Power Cycling Reliability and Failure Modes in Power Modules with Novel Emitter Contact and Sintering Technologies

Abstract:
Power semiconductor modules undergo extreme thermal excursions, which require reliable joining connections for emitter contact and die bond. Due to new technologies like wide-bandgap devices with higher operation temperature as well as enhanced customer requirements for traction and automotive applications, the standard packaging technologies like soldering and aluminum wire bonding need to be replaced with novel joining technologies. In this work, the power cycling reliability of IGBT power modules was investigated, where the emitter contact was connected by novel bond wires or a top plate combined with copper bond wires in combination with sintering techniques for die bond. The results were compared with references having conventional solder and standard aluminum wires. A significant increase in power cycling capability was achieved by replacing soldering with sintering and using novel bond wires. Surprisingly, no improvement was achieved by top emitter plate and copper wire bonding due to a new failure mode related to delamination between chip surface and top emitter plate. This paper provides a deep dive in understanding of the observed failure mode, root causes and possible solutions.