Patent ID: 8587128

Claim:
A damascene structure, comprising: a conductive layer; a first dielectric layer disposed on the conductive layer, the first dielectric layer having a via therein; a first barrier metal layer disposed on a via bottom and a via sidewall of the via in the first dielectric layer, the first barrier metal layer covering the conductive layer on the via bottom; a barrier layer covering the first barrier metal layer, wherein the barrier layer is comprised of a material different with that of the first barrier metal layer and comprises a first laterally extending portion and a second laterally longitudinally extending portion, the first laterally extending portion covers a portion of the first barrier metal layer disposed on the via bottom, the second laterally longitudinally extending portion covers the first barrier metal layer disposed on the via sidewall, and a thickness of the first laterally extending portion is thinner than a thickness of the second laterally longitudinally extending portion; and a second barrier metal layer covering the barrier layer on the via sidewall, exposing the barrier layer on the via bottom.