US3998677A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Technique for using solder etch resist in generation of patterns on printed wiring boards
Assignee: AT&T Inc
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Filing: 1974-11-21
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Granted: 1976-12-21
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Expires: 1994-11-21
Abstract
Abstract A technique is described for the generation of a pattern on printed wiring boards bearing a layer of copper. The technique involves the use of a solder cream as an etch resist, the cream comprising a slurry of solder suspended in a curable resin flux. The use of the cream as an etch resist is similar to the use of either ink or solder plate for such purposes. However, the process described is far more economical than currently used techniques and provides a preferred alternative.
Inventors
- 👤 David Verne Anderson
- 👤 Anthony John Cucinotta
- 👤 Donald Lee Durand
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:24
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/02; H; H05; H05K; H05K3/00; H05K3/02; H05K3/06; H05K3/061; H05K3/062; H05K2203/00; H05K2203/04; H05K2203/043; H05K3/10; H05K3/12; H05K3/1216; H05K3/30; H05K3/32; H05K3/34; H05K3/3465; H05K3/3485
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
85 words
A method for etching a copper surface which comprises the steps of a. depositing a resist upon a copper surface in a pattern, exposed copper being destined for etching, the resist being a solder cream comprising a slurry of solder particles suspended in a flux vehicle comprising a rosin, an active hydrogen containing compound and curing agent, the vehicle comprising from 80-85% by weight of the solder cream, b. curing the solder cream at a temperature ranging from 170°-200° F, and c. etching exposed copper.
Claim 2
Independent Claim
85 words
A method for etching a copper surface which comprises the steps of a. depositing a resist upon a copper surface in a pattern, exposed copper being destined for etching, the resist being a solder cream comprising a slurry of solder particles suspended in a flux vehicle comprising a rosin, an active hydrogen containing compound and curing agent, the vehicle comprising from 80-85% by weight of the solder cream, b. curing the solder cream at a temperature ranging from 170°-200° F, and c. etching exposed copper.
Claim 3
Dependent Claim
29 words
Method in accordance with claim 1 wherein the copper surface is a copper clad laminate constructed of at least two layers of porous filler impregnated with a synthetic resin.
Claim 4
Dependent Claim
26 words
A method in accordance with claim 1 wherein the solder particles comprises an alloy of tin and lead containing from 55-70% by weight tin, remainder lead.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-12-21 | 1980-06-21 | 1980-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-12-21 | 1984-06-21 | 1984-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-12-21 | 1988-06-21 | 1988-12-21 | $7700.00 | Window Closed / Lapsed |