Method for forming fine pattern in semiconductor device

Abstract

A method for forming fine pattern in a semiconductor device. It comprises the steps of: providing an objective material layer to be patterned covering a photosensitive film atop a semiconductor substrate; selectively exposing the surface of the photosensitive film, to determine a region to be patterned, in the surface of the photosensitive film; diffusing silicon into the surface of the photosensitive film by use of hexamethyl disilazane (HMDS) or tetramethyl disilazane (TMDS), to form a uniformly thin, silylated photosensitive material film at an unexposed surface of the photosensitive film and a thick, silylated photosensitive material film having a shape of convex lens at the exposed surface of the photosensitive film; etching the silylated photosensitive material layer and the photosensitive film with plasma containing NF.sub.3 /O.sub.2, in such a predetermined thickness as to remove the edge of the silylated photosensitive material having a shape of convex lens, to form a silylated photosensitive material pattern which finely determines the region to be patterned; and subjecting the photosensitive film exposed by the silylated photosensitive material pattern to anisotropic etch with oxygen-based plasma, to selectively expose the objective material layer to be patterned. Keeping the CD of the photosensitive film pattern constant, it can provide a clean and smooth surface.

Dependencies are inferred from the claim text.