Effects of Post-annealing and Co Interlayer Between SiNx and Cu on the Interfacial Adhesion Energy for Advanced Cu Interconnections

Abstract

Effects of Co interlayer and 200 degrees C post-annealing treatment on interfacial adhesion energy of SiNx/Cu structure were systematically investigated. Initial interfacial adhesion energy of SiNx/Cu structure measured by double cantilever beam test was 0.92 J/m(2). The interfacial adhesion energy increased to 2.94 J/m(2) with Co interlayer between SiNx and Cu films. After post-annealing treatment at 200 degrees C for 500 h, the interfacial adhesion energy of SiNx/Co/Cu structure decreased to 0.95 J/m(2). X-ray photoelectron spectroscopy analysis revealed that the interfacial adhesion energy increased for SiNx/Co/Cu thin films due to CoSi2 reaction layer at SiNx/Co interface, but sharply decreased during post-annealing treatment by SiO2 formation at SiNx/Co interface.