Invention Grant
US09586850B2 Method for producing titanium-doped silica glass for use in EUV lithography and blank produced in accordance therewith 有权
用于EUV光刻中使用的掺杂钛的石英玻璃的方法和根据其生产的空白

Method for producing titanium-doped silica glass for use in EUV lithography and blank produced in accordance therewith
Abstract:
The Ti3+ ions present in Ti-doped silica glass cause a brown staining of the glass, causing inspection of the lens to become more difficult. Known methods for reducing Ti3+ ions in favor of Ti4+ ions in Ti-doped silica glass include a sufficiently high proportion of OH-groups and carrying out an oxygen treatment prior to vitrification, which both have disadvantages. In order to provide a cost-efficient production method for Ti-doped silica glass, which at a hydroxyl group content of less than 120 ppm shows an internal transmittance (sample thickness 10 mm) of at least 70% in the wavelength range of 400 nm to 1000 nm, the TiO2—SiO2 soot body is subjected to a conditioning treatment with a nitrogen oxide prior to vitrification. The blank produced in this way from Ti-doped silica glass has the ratio Ti3+/Ti4+≦5×10−4.
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