Patent US3418227A successfully refreshed from Google Patents.
US3418227A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for fabricating multiple layer circuit boards
Assignee: Texas Instruments Inc
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Filing: 1966-03-31
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Granted: 1968-12-24
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Expires: 1986-03-31
Abstract
No abstract record available.
Inventors
- 👤 Olin B Cecil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:06
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/02; H05K3/06; H05K3/07; H05K1/00; H05K1/02; H05K1/09; H05K3/061; H05K3/062; H05K2201/00; H05K2201/03; H05K2201/0332; H05K2201/0335; H05K2201/0338; H05K2203/00; H05K2203/03; H05K2203/0346; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12535; Y10T428/12556; Y10T428/12569; Y10T428/12736; Y10T428/1275; Y10T428/12771; Y10T428/12861; Y10T428/12937
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
113 words
IN A PROCESS FOR FABRICATING A CIRCUIT BOARD FROM STARTING MATERIAL COMPRISED ON A ONCONDUCTIVE BASE AND MULTIPLE LAYERS OF METALLIC FOILS THE OUTER LAYER OF FOIL HAVING A SLOWER ETCH RATE THAN THE ADJACENT UNDERLYING LAYER OF FOIL, THE STEPS OF SELECTIVELY ETCHING THE METALLIC FOILS TO LEAVE CONDUCTOR STRIPS ON THE BASE SHEET HAVING AN OVERHANGING LIP AS A RESULT OF THE FASTER ETCH RATE OF THE UNDERLYING LAYER OF FOIL, AND IMMERSING THE CONDUCTOR STRIPS IN AN ELECTROCHEMICAL ETCHANT AND PASSING A CURRENT BETWEEN THE CONDUCTOR STRIPS AND THE ELECTROCHEMICAL ETCHANT TO SELECTIVELY REMOVE THE OVERHANGING LIP AS THE RESULT OF A CONCENTRATION OF THE CURRENT IN THE OVERHANGING LIP.
Claim 2
Dependent Claim
113 words
IN A PROCESS FOR FABRICATING A CIRCUIT BOARD FROM STARTING MATERIAL COMPRISED ON A ONCONDUCTIVE BASE AND MULTIPLE LAYERS OF METALLIC FOILS THE OUTER LAYER OF FOIL HAVING A SLOWER ETCH RATE THAN THE ADJACENT UNDERLYING LAYER OF FOIL, THE STEPS OF SELECTIVELY ETCHING THE METALLIC FOILS TO LEAVE CONDUCTOR STRIPS ON THE BASE SHEET HAVING AN OVERHANGING LIP AS A RESULT OF THE FASTER ETCH RATE OF THE UNDERLYING LAYER OF FOIL, AND IMMERSING THE CONDUCTOR STRIPS IN AN ELECTROCHEMICAL ETCHANT AND PASSING A CURRENT BETWEEN THE CONDUCTOR STRIPS AND THE ELECTROCHEMICAL ETCHANT TO SELECTIVELY REMOVE THE OVERHANGING LIP AS THE RESULT OF A CONCENTRATION OF THE CURRENT IN THE OVERHANGING LIP.
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) | 1971-12-24 | 1972-06-24 | 1972-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-12-24 | 1976-06-24 | 1976-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-12-24 | 1980-06-24 | 1980-12-24 | $7700.00 | Window Closed / Lapsed |