Failure mechanism evolution of bond wires and solder layer under various thermal coupling effects

Failure mechanism analysis is crucial Reliability assessment for power modules and has garnered increasing attention. In multichip modules, complex failure modes caused by thermal coupling effects (TCEs) pose a significant challenge to clarifying failure mechanisms. This study, therefore, analyzes the competitive failure mechanisms of bond wires and solder layers, considering different TCEs produced by varying load current durations (ton) and chip-to-chip distances (xchip). The TCEs' influence on failure modes is first evaluated experimentally. Subsequently, based on the mechanisms of TCEs, the conditional parameters that may affect them are analyzed. Furthermore, with the assistance of a finite element model, the evolution of failure mechanisms under different TCEs caused by various ton and xchip is revealed. The results indicate that the effect of TCEs on failure differs under various ton and xchip conditions. A decrease in xchip increases the solder layer's failure risk during TCE tests, whereas an increase in ton elevates the failure risk for bond wires.