Patent ID: 7187084

Claim:
A damascene structure, comprising: a substrate; a lower intermetal dielectric layer over the substrate; an exposed conductive structure within the lower intermetal dielectric layer; a composite etch stop layer over the lower intermetal dielectric layer and the exposed conductive structure; the composite etch stop layer comprising a first lower sub-layer and a second upper sub-layer; the first lower sub-layer is an organic spin-on-polymer; and the second upper sub-layer is a silicon-containing dielectric layer; an upper intermetal dielectric layer over the composite etch stop layer; a trench interconnection opening forming within the upper intermetal dielectric layer and the composite etch stop layer: the trench interconnection opening, exposing the conductive structure; a barrier metal layer at least lining the trench interconnection opening; and a conductor plug within the trench interconnection opening, contacting the conductive structure, wherein an upper surface of the barrier metal layer is coplanar with an upper surface of the conductor plug.