US4747907A
Expired / Lapsed
US
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Metal etching process with etch rate enhancement
Assignee: International Business Machines Corp
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Filing: 1986-10-29
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Granted: 1988-05-31
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Expires: 2006-10-29
Abstract
Abstract A metal etching process involving an oxidation-reduction reaction where the metal being etched is oxidized and the active ingredient in the etchant solution is reduced, incorporates contacting said metal with an etching solution containing an active ingredient selected from the group consisting of ferric ions, ferricyanide ions, ceric ions, chromate ions, dichromate ions, and iodine, and introducing ozone into said etching solution to rejuvenate and agitate the solution.
Inventors
- 👤 John Acocella
- 👤 Lawrence D. David
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 04:18
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/32; C23F1/16
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
91 words
An etching process in which a metal is dissolved as cations from a surface of a body by contact with an etching solution comprising, contacting said metal, selected from the group consisting of Ni, Sn, Cu, Cr, and alloys of steel, stainless steel, with an etching solution, said etching solution having an active etching ingredient selected from the group consisting of ferric ions, ferricyanide ions, chromate ions, and dichromate ions, simultaneously introducing ozone into said etching solution to rejuvenate said solution, and to materially increase the etching rate of the metal.
Claim 2
Dependent Claim
91 words
An etching process in which a metal is dissolved as cations from a surface of a body by contact with an etching solution comprising, contacting said metal, selected from the group consisting of Ni, Sn, Cu, Cr, and alloys of steel, stainless steel, with an etching solution, said etching solution having an active etching ingredient selected from the group consisting of ferric ions, ferricyanide ions, chromate ions, and dichromate ions, simultaneously introducing ozone into said etching solution to rejuvenate said solution, and to materially increase the etching rate of the metal.
Claim 3
Dependent Claim
13 words
The etching process of claim 1 wherein said etching solution includes ferricyanide anions.
Claim 4
Dependent Claim
37 words
The etching process of claim 1 wherein said metal is Ni, and said etching solution has ferric ions as an active ingredient, and chloride anions, said solution having a pH in the range of -1 to +3.
Claim 5
Dependent Claim
19 words
The etching process of claim 1 wherein said ozone is formed by passing oxygen through a silent corona discharge.
Claim 6
Dependent Claim
15 words
The etching process of claim 4 wherein said ozone is bubbled through said etching solution.
Claim 7
Dependent Claim
28 words
The etching process of claim 1 wherein said body is comprised of a flexible backing element of an organic dielectric material that supports a layer of said metal.
Claim 8
Dependent Claim
43 words
The etching process of claim 6 wherein said body is prepared for selectively etching areas of said metal by depositing, exposing, and developing a resist layer on said metal that blankets selected areas of the metal and prevents contact of said etching solution.
Claim 9
Dependent Claim
36 words
The etching process of claim 1 wherein said ozone is introduced into said etching solution in a stream of oxygen and wherein the percent of ozone by weight is in the range of 0.1% to 10%.
Claim 10
Dependent Claim
54 words
The etching process of claim 1 wherein Mo is dissolved as anions from a surface of a body by contact with an etching solution, wherein said solution is a basic ferricyanide aqueous solution, simultaneously introducing ozone into said etching solution to rejuvenate said solution, and to significantly increase the etching rate of said solution.
Claim 11
Dependent Claim
21 words
The etching process of claim 4 wherein said etching solution is an aqueous solution and further includes potassium or sodium cations.
Claim 12
Dependent Claim
20 words
The etching process of claim 10 wherein said etching solution has a pH in the range of 9 to 14.
Claim 13
Dependent Claim
44 words
The etching process of claim 11 wherein said body is prepared for selectively etching areas of said metal by depositing, exposing, and developing a layer of resist on said metal that blankets selected areas of the metal and prevents contact of said etching solution.
Claim 14
Dependent Claim
19 words
The etching process of claim 12 wherein said ozone is formed by passing oxygen through a silent corona discharge.
Claim 15
Dependent Claim
93 words
An etching process in which a metal is dissolved as cations from a surface of a body by contact with an etching solution containing an active oxidizing agent comprising, contacting molybdenum with a solution containing an active agent consisting of a reduction-oxidation couple to be reversed with an electromotive force of less than 2.07 V in an acid solution, and an oxidation-reduction couple to be reversed with an electromotive force of less than 1.24 V in basic solution, introducing ozone into said etching solution to rejuvenate said solution and increase the etching rate.
Claim 16
Dependent Claim
93 words
An etching process in which a metal is dissolved as cations from a surface of a body by contact with an etching solution containing an active oxidizing agent comprising, contacting molybdenum with a solution containing an active agent consisting of a reduction-oxidation couple to be reversed with an electromotive force of less than 2.07 V in an acid solution, and an oxidation-reduction couple to be reversed with an electromotive force of less than 1.24 V in basic solution, introducing ozone into said etching solution to rejuvenate said solution and increase the etching rate.
Claim 17
Dependent Claim
13 words
The etching process of claim 14 wherein said etching solution contains ferricyanide ions.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1991-05-31 | 1991-11-30 | 1992-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-31 | 1995-11-30 | 1996-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-31 | 1999-11-30 | 2000-05-31 | $7700.00 | Window Closed / Lapsed |