Method of preventing copper poisoning in the fabrication of metal interconnects

Abstract

An improved method for fabricating metal interconnects on a semiconductor substrate comprises sequential formation of a copper layer, a first stop layer, a first inter-metal dielectric layer, a second stop layer, and a second inter-metal dielectric layer over the substrate. The second inter-metal dielectric layer and the second stop layer are defined to form an opening. A conformal first glue/barrier layer is formed over the substrate. The first glue/barrier layer and the first inter-metal dielectric layer are defined to form a via hole above the opening until the first stop layer is exposed. Spacers are formed on sidewalls of the opening and the via hole above the opening. The first stop layer at bottom of the via hole is removed to expose the copper layer.

Dependencies are inferred from the claim text.