Patent ID: 7883834

Claim:
A method for forming patterns comprising: forming a film on a substrate; forming a first hard mask over said film, by lithography, using a first photomask, wherein forming said first hard mask includes forming said first hard mask over said film, forming a first resist pattern by transferring the pattern of said first photomask over said first hard mask using photolithography, said first photomask having a real pattern, which is an actual pattern over said film, and a dummy pattern added to control pattern pitch in said first photomask, and etching said first hard mask using said first resist pattern as an etching mask; forming a second hard mask over said film and on said first hard mask, by lithography, using a second photomask, wherein forming said second hard mask includes forming said second hard mask over said film and on said first hard mask, forming a second resist pattern by transferring the pattern of said second photomask over said second hard mask, using photolithography, 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 hard mask using said second resist pattern as an etching mask; and etching said film using said first hard mask and said second hard mask as masks.