New industrial module package with matched CTE materials

Abstract

A novel IGBT module construction using materials with matching coefficients of thermal expansion (CTEs) to provide longer lifetime and increased reliability will be presented. This technology reduces the stress on solder layers in the module, which tend to fatigue due to the module's flex during heat cycle tests. It will be shown that designs with matching CTEs also reduce the module's susceptibility to the migration of thermal grease from the gap between the module and the heatsink, a phenomenon referred to as pump-out. Pump-out creates potential failure points due to large resistances in the thermal path created by the resulting air gaps. Test results will be presented which show that the new module using matching CTE construction can provide upwards of seven times greater thermal cycle life than conventional modules based on DBC ceramic construction.