In this article, the random vibration test and finite-element simulation analysis of SAC305 solder joints in BGA packaged electronic chips were carried out. A failure model for BGA solder joints was established based on the life data. And vulnerable parts in electronic chips were analyzed. First, the random vibration test was conducted. Second, a lognormal distribution model of solder joints by means of the life data was established and analyzed based on the fracture mechanics theory. Finally, the finite-element simulation model of BGA packaged electronic chip was established and discussed. Failure characteristics of solder joints at different positions in electronic chips were compared and the failure mode of the solder joint was discussed using the simulation result and the observation result with scanning electron microscope (SEM). The results show that the life of each single solder joint in BGA packaged electronic chips follows a logarithmic normal distribution under the random vibration. Solder balls located at the four outermost corners of the chip are subjected to the greatest stress, which are the weakest parts in electronic chips. Cracks in solder joints are generated near the package side and emerged from the edge of the intermetallic compound (IMC) layer with the largest curvature.

中文翻译：

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BGA封装电子芯片中焊点的失效分析和建模

本文对BGA封装的电子芯片中SAC305焊点进行了随机振动测试和有限元模拟分析。基于寿命数据，建立了BGA焊点的失效模型。并对电子芯片中的易损部件进行了分析。首先，进行随机振动测试。其次，基于断裂力学理论建立并分析了基于寿命数据的焊点对数正态分布模型。最后，建立并讨论了BGA封装电子芯片的有限元仿真模型。比较了电子芯片中不同位置焊点的失效特性，并利用仿真结果和扫描电子显微镜（SEM）的观察结果讨论了焊点的失效模式。结果表明，在随机振动下，BGA封装的电子芯片中每个单个焊点的寿命遵循对数正态分布。位于芯片最外四个角的焊球承受的应力最大，这是电子芯片中最薄弱的部分。焊点的裂纹在封装侧附近产生，并从曲率最大的金属间化合物（IMC）层的边缘出现。