Electroless deposition of Co-based barriers: selectivity, corrosion and growth properties.

Abstract

International audienceElcctroless metallic caps are convincing alternatives to standard SiC(N) barriers for the 45 nm technology node and beyond to improve electromigration resistance and limit the dielectric constant of the structures. In this work, particular emphasis is put on possible selectivity issues, corrosion of the copper lines and nucleation/growth properties for two processes (Pd-activated Co\VP and Pd-free CoWB) deprniited in an industrial 300 mm equipment Co\VP process exhibits promising results for 12 nm nominal thickness. For both processes, the control of the preclean step seems to be fundamental to limit copper corrosion. Under optimal conditions, line resistance increase is limited to less than 3 %