Fatigue life prediction for solder interconnects in IGBT modules by using the successive initiation method

Insulated gate bipolar transistors are the power semiconductors used for high current applications as a switching device. It is widely used in electrical and hybrid vehicles. It has become increasingly important to understand the reliability of these modules. The lifetime prediction is based on the assumption that the solder interconnections are the weakest part of the module assembly and that the failure cause is the inelastic deformation energy accumulated within the solder material. In this paper, the effects of thermal fatigue of the solder layer interface have been investigated. A 2D model of 6 pack, 1200V IGBT module is used for the analysis. This study presents simulation of crack initiation and propagation under thermo-mechanical loading. Successive initiation technique is used to propagate crack in solder layer. A cyclic creep-fatigue damage under thermal loading is modeled using Energy Partitioning model to predict the fatigue life of an IGBT module.