US3926699A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing printed circuit boards with terminal tabs
Assignee: Rbp Chemical Corp
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Filing: 1974-12-18
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Granted: 1975-12-16
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Expires: 1994-12-18
Abstract
Abstract A method for rapidly stripping solder or tin from a substrate, such as copper, without adversely affecting the substrate in the preparation of circuit boards having terminal tabs. The composition comprises hydrofluoric acid or salts thereof, ammonia and an oxygen source such as hydrogen peroxide. The use of a soluble metal complexer peroxide stabilizer enables use of larger percentages of fluoride and peroxide to materially increase the life and capacity of the product. The composition is especially useful in a process of rapidly stripping solder from copper terminal tabs of a printed circuit board, following which the exposed copper tab is plated with a more noble metal.
Inventors
- 👤 Charles H Dixon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:59
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/02; H05K3/06; H05K3/067; C; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/16; C23F1/30; C23F1/44
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
116 words
THE METHOD OF RAPIDLY STRIPPING A LAYER OF METAL SELECTED FROM THE GROUP CONSISTING OF LEAD-TIN SOLDER AND TIN FROM A LAYER OF COPPER ON A FIBERGLASS CIRCUIT BOARD WITHOUT ADVERSELY AFFECTING THE COPPER AND FIBERGLASS, SAID PROCESS COMPRISING THE STEPS OF: EXPOSING THE SOLDER TO A COMPOSITION COMPRISING AMMONIUM BIFLUORIDE IN THE RANGE OF 10% TO 25% BY WEIGHTR, AND HYDROGEN PEROXIDE IN THE RANGE OF 1% TO 5% BY WEIGHT, AND WATER IN THE RANGE OF 89% TO 70% BY WEIGHT FOR A TIME SUFFICIENT TO REMOVE THE SOLDER, AND RINSING THE SAID COMPSITION FROM THE COPPER AFTER THE SOLDER HAS BEEN EFFECTIVELY STRIPPED AND BEFORE THE COPPER AND PLASTIC HAVE BEEN ADVERSELY AFFECTED.
Claim 2
Independent Claim
116 words
THE METHOD OF RAPIDLY STRIPPING A LAYER OF METAL SELECTED FROM THE GROUP CONSISTING OF LEAD-TIN SOLDER AND TIN FROM A LAYER OF COPPER ON A FIBERGLASS CIRCUIT BOARD WITHOUT ADVERSELY AFFECTING THE COPPER AND FIBERGLASS, SAID PROCESS COMPRISING THE STEPS OF: EXPOSING THE SOLDER TO A COMPOSITION COMPRISING AMMONIUM BIFLUORIDE IN THE RANGE OF 10% TO 25% BY WEIGHTR, AND HYDROGEN PEROXIDE IN THE RANGE OF 1% TO 5% BY WEIGHT, AND WATER IN THE RANGE OF 89% TO 70% BY WEIGHT FOR A TIME SUFFICIENT TO REMOVE THE SOLDER, AND RINSING THE SAID COMPSITION FROM THE COPPER AFTER THE SOLDER HAS BEEN EFFECTIVELY STRIPPED AND BEFORE THE COPPER AND PLASTIC HAVE BEEN ADVERSELY AFFECTED.
Claim 3
Dependent Claim
19 words
The method of claim 1 wherein the solder has a composition of 60 parts tin and 40 parts lead.
Claim 4
Dependent Claim
21 words
The method of claim 1 wherein the layer of copper includes terminal tab portions adapted for connection to an ancillary circuit.
Claim 5
Independent Claim
121 words
The method of rapidly stripping a layer of metal selected from the group consisting of lead-tin solder and tin from a layer of copper on a plastic resin circuit board without adversely affecting the copper and board, said process comprising the steps of: exposing the solder to a composition comprising ammonium bifluoride in the range of 5% to 50% by weight, hydrogen peroxide in the range of 1% to 35% by weight, a soluble metal complexer inhibitor of 0.1% to 10% by weight, and the balance of water for a time sufficient to remove the solder, and rinsing the said composition from the copper after the solder has been effectively stripped and before the copper and board have been adversely affected.
Claim 6
Independent Claim
121 words
The method of rapidly stripping a layer of metal selected from the group consisting of lead-tin solder and tin from a layer of copper on a plastic resin circuit board without adversely affecting the copper and board, said process comprising the steps of: exposing the solder to a composition comprising ammonium bifluoride in the range of 5% to 50% by weight, hydrogen peroxide in the range of 1% to 35% by weight, a soluble metal complexer inhibitor of 0.1% to 10% by weight, and the balance of water for a time sufficient to remove the solder, and rinsing the said composition from the copper after the solder has been effectively stripped and before the copper and board have been adversely affected.
Claim 7
Dependent Claim
21 words
The method of claim 4 wherein the layer of copper includes terminal tab portions adapted for connection to an ancillary circuit.
Claim 8
Dependent Claim
31 words
The method of claim 4 wherein said metal complexer inhibitor comprises triisopropanolamine of 0.1% to 5.0% by weight and 0.1% to 5% by weight of a 75% acid equivalent phosphate complex.
Claim 9
Independent Claim
110 words
The method of rapidly stripping a layer of metal selected from the group consisting of lead-tin solder and tin from a layer of copper on a plastic resin circuit board without adversely affecting the copper and board, said process comprising the steps of: exposing the solder to a composition comprising ammonium bifluoride in the range of 5% to 50% by weight, hydrogen peroxide in the range of 1% to 35% by weight and the balance of water for a time sufficient to remove the solder, and rinsing the said composition from the copper after the solder has been effectively stripped and before the copper and board have been adversely affected.
Claim 10
Independent Claim
110 words
The method of rapidly stripping a layer of metal selected from the group consisting of lead-tin solder and tin from a layer of copper on a plastic resin circuit board without adversely affecting the copper and board, said process comprising the steps of: exposing the solder to a composition comprising ammonium bifluoride in the range of 5% to 50% by weight, hydrogen peroxide in the range of 1% to 35% by weight and the balance of water for a time sufficient to remove the solder, and rinsing the said composition from the copper after the solder has been effectively stripped and before the copper and board have been adversely affected.
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) | 1978-12-15 | 1979-06-16 | 1979-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-15 | 1983-06-16 | 1983-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-15 | 1987-06-16 | 1987-12-16 | $7700.00 | Window Closed / Lapsed |