Understanding Inherent Implication of Thermal Resistance in Double-Side Cooling Module

The double-side cooling (DSC) packaging becomes more and more popular with the great demands of high power and fast speed, especially for silicon carbide metal oxide semiconductor field effect transistors. Measurements and modeling of thermal resistance are critical for thermal management of DSC module. However, the thermal resistance of DSC module is still unclear due to the asymmetric dual thermal paths. In this article, a clear understanding of thermal resistance of DSC module measured by transient dual-interface method (TDIM) is explained. The thermal impedance of DSC module is analyzed through time- and frequency-domain response of the DSC thermal model. The cooling conditions in TDIM have no influence on the measured thermal resistance of DSC module. The measured thermal resistance from junction to top case (or bottom case) is half of the actual value. The important conclusions are verified by transient simulations and experiments. Based on the results, a new definition of thermal resistance of DSC module is proposed for exact evaluation of thermal resistance and reliability.