Abstract Due to the increasing miniaturization of microelectronic packaging, the electromigration (EM) phenomenon generally exists in microscale lead-free solder joints, which is mainly caused by high current stressing. To address the limitation of experimental measurement at a microscale, this study performed a finite element analysis (FEA) based on microstructure simulation and image recognition to characterize the influence of microstructure inhomogeneity on the magnitude and distribution of current density and temperature gradient in microscale line-type Sn58Bi solder joints under current stressing. The simulation results indicate that the microstructure inhomogeneity has a significant influence on the magnitude and distribution of the current density and temperature gradient in Sn58Bi solder joints. Specifically, the current density and the total current-induced Joule heats in the Sn-rich phase are much higher than those in the Bi-rich phase. However, the temperature gradient in the Sn-rich phase is smaller than that in the Bi-rich phase. Moreover, similar results and conclusions can be obtained from both two- and three-dimensional FEA.

中文翻译：

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电流应力下微观结构不均匀性对微尺度线型Sn58Bi焊点电流密度和温度梯度的影响

摘要 由于微电子封装越来越小型化，微尺度无铅焊点普遍存在电迁移（EM）现象，主要是由大电流应力引起的。为了解决微尺度实验测量的局限性，本研究进行了基于微观结构模拟和图像识别的有限元分析（FEA），以表征微观结构不均匀性对微尺度线中电流密度和温度梯度的大小和分布的影响 - Sn58Bi 型焊点在电流应力下。仿真结果表明，微观结构的不均匀性对 Sn58Bi 焊点中电流密度和温度梯度的大小和分布有显着影响。具体来说，富锡相中的电流密度和总电流感应焦耳热远高于富铋相。然而，富锡相的温度梯度小于富铋相。此外，从二维和三维有限元分析中可以获得类似的结果和结论。