Study of shear locking effect on 3D solder joint reliability analysis

Abstract The fabrication process of WLP (wafer-level packaging) has become more mature, and using the finite element method (FEM) to predict reliability life electronic packaging can shorten design cycles. This study adopted NSMD (non-solder mask defined) solder joint structure in used an energy geometry. A fixed mesh size will be determined for critical region evaluate inelastic strain due thermal loading analysis. However, under influence geometry some tested vehicles, especially when contact angle lower pad is less than 20 degrees, a shear locking phenomenon occur at joint. causes abnormal transfer. excessive concentrated on upper part joint, resulting incorrect estimation life. Reduced integration prevent improved results compared full integration. this research demonstrate that FEM proper control reduced point regions deliver accurate prediction WLP.