Method of fabricating semiconductor device

Abstract

A method of fabricating a semiconductor device includes forming an insulating layer and a peripheral structure on first and second regions of the substrate, forming first and second mask layers on the insulating layer and the peripheral structure, patterning the first and second mask layers to form first and second mask structures on the first and second regions, etching the insulating layer using the first and second mask structures as an etching mask, to form insulating patterns, forming a sacrificial layer in spaces between two adjacent insulating patterns on the first region, removing the second mask pattern on the first region by a dry etching process, forming an anti-oxidation layer on a surface of the second mask layer on the second region after removing the second mask pattern on the first region, and removing the second mask layer with the anti-oxidation layer by a wet etching process.