Press-pack insulated gate bipolar transistors (IGBTs) demonstrate significant advantages including high power density, double-sided cooling capability, low thermal resistance, and short-circuit failure characteristics, making them widely adopted in flexible DC transmission systems. Given the requirement for these devices to withstand occasional short-circuit current impacts in such applications, enhancing their short-circuit withstand capability (SCWC) constitutes a critical requirement for ensuring secure and reliable operation of flexible DC transmission systems. In this paper, an electro-thermal-mechanical multi-physics coupling model for press-pack IGBTs based on short-circuit failure experimental data is established and the electro-thermal-mechanical distribution patterns across IGBT chip surfaces under microsecond-level short-circuit conditions are analyzed, revealing that electro-thermal-mechanical stress is most concentrated at the edge of the active region. To address the stress concentration at the active region edge and the weak short-circuit withstand capability, a study was conducted on the impact of silver sintered packaging optimization on short-circuit withstand capability. Comparative analysis of electro-thermal-mechanical distribution before and after optimization reveals that silver sintered packaging significantly improves short-circuit withstand capability. Specifically, double-sided sintered and single-sided emitter sintered yield better results, achieving approximately 7% extension of short-circuit withstand time (SCWT) at an optimal sintered layer thickness of 90 μm. The results can provide theoretical guidance for optimizing packaging design and enhancing short-circuit withstand capability in high-voltage, high-power press-pack IGBT devices.