Patent ID: 7501213

Claim:
A method for generating mask data for a photomask in which, on a transparent substrate having light transmitting properties with respect to exposure light, a mask pattern having light-shielding properties with respect to the exposure light and a light-transmitting portion of the transparent substrate where the mask pattern is not located are provided, characterized by comprising: a first step of determining the shape of a mask pattern based on a pattern to be formed using the photomask and setting the transmittance of the semi-light-shielding portion; a second step, after the first step, of extracting a region of the mask pattern having a predetermined dimension or less and interposed between parts of the light-transmitting portion; and a third step, after the second step, of inserting the phase shifter in each of the extracted region and part of the mask pattern located in the vicinity of the light-transmitting portion, wherein the mask pattern of the photomask includes: a semi-light-shielding portion which transmits the exposure light in the same phase as that of the light-transmitting portion; and a phase shifter which transmits the exposure light in a phase opposite to that of the light-transmitting portion, the semi-light-shielding portion has a transmittance which allows the exposure light to be partially transmitted, and the phase shifter is provided in a region of the mask pattern in which light transmitted through the phase shifter can cancel part of light transmitted through the light-transmitting portion and the semi-light-transmitting portion.