Thermal-mechanical-electrical Co-design of Fan-Out Panel-Level SiC MOSFET Packaging with a Multi-objective Optimization Algorithm

Abstract

As the next generation of semiconductor devices, SiC MOSFETs have demonstrated significant performance improvements in switching loss, switching frequency, and hightemperature operation compared to Si-based MOSFETs. However, the long-term reliability of such devices and their packaging continues to be a major concern. Towards addressing this challenge, this study proposes a multi-objective optimization design method for parasitic inductance (L), thermal strain (ε), and thermal resistance (R) of SiC MOSFETs with Fan-Out Panel-Level Packaging (FOPLP). First, the orthogonal experimental design was employed to investigate the thickness effects of baseplate, solder, die and redistribution layer (RDL) on L, ε, and R. Then, the multiobjective optimization was developed to simultaneously reduce L, ε, and R. Finally, the fatigue lifetimes of the optimized and initial SiC MOSFET FOPLP structures were compared to verify the optimization's accuracy. Study findings include: (1) Solder thickness was the most significant influence factor for L, ε and R of SiC MOSFET FOPLP, L and R increased, and ε decreased with increasing solder thickness; (2) The proposed multi-objective optimization method coupled with a genetic algorithm achieved 14.79, 8.96, and 9.28% reduction of L, ε, and R, respectively; (3) The fatigue lifetime of solder (SAC305) was evaluated using the Coffin-Manson model, with predicted lifetimes before and after optimization being 6786 and 7085 cycles, respectively, demonstrating that the proposed approach significantly enhanced the designed SiC MOSFET FOPLP's long-term thermal cycling reliability.