Influence of Surface Morphology of Press-Pack IGBT on Temperature and Thermal Resistance

Abstract:
The main work of this paper is to use the finite element method to establish a two-dimensional finite element model of press-pack IGBT power device, and calculate the temperature change of each material layer and the contact thermal resistance between each material layer through the thermo-electric coupling algorithm. Since the thermal contact resistance between the Al metallization layer and the emitter Mo plate increases more dramatically during the power cycle of the press-packed IGBT device, the two-dimensional surface morphology of the contact interface between the Al metallization layer and the emitter Mo plate is established by the W-M fractal function, and the influence of the two-dimensional surface morphology under different roughness on the junction tempera-ture of the press-packed IGBT chip and the thermal contact resistance between the Al metallization layer and the emitter Mo plate during the power cycle is analyzed. The results show that with the change of the contact interface roughness between the Al metallization layer and the emitter Mo plate in the press pack IGBT device, the contact thermal resistance between the chip junction temperature and the material layer during the power cycle is also changing. Therefore, the two-dimensional contact interface equivalent model with different roughness established in this paper can simulate the surface morphology of the contact interface with different power cycles.