Patent ID: 7510980

Claim:
A method for manufacturing a semiconductor device, comprising: forming a first film, a second film and a third film in sequence on a silicon substrate, the first and third films being polycrystalline silicon and the second film including silicon oxide; forming a resist film on said third film; patterning said resist film by conducting an exposure and developing process for said resist film employing an exposure mask comprising a phase shifter; selectively dry-etching said third film through a mask of said resist film employing said second film as an etch stop to process said third film into a first pattern; further dry-etching said third film employing said second film as an etch stop to partially remove said third film, thereby processing said third film into a second pattern; patterning said second film through a mask of said third film having said second pattern; and patterning said first film employing said patterned second film as a mask.