Patent US3652273A successfully refreshed from Google Patents.
US3652273A
Expired / Lapsed
US
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Process using polyvinyl butral topcoat on photoresist layer
Assignee: International Business Machines Corp
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Filing: 1967-09-11
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Granted: 1972-03-28
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Expires: 1987-09-11
Abstract
Abstract An improved process for the formation of photo-resist patterns on substrates by coating the subtrate with a layer of a synthetic resin photo-resist composition, applying a topcoat of vinyl butyral polymer over the photo-resist, exposing the photo-resist to a light pattern through a mask and the transparent topcoat, and removing the photo-resist from the unexposed areas with a conventional predominantly aromatic hydrocarbon developer which also removes the topcoat. The use of the topcoat eliminates scumming of the substrate due to residual insoluble photo-resist in the unexposed areas of the resist layer, and reduces pinholing in the exposed areas.
Inventors
- 👤 Maung S Htoo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:08
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/02; H05K3/06; H05K3/061; H05K3/064; G; G03; G03F; G03F7/00; G03F7/004; G03F7/09; G03F7/092; H05K2203/00; H05K2203/05; H05K2203/0562; H05K2203/0577
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
23 words
The method of claim 1 wherein said polymer is a copolymer comprising vinyl alcohol, vinyl acetate and a major portion of polyvinyl butyral.
Claim 2
Dependent Claim
27 words
The method of claim 2 wherein said copolymer comprises 88 percent copolymerized vinyl butyral, 9-12 percent copolymerized vinyl alcohol and up to 2.5 percent copolymerized vinyl acetate.
Claim 3
Dependent Claim
13 words
The method of claim 2 wherein said synthetic resin photo-resist comprises polyvinyl cinnamate.
Claim 4
Dependent Claim
24 words
The method of claim 2 wherein the film is coated on the photo-resist layer as a solution of the copolymer in a lower alkanol.
Claim 5
Dependent Claim
11 words
The method of claim 5 wherein said lower alkanol is isopropanol.
Claim 6
Dependent Claim
13 words
The method of claim 1 wherein said synthetic resin photo-resist comprises polyvinyl cinnamate.
Claim 7
Dependent Claim
15 words
The method of claim 1 wherein said photo-resist comprises polyvinyl cinnamate and a light sensitizer.
Claim 8
Dependent Claim
25 words
The method of claim 1 wherein the film is coated on the photo-resist layer as a solution of the vinyl butyral in a lower alkanol.
References Cited (Backward Citations)
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BE659130A
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US3155509A
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US3518084A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-03-28 | 1975-09-27 | 1976-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-28 | 1979-09-27 | 1980-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-28 | 1983-09-27 | 1984-03-28 | $7700.00 | Window Closed / Lapsed |