Photomask blank and making method
US11061319B2 · kind B2 · utility
1Cited by
1References
18Claims
0Family size
Assignee
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Key dates
| Filing date | Jun 4, 2018 |
| Grant date | Jul 13, 2021 |
| Priority date | — |
| Expiry date | Aug 29, 2038 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/84
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A photomask blank is processed into a transmissive photomask for use in photolithography for forming a pattern on a recipient using exposure light. The photomask blank comprises a transparent substrate, a first film of a material which is etchable by chlorine/oxygen-based dry etching, and a second film of a silicon-containing material. The second film includes a layer having a refractive index n of at least 1.6 or an extinction coefficient k of at least 0.3 with respect to the wavelength of inspection light which is longer than the exposure light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.