US4483906A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Copper foil for a printed circuit and a method for the production thereof
Assignee: Furukawa Circuit Foil Co Ltd
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Filing: 1983-03-18
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Granted: 1984-11-20
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Expires: 2003-03-18
Abstract
Abstract Copper foil for printed circuits which comprises a copper layer and a nickel layer formed on one or both sides of said copper layer, the surface of said nickel layer having been subjected to a cathodic chromic acid treatment, and a method for producing the same. Said copper foil can be etched easily and completely with ammonium persulfate solution or with a cupric chloride solution, and is free from so called undercutting phenomenon. A further advantage of printed circuits prepared with said copper foil is that the exposed resin substrate is not stained and the copper foil is strongly adhered to the substrate before and after heating.
Inventors
- 👤 Hiroshi Nakatsugawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:13
CPC Classifications
C; C25; C25D; C25D5/00; C25D5/10; C25D5/12; C25D11/00; C25D11/38; C25D5/627; H; H05; H05K; H05K3/00; H05K3/38; H05K3/382; H05K3/384; H05K2201/00; H05K2201/03; H05K2201/0332; H05K2201/0335; H05K2201/0355; H05K2203/00; H05K2203/07; H05K2203/0703; H05K2203/0723; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/923; Y10S428/924; Y10S428/926; Y10S428/9335; Y10S428/934; Y10S428/935; Y10T; Y10T428/00; Y10T428/12; Y10T428/12431; Y10T428/12438; Y10T428/12493; Y10T428/12535; Y10T428/12611; Y10T428/12771; Y10T428/12861; Y10T428/12903; Y10T428/1291
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
149 words
An improved composite copper foil useful in the manufacture of printed circuits comprising a copper foil layer and at least one nickel layer which is substantially sulfur-free, said nickel layer being integral with and coating at least one surface of said copper foil, the improvement comprising said composite copper foil coated with said nickel layer having been immersed in and said nickel layer cathodically electrolized in a chromic acid bath to treat the surface of said nickel layer so that said composite foil becomes readily and completely removable by etching in ammonium persulfate etchant, said chromic acid bath consisting essentially of an aqueous solution of chromic acid or an aqueous solution of an alkali metal salt or an ammonium salt of chromic acid or dichromic acid, and said nickel foil having a thickness of from 0.002 to 0.8 micron prior to having been immersed in said chromic acid bath.
Claim 2
Dependent Claim
149 words
An improved composite copper foil useful in the manufacture of printed circuits comprising a copper foil layer and at least one nickel layer which is substantially sulfur-free, said nickel layer being integral with and coating at least one surface of said copper foil, the improvement comprising said composite copper foil coated with said nickel layer having been immersed in and said nickel layer cathodically electrolized in a chromic acid bath to treat the surface of said nickel layer so that said composite foil becomes readily and completely removable by etching in ammonium persulfate etchant, said chromic acid bath consisting essentially of an aqueous solution of chromic acid or an aqueous solution of an alkali metal salt or an ammonium salt of chromic acid or dichromic acid, and said nickel foil having a thickness of from 0.002 to 0.8 micron prior to having been immersed in said chromic acid bath.
Claim 3
Dependent Claim
23 words
The copper foil of claim 1 wherein said nickel layer prior to said immersion has a thickness of from 0.02 to 0.2 micron.
References Cited (Backward Citations)
US3585010A
Cited
US3857681A
Cited
US3781596A
Cited
US3981691A
Cited
US4088544A
Cited
US4260449A
Cited
US4311768A
Cited
JPS55102288A
Cited
US4376154A
Cited
US4386139A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-11-20 | 1988-05-21 | 1988-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-20 | 1992-05-21 | 1992-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-20 | 1996-05-21 | 1996-11-20 | $7700.00 | Window Closed / Lapsed |