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