TITANIUM OXYNITRIDE HARD MASK FOR LITHOGRAPHIC PATTERNING

摘要

A vertical stack including a dielectric hard mask layer and a titanium nitride layer is formed over an interconnect-level dielectric material layer such as an organosilicate glass layer. The titanium nitride layer may be partially or fully converted into a titanium oxynitride layer, which is subsequently patterned with a first pattern. Alternately, the titanium nitride layer, with or without a titanium oxynitride layer thereupon, may be patterned with a line pattern, and physically exposed surface portions of the titanium nitride layer may be converted into titanium oxynitride. Titanium oxynitride provides etch resistance during transfer of a combined first and second pattern, but can be readily removed by a wet etch without causing surface damages to copper surfaces. A chamfer may be formed in the interconnect-level dielectric material layer by an anisotropic etch that employs any remnant portion of titanium nitride as an etch mask.

主权项

1. A method of forming a patterned structure comprising:
forming a vertical stack including an interconnect-level dielectric material layer, a dielectric hard mask layer, and a patterned titanium oxynitride layer defining a first pattern over a substrate, wherein said patterned titanium oxynitride layer is formed by:
forming a blanket titanium nitride (TiN) layer on said dielectric hard mask layer;converting an upper portion of said blanket TiN layer into a blanket titanium oxynitride layer; andpatterning said blanket titanium oxynitride layer with said first pattern; forming a patterned lithographic material stack including at least a patterned photoresist layer over said titanium oxynitride layer, said patterned photoresist layer defining a second pattern; and etching said interconnect-level dielectric material layer employing a combination of said patterned lithographic material stack and said patterned titanium oxynitride layer to form a cavity embedded within said interconnect-level dielectric material layer.