Electromigration Improvement by Graphene on Cu Wire for Next Generation VLSI

The electro migration (EM) failure mode of copper (Cu) interconnects poses a major reliability concern. It has been found that using graphene as a capping layer on Cu could improve the EM failure. However, no reliability data have been reported for graphene grown on Cu damascene structures with foundry's back-end compatible process. In this study, we show that graphene can be selectively grown on Cu damascene structures as the capping layer on 12” wafers. An improvement in the EM lifetime was achieved through the graphene capping layer on the Cu line, and a nanotwin Cu structure with a graphene capping layer was also compared.