Patent US4722878A successfully refreshed from Google Patents.
US4722878A
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US
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Photomask material
Assignee: Mitsubishi Electric Corp
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Filing: 1985-11-12
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Granted: 1988-02-02
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Expires: 2005-11-12
Abstract
Abstract A photomask material comprising a transparent glass substrate, a polysilicon layer formed on the transparent glass substrate, a transition metal film formed on the polysilicon layer, the metal film being capable of being etched by means of the same dry etching process as that used for the polysilicon layer, and a protective polysilicon layer formed on the transition metal film.
Inventors
- 👤 Yaichiro Watakabe
- 👤 Kazuhiro Tanaka
- 👤 Masahiro Hirosue
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:42
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/54; G03F1/38; G03F1/48; G03F1/50
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
64 words
A photomask material comprising: a transparent glass substrate; a first polysilicon layer formed on said transparent glass substrate; a metal film formed on said first polysilicon layer, said metal film being formed of a metal being etched by means of the same dry etching process as that used for the first polysilicon layer; and a second protective polysilicon layer formed on said metal film.
Claim 2
Dependent Claim
64 words
A photomask material comprising: a transparent glass substrate; a first polysilicon layer formed on said transparent glass substrate; a metal film formed on said first polysilicon layer, said metal film being formed of a metal being etched by means of the same dry etching process as that used for the first polysilicon layer; and a second protective polysilicon layer formed on said metal film.
Claim 3
Dependent Claim
17 words
A photomask material in accordance with claim 1, wherein said metal film comprises a transition metal film.
Claim 4
Dependent Claim
28 words
A photomask material in accordance with claim 2, wherein said transition metal film is selected from a group consisting of molybdenum, tungsten and titanium and a combination thereof.
Claim 5
Dependent Claim
17 words
A photomask material in accordance with claim 1, wherein said transparent glass substrate is a silica glass.
Claim 6
Dependent Claim
19 words
The photomask of claim 1, wherein said first and second polysilicon layers are each formed of the same material.
Claim 7
Dependent Claim
42 words
The photomask of claim 5, wherein said first polysilicon layer is approximately 50 to 100 Å in thickness, said metal layer being approximately 600 to 800 Å in thickness and said second polysilicon layer being approximately 100 to 200 Å in thickness.
Claim 8
Dependent Claim
21 words
The photomask of claim 6, wherein said dry etching process occurs at an etching rate of approximately 1000 Å per minute.
Claim 9
Dependent Claim
16 words
The photomask of claim 6, wherein said first and second polysilicon layers are formed by sputtering.
Claim 10
Dependent Claim
37 words
The photomask of claim 1, wherein said first and second polysilicon layers each cut off the passage of UV radiation therethrough while permitting passage of radiation in the visible region, said metal layer cutting off visible light.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-02-01 | 1991-08-03 | 1992-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-01 | 1995-08-03 | 1996-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-01 | 1999-08-03 | 2000-02-02 | $7700.00 | Window Closed / Lapsed |