Methods for forming line patterns in semiconductor substrates

Abstract

A method for forming a fine pattern in a semiconductor substrate, comprises the steps of (a) coating a target layer to be etched on a semiconductor substrate with a resist composition comprising at least one compound capable of forming a photoresist pattern by a photolithography process, and a free radical initiator, wherein the free radical initiator is one which is capable of being decomposed by a thermal process at a temperature equal to or higher than the glass transition temperature of the at least one compound, wherein said coating step results in forming a resist compound layer comprising the resist composition; (b) performing a lithography process on the resist compound layer to form a photoresist pattern of at least one opening having a first width, wherein the target layer is exposed through the first width; and (c) heating the resist compound layer having the photoresist pattern formed therein to a temperature equal to or higher than the glass transition temperature of the at least one compound, and wherein a partial cross-linking reaction in the resist composition occurs by the free radicals produced from the free radical initiator resulting in a modified photoresist pattern having at least one opening having a second width which exposes the target layer, wherein the second width is smaller than the first width.