Comparative Analysis of Bond Wire Degradation in Power Modules During DC and AC Power Cycling

This study assesses bond wire degradation differences between DC and AC power cycling tests in IGBT power modules. With existing experimental data, an empirical lifetime model has been developed for both methods. With the bond wire lift-off being the main failure mechanism, physical modeling approach is applied using a simplified thermo-mechanical finite element model to examine the temperature evolution, stress and strain development at the bond wire-chip interface. Factors including heating time, temperature gradient, and current density are addressed and discussed to explain the number of cycles to failure difference between the two power cycling test methods.