Balanced Vertical Structures for Thermal Expansion Matching and Reduced Thermomechanical Stress in Silicon Carbide Double-Sided Cooling Power Modules

Double-sided cooling (DSC) power modules are widely used in xEV applications. However, conventional DSC modules experience significant thermomechanical stress at the bonding layers due to asymmetry in top/bottom heat dissipation and differences in the coefficients of thermal expansion (CTEs) among DSC components. These stress-induced challenges are more pronounced in silicon carbide (SiC) devices, which have a larger Young’s modulus than silicon-based devices. To address these challenges, this study re-evaluates the vertical DSC stacking structure after introducing an additional bottom spacer between the die and bottom substrate. Various vertical structural and material configurations are rigorously analyzed using a newly defined design objective, the thermal expansion ratio, which comprehensively reflects both thermal and structural characteristics, offering a more accurate representati…