A New Approach to Boundary Condition Independent Compact Dynamic Thermal Models

The paper introduces a new method for the generation of boundary condition independent dynamic thermal compact models. The procedure starts with a description of the component (e.g. semiconductor package, printed circuit board, etc.) and associated thermal ports at the continuous field level with a finite element code. Using order reduction methods a low order state space model is generated which represents the thermal behavior of the component. Additional matrix manipulations are applied to transform the state space model into a Kirchhoffian network that provides the transfer functions between all thermal ports. The method is demonstrated on an example from the semiconductor industry with a device package placed on a printed circuit board. By means of model coupling thermal simulation of the system is performed using the new boundary condition independent compact model. The results are finally compared to appropriate finite element simulations.