Patent ID: 7862988

Claim:
A method for forming a pattern, the method comprising: forming first mask patterns on a substrate; forming second mask patterns on sidewalls of the first mask patterns; forming third mask patterns at least partially filling spaces between adjacent second mask patterns; removing the second mask patterns, after forming the third mask patterns; and removing a portion of the substrate using the first and third mask patterns as etch masks, wherein each of the first mask patterns and the third mask patterns is formed of an organic layer containing silicon, and each of the second mask patterns is formed of an organic layer without silicon and is removed using oxygen plasma ashing to form a mask layer including the first mask patterns and the third mask patterns, wherein the first mask patterns are arranged in a striped shape having a pitch, the second mask patterns are arranged on the sidewalls and an upper surface of the first mask patterns, forming the third mask patterns includes, forming a photoresist containing silicon on the first and second mask patterns to fill the spaces between the adjacent second mask patterns, and removing an upper portion of the photoresist until the second mask patterns on the first mask patterns are exposed, and the second mask patterns cover an entirety of the sidewalls of the first mask patterns and an entirety of the upper surface of the first mask patterns such that the first mask patterns are protected by the second mask patterns during the removing of the upper portion of the photoresist.