Methods of forming patterns for semiconductor devices

Abstract

Provided are methods of forming patterns of semiconductor devices, whereby patterns having various widths may be simultaneously formed, and a pattern density may be doubled by a double patterning process in a portion of the semiconductor device. A dual mask layer is formed on a substrate. A variable mask layer is formed on the dual mask layer. A first photoresist pattern having a first thickness and a first width in the first region, and a second photoresist pattern having a second thickness greater than the first thickness and a second width wider than the first width in the second region are formed on the variable mask layer. A first mask pattern and a first variable mask pattern are formed in the first region, and a second mask pattern and a second variable mask pattern are formed in the second region, by sequentially etching the variable mask layer and the dual mask layer by using, as etch masks, the first photoresist pattern and the second photoresist pattern. First spacers covering side walls of the first mask pattern and second spacers covering side walls of the second mask pattern are formed. The first mask pattern is removed, and then the substrate is etched in the first region and the second region by using the first spacers as an etch mask in the first region, and the second mask pattern and the second spacers as an etch mask in the second region.