TiO2-containing silica glass and optical member for EUV lithography using high energy densities as well as special temperature controlled process for its manufacture
US8178450B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 26, 2010 |
| Grant date | May 15, 2012 |
| Priority date | — |
| Expiry date | Aug 26, 2030 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P40/57
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The present invention provides a TiO2—SiO2 glass whose coefficient of linear thermal expansion in the range of the time of irradiation with EUV light is substantially zero when used as an optical member of an exposure tool for EUVL and which has extremely high surface smoothness. The present invention relates to a TiO2-containing silica glass having a TiO2 content of from 7.5 to 12% by mass, a temperature at which a coefficient of linear thermal expansion is 0 ppb/° C., falling within the range of from 40 to 110° C., and a standard deviation (σ) of a stress level of striae of 0.03 MPa or lower within an area of 30 mm×30 mm in at least one plane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.