Power cycling reliability of IGBT power modules

The goal of this study was to understand the power cycling reliability of IGBT power modules. These power modules are made up of multi-layer stacks and consist of multiple power dice in parallel. The interconnection schemes within the module include leadframes soldered to substrate, die attachment using solder and wirebonds. Thermal and power cycling fatigues material interfaces because of the CTE mismatch between dissimilar materials. In addition, wirebonds on the dice are prone to debonding because of the thermally induced stresses. Tests were designed to understand the power cycling reliability of these large transistor modules. Results from the tests are summarized in this paper.