Power Electronic Substrates for Space Restricted Application

High-power modules use substrates to house the semiconductor device and for electrical insulation. These substrates are constructed with thermally conductive dielectric material sandwiched between two metals to extract heat from semiconductor chips. Thus, the required cooling performance of a power module is linked to the substrate’s thermal performance and can vary based on the substrate technologies. In this study, four substrate technologies were evaluated for space-restricted applications: direct-bonded copper, an insulated metal substrate, a thermally annealed pyrolytic graphite–based insulated metal substrate, and direct-bonded aluminum, where the heat sink is directly attached without thermal interface materials. The finite element results suggest that the popular direct-bonded copper substrate has better thermal performance than the rest of the substrates for space-restricted applications. Furthermore, a modified direct-bonded copper is proposed to further improve thermal performance. The evaluation results show that the modified substrate can handle 30% more losses than its traditional counterpart.