Optical member of synthetic quartz glass for excimer lasers and method for producing same

摘要

PCT No. PCT/JP92/00821 Sec. 371 Date Mar. 15, 1993 Sec. 102(e) Date Mar. 15, 1993 PCT Filed Jun. 29, 1992 PCT Pub. No. WO93/00307 PCT Pub. Date Jan. 7, 1993.A synthetic quartz glass optical member for an ultraviolet laser, suitably applicable as a stepper lens of a lithographer using an excimer laser beam and other optical members, wherein the quartz glass has a hydroxyl content of 10 to 100 ppm, a chlorine content of 200 ppm or less, a hydrogen content of 1x1016 molecules/cm3 or less, a homogeneity of refractive index of 5x10-6 or less in terms of DELTA n, and a birefringence of 5 nm/cm or less. The optical member can be produced by subjecting a volatile silicon compound to flame hydrolysis with oxyhydrogen flame, depositing the formed particulate silica on a heat-resistant support to prepare a porous silica matrix, heating the matrix in a vacuum as high as 1x10-2 Torr or above to a temperature of 1,400 DEG C. or above to effect dehydration and degassing, homogenizing the resultant transparent quartz glass into highly homogeneous quartz glass free from striae in at last one direction, molding the highly homogeneous quartz glass, and annealing the molded glass.