US4378270A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of etching circuit boards and recovering copper from the spent etch solutions
Assignee: Shipley Co Inc
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Filing: 1981-10-29
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Granted: 1983-03-29
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Expires: 2001-10-29
Abstract
Abstract The present invention relates to a method of etching copper with a hydrogen peroxide-sulfuric acid etchant containing an acid soluble phosphonic acid in the manufacture of electronic circuits utilizing a masked copper surface and to a method of recovering the copper from the spent etch solution by electrolysis in solid continuous form saleable as electrolytic copper.
Inventors
- 👤 William R. Brasch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:45
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/46; C23F1/10; C23F1/14; C23F1/16; C23F1/18; C25; C25C; C25C1/00; C25C1/12
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
54 words
The method of recovering copper from spent hydrogen peroxide-sulfuric acid etching solutions which comprises adding an acid soluble organo phosphonic acid or salt to the etching solution prior to or after use of the solution as an etchant and electrodepositing the copper from the solution in the form of solid continuous pure copper metal.
Claim 2
Independent Claim
54 words
The method of recovering copper from spent hydrogen peroxide-sulfuric acid etching solutions which comprises adding an acid soluble organo phosphonic acid or salt to the etching solution prior to or after use of the solution as an etchant and electrodepositing the copper from the solution in the form of solid continuous pure copper metal.
Claim 3
Dependent Claim
25 words
The method according to claim 1 in which the organo phosphoric acid or salt is added prior to use of the solution as an etchant.
Claim 4
Dependent Claim
32 words
The method of claim 1 or 2 in which the phosphonic acid or salt is amino trimethyl phosphonic acid or a salt thereof or hydroxy ethylidene diphosphonic acid or a salt thereof.
Claim 5
Independent Claim
54 words
The method of etching copper which comprises treating the copper with an etch solution containing hydrogen peroxide, sulfuric acid and an acid soluble organo phosphonic acid or salt thereof and recovering the copper contained in the etch solution as a result of the copper etching by electrolytic deposition as solid continuous pure copper metal.
Claim 6
Independent Claim
54 words
The method of etching copper which comprises treating the copper with an etch solution containing hydrogen peroxide, sulfuric acid and an acid soluble organo phosphonic acid or salt thereof and recovering the copper contained in the etch solution as a result of the copper etching by electrolytic deposition as solid continuous pure copper metal.
Claim 7
Dependent Claim
53 words
A copper etching solution for copper circuit boards having the circuitry defined by a tin or tin-lead resist which comprises hydrogen peroxide, sulfuric acid, an acid soluble organo phosphonic acid or salt, phosphoric acid in an amount sufficient to retard etching of the solder resist, and a phenol stabilizer for the hydrogen peroxide.
Claim 8
Dependent Claim
53 words
A copper etching solution for copper circuit boards having the circuitry defined by a tin or tin-lead resist which comprises hydrogen peroxide, sulfuric acid, an acid soluble organo phosphonic acid or salt, phosphoric acid in an amount sufficient to retard etching of the solder resist, and a phenol stabilizer for the hydrogen peroxide.
Claim 9
Dependent Claim
17 words
The etching solution of claim 5 in which the stabilizer for the hydrogen peroxide is phenolsulfonic acid.
Claim 10
Independent Claim
47 words
The method of etching copper circuit boards to form a circuit which comprises etching the copper with a solution comprising hydrogen peroxide, sulfuric acid, an acid soluble phosphonic acid or salt, phosphoric acid and a phenol stabilizing agent for the hydrogen peroxide in the presence of copper.
Claim 11
Independent Claim
47 words
The method of etching copper circuit boards to form a circuit which comprises etching the copper with a solution comprising hydrogen peroxide, sulfuric acid, an acid soluble phosphonic acid or salt, phosphoric acid and a phenol stabilizing agent for the hydrogen peroxide in the presence of copper.
Claim 12
Dependent Claim
12 words
The method of claim 7 in which the stabilizer is phenolsulfonic acid.
Claim 13
Independent Claim
34 words
The method of claims 4, 5, 7 or 8 in which the phosphonic acid or salt is amino trimethyl phosphonic acid or a salt thereof or hydroxy ethylidene diphosphonic acid or a salt thereof.
Claim 14
Independent Claim
65 words
The method of etching copper circuit boards containing a resist pattern which comprises etching the copper with a hydrogen peroxide-sulfuric acid etching solution containing an acid soluble organo phosphonic acid or salt thereof in a sufficient amount to retard the etching rate of the hydrogen peroxide-sulfuric acid etching solution and to reduce the tendency of the etching solution to undercut the resist and produce overhang.
Claim 15
Independent Claim
65 words
The method of etching copper circuit boards containing a resist pattern which comprises etching the copper with a hydrogen peroxide-sulfuric acid etching solution containing an acid soluble organo phosphonic acid or salt thereof in a sufficient amount to retard the etching rate of the hydrogen peroxide-sulfuric acid etching solution and to reduce the tendency of the etching solution to undercut the resist and produce overhang.
Claim 16
Dependent Claim
21 words
An etch solution comprising hydrogen peroxide, sulfuric acid, an acid soluble organo phosphonic acid or salt, phosphoric acid and phenolsulfonic acid.
Claim 17
Dependent Claim
21 words
An etch solution comprising hydrogen peroxide, sulfuric acid, an acid soluble organo phosphonic acid or salt, phosphoric acid and phenolsulfonic acid.
References Cited (Backward Citations)
US4144119A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-03-28 | 1986-09-27 | 1987-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-28 | 1990-09-27 | 1991-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-28 | 1994-09-27 | 1995-03-29 | $7700.00 | Window Closed / Lapsed |