US3904783A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for forming a printed circuit
Assignee: NTT Inc
•
Filing: 1974-03-20
•
Granted: 1975-09-09
•
Expires: 1994-03-20
Abstract
Abstract A method for forming a printed circuit is disclosed. The method comprises coating the surface of an insulating substrate with a solution of metal salts of organic acids in a mixed solvent consisting of alcohol, water and ammonia to form a photosensitive layer consisting of said metal salts thereon, irradiating the desired portions of the layer with ultraviolet rays so as to deposit the metal on a pattern of a desired circuit, developing and fixing the deposited metal, and carrying out the plating on the pattern, whereby the deposited metal functions as the nuclei for the plating.
Inventors
- 👤 Shigeo Nara
- 👤 Kentaro Matsuyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 00:30
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/10; H05K3/18; H05K3/181; H05K3/182; H05K3/185; C; C23; C23C; C23C18/00; C23C18/16; C23C18/1601; C23C18/1603; C23C18/1607; C23C18/1608; C23C18/1612; G; G03; G03C; G03C1/00; G03C1/494; G03C1/498; G03C1/49881; G03C1/50; G03C1/64; G03C1/705; G03C5/00; G03C5/58; H05K3/40; H05K3/42; H05K3/425; H05K3/426
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
151 words
IN THE METHOD OF FORMING A PRINTED CIRCUIT BY COATING A METAL ORGANIC SALT ON AN INSULTING SUBSTRATE, ACTIVATING SAID METAL SALT BY ULTRAVIOLET RAYS SO AS TO DEPOSIT A METAL ON THE INSULTING SUBSTRATE AND SUBSEQUENTLY ELECTROLESSLY METALLIZING THEREON, THE IMPROVEMENT WHICH COMPRISES COATING THE SURFACE OF THE INSULTING SUBSTRATE WITH A SOLUTION OF SILVER GLUTAMATE IN ADMIXED SOLVENT SELECTED FROM THE GROUP CONSISTING OF AN ALCOHOL-WATER AMMONIA MIXTURE AND AN ALCHOL-WATERETHYLENE DIAMINE MIXTURE, TO FORM A PHOTOSENSITIVE LAYER OF SAID SILVER GLUTAMATE THEREON, IRRADIATING THE DESIRED PORTIONS OF SAID LAYER WITH ULTRAVIOLET RAYS HAVING A WAVE LENGTH SHORTER THAN 35MU AND IN A QUALITY OF IRRADIATED LIGHT OF AT LEAST 8 X 10**7 ERG/CM SO AS TO DEPOSIT SILVER METAL AT THE DESIRED PORTIONS, REMORVING THE NON-IRRADICATED SILVER GLUTAMATE AND ORGANIC ACID LIBERATED BY IRRADICATION, AND CARRYING OUT THE ELECTROLESS PLANTING UTILIZING THE DEPOSITE SILVER AS THE PLATING NUCLEI.
Claim 2
Dependent Claim
151 words
IN THE METHOD OF FORMING A PRINTED CIRCUIT BY COATING A METAL ORGANIC SALT ON AN INSULTING SUBSTRATE, ACTIVATING SAID METAL SALT BY ULTRAVIOLET RAYS SO AS TO DEPOSIT A METAL ON THE INSULTING SUBSTRATE AND SUBSEQUENTLY ELECTROLESSLY METALLIZING THEREON, THE IMPROVEMENT WHICH COMPRISES COATING THE SURFACE OF THE INSULTING SUBSTRATE WITH A SOLUTION OF SILVER GLUTAMATE IN ADMIXED SOLVENT SELECTED FROM THE GROUP CONSISTING OF AN ALCOHOL-WATER AMMONIA MIXTURE AND AN ALCHOL-WATERETHYLENE DIAMINE MIXTURE, TO FORM A PHOTOSENSITIVE LAYER OF SAID SILVER GLUTAMATE THEREON, IRRADIATING THE DESIRED PORTIONS OF SAID LAYER WITH ULTRAVIOLET RAYS HAVING A WAVE LENGTH SHORTER THAN 35MU AND IN A QUALITY OF IRRADIATED LIGHT OF AT LEAST 8 X 10**7 ERG/CM SO AS TO DEPOSIT SILVER METAL AT THE DESIRED PORTIONS, REMORVING THE NON-IRRADICATED SILVER GLUTAMATE AND ORGANIC ACID LIBERATED BY IRRADICATION, AND CARRYING OUT THE ELECTROLESS PLANTING UTILIZING THE DEPOSITE SILVER AS THE PLATING NUCLEI.
Claim 3
Dependent Claim
15 words
A method as claimed in claim 1, wherein the photosensitive layer contains a binding material.
Claim 4
Dependent Claim
25 words
A METHOD AS CLAIMED IN CLAIM 2, WHEREIN REMOVAL OF NON-IRRADIATED SILVER GLUTAMATE AND LIBERATED GLUTAMIC ACID ARE CARRIED OUT BY USING SAID MIXED SOLVENT.
Claim 5
Dependent Claim
23 words
A method as claimed in claim 2, wherein the binding material is selected from the group consisting of epoxy resin and dichromate-gelatin mixture.
Claim 6
Dependent Claim
25 words
A method as claimed in claim 1, wherein removal of non-irradiated silver glutamate and liberated glutamic acid are carried out by using said mixed solvent.
References Cited (Backward Citations)
US3227553A
Cited
US3492151A
Cited
US3719490A
Cited
US3647450A
Cited
US3562005A
Cited
US3615457A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-08 | 1979-03-10 | 1979-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-08 | 1983-03-10 | 1983-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-08 | 1987-03-10 | 1987-09-09 | $7700.00 | Window Closed / Lapsed |