Patent ID: 8080877
Filing Date: 2011-12-20
Classification: H01L

Abstract:
1. A dual damascene structure, comprising: a substrate comprising thereon a base dielectric layer; a lower wiring layer inlaid in the base dielectric layer; a cap layer capping the lower wiring layer and the base dielectric layer; a dielectric layer on the cap layer; a via opening in the dielectric layer and the cap layer, wherein the via opening misaligns with the lower wiring layer thus exposing a portion of the lower wiring layer and a portion of the base dielectric layer, wherein the via opening comprises a bottom including a recessed area, and wherein a step height between the recessed area and a top surface of the lower wiring layer is less than 150 angstroms; a barrier layer lining interior surface of the via opening and covers the exposed lower wiring layer and the base dielectric layer, wherein only the barrier layer fills the recessed area; and a copper layer filling the via opening on the barrier layer.