Method of manufacturing semiconductor device including sequentially forming first and second mask material layers and forming a dotted photoresist pattern on the second mask material layer

A method of manufacturing a semiconductor device, comprising:

• sequentially forming mask material layers A and B on a base layer;
• forming a dotted photoresist pattern in a square or triangular lattice layout on the mask material layer B;
• forming a first insulating film, which is intended to form sidewall spacers, on the photoresist pattern, with a recess left at least in the vicinity of a central portion of the square or triangular lattice layout of the dotted photoresist pattern;
• etching back the first insulating film by dry etching to expose the photoresist, removing the photoresist that is exposed and forming the sidewall spacers by further etching back, wherein the sidewall spacers have a photoresist-removed portion that exposes the mask material B and a first hole pattern corresponding to the recess;
• etching the mask material B using the sidewall spacers as a mask to form second holes corresponding to the first hole pattern in the mask material B;
• etching the mask material A using the mask material B as a mask to form third holes in the mask material A by, wherein the third holes have a diameter greater than that of the second holes of the mask material B;
• forming a second insulating layer on the mask material B to a thickness such that openings of the second holes are closed to form voids in the third holes of the mask material A;
• forming a mask pattern exposing the base film in fourth holes corresponding to the voids in the third holes by dry etching;
• and
• forming holes corresponding to the fourth holes by etching the base layer using the mask pattern as a mask.