Thermal stress failure analysis of power diode SMBF package

With the development of power devices, the thermal reliability of power devices has become a research hot spot. The research object of this paper is the power diode of SMBF package. Through X-ray scanning and resin removal observation, it can be concluded that the excessive thermal stress of SMBF package may be the cause of its failure. Using ANSYS Workbench software simulation, the results show that the reduction of thermal expansion coefficient of resin can reduce the thermal stress. When the coefficient of thermal expansion is reduced from 11*10-6C-1 to 9*10-6C-1, the maximum shape variable of the device is reduced by 80.72%. When the thermal conductivity of the resin is reduced from 4.75W/(m*C) to 5.58W/(m*C), the junction temperature is reduced by 7.76%.