Photomask blank, photomask blank making method, and photomask making method
US11073756B2 · kind B2 · utility
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3References
7Claims
0Family size
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Key dates
| Filing date | Jul 12, 2018 |
| Grant date | Jul 27, 2021 |
| Priority date | — |
| Expiry date | Oct 6, 2038 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/80
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A photomask blank is provided comprising a transparent substrate, a first film of chromium-containing material on the substrate, and a second film of silicon/oxygen-containing material disposed contiguous to the first film. The second film includes a first layer contiguous to the first film and a second layer spaced apart from the first layer in film thickness direction. The oxygen content of the first layer is lower than the oxygen content of the second layer. During etching of the first film, this setting prevents an etching rate from ramping up at the interface between the first and second films.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.