Insulated gate bipolar transistor (IGBT) is widely needed in many applications, such as motors, inverters, express railways, and automobiles. As the integrity level of IGBT increases, thermal management becomes a more significant issue, especially when third-generation semiconductor chips made with SiC or GaN come into application. Here, a press packaging SiC IGBT module is designed, which involves silver sintering. Firstly, we make a thermal analysis using the finite element method (FEM). Then, a heat dissipation plane is optimized. Groups of heat sink materials and airflow velocities are investigated, and an optimized one is chosen as the basis of further fatigue analysis. In the simulated working condition, the maximum temperature can reach 100°C, which could further induce serious problems in fatigue performance. We have analyzed 4 models with different silver layer edge shapes. The best one shows a 27% higher expected fatigue life than the standard one, which shows that the fatigue performance is very sensitive to the edge shape of the silver layer. This research can help further optimization and designing of advanced IGBT devices.