# US 5,703,712 A · Silica glass member for UV-lithography, method for silica glass production, and method for silica glass member production

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- Number: US 5,703,712 A
- Document ID: US5703712A
- Status: Granted
- Kind: A
- Application number: 08/509,223
- Filed: 1995-07-31
- Granted: 1997-12-30
- Earliest claimed: 1993-02-10
- Assignees: Nikon Corporation
- Inventors: Norio Komine; Hiroki Jinbo; Seishi Fujiwara; Hiroyuki Hiraiwa
- Web page: https://patentgrep.com/patent/US5703712A

## CPC

- C03B 19/1423: {Reactant deposition burners}
- C03B 19/1453: {Thermal after-treatment of the shaped article, e.g. dehydrating, consolidating, sintering}
- C03C 3/06: with more than 90% silica by weight, e.g. quartz {(C03C3/045 takes precedence)}
- C03C 4/0085: {for UV-transmitting glass}
- G02B 1/00: Optical elements characterised by the material of which they are made; Optical coatings for optical elements
- G02B 13/143: {for use with ultraviolet radiation}
- G03F 7/70241: {Optical aspects of refractive lens systems, i.e. comprising only refractive elements}
- G03F 7/70958: {Optical materials or coatings, e.g. with particular transmittance, reflectance or anti-reflection properties}
- C03B 2201/07: Impurity concentration specified
- C03B 2201/21: doped with molecular hydrogen
- C03B 2201/23: doped with hydroxyl groups
- C03B 2203/22: Radial profile of refractive index, composition or softening point
- C03B 2207/06: Concentric circular ports
- C03B 2207/12: Nozzle or orifice plates
- C03B 2207/20: Specific substances in specified ports, e.g. all gas flows specified
- C03B 2207/36: Fuel or oxidant details, e.g. flow rate, flow rate ratio, fuel additives
- C03C 2201/21: containing molecular hydrogen
- C03C 2203/44: chlorine containing
- C03C 2203/52: Heat-treatment
- Y10S 359/90: Methods
- Y10S 501/905: Ultraviolet transmitting or absorbing
- C03B: MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

Recent UV-lithography is required to provide a fine and sharp pattern with a line width of 0.5 .mu.m or less. The present invention provides a silica glass member adapted for use as an optical element for UV-lithography, by giving consideration to the RMS value of wave front aberration and the slant element of refractive index, which have not been considered in the art. Also, there is provided a silica glass member excellent in durability to the ultraviolet irradiation, by introduction of hydrogen molecules at the synthesis of the silica glass, instead of the using a secondary treatment for hydrogen introduction.

## Claims

### Claim 1

An optical element for use in UV-lithography in a specified wavelength region of 400 nm or shorter, comprising a silica glass member having a hydrogen molecule concentration which is equal to or higher than 5.times.10.sup.17 molecules/cm.sup.3 and which is higher in a central area than in a peripheral area.

### Claim 2 (depends on 1)

An optical element according to claim 1, wherein a diameter of said silica glass member is 150 mm or larger and a thickness thereof is 50 mm or larger.

### Claim 3 (depends on 1)

An optical element according to claim 1, wherein a difference in hydrogen molecule concentration between the central and peripheral areas does not exceed 2.times.10.sup.17 molecules/cm.sup.3.