Fabrication of copper-containing region such as electrical interconnect

Abstract

A copper-containing layer suitable for an electrical interconnect in a device such as an integrated circuit is created by a procedure in which a trench () is formed through a dielectric layer () down to a substrate (). A diffusion barrier () is provided over the dielectric layer and into the trench. Copper () is deposited over the diffusion barrier and into the trench. Chemical mechanical polishing is utilized to remove the copper outside the trench down substantially to the diffusion-barrier material overlying the dielectric layer. A sputter etch, typically of the reactive type, is then performed to substantially remove the diffusion-barrier material overlying the dielectric layer. The sputter etch typically removes copper above and/or in the trench at approximately the same rate as the diffusion-barrier material so as to substantially avoid the undesirable dishing phenomenon.