ALD growth of a mixed-phase novel barrier for seedless copper electroplating applications

A novel plasma enhanced atomic layer deposition (PEALD)-grown mixed-phase/nano-laminate barrier has been developed which combines the robust barrier properties of TaN with direct plate characteristics of Ru. It was observed that the mixed phase barrier as thin as 2-5 nm can be designed to act both as robust copper barrier and as a copper direct plating layer by modulating the Ru: Ta ratio in the deposited films. The filling characteristics in sub-50 nm features were found to be equivalent to those of conventionally copper-seeded interconnect structures.