Thermal Shock Life Prediction of the SiC Wide Bandgap Power Module Semiconductor Package Considering Creep Behavior of the Ag Sintered Interconnect and Viscoelastic Properties of the Epoxy Molding Compound

Abstract

In this study, the thermal shock life cycle of a wide bandgap (WBG) power module was predicted using finite element analysis considering the thermal fatigue/creep deformation of Ag sintered joints and the viscoelastic properties of epoxy molding compounds (EMCs) under periodic thermal shock conditions. To analyze the thermomechanical behaviors of the WBG power module, creep tests were carried out under continuous shear loading to evaluate the creep properties of Ag sintered joints depending on the temperature and shear stress. Also, the viscoelastic properties of fully cured EMCs were measured by conducting three-point bending stress relaxation tests. The stress/strain distributions of the power module package during the thermal shock cycles were predicted. Finally, the failure life cycle of the Ag sintered joints was calculated using the total strain–life equation based on the results of the thermal fatigue experiments. Thermal shock tests of the manufactured WBG power module were conducted to confirm the thermal fatigue cycle at which the Ag sintered joints began to be damaged. It was concluded that the failure life cycle of Ag sintered joints could be accurately predicted using the finite element (FE) simulations considering the creep and thermal fatigue properties of the Ag interconnect and the viscoelastic behavior of EMCs.