Heat Dissipation Design of High-Power Wide-Bandgap Power Module with Insulated Metal Substrate

Abstract

In general, power modules are manufactured as direct bonding copper (DBC) substrates to withstand high temperatures and high power. The DBC substrate has a sandwich structure in which copper layers are formed on upper and lower parts and ceramic is formed as an insulating layer therebetween. Ceramic has excellent insulation properties but is difficult to process and is vulnerable to mechanical stress due to a difference in coefficient of thermal expansion (CTE) between copper. In this regard, research on the development of power modules using various materials is being conducted. In this paper, an insulating metal substrate (IMS) was designed and analyzed using a dielectric film as an insulating layer. IMS substrates are easier to process than ceramics and have a higher CTE, so they are more resistant to mechanical stress than DBC substrates. In addition, it may be made very thin through easy processing, thereby overcoming low thermal conductivity compared to ceramic. In this paper, IMS substrates of various thicknesses were designed based on the easy processability of the dielectric film, and simulations were performed to compare heat dissipation characteristics with Al2O3-based DBC substrates.