A highly reliable interface of self-aligned barrier CuSiN thin layer between the Cu film and the nano-porous SiC：H （p-SiC：H） capping barrier （k=3.3） has been developed in the present work. With the introduction of self-aligned barrier （SAB） CuSiN between a Cu film and a p-SiC：H capping barrier, the interfacial thermal stability and the adhesion of the Cu/p-SiC：H film are considerably enhanced. A significant improvement of adhesion strength and thermal stability of Cu/p-SiC：H/SiOC：H film stack has been achieved by optimizing the pre-clean step before caplayer deposition and by forming the CuSiN-like phase. This cap layer on the surface of the Cu can provide a more cohesive interface and effectively suppress Cu atom migration as well.
