High speed thermal coupling measurements for multichip electro-thermal model validation

A previously developed measurement method suitable for extracting transient thermal data for short term (100us-1s), high power, heating conditions was used to validate electro thermal models of multichip modules containing IGBTs in [1]. This work extends this technique for validation of thermal coupling behavior within multichip modules containing both IGBTs and MOSFETs for soft switching inverter topologies. By using the device threshold voltage as a time dependent temperature sensitive parameter (TSP), the thermal transient of a single device, along with the thermal coupling effect among nearby devices sharing common direct bond copper (DBC) substrates, can be studied under a variety of pulsed power conditions. Heating transients are made independently to a single device and the TSP of neighboring devices is monitored to determine if thermal coupling exists. The previously developed electro-thermal model in [9] has been modified to include chip to chip coupling effects and validated using the new double TSP method.