Patent ID: 7941767

Claim:
A photomask management method comprising: washing a photomask, measuring at least one physical amount of transmittance and phase difference of the photomask, dimension of a pattern, height of the pattern and a sidewall shape of the pattern after the washing, measuring a two-dimensional shape of a borderline pattern previously determined for the photomask after the washing, deriving lithography tolerance by performing a lithography simulation for the measured two-dimensional shape by use of the measured physical amount, and determining whether the photomask is usable based on the derived lithography tolerance, wherein the lithography simulation is performed by use of information containing a characteristic of an exposure device relating to a deviation from an ideal condition and an ideal exposure condition of a lithography process, and the lithography simulation is performed to derive one of a shape and dimension to which a transfer pattern of a borderline pattern on a wafer is set when an exposure condition varies due to the characteristic of the exposure device and other causes.