Method for forming fine patterns of a semiconductor device

Abstract

A method for forming fine patterns of a semiconductor device is disclosed and comprises the steps of: providing a semiconductor substrate; forming on the semiconductor substrate an objective layer to be etched; forming an intermediate layer over the objective layer; forming a first photoresist film over the intermediate layer; selectively exposing the first photoresist film through to a first exposure mask to light and create first photoresist patterns and thermally treating the first photoresist patterns; selectively etching the intermediate film to form intermediate patterns with the first photoresist patterns serving as a mask; forming a second photoresist film over the resulting structure; and selectively exposing the second photoresist film through a second exposure mask to light in such a manner that unexposed parts of the second photoresist film are partially overlapped with the first photoresist patterns, so as to form second photoresist patterns, whereby a significant improvement is brought into depth of focus, CD biasing and notching so that production yield and reliability are substantially enhanced