Interconnect formation in a semiconductor device

Abstract

A method for forming an interconnect of a semiconductor device includes: forming an interdielectric layer and a polishing stop layer on a semiconductor substrate; forming a depressed region on the substrate where the interconnect is to be formed; forming a conductive layer on the polishing stop layer so that the depressed region is filled with a conductive material; and removing upper portions of the conductive layer by chemical mechanical polishing so as to leave conductive material forming the interconnect in the depressed region. The chemical mechanical polishing selectivity ratio of the conductive layer to the polishing stop layer is 15:1 or more. In order to achieve such polishing selectivity ratio, the polishing stop layer is formed of a nitride layer or a tetraethylortho silicate layer, and the interconnect layer is formed of tungsten. The interdielectric layer is formed of an oxide layer.

Dependencies are inferred from the claim text.