Thermal characterization of Insulated Metal Substrates with a power test chip

This work shows a comparative thermal analysis between five different substrates suitable for the development of power modules: three Insulated Metal Substrates (IMS) of different grades, a Direct Copper Bonded (DCB) Alumina ceramic substrate and a standard FR4 Printed Circuit Board (PCB). The experimental data of the study has been obtained using a thermal characterization method based on a thermal test vehicle implemented with two high-power thermal test chips. These test assemblies behave like functional power modules but they allow accurate acquisition of thermal data (static and dynamic) using standard electronic instrumentation. Both, self-heating and thermal coupling effects between chips can be quantified in order to determine simulation parameters, to develop thermal models or to select the optimum substrate technology for a given application. In this work, the intermediate thermal behavior of IMS (between PCBs and DCBs) has been evidenced and quantified by their specific thermal resistances between chips and substrate backside.