Transient thermal modeling and characterization of a hybrid component

This paper deals with transient thermal modelling and characterisation of packaged semiconductor devices. The investigated semiconductor device is a hybrid thermal test structure consisting of a small thermal test chip bonded to a ceramic substrate. The dynamic thermal behaviour of this structure has been studied numerically and experimentally. Temperature step responses were calculated by means of finite element analysis. The impact of the die, die attach, and substrate material on the thermal impedance is presented. A compact model comprising lumped thermal resistances and capacitances is synthesised from the numerical step response data. In addition, thermal impedance measurements were performed on a hybrid thermal test vehicle. This study shows that transient thermal impedance measurements provide much more physical information about the internal heat flow path than steady-state thermal resistance measurements.