Direct Integration of Optimized Phase-Change Heat Spreaders Into SiC Power Module for Thermal Performance Improvements Under High Heat Flux

Silicon carbide (SiC) power modules are attractive in many applications due to the superiority of their semiconductor characteristics. However, power modules are subjected to repetitive thermo-mechanical stress caused by the mismatch of the coefficient of thermal expansion between different layers of materials. Moreover, the relatively smaller die size of SiC chips makes the heat flux increase significantly, which brings new challenges to the thermal management and reliability of SiC power modules. To tackle these challenges, this article proposes a new thermal enhanced packaging method based on vapor chamber (VC) phase change heat spreader (PCHS) for SiC power modules, achieving the advantages of high thermal conductivity, low weight, low cost, and low thermal stress. In this new design, SiC mosfet bare dies are directly soldered on the top of VC-PCHS, which not only act as heat spreaders but also conduct the drain current of mosfets. The integrated VC-PCHS is optimized based on thermal and thermomechanical performance. An SiC power module prototype directly integrated with VC-PCHS is built using a new fabrication process. Both the simulations and experiments demonstrate significant improvements in thermal and thermomechanical performance. The modules integrated with VC-PCHS can operate under 200 W of power dissipation per die (632 W/cm(2)) without exceeding the maximum rated junction temperature. This article reveals the potential of directly integrating phase change cooling components inside power modules, providing a new solution to improve the thermal performance and reliability of SiC power modules without adding complexity and energy consumptions to external cooling systems.