US4254174A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Supported membrane composite structure and its method of manufacture
Assignee: Massachusetts Institute of Technology
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Filing: 1979-03-29
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Granted: 1981-03-03
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Expires: 1999-03-29
Abstract
Abstract A process for fabricating polyimide membrane x-ray lithography masks is described. Thin membrane of polyimide is formed by spinning polyamic acid on a glass substrate and polymerizing in situ. The glass substrate acts as a holder and efficient heat sink during formation of gold absorber patterns on top of the polyimide. A support ring is then bonded to the polyimide, and the glass etched in dilute HF. Optically smooth polyimide membranes with thickness from 0.5 to 5 μm are readily achieved. The method and resulting product is not limited to the above materials or to masks.
Inventors
- 👤 Dale C. Flanders
- 👤 Henry I. Smith
- 👤 Muriel A. Dalomba
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:25
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/22; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24917; Y10T428/29; Y10T428/2913; Y10T428/2933; Y10T428/294
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
76 words
A supported membrane x-ray mask structure comprising: a mechanical support ring, an optically smooth film of polyimide plastic of less than six micrometer thicknesses bonded to said support ring to peripherally support said film only along the ring, said film being unsupported within the interior of said ring, and an x-ray absorber material bonded to said plastic film and being patterned to form an absorption pattern located within the interior unsupported region of said plastic film.
Claim 2
Dependent Claim
76 words
A supported membrane x-ray mask structure comprising: a mechanical support ring, an optically smooth film of polyimide plastic of less than six micrometer thicknesses bonded to said support ring to peripherally support said film only along the ring, said film being unsupported within the interior of said ring, and an x-ray absorber material bonded to said plastic film and being patterned to form an absorption pattern located within the interior unsupported region of said plastic film.
Claim 3
Dependent Claim
15 words
The structure of claim 1 wherein: said bonded x-ray absorber material is a metallic film.
References Cited (Backward Citations)
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US3179635A
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US3743842A
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US3742230A
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US3892973A
Cited
US4057659A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-02 | 1984-09-01 | 1985-03-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-02 | 1988-09-01 | 1989-03-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-02 | 1992-09-01 | 1993-03-03 | $7700.00 | Window Closed / Lapsed |