Sintered Silver Interconnects for Traction Inverter Assembly

Abstract:
Thermal resistance of interconnects (die attach, heat-sink attach) and thermal interface material dominate the total thermal resistance of power electronics stacks used in traction inverters. Silver sintering offers a proven technology to overcome the thermal impedance and high temperature stability challenges associated with these power module interconnects. In this paper we present thermal impedance and power cycling results on power modules assembled with silver sintering and solder. Fully sintered IGBT modules (both sintered die attach and top-side attach with a clip) were put through power cycling and benchmarked against comparable commercially available soldered modules. A transient voltage set-up was also used to investigate the thermal impedance of silicon carbide (SiC) die package to inverter heat-spreader attach. The results reveal that by careful selection of the interconnect layers can enhance thermal and reliability of power module stacks significantly.