Illumination optics apparatus, exposure method, exposure apparatus, and method of manufacturing electronic device

摘要

An illumination optical apparatus which constantly controls a plurality of polarization states with high accuracy. An illumination optical system, which illuminates a pattern surface of a mask with illumination light, includes a polarization optical system and a depolarizer. The polarization optical system includes a half wavelength plate and PBS, which varies a polarization state of the illumination light to form a linear polarization state having a predetermined polarization direction. The depolarizer is arranged toward the mask from the polarization optical system and varies the polarization state of the illumination light emitted from the polarization optical system.