Substrate thermal model reduction for efficient transient electrothermal simulation

Abstract

A multiport RC network reduction technique based on congruence transformation was developed specifically for improving the efficiency of temperature calculation in electrothermal simulations. This technique helps reduce the size of the three-dimensional lumped RC network, which is commonly used to model substrate heat conduction, while still preserving the input/output characteristics at the port nodes. A smaller thermal network leads to more efficient substrate temperature calculation. Furthermore, the reduced network can be combined with the device netlist to perform tightly-coupled electrothermal simulation for some cases when the large data size dictates the employment of the more time-consuming relaxation-based temperature calculation method. Our method is applicable to both static and dynamic electrothermal simulations for either localized or large-scale analyses. Runtime improvements in the range of 2/spl times//spl sim/3/spl times/ have been achieved in simulations.