Copper-Graphene Foams: A New High-Performance Material System for Advanced Package-Integrated Cooling Technologies

Copper-graphene foams are explored as a new class of porous, high-performance materials for advanced thermal management in high power applications. Due to the continuous demand for enhanced performance and miniaturization in power electronics, such as for automotive drive inverters, this trend has led to high-power densification and package designs with increasing thermal densities - unavoidable increases in operating temperatures and consequent drops in device and system level reliability. Furthermore, the emergence of advanced high-frequency wide-bandgap devices and their fast adoption in power electronics is further aggravating this trend, with larger amounts of heat generated in smaller localized areas. Thermal management has become a critical challenge, such that it is often the limiting factor in system performance and reliability. Towards addressing this bottleneck, a number of advanced package-integrated cooling solutions including vapor chambers for heat spreading and micro-cooling chips for near-junction heat removal have been proposed and demonstrated. To further miniaturize these thermal structures and extend their application to higher thermal densities in packages, more performance improvements are necessary, achieved through innovations in materials such as the use of open-cell conductive foams. Copper foams with different cell sizes and compression levels were evaluated and characterized for the impact of different microstructures. They were coated with graphene by chemical vapor deposition, showing significant improvements in thermal properties. Copper-graphene foams can provide a possible route for material-driven innovation and development in packaging with improved properties addressing industry needs.