Chip Area Impact on Power Cycling Lifetime of IGBT Modules

Inhalt:
For lifetime prediction of power electronic modules the area related temperature average is incorporated in established lifetime models. Degradation processes, however, are rather sensitive to gradients of temperature and stress evolving during power cycling. Against this background the question arises, if the variation of chip area in the same module architecture has an impact on the lifetime. In the present study the lifetime of power modules assembled with IGBTs of varying area is compared in power cycling tests with different load pulse durations. The experimental results show that the impact of chip size on power cycling lifetime is insignificant. FEM simulations of the test structures provide evidence for the observed differences in solder fatigue for different load pulse durations.