A Thermo-Mechanical Fatigue Damage Modeling Methodology for Power Semiconductor Robustness Validation Studies

A numerical approach to model fatigue damage propagation in metal-on-silicon structures under transient thermal loading is presented. The considered fatigue failure mechanisms are fatigue crack growth inside the thick metallization and potential cyclic delamination growth at the interface between the metallization and the silicon. Advanced methods within the framework of the Finite Element Method are developed to study these failure mechanisms and to assess the material and interface degradation on a generic metal-onsilicon geometry. Such methodology can be applied to explore fatigue-determined robustness limits of power semiconductor devices exposed to severe temperature swings, e.g. during cyclic electric overload switching.