Enhanced Interfacial Bonding in Copper/Diamond Composites via Deposition of Nano-copper on Diamond Particles

Abstract

The currently available heat-sink materials cannot meet the requirements for the 5G and beyond technology. Copper (Cu)/diamond composites have been proposed because Cu and diamond are excellent thermal conductors, while diamond has a very low coefficient of thermal expansion. Mixing Cu and diamond to form a composite seems a straightforward approach. However, this simple approach has never succeeded because, chemically, Cu does not wet diamond. Therefore the Cu-diamond interface cannot be tightly bonded, leading to an inferior thermal conductivity. This study presents a modified press and sinter process for depositing Cu submicronic particles onto diamond reinforcements prior to densification by hot pressing. The initial results obtained from microstructural observations and x-ray photoelectron spectroscopy have shown that our strategy can lead to successful Cu deposition onto diamond particles. The Cu deposition leads to a well-bonded interface between the copper matrix and diamond reinforcement, ultimately resulting in excellent thermal conductivity.