3.3 kV 800 A IGBT Module with High Power Cycle Durability Fulfilling Roll2Rail Target

Abstract:
Last year we presented the dramatic improvement of power-cycling durability of an IGBT module by adopting Cu-sintered die attach, which realized the Roll2Rail target power-cycling durability. In this presentation, we review the physical analysis results at the end of module life. Whilst the damage in the Cu sintering layer and the wire bond were marginal, the deterioration at the base plate and heat sink interfaces were more severe in the TIM, followed by the substrate solder layer. Whilst Tc increased with the deterioration of the TIM layer, it was not assessed to cause the critical degradation of the substrate solder. Instead of an initial assessment using modified Coffin-Manson with the temperature parameter of Tc, we propose a prediction method using the estimated temperature of the substrate as a new parameter. The test results verified the accuracy of the predictive methodology and exhibited consistency with the degree of deterioration.