Patent ID: 7906435

Claim:
A method of manufacturing a semiconductor device comprising: depositing a first hard mask on a material to be processed; forming a first resist pattern of a roughly rectangular closed loop on said first hard mask; etching said first hard mask into a roughly rectangular closed loop using said first resist pattern as a mask; depositing a second hard mask on said material and said first hard mask after removing said first resist pattern; etching said second hard mask anisotropically into a roughly rectangular closed loop which encloses said first hard mask on both sides of said first hard mask; etching said material using said second mask with a roughly rectangular closed loop as a mask after selectively removing said first hard mask; forming a second resist pattern on said second hard mask before etching of said materials; and etching said second hard mask so that said roughly rectangular closed loop converts into two roughly symmetrically U shaped open loops whose openings face each other using said second resist pattern as a mask.