Study on Controlling Residual Stress in Thick Copper Film for Heat Sink Using Graphene

Nowadays, high-density electronic devices and component mounting have gained popularity. Because of the heat generated from these devices, efficiency of the electronic parts is significantly lowered and life time of these devices is considerably shortened. Therefore, it is very important to efficiently dissipate the heat generated from the device to extend product. In this study, a copper thick film was deposited using a sputtering technique using plasma. In addition, graphene, a two-dimensional nanomaterial, was inserted in the form of a sandwich structure between the deposited copper (Cu) layers of various thicknesses. Through this, a study was conducted to control the residual stress of thick copper foil deposited by sputtering. In this study, the residual stress was measured according to the location where graphene was inserted, the treatment method, and the transfer area. As a result, the highest residual stress reduction effect was observed when the transfer area of graphene was about 70%. Reduction of residual stress was observed by inserting graphene into the deposited copper thick film of various thicknesses. In addition, by increasing the number of layers of graphene inserted, changes in residual stress were observed.(Received 22 July, 2022; Accepted 23 September, 2022)