Patent ID: 7903530

Claim:
An optical system, comprising: a light source for generating a light beam of a designated wavelength; a target object on which the light beam generated from the light source is irradiated, the target object being a photomask having designated circuit patterns for the manufacture of a semiconductor device; a beam shaper in an optical path between the light source and the target object, the beam shaper splitting the light beam into a plurality of partial beams; and a polarization controller in the optical path between the light source and the target object, the polarization controller controlling the polarization states of the plurality of partial beams, wherein: the beam shaper includes a natural number n of partial areas, and each of the partial areas of the beam shaper includes a natural number m of subordinate areas, the subordinate areas having different thicknesses in accordance with their position in the beam shaper to split the light beam into the plurality of partial beams; and the polarization controller includes a plurality of bar patterns arranged in a designated direction, a pitch between the plurality of bar patterns is about 0.2 to 1.5 times the wavelength of the light beam, and a width of each bar pattern is about 0.2 to 0.8 times the pitch between the bar patterns.