Taiwan Semiconductor Manufacturing Comp. Ltd.

Chi-Wen Li

Kei-Wei Chen

Jung-Chih Tsao

Steven Lin

Ray Chuang

Jye-Wei Hsu

Hsien-Pin Fong

A method of forming a copper interconnect in an opening within a pattern is described. The copper interconnect has an Rs that is nearly independent of opening width and pattern density. A first copper layer having a concave upper surface and thickness tis formed in a via or trench in a dielectric layer by depositing copper and performing a first CMP step. A second copper layer with a thickness twhere t&#x2266;tand having a convex lower surface is deposited on the first copper layer by a selective electroplating method. The first and second copper layers are annealed and then a second CMP step planarizes the second copper layer to become coplanar with the dielectric layer. The invention is also a copper interconnect comprised of the aforementioned copper layers where the first copper layer has a grain density (G)&#x2267;Gfor the second copper layer.

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Hsinchu, Taiwan

Chi-Wen Li