Design and Fabrication of a Ceramic Substrate-Embedded SiC Power Module

Embedded packaging of wide-bandgap (WBG) power modules offers an inherently lower parasitic inductance, higher switching frequency, and lower power losses compared to traditional wire-bonding technology. However, the present embedded technology suffers from a relatively tight laser drilling process window and unknown reliability. This work presents a new embedded packaging technology with minimal thermomechanical interfacial stress and a relaxed process window. For this purpose, a presintered die top system (DTS) layer for an improved laser drilling process window with minimal interfacial stress in the topside interconnection is adopted. To design and fabricate the proposed new embedded power module, the interaction between different ceramics and the lamination resin is also studied. Furthermore, the thermal and thermomechanical stress characteristics of the proposed embedded, conventional embedded, and wire-bonded power modules have been analyzed and compared through FEM multiphysics simulations to evaluate the performance of the three packaging approaches. The simulations indicate that despite the maximum von Mises stress of silicon nitride (Si3N4) is the highest compared to its substrate counterparts, the obtained maximum stress is much lower than its flexural strength and thus is the best choice of the substrate material. The silicon-carbide (SiC) module prototypes fabricated based on the proposed embedding technique show a good laser drilling performance, resulting in excellent plating quality. In addition, our fabrication results show good agreement with the out-of-plane deformation simulation results. Finally, the proposed module exhibits good reproducibility and process stability due to the protection of the DTS layer.