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1
Чуйко М.М. and Завальський В. "THE CONTACT ANGLE CONTROL OF THE SOLDER FOR IMPROVING THE SOLDERING QUALITY." Перспективні технології та прилади, no. 17 (January 27, 2021): 161–66. http://dx.doi.org/10.36910/6775-2313-5352-2020-17-24.
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High quality of the soldering process can be achieved with the right choice of the necessary soldering materials. Since wetting determines the further nature of the connection between the solder and the main soldering material, the contact angle measurement is the basis for quality control of soldering materials, provided that the basic requirements of the technological process. The determination of the contact angle value is carried out by the indirect method of the sessile drop, by measuring the basic parameters of the drop using infrared transducer. A smaller value of the contact angle corresponds to a better interaction of materials, and hence a better electrical contact
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Chen, Zhihua, Cheng He, Ying Zheng, Xiaolong Shi, and Tao Song. "A Novel Thermodynamic Model and Temperature Control Method of Laser Soldering Systems." Mathematical Problems in Engineering 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/509031.
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Laser technology is vital in production of precision electronic components and has been widely used in modern industry. In laser soldering systems, accurate temperature control remains a challenging problem, since the temperature is highly sensitive to laser power and thermodynamic parameters of solder joints. In this paper, a good solution is proposed to solve the problem by controlling the temperature based on a novel thermodynamic model. In the model, many of the major factors are taken into account, such as laser energy, flux influence, and solder joints with different parameters. Aimed at the thermodynamic process and the influence of solder fluxes, a mixed mode control method is used to track the designed target temperature curve; this method can produce a solder joint with good quality. As a result, a model-based feed-forward and proportional, integral, and derivative (PID) mixed control method is developed. In practice, the proposed method is verified to have a wider product capability and production size; and a rate of good products of 99.94% is achieved with consuming approximately half of the energy comparing with manual soldering and constant laser power soldering.
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Alaya, Mohamed Amine, Balázs Illés, David Bušek, and Attila Géczy. "Validation of Heat-Level Vapor Phase Soldering Process and Workspace Leakage Detection with Applied Pressure Sensors." Applied Sciences 11, no. 4 (February 16, 2021): 1755. http://dx.doi.org/10.3390/app11041755.
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Electronic manufacturing principles are continuously developing, further improving assembly quality and productivity. There is a continuous need to apply novel and improved methods of process monitoring to provide accurate measurement and control during assembling. In this paper, a new principle for monitoring filmwise condensation-based heat-level—vapour phase soldering (HL-VPS) is presented to improve the process control. The experiment is based on thermocouple sensors in fusion with a sensitive gauge type pressure sensor. The aim is to precisely identify the steps of condensation-based reflow heat transfer process with commercially available components and the mindset of possible retrofitting in the generally used HL-VPS soldering ovens. It was found that the gauge sensor can follow the state of the workspace more precisely as the thermocouples, by monitoring the hydrostatic state of the vapour. The pressure (time) function gives information about the build-up of the vapour column, highlighting four characteristic steps (phases) of the process, meaning: immersion of the sample to be soldered, condensation-based heat transfer, solder-break, and cooling. Combined application with thermocouples enables more precise control, improving soldering quality and can reduce idle time of the oven. In addition, it was showed that the gauge type sensors could highlight any failure in the oven sealing by a sensor signal threshold detection. The original concept of workspace identification also fits the present and future industry 4.0 directives.
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Livovsky, Lubomir, and Alena Pietrikova. "Real-time profiling of reflow process in VPS chamber." Soldering & Surface Mount Technology 29, no. 1 (February 6, 2017): 42–48. http://dx.doi.org/10.1108/ssmt-10-2016-0026.
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Purpose This paper aims to present a new method of real-time monitoring of thermal profiles applied in vapour phase soldering (VPS) reflow processes. The thermal profile setting is a significant variable that affects the quality of joints. The method allows rapid achievement of a required thermal profile based on software control that brings new efficiency to the reflow process and enhanced joint quality, especially for power electronics. Design/methodology/approach A real-time monitoring system based on computerized heat control was realized in a newly developed laboratory VPS chamber using a proportional integral derivation controller within the soldering process. The principle lies in the strictly accurate monitoring of the real defined reflow profile as a reference. Findings Very accurate maintenance of the required reflow profile temperature was achieved with high accuracy (± 2°C). The new method of monitoring and control of the reflow real-time profiling was verified at various maximal reflow temperatures (230°C, 240°C and 260°C). The method is feasible for reflowing three-dimensional (3D) power modules that use various types of solders. The real-time monitoring system based on computerised heat control helped to achieve various heights of vapour zone. Originality/value The paper describes construction of a newly developed laboratory-scale VPS chamber, including novel real-time profiling of the reflow process based on intelligent continuously measured temperatures at various horizontal positions. Real-time profiling in the laboratory VPS chamber allowed reflow soldering on 3D power modules (of greater dimensions) by applying various flux-less solder materials.
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Пискарёв, Павел, Pavel Piskaryov, Александр Герваш, Alexandr Gervash, Андрей Огурский, Andrey Ogursky, Игорь Мазуль, and Igor Mazul. "Preparation to program carrying out of technology qualification of beryllium encasement vacuum induction soldering for components of ITER reactor." Science intensive technologies in mechanical engineering 2018, no. 8 (July 14, 2018): 33–41. http://dx.doi.org/10.30987/article_5b5364029d3393.57902132.
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A process of rapid vacuum induction soldering of the beryllium encasement of inner-chamber components for a thermonuclear reactor is considered. The soldering technological peculiarities, methods of control and tests of soldered joints are analyzed. Basic reasons in the defect formation and corresponding solutions used to increase joint quality are considered.
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Gao, Guilian, Hong Sheng, Sangil Lee, Bong-Sub Lee, Scott McGrath, Liang Wang, Charles Woychik, et al. "Development of 2.5D and 3D IC Fabrication and Assembly Technologies." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2015, DPC (January 1, 2015): 000075–108. http://dx.doi.org/10.4071/2015dpc-ta11.
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2.5D/3D IC assembly is where the traditional foundry and assembly house model breaks down. The greatly reduced feature sizes of microbumps in combination with very large, thin interposers and ICs present many challenges for assembly. With densely integrated packages and stacked thin dies, warpage at various steps of assembly process can lead to die crack, weak or open interconnection, and delamination. Microbump die with copper pillar and solder cap lacks the flexibility of conventional BGA solder balls in warpage compensation. Low temperature dielectric materials for interposer backside passivation lack chemical, thermal stability and mechanical strength compared to similar materials cured at higher temperatures. Ultra- low stand-off between dies creates new challenge for flux residue removal and underfill processing, adhesion and reliability. In this paper, we present learning and results from building two Invensas 2.5D interposer test vehicles with rectangular (19mmx27mm) and square (24mmx24 mm) silicon interposers. Since the industry is still debating where the MEOL processes will take place, these two test vehicles use both assembly centric and fab centric flows. We conducted comprehensive material and process compatibility studies to meet our goal of process capability and product reliability. We explored three different interposer fabrication/ assembly flows that includes copper-to-copper bonding as well as solder capped copper pillar microbumps for microbump die to interposer connection. We optimized the interposer fabrication process to improve interposer quality and warpage. We instituted 100% bump inspection and tight control on microbump die quality and co-planarity to improve assembly yield. We developed robust soldering and cleaning processes to achieve high soldering process yield. We evaluated several methods of flux clean and developed a procedure to achieve optimal flux residue removal without causing mechanical damage to solder joints. We explored vacuum and pressure curing process for underfill and adopted advance underfill cure technology to eliminate voids in underfill. The impact of these factors on assembly yield and reliability will be presented.
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Straubinger, Daniel, István Bozsóki, David Bušek, Balázs Illés, and Attila Géczy. "Modelling of temperature distribution along PCB thickness in different substrates during reflow." Circuit World 46, no. 2 (December 21, 2019): 85–92. http://dx.doi.org/10.1108/cw-07-2019-0074.
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Purpose In this paper, analytical modelling of heat distribution along the thickness of different printed circuit board (PCB) substrates is presented according to the 1 D heat transient conduction problem. This paper aims to reveal differences between the substrates and the geometry configurations and elaborate on further application of explicit modelling. Design/methodology/approach Different substrates were considered: classic FR4 and polyimide, ceramics (BeO, Al2O3) and novel biodegradables (polylactic-acid [PLA] and cellulose acetate [CA]). The board thicknesses were given in 0.25 mm steps. Results are calculated for heat transfer coefficients of convection and vapour phase (condensation) soldering. Even heat transfer is assumed on both PCB sides. Findings It was found that temperature distributions along PCB thicknesses are mostly negligible from solder joint formation aspects, and most of the materials can be used in explicit reflow profile modelling. However PLA shows significant temperature differences, pointing to possible modelling imprecisions. It was also shown, that while the difference between midplane and surface temperatures mainly depend on thermal diffusivity, the time to reach solder alloy melting point on the surface depends on volumetric heat capacity. Originality/value Results validate the applicability of explicit heat transfer modelling of PCBs during reflow for different heat transfer methods. The results can be incorporated into more complex simulations and profile predicting algorithms for industrial ovens controlled in the wake of Industry 4.0 directives for better temperature control and ultimately higher soldering quality.
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Arab, Mohammad Reza, and Mohammad Hossein Heidari. "Histological Study of the Toxic Effects of Solder Fumes on Spermatogenesis in Rats." Applied Mechanics and Materials 319 (May 2013): 115–20. http://dx.doi.org/10.4028/www.scientific.net/amm.319.115.
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Objective: Toxic fumes generated during the soldering process contain various contaminants released at sufficient rates to cause both short- and long-term health problems. Studies have shown that these fumes change the quality and quantity of semen fluid in exposed workers. The aim of the present study was to determine the potentially toxic effects of solder fumes on spermatogenesis in seminiferous tubules of rats as an experimental model, with conditioned media in an exposed chamber. Materials and Methods: A total number of 48 male Sprague Dawley adult rats were randomly divided into experimental (n=30) and control (n=18) groups. Based on exposure time, each group was further subdivided into two, four and six subgroups. Rats in the experimental groups were exposed to solder fumes in an exposure chamber for one hour/ day. The concentrations of fumes [formaldehyde, stanum (Sn) and lead (Pb)] were measured by a standard method via atomic absorption and spectrophotometry. According to a timetable, under deep anesthesia, the rats of both experimental and control subgroups were killed. After fixation of testes, specimens were weighed and routinely processed. Paraffin sections were stained by hematoxylin and eosin. Spermiogenesis index was calculated and data analyzed by Mann Whitney NPAR test. Results: Analysis of air samples in the exposure chamber showed the following fume concentrations: 0.193 mg/m3 for formaldehyde, 0.35 mg/m3 for Sn and 3 mg/m3 for Pb. Although there was no significant difference in testes weight between control and experimental subgroups, there was only a significant difference in spermiogenesis index between the six week experimental and control subgroups (p<0.02). Conclusion: The results of this study showed that solder fumes can change the spermiogenesis index in experimental groups in a time dependent manner.
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Wentlent, Luke A., James Wilcox, and Mohammed Genanu. "Applicability of Selective Laser Reflow for Thin Die Stacking." International Symposium on Microelectronics 2018, no. 1 (October 1, 2018): 000741–47. http://dx.doi.org/10.4071/2380-4505-2018.1.000741.
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Abstract A 3-D packaging approach such as die stacking is an attractive way to package greater functionality and performance into a smaller footprint, often at a reduced overall product cost. Achieving such 3-D integration can however place significant demands on the manufacturing process, often requiring substantial production expense to bond multiple die in a sequential manner. One alternative, potentially offering significant throughput, is the use of selective laser reflow to bond stacked die. This process produces a localized heating of the stacked die sufficient to produce soldered interconnects at the bonding interface but with very short exposure times that minimize the heating of other parts of the assembly and decrease the overall duration of the bonding process. The use of a commercial infrared (IR) laser reflow instrument for the sequential attachment of thin die into a 3-D stack was considered. The bonding technology under study consists of an infrared laser coupled with a custom optics system that allows the laser beam to be shaped into a range of rectangular shapes and sizes. This allows for a single device or target area to be selectively heated and reflowed while other regions in the near vicinity are not. The target reflow area is exposed to a shaped laser beam for a combination of laser powers and exposure times according to the desired thermal profile. The top most materials absorb the IR energy of the incident laser and conduct that thermal energy down to the solder joints and into rest of the assembly. The rates of heat transfer realized depend significantly upon the sample geometry and material composition. Since this produces a highly accelerated reflow, typically 2–8 seconds, the entire process is highly transient in nature. This paper reports on the investigation into the utility of a selective area laser reflow process to sequentially bond thin die into a multi-chip stack. Thin silicon die (~60μm thick) were bonded to a 150μm thick laminate substrate using a selected area laser reflow process. The die interconnects were formed through the soldering of SnAg capped copper pedestals under the local laser heat. First level die were placed onto copper pads on the laminate and then bonded using the laser process. Subsequent die (2nd level) were placed on and bonded to gold plated nickel pad sites on the top of the first level die. At each step of the process the quality of the solder interconnects was examined using optical and electron microscopy. A range of laser profiles were utilized with several different thermal parameters: peak temperatures ranging from 235–255°C, time above liquidus between 1–3 seconds, and a fixed cooling rate of 40°C/s. Control samples of stacked die were assembled using conventional manufacturing techniques to enable direct comparisons of the interconnects and die bonding characteristics.
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Dasgupta, Arnab, Elaina Zito, and Ning-Cheng Lee. "Voiding Control at Preform Soldering." International Symposium on Microelectronics 2016, no. 1 (October 1, 2016): 000630–37. http://dx.doi.org/10.4071/isom-2016-thp43.
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Abstract Assembly of components with large pads such as high brightness LEDs or high power dies often is soldered with preform, mainly due to a lower voiding and lower flux fume generated when compared with solder paste, and also because of its better thermal and electrical conductivity compared with Ag epoxy. This is particularly true when the joints are to be formed within a cavity. Although lower than solder paste, the voiding in the solder joint is still a concern for high reliability and high performance devices. In this study, voiding at high power die attach reflow soldering using preform was simulated with the use of Cu coupons to mimic both die and substrate. The voiding behavior was studied by varying solder alloy type, flux quantity coated on preform, oxidation extent of Cu coupon, reflow peak temperature, and weight applied on the top of simulated die. For SAC305, with increasing weight, the bondline thickness (BLT) maintained constant initially due to solder surface tension, then reduced rapidly at weight higher than 50 g. The voiding area % increased with decreasing BLT first, then levelled off at lower BLT, although the voiding volume decreased with decreasing BLT due to constrained lamellar solder flow. Voiding was the highest for SAC305, followed by 57Bi42Sn1Ag, with 63Sn37Pb being the lowest, and increased with increasing oxidation of Cu coupon. With increasing flux quantity, voiding increased for SAC305 and 63Sn37Pb, but decreased for 57Bi42Sn1Ag, mainly due to the different temperature range at reflow. Voiding increased with increasing reflow temperature up to 170°C due to increasing vaporization, decreased with further increase in reflow temperature up to 210°C due to increasing flux activity, and increased again at temperature beyond 210°C due to rapid flux outgassing.
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Lin, Keh Moh, Yang Hsien Lee, Wen Yeong Huang, Po Chun Hsu, Chin Yang Huang, and Zhu Fu Hsieh. "A Comparative Study of Soldering Temperatures and Materials on the Reliability of Photovoltaic Modules." Advanced Materials Research 562-564 (August 2012): 188–91. http://dx.doi.org/10.4028/www.scientific.net/amr.562-564.188.
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To find out the important factors which decisively affect the soldering quality of photovoltaic modules, solar cells were soldered under different conditions (different temperatures, PbSn vs. SnAgCu solder, manual vs. semi-automatic). Experimental results show that the soldering quality of PbSn under 350°C in the semi-automatic soldering process was quite stable while the soldering quality of lead-free solder was generally unacceptable in the manual or semi-automatic process under different temperatures. This result indicates that the soldering process with lead-free solder still needs to be further improved. It was also found that most cracks were formed on the interface between the solder and the silver paste and then expanded outwards.
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Hanss, Alexander, and Gordon Elger. "Residual free solder process for fluxless solder pastes." Soldering & Surface Mount Technology 30, no. 2 (April 3, 2018): 118–28. http://dx.doi.org/10.1108/ssmt-10-2017-0030.
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Purpose For soldering, flux is essential because it enables the wetting of the molten solder. Fluxless soldering, i.e. residue-free soldering with the aid of gaseous activators, has been known for many years, but is only well established in the field of opto- and microwave electronics where the solder is applied as preform. In high-volume SMD applications where solder paste is printed, this technology is rarely used until now. The reducing effect of a gaseous activator like formic acid vapor on certain solder alloys is known in practice. However, the corresponding reactions which occur under soldering conditions in nitrogen atmosphere have so far not been systematically investigated for different solder alloys. This study aims to analyze the different chemical reaction channels which occur on the surface of different solders, i.e. catalytical dissociation of formic acid on the pure or oxidized metal surface and the formation and evaporation of metal formates. Based on this analysis, a residue-free solder process under formic acid is developed for solder paste applications. Design/methodology/approach In this paper, different solder alloys (SnAgCu, SnPb, BiSn, In) were analyzed with thermal gravimetric analysis (TGA) under formic acid flow. Details on mass change depending on the soldering temperature are presented. Activation temperatures are estimated and correlated to the soldering processes. Based on the analysis, fluxless solder pastes and suitable soldering processes are developed and presented. Major paste properties such as printability are compared to a commercial flux solder paste. High-power flip chip LEDs which can be assembled directly on a printed circuit board are used to demonstrate the fluxless soldering. Likewise, the soldering results of standard paste and fluxless paste systems after a reflow process are evaluated and compared. Findings The experimental results show that TGA is an efficient way to gain deeper understanding of the redox processes which occur under formic acid activation, i.e. the formation of metal formates and their evaporation and dissociation. It is possible to solder residue-free not only with preforms but also with a fluxless solder paste. The resulting solder joints have the same quality as those for standard solder paste in terms of voids detected by X-ray and mechanical shear strength. Originality/value In the fluxless soldering process, the reduction of oxide layers, and therefore the wetting of the solder spheres, is enabled by gaseous formic acid. After the soldering process, no cleaning process is necessary because no corrosive residues are left on the circuit boards and components. Therefore, soldering using solder paste without aggressive chemical ingredients has a high market potential. Expensive preforms could be replaced by paste dispensing or paste printing.
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Fonseka, C. L. S. C., and J. A. K. S. Jayasinghe. "Localization of component lead inside a THT solder joint for solder defects classification." Journal of Achievements in Materials and Manufacturing Engineering 2, no. 83 (August 1, 2017): 57–66. http://dx.doi.org/10.5604/01.3001.0010.7033.
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Purpose: Automatic Optical Inspection (AOI) systems, used in electronics industry have been primarily developed to inspect soldering defects of Surface Mount Devices (SMD) on a Printed Circuit Board (PCB). However, no commercially available AOI system exists that can be integrated to a desktop soldering robotic system, which is capable of identifying soldering defects of Through Hole Technology (THT) solder joints along with the soldering process. In our research, we have implemented an AOI platform that is capable of performing automatic quality assurance of THT solder joints in a much efficient way. In this paper, we have presented a novel approach to identify soldering defects of THT solder joints, based on the location of THT component lead top. This paper presents the methodologies that can be used to precisely identify and localize THT component lead inside a solder joint. Design/methodology/approach: We have discussed the importance of lead top localization and presented a detailed description on the methodologies that can be used to precisely segment and localize THT lead top inside the solder joint. Findings: It could be observed that the precise localization of THT lead top makes the soldering quality assurance process more accurate. A combination of template matching algorithms and colour model transformation provide the most accurate outcome in localizing the component lead top inside solder joint, according to the analysis carried out in this paper. Research limitations/implications: When the component lead top is fully covered by the soldering, the implemented methodologies will not be able to identify the actual location of it. In such a case, if the segmented and detected lead top locations are different, a decision is made based on the direction in which the solder iron tip touches the solder pad. Practical implications: The methodologies presented in this paper can be effectively used to have a precise localization of component lead top inside the solder joint. The precise identification of component lead top leads to have a very precise quality assurance capability to the implemented AOI system. Originality/value: This research proposes a novel approach to identify soldering defects of THT solder joints in a much efficient way based on the component lead top. The value of this paper is quite high, since we have taken all the possibilities that may appear on a solder joint in a practical environment.
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SHI, JIANWEI, PENG HE, and XIAOCHUN LV. "CONTROLLING AND OPTIMIZATION OF THERMAL PROFILE IN REFLOW SOLDERING." International Journal of Modern Physics B 23, no. 06n07 (March 20, 2009): 1949–55. http://dx.doi.org/10.1142/s0217979209061883.
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Heating factor, Q is a quantitative parameter describing a process of reflow soldering. It can be used to evaluate a reflow soldering process and the reliability of solder joints. The value of Q is directly related to the energy absorbed by solder joint during heating and the morphology of Intermetallic Compound formed at the interface between solder and pad. Electronic product manufacturers use heating factor as a technical evaluation parameter to guide the adjustment of reflow soldering process and the optimization of reflow soldering curve, to ensure the best reliability of the circuit board. Solder paste manufacturers use heating factor to represent characteristics of their reflow soldering products, and to customize products according to consumer's requests. Equipment manufacturers for reflow soldering use heating factor as an important controlling parameter to establish automatic system for managing solder joint reliability. A reliable soldering result can be achieved using the automatic reflow management system, to control and optimize thermal profile, which leads to the adjustment of the heating factor.
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Wang, Wan Gang, and Yong Peng. "Solder Selection of Lead-Free Reflow Soldering and Optimization of Craft Curve." Advanced Materials Research 323 (August 2011): 70–74. http://dx.doi.org/10.4028/www.scientific.net/amr.323.70.
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Lead-free reflow soldering craft is the most important solder craft in surface mount technology at present. However, the great reduction of crafting window brings challenges to the soldering quality and also poses higher requirement for the stability and reliability of lead-free soldering equipment. This article analyzes problems out of lead-free process, introduces the selecting principle of lead-free solder and analyzes the optimizing gist of temperature curve of lead-free reflow soldering.
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Marciniak, Monika, Michael Meagher, Jon Davis, and Jack Josefowicz. "FAILURE ANALYSIS OF DISCOLORED ENIG PADS IN THE MANUFACTURING ENVIRONMENT." International Symposium on Microelectronics 2014, no. 1 (October 1, 2014): 000653–61. http://dx.doi.org/10.4071/isom-wp24.
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Manufacturing of electronic assemblies using printed circuit boards (PCBs) with electroless nickel/immersion gold (ENIG) surface finishes requires front-end PCB evaluation that will guarantee that good quality product enters the assembly line. The most common is an IPC-4552 mandated plating thicknesses verification of 3-6μm and a minimum of 0.05μm for nickel and gold, respectively. Coupled with visual examination, this verification method suffices for general PCB acceptance but may not be robust enough in cases where ENIG plating in PCBs is compromised. That poses challenges in the manufacturing environment, where resulting latent defects are detected in downstream processes but not at upfront incoming inspection. Manifestation of such latent anomaly was observed in the form of ENIG pad discoloration with variations from yellow, red or grey discolored surfaces to a more pronounced plating degradation, such as corrosive pitting. The launched failure analysis involved evaluation of manufacturing processes suspected to contribute to the cause of the condition. Effects of thermal processes, cleaning methods, soldering, parylene deposition and factory cleanliness were examined thoroughly. Concurrently, metallurgical analysis of ENIG pads was performed, where samples were subjected to scanning electron microscopic/energy dispersive x-ray spectroscopic (SEM/EDX) cross section analysis, Auger electron spectroscopy (AES) and gold (Au) and electroless nickel (Ni) surface examination. The resulting analysis revealed a highly porous electroless nickel coating with deep crevasses and fissures penetrating down to the base copper (Cu) layer. These open nickel boundaries were attributed to the corrosive environment within ENIG plating, which resulted in the pad surface discoloration. The root cause of ENIG pad discoloration and pitting was traced back to poor ENIG line process controls. Subsequent introduction of a nickel controller into the ENIG line were the implemented countermeasures. To mitigate the effects of discoloration at the electronic assembly level, a tinning process was implemented to prevent nickel plating oxidation and to ensure that good wettability for reliable solder joints was maintained.
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Mikhnev, M. M., I. V. Kudryavtsev, and P. N. Silchenko. "Theoretical Justification and Analysis of Technology for Manufacturing Waveguide-and-Distribution Systems of Spacecraft Communication Devices." Proceedings of Higher Educational Institutions. Маchine Building, no. 06 (723) (June 2020): 51–66. http://dx.doi.org/10.18698/0536-1044-2020-6-51-66.
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Manufacturing of extended thin-walled waveguide-and-distribution system (WDS) by soldering separate elements is associated with force, strain and temperature impacts leading to undesirable deformations both in local areas as well as in the whole structure. Each element and the system in general are subjected to local thermal exposure that results in temperature stresses and strains. The stresses that occur due to heating can cause irreversible deformations of the structure manifested as local deflections and distortions of the cross section geometry. When assembling waveguide-and-distribution systems, even minor angular and linear displacements in the places where the elements are joined result in disruption of the overall geometry of the structure and therefore, a displacement of the mounting points relative to the desired location. Forced alignment of these points would create internal stresses, which combined with external impacts, could violate the conditions of strength, rigidity and location of the control mounting points. To achieve the required strength, rigidity and accuracy parameters of the system, it is necessary to perform a theoretical and calculation analysis of the manufacturing process parameters, steps, actions and methods. The paper presents a method of calculating waveguide-and-distribution systems that can be used to promptly determine the stress-strain state with a required accuracy in order to ensure strength, rigidity and sufficient geometrical accuracy of the WDS structure. The WDS is treated as a rod model in the global formulation and as a shell structure when a separate local area is analyzed in detail. This approach enables the assessment of the stress-strain state in general and more precise calculations of the stresses and strains in defined local areas with nearly any required accuracy. An example showing calculations of the dynamics of variation of the gap between thin-walled elements in the process of soldering is given. An analysis of the stress-strain state of the mounting soldered seam between the elements is performed. The results obtained using the proposed two-step calculation method provide the required quality throughout the whole process of manufacturing an extended waveguide-and-distribution system for a spacecraft.
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Peng, Yong, Wan Gang Wang, and Xiao Ping Wang. "Genesis Analysis of Common Defects of Reflow Soldering and Research for Solutions." Advanced Materials Research 323 (August 2011): 79–83. http://dx.doi.org/10.4028/www.scientific.net/amr.323.79.
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To guarantee the quality of surface mounting electronic products, this article analyzes the process features of its four working zones, discusses some main factors which influences the soldering quality of reflow soldering, analyzes the common soldering defects and their causes according to the temperature and process features of reflow soldering during the process of reflow soldering like row-up, bridging, wicking and solder balling. By these measurements, appearance frequency of reflow soldering is effectively reduced and quality of surface mounting electronic products is also raised.
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Lea, C., and F. H. Howie. "Controlling the Quality of Soldering of PTH Solder Joints." Circuit World 11, no. 3 (February 1985): 5–7. http://dx.doi.org/10.1108/eb045996.
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Freitas, Maria Perpétua Mota, Hugo Mitsuo S. Oshima, Luciane M. Menezes, Denise C. Machado, and Christian Viezzer. "Cytotoxicity of Silver Solder Employed in Orthodontics." Angle Orthodontist 79, no. 5 (September 1, 2009): 939–44. http://dx.doi.org/10.2319/101108-530.1.
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Abstract Objective: To test the null hypothesis that the silver soldering employed in orthodontics is not cytotoxic for fibroblasts. Materials and Methods: This in vitro study was performed using a culture of mice fibroblasts (lineage NIH/3T3), divided into four groups (n = 10 each): control, negative control (stainless steel archwire), positive control (amalgam disks), and test group (silver soldering). After cell culture in complete Dulbecco modified eagle medium and achievement of confluence in 80%, the suspension was added to the plates of 24 wells containing the specimens and incubated in an oven at 37°C for 24 hours. The plates were analyzed on an inverted light microscope, photomicrographs were obtained, and the results were recorded as response rates based on modifications of the parameters of Stanford according to the size of the diffusion halo of the toxic substance and quantity of cell lysis. Results: The results revealed a maximum response rate for the silver soldering group, as well as severe inhibition of cell proliferation and growth, more round cells with mostly darkened and granular aspects, suggesting lysis with cell death. A similar response was seen in the positive control group. Conclusion: The hypothesis is rejected. The silver soldering used in orthodontics represents a highly cytotoxic material for the cells analyzed.
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Koscielski, Marek, and Janusz Sitek. "Influence of the fluxes properties on quality and the microstructure of lead-free solder joints executed by selective soldering." Soldering & Surface Mount Technology 26, no. 1 (January 28, 2014): 2–7. http://dx.doi.org/10.1108/ssmt-10-2013-0031.
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Purpose – The purpose of this paper is to investigate the influence of the properties of new compositions of fluxes for selective soldering on lead-free solder joints quality and microstructures as well as showing which flux properties are the most important. Design/methodology/approach – The three different types of fluxes were tested, which differed in composition, solids content, amount and type of activators added. The selective soldering process was done with the use of lead-free solder SAC 305. The test boards had two coatings SnCu (HASL) or Au/Ni. Basic chemical and physical properties of fluxes were examined according to the relevant standards. Different types of components from the bulky ones, demanding more heat, to the smaller ones were used during the assembly process. AOI and X-ray analyses as well as cross-sections and SEM analyses were utilized to deeply assess the quality and microstructure of the investigated solder joints. Findings – The results showed that information about density or static activity of flux is not enough for correct flux assessment. The dynamic activity of flux measured by wetting balance method is the best for this, especially in the case when there is short soldering time and heat transfer is hindered. The quality and the microstructure of lead-free solder joints are related not only with wetting properties of the flux used for soldering but also with other properties like solids content in a flux. Research limitations/implications – It is suggested that further studies are necessary for the confirmation of the practical application, especially of the reliability properties of the joints obtained with the use of the elaborated fluxes. Originality/value – The results showed that type of flux (ORL or ROL) as well as minor changes in their dynamic activity and solids content might have significant influence on quality of solder joints and their microstructure. It was noted that selective soldering is demanding technique and optimization of soldering process for different type of components and fluxes is important.
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Hui, I. K., and B. Ralph. "A study of the strength and shape of surface mount technology leadless chip solder joints." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 211, no. 1 (January 1, 1997): 29–41. http://dx.doi.org/10.1243/0954405971516059.
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A method that directly pulled the components off printed circuit boards was used as a means for testing the bond quality of surface mount technology leadless chip solder joints. Components D7243, CC1206, RC1206, RC1210 and CC1812 were selected for the study. It was found that the ultimate tensile force that breaks a component off the printed circuit board has the potential to be used as a parameter for measuring the quality of the solder joint. The failure modes of the joints were recorded and are discussed. The effect of solder thickness on the strength of a joint has also been investigated. The shape of joints soldered by two methods, wave soldering and infra-red reflow, were compared. Joints at the two ends of a component produced by infra-red reflow were found to be more uniform than the ones produced by wave soldering. A recommendation is made here for the wave soldering approach in achieving uniform solder joints. The effects of solder shape on the joint strength were further investigated by finite element analysis. A convex joint was found to be marginally more robust than a concave joint.
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Podsiadły, Bartłomiej, Andrzej Skalski, and Marcin Słoma. "Soldering of Electronics Components on 3D-Printed Conductive Substrates." Materials 14, no. 14 (July 9, 2021): 3850. http://dx.doi.org/10.3390/ma14143850.
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Rapid development of additive manufacturing and new composites materials with unique properties are promising tools for fabricating structural electronics. However, according to the typical maximum resolution of additive manufacturing methods, there is no possibility to fabricate all electrical components with these techniques. One way to produce complex structural electronic circuits is to merge 3D-printed elements with standard electronic components. Here, different soldering and surface preparation methods before soldering are tested to find the optimal method for soldering typical electronic components on conductive, 3D-printed, composite substrates. To determine the optimal soldering condition, the contact angles of solder joints fabricated in different conditions were measured. Additionally, the mechanical strength of the joints was measured using the shear force test. The research shows a possibility of fabricating strong, conductive solder joints on composites substrates prepared by additive manufacturing. The results show that mechanical cleaning and using additional flux on the composite substrates are necessary to obtain high-quality solder joints. The most repeatable joints with the highest shear strength values were obtained using reflow soldering together with low-temperature SnBiAg solder alloy. A fabricated demonstrator is a sample of the successful merging of 3D-printed structural electronics with standard electronic components.
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Takemoto, Tadashi. "High Dissolution Rate of Solid Materials in Molten Lead-Free Solders." Materials Science Forum 580-582 (June 2008): 205–8. http://dx.doi.org/10.4028/www.scientific.net/msf.580-582.205.
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Sn-based lead-free solders have some characteristics that are different from the conventionally used Sn-Pb eutectic. One is the high dissolution rate of metals and alloys into molten lead-free solder. Several problems due to this high dissolution rate were reviewed. The prominent materials that suffered from this high dissolution rate are copper and iron based. High dissolution rate of Cu resulted in thick Cu-Sn intermetallic compound formation during soldering and Cu enrichment in wave soldering bath. The iron-based materials used for soldering equipments are damaged by erosion. Suppression of the dissolution rate is important to secure quality of micro-soldered joints, to prevent contamination of solder bath and to prolong the life of soldering equipments. The method of suppressing dissolution in practical soldering operation and some examples of erosion damage are introduced.
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LIN, KEH-MOH, YANG-HSIEN LEE, LI-KUO WANG, LI-WEI CHEN, SIAN-YI YANG, YI-CHIA CHEN, DE-CHIH LIU, MING-YUAN HUANG, ZHEN-CHENG WU, and CHIEN-PIN CHEN. "ELECTROLUMINESCENCE OBSERVATION OF MICROCRACK GROWTH BEHAVIOR OF CRYSTALLINE SILICON SOLAR MODULES FABRICATED BY HOT-AIR SOLDERING TECHNOLOGY." International Journal of Modern Physics: Conference Series 06 (January 2012): 43–48. http://dx.doi.org/10.1142/s2010194512002917.
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In this study, the quality degradation of Si -based photovoltaic (PV) modules during the aging process was observed by using electroluminescent (EL) technology and was verified by the IV curve measurements in order to find out the occurring timing of damages on solar cells. Furthermore, the influences of solder materials and soldering temperatures on the performance of the PV modules were also studied. Experiment results show that, high soldering temperatures which induce high thermal stress can easily lead to the power loss of the PV modules. Besides, the mechanical properties of the solar cells itself can also affect the degradation rate of the PV modules. On PV modules soldered with SnPb (SP) solder, more than 80% of cell damages occurred during the soldering and encapsulation processes. When SnAgPb (SAP) solder was used, a small part of the cell damages didn't emerge until the initial stage of the thermal cycling test (TC.) This phenomenon is attributed to the reduction of residual stress between the ribbon and the silver paste because of the good wettability of SAP solder.
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Illés, Balázs, Attila Géczy, Bálint Medgyes, and Gábor Harsányi. "Vapour phase soldering (VPS) technology: a review." Soldering & Surface Mount Technology 31, no. 3 (June 3, 2019): 146–56. http://dx.doi.org/10.1108/ssmt-10-2018-0042.
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Purpose This paper aims to present a review of the recent developments in vapour phase soldering (VPS) technology. This study focuses on the following topics: recent developments of the technology, i.e. soft and vacuum VPS; measurement and characterization methods of vapour space, i.e. temperature and pressure; numerical simulation of the VPS soldering process, i.e. condensate layer and solder joint formation; and quality and reliability studies of the solder joints prepared by VPS, i.e. void content and microstructure of the solder joints. Design/methodology/approach This study was written according to the results of a wide literature review about the substantial previous works in the past decade and according to the authors’ own results. Findings Up to now, a part of the electronics industry believes that the reflow soldering with VPS method is a significant alternative of convection and infrared technologies. The summarized results of the field in this study support this idea. Research limitations/implications This literature review provides engineers and researchers with understanding of the limitations and application possibilities of the VPS technology and the current challenges in soldering technology. Originality/value This paper summarizes the most important advantages and disadvantages of VPS technology compared to the other reflow soldering methods, as well as points out the necessary further developments and possible research directions.
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Borecki, Janusz, and Tomasz Serzysko. "Mechanical reliability of solder joints in PCBs assembled in surface mount technology." Soldering & Surface Mount Technology 28, no. 1 (February 1, 2016): 18–26. http://dx.doi.org/10.1108/ssmt-10-2015-0037.
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Purpose – The purpose of this paper is to determine the dependence of mechanical strength of solder joints on printed circuit boards from the soldering process parameters and operating conditions of the electronic device. Design/methodology/approach – The research was performed using the Taguchi method of planning of experiments. Evaluation of the quality of solder joints was made on the basis of microscopic observations, X-ray analysis and measurements of shear force of solder joints. Findings – The carried out research has shown the influence of the individual parameters of the soldering process on the mechanical strength of solder joints and the mechanism of damage of solder joints under the influence of shear force. Originality/value – The authors present results of their research using advanced techniques of experimental design and analysis of results. In this study, original approach was used to simulate the operational conditions of electronic devices including thermal imaging technology.
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Ismail, Norliza, Azman Jalar, Maria Abu Bakar, Roslina Ismail, and Najib Saedi Ibrahim. "Effect of flux functional group for solder paste formulation towards soldering quality of SAC305/CNT/Cu." Soldering & Surface Mount Technology 32, no. 3 (February 7, 2020): 157–64. http://dx.doi.org/10.1108/ssmt-07-2019-0024.
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Purpose The purpose of this paper is to investigate the wettability and intermetallic (IMC) layer formation of Sn-3.0Ag-0.5Cu (SAC305)/CNT/Cu solder joint according to the formulation of solder paste because of different types of fluxes. Design/methodology/approach Solder pastes were prepared by mixing SAC305 solder powder with different flux and different wt.% of carbon nanotube (CNT). Fourier transform infrared spectroscopy was used to identify functional groups from different fluxes of as-formulated solder paste. The solder pastes were then subjected to stencil printing and reflow process. Solderability was investigated via contact angle analysis and the thickness of cross-sectionally intermetallic layer. Findings It was found that different functional groups from different fluxes showed different physical behaviour, indicated by contact angle value and IMC layer thickness. “Aromatic contain” functional group lowering the contact angle while non-aromatic contain functional group lowering the thickness of IMC layer. The higher the CNT wt.%, the lower the contact angle and IMC layer thickness, regardless of different fluxes. Relationship between contact angle and IMC layer thickness is found to have distinguished region because of different fluxes. Thus it may be used as guidance in flux selection for solder paste formulation. Research limitations/implications However, detail composition of the fluxes was not further explored for the scope of this paper. Originality/value The quality of solder joint of SAC305/CNT/Cu system, as indicated by contact angle and the thickness of IMC layer formation, depends on existence of functional group of the fluxes.
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Branzei, Mihai, and Ioan Plotog. "Thermophysical Properties in Assembling Process at Macro and Micro Level." Advanced Materials Research 1114 (July 2015): 172–79. http://dx.doi.org/10.4028/www.scientific.net/amr.1114.172.
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The electronic modules are complex ensemble of electronic components having terminals (PIN) connected by solder joints on dedicated metallic surfaces (PAD) parts of conductive interconnection structure realized on rigid or flexible dielectric substrate having different core materials. The reliability of the electronic modules could be considered as expression of solder joints functionality (SJF) relating to working conditions and unique defined by their electrical, mechanical and thermal properties. These properties are in close connection with the solder joints microstructures, result of the soldering Process temperature gradient action over the trinomial solder alloy Paste, Pin and Pad. Consequently the solder joints quality can be correctly evaluated taking into consideration not only the severally intrinsic parameters of the trinomial elements Pin-Pad-Paste characterized by specific thermophysical properties (ThP), but also interrelate the complex reaction at the interface between them and interdependence with the soldering Process parameters.In the paper, will be analyzed the influencing factors of manufacturing processes, the most important assembling defects at macro and micro level, their causes relating to specific ThP and processes at interfaces Pin-solder joints-Pad, it will be identify the Key Process Input Variables (KPIV) and propose a structural model for assembling processes, 4P Soldering Model, as an useful tool in engineering of electronic product in order to assure the assumed goal for assembling stage.
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Kinga Synkiewicz, Beata, Agata Skwarek, and Krzysztof Witek. "Voids investigation in solder joints performed with vapour phase soldering (VPS)." Soldering & Surface Mount Technology 26, no. 1 (January 28, 2014): 8–11. http://dx.doi.org/10.1108/ssmt-10-2013-0028.
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Purpose – The main advantages of vapour phase soldering are a non-oxygen environment, the elimination of overheating and the possibility of the vacuum application, which can guarantee undeniably higher quality of solder joints, especially as regards void formation. These features are less affected by the alloy composition. The paper aims to discuss these issues. Design/methodology/approach – The quality of solder joints made in two VPS options (with and without vacuum) was investigated in terms of voids formation. Solder alloys of 37%Pb63%Sn (PbSn) and 96%Sn3.5%Ag0.5%Cu (SAC 305) were applied to an etched Cu layer on a glass-epoxy substrate using the screen-printing method. 1206 SMD resistors were placed on the solder pads with a Quadra pick-and place machine. For the inspection of joint structure and void identification, 3D X-ray images of samples were taken using a computed tomography system with a 180 kV/15 W nanofocus. For comparison, traditional cross-sections of the samples were performed using a metallographic polisher. The cross-section analysis was done in a scanning electron microscope (SEM). To confirm the relevance of these data, a statistical analysis was carried out. Findings – The paper shows that alloy composition has less impact on the quality of joints as regards void formation. The tendency for a different arrangement of voids in a junction depending on the distance SMD element and the thickness of the solder layer was investigated using X-ray computed tomography. Originality/value – The use of 3D computed tomography for void investigation gives full information about the internal structure of the joint and allows for precise void identification. Vacuum application during the soldering allows significant voids elimination.
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Li, Yang, Di Wu, Yabin Zhang, Liujue Wang, and Songbai Xue. "Effects of Trace Oxygen Content on Microstructure and Performances of Au-20Sn/Cu Solder Joints." Crystals 11, no. 6 (May 26, 2021): 601. http://dx.doi.org/10.3390/cryst11060601.
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The Au-20Sn solder is widely used in the packaging of high-end electronic products, and the requirement on the reliability of the solder joints is more and more strict with a continuous increase in the performance of the package products. As the oxygen content in the Au-Sn solder is a key factor dominating the quality of fluxless packaging, in this study, the wettability and spreading performance of the Au-20Sn solder with different oxygen contents and the interfacial microstructure, mechanical properties, gas tightness and ratio of soldering area of the Au-Sn/Cu solder joints prepared using these solders were comprehensively investigated to clarify the effects of trace oxygen content. The results reveal that the wetting and spreading performances of the solder decrease sharply with increasing oxygen conte[nt. When the oxygen content increased from 18 to 77 ppm, the spreading area of the solder on the Cu substrate decreased from 92.8 to 49.2 mm2, reducing by 47%. Meanwhile, pores and microcracks appear in the solder joint with relatively high oxygen content, making the shear strength decrease from 56.6 to 31.7 MPa. The oxygen also greatly affects the gas tightness and ratio of soldering area. For the optical window packaged using Au-Sn solder containing 40 ppm of oxygen, the leakage rate was higher than 5 × 10−11 mbar·m−3·s−1 and cannot fulfill the requirements. With increasing oxygen content in the Au-Sn solder, the cleanliness of the chip packaged with these solders deteriorated, and the solder surface was obviously oxidized. When the oxygen content was 18 ppm, the ratio of soldering area was 92%, but decreased sharply to 53% when the oxygen content increased to 77 ppm. It is demonstrated that an oxygen content lower than 27 ppm is required for the Au-20Sn solder used in fluxless packaging.
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Khazaka, Rabih, Donatien Martineau, Toni Youssef, Thanh Long Le, and Stéphane Azzopardi. "Rapid and Localized Soldering Using Reactive Films for Electronic Applications." Journal of Microelectronics and Electronic Packaging 16, no. 4 (October 1, 2019): 182–87. http://dx.doi.org/10.4071/imaps.955217.
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Abstract The rapid and localized heating techniques allow the joining of temperature-sensitive materials and components without thermal induced damage commonly encountered when high-temperature solder reflow processes are used. This is also advantageous for making assemblies with materials having a large difference in the coefficient of thermal expansion without induced bowing or cracking. The use of exothermic reactive foil sandwiched between solder preforms is a promising local and rapid soldering process because it does not require any external heat source. The reactive foil is formed from alternatively stacked nanolayers of Ni and Al until it reaches the total film thickness. Once the film is activated by using an external power source, a reaction takes place and releases such an amount of energy that is transferred to the solder preforms. If this amount of energy is high enough, solder preforms melt and insure the adhesion between the materials of the assembly. The influences of the applied pressure, the reactive film (RF) thickness as well as the solder, and the attached materials chemical composition and thickness were investigated. It was shown that the applied pressure during the process has a strong effect on the joint initial quality with voids ratio decreases from 64% to 26% for pressure values between .5 and 100 kPa, respectively. This can be explained by the improvement of the solder flow under higher pressure leading to a better surface wettability and voids elimination. Otherwise, the joint quality was found to be improved once the solder melting duration is increased. This relationship was observed when the thickness of the reactive foil is increased (additional induced energy) or the thickness of solders, Cu, and/or Si is decreased (less energy consumption). The microstructure of the AuSn joint achieved using the RFs shows very fine phase distribution compared with the one obtained using conventional solder reflow process in the oven because of high cooling rate. The mechanical properties of the joint were evaluated using shear tests performed on 350-μm-thick silicon diodes assembled on active metal brazed substrates under a pressure of 100 kPa. The RFs were 60 μm thick and sandwiched between two 25-μm-thick 96.5Sn3Ag.5Cu (SAC) preforms. The voids ratio was about 37% for the tested samples and shear strength values above 9.5 MPa were achieved which remains largely higher than MIL-STD-883H requirements. Finally, the process impact on the electrical properties of the assembled diodes was compared with a commonly used solder reflow assembly and the results show a negligible variation.
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Huang, Lijuan, Zhenghu Zhu, Hiarui Wu, and Xu Long. "Board-level vapor phase soldering (VPS) with different temperature and vacuum conditions." Multidiscipline Modeling in Materials and Structures 15, no. 2 (February 21, 2019): 353–64. http://dx.doi.org/10.1108/mmms-04-2018-0082.
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Purpose Vapor phase soldering (VPS), also known as condense soldering, is capable of improving the mechanical reliability of solder joints in electronic packaging structures. The paper aims to discuss this issue. Design/methodology/approach In the present study, VPS is utilized to assemble two typical packaging types (i.e. ceramic column grid array (CCGA) and BGA) for electronic devices with lead-containing and lead-free solders. By applying the peak soldering temperatures of 215°C and 235°C with and without vacuum condition, the void formation and intermetallic compound (IMC) thickness are compared for different packaging structures with lead-containing and lead-free solder alloys. Findings It is found that at the soldering temperature of 215°C, CCGA under a vacuum condition has fewer voids but BGA without vacuum environment has fewer voids despite of the existence of lead in solder alloy. In light of contradictory phenomenon about void formation at 215°C, a similar CCGA device is soldered via VPS at the temperature of 235°C. Compared with the size of voids formed at 215°C, no obvious void is found for CCGA with vacuum at the soldering temperature of 235°C. No matter what soldering temperature and vacuum condition are applied, the IMC thickness of CCGA and BGA can satisfy the requirement of 1.0–3.0 µm. Therefore, it can be concluded that the soldering temperature of 235°C in vacuum is the optimal VPS condition for void elimination. In addition, shear tests at the rate of 10 mm/min are performed to examine the load resistance and potential failure mode. In terms of failure mode observed in shear tests, interfacial shear failure occurs between PCB and bulk solder and also within bulk solder for CCGA soldered at temperatures of 215°C and 235°C. This means that an acceptable thicker IMC thickness between CCGA solder and device provides greater interfacial strength between CCGA and device. Originality/value Due to its high I/O capacity and satisfactory reliability in electrical and thermal performance, CCGA electronic devices have been widely adopted in the military and aerospace fields. In the present study, the authors utilized VPS to assemble a typical type of CCGA with the control package of conventional BGA to investigate the relation between essential condition (i.e. soldering temperature and vacuum) to void formation.
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Hu, Xiao Ming. "Critical Soldering Interconnect Technology in SMT." Applied Mechanics and Materials 713-715 (January 2015): 3001–6. http://dx.doi.org/10.4028/www.scientific.net/amm.713-715.3001.
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this paper introduced the important soldering interconnect technology in SMT. In electric product manufacturing process, sometime we must place components in through-hole ways , then we use wave soldering. Wave soldering is used for both through-hole printed circuit assemblies, and surface mount. As technology changing very soon, the through-hole components have been largely replaced by surface mount components, this time ,Reflow soldering is the most common method of attaching surface mount components to a circuit board,but not wave soldering also reflowing, we must focus on wetting , It quantifies the wettability of a solid surface by a liquid .wetting angle is a the important quantity (also called contact angle).it can judge the quality of solder joints.
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Veselý, Petr, Eva Horynová, Jiří Starý, David Bušek, Karel Dušek, Vít Zahradník, Martin Plaček, et al. "Solder joint quality evaluation based on heating factor." Circuit World 44, no. 1 (February 5, 2018): 37–44. http://dx.doi.org/10.1108/cw-10-2017-0059.
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Purpose The purpose of this paper is to increase the reliability of manufactured electronics and to reveal reliability significant factors. The experiments were focused especially on the influence of the reflow oven parameters presented by a heating factor. Design/methodology/approach The shear strength of the surface mount device (SMD) resistors and their joint resistance were analyzed. The resistors were assembled with two Sn/Ag/Cu-based and one Bi-based solder pastes, and the analysis was done for several values of the heating factor and before and after isothermal aging. The measurement of thickness of intermetallic compounds was conducted on the micro-sections of the solder joints. Findings The shear strength of solder joints based on the Sn/Ag/Cu-based solder alloy started to decline after the heating factor reached the value of 500 s · K, whereas the shear strength of the solder alloy based on the Bi alloy (in the measured range) always increased with an increase in the heating factor. Also, the Bi-based solder joints showed shear strength increase after isothermal aging in contrast to Sn/Ag/Cu-based solder joints, which showed shear strength decrease. Originality/value The interpretation of the results of such a comprehensive measurement leads to a better understanding of the mutual relation between reliability and other technological parameters such as solder alloy type, surface finish and parameters of the soldering process.
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Skwarek, Agata, Balázs Illés, Krzysztof Witek, Tamás Hurtony, Jacek Tarasiuk, Sebastian Wronski, and Beata Kinga Synkiewicz. "Reliability studies of InnoLot and SnBi joints soldered on DBC substrate." Soldering & Surface Mount Technology 30, no. 4 (September 3, 2018): 205–12. http://dx.doi.org/10.1108/ssmt-10-2017-0029.
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Purpose This paper aims to investigate the quality and reliability of solder joints prepared from Pb-free alloys on direct bounded Cu (DBC) substrates. Two types of solder alloys were studied: Sn90.95Ag3.8Cu0.7Sb1.4Ni0.15Bi3.0, with a high melting point of 225°C, and Sn42Bi58, with low a melting point of 138°C. Design/methodology/approach Capacitor components of size 1806 were soldered on DBC substrates by using convection reflow soldering and vacuum vapor-phase soldering technologies. A part of the samples was subjected to the thermal shock test. The structure of the solder joints and the content of the voids were investigated using three-dimensional X-ray tomography. The mechanical strength of the joints was evaluated using the shear force test, and the microstructure of the joints was studied on metallographic cross sections by using scanning electron microscopy. Findings It was found that the number of voids is not related directly to the mechanical strength of the solder joints. The mechanical strength of the solder joints depends more on the amount of Ag3Sn precipitation, Au precipitation and the intermetallic layer in the solder joints. In some cases, the thermal shock test caused micro-cracks around the Au precipitation because of a mismatch of Au, AuSn4 and Sn in terms of coefficients of thermal expansion. Originality/value DBC substrates are usually used for power electronics, where the quality of the solder joints is even more important than in the case of commercial electronics.
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Wang, Hong Mei, Lin Lu, Xiao Long Liu, and Feng Gao. "A Method Based on the Morphology of Lead-Free Solder Powder Adhesive Particle Segmentation." Advanced Materials Research 690-693 (May 2013): 2681–85. http://dx.doi.org/10.4028/www.scientific.net/amr.690-693.2681.
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Three kinds of lead-free soldering tin powder particles produced by means of ultrasonic vibration atomization were studied in this paper. For tin powder particles had higher edge angle and more irregular shape which were the two most key elements that may influence the quality of soldering paste, aspect ratio and fractal dimension of those particles were treated as the facts that could reflect the morphology of soldering tin powder particles. Geometrical projected images of those particles were acquired by optical microscope and image computing were processed by morphologic method. Since particles adhesion phenomenon often occurred in actual image processing of soldering tin powder particles, Roberts operator was used for edge detection and in the meantime, Erosion method and Dilation method in morphological operation were applied to segment those adhesive particles. It was shown that the morphologic method proposed in this paper could be applied to segment those images of adhesive particles.
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Tynchenko, Vadim S., Vyacheslav E. Petrenko, and Alexander V. Murygin. "Control of the induction soldering on the basis of process temperature indirect measurements." MATEC Web of Conferences 224 (2018): 01054. http://dx.doi.org/10.1051/matecconf/201822401054.
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The article suggests the use of indirect measurements to control the process of induction soldering. Based on the equations of thermodynamics, it is proposed a scheme for approximating the temperature values in the solder zone on the basis of information from pyrometric sensors aimed at an area remote from the soldered joint site. A model-algorithmic instrument for indirect temperature measurements in the soldering technological process is developed, the scheme of which is presented in the article. The software of waveguide paths induction soldering control in the form of an already existing system module has been developed, which allows not only to carry out experimental studies on control algorithms, but also to implement a full-scale experiment, the results of which confirm the effectiveness of the proposed approach.
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Lin, Keh Moh, Yang Hsien Lee, Wen Yeong Huang, Yi Wen Kuo, Li Kuo Wang, and Sian Yi Yang. "Long Term Reliability and Power Degradation Analysis of Multicrystalline Silicon Solar Modules Using Electroluminescence Technique." Advanced Materials Research 562-564 (August 2012): 90–93. http://dx.doi.org/10.4028/www.scientific.net/amr.562-564.90.
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In this study, the quality degradation of multi-crystalline silicon photovoltaic (PV) modules during the aging process was observed by using electroluminescence (EL) technology and IV curve measurements in order to find out the occurring timing of damages on solar cells. The influences of soldering materials and temperatures on the performance of the PV modules were also studied. Experimental data show that, high soldering temperatures which induce high thermal stress can easily lead to the power loss of the PV modules. On PV modules soldered with SnAgPb (SAP) solder, ca. 40% of module damages occurred after 25 cycles during the thermal cycling (TC) test. In contrast, there were 61.5% of damaged SnPb (SP) modules after the 25 TC. Most module damages which are attributed to the crack growth and the floating solder emerged during the soldering and encapsulation processes. In our experiment, the average power degradation of all modules was less than 10%.
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Sass, Jan-Oliver, Abdessalam Jakobi, Aurica Mitrovic, Cornelia Ganz, Jennifer Wilken, Ulrike Burmeister, Hermann Lang, Rainer Bader, and Danny Vogel. "Bending strength of ceramic compounds bonded with silicate-based glass solder." Materials Testing 63, no. 7 (July 1, 2021): 593–98. http://dx.doi.org/10.1515/mt-2020-0098.
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Abstract In the field of dental technology, the length of ceramic pontics is limited to avoid mechanical failure. To reduce thermal-induced residual stress within the ceramic, using smaller subcomponents and subsequent bonding with silicate-based glass solder may be a favorable approach. Thus, the bending strength of zirconia compounds bonded with different silicate-based glass solders was investigated. For this purpose, rectangular specimens made of zirconia were bonded by glass solder. Parameters such as the scarf angle (45° and 90°), two different glass solders, as well as the soldering process (pressure and surface treatment) were varied. All specimens were subjected to quasi-static four-point bending tests according to DIN EN ISO 843-1. Additionally, the quality of the glass solder connection was evaluated using μCT and fractography. In the present study, zirconia compounds were sucessful bonded of zirconia compounds using silicate-based glass solder was. No significant differences in terms of bending strength were observed with respect to the different bonding parameters analyzed. The highest bending strength of 130.6 ± 50.5 MPa was achieved with a 90° scarf angle combined with ethanol treatment of the specimens before soldering and an additional application of a pressure of 2 bars in a dental pressure pot before subsequent soldering. Nevertheless, the bending strengths were highly decreased when compared to monolithic zirconia specimens (993.4 ± 125.5 MPa).
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Esfandyari, Alireza, Aarief Syed-Khaja, Mark Horvath, and Jörg Franke. "Energy Efficiency Analysis of Vapor Phase Soldering Technology through Exergy-Based Metric." Applied Mechanics and Materials 805 (November 2015): 196–204. http://dx.doi.org/10.4028/www.scientific.net/amm.805.196.
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In electronics production, the condensation based soldering technologies are known for reproducible solder profiles and efficient heat transfer methodology. The recent advancements in lead-free soldering and requirements for absolute void-free interconnections to increase the reliability and lifetime of the product needs optimization of the soldering process. The vacuum assisted vapor phase soldering process addresses the requirements with respect to mass production and parallelly resource efficient production which is also the motivation for the present work. This study is devoted to quantify the resource consumption and qualify this consumption through exergy flows in a vacuum vapor phase reflow soldering technology in electronics manufacturing.The analysis implies on the saving potential for energy consumption specifically during the vacuum process which also defines the void reduction quality of solder joints. Exergy efficiency analysis of a temperature profile depicts the influence of the materials used in the demonstrator. Shortening the production lead‑time, and increasing the production rate increase the efficiency of exergy and prevents wastage of usable energy. Furthermore, the set-up improvements for the temperature profiles processes are necessary, and the changes toward developing new, transformational technologies in pre-heating and vacuum zones are mandatory if a high efficiency of resources used is aimed.
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Yang, Hong, He Wang, and Dingyue Cao. "Investigation of soldering for crystalline silicon solar cells." Soldering & Surface Mount Technology 28, no. 4 (September 5, 2016): 222–26. http://dx.doi.org/10.1108/ssmt-04-2015-0015.
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Purpose Tabbing and stringing are the critical process for crystalline silicon solar module production. Because of the mismatch of the thermal expansion coefficients between silicon and metal, phenomenon of cell bowing, microcracks formation or cell breakage emerge during the soldering process. The purpose of this paper is to investigate the effect of soldering on crystalline silicon solar cells and module, and reveal soldering law so as to decrease the breakage rates and improve reliability for crystalline silicon solar module. Design/methodology/approach A microscopic model of the soldering process is developed by the study of the crystalline silicon solar cell soldering process in this work. And the defects caused by soldering were analyzed systematically. Findings The defects caused by soldering are analyzed systematically. The optimal soldering conditions are derived for the crystalline silicon solar module. Originality/value The quality criterion of soldering for crystalline silicon solar module is built for the first time. The optimal soldering conditions are derived for the crystalline silicon solar module. This study provides insights into solder interconnection reliability in the photovoltaic (PV) industry.
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Yin, Feng Fu, Xi Hua Zhang, Hai Long Wang, and Sui Ran Yu. "Optimization of Process Parameters in Lead-Free Wave Soldering Based on Orthogonal Experiment and Analytic Hierarchy Process." Applied Mechanics and Materials 26-28 (June 2010): 641–47. http://dx.doi.org/10.4028/www.scientific.net/amm.26-28.641.
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In order to solve the typical soldering defects in lead-free wave soldering, the Design of Experiment(DOE) was conducted to optimize the process parameters. Based on the printed circuit board(PCB) experimental results, the method of Analytic Hierarchy Process(AHP) was employed to analyze the experiment results quantitatively. Then the influential weights of each factor in different levels were obtained. It is concluded that the influential sequences of the four main process parameters in lead-free wave soldering are track speed, flux quantity, soldering temperature and preheat temperature; the optimal process parameters are as follows: flux quantity 40mL•min-1, preheat temperature 110°C, track speed 1.6m•min-1, soldering temperature 265°C. Furthermore, the reasons of solder bridging and missing weld defects were discussed systematically according to the analysis results. This paper reveals the key direction to optimize the process parameters and provides an effective measure to improve the soldering quality in lead-free wave soldering.
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Sharizal Abdul Aziz, Mohd, Mohd Zulkifly Abdullah, and Chu Yee Khor. "Influence of PTH offset angle in wave soldering with thermal-coupling method." Soldering & Surface Mount Technology 26, no. 3 (May 27, 2014): 97–109. http://dx.doi.org/10.1108/ssmt-08-2013-0021.
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Purpose – The aim of this study is to investigate the effects of offset angle in wave soldering by using thermal fluid structure interaction modeling with experimental validation. Design/methodology/approach – The authors used a thermal coupling approach that adopted mesh-based parallel code coupling interface between finite volume-and finite element-based software (ABAQUS). A 3D single pin-through-hole (PTH) connector with five offset angles (0 to 20°) on a printed circuit board (PCB) was built and meshed by using computational fluid dynamics preprocessing software called GAMBIT. An implicit volume of fluid technique with a second-order upwind scheme was also applied to track the flow front of solder material (Sn63Pb37) when passing through the solder pot during wave soldering. The structural solver and ABAQUS analyzed the temperature distribution, displacement and von Mises stress of the PTH connector. The predicted results were validated by the experimental solder profile. Findings – The simulation revealed that the PTH offset angle had a significant effect on the filling of molten solder through the PCB. The 0° angle yielded the best filling profile, filling time, lowest displacement and thermal stress. The simulation result was similar to the experimental result. Practical implications – This study provides a better understanding of the process control in wave soldering for PCB assembly. Originality/value – This study provides fundamental guidelines and references for the thermal coupling method to address reliability issues during wave soldering. It also enhances understanding of capillary flow and PTH joint issues to achieve high reliability in PCB assembly industries.
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Esfandyari, Alireza, Aarief Syed-Khaja, Tallal Javied, and Jörg Franke. "Energy Efficiency Investigation on High-Pressure Convection Reflow Soldering in Electronics Production." Applied Mechanics and Materials 655 (October 2014): 95–100. http://dx.doi.org/10.4028/www.scientific.net/amm.655.95.
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One of the key factors in efficient and defect-free electronics manufacturing is the soldering of electronic components to the printed circuit boards. The deciding factor in the reliability and lifetime of the product is the quality of the soldered interconnections. The setting up of the reflow soldering profile plays a crucial role in the electrical functionality and robustness of the product. Especially the miniaturization of the assemblies and the development of new materials make it inevitable for the definition of new processes, optimization and implementation. In this paper, the combination of over-pressure and convection reflow soldering to minimize the defect rate and the related energy analysis for energy efficiency will be discussed and presented. A statistical analysis with variations in solder time, cost, energy, quality trade-off in the over-pressure reflow soldering process for classical printed circuit boards (PCBs) has been demonstrated.
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Pietraszek, Jacek, Aneta Gądek-Moszczak, and Tomasz Toruński. "Modeling of Errors Counting System for PCB Soldered in the Wave Soldering Technology." Advanced Materials Research 874 (January 2014): 139–43. http://dx.doi.org/10.4028/www.scientific.net/amr.874.139.
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PartnerTech provides printed circuit board (PCB) assembly on request. Wired elements are assembled in through-hole technology and soldered on the wave soldering machine. The PCB with inserted elements is passed across the pumped wave of melted solder. Typically this process is accompanied by some class of defects like cracks, cavities, wrong solder thickness and poor conductor. In PartnerTech Ltd. another type of defects was observed: dispersion of small droplets of solder around holes. Quality assurance department plans to optimize the process in order to reduce the number of defects. In the first stage, it was necessary to develop a methodology for counting defects. This paper presents experimental design and analysis related to this project.
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Tajima, Hikaru, Yuta Nakamura, Yasuyuki Miyazawa, and Hidenobu Tameda. "In Situ Evaluation of the Joining Defects in a Pb-Free Soldered Joint." Materials Science Forum 1016 (January 2021): 1448–53. http://dx.doi.org/10.4028/www.scientific.net/msf.1016.1448.
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Conventionally, brass has toughness more than other metals, so there is a concern about its poor machinability. Therefore, improvement of machinability was attempted by adding lead to brass. This brass called free cutting brass, typified by JIS C3771. This free-cutting brass is used for piping components and machine parts. There is a concern about elution of the lead into drinking water. Hence, Drinking Water Quality Standards Law has been amended and it restricts lead content in the free cutting brass. Therefore, lead-free free-cutting brass with no lead or minimized content of lead is required.Consequently, a lead-free free-cutting brass had been developed to improve in machinability such as JIS C6931 and JIS C6803 that are added Si and Bi instead of lead respectively. Lead was also used for the solder for joining among pure copper pipes and brass valves. That causes elution of lead from the solder into drinking water. For this reason, Lead-free solder such as Sn-Sb and Sn-Ag-Cu have been used.A fire torch technology often was used for soldering of brass. The purpose of this study is investigating soldering-ability and wettability of lead-free solder on lead-free free-cutting brass. Hence, we investigated the soldering ability of lead-free solders, Sn-5%Sb and Sn-3%Ag-0.5%Cu, for pure Cu and brass joints with nonuniform heating by hot plate.
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Yoon, Jeong-Won, Dong-Hwan Lee, and Byung-Suk Lee. "A Study of Transient Liquid Phase Bonding Using an Ag-Sn3.0Ag0.5Cu Hybrid Solder Paste." Journal of Welding and Joining 39, no. 4 (August 30, 2021): 376–83. http://dx.doi.org/10.5781/jwj.2021.39.4.5.
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The feasibility of transient liquid phase (TLP) bonding technology for high-temperature endurable power electronics packaging has been evaluated in this study. An Ag-Sn3.0Ag0.5Cu hybrid solder paste was fabricated and used as a bonding material. The bonding reactions between chip/substrate and hybrid solder paste and die shear strengths of the TLP-bonded joints were evaluated during conventional soldering and vacuum soldering processes. Compared to the conventional soldering, the vacuum-soldered joints had fewer voids and relatively good metallurgical microstructures. After TLP bonding, (Cu,Ni)6Sn5, Ag3Sn, and Cu6Sn5 intermetallic compounds formed at the chip interface, in the middle of the joint, and at the bottom interface, respectively. It was confirmed that the vacuum soldering process could create good interfacial uniformity with minimal voids in the Si chip/ceramic substrate joints. The formation of voids during TLP bonding significantly affected the mechanical shear strength of the TLP-bonded joints. The vacuum-soldered joints had high shear strength values of approximately 40 MPa. To ensure the high joint strength and long-term reliability of Sn-based TLP-bonded joints, critical void control in the joints is needed.
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Atieh, Anas, Tala Abedalaziz, Abdulaziz AlHazaa, Michael Weser, Wael Al-Kouz, Maen Sari, and Ibrahim Alhoweml. "Soldering of Passive Components Using Sn Nanoparticle Reinforced Solder Paste: Influence on Microstructure and Joint Strength." Nanomaterials 9, no. 10 (October 17, 2019): 1478. http://dx.doi.org/10.3390/nano9101478.
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In this study, the effects of adding Sn nanopowder (particle size < 150 nm) to three solder pastes SAC3-X(H)F3+, SCAN-Ge071-XF3+, and water washable WW50-SAC3 are evaluated regarding microstructure, morphology, joint strength, and electrical resistance. The nanopowder was added at a rate of 10% by weight and then mechanically mixed until homogenous solder paste was obtained. The results showed that the addition of Sn nanoparticles resulted in homogenous bond formation for SAC-3 and SCAN, while voids and bubbles formation slightly increased within the joint interface for the water washable solder paste. The SCAN + Sn nano reinforced solder paste showed increased variation of joint strength from 12.6 to 39.9 N, while the water washable + Sn nanopowder reinforced solder paste showed less variability in joint strength from 17.3 to 33.9 N. Both sets of solder paste with and without Sn nano reinforced solder paste showed a reliable quality joint under mechanical shock testing after six shocks in six milliseconds with an 87.1 ms pulse duration. The results showed that Sn nanoparticles resulted in a small resistance change, while RDC values (in mΩ) slightly decreased for SAC and increased for SCAN and further increases for water washable solder paste.
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Ali Mokhtar, Mohd Najib, M. Z. Abdullah, Abdullah Aziz Saad, and Fakhrozi Cheani. "Mechanical reliability of self-aligned chip assembly after reflow soldering process." Soldering & Surface Mount Technology 33, no. 1 (April 13, 2020): 9–17. http://dx.doi.org/10.1108/ssmt-12-2019-0042.
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Purpose This paper focuses on the reliability of the solder joint after the self-alignment phenomenon during reflow soldering. The aim of this study is to analyse the joint quality of the self-alignment assemblies of SnAg alloy solder joints with varying silver content. Design/methodology/approach The shear strength assessment was conducted in accordance with the JIS Z3 198-7 standard. The standard visual inspection of IPC-A-610G was also performed to inspect the self-alignment features of the solder joint samples. Statistical analysis was conducted to determine the probabilistic relationship of shear strength of the misalignment components. Findings The results from the mechanical reliability study indicate that there were decreasing trends in the shear strength value as misalignment offset increased. For shift mode configuration in the range of 0-300 µm, the resulting chip assembly inspection after the reflow process was in line with the IPC-A-610G standard. The statistical analysis shows that the solder type variation was insignificant to the shear strength of the chip resistor. The study concluded that the fracture occurred partially in the termination metallization at the lower part of the chip resistor. The copper content of the joint on that area shows that the crack occurred in the solder joint, and high silver content on the selected zone indicated that the fracture happened partially in the termination structure, as the termination structure of the lead-free chip resistor consists of an inner layer of silver and an outer layer of tin. Practical implications This study’s findings provide valuable guidelines and references to engineers and integrated circuit designers during the reflow soldering process in the microelectronics industry. Originality/value Studies on the effect of component misalignment on joint mechanical reliability are still limited, and studies on solder joint reliability involving the effect of differing contents of silver on varying chip component offset are rarely reported. Thus, this study is important to effectively bridge the research gap and yield appropriate guidelines in the potential industry.