Photomask blank and photomask
Abstract
Abstract A photomask is fabricated by forming, in a photomask (hard mask) produced by forming a patternized film of a masking material comprising (a) a layer of metallic chromium and (b) a layer of chromium oxides superposed thereon, a film of a translucent and electroconductive material selected from Nb, Ta and V, between the masking film and the transparent substrate. At the time of pattern transferring by photolithography, dropping off of parts of the pattern of this photomask does not occur even when it includes isolated island-like parts, and, at the time of inspection by electron-beam exposure, the precision of inspection does not lower. This photomask is obtained by patternizing by selective etching the masking film of a photomask blank produced by successively forming, on the transparent substrate, the translucent and electroconductive film and the masking film.
Inventors
- 👤 Satoru Kaneki
- 👤 Kazuhiro Tabuchi
Bibliographic Details
Claims Analysis
Total Claims: 8References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1988-12-02 | 1989-06-03 | 1989-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-02 | 1993-06-03 | 1993-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-02 | 1997-06-03 | 1997-12-03 | $7700.00 | Window Closed / Lapsed |