Silica glass and optical material
US7585800B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 2007 |
| Grant date | Sep 8, 2009 |
| Priority date | — |
| Expiry date | Dec 21, 2027 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03C2201/42
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
It is to obtain a silica glass suitable as a material for an optical material constituting an optical system to be used for EUVL, which has a low coefficient of thermal expansion from 0 to 100° C., and on which formation of concave defects is suppressed in a polishing step to achieve a high level of flatness.A silica glass containing from 0.1 to 10 mass % of Sn calculated as SnO2 and from 3 to 10 mass % of Ti calculated as TiO2, which has a homogeneity of the coefficient of thermal expansion from 0 to 100° C. to the temperature of from 50 to 200 ppb/° C., a coefficient of thermal expansion from 0 to 100° C. of 0±250 ppb/° C., and a Vickers hardness of at most 650.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.