Prediction of the fatigue life in lead-free solder bump and application to the area-array package

为了预测无铅微电子焊点的裂纹扩展寿命，提出了一种新的裂纹扩展分析方案——任意线法和有限元法程序。并获得了一些实际应用所需的实验数据。综上所述，裂纹扩展速率的相关数据起着关键作用，并且是根据最大开启应力范围获得的。用该方法计算的裂纹扩展寿命与实验值吻合较好。这同时表明，无铅微电子焊点的裂纹扩展速度和路径是可以通过在距离裂纹尖端一定径向距离处测量的最大开口应力范围来控制的。

In order to predict the crack growth life in lead-free microelectronics solder joints, method of arbitrary lines and finite element method program employing a new scheme for crack growth analysis are developed. Also some experimental data necessary for the practical application of this program are obtained. Above all, the data related to the crack growth rate play a key role and are obtained in terms of the maximum opening stress range. The calculated values of the crack growth life by the proposed method are in good agreement with the experimental ones. This indicates at the same time that the crack growth rate and path in lead-free microelectronics solder joints are certainly controlled, through the maximum opening stress range measured at a certain radial distance from the crack tip.