Patent ID: 8759177

Claim:
A pattern forming method, comprising: forming a pattern in which a first pattern in which a plurality of first line patterns extending in a first direction are arranged in a second direction orthogonal to the first direction and a second pattern arranged so as to be spaced apart from an end in the second direction of the first pattern with a space at a predetermined interval therebetween are mixed above a processing object; forming an inversion pattern having a periodic pattern in which the first line patterns of the first pattern and spaces therebetween are inverted and a non-periodic pattern arranged at an interval which is substantially equal to a width of the first line patterns from an end in the second direction of the periodic pattern so as to correspond to the spaces between the first line patterns in the first pattern and the space between the first pattern and the second pattern respectively above the processing object; conformally forming a sidewall film above the processing object above which the inversion pattern is formed; etching back the sidewall film so as to expose a top surface of the inversion pattern; selectively removing the periodic pattern of the inversion pattern whose top surface is exposed to form a sidewall pattern formed of the sidewall film above the processing object; and etching the processing object using the sidewall pattern and the non-periodic pattern surrounded by the sidewall film as masks.