Thermal impedance spectroscopy of power modules

In this paper, a method of thermal impedance spectroscopy for power modules is presented. This method enables a high resolution non-destructive analysis of the power module by means of electrical measurement and subsequent mathematical evaluation. The result provides a separation of partial thermal resistances corresponding material layers and facilitates a plausible estimation of geometrical dimensions of the power module package within the heat flow path. This method is applied for localization of failures during power cycling test.