Multilayered metal capping barrier including CuSiN, for sub-65-nm technology nodes

A highly reliable interface of an ultrathin CuSiN self-aligned barrier between Cu film and nanoporous SiC:H film has been developed in the present work for the 65 nm node and below. It is shown that the multilayer of CuSiN (4 nm)/SiC:H (15 nm)/SiCN:H (10-15 nm) as a capping barrier have the enough ability to prevent copper diffusion at elevated temperatures even up to 500 degrees C, good barrier hermeticity, and appropriate mechanical characteristics. With this kind of barrier stack, higher interfacial adhesion between the Cu film and dielectric barrier is achieved. The mechanisms involved have been analyzed based on detailed characterization studies.