Method of forming a copper oxide film to etch a copper surface evenly

Abstract

A method of forming a copper oxide film on a copper surface, particularly applicable to forming copper wiring interconnects in the semiconductor industry, allows copper surfaces to be etched more evenly than in conventional methods. The step of forming a copper oxide film on a copper surface comprises exposing the copper surface to a mixed solution of aqueous ammonia and aqueous hydrogen peroxide, which has been adjusted to have a pH of 8 to 10. A copper oxide surface can also be exposed to a solution of aqueous ammonia and aqueous hydrogen peroxide, which has been adjusted to have a pH of 10 to 11. When such a copper oxide surface is etched using acid or alkali, the exposed copper surface is smoother than conventional etching, resulting in better copper interconnect structures that can include conductive diffusion barriers.

Dependencies are inferred from the claim text.