Thermo-mechanical Characterization and Stress Simulation of Epoxy Molding Compound for a High-Power Package with Silicon Nitride Passivation Layer

In this paper, the influence of epoxy molding compound thermomechanical material properties on die top silicon nitride passivation stress during temperature cycling on a high-power surface mount device was studied. The combination of EMC properties (Tg, CTE, and modulus) using different advanced EMCs to achieve lower tensile stress on SiN passivation layer for a high-power SMD was successfully investigated through material characterization, assembly and delamination performance, thermo-mechanical stress simulation, reliability testing, and passivation layer integrity check after TCT. Furthermore, stress relief mechanism related to the mold compound property was proposed based on the results of the study.