Simulation and testing for drop impact reliability of 3D eWLP

In this paper, the drop impact reliability of the 3D embedded wafer level package (eWLP) was studied by the experiment and finite element simulation. The drop impact reliability test of the 3D eWLP test vehicle was conducted under the loading of 1500 g within 0.5 ms. The failure mechanisms were identified through the failure analysis experiment. The experimental results show that the failure modes are the delamination at the interface between the dielectric layer and Cu pad and at the interface between the dielectric layer and die/epoxy molding compound (EMC) under the drop impact loading. The stress and strain behaviors of the solder ball and dielectric layer of the 3D eWLP were investigated by the finite element simulation. The simulation results show that the high level of peeling stresses happen to the dielectric layer under critical corner solder joint near the die edge and package edge of the bottom package which caused the delamination failures.