Abstract The research of thermal contact resistance between multi-layers within press pack IGBTs (PP IGBTs) is significant for optimizing the PP IGBTs' thermal resistance to improve reliability, as the thermal contact resistance accounts for approximately 50% of the total thermal resistance of PP IGBTs. In this paper, thermal contact resistance between multi-layers is analysed via a finite element model (FEM) of a single fast recovery diode (FRD) submodule. Most importantly, the influence of temperature and clamping force on the thermal contact resistance is also discussed, and findings are verified by submodule thermal resistance experiments. Based on the FEM and experimental results, nanosilver sintering technology is proposed to fill the gap between the contact interfaces to reduce thermal contact resistance. The fabrication of a sintered single FRD submodule is also investigated in this paper, and the results of the sintered sample indicate that the thermal resistance is reduced by approximately 18.8% compared to a direct contact sample.