Imaging and nanoprobing of graphene layers for interconnects by conductive atomic force microscopy

Abstract

Graphene is a promising material to replace Cu-interconnect metallization under a width of 10 nm. We report a method for evaluating the graphene interconnect wiring structure by conductive atomic force microscopy (C-AFM), which enables the direct measurement of the two-dimensional (2D) resistance distribution and the coverage evaluation of multilayer graphene (MLG) grown on Ni interconnects using a 300 mm damascene process. The resistivity of exfoliated two-layer graphene was measured and a reasonable value of 30 µΩ·cm was obtained. We also measured the resistance of the MLG/Ni stack of 350 nm L/S patterns and confirmed the conduction paths of the MLG/Ni stack. It is demonstrated that the coverage of MLG on Ni interconnects can be estimated more precisely by C-AFM than by backscattered electron scanning electron microscopy (BSE-SEM) observation. C-AFM is demonstrated to be a potential technique for the local conductance evaluation of next-generation interconnects.