Optical member and method of producing the same, and projection aligner

摘要

An optical member of the invention is an optical member for photolithography used together with light having a wavelength of not more than 250 nm. The optical member is made of a fluoride crystal in which a maximum diameter dmax (cm) of scattering bodies existing internally and a quantity ns of the scattering bodies per 1 cm3 satisfy a condition represented by following formula (1): 0<dmax2xns<6.5x10-4 (cm-1) (1)