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中的裂纹扩展寿命，采用一种新的裂纹扩展分析方法，开发了任意直线法和有限元程序。同时也得到了该程序实际应用所需的一些实验数据。最重要的是，与裂纹扩展速率相关的数据起着关键作用，并且是根据最大张开应力范围获得的。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，在无铅微电子焊点中的裂纹扩展速率和路径肯定是受控的，通过在一定的径向距离从裂纹尖端测量的最大张开应力范围。

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.