silica glass optical materials for projection lens using to vacuum ultraviolet ray lithography and manufacturing method therefor and projection lens

摘要

It is an object of the present invention to provide a quartz glass optical material for a projection lens used in vacuum ultraviolet lithography, a method of manufacturing the same, and a projection lens, and as a solution thereof, used in vacuum ultraviolet lithography having a wavelength of 155 to 195 nm. In the quartz glass optical material for a projection lens, the ultra high purity is 1 to 10 wtppm of OH group, 100 to 10000 wtppm of F, and H ₂ to 1 × 10 ^{17 to} 1 × 10 ¹⁹ molecules / cm 3, and the F concentration distribution is It is characterized by being symmetrical about the central axis. With the above structure, the quartz glass optical material of the present invention has high initial transmittance to vacuum ultraviolet rays having a wavelength of 155 to 195 nm, and is excellent in high precision, high durability and homogeneity.