Evaluation of thermal resistance for metalized ceramic substrates using a microheater chip

Abstract Thermal dissipation performance is one of the key technologies in designing power modules because their output power and power density have been increasing year by year. Metalized ceramic substrates are generally used as an insulating material in high output power modules. Designing a proper module structure requires not only each material property but also understanding of the heat transfer in a module structure. An accurate measurement method of precise thermal properties for such metallized ceramic substrates is currently still missing. We had developed a new and simple measurement method for evaluating the heat releasing performance of metallized ceramic substrates in a mounted state. In this investigation, the thermal resistance of several kinds of Cu‐metalized ceramic substrates bearing an SiC microheater chip was evaluated. Si ₃ N ₄ with thermal conductivity, k , of 90 W/(m·K), AlN with k of 180 W/(m·K), and Al ₂ O ₃ with k of 30 W/(m·K) were employed. In all cases, the measured thermal resistance had an excellent accuracy within an error range of a few percent. In addition, it was revealed that the measured values had good agreement with the estimated values by finite element method (FEM) analyses.