US 7,585,598 B2
	Titania-doped quartz glass and making method, EUV lithographic member and photomask substrate
Shigeru Maida, Joetsu (Japan); and Motoyuki Yamada, Annaka (Japan)
Assigned to Shin-Etsu Chemical Co., Ltd., Tokyo (Japan)
Filed on Dec. 06, 2006, as Appl. No. 11/634,270.
Claims priority of application No. 2005-354488 (JP), filed on Dec. 08, 2005; and application No. 2006-318172 (JP), filed on Nov. 27, 2006.
Prior Publication US 2007/0134566 A1, Jun. 14, 2007
Int. Cl. G03F 1/00 (2006.01); C03C 3/06 (2006.01); G02B 1/00 (2006.01)

U.S. Cl. 430—5  [501/54]

13 Claims

1. A titania-doped quartz glass containing 3 to 12% by weight of titania at a titania concentration gradient less than or equal to 0.01 wt %/μm and having an apparent transmittance to 440 nm wavelength light of at least 30% at a thickness of 6.35 mm.