Patent US3820994A successfully refreshed from Google Patents.
US3820994A
Expired / Lapsed
US
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Penetration of polyimide films
Assignee: Westinghouse Electric Corp
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Filing: 1972-06-07
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Granted: 1974-06-28
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Expires: 1992-06-07
Abstract
Abstract There is disclosed a method of producing holes in polyimide films, typically KAPTON polyimide films, of substantial thickness, typically about .005 inches. Such films are typically used for multilayer solid-state circuits. An aluminum coating is deposited by vapor deposition on both surfaces of the film, typically to a thickness of about .0004 inches. A photoresist is deposited on the coating on each surface of the film and is imaged to define the holes in such manner that the areas of each hole in both sides of the film are coextensive. The film is developed exposing the aluminum over the areas of the holes. The aluminum at the hole areas is then etched or dissolved by an acid solvent. Thereafter the polyimide where the aluminum has been etched away and the unexposed photoresist are etched with hydrazine. Finally, the aluminum which is now exposed is removed by an acid solvent.
Inventors
- 👤 S Konsowski
- 👤 M Shamash
- 👤 F Lindberg
- 👤 S Ponemone
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:20
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/68; H10P14/683; G; G03; G03F; G03F7/00; G03F7/0015; H05; H05K; H05K3/00; H05K3/0011; H05K3/0017; H05K3/002; H10P50/00; H10P50/20; H10P50/28; H10P50/286; H10P50/287; H05K1/00; H05K1/02; H05K1/03; H05K1/0313; H05K1/032; H05K1/0346; H05K2201/00; H05K2201/01; H05K2201/0137; H05K2201/0154; H05K2203/00; H05K2203/05; H05K2203/0548; H05K2203/0554; Y; Y10; Y10S; Y10S438/00; Y10S438/942; Y10S438/948; Y10S438/95
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
27 words
The method of claim 1 wherein the dielectric material is a polyimide and the metal is at least one of the class consisting of aluminum and copper.
Claim 2
Dependent Claim
27 words
The method of claim 2 wherein the first coating is deposited by vaporizing a coating material of the coating metal and projecting the vapor on the film.
Claim 3
Dependent Claim
18 words
The method of claim 1 wherein the film is composed of a polyimide material and is relatively thick.
Claim 4
Dependent Claim
11 words
The method of claim 2 wherein the film is relatively thick.
Claim 5
Dependent Claim
53 words
The method of claim 2 wherein the metal is deposited by projecting vapor onto the film and wherein the deposition is initially at a high rate to achieve firm adhesion of the deposited metal and the film and thereafter is at a low rate to achieve a coating which may be readily etched.
Claim 6
Dependent Claim
22 words
The method of claim 6 wherein the deposit of the metal is reduced gradually from a high rate to a low rate.
Claim 7
Dependent Claim
32 words
The method of claim 1 wherein the dielectric material is composed of a polyimide and prior to the deposit of the metal film is outgassed by being heated in a low-pressure medium.
Claim 8
Dependent Claim
14 words
The method of claim 8 wherein after the outgassing the film is thoroughly cleaned.
Claim 9
Dependent Claim
34 words
The method of claim 1 wherein the dielectric material is a polyimide, wherein the second solvent is hydrazine solution and the film is subjected to the hydrazine solution at temperatures between 90* and 95*C.
Claim 10
Dependent Claim
19 words
The method of claim 10 wherein the solution is an aqueous solution of about 65 percent hydrazine in water.
Claim 11
Dependent Claim
23 words
The meThod of claim 1 wherein the metal is aluminum and the first solvent is a mixture of phosphoric, acetic and nitric acids.
Claim 12
Dependent Claim
21 words
The method of claim 12 wherein the coated film is subjected to the first solvent at a temperature of about 60*C.
Claim 13
Dependent Claim
36 words
The method of claim 12 wherein the composition of first solvent is of approximately the following composition in parts by volume: a. 375 of phosphoric acid b. 75 of acetic acid c. 15 of nitric acid
Claim 14
Dependent Claim
21 words
The method of claim 12 wherein the dielectric material is a polyimide and the second solvent is a solution of hydrazine.
Claim 15
Dependent Claim
17 words
The method of claim 1 wherein both surfaces of the film are coated with the first coating.
Claim 16
Dependent Claim
29 words
The method of claim 1 wherein the dielectric material is a polyimide which may be etched by hydrazine and the metal of the coating is substantially insoluble in hydrazine.
Claim 17
Dependent Claim
21 words
The method of claim 1 wherein both the penetration is etched and the masking photoresist is removed by the second solvent.
Claim 18
Independent Claim
168 words
The method of producing a predetermined selectably definable penetration in a film of polyimide which comprises coating said film at least on one face with a first coating of a metal of the class consisting of aluminum and copper, depositing a second coating of a photoresist material on said first coating, exposing said second coating to radiation so as to produce a pattern on said second coating defining the area of said penetration, processing said exposed second coating so as to expose the first coating or said area while the processed photoresist masks the remainder of said film, etching away the said exposed first coating on said area with a solvent, which does not appreciably dissolve said masking processed photoresist, to expose the polyimide in said area, said masking processed photoresist masking the first coating under it from dissolution, etching said area with hydrazine to produce said penetration while said first coating masks the remainder of said film, and thereafter removing said masking photoresist from said first coating.
Claim 19
Dependent Claim
13 words
The method of claim 19 wherein the hydrazine also removes the masking photoresist.
Claim 20
Dependent Claim
15 words
The method of claim 20 wherein the etching takes place at about 90* to 95*C.
Claim 21
Dependent Claim
21 words
The method of claim 1 wherein the masking photoresist is removed by a solvent which does not appreciably dissolve the metal.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |