ILLUMINATION OPTICAL SYSTEM, ALIGNER, AND PROCESS FOR FABRICATING DEVICE

摘要

Damage to optical members caused by excessive condensation of the light passed through a plurality of optical elements in a spatial light modulator is avoided.  An illumination optical system (IL), for illuminating a surface (M) to be illuminated based on the light from a light source (LS), comprises a spatial light modulator (4) having a plurality of optical elements arranged two-dimensionally and being driven individually, a detection section (DT) for detecting information about the drive state of the plurality of optical elements in the spatial light modulator, and a control section (CR) which determines, based on the information from the detection section, the possibility of excessive condensation of light on one point on a predetermined surface (6a) which is located at an optically Fourier transform position with respect to the surface where the plurality of optical elements are arranged on the rear side of the spatial light modulator, and thereby blocks or attenuates the propagation of the light toward the predetermined surface.