Electroless deposited CoWB for copper diffusion barrier metal

A metal capping barrier deposited by an electroless CoWB (cobalt tungsten boron) alloy plating method on damascene copper interconnects has been investigated. The metal capping barrier structure is one solution to prevent the decrease of coupling capacity associated with SiN or SiC capping barriers. In this paper, we propose a direct electroless deposition of Co alloy on copper surfaces, using dimethyl amine borane (DMAB) as a reducing agent, without a palladium catalyst.