Wonsik Kim¹, Sang-Min Kim², Byungil Hwang³, Seung Min Han¹; ¹Korea Advanced Institute of Science and Technology, ²Korea Institute of Machinery and Materials, ³Chung-Ang University

Cu-graphene multilayer composite, as an interconnect material, is a very promising material system. Metal-graphene nanolayered composite is known to have ultra-high strength as the graphene hinders dislocation movements across its interface. The same graphene can be an effective interface for deflecting fatigue cracks that are generated under cyclic bending. In this work, Cu-graphene composites were tested for bending fatigue, which have shown 5 times enhancement in fatigue resistance compared to conventional Cu thin film. Fatigue cracks that are generated within the Cu layer were observed by the cross-sectional SEM and TEM to be stopped by the graphene interface. In MD simulation, Cu-graphene showed limited accumulation of dislocations at the film/substrate interface. In addition, more efficient fabrication process of Cu-graphene composite, by dry transfer of graphene and electrodeposition of Cu, is proposed. Nano-pillar indentation are performed and compared with previous studies to confirm that this Cu-graphene composite display similar strengthening effect.