Method of fabricating semiconductor device having self-aligned contact plug

Abstract

Methods of fabricating a semiconductor device having a self-aligned contact plug are provided. Methods include forming a lower insulating layer on a semiconductor substrate, forming a plurality of interconnection patterns parallel to each other on the lower insulating layer; forming an upper insulating layer that is configured to fill between the interconnection patterns, and forming a plurality of first mask patterns crossing the plurality of interconnection patterns, ones of the plurality of first mask patterns parallel to each other on the semiconductor substrate having the upper insulating layer. Methods may include forming a second mask pattern that is self-aligned to the plurality of first mask patterns and that is between ones of the plurality of first mask patterns, etching the upper insulating layer and the lower insulating layer using the first and second mask patterns and the plurality of interconnection patterns as etch masks to form a plurality of contact holes exposing the semiconductor substrate, and forming a plurality of contact plugs in respective ones of the plurality of contact holes. Semiconductor devices are also provided.