Model for Power Cycling lifetime of IGBT Modules - various factors influencing lifetime

A large number of power cycling data from different IGBT module generations and test conditions have been evaluated. Multiple regression with respect to the variables temperature swing DeltaTJ, TJ, power-on-time (ton), chip thickness, bonding technology, diameter (D) of bonding wire, current per wire bond (I) and package type was performed. It provided parameters for a new empirical model describing number of power cycles (Nf) in relation to these variables. For a fixed module technology and blocking voltage class, the set of variables have been restricted to DeltaTJ, TJ, ton and I as the factors influencing the number of cycles to failure. The model is used to estimate the power cycling capability for the new generation of 1200V-IGBT4 Modules, which are rated up to a junction temperature of 150deg C in operation.