Loss of adhesion strength of PVD Cu films on carbon substrates after heat treatment and correlated effects on the thermal interface properties

The study of coating-substrate systems consisting of a thin copper film on a flat carbon substrate is of great interest in order to get information on the interfacial behaviour of such systems. This work is focused on the mechanical adhesion strength and the correlated interfacial thermal contact resistance which are influenced by heat treatment. Using plasma-assisted pre-treatment of the carbon substrate prior to the deposition of copper coatings via physical vapor deposition (PVD), the adhesion strength between copper coatings and substrate has increased significantly, while the thermal contact resistance decreased in the as deposited state. After heat treatment at 800 °C for 1 h, considerably decreased adhesion strengths have been observed, accompanied by increased values of the thermal contact resistance.