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针对封装体叠层中的堆叠焊球进行了有限元建模和应力分析,评估了TMV堆叠焊球这种新型焊接方式可能带来的可靠性隐患。通过仿真结果发现,堆叠焊球的应力集中比底部焊球更加严重,这说明热疲劳失效更容易发生在塑封胶穿孔中的堆叠焊球上,而原本针对底部焊球的可靠性测试标准则需要做出新的调整。此外,在两种不同的堆叠焊球成型中,雪人式焊球的应力集中比较水桶状焊球更加严重。通过参数研究可以发现,紧缩区域的宽窄程度是造成雪人式焊球应力集中的关键因素。
Finite element modeling and stress analysis of the stacked balls in the package stack were carried out to evaluate the possible reliability risks of the new type of welding with TMV stacked balls. The simulation results show that the stress concentration of the stacked balls is more serious than that of the bottom ones, which indicates that the thermal fatigue failure is more likely to occur on the stacked balls in the plastic perforations, whereas the reliability testing standards originally required for the bottom balls require Make new adjustments. In addition, snowball-type solder balls tend to have more concentrated stress than bucket-shaped solder balls in two different stacked ball shapes. Through the parameter study, it can be found that the width and width of the constricted area are the key factors that cause the stress concentration of snowman-type solder balls.