Patent US4666739A successfully refreshed from Google Patents.
US4666739A
Expired / Lapsed
US
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Process for the production of metal patterns on insulating substrates as well as insulating substrates with metal patterns, especially printed circuits
Assignee: MAX SCHLOTTER & Co KG DR-ING GmbH
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Filing: 1985-05-06
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Granted: 1987-05-19
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Expires: 2005-05-06
Abstract
Abstract A process is described for the production of metal patterns on insulating substrates, especially of printed circuits, in which the substrates are provided with holes by means of electrical connections and the metal patterns are produced on the surface of the substrate with the aid of a negative mask in accordance with the subtractive process, said process being characterized by the following steps: treatment in gaseous sulfur trioxide; application of a negative mask which corresponds to the conductive pattern to be produced; through-hole-plating and subsequent plating of the conductive pattern, which is effected by the following steps in the process: activation by means of an ionogenic precious metal solution, treatment in a reducing agent solution, chemical or chemical and electrolytic deposit, in which the metal deposit takes place solely on the surface of the metal pattern which is to be produced. In addition, insulating substrates with metal patterns, especially printed circuits, are disclosed.
Inventors
- 👤 Jiri Roubal
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:09
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/40; H05K3/42; H05K3/38; H05K3/381; H05K3/422; H05K2203/00; H05K2203/08; H05K2203/087; H05K3/425; H05K3/427
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
158 words
A process for the production of metal patterns on a metal-clad insulating substrate in which said substrate is provided with holes for electrical connection and the metal patterns are produced on the surface of said substrate with the aid of a negative mask according to the substractive process, said process comprising the steps of: (i) treating said substrate with gaseous sulfur trioxide; (ii) applying a negative mask to the sulfur trioxide treated substrate, said negative mask corresponding to the negative image of the conductive pattern to be produced; (iii) activating said substrate by treatment with an ionogenic palladium activating solution having a pH in the range of from 1 to 7; (iv) treating said substrate with a reducing agent solution; and (v) chemically or chemically and electrochemically depositing metal on said substrate, said metal being selectively deposited on the surface of the metal pattern to be produced and on the walls of said holes provided for electrical connection.
Claim 2
Dependent Claim
158 words
A process for the production of metal patterns on a metal-clad insulating substrate in which said substrate is provided with holes for electrical connection and the metal patterns are produced on the surface of said substrate with the aid of a negative mask according to the substractive process, said process comprising the steps of: (i) treating said substrate with gaseous sulfur trioxide; (ii) applying a negative mask to the sulfur trioxide treated substrate, said negative mask corresponding to the negative image of the conductive pattern to be produced; (iii) activating said substrate by treatment with an ionogenic palladium activating solution having a pH in the range of from 1 to 7; (iv) treating said substrate with a reducing agent solution; and (v) chemically or chemically and electrochemically depositing metal on said substrate, said metal being selectively deposited on the surface of the metal pattern to be produced and on the walls of said holes provided for electrical connection.
Claim 3
Dependent Claim
36 words
Process as in claim 1, wherein during the treatment sulfur trioxide in concentrations of 10 mg/l up to concentrations which correspond to the vapor pressure of sulfur trioxide over 65% oleum at 25° C. is used.
Claim 4
Dependent Claim
19 words
Process as in claim 1, wherein the treatment in gaseous sulfur trioxide lasts from 1 second to 20 minutes.
Claim 5
Dependent Claim
19 words
Process as in claim 1, wherein the negative mask is produced by means of photoresist or by screen printing.
Claim 6
Dependent Claim
20 words
Process as in claim 1, wherein one or more compounds which contain basic nitrogen are added to said activating solution.
Claim 7
Dependent Claim
32 words
Process as in claim 5, wherein the ratio of the molar concentration of the compound containing nitrogen, based on nitrogen, to the molar concentration of the palladium salt is at least 2.
Claim 8
Dependent Claim
12 words
Process as in claim 5, wherein the activating solution contains ammonium ions.
Claim 9
Dependent Claim
15 words
Process as in claim 5, wherein the activating solution contains primary, secondary or tertiary amines.
Claim 10
Dependent Claim
21 words
Process as in claim 5, wherein the pH value of the activating solution is adjusted to be from 2 to 3.
Claim 11
Dependent Claim
13 words
Process as in claim 1, wherein the reducing agent solution contains aminoborane compounds.
Claim 12
Dependent Claim
12 words
Process as in claim 10, wherein the reducing agent solution contains dimethylaminoborane.
Claim 13
Dependent Claim
22 words
Process as in claim 1, wherein as the negative mask, solvent soluble or alkali soluble photoresists or screen printing inks are used.
Claim 14
Dependent Claim
17 words
Process as in claim 1, wherein as the chemical deposition bath, a chemical nickel bath is used.
Claim 15
Dependent Claim
16 words
Process as in claim 13, wherein the chemical nickel bath contains aminoborane as the reducing agent.
Claim 16
Dependent Claim
12 words
Process as in claim 13, wherein the chemical nickel bath contains dimethylaminoborane.
Claim 17
Dependent Claim
20 words
Process as in claim 13, wherein the pH value of the chemical nickel bath is set between 5 and 7.
Claim 18
Dependent Claim
15 words
Process as in claim 1 wherein said metal-clad insulating substrate is a printed circuit board.
Claim 19
Dependent Claim
19 words
Process as in claim 1, wherein the treatment in gaseous sulfur trioxide lasts from 5 seconds to 5 minutes.
References Cited (Backward Citations)
US4039714A
Cited
US4285991A
Cited
US4308301A
Cited
EP0044878A1
Cited
US4325780A
Cited
DE3146164A1
Cited
US4520046A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-05-18 | 1990-11-17 | 1991-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-18 | 1994-11-17 | 1995-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-18 | 1998-11-17 | 1999-05-19 | $7700.00 | Window Closed / Lapsed |