Patent ID: 8462317
Filing Date: 2013-06-11
Classification: G03F

Abstract:
1. An illumination optical system which illuminates an irradiated plane with illumination light provided from a light source and which is adapted for use in combination with a projection optical system for projecting a pattern arranged on the irradiated plane onto a photosensitive substrate, the illumination optical system comprising: a spatial light modulator which is arranged in an optical path of the illumination optical system and forms a desired light intensity distribution at a pupil position of the illumination optical system or a position optically conjugated with the pupil position; and a diffuser system which is arranged at an incidence side of the spatial light modulator through which the illumination light enters and diffuses the illumination light entering the spatial light modulator, the diffuser system including a first diffuser with a first diffusion characteristic that is replaceable with a second diffuser with a second, different diffusion characteristic, and making diffused light from one of the first diffuser and the second diffuser enter the spatial light modulator, wherein: the spatial light modulator includes a plurality of two-dimensionally arranged elements which receive the illumination light diffused by the diffuser system; and the plurality of elements are controllable independently from one another.