To improve the thermal reliability of BGA solder joints with dual-side molding,the stress-strain distribution and fatigue life of BGA solder joints were analyzed under temperature cyclic loading by finite element analysis and the Darveaux fatigue life model.Based on Taguchi experiments,the effect of the height and thermal expansion coefficient of the upper and lower layers of molding compound was studied on the reliability of the BGA solder joints,and the fatigue life was further optimized for the solder joints.Finally,the effect of the size of the lower layers of the molding compound was further studied and optimized on the thermal fatigue life of the solder joints.The results show that the smaller the height and thermal expansion coefficient of the upper and lower layers of the molding compound,the higher the fatigue life of the solder joints.The coverage of the BGA solder joints by the lower layer of the molding compound is not conducive to the thermal reliability of the solder joints.After two optimization steps,the fatigue life of the solder joints is 177 cycles,which is 5.71 times that before optimization.
关键词
双面塑封/温度循环/有限元分析/疲劳寿命/田口试验
Key words
dual-side molding/temperature cycle/finite element analysis/fatigue life/Taguchi experiment
维普
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