Recessed interconnet line having a low-oxygen cap for facilitating a robust planarization process and protecting the interconnect line from downstream etch operations

Abstract

Embodiments of the invention are directed to a method that includes forming a dielectric region having a dielectric region top surface, wherein the dielectric top surface is substantially planar. A first interconnect structure having a substantially planar interconnect structure top surface with unintended non-planar regions is formed in the dielectric region. A reinforced planarization process is applied that includes recessing the first interconnect structure top surface to a level that is below the dielectric region top surface and the unintended non-planar region, thereby removing the unintended non-planar region and forming a second interconnect structure having a second interconnect structure top surface that is substantially planar; forming a protective cap on the second interconnect structure top surface, wherein the protective cap has a sustantially planer protective cap top surface; and recessing the dielectric region top surface to a level that is substantially planar with the protective cap top surface.