US4466859A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for etching copper
Assignee: PSI Star Inc
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Filing: 1983-12-06
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Granted: 1984-08-21
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Expires: 2003-12-06
Abstract
Abstract Process and structure for etching copper, as in the manufacture of printed circuit boards. The copper is exposed to a gaseous or liquid oxidant in the presence of a catalyst which promotes the reaction of copper with the oxidant. In some embodiments, the catalyst is carried by a medium which also serves as a receiver for oxidized copper species produced by the reaction, and in one preferred embodiment, the medium comprises a laminated structure having a first layer which contains a catalyst and a second layer which receives the oxidized copper species. The etching is substantially anisotropic, which alleviates the problem of undercutting.
Inventors
- 👤 Norvell J. Nelson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 06:43
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/02; C; C23; C23F; C23F1/00; C23F1/10; C23F1/12; C23F1/14
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
72 words
In a process for etching copper on a substrate, the steps or protecting the copper where it is to be preserved with a film of organic resist material, covering the surface of the copper and the resist material with a hydrogel mixture of water and a polymer containing a surfactant, exposing the surface to an oxidizing gas to dissolve the copper, and removing the mixture and the dissolved copper from the substrate.
Claim 2
Dependent Claim
72 words
In a process for etching copper on a substrate, the steps or protecting the copper where it is to be preserved with a film of organic resist material, covering the surface of the copper and the resist material with a hydrogel mixture of water and a polymer containing a surfactant, exposing the surface to an oxidizing gas to dissolve the copper, and removing the mixture and the dissolved copper from the substrate.
Claim 3
Dependent Claim
19 words
The process of claim 1 wherein the polymer is selected from the group consisting of polyacrylamide and poly(acrylic acid).
Claim 4
Dependent Claim
13 words
The process of claim 1 wherein the oxiding gas is NO 2 .
Claim 5
Dependent Claim
27 words
The process of claim 1 wherein the resist is a lead-tin solder and a small amount of phosphate is added to the mixture to preserve the resist.
Claim 6
Dependent Claim
24 words
The process of claim 4 wherein the phosphate is phosphoric acid and a smaller amount of an organic phosphate is added to the mixture.
References Cited (Backward Citations)
US2428464A
Cited
US2908557A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-08-21 | 1988-02-20 | 1988-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-21 | 1992-02-20 | 1992-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-21 | 1996-02-20 | 1996-08-21 | $7700.00 | Window Closed / Lapsed |