Simulation study on the electro-thermo-mechanical effects of nano-silver solder layer and voids on press-pack IGBT

Press-pack IGBTs are well suited for high-capacity power equipment such as flexible DC converter valves, offering high power density, double-sided cooling, and fail-short characteristics. Their current conduction depends solely on mechanical contact, without wire bonds or solder layers, which enhances reliability and power capability. However, with increasing electrical stress, nonuniform temperature distribution across the chip becomes a major concern. To address this, Nano silver sintered solder layers are introduced to improve heat dissipation and reduce losses. Using COMSOL Multiphysics, this study develops an electro-thermo-mechanical model of a spring-loaded press-pack IGBT incorporating a Nano silver solder layer. By varying solder-layer thickness and void geometry, the model evaluates their effects on junction temperature and mechanical stress, clarifying how both the solder layer and its internal voids influence device performance.