Patent ID: 7463347

Claim:
A simulator of an optical intensity distribution comprising: a field divider configured to divide an exposure field on a substrate into a first field and a second field, the first field being directly exposed to a light incident at the maximum incident angle, the maximum incident angle being determined by a numerical aperture of an optical projection system, the second field being prevented from being directly exposed to the light by a protrusion disposed on the substrate; a first optical intensity calculator configured to calculate an optical intensity of the first field by using a direct incident light component of the light; a second optical intensity calculator configured to calculate an optical intensity of the second field by using a reflected light component of the light reflected from a sidewall of the protrusion; a projected image simulation engine configured to simulate an optical intensity distribution of a projected image of a mask pattern on the substrate, based on the optical intensities of the first field and the second field; and a projected image memory module configured to store the optical intensity distribution of the projected image.