US4846929A
Expired / Lapsed
US
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Wet etching of thermally or chemically cured polyimide
Assignee: International Business Machines Corp
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Filing: 1988-07-13
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Granted: 1989-07-11
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Expires: 2008-07-13
Abstract
Abstract Polyimide is etched by contacting the polyimide with an aqueous solution of a metal hydroxide followed by contact with an acid followed by contact with an aqueous solution of a metal hydroxide. Etching of chemically cured polyimide can be enhanced by employing a presoaking in hot water. Also, partially etched chemically cured polyimide is removed with a concentrated acid solution. In preparing a metal coated polyimide structure for subsequent gold plating, two flash etching steps with the polyimide etch between are employed after developing the photoresist.
Inventors
- 👤 Steven L. Bard
- 👤 Claudius Feger
- 👤 John J. Glenning
- 👤 Gareth G. Hougham
- 👤 Steven E. Molis
- 👤 Walter P. Pawlowski
- 👤 John J. Ritsko
- 👤 Peter Slota, Jr.
- 👤 Randy W. Snyder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 04:37
CPC Classifications
C; C08; C08J; C08J7/00; C08J7/12; H; H05; H05K; H05K3/00; H05K3/0011; H05K3/0017; H05K3/002; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/286; H10P50/287; C08J2379/00; C08J2379/04; C08J2379/08; H05K1/00; H05K1/02; H05K1/03; H05K1/0313; H05K1/032; H05K1/0346; H05K2201/00; H05K2201/01; H05K2201/0137; H05K2201/0154; H05K2203/00; H05K2203/07; H05K2203/0779; H05K2203/0786; H05K2203/0793; H05K3/10; H05K3/108
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
43 words
A process for etching a fully cured or substantially fully cured polyimide layer which comprises contacting said polyimide layer with an aqueous solution of a metal hydroxide, followed by contact with an acid, followed by contact with an aqueous solution of metal hydroxide.
Claim 2
Dependent Claim
43 words
A process for etching a fully cured or substantially fully cured polyimide layer which comprises contacting said polyimide layer with an aqueous solution of a metal hydroxide, followed by contact with an acid, followed by contact with an aqueous solution of metal hydroxide.
Claim 3
Dependent Claim
13 words
The process of claim 1 wherein said hydroxide is an alkali metal hydroxide.
Claim 4
Dependent Claim
16 words
The process of claim 1 wherein said hydroxide is sodium hydroxide, potassium hydroxide, or mixtures thereof.
Claim 5
Dependent Claim
17 words
The method of claim 3 wherein the concentration of said hydroxide is at least about 4 molar.
Claim 6
Dependent Claim
18 words
The method of claim 3 wherein the concentration of said hydroxide is about 4 to about 15 molar.
Claim 7
Dependent Claim
17 words
The method of claim 1 wherein the concentration of said hydroxide is at least about 4 molar.
Claim 8
Dependent Claim
18 words
The method of claim 1 wherein the concentration of said hydroxide is about 4 to about 15 molar.
Claim 9
Dependent Claim
20 words
The method of claim 1 wherein the solution of metal hydroxide contains up to about 15% by volume of N-Methyl-2-Pyrrolidone.
Claim 10
Dependent Claim
18 words
The method of claim 8 wherein the amount of N-Methyl-2-Pyrrolidone is about 3% to about 15% by volume.
Claim 11
Dependent Claim
23 words
The method of claim 1 wherein the solutions of metal hydroxide are employed at temperatures of about 60° C. to about 100° C.
Claim 12
Dependent Claim
18 words
The method of claim 1 wherein said acid is hydrochloric acid, acetic acid, sulfuric acid, or mixtures thereof.
Claim 13
Dependent Claim
18 words
The method of claim 1 wherein at least about 1 molar aqueous solution of said acid is employed.
Claim 14
Dependent Claim
18 words
The method of claim 1 wherein at least about 3 molar aqueous solution of said acid is employed.
Claim 15
Dependent Claim
19 words
The method of claim 1 wherein about 3 to about 8 molar aqueous solution of said acid is employed.
Claim 16
Dependent Claim
36 words
The method of claim 1 wherein said polyimide is heat cured polyimide that was heated to temperatures of at least about 350° C., but not greater than about 485° C. for at least about 30 minutes.
Claim 17
Dependent Claim
17 words
The method of claim 1 wherein said hydroxide is potassium hydroxide and said acid is hydrochloric acid.
Claim 18
Dependent Claim
12 words
The method of claim 1 wherein said acid is an inorganic acid.
Claim 19
Dependent Claim
12 words
The method of claim 1 wherein said acid is an organic acid.
Claim 20
Dependent Claim
53 words
A process for etching a chemically cured polyimide layer which comprises contacting said polyimide layer with water at a temperature of about 55° C. to about 95° C. for a time sufficient to increase the etch rate of the polyimide and thereafter contacting said polyimide with an etchant to thereby etch said polyimide.
Claim 21
Dependent Claim
53 words
A process for etching a chemically cured polyimide layer which comprises contacting said polyimide layer with water at a temperature of about 55° C. to about 95° C. for a time sufficient to increase the etch rate of the polyimide and thereafter contacting said polyimide with an etchant to thereby etch said polyimide.
Claim 22
Dependent Claim
16 words
The process of claim 19 wherein said temperature is about 70° C. to about 95° C.,
Claim 23
Dependent Claim
14 words
The process of claim 19 wherein said time is at least about 30 seconds.
Claim 24
Dependent Claim
16 words
The process of claim 19 wherein said etchant is an aqueous solution of a metallic hydroxide.
Claim 25
Dependent Claim
13 words
The process of claim 22 wherein said hydroxide is an alkali metal hydroxide.
Claim 26
Dependent Claim
15 words
A process for removing partially etched chemically cured polyimide by contacting with an inorganic acid.
Claim 27
Dependent Claim
15 words
A process for removing partially etched chemically cured polyimide by contacting with an inorganic acid.
Claim 28
Dependent Claim
11 words
The process of claim 24 wherein said acid is sulfuric acid.
Claim 29
Dependent Claim
19 words
The process of claim 25 wherein the concentration of said acid is about 20% to about 70% by volume.
Claim 30
Dependent Claim
19 words
The process of claim 25 wherein the concentration of said acid is about 22% to about 25% by volume.
Claim 31
Dependent Claim
21 words
The process of claim 25 wherein the temperature of said acid is about 75° C. up to the boiling point thereof.
Claim 32
Dependent Claim
85 words
A process for etching metallized polyimide structures which comprise: providing a polyimide substrate having on both major surfaces a pattern of metal lines and relatively thin metal seed layer; providing a photoresist on said metal seed layer; exposing and developing said layer to define those areas where polyimide is to be subsequently etched; flash etching said seed metal from those areas where the polyimide is to be subsequently etched; stripping said photoresist; and flash etching the remaining seed metal that was protected by the photoresist.
Claim 33
Dependent Claim
85 words
A process for etching metallized polyimide structures which comprise: providing a polyimide substrate having on both major surfaces a pattern of metal lines and relatively thin metal seed layer; providing a photoresist on said metal seed layer; exposing and developing said layer to define those areas where polyimide is to be subsequently etched; flash etching said seed metal from those areas where the polyimide is to be subsequently etched; stripping said photoresist; and flash etching the remaining seed metal that was protected by the photoresist.
Claim 34
Dependent Claim
20 words
The process of claim 29 wherein said photoresist is a negative photoresist and is laminated onto said metal seed layer.
Claim 35
Dependent Claim
16 words
The process of claim 29 wherein said metal seed layer is copper on top of chromium.
Claim 36
Dependent Claim
20 words
The process of claim 29 wherein said polyimide is chemically cured polyimide and is etched with an alkali hydroxide solution.
Claim 37
Dependent Claim
52 words
The process of claim 32 wherein said polyimide is etched by contacting said polyimide with water at a temperature of about 55° C. to about 95° C. for a time sufficient to increase the etch rate of the polyimide and thereafter contacting said polyimide with an etchant to thereby etch said polyimide.
Claim 38
Dependent Claim
17 words
The process of claim 33 wherein partially etched polyimide is removed by contacting with an inorganic acid.
Claim 39
Dependent Claim
11 words
The process of claim 34 wherein said acid is sulfuric acid.
Claim 40
Dependent Claim
17 words
The process of claim 29 which further includes coating metal lines on the polyimide substrate with gold.
Claim 41
Dependent Claim
50 words
The process of claim 29 wherein said polyimide layer is thermally cured polyimide layer and is etched by contacting said polyimide layer with an aqueous solution of a metal hydroxide, followed by contact with an aqueous solution of an acid, followed by contact with an aqueous solution of metal hydroxide.
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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) | 1992-07-10 | 1993-01-09 | 1993-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-10 | 1997-01-09 | 1997-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-10 | 2001-01-09 | 2001-07-11 | $7700.00 | Window Closed / Lapsed |