The thermal resistance of power modules is critical to determine the safe operating area and by extension, application specifications. Typical methods of thermal characterization determine steady state thermal resistance values. However, the system transient thermal response is of equal importance due to the conceptual RC thermal network that comprises the module, determining dynamic thermal behavior. Traditionally, this thermal impedance has been extracted using complex methods and only describes thermal impedance as a lumped average. This paper proposes an infrared-based observation method that utilizes image topography to determine die-to-die thermal impedance. The model can be used to predict detailed die response under different system level loads. Intra-die thermal coupling is a feature of the modeling technique to detect hot-spots and abnormalities. Experimental results are presented to validate the claims of this work.
