Transient Thermal Evaluation of SiC Chip Based Power Module Under Different Cooling Conditions

Abstract

In this paper, a SiC chip based power module with dual side cooling capability is proposed and the transient thermal characteristics of power module has been evaluated. The proposed power module eliminates the traditional direct bonded copper (DBC) substrate by replacing the DBC substrate with a dedicated copper lead frame (LF). As such the features of smaller form factor, lighter weight and lower cost have been achieved as compared with the conventional DBC substrate based power modules. To evaluate the transient thermal characteristics of the proposed SiC chip based high power module, the upcoming tasks have been conducted in this study. At first, the thermal model of the power module is constructed based on the proposed structure and recommended materials. Then the transient thermal simulation is carried out to simulate the thermal characteristics of the SiC chip based power module under different cooling conditions and power cycling profiles (on/off cycle). An appropriate cooling method and cycling profile is recommended for the power cycling test of the power module. Meanwhile, the test vehicles of the power module with the recommended materials are fabricated for the power cycling test and transient thermal evaluation. At last, the power cycling test has been carried out with a commercial power cycling test setup. The case and junction temperature of the power module at each power cycle have been measured. The simulation results match well with measurement results.