Electro-Thermo-Mechanical Simulation Analysis Of Multichip SiC MOSFET Power Modules

Compared to the traditional single-sided cooling (SSC) power module, the double-sided cooling (DSC) power module has become a rapidly growing research field in the electric vehicle (EV) sector. However, current sharing and thermal coupling issues among multichip modules are still big challenges in the double-sided cooling silicon carbide (SiC) MOSFET power module. In this paper, a new multichip Flip chip double-sided cooling modules (FCDSC) design scheme is proposed. The design incorporates the Gate-free wire and all-sintered silver method to fabricate the module, while the module spacer is made of CuMo material. In a simple straight layout, the distance between adjacent dies is large enough to avoid heat concentration and junction temperature differences resulting from the thermal coupling effect. Thermal, electrical, and mechanical properties of the multichip FCDSC power module were analyzed from the aspects of electrothermal coupling, under different power losses, temperatures, and temperature cycling, and electrical test. The multichip FCDSC modules have a better heat dissipation effect than the conventional modules and the thermo-mechanical stresses caused by the mismatch of the coefficients of thermal expansion (CTE) are lower and the parasitic inductance of the modules has been reduced, achieved a notable reduction of 12% in current imbalance, ensuring impressive current equalization.