Method for forming fine patterns in semiconductor device

Abstract

Disclosed is a method of forming a fine pattern in a semiconductor device using a photolithography process, which comprises: coating a photoresist layer for an I-line and a positive type ArF photoresist layer on a semiconductor substrate that includes a conductive layer; performing exposure and a first baking process on the resultant substrate by using an etch-mask of a desired pattern to produce alcohol radicals (OH ) or carboxyl acid (COOH) in the positive type ArF photoresist layer, in which a silylation reaction can be produced; removing the etch-mask; performing a development process to the resultant structure to form a first photoresist pattern; performing exposure and a second baking process on the substrate that includes the first photoresist pattern; performing a silylation process to the substrate to which the second baking process has been performed, by using an HMDS to form a silicon oxide layer on the surface of the first photoresist pattern through reaction between the alcohol radicals (OH ) or the carboxyl acid (COOH) and the HMDS; performing a dry development process to the photoresist layer for the I-line by using the first photoresist pattern along with the silicon oxide layer as an etch-mask in order to form a second photoresist pattern; and etching the conductive layer by using the first and second photoresist patterns together with the silicon oxide layer as an etch-mask in order to form bit-lines.