Long-Term High-Temperature Storage of Liquid-Metal Interconnects on SiC MOSFETs

This paper investigates the high-temperature performance of liquid-metal packaged SiC MOSFET power modules, in which all critical interconnects (die-attach, topside, and gate connections) are implemented using a Gallium-based liquid-metal paste. The modules are evaluated under high-temperature storage (HTS) at 125 °C for 1000 hours. The on-state resistance and thermal impedance are measured before and after storage and compared with conventional wire-bonded modules subjected to the same test conditions. Three samples of each packaging style are assessed. The results show that the liquid-metal interconnects preserved electrical functionality throughout the test, however, a significant degradation in thermal impedance was observed. Conversely, wirebonded modules showed noticeable on-resistance degradation, while the thermal impedance remained stable. X-ray inspection suggests a reduced amount of liquid metal remaining at the interfaces, indicating possible diffusion of the liquid-metal into surface metallization and a reduction in the available liquid-metal thermal contact area. Additionally, any resulting intermetallic compounds may have differing electrical and thermal characteristics. Contamination of the liquid-metal interfaces from discharge from other components within the module is also a possible explanation for performance degradation.

Hali tarjima qilinmagan