QUARTZ GLASS AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To provide quartz glass which is used as a lens material for the image formation optical system of ultraviolet laser for excimer laser lithography or the like, and to provide a method for producing the same. SOLUTION: In quartz glass synthesized by the direct method using raw materials comprising organosilicon compounds, the quartz glass having an internal absorption coefficient of <=0.001 cm-1 in the wavelength region of >=190 nm is obtained by suppressing the concentration of formyl radicals formed in the inside of the quartz glass by X-ray irradiation to be not more than 2×1014 radical/cm3.