Method for forming pattern

A method for forming patterns comprising:

• forming, on a substrate, a film to be processed;
• forming a first mask, which is a hard mask, on said film to be processed, by lithography, using a first photomask, wherein forming said first mask includes
• forming a first material film that becomes the material film of said first mask on said film to be processed,
• forming a first resist pattern by transferring the pattern of said first photomask onto said first material film, using lithography, said first photomask having a real pattern, which is an actual pattern on said film to be processed, and a dummy pattern added to control pattern pitch in said first photomask to within a prescribed range for resolution enhancement of the real pattern of the first photomask, and
• etching said first material film using said first resist pattern as an etching mask;
• forming a second mask, which is a hard mask, on said film to be processed and on said first mask, by lithography, using a second photomask, wherein forming said second mask includes
• forming a second material film that becomes the material film of said second mask on said film to be processed and on said first mask,
• forming a second resist pattern by transferring the pattern of said second photomask onto said second material film, using lithography, said second photomask having a pattern isolating a region in which said dummy pattern is formed from a region in which said real pattern is formed, and
• etching said second material film using said second resist pattern as an etching mask;
• and
• etching said film to be processed using said first mask and said second mask as etching masks.