US3775202A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Etching control system
Assignee: DEA PROD Inc
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Filing: 1972-03-13
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Granted: 1973-11-27
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Expires: 1992-03-13
Abstract
Abstract In an etching system utilizing ferric chloride solution or equivalent spray directed onto copper work pieces to be etched, the etchant in the etcher sump is circulated through a chlorinator under control of an etching control monitor. This introduces gaseous chlorine and effectively maintains the etching potential of the ferric (Fe 3) ions present in the solution. As copper accumulates in the etchant, a part is removed, ammonium chloride is added, and this mixture is then cooled. A crystallized double salt containing copper is separated, and the solution, thus reduced in copper content, is stored for subsequent reintroduction to the etching system.
Inventors
- 👤 J Meek
- 👤 E Vieane
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:33
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/46
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
58 words
Process according to claim 1 in which a sufficient amount of etching solution of lower copper content than that in the etching zone is added periodically to maintain the volumetric supply in the etching zone and to keep the copper content of liquid in said zone between about 6 and 9 ounces of copper per gallon of liquid.
Claim 2
Dependent Claim
39 words
Process according to claim 1 in which the withdrawn used etchant is regenerated for reuse by removing at least a substantial part of its copper content and regenerated etchant is used, in part at least, to replace that withdrawn.
Claim 3
Dependent Claim
31 words
Process according to claim 3 in which copper content in the liquid in the etching zone is maintained at a level between about 7 and 9 ounces per gallon of liquid.
Claim 4
Dependent Claim
35 words
Process according to claim 1 in which the chlorine addition rate is set at least high enough to balance stoichiometrically related maximum rate of copper addition to the etching bath due to the etching operation.
Claim 5
Dependent Claim
37 words
Process according to claim 1 wherein fresh etchant of substantially no copper content is introduced periodically and automatically to replace liquid lost from the bath and to maintain a predetermined volumetric liquid level in said etching zone.
Claim 6
Dependent Claim
25 words
Process according to claim 1 wherein the second stream of withdrawn liquid is reacted with ammonium chloride to form a readily separable complex cupr-ammonium salt.
Claim 7
Dependent Claim
29 words
Process according to claim 7 in which the liquid containig the salt complex is chilled substantially below its working temperature to precipitate said salt and thereby regenerate said liquid.
Claim 8
Dependent Claim
77 words
Process according to claim 1 in which a concentrated ferric chloride solution as initial and efficient etchant liquid is maintained at a temperature in the etching zone of about 120* to 130* F and wherein the solution is regenerated when the copper level in said solution reaches about 8 to 9 ounces per gallon, and thereafter withdrawing part of solution and replacing it with solution having a copper content of 0 to about 0.5 ounces per gallon.
Claim 9
Dependent Claim
24 words
Process according to claim 9 in which chlorine is metered substantially continuously to maintain a substantially constant ferric ion content in the etching liquid.
References Cited (Backward Citations)
US3526560A
Cited
US3705061A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-26 | 1977-05-28 | 1977-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-26 | 1981-05-28 | 1981-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-26 | 1985-05-28 | 1985-11-27 | $7700.00 | Window Closed / Lapsed |