US4166148A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photomask blanks and photomasks prepared therefrom
Assignee: Konica Minolta Inc
•
Filing: 1977-08-15
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Granted: 1979-08-28
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Expires: 1997-08-15
Abstract
Abstract The photomask blank comprises a transparent substrate, a chromium film directly formed on the substrate and having a thickness of less than 15 mμ, an intermediate layer formed on the chromium film and containing chromium oxide and a metal mask layer made of chromium and formed on the intermediate layer. The intermediate layer comprises a single chromium oxide film or a composite layer of a chromium oxide film and a pure chromium film or a mixture of chromium and chromium oxide. The photomask is prepared by etching the chromium film, the intermediate layer and the mask layer of the photomask blank described above.
Inventors
- 👤 Kunio Sakurai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:09
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/54; G03F1/58; Y; Y10; Y10T; Y10T428/00; Y10T428/26
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
105 words
In a photomask blank of the type comprising an optically transparent substrate, and a metal mask layer formed on the surface of said substrate, the improvement which comprises a film formed of chromium directly in contact with said substrate, said chromium film having a thickness less than 15 mμ, and an intermediate layer containing chromium oxide interposed between said chromium film and said metal mask layer, the sum of the thicknesses of the chromium film and the intermediate layer being less than about 40 mμ, and a surface reflection preventing film made of chromium oxide and formed on the surface of said metal mask layer.
Claim 2
Dependent Claim
105 words
In a photomask blank of the type comprising an optically transparent substrate, and a metal mask layer formed on the surface of said substrate, the improvement which comprises a film formed of chromium directly in contact with said substrate, said chromium film having a thickness less than 15 mμ, and an intermediate layer containing chromium oxide interposed between said chromium film and said metal mask layer, the sum of the thicknesses of the chromium film and the intermediate layer being less than about 40 mμ, and a surface reflection preventing film made of chromium oxide and formed on the surface of said metal mask layer.
Claim 3
Dependent Claim
17 words
A photomask blank according to claim 1 wherein said intermediate layer comprises a single chromium oxide film.
Claim 4
Dependent Claim
24 words
A photomask blank according to claim 1 wherein said intermediate layer comprises a composite layer comprising a chromium oxide film and a chromium film.
Claim 5
Dependent Claim
19 words
A photomask blank according to claim 1 wherein said intermediate layer comprises a mixture of chromium oxide and chromium.
Claim 6
Dependent Claim
30 words
A photomask prepared by subjecting the metal mask layer, the chromium film and the intermediate layer of the photomask blank as set forth in claim 1 to an etching process.
References Cited (Backward Citations)
US3542612A
Cited
US3906133A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-08-27 | 1983-02-26 | 1983-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-08-27 | 1987-02-26 | 1987-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-08-27 | 1991-02-26 | 1991-08-28 | $7700.00 | Window Closed / Lapsed |