Improved electromigration-resistance of Cu interconnects by graphene-based capping layer

We demonstrated that reduced graphene oxide (rGO) can suppress electromigration (EM) of Cu interconnect lines. This improvement in the EM lifetime is attributed to the presence of functional groups between the rGO and Cu atoms. Further enhancement of the EM lifetime was achieved by increasing the functionality of graphene by mixing graphene oxide (GO) with polyvinylpyrrolidone (PVP). It is revealed that the dominant EM path of Cu is successfully changed from the surface to grain boundaries by the use of an ultrathin (2.5 nm) PVP/GO capping layer.