Theoretical analysis of thermal diffusion in power device packaging structures

Abstract The miniaturization and integration of power devices have led to a significant increase in power consumption and heat flux density. Research indicates that over 50% of power device failures are due to excessive temperature. Heat is transferred through the connection layer beneath the chip and ultimately dissipated by the heat sink. Power devices are composed of multiple stacked thin layers, with heat primarily transferring in the thickness direction. However, the heat flow path at the interface between materials of different sizes remains unclear. Based on heat transfer theory, this paper establishes a packaging and thermal conduction model for single-chip power devices. Through finite element analysis, the temperature distribution and thermal resistance distribution are obtained, providing methods for optimizing the packaging structure. The study finds that increasing the thickness of the base plate enhances heat diffusion and increases the effective heat transfer area, revealing the coexistence mechanism of heat conduction and heat diffusion. The accuracy of the model is verified through simulation and experiments, offering a basis for packaging design and material selection.