Miniaturized Double Side Cooling Packaging for High Power 3 Phase SiC Inverter Module with Junction Temperature over 220 °C

In this paper, authors developed miniaturized double side cooling packaging for SiC (silicon carbide) high power inverter module using new material solutions to withstand high temperature condition over 220 degrees C. Instead of conventional thick wire bonding on the device, the flip chip bonding for high power source and gate interconnections are developed. For the drain interconnection, copper clips are attached using high temperature endurable interconnection materials. By utilizing these flip-chip structures, the power module with double side cooling design was enabled effectively for the heat dissipation induced by high power switching operation. Through the thermal modeling and characterization, the power module's package thermal dissipation performance was found to be enhanced by 2 times compared with the conventional single side cooling type power module. To cope with the increased maximum junction temperature limit to operate wide band gap power devices the novel packaging material and its process which can endure up to 220 degrees C were developed also. Bi and Ag based high temperature solder was applied for the flip-chip bumping for SiC device on the DBC (direct bonded copper). The copper clip was applied on the device backside as drain interconnection to DBC also. High temperature endurable EMC (epoxy molding compound) and TIM (thermal interface material) were also evaluated. The packaging process was optimized and developed along with the modeling. Through the reliability assessment, we could show the potential applicability of double side cooling power module with flip-chip and clip bonding design and it would be useful for the SiC and GaN based high power module and high junction and environmental temperature endurable applications for the near future.