and the welding methods were compared. The Kruskal-Wallis and analysis of variance (ANOVA) tests were used for the group comparisons, and post hoc Dunn multiple comparison test was utilized for the two group comparisons. The level of metal ion release from samples of silver soldering was higher than from samples of laser welding. Furthermore, greater amounts of nickel, chrome, and iron were released from silver soldering. With regard to the mouthwash solutions, the lowest amounts of metal ions were released in CHX, and the highest amounts of metal ions were released in NaF + alcohol. SEM images were in accord with these findings. The laser welding should be preferred over silver soldering. CHX can be recommended for patients who have welded appliances for orthodontic reasons.

  9. Effects of Ni-coated Carbon Nanotubes addition on the electromigration of Sn–Ag–Cu solder joints

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhongbao; Zhou, Wei; Wu, Ping, E-mail: pingwu@tju.edu.cn

    2013-12-25

    Highlights: •The electromigration behaviors of the composite solder joints were investigated. •The presence of Ni altered the morphology of the IMC layer after reflow. •Carbon nanotube network was observed in solder matrix. •Current crowding occurred at the carbon nanotube networks. •The electromigration effect of composite solder joint was suppressed effectively. -- Abstract: The electromigration behaviors of line-type Cu/Sn–Ag–Cu/Cu interconnects with and without Ni-Coated multi-walled Carbon Nanotubes addition were investigated in this work. After soldering, the (Cu,Ni){sub 6}Sn{sub 5} intermetallic compounds formed at the solder/Cu interface. The electromigration analysis shows that the presence of Carbon Nanotubes can suppress the atomic diffusion in the solder induced by electromigration effectively. And finite element simulation indicates that the Carbon Nanotube networks can reduce the current density in the solder matrix, which results in the improvement of electromigration resistance of composite solders.

  10. Development of aluminum, manganese, and zinc-doped tin-silver-copper-X solders for electronic assembly

    Science.gov (United States)

    Boesenberg, Adam James

    The global electronic assembly community is striving for a robust replacement for leaded solders due to increased environmental regulations. A family of Pb-free solder alloys based on Sn-Ag-Cu (SAC) compositions has shown promise; but reliability issues in certain assembly and operating environments have arisen. Elemental (X) additions (Al, Mn, Zn) to SAC3595 were developed recently for better control of heterogeneous nucleation in solder joint solidification. Cu substrate solderability of these SAC+X alloys was investigated at concentrations between 0.01-0.25 wt. % using globule wetting balance tests due to concern about increased oxidation during reflow. Asymmetric four point bend (AFPB) tests were conducted on as-soldered and thermally aged specimens to investigate correlation between decreased shear strength and extended aging time; a common phenomenon seen in solder joints in service. Composition dependence of these X additions also was explored in simplified Cu joints by differential scanning calorimetry (DSC) and joint microstructure analysis to determine the coupling between undercooling and solidification morphology on single and multiple reflow cycles. Interesting observations by methods such as x-ray diffraction (XRD) and nano-indentation of SAC solder joints with aluminum elemental additions led to promising results and provided a possible solution to promoting heterogeneous nucleation and high reliability in these solder alloys.

  11. Compatibility of lead-free solders with lead containing surface finishes as a reliability issue in electronic assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Vianco, P.; Rejent, J. [Sandia National Labs., Albuquerque, NM (United States); Artaki, I.; Ray, U.; Finley, D.; Jackson, A. [AT and T Bell Labs., Princeton, NJ (United States)

    1996-03-01

    Enhanced performance goals and environmental restrictions have heightened the consideration for use of alternative solders as replacements for the traditional tin-lead (Sn-Pb) eutectic and near-eutectic alloys. However, the implementation of non-Pb bearing surface finishes may lag behind solder alloy development. A study was performed which examined the effect(s) of Pb contamination on the performance of Sn-Ag-Bi and Sn-Ag-Cu-Sb lead-free solders by the controlled addition of 63Sn-37Pb solder at levels of 0.5 {minus} 8.0 wt.%. Thermal analysis and ring-in-plug shear strength studies were conducted on bulk solder properties. Circuit board prototype studies centered on the performance of 20I/O SOIC gull wing joints. Both alloys exhibited declines in their melting temperatures with greater Sn-Pb additions. The ring-in-plug shear strength of the Sn-Ag-Cu-Sb solder increased slightly with Sn-Pb levels while the Sn-Ag-Bi alloy experienced a strength loss. The mechanical behavior of the SOIC (Small Outline Integrated Circuit) Sn-Ag-Bi solder joints reproduced the strength levels were insensitive to 10,106 thermal cycles. The Sn-Ag-Cu-Sb solder showed a slight decrease in the gull wing joint strengths that was sensitive to the Pb content of the surface finish.

  12. Modeling Material Properties of Lead-Free Solder Alloys

    Science.gov (United States)

    Guo, Zhanli; Saunders, Nigel; Miodownik, Peter; Schillé, Jean-Philippe

    2008-01-01

    A full set of physical and thermophysical properties for lead-free solder (LFS) alloys have been calculated, including liquidus/solidus temperatures, fraction solid, density, coefficient of thermal expansion, thermal conductivity, Young’s modulus, viscosity, and liquid surface tension, all as a function of composition and temperature (extending into the liquid state). The results have been extensively validated against data available in the literature. A detailed comparison of the properties of two LFS alloys Sn-20In-2.8Ag and Sn-5.5Zn-4.5In-3.5Bi with Sn-37Pb has been made to show the utility and need for calculations that cover a wide range of properties, including the need to consider the effect of nonequilibrium cooling. The modeling of many of these properties follows well-established procedures previously used in JMatPro software for a range of structural alloys. This paper describes an additional procedure for the calculation of the liquid surface tension for multicomponent systems, based on the Butler equation. Future software developments are reviewed, including the addition of mechanical properties, but the present calculations can already make a useful contribution to the selection of appropriate new LFS alloys.

  13. Understanding the Influence of Copper Nanoparticles on Thermal Characteristics and Microstructural Development of a Tin-Silver Solder

    Science.gov (United States)

    Lin, D. C.; Srivatsan, T. S.; Wang, G.-X.; Kovacevic, R.

    2007-10-01

    This paper presents and discusses issues relevant to solidification of a chosen lead-free solder, the eutectic Sn-3.5%Ag, and its composite counterparts. Direct temperature recordings for the no-clean solder paste during the simulated reflow process revealed a significant amount of undercooling to occur prior to the initiation of solidification of the eutectic Sn-3.5%Ag solder, which is 6.5 °C, and for the composite counterparts, it is dependent on the percentage of copper nanopowder. Temperature recordings revealed the same temperature level of 221 °C for both melting (from solid to liquid) and final solidification (after recalescence) of the Sn-3.5%Ag solder. Addition of copper nanoparticles was observed to have no appreciable influence on melting temperature of the composite solder. However, it does influence solidification of the composite solder. The addition of 0.5 wt.% copper nanoparticles lowered the solidification temperature to 219.5 °C, while addition of 1.0 wt.% copper nanoparticles lowered the solidification temperature to 217.5 °C, which is close to the melting point of the ternary eutectic Sn-Ag-Cu solder alloy, Sn-3.7Ag-0.9Cu. This indicates the copper nanoparticles are completely dissolved in the eutectic Sn-3.5%Ag solder and precipitate as the Cu6Sn5, which reinforces the eutectic solder. Optical microscopy observations revealed the addition of 1.0 wt.% of copper nanoparticles to the Sn-3.5%Ag solder results in the formation and presence of the intermetallic compound Cu6Sn5. These particles are polygonal in morphology and dispersed randomly through the solder matrix. Addition of microsized copper particles cannot completely dissolve in the eutectic solder and projects a sunflower morphology with the solid copper particle surrounded by the Cu6Sn5 intermetallic compound coupled with residual porosity present in the solder sample. Microhardness measurements revealed the addition of copper nanopowder to the eutectic Sn-3.5%Ag solder resulted in

  14. A randomised phase 1 study to investigate safety, pharmacokinetics and impact on gut microbiota following single and multiple oral doses in healthy male subjects of SMT19969, a novel agent for Clostridium difficile infections.

    Science.gov (United States)

    Vickers, Richard; Robinson, Neil; Best, Emma; Echols, Roger; Tillotson, Glenn; Wilcox, Mark

    2015-02-25

    Clostridium difficile infection (CDI) is a leading cause of diarrhoea in health care settings with symptoms ranging from mild and self-limiting to life threatening. SMT19969 is a novel, non-absorbable antibiotic currently under development for the treatment of CDI. Here we report the results from a Phase I study. A double-blind, randomized, placebo-controlled study assessing safety and tolerability of single and multiple oral doses of SMT19969 in healthy volunteers. Pharmacokinetic assessments included blood and faecal sampling. The effect of food on systemic exposure and analysis of the gut microbiota were also included. Fifty-six healthy male subjects were enrolled. Following single oral doses of up to 2,000 mg in the fasted state, plasma concentrations of SMT19969 were generally below the lower limit of quantification. In the fed state levels ranged from 0.102 to 0.296 ng/mL after single dosing and after repeat dosing at Day 10 from 0.105 to 0.305 ng/mL. Following single and multiple oral doses of SMT19969, mean daily faecal concentrations increased with increasing dose level and were significantly above the typical MIC range for C. difficile (0.06-0.5 μg/mL). At 200 mg BID, mean (± SD) faecal concentrations of 1,466 (±547) μg/g and 1,364 (±446) μg/g were determined on days 5 and 10 of dosing respectively. No notable metabolites were detected in faeces. Overall, all doses of SMT19969 were well tolerated both as single oral doses or BID oral doses for 10 days. The majority (88%) of adverse events (AEs) were classified as gastrointestinal disorders and were mild in severity, resolving without treatment. The gut microbiota was analysed in the multiple dose groups with minimal changes observed in the bacterial groups analysed except for total clostridia which were reduced to below the limit of detection by day 4 of dosing. Oral administration of SMT19969 was considered safe and well tolerated and was associated with negligible plasma concentrations after

  15. An Investigation of TiO2 Addition on Microstructure Evolution of Sn-Cu-Ni Solder Paste Composite

    Directory of Open Access Journals (Sweden)

    Saud Norainiza

    2016-01-01

    Full Text Available In this research, varying fraction of titanium oxide (TiO2 reinforcement particles was successfully incorporated into Sn-Cu-Ni solder paste in an effort to study the influence of TiO2 addition on microstructure evolution of Sn-Cu-Ni solder paste composite. Sn-Cu-Ni solder paste composite was produced by mixing TiO2 particle with Sn-Cu-Ni solder paste. The microstructure analysis was carried out by Scanning Electron Microscopy-Energy dispersive X-ray (SEM-EDX. The addition TiO2 particle helps to refine the bulk solder microstructure and suppress the intermetallic compound (IMC formation at the interface as will be discussed further.

  16. WETTING OF COPPER BY LEAD-FREE Sn-Cu SOLDERS AND SHEAR STRENGTH OF Cu – Cu JOINTS

    Directory of Open Access Journals (Sweden)

    Pavol Šebo

    2009-04-01

    Full Text Available Developing and microstructure of lead-free Sn-Cu solders containing 3, 5 and 10 wt. % of copper in bulk as well as in ribbon form is presented. Wetting of copper substrate by these solders at the temperatures 300, 350 and 400°C in air (partially in N2+10H2 during 1800 s was studied by sessile drop method. Joints Cu – solder – Cu were prepared at 300°C and 1800 s in air as well as in gas mix and their shear strength was measured. The microstructure was studied by light and scanning electron microscopy (SEM equipped with energy dispersive X-ray analyzer and standard X-ray diffraction machine. Wetting angle decreases with increasing wetting temperature. Wetting angle increased for higher (10 wt. % amount of copper in solder. Shear strength of the joints decreases with increasing the copper concentration in solder.

  17. 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.

  18. Spreading Behavior and Evolution of IMCs During Reactive Wetting of SAC Solders on Smooth and Rough Copper Substrates

    Science.gov (United States)

    Satyanarayan; Prabhu, K. N.

    2013-08-01

    The effect of surface roughness of copper substrate on the reactive wetting of Sn-Ag-Cu solder alloys and morphology of intermetallic compounds (IMCs) was investigated. The spreading behavior of solder alloys on smooth and rough Cu substrates was categorized into capillary, diffusion/reaction, and contact angle stabilization zones. The increase in substrate surface roughness improved the wetting of solder alloys, being attributed to the presence of thick Cu3Sn IMC at the interface. The morphology of IMCs transformed from long needle shaped to short protruded type with an increase in the substrate surface roughness for the Sn-0.3Ag-0.7Cu and Sn-3Ag-0.5Cu solder alloys. However, for the Sn-2.5Ag-0.5Cu solder alloy the needle-shaped IMCs transformed to the completely scallop type with increase in the substrate surface roughness. The effect of Ag content on wetting behavior was not significant.

  19. A statistical mechanics model to predict electromigration induced damage and void growth in solder interconnects

    Science.gov (United States)

    Wang, Yuexing; Yao, Yao; Keer, Leon M.

    2017-02-01

    Electromigration is an irreversible mass diffusion process with damage accumulation in microelectronic materials and components under high current density. Based on experimental observations, cotton type voids dominate the electromigration damage accumulation prior to cracking in the solder interconnect. To clarify the damage evolution process corresponding to cotton type void growth, a statistical model is proposed to predict the stochastic characteristic of void growth under high current density. An analytical solution of the cotton type void volume growth over time is obtained. The synchronous electromigration induced damage accumulation is predicted by combining the statistical void growth and the entropy increment. The electromigration induced damage evolution in solder joints is developed and applied to verify the tensile strength deterioration of solder joints due to electromigration. The predictions agree well with the experimental results.

  20. Bosonisation and Soldering of Dual Symmetries in Two and Three Dimensions

    CERN Document Server

    Banerjee, R

    1997-01-01

    We develop a technique that solders the dual aspects of some symmetry following from the bosonisation of two distinct fermionic models, thereby leading to new results which cannot be otherwise obtained. Exploiting this technique, the two dimensional chiral determinants with opposite chirality are soldered to reproduce either the usual gauge invariant expression leading to the Schwinger model or, alternatively, the Thirring model. Likewise, two apparently independent three dimensional massive Thirring models with same coupling but opposite mass signatures, in the long wavelegth limit, combine by the process of bosonisation and soldering to yield an effective massive Maxwell theory. The current bosonisation formulas are given, both in the original independent formulation as well as the effective theory, and shown to yield consistent results for the correlation functions. Similar features also hold for quantum electrodynamics in three dimensions.

  1. Multistate Degradation Mo del for Prognostics of Solder Joints Under Vibration Conditions

    Institute of Scientific and Technical Information of China (English)

    TANG Wei; JING Bo; HUANG Yifeng; SHENG Zengjin; JIAO Xiaoxuan

    2016-01-01

    This paper develops a multistate degra-dation structure of the solder joints which can be used under various vibration conditions based on nonhomoge-neous continuous-time hidden semi-Markov process. The parameters of the structure were estimated to illustrate the stochastic relationship between the degradation pro-cess and the monitoring indicator by using unsupervised learning methods. Random vibration tests on solder joints with different levels of power spectral density and fixed forms were conducted with a real time monitoring electri-cal resistance to examine the suitability of the model. It was experimentally verified that the multistate degrada-tion structure matches the experimental process reason-ably and accurately. Based on this multistate degradation model, the online prognostics of solder joint were analyzed and the results indicated that faults or failures can be de-tected timely, leading to appreciate maintenance actions scheduled to avoid catastrophic failures of electronics.

  2. 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.

  3. Universal solders for direct and powerful bonding on semiconductors, diamond, and optical materials

    Science.gov (United States)

    Mavoori, Hareesh; Ramirez, Ainissa G.; Jin, Sungho

    2001-05-01

    The surfaces of electronic and optical materials such as nitrides, carbides, oxides, sulfides, fluorides, selenides, diamond, silicon, and GaAs are known to be very difficult to bond with low melting point solders (<300 °C). We have achieved a direct and powerful bonding on these surfaces by using low temperature solders doped with rare-earth elements. The rare earth is stored in micron-scale, finely-dispersed intermetallic islands (Sn3Lu or Au4Lu), and when released, causes chemical reactions at the interface producing strong bonds. These solders directly bond to semiconductor surfaces and provide ohmic contacts. They can be useful for providing direct electrical contacts and interconnects in a variety of electronic assemblies, dimensionally stable and reliable bonding in optical fiber, laser, or thermal management assemblies.

  4. Single Image Camera Calibration in Close Range Photogrammetry for Solder Joint Analysis

    Science.gov (United States)

    Heinemann, D.; Knabner, S.; Baumgarten, D.

    2016-06-01

    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.

  5. 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

  6. Surface mount technology terms and concepts

    CERN Document Server

    Zarrow, Phil

    1997-01-01

    In today's fast-paced world of technology, keeping up with new terms and concepts can be quite a challenge. Surface Mount Technology Terms and Concepts is an invaluable reference containing over 1000 terms and definitions used in the SMT field. Each term is followed by a paragraph or two explaining the meaning and how it fits into the surface mount industry. The easy lookup and concise explanations make it ideal for those starting out in the field as well as professionals already involved in surface mount design and assembly.Glossary of over 1000 surface mount technology terms

  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. Effect of Ag on Sn–Cu and Sn–Zn lead free solders

    Directory of Open Access Journals (Sweden)

    Alam S.N.

    2015-06-01

    Full Text Available Lead and lead-containing compounds are considered as toxic substances due to their detrimental effect on the environment. Sn-based soldering systems, like Sn-Cu and Sn-Zn are considered as the most promising candidates to replace the eutectic Sn-Pb solder compared to other solders because of their low melting temperature and favorable properties. Eutectic Sn-0.7 wt.% Cu and near eutectic composition Sn-8 wt.% Zn solders have been considered here for study. For the Sn-Cu system, besides the eutectic Sn-0.7 wt.% Cu composition, Sn-1Cu and Sn-2Cu were studied. Three compositions containing Ag: Sn-2Ag-0.7Cu, Sn-2.5Ag-0.7Cu and Sn-4.5Ag-0.7Cu were also developed. Ag was added to the eutectic Sn-0.7 wt.% Cu composition in order to reduce the melting temperature of the eutectic alloy and to enhance the mechanical properties. For the Sn-Zn system, besides the Sn-8 wt.% Zn near eutectic composition, Sn-8Zn-0.05Ag, Sn-8Zn-0.1Ag and Sn-8Zn-0.2Ag solder alloys were developed. The structure and morphology of the solder alloys were analyzed using a scanning electron microscope (SEM, filed emission scanning electron microscope (FESEM, electron diffraction X-ray spectroscopy (EDX and X-ray diffraction (XRD. Thermal analysis of the alloys was also done using a differential scanning calorimeter (DSC. Trace additions of Ag have been found to significantly reduce the melting temperature of the Sn-0.7 wt.% Cu and Sn-8 wt.% Zn alloys.

  9. The microstructure and properties of as-cast Sn-Zn-Bi solder alloys

    Directory of Open Access Journals (Sweden)

    Mladenović Srba A.

    2012-01-01

    Full Text Available Research on the lead-free solders has attracted wide attention, mostly as the result of the implementation of the Directive on the Restriction of the Use of Hazardous Substances in Electrical and Electronic Equipment. The Sn-Zn solder alloys have been considered to be one of the most attractive lead-free solders due to its ability to easily replace Sn-Pb eutectic alloy without increasing the soldering temperature. Furthermore, the mechanical properties are comparable or even superior to those of Sn-Pb solder. However, other problems still persist. The solution to overcoming these drawbacks is to add a small amount of alloying elements (Bi, Ag, Cr, Cu, and Sb to the Sn-Zn alloys. Microstructure, tensile strength, and hardness of the selected Sn-Zn-Bi ternary alloys have been investigated in this study. The SEM-EDS was used for the identification of co-existing phases in the samples. The specimens’ microstructures are composed of three phases: Sn-rich solid solution as the matrix, Bi-phase and Zn-rich phase. The Bi precipitates are formed around the Sn-dendrit grains as well as around the Zn-rich phase. The amount of Bi segregation increases with the increase of Bi content. The Sn-Zn-Bi alloys exhibit the high tensile strength and hardness, but the values of these mechanical properties decrease with the increase of Bi content, as well as the reduction of Zn content. The results presented in this paper may offer further knowledge of the effects various parameters have on the properties of lead-free Sn-Zn-Bi solders.

  10. 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.

  11. Suppressing tin whisker growth in lead-free solders and platings

    Science.gov (United States)

    Hoffman, Elizabeth N; Lam, Poh-Sang

    2014-04-29

    A process of irradiation Sn containing Pb-free solder to mitigate whisker formation and growth thereon is provided. The use of gamma radiation such as cobalt-60 has been applied to a substrate of Sn on copper has been found to change the morphology of the crystalline whisker growth to a more truncated hillock pattern. The change in morphology greatly reduces the tendency of whiskers to contribute to electrical short-circuits being used as a Pb-free solder system on a copper substrate.

  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

    Traditionally assessment of reliability of electrical components is done by classical reliability techniques using failure rates as the basic measure of reliability. In this paper a structural reliability approach is applied in order to include all relevant uncertainties and to give a more detailed...... 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...

  13. 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

    , 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...... by an appropriate cleaning. Selective soldering process generates significantly higher levels of residues compared to the wave and reflow process. For conformal coated PCBAs, the contamination levels generated from the tested wave and selective soldering process are found to be enough to generate blisters under...

  14. Sensitivity of Solder Joint Fatigue to Sources of Variation in Advanced Vehicular Power Electronics Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Vlahinos, A.; O' Keefe, M.

    2010-06-01

    This paper demonstrates a methodology for taking variation into account in thermal and fatigue analyses of the die attach for an inverter of an electric traction drive vehicle. This method can be used to understand how variation and mission profile affect parameters of interest in a design. Three parameters are varied to represent manufacturing, material, and loading variation: solder joint voiding, aluminum nitride substrate thermal conductivity, and heat generation at the integrated gate bipolar transistor. The influence of these parameters on temperature and solder fatigue life is presented. The heat generation loading variation shows the largest influence on the results for the assumptions used in this problem setup.

  15. Finite element simulation for mechanical response of surface mounted solder joints under different temperature cycling

    Institute of Scientific and Technical Information of China (English)

    马鑫; 钱乙余

    2001-01-01

    Nonlinear finite element simulation for mechanical response of surface mounted solder joint under different temperature cycling was carried out. Seven sets of parameters were used in order to evaluate the influence of temperature cycling profile parameters. The results show that temperature cycling history has significant effect on the stress response of the solder joint. Based on the concept of relative damage stress proposed by the authors, it is found that enough high temperature holding time is necessary for designing the temperature cycling profile in accelerated thermal fatigue test.

  16. Observation of amorphous chromium in modified C4 flip chip solder joints after thermal stress testing

    Energy Technology Data Exchange (ETDEWEB)

    Hooghan, T.K.; Nakahara, S.; Hooghan, K.; Privette, R.W.; Bachman, M.A.; Moyer, R.S

    2003-08-01

    Flip chip reliability was evaluated using thermal stress tests at 150 deg. C. Electrical failures of flip chip devices were found to occur at the solder/under-bump-metallization interface by forming a porous amorphous chromium layer. The formation of the porous amorphous layer responsible for electrical failures resulted from the outdiffusion of copper atoms from a copper-chromium co-deposit, used as one of the under-bump-metallization layers. A strong interaction of Cu with the Sn component of the solder is the driving force of the Cu outdiffusion.

  17. Effect of Electromigration on the Type of Drop Failure of Sn-3.0Ag-0.5Cu Solder Joints in PBGA Packages

    Science.gov (United States)

    Huang, M. L.; Zhao, N.

    2015-10-01

    Board-level drop tests of plastic ball grid array (PBGA) packages were performed in accordance with the Joint Electron Devices Engineering Council standard to investigate the effect of electromigration (EM) on the drop reliability of Sn-3.0Ag-0.5Cu solder joints with two substrate surface finishes, organic solderability preservative (OSP) and electroless nickel electroless palladium immersion gold (ENEPIG). In the as-soldered state, drop failures occurred at the substrate sides only, with cracks propagating within the interfacial intermetallic compound (IMC) layer for OSP solder joints and along the IMC/Ni-P interface for ENEPIG solder joints. The drop lifetime of OSP solder joints was approximately twice that of ENEPIG joints. EM had an important effect on crack formation and drop lifetime of the PBGA solder joints. ENEPIG solder joints performed better in drop reliability tests after EM, that is, the drop lifetime of ENEPIG joints decreased by 43% whereas that of OSP solder joints decreased by 91%, compared with the as-soldered cases. The more serious polarity effect, i.e., excessive growth of the interfacial IMC at the anode, was responsible for the sharper decrease in drop lifetime. The different types of drop failure of PBGA solder joints before and after EM, including the position of initiation and the propagation path of cracks, are discussed on the basis of the growth behavior of interfacial IMC.

  18. Intermetallic compound formation in Sn-Co-Cu, Sn-Ag-Cu and eutectic Sn-Cu solder joints on electroless Ni(P) immersion Au surface finish after reflow soldering

    Energy Technology Data Exchange (ETDEWEB)

    Sun Peng [Key State Lab for New Displays and System Integration (Chinese Ministry of Education), SMIT Center, Shanghai University, 200072 Shanghai (China) and Department of Microtechnology and Nanoscience, SMIT Center, Chalmers University of Technology, 412-96 Goeteborg (Sweden)]. E-mail: peng.sun@mc2.chalmers.se; Andersson, Cristina [Department of Microtechnology and Nanoscience, SMIT Center, Chalmers University of Technology, 412-96 Goeteborg (Sweden); Wei Xicheng [Key State Lab for New Displays and System Integration (Chinese Ministry of Education), SMIT Center, Shanghai University, 200072 Shanghai (China); Cheng Zhaonian [Department of Microtechnology and Nanoscience, SMIT Center, Chalmers University of Technology, 412-96 Goeteborg (Sweden); Shangguan Dongkai [Flextronics International, San Jose, CA (United States); Liu Johan [Key State Lab for New Displays and System Integration (Chinese Ministry of Education), SMIT Center, Shanghai University, 200072 Shanghai (China); Department of Microtechnology and Nanoscience, SMIT Center, Chalmers University of Technology, 412-96 Goeteborg (Sweden)

    2006-11-25

    The interfacial reactions between Sn-0.4Co-0.7Cu eutectic alloy and immersion Au/electroless Ni(P)/Cu substrate were investigated after reflow soldering at 260 deg. C for 2 min. Common Sn-4.0Ag-0.5Cu and eutectic Sn-0.7Cu solders were used as reference. Two types of intermetallic compounds (IMC) were found in the solder matrix of the Sn-0.4Co-0.7Cu alloy, namely coarser CoSn{sub 2} and finer Cu{sub 6}Sn{sub 5} particles, while only one ternary (Cu, Ni){sub 6}Sn{sub 5} interfacial compound was detected between the solder alloy and the electroless nickel and immersion gold (ENIG) coated substrate. The same trend was also observed for the Sn-Ag-Cu and Sn-Cu solder joints. Compared with the CoSn{sub 2} particles found in the Sn-Co-Cu solder and the Ag{sub 3}Sn particles found in the Sn-Ag-Cu solder, the Cu{sub 6}Sn{sub 5} particles found in both solder systems exhibited finer structure and more uniform distribution. It was noted that the thickness of the interfacial IMCs for the Sn-Co-Cu, Sn-Ag-Cu and Sn-Cu alloys was 3.5 {mu}m, 4.3 {mu}m and 4.1 {mu}m, respectively, as a result of longer reflow time above the alloy's melting temperature since the Sn-Ag-Cu solder alloy has the lowest melting point.

  19. Microstructural characterization and mechanical property of active soldering anodized 6061 Al alloy using Sn-3.5Ag-xTi active solders

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei-Lin, E-mail: wangwl77@gmail.com; Tsai, Yi-Chia, E-mail: tij@itri.org.tw

    2012-06-15

    Active solders Sn-3.5Ag-xTi varied from x = 0 to 6 wt.% Ti addition were prepared by vacuum arc re-melting and the resultant phase formation and variation of microstructure with titanium concentration were analyzed using X-ray diffraction, optical microscopy and scanning electron microscopy. The Sn-3.5Ag-xTi active solders are used as metallic filler to join with anodized 6061 Al alloy for potential applications of providing a higher heat conduction path. Their joints and mechanical properties were characterized and evaluated in terms of titanium content. The mechanical property of joints was measured by shear testing. The joint strength was very dependent on the titanium content. Solder with a 0.5 wt.% Ti addition can successfully wet and bond to the anodized aluminum oxide layers of Al alloy and posses a shear strength of 16.28 {+-} 0.64 MPa. The maximum bonding strength reached 22.24 {+-} 0.70 MPa at a 3 wt.% Ti addition. Interfacial reaction phase and chemical composition were identified by a transmission electron microscope with energy dispersive spectrometer. Results showed that the Ti element reacts with anodized aluminum oxide to form Al{sub 3}Ti-rich and Al{sub 3}Ti phases at the joint interfaces. - Highlights: Black-Right-Pointing-Pointer Active solder joining of anodized Al alloy needs 0.5 wt.% Ti addition for Sn-3.5Ag. Black-Right-Pointing-Pointer The maximum bonding strength occurs at 3 wt.% Ti addition. Black-Right-Pointing-Pointer The Ti reacts with anodized Al oxide to form Al{sub 3}Ti-rich and Al{sub 3}Ti at joint interface.

  20. 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.

  1. Determination of Average Failure Time and Microstructural Analysis of Sn-Ag-Bi-In Solder Under Electromigration

    Science.gov (United States)

    Wu, Albert T.; Sun, K. H.

    2009-12-01

    Despite the extensive use of Sn-Ag-Cu as a Pb-free solder alloy, its melting point is significantly higher than that of eutectic Sn-Pb solder. Sn-Ag-Bi-In solder is an alternative Pb-free solder, with a melting temperature close to that of eutectic Sn-Pb. This study elucidates the electromigration behavior of Sn-Ag-Bi-In solder and then compares the results with those of the Sn-Ag-Bi system. The behavior of Pb-free Sn-Ag-Bi-In solder strips under electromigration is examined by preparing them in Si (001) U-grooves. The samples are then tested under various temperatures and current densities. Although the compounds thicken near both electrodes with current stressing, the thickness at the anode exceeds that at the cathode. Experimental results of the average failure time indicate that Sn-Ag-Bi-In solder has a longer lifetime than does Sn-Ag-Bi, which is attributed to the ζ phase. Additionally, the ζ phase dissolved by the current in the early stage replenishes the outgoing atomic flux. These atomic fluxes also enhance the growth of abnormally large particles in the middle of the strips. Field-emission electron probe microanalysis (FE-EPMA) results indicate that the amount of indium is reduced after the ζ phase near the cathode is exhausted for extended current stressing time.

  2. Comparison of Extensive Thermal Cycling Effects on Microstructure Development in Micro-alloyed Sn-Ag-Cu Solder Joints

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Iver E.; Boesenberg, Adam; Harringa, Joel; Riegner, David; Steinmetz, Andrew; Hillman, David

    2011-09-28

    Pb-free solder alloys based on the Sn-Ag-Cu (SAC) ternary eutectic have promise for widespread adoption across assembly conditions and operating environments, but enhanced microstructural control is needed. Micro-alloying with elements such as Zn was demonstrated for promoting a preferred solidification path and joint microstructure earlier in simple (Cu/Cu) solder joints studies for different cooling rates. This beneficial behavior now has been verified in reworked ball grid array (BGA) joints, using dissimilar SAC305 (Sn-3.0Ag-0.5Cu, wt.%) solder paste. After industrial assembly, BGA components joined with Sn-3.5Ag-0.74Cu-0.21Zn solder were tested in thermal cycling (-55 C/+125 C) along with baseline SAC305 BGA joints beyond 3000 cycles with continuous failure monitoring. Weibull analysis of the results demonstrated that BGA components joined with SAC + Zn/SAC305 have less joint integrity than SAC305 joints, but their lifetime is sufficient for severe applications in consumer, defense, and avionics electronic product field environments. Failure analysis of the BGA joints revealed that cracking did not deviate from the typical top area (BGA component side) of each joint, in spite of different Ag3Sn blade content. Thus, SAC + Zn solder has not shown any advantage over SAC305 solder in these thermal cycling trials, but other characteristics of SAC + Zn solder may make it more attractive for use across the full range of harsh conditions of avionics or defense applications.

  3. Wetting Behavior in Ultrasonic Vibration-Assisted Brazing of Aluminum to Graphite Using Sn-Ag-Ti Active Solder

    Science.gov (United States)

    Yu, Wei-Yuan; Liu, Sen-Hui; Liu, Xin-Ya; Shao, Jia-Lin; Liu, Min-Pen

    2015-03-01

    In this study, Sn-Ag-Ti ternary alloy has been used as the active solder to braze pure aluminum and graphite in atmospheric conditions using ultrasonic vibration as an aid. The authors studied the formation, composition and decomposition temperature of the surface oxides of the active solder under atmospheric conditions. In addition, the wettability of Sn-5Ag-8Ti active solder on the surface of pure aluminum and graphite has also been studied. The results showed that the major components presented in the surface oxides formed on the Sn-5Ag-8Ti active solder under ambient conditions are TiO, TiO2, Ti2O3, Ti3O5 and SnO2. Apart from AgO and Ag2O2, which can be decomposed at the brazing temperature (773 K), other oxides will not be decomposed. The oxide layer comprises composite oxides and it forms a compact layer with a certain thickness to enclose the melted solder, which will prevent the liquid solder from wetting the base metals at the brazing temperature. After ultrasonic vibration, the oxide layer was destroyed and the liquid solder was able to wet and spread out around the base materials. Furthermore, better wettability of the active solder was observed on the surface of graphite and pure aluminum at the brazing temperature of 773-823 K using ultrasonic waves. The ultrasonic wave acts as the dominant driving factor which promotes the wetting and spreading of the liquid solder on the surface of graphite and aluminum to achieve a stable and reliable brazed joint.

  4. 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.

  5. Assessment of Solder Interconnect Integrity in Dismantled Electronic Components from N57 and B61 Tube-Type Radars

    Energy Technology Data Exchange (ETDEWEB)

    Rejent, J.A.; Vianco, P.T.; Woodrum, R.A.

    1999-07-01

    Aging analyses were performed on solder joints from two radar units: (1) a laboratory, N57 tube-type radar unit and (2) a field-returned, B61-0, tube-type radar unit. The cumulative temperature environments experienced by the units during aging were calculated from the intermetallic compound layer thickness and the mean Pb-rich phase particle size metrics for solder joints in the units, assuming an aging time of 35 years for both radars. Baseline aging metrics were obtained from a laboratory test vehicle assembled at AS/FM and T; the aging kinetics of both metrics were calculated from isothermal aging experiments. The N57 radar unit interconnect board solder joints exhibited very little aging. The eyelet solder joints did show cracking that most likely occurred at the time of assembly. The eyelet, SA1126 connector solder joints, showed some delamination between the Cu pad and underlying laminate. The B61 field-returned radar solder joints showed a nominal degree of aging. Cracking of the eyelet solder joints was observed. The Pb-rich phase particle measurements indicated additional aging of the interconnects as a result of residual stresses. Cracking of the terminal pole connector, pin-to-pin solder joint was observed; but it was not believed to jeopardize the electrical functionality of the interconnect. Extending the stockpile lifetime of the B61 tube-type radar by an additional 20 years would not be impacted by the reliability of the solder joints with respect to further growth of the intermetallic compound layer. Additional coarsening of the Pb-rich phase will increase the joints' sensitivity to thermomechanical fatigue.

  6. 内镜下微创治疗消化道SMT 94例的临床分析%Endoscopic treatment for gastrointestinal submucosal tumor:A clinical analysis of 94 patients

    Institute of Scientific and Technical Information of China (English)

    黄丽韫; 毛华; 余建林

    2014-01-01

    Objective To discuss the indication, technique, effect, and safety of endoscopic treatment of SMT in gastrointestinal tract. Methods Endoscopic therapy was performed in 94 patients with gastrointestinal diagnosed by endoscopy. 22 cases underwent EMR; 61 cases were treated with ESD; MBM was exercised on 7 cases; and nylon endoloop ligature were carried out on 4 cases. Results Complete resection was achieved on 86 cases, and 1 case was excised partially. 1 patient with SMT was transferred to open surgery. Lumps of 4 SMT cases treated by nylon endoloop ligature were found disappeared at subsequent visit after a month. All patients were followed up for one year, and no recurrence was found. Conclusions Gastrointestinal SMT can be completely resected by EMR, ESD and MBM. Nylon endoloop ligature can be used for the treatment of SMT in position difficult to deal with. Endoscopic therapy is relatively safe, effective, and minimal invasion for SMT.%目的:探讨内镜下治疗消化道黏膜下肿物(SMT)的指征、方法、疗效及安全性。方法:对内镜检查中发现的94例消化道SMT行内镜微创治疗,22例行黏膜切除术(EMR),61例行黏膜剥离术(ESD),7例行多环黏膜切除术(MBM),4例行尼龙绳套扎治疗。结果:完全切除86例,残存切除1例,术中穿孔1例,转外科手术;4例SMT尼龙绳套扎治疗,1个月后复查时肿物已清除。所有病例随访1年,均无复发。结论:消化道SMT可应用EMR、ESD、MBM完整切除,对于较难处理部位的SMT可试行尼龙绳套扎术治疗,内镜下治疗SMT创伤小、安全、疗效好。

  7. Applications of Image Processing Techniques in Solder Joint Detection%图像处理技术在焊点检测中的应用

    Institute of Scientific and Technical Information of China (English)

    孙晓婷

    2012-01-01

      The technology of image processing is introduced in the detecting of solder joint for inspecting the quality of solder joints: image filtering and enhancing by LOG, image segmentation based on that optimal threshold method, then morphology processing was performed, finally after the characteristic parameter have been acquired, they are used for the object image analysis by particle analysis .The experiment shows that the above method is simple operation,high efficiency and good result.%  将图像处理技术引入PCB焊点检测中,对焊点进检测:用LOG算子进行图像滤波和增强,然后利用最优阈值法进行图像分割,接下来进行形态学处理,最后用颗粒分析获得目标特征参数实现焊点分析。经过试验表明,该系统操作简单,效率高,可以很好地实现对焊点质量的检测。

  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. Length-Dependent Electromigration Behavior of Sn58Bi Solder and Critical Length of Electromigration

    Science.gov (United States)

    Zhao, Xu; Muraoka, Mikio; Saka, Masumi

    2017-02-01

    On the basis of a developed test structure, electromigration (EM) tests of Sn58Bi solder strips with lengths of 50 μm, 100 μm, and 150 μm were simultaneously conducted at a current density of 27 kA/cm2 at 373 K. Length-dependent EM behavior was detected, and the mechanism is discussed. Bi atoms were segregated to the anode side more easily as the strip length increased, which resulted in the formation of a thicker Bi-rich layer or Sn-Bi mixed hillocks. The results reveal the existence of back flow that depends on the solder joint length. The back flow is most likely caused by an oxide layer formed on the Sn58Bi solder. By measuring the thicknesses of the Bi-rich layers, the Bi drift velocities were obtained. The critical length of the solder joint and the critical product of the length and the current density were estimated to be 16 μm and 43 A/cm, respectively. This observation will assist design of advanced electronic devices to anticipate EM reliability.

  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

    the equilibrium calculations by Scheil solidification simulations and optimization. A feasibility study has been carried out for the replacement of high-lead-containing solders with the focus on surface tension, natural radius of curvature, oxidation resistance, intermetallic compound formation, and environmental...

  11. Corrosion reliability of lead-free solder systems used in electronics

    DEFF Research Database (Denmark)

    Li, Jing-Feng; Verdingovas, Vadimas; Medgyes, Balint

    2017-01-01

    .5 wt% sodium chloride electrolyte at room temperature. Microstructure of the solder alloys and corrosion surface morphology was evaluated using light optical microscope (LOM) scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). During the potentiostatic...

  12. 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

    significantly higher levels of residues compared to the wave and reflow process. For conformal coated PCBAs, the contamination levels generated from the tested wave and selective soldering process are found to be enough to generate blisters under exposure to high humidity levels. Originality/value – Although...

  13. Relative effect of solder flux chemistry on the humidity related failures in electronics

    DEFF Research Database (Denmark)

    Verdingovas, Vadimas; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-01-01

    of printed circuit boards under humid conditions. Originality/value - The classification of solder flux systems according to IPC J-STD-004 standard does not specify the WOAs in the flux; however, ranking of the flux systems based on the hygroscopic property of activators would be useful information when...

  14. 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...

  15. 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.

  16. 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.

  17. 30 CFR 75.1106 - Welding, cutting, or soldering with arc or flame underground.

    Science.gov (United States)

    2010-07-01

    ... flame underground. 75.1106 Section 75.1106 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106 Welding, cutting, or soldering with arc or flame underground. All welding, cutting, or...

  18. Au-SN Flip-Chip Solder Bump for Microelectronic and Optoelectronic Applications

    CERN Document Server

    Yoon, Jeong-Won; Koo, Ja-Myeong; Jung, Seung-Boo

    2007-01-01

    As an alternative to the time-consuming solder pre-forms and pastes currently used, a co-electroplating method of eutectic Au-Sn alloy was used in this study. Using a co-electroplating process, it was possible to plate the Au-Sn solder directly onto a wafer at or near the eutectic composition from a single solution. Two distinct phases, Au5Sn and AuSn, were deposited at a composition of 30at.%Sn. The Au-Sn flip-chip joints were formed at 300 and 400 degrees without using any flux. In the case where the samples were reflowed at 300 degrees, only an (Au,Ni)3Sn2 IMC layer formed at the interface between the Au-Sn solder and Ni UBM. On the other hand, two IMC layers, (Au,Ni)3Sn2 and (Au,Ni)3Sn, were found at the interfaces of the samples reflowed at 400 degrees. As the reflow time increased, the thickness of the (Au,Ni)3Sn2 and (Au,Ni)3Sn IMC layers formed at the interface increased and the eutectic lamellae in the bulk solder coarsened.

  19. 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...

  20. The effect of ultrasound on the gold plating of silica nanoparticles for use in composite solders.

    Science.gov (United States)

    Cobley, A J; Mason, T J; Alarjah, M; Ashayer, R; Mannan, S H

    2011-01-01

    In order to produce electronic devices that can survive harsh environments it is essential that the solder joints are very reliable and this has led to the development of composite solders. One approach to the manufacture of such solders is to disperse silica nanoparticles into it to improve their mechanical and fatigue characteristics. However, this is difficult to achieve using bare silica particles because they are not "wettable" in the solder matrix and so cannot be dispersed efficiently. In an attempt to alleviate this issue it has been found that if the silica nanoparticles are first plated with gold then this problem of wetting can, to some extent, be overcome. However, the particles must be completely encapsulated with gold which, using the method previously described by workers at Kings College London, was found to be difficult to accomplish. In this short communication the effect of ultrasound on the gold coverage is described. Different frequencies of ultrasound were used (20, 850 and 1176 kHz) and it was found that higher frequencies of ultrasound improved the coverage and dispersion of the gold nanoparticles over silica during the seeding step compared to simple mechanical agitation. This subsequently led to a more complete encapsulation of gold in the plating stage.

  1. Relative Damage Stress: Dominant Mechanical Factor for the Failure of Soldered Joints under Temperature Cycling

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    By temperature normalization of the concept of equivalent damage stress proposed by Lemaitre,a new concept of relative damage stress has been put forward as the dominant mechanical factor for the failure of soldered joints under temperature cycling. Finite element numerical simulation results showed that the highest value of relative damage stress occurred at the high temperaturehold time during temperature cycling history.

  2. Role of grain orientation in the failure of Sn-based solder joints under thermomechanical fatigue

    Institute of Scientific and Technical Information of China (English)

    Jing HAN; Hongtao CHEN; Mingyu LI

    2012-01-01

    A small Pb-free solder joint exhibits an extremely strong anisotropy due to the bodycentered tetragonal (BCT) lattice structure of β-Sn.Grain orientations can significantly influence the failure mode of Pb-free solder joints under thermomechanical fatigue (TMF) due to the coefficient of thermal expansion (CTE) mismatch of β-Sn grains.The research work in this paper focused on the microstructure and damage evolution of Sn3.0Ag0.5Cu BGA packages as well as individual Sn3.5Ag solder joints without constraints introduced by the package structure under TMF tests.The microstructure and damage evolution in cross-sections of solder joints under thermomechanical shock tests were characterized using optical microscopy with cross-polarized light and scanning electron microscopy (SEM),and orientations of Sn grains were determined by orientation imaging microscopy (OIM).During TMF,obvious recrystallization regions were observed with different thermomechanical responses depending on Sn grain orientations.It indicates that substantial stresses can build up at grain boundaries,leading to significant grain boundary sliding.The results show that recrystallized grains prefer to nucleate along pre-existing high-angle grain boundaries and fatigue cracks tend to propagate intergranularly in recrystallized regions,leading to an accelerated damage after recrystallization.

  3. Microstructure evolution in a Pb-free solder alloy during mechanical fatigue

    NARCIS (Netherlands)

    Matin, M. A.; Vellinga, W. P.; Geers, M. G. D.

    2006-01-01

    Microstructural evolution in a Sn-rich eutectic Sn-3.8Ag-0.7Cu solder alloy has been investigated in low cycle mechanical fatigue. Inhomogeneity in deformation occurred on a grain scale (determined by grain orientation and plastic anisotropy of Sn) and on a subgrain scale where persistent slip bands

  4. Microstructure and mechanical behavior of novel rare earth-containing Pb-Free solders

    Science.gov (United States)

    Dudek, M. A.; Sidhu, R. S.; Chawla, N.; Renavikar, M.

    2006-12-01

    Sn-rich solders have been shown to have superior mechanical properties when compared to the Pb-Sn system. Much work remains to be done in developing these materials for electronic packaging. In this paper, we report on the microstructure and mechanical properties of La-containing Sn-3.9Ag-0.7Cu alloys. The addition of small amounts of La (up to 0.5 wt.%) to Sn-Ag-Cu refined the microstructure by decreasing the length and spacing of the Sn dendrites and decreased the thickness of the Cu6Sn5 intermetallic layer at the Cu/solder interface. As a result of the change in the microstructure, Sn-Ag-Cu alloys with La additions exhibited a small decrease in ultimate shear strength but significantly higher elongations compared with Sn-Ag-Cu. The influence of LaSn3 intermetallics on microstructural refinement and damage evolution in these novel solders is discussed. Our results have profound implications for improving the mechanical shock resistance of Pb-free solders.

  5. 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

    the equilibrium calculations by Scheil solidification simulations and optimization. A feasibility study has been carried out for the replacement of high-lead-containing solders with the focus on surface tension, natural radius of curvature, oxidation resistance, intermetallic compound formation, and environmental...

  6. The use of process plasmas for cleaning PCB substrates for fluxless soldering of electronic assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Philpott, J.D

    1999-12-01

    In this thesis the ability of single and multiple gas plasmas to improve the solderability of PCB substrates, and hence allow the removal of flux from the soldering process for electronic assemblies has been investigated. It has been shown that asymmetric electrode plasma chambers allow the use of single gas plasmas for this purpose due to their greater efficiency compared to symmetric systems. It has also been shown that the use of triple gas plasmas results in improved cleaning ability when using symmetric electrode systems. Dynamic contact angle (DCA) analysis was the primary analytical technique used in this work. This technique produces two contact angles, advancing and receding. The advancing contact angle determines the surface energy of a solid. It has been shown using Auger analysis that contact angles of approximately 48 deg indicate low levels of hydrocarbon contamination. It has also been shown that plasma cleaning processes giving advancing contact angles of this magnitude result in the ability to solder Hot Air Solder Leveled (HASL) PCB substrates without the use of flux. In addition it has been shown that, whilst it is possible to reduce the advancing contact angle of copper substrates considerably, the reduction is not as great as for HASL substrates. Analytical models of RF plasma chambers have also been reviewed, and these adapted for the plasma chambers used in this work. The experimental work carried out in this research also shows that these models hold true. (author)

  7. Damage Model for Reliability Assessment of Solder Joints in Wind Turbines

    DEFF Research Database (Denmark)

    Kostandyan, Erik; Sørensen, John Dalsgaard

    2012-01-01

    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...

  8. Microstructure evolution in a Pb-free solder alloy during mechanical fatigue

    NARCIS (Netherlands)

    Matin, M. A.; Vellinga, W. P.; Geers, M. G. D.

    2006-01-01

    Microstructural evolution in a Sn-rich eutectic Sn-3.8Ag-0.7Cu solder alloy has been investigated in low cycle mechanical fatigue. Inhomogeneity in deformation occurred on a grain scale (determined by grain orientation and plastic anisotropy of Sn) and on a subgrain scale where persistent slip bands

  9. Interfacial reaction of eutectic AuSi solder with Si (100) and Si (111) surfaces

    Science.gov (United States)

    Jang, Jin-Wook; Hayes, Scott; Lin, Jong-Kai; Frear, Darrel R.

    2004-06-01

    The dissolution behavior of Si (100) and (111) dies by eutectic AuSi solder was investigated. On the Si (100) surface, the dissolution primarily occurred by the formation of craters resulting in a rough surface. The dissolution of the Si (111) resulted in a relatively smooth surface. The morphology of the Si (100) surface during a AuSi soldering reaction exhibited more time-dependent behavior and the etching craters on a Si (100) surface grew larger with time whereas Si (111) did not significantly change. This difference was ascribed to the surface energy differences between Si (111) and (100) surfaces that resulted in the two- and three-dimensional dissolution behaviors, respectively. This difference plays an important role in the formation of voids during the AuSi die bonding. The etching craters on Si (100) act as a AuSi solder sink and the regions surrounded by etch pits tend to become voids. For Si (111), flat surfaces were observed in the voided regions. Cross section analysis showed that no solder reaction occurred in the voided region of the Si (111) surface. This suggests the possibility of the formation of a thin inert layer in a potentially voided region prior to assembly. To achieve void-free die bonding, different parameters must be adjusted to the Si (100) and Si (111) surfaces with the AuSi alloy.

  10. Nucleation and Growth of Tin in Pb-Free Solder Joints

    Science.gov (United States)

    Gourlay, C. M.; Belyakov, S. A.; Ma, Z. L.; Xian, J. W.

    2015-08-01

    The solidification of Pb-free solder joints is overviewed with a focus on the formation of the βSn grain structure and grain orientations. Three solders commonly used in electronics manufacturing, Sn-3Ag-0.5Cu, Sn-3.5Ag, and Sn-0.7Cu-0.05Ni, are used as case studies to demonstrate that (I) growth competition between primary dendrites and eutectic fronts during growth in undercooled melts is important in Pb-free solders and (II) a metastable eutectic containing NiSn4 forms in Sn-3.5Ag/Ni joints. Additionally, it is shown that the substrate (metallization) has a strong influence on the nucleation and growth of tin. We identify Co, Pd, and Pt substrates as having the potential to control solidification and microstructure formation. In the case of Pd and Pt substrates, βSn is shown to nucleate on the PtSn4 or PdSn4 intermetallic compound (IMC) reaction layer at relatively low undercooling of ~4 K, even for small solder ball diameters down to <200 μm.

  11. Microstructural Coarsening during Thermomechanical Fatigue and Annealing of Micro Flip-Chip Solder Joints

    Energy Technology Data Exchange (ETDEWEB)

    Barney, Monica Michele [Univ. of California, Berkeley, CA (United States)

    1998-12-01

    Microstructural evolution due to thermal effects was studied in micro solder joints (55 ± 5 μm). The composition of the Sn/Pb solder studied was found to be hypereutectic with a tin content of 65-70 wt%.This was determined by Energy Dispersive X-ray analysis and confirmed with quantitative stereology. The quantitative stereological value of the surface-to-volume ratio was used to characterize and compare the coarsening during thermal cycling from 0-160 C to the coarsening during annealing at 160 C. The initial coarsening of the annealed samples was more rapid than the cycled samples, but tapered off as time to the one-half as expected. Because the substrates to which the solder was bonded have different thermal expansion coefficients, the cycled samples experienced a mechanical strain with thermal cycling. The low-strain cycled samples had a 2.8% strain imposed on the solder and failed by 1,000 cycles, despite undergoing less coarsening than the annealed samples. The high-strain cycled samples experienced a 28% strain and failed between 25 and 250 cycles. No failures were observed in the annealed samples. Failure mechanisms and processing issues unique to small, fine pitch joints are also discussed.

  12. [Assessment of exposure to toxic metals released during soldering and grazing processes].

    Science.gov (United States)

    Matczak, Wanda

    2002-01-01

    The aim of the study was to assess toxic metal exposure in workers performing soldering and brazing operations. The study group included workers of three plants manufacturing electronic systems, household equipment and electric motors. Membrane filters were used to collect 50 air samples, including personal 8-h samples to assess average weighed concentration of soldering and brazing fumes and their elements, and to assay respirable dust and "background" or "area" samples. After testing by gravimetry, the filter with collected sample was mineralized with concentrated HCL/HNO3 and 10 ml sample solution in 32% HCL/4% HNO3 was prepared according to OSHA ID-206. Atomic absorption spectrometry was used to assess the contents of lead (Pb), tin (Sn), copper (Cu), zinc (Zn), antimony (Sb), silver (Ag) and manganese (Mn) in the sample solution. The quantitative analysis revealed that time-weighed average (TWA) of fume concentrations were: soldering fume Cu brazing fume Cu < 0.003-0.038 mg/m3, Zn < 0.003-0.025 mg/m3, Pb < 0.014-0.023 mg/m3, Ag < 0.014 mg/m3, Sn < 0.15 mg/m3, Mn < 0.07-0.12 mg/m3. The results show that on the day of measurements, working conditions at solderer/brazer workplaces were safe, i.e. relevant MAC values were not exceeded.

  13. Microstructures and fatigue life of SnAgCu solder joints bearing Nano-Al particles in QFP devices

    Science.gov (United States)

    Zhang, Liang; Fan, Xi-ying; Guo, Yong-huan; He, Cheng-wen

    2014-05-01

    Microstructures and fatigue life of SnAgCu and SnAgCu bearing nano-Al particles in QFP (Quad flat package) devices were investigated, respectively. Results show that the addition of nano-Al particles into SnAgCu solder can refine the microstructures of matrix microstructure. Moreover, the nano-Al particles present in the solder matrix, act as obstacles which can create a back stress, resisting the motion of dislocations. In QFP device, it is found that the addition of nano-Al particles can increase the fatigue life by 32% compared with the SnAgCu solder joints during thermal cycling loading.

  14. Mechanical Characterization of Lead-Free Sn-Ag-Cu Solder Joints by High-Temperature Nanoindentation

    OpenAIRE

    Lotfian, S.; Molina Aldareguía, Jon M.; Yazzie, K. E.; Llorca Martinez, Francisco Javier; Chawla, N

    2013-01-01

    The reliability of Pb-free solder joints is controlled by their microstructural constituents. Therefore, knowledge of the solder microconstituents’ mechanical properties as a function of temperature is required. Sn-Ag-Cu lead-free solder alloy contains three phases: a Sn-rich phase, and the intermetallic compounds (IMCs) Cu6Sn5 and Ag3Sn. Typically, the Sn-rich phase is surrounded by a eutectic mixture of β-Sn, Cu6Sn5, and Ag3Sn. In this paper, we report on the Young’s modulus and hardness of...

  15. Characterization and modeling of microstructural evolution of near-eutectic tin-silver-copper solder joints

    Science.gov (United States)

    Zbrzezny, Adam R.

    Near-eutectic Sn-Ag-Cu (SAC) solders are currently considered as major lead-free replacement candidates for Sn-Pb eutectic alloys in microelectronics applications. In this thesis, the microstructural thermal stability including recrystallization, grain growth behavior, Pb and Au contamination effects and interaction of the SAC solder with Cu and Ni substrates were investigated. The true eutectic composition of the Sn-Ag-Cu alloy was verified to be Sn3.5Ag0.9Cu wt.%, and the eutectic melting temperature was determined to be 217.4 +/- 0.8°C. The system was classified as belonging to faceting (Cu6Sn5)-faceting (Ag3Sn)-nonfaceting (Sn matrix) ternary eutectic. The most significant consequence of Pb contamination was the formation of a quaternary eutectic phase (Sn-Ag-Cu-Pb) with a melting point at 176°C. Similarly, the presence of gold in the SAC alloy led to a development of a new quaternary phase (Sn-Ag-Cu-Au) melting at 204°C. Prolonged aging of SAC-4 wt.% Au on nickel resulted in the deposition of a new, previously unreported, intermetallic (IMC) layer, ((Au1-xCUx)6Sn 5, 15 wt.% of Au) on top of the existing (Cu1-yNi y)6Sn5 layer. The interfacial products that formed during soldering to copper were Cu6Sn5 and Cu3Sn. Soldering to nickel resulted in the formation of one layer, (Cu1-yNiy) 6Sn5, which was different from the expected Ni3Sn 4 layer. A small copper content in the SAC solder (0.7 wt.%) was sufficient to promote this thermodynamic shift. Intermetallic growth on Cu during solid state aging was established to be bulk diffusion controlled. The IMC layers in the SAC system grew at a slower rate than in the Sn-Pb system. It was found that the reliability of SAC solder joints on copper was considerably better than on nickel due to copper enrichment during reflow and subsequent Cu6Sn5 intermetallic precipitation. Enhanced copper and silver diffusion followed by tin recrystallization and grain growth, cavity nucleation and subsequent micro-crack linkage formed

  16. Solid protein solder-doped biodegradable polymer membranes for laser-assisted tissue repair

    Science.gov (United States)

    Hodges, Diane E.; McNally-Heintzelman, Karen M.; Welch, Ashley J.

    2000-05-01

    Solid protein solder-doped polymer membranes have been developed for laser-assisted tissue repair. Biodegradable polymer films of controlled porosity were fabricated with poly(L-lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) using a solvent-casting and particulate-leaching technique. The films provided a porous scaffold that readily absorbed the traditional protein solder mix composed of bovine serum albumin (BSA) and indocyanine green (ICG) dye. In vitro investigations were conducted to assess the influence of various processing parameters on the strength of tissue repairs formed using the new membranes. These parameters included the PLGA copolymer and PLGA/PEG blend ratio, the salt particle size, the initial bovine serum albumin (BSA) weight fraction, and the laser irradiance used to denature the solder. Altering the PLGA copolymer ratio had little effect on repair strength, however, it influenced the membrane degradation rate. Repair strength increased with increased membrane pore size and BSA concentration. The addition of PEG during the film casting stage increased the flexibility of the membranes but not necessarily the repair strength. The repair strength increased with increasing irradiance from 12 W/cm2 to 15 W/cm2. The new solder-doped polymer membranes provide all of the benefits associated with solid protein solders including high repair strength and improved edge coaptation. In addition, the flexible and moldable nature of the new membranes offer the capability of tailoring the membranes to a wide range of tissue geometries, and consequently, improved clinical applicability of laser- assisted tissue repair.

  17. Effects of soldering and laser welding on bond strength of ceramic to metal.

    Science.gov (United States)

    Aladağ, Akin; Cömlekoğlu, M Erhan; Dündar, Mine; Güngör, M Ali; Artunç, Celal

    2011-01-01

    Welding or soldering of metal frameworks negatively affects the overall bond strength between the veneering ceramic and metal. The purpose of this study was to evaluate the effect of soldering and laser-welding procedures on the bond strength between ceramic and metal. Thirty Ni-based metal specimens (Wiron 99) (8 × 4 × 4 mm) were fabricated and divided into 3 groups; soldered (S), laser welded (L), and control (untreated cast alloy) (n=10). In S and L specimens, a notch (1 × 1.5 mm) was prepared longitudinally on the surface of each specimen and filled with compatible alloy (Wiron soldering rods and Wiroweld NC, respectively). Vickers hardness measurements were made after polishing the surfaces with a metallographic polishing kit. A veneering ceramic (VITA VMK 95) was vibrated, condensed in a mold, and fired on the metal frameworks. The specimens were sectioned in 2 axes to obtain nontrimmed bar specimens with a bonding area of approximately 1 mm². Forty bars per block were obtained. Each bar was subjected to microtensile bond strength (μTBS) testing with a crosshead speed of 1 mm/min. The μTBS data (MPa) were recorded, and SEM was used for failure analysis of the tested bars. The measurements were statistically analyzed using a 1-way ANOVA and Tamhane tests (α=.05). The mean differences in μTBS of veneering ceramic to soldered (10.4 ±2.4 MPa) and laser-welded (11.7 ±1.3 MPa) metal surfaces were not significantly different and were significantly lower than that of the cast alloy (25.4 ±3.6 MPa) (Plaser-welded groups (129 ±11 HV) (Plaser welding significantly decreased the μTBS of a veneering ceramic to a base metal alloy. Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  18. 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.

  19. Soldered joints—an essential component of demountable high temperature superconducting fusion magnets

    Science.gov (United States)

    Tsui, Yeekin; Surrey, Elizabeth; Hampshire, Damian

    2016-07-01

    Demountable superconducting magnet coils would offer significant benefits to commercial nuclear fusion power plants. Whether large pressed joints or large soldered joints provide the solution for demountable fusion magnets, a critical component or building block for both will be the many, smaller-scale joints that enable the supercurrent to leave the superconducting layer, cross the superconducting tape and pass into the solder that lies between the tape and the conductor that eventually provides one of the demountable surfaces. This paper considers the electrical and thermal properties of this essential component part of demountable high temperature superconducting (HTS) joints by considering the fabrication and properties of jointed HTSs consisting of a thin layer of solder (In52Sn48 or Pb38Sn62) sandwiched between two rare-earth-Ba2Cu3O7 (REBCO) second generation HTS coated conductors (CCs). The HTS joints are analysed using numerical modelling, critical current and resistivity measurements on the joints from 300 to 4.2 K in applied magnetic fields up to 12 T, as well as scanning electron microscopy studies. Our results show that the copper/silver layers significantly reduce the heating in the joints to less than a few hundred mK. When the REBCO alone is superconducting, the joint resistivity (R J) predominantly has two sources, the solder layer and an interfacial resistivity at the REBCO/silver interface (∼25 nΩ cm2) in the as-supplied CCs which together have a very weak magnetoresistance in fields up to 12 T. We achieved excellent reproducibility in the R J of the In52Sn48 soldered joints of better than 10% at temperatures below T c of the REBCO layer which can be compared to variations of more than two orders of magnitude in the literature. We also show that demountable joints in fusion energy magnets are viable and need only add a few percent to the total cryogenic cost for a fusion tokamak.

  20. 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.

  1. Science & Technology Review October 2005

    Energy Technology Data Exchange (ETDEWEB)

    Aufderheide III, M B

    2005-08-22

    This month's issue has the following articles: (1) Important Missions, Great Science, and Innovative Technology--Commentary by Cherry A. Murray; (2) NanoFoil{reg_sign} Solders with Less Heat--Soldering and brazing to join an array of materials are now Soldering and brazing to join an array of materials are now possible without furnaces, torches, or lead; (3) Detecting Radiation on the Move--An award-winning technology can detect even small amounts An award-winning technology can detect even small amounts of radioactive material in transit; (4) Identifying Airborne Pathogens in Time to Respond--A mass spectrometer identifies airborne spores in less than A mass spectrometer identifies airborne spores in less than a minute with no false positives; (5) Picture Perfect with VisIt--The Livermore-developed software tool VisIt helps scientists The Livermore-developed software tool VisIt helps scientists visualize and analyze large data sets; (6) Revealing the Mysteries of Water--Scientists are using Livermore's Thunder supercomputer and new algorithms to understand the phases of water; and (7) Lightweight Target Generates Bright, Energetic X Rays--Livermore scientists are producing aerogel targets for use in inertial Livermore scientists are producing aerogel targets for use in inertial confinement fusion experiments and radiation-effects testing.

  2. An ArsR/SmtB family member is involved in the regulation by arsenic of the arsenite oxidase operon in Thiomonas arsenitoxydans.

    Science.gov (United States)

    Moinier, Danielle; Slyemi, Djamila; Byrne, Deborah; Lignon, Sabrina; Lebrun, Régine; Talla, Emmanuel; Bonnefoy, Violaine

    2014-10-01

    The genetic organization of the aioBA operon, encoding the arsenite oxidase of the moderately acidophilic and facultative chemoautotrophic bacterium Thiomonas arsenitoxydans, is different from that of the aioBA operon in the other arsenite oxidizers, in that it encodes AioF, a metalloprotein belonging to the ArsR/SmtB family. AioF is stabilized by arsenite, arsenate, or antimonite but not molybdate. Arsenic is tightly attached to AioF, likely by cysteine residues. When loaded with arsenite or arsenate, AioF is able to bind specifically to the regulatory region of the aio operon at two distinct positions. In Thiomonas arsenitoxydans, the promoters of aioX and aioB are convergent, suggesting that transcriptional interference occurs. These results indicate that the regulation of the aioBA operon is more complex in Thiomonas arsenitoxydans than in the other aioBA containing arsenite oxidizers and that the arsenic binding protein AioF is involved in this regulation. On the basis of these data, a model to explain the tight control of aioBA expression by arsenic in Thiomonas arsenitoxydans is proposed.

  3. SnAg-alloy coating for connectors and soldering applications; Alliages SnAg pour revetements de connecteurs et brasage

    Energy Technology Data Exchange (ETDEWEB)

    Buresch, I. [Wieland-Werke AG, Ulm (Germany)

    2003-02-01

    The announced ban of lead in electronic products (WEEE-Waste Electrical and Electronic Equipment from 2006 onwards) is one chance to implement better alternatives. It is a challenge for researcher to develop one alternative which fulfills the different requirements for conditions in use for connectors and production like soldering. The system SnAgCu gives us.good opportunities for soldering applications and as a coating material for connectors. The tin-silver-copper alloy SnTOP meets the engine compartment requirements in automobiles in terms of temperature exposure while simultaneously provide low insertion forces using it as a functional coating on connectors combined with good solderability using it as a solder. (authors)

  4. THE EFFECT OF REFLOW ON WETTABILITY OF Sn 96.5 Ag 3 Cu 0.5 SOLDER

    Directory of Open Access Journals (Sweden)

    Zoltán Weltsch

    2012-12-01

    Full Text Available Surface conditions on Printed Circuit Board (PCB final finishes have an important impact on the wetting behavior with lead-free solder. The improvement of the 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 were 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 affecting the wetting properties is the amount of oxygen in the soldering atmosphere. Using the inert atmosphere is crucial in case of Pb-free solders, particularly after reflows.

  5. 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.

  6. 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...... cases, as the flux residue left on a printed circuit board assembly is a key factor compromising the corrosion reliability under humid conditions. This investigation focuses on the chemical degradation of three kinds of solder flux systems based on adipic, succinic, and glutaric acid as a function...... determination. Effect on corrosion reliability was investigated by exposing the test printed circuit board assemblies to humidity after pre-contaminating with pure acids and desired solder flux systems and measuring the charge transferred between electrodes under applied potential bias. Results showed...

  7. Preparation and soldering test for rapid solidification Sn-Ag-Cu solder alloy%快速凝固型Sn-Ag-Cu系钎料合金制备及钎焊工艺试验

    Institute of Scientific and Technical Information of China (English)

    李攀; 张鑫; 刘治军; 高广东; 熊毅

    2012-01-01

    采用单辊法制备了快速凝固型Sn2.5Ag0.7Cu钎料合金,在对其进行XRD检测、熔化特性测定和钎焊工艺试验后,对一定钎焊工艺条件下钎焊接头的力学性能和显微组织进行了测试分析,结果表明:所制备的钎料合金的熔化特性和钎焊接头力学性能满足要求,钎缝-母材界面上金属间化合物呈不均匀分布,且朝向钎焊缝中心生长.%Rapid solidification Sn2.5Ag0.7Cu solder alloy was prepared by using single-roller method, after XRD-test and testing the melting property and soldering procedure, the mechanical properties and microstructure of the joints under given soldering conditions were tested and analyzed. The results showed that the melting property of the solder alloy and mechanical properties of the joint were satisfactory. The IMC located at the solder-parent metal interface had an uneven distribution, and they grew toward the center of the solder seam.

  8. Electromigration and solid state aging of flip chip solder joints and analysis of tin whisker on lead-frame

    Science.gov (United States)

    Lee, Taekyeong

    Electromigration and solid state aging in flip chip joint, and whisker on lead frame of Pb-containing (eutectic SnPb) and Pb-free solders (SnAg 3.5, SnAg3.8Cu0.7, and SnCu0.7), have been studied systematically, using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDX), and synchrotron radiation. The high current density in flip chip joint drives the diffusion of atoms of eutectic SnPb and SnAgCu. A marker is used to measure the diffusion flux in a half cross-sectioned solder joint. SnAgCu shows higher resistance against electromigration than eutectic SnPb. In the half cross-sectioned solder joint, void growth is the dominant failure mechanism. However, the whole solder balls in the underfill show that the failure mechanism is a result from the dissolution of electroless Ni under bump metallization (UBM) of about 10 mum thickness. The growth rate between intermetallic compounds in molten and solid solders differed by four orders of magnitude. In liquid solder, the growth rate is about 1 mum/min; the growth rate in solid solder is only about 10 -4 mum/min. The difference is not resulting from factors of thermodynamics, which is the change of Gibbs free energy before and after intermetallic compound formation, but from kinetic factors, which is the rate of change of Gibbs free energy. Even though the difference in growth rate between eutectic SnPb and Pb-free solders during solid state aging was found, the reason behind such difference shown is unclear. The orientation and stress levels of whiskers are measured by white X-ray of synchrotron radiation. The growth direction is nearly parallel to one of the principal axes of tin. The compressive stress level is quite low because the residual stress is relaxed by the whisker growth.

  9. Study of intermetallic compound layer formation, growth and evaluation of shear strength of lead-free solder joints

    OpenAIRE

    Bernasko, Peter Kojo

    2012-01-01

    Solder joints play a very important role in electronic products as the integrity of electronics packaging and assembly rests on the quality of these connections. The increasing demands for higher performance, lower cost, and miniaturisation in hand-held and consumer electronic products have led to the use of dense interconnections. This miniaturization trend means that solder joint reliability remains an important challenge with surface mount electronics assembly, especially those used in hos...

  10. Dissolution and Interfacial Reactions of (Cu,Ni)6Sn5 Intermetallic Compound in Molten Sn-Cu-Ni Solders

    Science.gov (United States)

    Wang, Chao-hong; Lai, Wei-han; Chen, Sinn-wen

    2014-01-01

    (Cu,Ni)6Sn5 is an important intermetallic compound (IMC) in lead-free Sn-Ag-Cu solder joints on Ni substrate. The formation, growth, and microstructural evolution of (Cu,Ni)6Sn5 are closely correlated with the concentrations of Cu and Ni in the solder. This study reports the interfacial behaviors of (Cu,Ni)6Sn5 IMC (Sn-31 at.%Cu-24 at.%Ni) with various Sn-Cu, Sn-Ni, and Sn-Cu-Ni solders at 250°C. The (Cu,Ni)6Sn5 substrate remained intact for Sn-0.7 wt.%Cu solder. When the Cu concentration was decreased to 0.3 wt.%, (Cu,Ni)6Sn5 significantly dissolved into the molten solder. Moreover, (Cu,Ni)6Sn5 dissolution and (Ni,Cu)3Sn4 formation occurred simultaneously for the Sn-0.1 wt.%Ni solder. In Sn-0.5 wt.%Cu-0.2 wt.%Ni solder, many tiny (Cu,Ni)6Sn5 particulates were formed and dispersed in the solder matrix, while in Sn-0.3 wt.%Cu-0.2 wt.%Ni a lot of (Ni,Cu)3Sn4 grains were produced. Based on the local equilibrium hypothesis, these results are further discussed based on the liquid-(Cu, Ni)6Sn5-(Ni,Cu)3Sn4 tie-triangle, and the liquid apex is suggested to be very close to Sn-0.4 wt.%Cu-0.2 wt.%Ni.

  11. Enhancement on wettability and intermetallic compound formation with an addition of Al on Sn-0.7Cu lead-free solder fabricated via powder metallurgy method

    Science.gov (United States)

    Adli, Nisrin; Razak, Nurul Razliana Abdul; Saud, Norainiza

    2016-07-01

    Due to the toxicity of lead (Pb), the exploration of another possibility for lead-free solder is necessary. Nowadays, SnCu alloys are being established as one of the lead-free solder alternatives. In this study, Sn-0.7Cu lead-free solder with an addition of 1wt% and 5wt% Al were investigated by using powder metallurgy method. The effect of Al addition on the wettability and intermetallic compound thickness (IMC) of Sn-0.7Cu-Al lead-free solder were appraised. Results showed that Al having a high potential to enhance Sn-0.7Cu lead-free solder due to its good wetting and reduction of IMC thickness. The contact angle and IMC of the Sn-0.7Cu-Al lead-free solder were decreased by 14.32% and 40% as the Al content increased from 1 wt% to 5 wt%.

  12. Wetting Behavior and Interfacial Reactions in (Sn-9Zn)-2Cu/Ni Joints during Soldering and Isothermal Aging

    Institute of Scientific and Technical Information of China (English)

    Ning Zhao; Haitao Ma; Haiping Xie; Lai Wang

    2009-01-01

    The wetting property of (Sn-9Zn)-2Cu (wt pct) on Ni substrate and the evolution of interfacial microstructure in (Sn-9Zn)-2Cu/Ni joints during soldering as well as isothermal aging were studied.The wetting ability of eutectic Sn-9Zn solder on Ni substrate was markedly improved by adding 2 wt pct Cu into this solder alloy.Plate-like Cu5Zn8 intermetallic compounds (IMCs) were detected in (Sn-9Zn)-2Cu solder matrix.A continuous Ni5Zn21 IMC layer was formed at (Sn-9Zn)-2Cu/Ni interface after soldering.This IMC layer kept its type and integrality even after aging at 170℃ for up to 1000 h.At the early aging stage (before 500 h), the IMC layer grew fast and its thickness followed a linear relationship with the square root of aging time.Thereafter,however, the thickness increased very slowly with longer aging time.When the joints were aged for 1000 h,a new IMC phase, (Cu,Ni)5Zn8, was found in the matrix near the interface.The formation of (Cu,Ni)5Zn8phase can be attributed to the diffusion of Ni atoms into the solder matrix from the substrate.

  13. 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.

  14. Characteristics of intermetallics and micromechanical properties during thermal ageing of Sn-Ag-Cu flip-chip solder interconnects

    Energy Technology Data Exchange (ETDEWEB)

    Li Dezhi [Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom); Liu Changqing [Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom)]. E-mail: c.liu@lboro.ac.uk; Conway, Paul P. [Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom)

    2005-01-25

    Sn-3.8 wt.% Ag-0.7 wt.% Cu solder was applied to Al-1 wt.% Cu bond pads with an electroless nickel (Ni-P) interlayer as an under bump metallisation (UBM). The microstructure and micromechanical properties were studied after ageing at 80 deg. C and 150 deg. C. Two types of intermetallic compounds (IMCs) were identified by electron back-scattered diffraction (EBSD), these being a (Cu, Ni){sub 6}Sn{sub 5} formed at the solder-UBM interface and Ag{sub 3}Sn in the bulk solder. The (Cu, Ni){sub 6}Sn{sub 5} layer grew very slowly during the ageing process, with no Kirkendall voids found by scanning electron microscopy (SEM) after ageing at 80 deg. C. Nano-indentation was used to analyse the mechanical properties of different phases in the solder. Both (Cu, Ni){sub 6}Sn{sub 5} and Ag{sub 3}Sn were harder and more brittle than the {beta}-Sn matrix of the Sn-Ag-Cu alloy. The branch-like morphology of the Ag{sub 3}Sn IMC, especially at the solder-UBM interface, could ultimately be detrimental to the mechanical integrity of the solder when assembled in flip-chip joints.

  15. Characterizing the Mechanical Properties of Actual SAC105, SAC305, and SAC405 Solder Joints by Digital Image Correlation

    Science.gov (United States)

    Nguyen, T. T.; Yu, D.; Park, S. B.

    2011-06-01

    This paper presents the characterization of the mechanical properties of three lead-free solder alloys 95.5Sn-4.0Ag-0.5Cu (SAC405), 96.5Sn-3.0Ag-0.5Cu (SAC305), and 98.5Sn-1.0Ag-0.5Cu (SAC105) at the solder joint scale. Several actual ChipArray ® ball grid array (CABGA) packages were cross-sectioned, polished, and used as test vehicles. Compressive tests were performed using a nanocharacterization system over the temperature range of 25°C to 105°C. Images of the cross-sectioned solder joints were recorded by microscope during the tests. The recorded images were then processed by using a digital image correlation (DIC) program to calculate the displacement and strain fields on the solder joints. Finite-element method (FEM) modeling was used to extract the Poisson's ratio, Young's modulus, and coefficient of thermal expansion (CTE) of the solder alloys over the temperature range. The methodology developed in this paper enables characterization of the mechanical properties of the actual solder joints at low strain range with high accuracy.

  16. Influence of Dopant on Growth of Intermetallic Layers in Sn-Ag-Cu Solder Joints

    Science.gov (United States)

    Li, G. Y.; Bi, X. D.; Chen, Q.; Shi, X. Q.

    2011-02-01

    The interfacial interaction between Cu substrates and Sn-3.5Ag-0.7Cu- xSb ( x = 0, 0.2, 0.5, 0.8, 1.0, 1.5, and 2.0) solder alloys has been investigated under different isothermal aging temperatures of 100°C, 150°C, and 190°C. Scanning electron microscopy (SEM) was used to measure the thickness of the intermetallic compound (IMC) layer and observe the microstructural evolution of the solder joints. The IMC phases were identified by energy-dispersive x-ray spectroscopy (EDX) and x-ray diffractometry (XRD). The growth of both the Cu6Sn5 and Cu3Sn IMC layers at the interface between the Cu substrate and the solder fits a power-law relationship with the exponent ranging from 0.42 to 0.83, which suggests that the IMC growth is primarily controlled by diffusion but may also be influenced by interface reactions. The activation energies and interdiffusion coefficients of the IMC formation of seven solder alloys were determined. The addition of Sb has a strong influence on the growth of the Cu6Sn5 layer, but very little influence on the formation of the Cu3Sn IMC phase. The thickness of the Cu3Sn layer rapidly increases with aging time and temperature, whereas the thickness of the Cu6Sn5 layer increases slowly. This is probably due to the formation of Cu3Sn at the interface between two IMC phases, which occurs with consumption of Cu6Sn5. Adding antimony to Sn-3.5Ag-0.7Cu solder can evidently increase the activation energy of Cu6Sn5 IMC formation, reduce the atomic diffusion rate, and thus inhibit excessive growth of Cu6Sn5 IMCs. This study suggests that grain boundary pinning is one of the most important mechanisms for inhibiting the growth of Cu6Sn5 IMCs in such solder joints when Sb is added.

  17. Technology handbook of vacuum physics

    CERN Document Server

    Beck, A H

    2013-01-01

    Handbook of Vacuum Physics, Volume 3: Technology is part of a series of publications that presents articles featuring the whole spectrum of vacuum physics. This particular volume presents materials that deal with technology concerns in vacuum mechanics. The first material talks about the utilization of ceramic materials in the construction of vacuum devices. The next paper details the application of vacuum physics in soldering and brazing process. The last article deals with the utilization of vacuum technology in high frequency heating. The book will be of great use to professionals involved

  18. Reaction Between Thin Gold Wires and Pb-Sn-In Solder (37.5%, 37.5%, 25%), Part A: The Radial Reaction Inside The Solder Mounds, Its Linear Reaction Model, Statistical Variation of Reaction Rate, and Induced Structural Changes In The Solder Mounds.

    Energy Technology Data Exchange (ETDEWEB)

    Siekhaus, W J

    2011-01-19

    Thermodynamics favors the reaction between indium and gold, since the heat of formation of AuIn{sub 2} is 6 kcal/mole, substantially larger than the heat of formation of any other possible reaction product. Thermodynamic equilibrium between gold and the elements in the solder mound is reached only when ALL gold is converted to AuIn{sub 2}. There are two aspects to this conversion: (A) the reaction WITHIN the solder mound (called here 'radial reaction') and (B) the reaction OUTSIDE the solder mound (called here 'axial reaction') and the transition from (A) to (B). The reaction between thin gold detonator wires and the In/Pb/Sn solder mound in older detonators has been looked at repeatedly. There are, in addition, two studies which look at the reaction between indium and gold in planar geometry. All data are shown in tables I to V. It is the objective of this section dealing with aspect (A), to combine all of these results into a reaction model and to use this reaction model to reliably and conservatively predict the gold-solder reaction rate of soldered gold bridge-wires as a function of storage temperature and time.

  19. 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

    2017-03-01

    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.

  20. A Study of Temperature, Microstructure and Hardness Properties of Sn-3.8Ag-0.7Cu (SAC Solder Alloy

    Directory of Open Access Journals (Sweden)

    Singh Amares

    2015-01-01

    Full Text Available Solder alloys are one of the most crucial aspect linking the electrical components to the printed circuit board PCB substrate. Thus, producing a good solder is a must to say in electronic industries. Among major functions of solder alloys are to provide beneficial properties in melting, microstructure and mechanical strand. In this aspect, the Sn-3.8Ag-0.7Cu (SAC solder alloys are recommended as potential candidate to assure these benefits. In this study, the solder possesses melting temperature of, TM=227°C which is below the desired soldering temperature, TM=250°C. Besides, this SAC solder produces well-defined microstructures with Sn-matrix and eutectic phase consisting Cu6Sn5 and Ag3Sn displayed from SEM image, contributes in harvesting good mechanical properties. The SAC solder also provides a high hardness value with an average of 14.4Hv for Vickers hardness. All these results seem to satisfy the need of a viable solder alloy.

  1. 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.

  2. An Organic Metal/Silver Nanoparticle Finish on Copper for Efficient Passivation and Solderability Preservation

    Directory of Open Access Journals (Sweden)

    Wessling Bernhard

    2007-01-01

    Full Text Available AbstractFor the first time, a complex formed by polyaniline (in its organic metal form and silver has been deposited on copper in nanoparticulate form. When depositing on Cu pads of printed circuit boards it efficiently protects against oxidation and preserves its solderability. The deposited layer has a thickness of only nominally 50 nm, containing the Organic Metal (conductive polymer, polyaniline, and silver. With >90% (by volume, polyaniline (PAni is the major component of the deposited layer, Ag is present equivalent to a 4 nm thickness. The Pani–Ag complex is deposited on Cu in form of about 100 nm small particles. Morphology, electrochemical characteristics, anti-oxidation and solderability results are reported.

  3. 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.

  4. Relative effect of solder flux chemistry on the humidity related failures in electronics

    DEFF Research Database (Denmark)

    Verdingovas, Vadimas; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-01-01

    was studied by quartz crystal microbalance, while corrosive effects were studied by leakage current and impedance measurements on standard test boards. The measurements were performed as a function of relative humidity (RH) in the range from 60 to ~99 per cent at 25°C. The corrosiveness of solder flux systems...... of printed circuit boards under humid conditions. Originality/value - The classification of solder flux systems according to IPC J-STD-004 standard does not specify the WOAs in the flux; however, ranking of the flux systems based on the hygroscopic property of activators would be useful information when...... selecting no-clean flux systems for electronics with applications in humid conditions....

  5. Thermal compression chip interconnection using organic solderability preservative etched substrate by plasma processing.

    Science.gov (United States)

    Cho, Sung-Won; Choi, JoonYoung; Chung, Chin-Wook

    2014-12-01

    The solderability of copper organic solderbility preservative (CuOSP) finished substrate was enhanced by the plasma etching. To improve the solderability of TC interconnection with the CuOSP finished substrate, the plasma etching process is used. An Oxygen-Hydrogen plasma treatment process is performed to remove OSP material. To prevent the oxidation by oxygen plasma treatment, hydrogen reducing process is also performed before TC interconnection process. The thickness of OSP material after plasma etching is measured by optical reflection method and the component analysis by Auger Electron Spectroscopy is performed. From the lowered thickness, the bonding force of TC interconnection after OSP etching process is lowered. Also the electrical open/short test was performed after assembling the completed semiconductor packaging. The improved yield due to the plasma etching process is achieved.

  6. Failure Modes of Lead Free Solder Bumps Formed by Induction Spontaneous Heating Reflow

    Institute of Scientific and Technical Information of China (English)

    Mingyu LI; Hongbo XU; Jongmyung KIM; Hongbae KIM

    2007-01-01

    The shear failure modes and respective failure mechanism of Sn3.5Ag and Sn3.0Ag0.5Cu lead-free solder bumping on Au/Ni/Cu metallization formed by induction spontaneous heating reflow process have been investigated through the shear test after aging at 120℃ for 0, 1, 4, 9 and 16 d. Different typical shear failure behaviors have been found in the loading curves (shear force vs displacement). From the results of interfacial morphology analysis of the fracture surfaces and cross-sections, two main typical failure modes have been identified. The probabilities of the failure modes occurrence are inconsistent when the joints were aged for different times. The evolution of the brittle Ni3Sn4 and Cu-Ni-Au-Sn layers and the grains coarsening of the solder bulk are the basic reasons for the change of shear failure modes.

  7. Contributions of Stress and Oxidation on the Formation of Whiskers in Pb-free Solders

    Science.gov (United States)

    2016-01-29

    Oxidation on the Formation of Whiskers in Pb‐free Solders,” WP-1754 15. SUBJECT TERMS Tin Whiskers, Residual Stress, Environmental Degradation 16...copper oxide and then rinsed using ultrapure water immediately before electroplating. Copper substrates were electroplated with pure tin films to a...thickness of 5 μm using a commercial Sn plating solution and a pure tin anode. Electroplating was performed at a constant current density of 11 mA

  8. 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

  9. Sputtered Ni-Zn under bump metallurgy (UBM) for Sn-Ag-Cu solders

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Jin; Kim, Young Min [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Kim, Young-Ho, E-mail: kimyh@hanyang.ac.kr [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Ni-Zn UBM can effectively suppress the growth of IMCs and the consumption of UBM. Black-Right-Pointing-Pointer The growth of (Ni, Cu){sub 3}Sn{sub 4} was retarded at the SAC305/Ni-Zn interface after aging. Black-Right-Pointing-Pointer Only a single (Cu, Ni){sub 6}Sn{sub 5} formed at the SAC107/Ni-Zn interface after aging. Black-Right-Pointing-Pointer Segregated Zn atoms on IMC layers retarded the interdiffusion of Cu, Ni, and Sn. Black-Right-Pointing-Pointer Sputtered Ni-Zn UBM is promising for Pb-free solder flip chip applications. - Abstract: We developed a new sputtered under bump metallurgy (UBM) based on Ni-20wt% Zn thin films for Pb-free solders. This study focuses on the interfacial reactions between two Pb-free solders (Sn3.0Ag0.5Cu and Sn1.0Ag0.7Cu) and a Ni-Zn alloy UBM. By adding Zn to Ni UBM, Zn is incorporated into intermetallic compounds (IMCs) to form a quaternary Cu-Ni-Zn-Sn phase at the solder/Ni-Zn interface after reflow and subsequent isothermal aging. The Ni-Zn UBM sufficiently reduces the interfacial reaction and IMCs formation rates as well as UBM consumption rates compared to a Ni UBM. In particular, the formation of (Ni, Cu){sub 3}Sn{sub 4} IMC was significantly retarded by adding Zn into UBM.

  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...

  11. 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

  12. Strength of MWCNT-Reinforced 70Sn-30Bi Solder Alloys

    Science.gov (United States)

    Billah, Md Muktadir; Chen, Quanfang

    2016-01-01

    In this study, the effect of Cu-coated multi-walled carbon nanotubes (MWCNTs) on the tensile strength of 70Sn-30Bi solder alloy has been investigated. Copper was first deposited onto metal-activated MWCNTs by an electroless process and confirmed with a scanning electron microscope and energy dispersive spectroscopy. Sn-Bi alloy solder was reinforced with Cu-coated MWCNTs with additions of 0.5 wt.%, 1 wt.%, 2 wt.%, and 3 wt.%, respectively. 70Sn-30Bi solder was produced by melting pure tin and bismuth in an inert gas atmosphere. Cu-coated MWCNTs were then added into the metal matrix by cold rolling, followed by hot pressing to disperse the carbon nanotubes (CNTs) in the matrix. Tensile tests were conducted on an mechanical testing and simulation (MTS) tester. The tensile strength was found to be proportional to the addition of Cu/MWCNTs, and about 47.6% increase in tensile strength over the pure alloy has been obtained for an addition of 3 wt.% Cu/MWCNTs. The Cu coating may enhance CNT dispersion to prevent tangling.

  13. 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.

  14. TEM observation of interfaces in a solder joint in a semiconductor device

    Directory of Open Access Journals (Sweden)

    Hirohisa Matsuki, Hiroshi Ibuka and Hiroyasu Saka

    2002-01-01

    Full Text Available Microstructure of a joint between a Pb–Sn eutectic solder and an electroless Ni–8 mass% P has been examined using transmission electron microscopy. Four layers, i.e. Ni3Sn4, Ni48Sn52, Ni2SnP and Ni–20 mass% P, are formed between the solder and the electroless Ni–8 mass% P. Among them, Ni48Sn52 and Ni2SnP were found for the first time in a solder joint. Spherical voids are formed at the interface between Ni48Sn52 and Ni2SnP, and columnar voids are formed at the interface between Ni2SnP and Ni–20 mass% P. From the analysis of the migration of the respective interfaces observed during in situ heating experiments, it is concluded that these voids are Kirkendall voids formed due to the difference in diffusivity of Ni across the interfaces. Fracture takes place at either of those interfaces during a dropping test.

  15. The Influence of PV Module Materials and Design on Solder Joint Thermal Fatigue Durability

    Energy Technology Data Exchange (ETDEWEB)

    Bosco, Nick; Silverman, Timothy J.; Kurtz, Sarah

    2016-11-01

    Finite element model (FEM) simulations have been performed to elucidate the effect of flat plate photovoltaic (PV) module materials and design on PbSn eutectic solder joint thermal fatigue durability. The statistical method of Latin Hypercube sampling was employed to investigate the sensitivity of simulated damage to each input variable. Variables of laminate material properties and their thicknesses were investigated. Using analysis of variance, we determined that the rate of solder fatigue was most sensitive to solder layer thickness, with copper ribbon and silicon thickness being the next two most sensitive variables. By simulating both accelerated thermal cycles (ATCs) and PV cell temperature histories through two characteristic days of service, we determined that the acceleration factor between the ATC and outdoor service was independent of the variables sampled in this study. This result implies that an ATC test will represent a similar time of outdoor exposure for a wide range of module designs. This is an encouraging result for the standard ATC that must be universally applied across all modules.

  16. Development of Stable, Low Resistance Solder Joints for a Space-Flight HTS Lead Assemblies

    Science.gov (United States)

    Canavan, Edgar R.; Chiao, Meng; Panashchenko, Lyudmyla; Sampson, Michael

    2017-01-01

    The solder joints in spaceflight high temperature superconductor (HTS) lead assemblies for certain astrophysics missions have strict constraints on size and power dissipation. In addition, the joints must tolerate years of storage at room temperature, many thermal cycles, and several vibration tests between their manufacture and their final operation on orbit. As reported previously, solder joints between REBCO coated conductors and normal metal traces for the Astro-H mission showed low temperature joint resistance that grew approximately as log time over the course of months. Although the assemblies worked without issue in orbit, for the upcoming X-ray Astrophysics Recovery Mission we are attempting to improve our solder process to give lower, more stable, and more consistent joint resistance. We produce numerous sample joints and measure time- and thermal cycle-dependent resistance, and characterize the joints using x-ray and other analysis tools. For a subset of the joints, we use SEMEDS to try to understand the physical and chemical processes that effect joint behavior.

  17. Thermo-mechanical fatigue reliability optimization of PBGA solder joints based on ANN-PSO

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ji-cheng; XIAO Xiao-qing; EN Yun-fei; CHEN Ni; WANG Xiang-zhong

    2008-01-01

    Based on a method combined artificial neural network (ANN) with particle swarm optimization (PSO) algorithm, the thermo-mechanical fatigue reliability of plastic ball grid array (PBGA) solder joints was studied. The simulation experiments of accelerated thermal cycling test were performed by ANSYS software. Based on orthogonal array experiments, a back-propagation artificial neural network (BPNN) was used to establish the nonlinear multivariate relationship between thermo-mechanical fatigue reliability and control factors. Then, PSO was applied to obtaining the optimal levels of control factors by using the output of BPNN as the affinity measure. The results show that the control factors, such as print circuit board (PCB) size, PCB thickness, substrate size,substrate thickness, PCB coefficient of thermal expansion (CTE), substrate CTE, silicon die CTE, and solder joint CTE, have a great influence on thermo-mechanical fatigue reliability of PBGA solder joints. The ratio of signal to noise of ANN-PSO method is 51.77dB and its error is 33.3% less than that of Taguchi method. Moreover, the running time of ANN-PSO method is only 2% of that of the BPNN. These conclusions are verified by the confirmative experiments.

  18. 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...

  19. 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...

  20. Uniaxial tensile and shear deformation tests of gold–tin eutectic solder film

    Directory of Open Access Journals (Sweden)

    Takahiro Namazu, Hideki Takemoto, Hiroshi Fujita and Shozo Inoue

    2007-01-01

    Full Text Available This paper describes a novel experimental technique for measuring mechanical properties of gold-tin (Au–Sn eutectic solder film used for soldering package in microelectromechanical systems (MEMS. Dual-source DC magnetron sputtering was employed to deposit Au-20 weight % (wt% Sn film. The tensile test with in situ X-ray diffraction (XRD measurement evaluates the Young's modulus and Poisson's ratio at intermediate temperatures. The Young's modulus and Poisson's ratio at room temperature were found to be 51.3 GPa and 0.288, lower than bulk values. The Young's modulus decreased with increasing temperature, whereas the Poisson's ratio did not depend on temperature. The XRD tensile test also showed creep deformation behavior of Au–Sn film. We have developed a shear deformation test technique, which is performed by using Au–Sn film sandwiched by two single crystal silicon (Si cantilever structures, to characterize the shear properties of the film. The shear moduli obtained from the shear deformation tests ranged from 11.5 to 13.3 GPa, about 38% lower than those from the XRD tensile tests. The measured shear strength from 12 to 17 MPa exhibited a temperature dependency. Information about the tensile and shear characteristics would likely to be of great use in designing Au–Sn soldering packages for MEMS.