Role of metal/matrix interfaces in the thermal management of metal-carbon composites

The increase in both power and packing densities in power electronic devices has led to an increase in the market demand for effective heat-dissipating materials, with high thermal conductivity and thermal expansion coefficient compatible with chip materials still ensuring the reliability of the power modules. In this context, metal matrix composites: carbon fibers, carbon nano fibers and diamond reinforced copper matrix composites among them are considered very promising as a next generation of thermal management materials in power electronic packages. These composites exhibit enhanced thermal properties compared to pure copper combined with lower density. This article presents the fabrication techniques of copper/carbon composite films by powder metallurgy and tape casting and hot-pressing; these films promise to be efficient heat-dissipation layers for power electronic modules. The thermal analyses clearly indicate that interfacial treatments are required in these composites to achieve high thermo-mechanical properties. Interfaces (through novel chemical and processing methods), when selected carefully and processed properly will form the right chemical/mechanical link between copper and carbon enhancing all the desired thermal properties while minimizing the deleterious effect. In this paper, we outline a variety of methods that are system specific that achieve these goals.