Patent ID: 8551875

Claim:
A pattern forming method comprising: forming a first core film above a processing target; forming an opening pattern in a predetermined area of the first core film; conformally forming a mask film above the processing target above which the opening pattern is formed; performing etch-back of the mask film until an upper surface of the first core film is exposed so that the mask film remains on a side surface of the first core film; forming line-and-space shaped first core patterns that are made of the first core film and in which widths of line patterns have smaller than a width of the mask film remaining on the side surface of the first core film in an area other than an area forming the opening pattern; conformally forming a first sidewall film above the processing target above which the mask film and the first core patterns are formed; performing etch-back of the first sidewall film so that upper surfaces of the first core patterns are exposed; forming first sidewall patterns which are made of the first sidewall film above the processing target by removing the first core patterns; and patterning the processing target by using the mask film and the first sidewall patterns.