Impact of wedge wire bonding and thermal mechanical stress on reliability of BPSG/poly layer of a silicon die

In this paper, the impact from both mechanical and thermal effects, with different parameters on BPSG of a power package is studied. The impact parameters include wedge wire bonding force, clamping force from the spring clip, wave soldering process and power dissipation from the die. An advanced 3D FEA model framework with a global model and local sub-model is developed. Major modeling work includes two areas: One is to evaluate the impact of the wire bonding force during the wedge bonding assembly process and the clamping force from the spring clip. Another area is to study the thermal stress due to thermal expansion mismatch which includes the wave soldering process and power dissipation. Both the global and sub-model simulation results have shown that the stress distribution in BPSG due to the wire bonding process, spring clip clamping force, wave soldering and power dissipation. The modeling has disclosed that the impact of thermal stress is greater than that of wedge wire bonding process and spring clip clamping force.