Patent ID: 6939797

Claim:
A method for forming an interconnect structure on a substrate, the method comprising the steps of: depositing a dielectric layer, said dielectric layer being formed of a carbon-containing dielectric material having a dielectric constant of less than about 4; depositing a hardmask layer on said dielectric layer, said hardmask layer having a top surface; forming an opening in said dielectric layer and said hardmask layer; filling said opening with a conductive material, thereby forming a conductor, said conductor having a surface coplanar with the top surface of said hardmask layer; exposing said conductor to a reducing plasma comprising at least one gas selected from the group consisting of H 2 , N 2 , NH 3 and noble gases, thereby forming a pre-clean layer, said pre-clean layer comprising copper, silicon and oxygen; and depositing silicon nitride by a plasma-enhanced chemical vapor deposition (PE CVD) process, thereby forming a silicon nitride cap layer.