# US 8,539,797 B2 · Titania and sulfur co-doped quartz glass member and making method

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- Number: US 8,539,797 B2
- Document ID: US8539797B2
- Status: Granted
- Kind: B2
- Application number: 12/940,405
- Filed: 2010-11-05
- Published: 2011-05-19
- Granted: 2013-09-24
- Earliest claimed: 2009-11-16
- Assignees: Shin-Etsu Chemical Co., Ltd.
- Applicants: Shigeru Maida; Hisatoshi Otsuka
- Inventors: Shigeru Maida; Hisatoshi Otsuka
- Web page: https://patentgrep.com/patent/US8539797B2

## CPC

- G03F 1/22: Masks or mask blanks for imaging by radiation of 100nm or shorter wavelength, e.g. X-ray masks, extreme ultraviolet [EUV] masks; Preparation thereof
- C03B 19/1423: {Reactant deposition burners}
- C03C 3/06: with more than 90% silica by weight, e.g. quartz {(C03C3/045 takes precedence)}
- C03C 4/0085: {for UV-transmitting glass}
- C03B 2201/20: doped with non-metals other than boron or fluorine
- C03B 2201/42: doped with titanium
- C03C 2201/20: containing non-metals other than boron or halide
- C03C 2201/42: containing titanium
- Y02P 40/57: Improving the yield, e-g- reduction of reject rates
- 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)
- 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
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A titania and sulfur co-doped quartz glass member is provided. Due to co-doping of titania and sulfur, the quartz glass member undergoes zero expansion at a certain temperature and low thermal expansion over a wide temperature range, and is thus suited for use in a commercial EUV lithography tool. A manufacturing method and an optical member for EUV lithography are also provided.

## Claims

### Claim 1

A method for manufacturing a titania-doped quartz glass member, comprising the steps of subjecting a feed of a silicon source gas and a titanium source gas to flame hydrolysis with the aid of a combustible gas and a combustion-supporting gas, to form synthetic silica fine particles, depositing the silica fine particles on a rotating target, and concurrently melting and vitrifying the particles to form titania-doped quartz glass,
the feed further comprising a sulfur source gas whereby the resultant quartz glass is co-doped with titania and sulfur.

### Claim 2 (depends on 1)

The method of claim 1 wherein the sulfur source comprises a sulfur oxide or chloride.

### Claim 3 (depends on 1)

The method of claim 1 wherein flow rates of the combustible gas, the combustion-supporting gas, the feed of the silicon source gas, the feed of the titanium source gas, and the feed of the sulfur source gas are controlled within a variation of ±1%, and a temperatures of air flowing through a quartz glass-manufacturing furnace, exhaust gas from the furnace, and ambient air surrounding the furnace are controlled within a variation of ±2.5° C.

### Claim 4 (depends on 1)

The method of claim 1 wherein the rotating target is rotated at a rotational speed of at least 2 rpm.

### Claim 5 (depends on 1)

The method of claim 1 wherein the rotating target is rotated at a rotational speed of at least 5 rpm.

### Claim 6 (depends on 1)

The method of claim 1 wherein the rotating target is rotated at a rotational speed of at least 15 rpm.

### Claim 7 (depends on 3)

The method of claim 3 wherein the flow rates of the feed of the silicon source gas, the feed of the titanium source gas, the feed of the sulfur source gas, the combustible gas, and the combustion-supporting gas are each controlled within a variation of ±0.5%.

### Claim 8 (depends on 1)

The method of claim 1 wherein the titania and sulfur co-doped quartz glass member has a diameter of up to 1,000 mm.

### Claim 9 (depends on 1)

The method of claim 1 wherein the titania and sulfur co-doped quartz glass member is formed into a desired shape by hot working at a temperature of 1,500 to 1,800° C. for 1 to 10 hours such that the axis of the desired shape is parallel to a growth axis of the titania and sulfur co-doped quartz glass grown in the manufacture furnace.

### Claim 10 (depends on 9)

The method of claim 9 wherein after the hot working, the titania and sulfur co-doped quartz glass is annealed at a temperature of 700 to 1,300° C. in air for 1 to 200 hours, followed by cooling from the annealing temperature to 500° C. at a rate of 1 to 20° C./hr.

### Claim 11 (depends on 1)

The method of claim 1 wherein the titania and sulfur co-doped quartz glass contains 3 to 10% by weight of titania and 10 to 50,000 ppm of sulfur.