Patent ID: 7799510

Claim:
A method for fabricating a semiconductor device, comprising the steps of: correcting design pattern data including data of a plurality of design patterns; performing electron beam writing on an electron beam resist formed on a mask blank on the basis of the corrected design pattern data; developing the electron beam resist to form an etching mask; etching the mask blank using the etching mask to form a photomask; transferring a mask pattern formed on the photomask to a photoresist formed on a base substrate by irradiating the photomask with exposure light; developing the photoresist to form an etching mask; and etching a base substrate using the etching mask; wherein correcting the design pattern data includes the steps of: extracting an isolated pattern having an optically isolated portion from the mask pattern; and providing, in an adjacent pattern extending parallel to the isolated portion of the isolated pattern and having a terminal end, an extended portion extending from the terminal end next to the isolated portion of the isolated pattern along a direction in which the isolated portion of the isolated pattern extends.