Patent US4525246A successfully refreshed from Google Patents.
US4525246A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Making solderable printed circuit boards
Assignee: Hadco Corp
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Filing: 1982-06-24
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Granted: 1985-06-25
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Expires: 2002-06-24
Abstract
Abstract An improved process for making a printed circuit board of the type comprising solder-rooted pads and a solder-coated internal wall of each hole in the circuit board. The new process comprises the step of masking over a dry film, e.g. an alkaline ink film, after copper plating and before solder plating. In one embodiment of the invention, a selectively-plated thin layer of solder to act as a resist except on the areas defined by hole pads and barrels but is wholly free of solder which can melt and cause solder-migration problems under the surface of the printed circuit board.
Inventors
- 👤 Maurice E. Needham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:36
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/30; H05K3/32; H05K3/34; H05K3/3465; H05K3/3473; H05K3/22; H05K3/24; H05K3/243; H05K2203/00; H05K2203/03; H05K2203/0361; H05K2203/04; H05K2203/043; H05K2203/05; H05K2203/0562; H05K2203/0574; H05K2203/07; H05K2203/0703; H05K2203/0723; H05K3/02; H05K3/06; H05K3/061; H05K3/062; H05K3/10; H05K3/108; H05K3/3452; H05K3/40; H05K3/42; H05K3/425; H05K3/427; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49124; Y10T29/49155; Y10T29/49165
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
105 words
In a process for making a copper-circuit-bearing printed circuit board of the solder-compatible type wherein circuit board hole barrels and pads around said holes are coated with a quantity of solder sufficient to facilitate making soldered connections to said printed-circuit board, the improvement wherein a first, thin non-solderable solder layer is electroplated directly over said copper circuit, said first solder layer is covered with a protective mask except in the areas defined by hole pads and hole barrels, and said hole pads and hole barrels are then given a heavier, solder-functional coating of solder before said protective mask is removed from said first solder layer.
Claim 2
Dependent Claim
105 words
In a process for making a copper-circuit-bearing printed circuit board of the solder-compatible type wherein circuit board hole barrels and pads around said holes are coated with a quantity of solder sufficient to facilitate making soldered connections to said printed-circuit board, the improvement wherein a first, thin non-solderable solder layer is electroplated directly over said copper circuit, said first solder layer is covered with a protective mask except in the areas defined by hole pads and hole barrels, and said hole pads and hole barrels are then given a heavier, solder-functional coating of solder before said protective mask is removed from said first solder layer.
Claim 3
Dependent Claim
24 words
A process as defined in claim 1 wherein said first solder layer stripped of said mask is thereafter removed from said printed circuit board.
Claim 4
Dependent Claim
20 words
A process as defined in claim 1 or 2 wherein said first solder layer is less than 0.0003 inches thick.
Claim 5
Dependent Claim
21 words
A process as defined in claim 1 wherein said first solder layer forms a chemically-protective layer and is not readily solderable.
References Cited (Backward Citations)
US2872391A
Cited
US3483615A
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US3673680A
Cited
US3742597A
Cited
US4104111A
Cited
US4304640A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-06-24 | 1988-12-24 | 1989-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-24 | 1992-12-24 | 1993-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-24 | 1996-12-24 | 1997-06-25 | $7700.00 | Window Closed / Lapsed |