Influence of Thermal Parameters on Packaging Reliability of SiC MOSFETs

Silicon Carbide (SiC) Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) are increasingly adopted in electric vehicle applications due to their wide bandgap, high breakdown voltage, elevated switching frequency, and excellent thermal conductivity. However, traditional packaging structures limit their reliability, especially under thermal cycling stresses that induce failures in bonding wires and solder joints. This study utilizes finite element simulation to investigate thermo-mechanical behaviors in SiC MOSFET packaging. A calibrated threedimensional model, based on transient thermal impedance measurements, simulates stress and strain distributions under varying temperature conditions. The analysis elucidates mechanisms of temperature-induced bonding wire failure and solder joint aging, while evaluating five key factors: junction temperature swing (Δ T), mean junction temperature(T_m), heating rate (R), high-temperature holding time (t), and cooling rate (Rc).Findings demonstrate that larger Δ T and higher Tm significantly amplify plastic strain accumulation, accelerating interfacial degradation and thermal fatigue. Increased R and prolonged t further promote packaging deterioration, whereas R has minimal impact.