Fused silica glass and method for making the same
AssigneeCorning Incorporated
InventorsBrian Lee Harper, Kenneth Edward Hrdina, John Edward LaSala
Life of this patent
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Abstract
Disclosed are methods for hydrogen loading silica glass and silica glass comprising loaded H2. The methods can lead to H2 gradient in the glass material. Alternatively, the method may involve the use of varying H2 partial pressure of H2 in the atmosphere. Both can result in expedited hydrogen loading process.
Claims44
A silica glass material capable of being used in the light path of the lithographic irradiation of lithographic devices operating at a wavelength of below about 300 nm doped with molecular hydrogen having an average molecular hydrogen concentration [H2](avg) not lower than about 5×1015 molecules/cm3 and not higher than about 1×1018 molecules/cm3, a maximal molecular hydrogen concentration [H2](max) and a minimal molecular hydrogen concentration [H2](min), wherein 0.10≦[H2](min)/[H2](max)≦0.95, and less than 0.3 ppm variation in index of refraction, and wherein the silica glass material has a LIWFD measured at 633 nm of between −1.0 and 1.0 nm/cm when subjected to 10 billion pulses of a laser at approximately 193 nm, the laser operating at a fluence of approximately 70 μJ/cm2.
A method of producing silica glass material capable of being used in the light path of the lithographic irradiation of a lithographic device operating at a wavelength of below about 300 nm, comprising a step of treating the glass material in a hydrogen-containing atmosphere such that at the end of the treatment the silica glass material has an average molecular hydrogen concentration [H2](avg) not lower than about 5×1015 molecules/cm3 and not higher than about 1×1018 molecules/cm3, wherein a hydrogen concentration gradient exists through the depth of the material, said hydrogen concentration gradient having a maximum molecular hydrogen concentration [H2](max) and a minimum molecular hydrogen concentration [H2](min), wherein 0.10≦[H2](min)/[H2](max)≦0.95, leading to a variation in index of refraction of less than 0.3 ppm, and wherein the silica glass material has a LIWFD measured at 633 nm of between −1.0 and 1.0 nm/cm when subjected to 10 billion pulses of a laser at approximately 193 nm, the laser operating at a fluence of approximately 70 μJ/cm2.
A method of producing silica glass material having an average hydrogen concentration [H2](avg) not lower than about 5×1015 molecules/cm3 and not higher than about 1×1018 molecules/cm3, a maximal hydrogen concentration [H2](max) and a minimal hydrogen concentration [H2](min) wherein 0.10≦[H2](min)/[H2](max)≦0.95, less than 0.3 ppm variation in index of refraction, and a LIWFD measured at 633 nm of between −1.0 and 1.0 nm/cm when subjected to 10 billion pulses of a laser at approximately 193 nm, the laser operating at a fluence of approximately 70 μJ/cm2, the material being capable of being used in the light path of the lithographic irradiation of a lithographic device operating at a wavelength of below about 300 nm, comprising the following steps:
- (I) providing a silica soot preform comprising a plurality of silica soot particles;
- (II) treating the silica soot preform in an oxygen-containing atmosphere;
- (III) consolidating the silica soot preform to dense glass;
- and
- (IV) treating the consolidated silica glass in a hydrogen-containing atmosphere with varied hydrogen partial pressure, wherein a hydrogen partial pressure higher than the equilibrium hydrogen partial pressure corresponding to [H2](max) is employed at the during the initial stage of this step (IV) such that the —O—O— bonds and/or O2 molecules in the glass are quickly consumed.
Dependencies are inferred from the claim text.