Solder joint reliability is one of critical problems detemining whether Sirface Mount Technology (SMT) can be used in the prohotion of important electronic products. Optimizing solder joint shape is one of effective ...Solder joint reliability is one of critical problems detemining whether Sirface Mount Technology (SMT) can be used in the prohotion of important electronic products. Optimizing solder joint shape is one of effective ways to improve SMT solder joint reliability.In this paper. based on the theorem of minimum potential energy, an energy model of 3 - D solder joint shape is established,and the forma- tion of solder joint is numerically simulated by Surface Ecolver program. On the basis of the prediction of SMT solder joint shape,the mechanical model of analyzing solder joint reliability is established. An elasto - plasto - creep mateial model and its mechanical constitutive equaton are established for SnPb solder alloy, and the stress/strain response of SMT solder joint under thermal cyclical loabing is ana- lyzed with nonlinear 3 - D FEM. The fatigue life of solder joint is predicted according to Coffin- Manson fatigue life model. An integrated system for Predicting and analyzing SMT solder joint shape and reliability(PSAR) is developed.The system can analyze efficiently SMT solder joint reliability with the variation of structural parameters in the joint and give the optimal structure.展开更多
A visual software system has been developed for predicting and analyzing the shape of solder joints in surface mount technology (SMT). The formation of the solder joint is numerically simulated through Surface Evolver...A visual software system has been developed for predicting and analyzing the shape of solder joints in surface mount technology (SMT). The formation of the solder joint is numerically simulated through Surface Evolver program and the calculation is automated with an additional controller. A preprocessor is developed in which process parameters determining the shape of solder joints can be input visually and transferred into Evolver program automatically. A postprocessor is built to analyze the global three dimensional shape and cross section profiles of solder fillets in multiple windows. Also, the application for predicting the solder joint shape of RC chip component is conducted with the PSJS system.展开更多
The solder joint reliability of a 0.5mm 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 plas...The solder joint reliability of a 0.5mm 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 1.25mm×0.35mm, the stand-off of 0.02mm and the solder volume of 0.026mm^3 has longer fatigue life than that of any others. These optimal parameters have been applied in practice to assemble the 240-pin, 0.5mm pitch QFP.展开更多
The geometry of solder joint in SMT is one of the important factors whichdetermine the solder joint reliability. In this study, a type of solder joint specimen has beendesigned and is subjected to thermal cycling to f...The geometry of solder joint in SMT is one of the important factors whichdetermine the solder joint reliability. In this study, a type of solder joint specimen has beendesigned and is subjected to thermal cycling to failure between -55 ℃ to +125 ℃ with a 36℃/min heating and cooling rate and 10 min temperature holding times. The solder jointgeometry is castellated and controlled with different solder fillet shape and stand off height.A statistical analysis of the scattered thermal cycle lives of solder joints by two parameterWeibull's probability density function has been carried out in this paper. The experimentalresults show that the more reliable solder joint geometry has flat or slight convex solderfillet with a stand off height larger than 0.1 mm. The results may be the recommendedguideline to design optimal solder joint geometry.展开更多
A finite element analysis for calculating three-dimensional(3-D) solder joint shape between chip component and substrate pad was carried out, and the effects of solder volume and pad extension beyond the edge of compo...A finite element analysis for calculating three-dimensional(3-D) solder joint shape between chip component and substrate pad was carried out, and the effects of solder volume and pad extension beyond the edge of component on solder joint shapes were investigated. The resonable design ranges of solder volume and pad extension have been put forward.展开更多
深入分析了航天电子产品中表面组装技术(surface mount technology,简称SMT)焊点可靠性影响因素及失效机理,研究了温度循环下SMT焊点弹塑性应力应变规律及其寿命预测方法,并在此基础上探索了元件与焊盘间隙、钎料量、外轮廓等形态对焊...深入分析了航天电子产品中表面组装技术(surface mount technology,简称SMT)焊点可靠性影响因素及失效机理,研究了温度循环下SMT焊点弹塑性应力应变规律及其寿命预测方法,并在此基础上探索了元件与焊盘间隙、钎料量、外轮廓等形态对焊点热疲劳寿命的影响,揭示焊点形态与应力应变和疲劳寿命之间的对应关系,以寻求具有较为理想力学性能及热循环寿命的焊点形态.结果表明,上述理论方法为实际焊接过程中的PCB上焊盘尺寸的合理设计提供了理论支撑.展开更多
文摘Solder joint reliability is one of critical problems detemining whether Sirface Mount Technology (SMT) can be used in the prohotion of important electronic products. Optimizing solder joint shape is one of effective ways to improve SMT solder joint reliability.In this paper. based on the theorem of minimum potential energy, an energy model of 3 - D solder joint shape is established,and the forma- tion of solder joint is numerically simulated by Surface Ecolver program. On the basis of the prediction of SMT solder joint shape,the mechanical model of analyzing solder joint reliability is established. An elasto - plasto - creep mateial model and its mechanical constitutive equaton are established for SnPb solder alloy, and the stress/strain response of SMT solder joint under thermal cyclical loabing is ana- lyzed with nonlinear 3 - D FEM. The fatigue life of solder joint is predicted according to Coffin- Manson fatigue life model. An integrated system for Predicting and analyzing SMT solder joint shape and reliability(PSAR) is developed.The system can analyze efficiently SMT solder joint reliability with the variation of structural parameters in the joint and give the optimal structure.
文摘A visual software system has been developed for predicting and analyzing the shape of solder joints in surface mount technology (SMT). The formation of the solder joint is numerically simulated through Surface Evolver program and the calculation is automated with an additional controller. A preprocessor is developed in which process parameters determining the shape of solder joints can be input visually and transferred into Evolver program automatically. A postprocessor is built to analyze the global three dimensional shape and cross section profiles of solder fillets in multiple windows. Also, the application for predicting the solder joint shape of RC chip component is conducted with the PSJS system.
基金Project(02336060) supported by the Natural Science Foundation of Guangxi Province , China
文摘The solder joint reliability of a 0.5mm 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 1.25mm×0.35mm, the stand-off of 0.02mm and the solder volume of 0.026mm^3 has longer fatigue life than that of any others. These optimal parameters have been applied in practice to assemble the 240-pin, 0.5mm pitch QFP.
文摘The geometry of solder joint in SMT is one of the important factors whichdetermine the solder joint reliability. In this study, a type of solder joint specimen has beendesigned and is subjected to thermal cycling to failure between -55 ℃ to +125 ℃ with a 36℃/min heating and cooling rate and 10 min temperature holding times. The solder jointgeometry is castellated and controlled with different solder fillet shape and stand off height.A statistical analysis of the scattered thermal cycle lives of solder joints by two parameterWeibull's probability density function has been carried out in this paper. The experimentalresults show that the more reliable solder joint geometry has flat or slight convex solderfillet with a stand off height larger than 0.1 mm. The results may be the recommendedguideline to design optimal solder joint geometry.
文摘A finite element analysis for calculating three-dimensional(3-D) solder joint shape between chip component and substrate pad was carried out, and the effects of solder volume and pad extension beyond the edge of component on solder joint shapes were investigated. The resonable design ranges of solder volume and pad extension have been put forward.
文摘深入分析了航天电子产品中表面组装技术(surface mount technology,简称SMT)焊点可靠性影响因素及失效机理,研究了温度循环下SMT焊点弹塑性应力应变规律及其寿命预测方法,并在此基础上探索了元件与焊盘间隙、钎料量、外轮廓等形态对焊点热疲劳寿命的影响,揭示焊点形态与应力应变和疲劳寿命之间的对应关系,以寻求具有较为理想力学性能及热循环寿命的焊点形态.结果表明,上述理论方法为实际焊接过程中的PCB上焊盘尺寸的合理设计提供了理论支撑.
