Heat Spreading and Heat Removal Needs of a Novel Power Electronics Package with Integrated Cooling

Abstract

Power electronics modules increasingly require compact and high-performance thermal packaging solutions capable of handling the resulting higher power densities. Double-sided cooled packages have been a promising solution to significantly reduce overall thermal resistance of packages below 0.2 K.cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /W. However, components with only single function prevent further reduction in the overall volume of the package. In this paper, a novel integrated cooling strategy is introduced for further miniaturization of power electronics package, where copper leads or vapor chambers are utilized as multi-functional layers for both power delivery and heat spreading. Parametric thermo-mechanical modeling is carried out with heat conduction-based models to understand the heat spreading and heat removal behavior of the integrated cooling solution. Despite the reduced number of package layers in the integrated cooling solution, thermomechanical performance enhancement is demonstrated over the standard package when vapor chambers are used to spread heat more effectively. Relative variation of one-dimensional and spreading thermal resistances of vapor chambers shows that an increase in the overall thickness of vapor chambers is only useful up to a certain cutoff thickness, beyond which thermal performance is reduced and package volume is increased excessively. If sufficiently high effective lateral thermal conductivity is achieved, use of ultra-thin vapor chambers is found to be even more advantageous to maximize power density of future power modules.