Control of Cu Film Stress Deposited by Magnetron Sputtering Using Graphene Flake Layers

Abstract

Residual stress of a 10 μm thick copper (Cu) film deposited using direct current (DC) magnetron sputtering system was analyzed. Graphene flake, having high toughness and strength properties, was inserted in Cu film for decreasing residual stress. Compared with the Graphene sheet transfer method, a Cu film sample with Graphene flake inserted using a simple brush deposition method could be fabricated. By using a graphene flake layer, the Cu residual stress was decreased from 25.4 MPa to 14.6 MPa. As decreasing the Graphene flake area ratios from 100% to 40%, the residual stress was reduced to 2.8 MPa. A 50×50 mm size heat sink was fabricated to confirm the thermal diffusion of Graphene flake, and the LED device was mounted on it. As a result, graphene flake was obtained the result that improved thermal diffusion of the heat sink.