US3634159A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical circuits assemblies
Assignee: Decca Ltd
•
Filing: 1970-06-24
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Granted: 1972-01-11
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Expires: 1990-06-24
Abstract
Abstract A method of forming a two-dimensional electrical circuit assembly. A substrate is coated with a thin gold layer. The gold layer is removed from marginal areas not associated with the regions of conductive elements and resistive elements of the assembly. The gold layer in the regions of the conductive layers are plated with more gold and the resistive layer in the marginal areas is removed using the gold as a resist. Finally the remaining gold is etched to remove the gold layer from the regions of the resistive elements and to leave gold plating forming the conductive elements.
Inventors
- 👤 William Fletcher Croskery
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 02:27
CPC Classifications
H; H05; H05K; H05K1/00; H05K1/16; H05K1/167; H01; H01C; H01C17/00; H01C17/003; H10; H10N; H10N97/00; H05K2201/00; H05K2201/03; H05K2201/0302; H05K2201/0317; H05K2203/00; H05K2203/03; H05K2203/0361; H05K2203/07; H05K2203/0703; H05K2203/0723; H05K3/00; H05K3/02; H05K3/06; H05K3/061; H05K3/062; H05K3/22; H05K3/24; H05K3/243; H05K3/38; H05K3/388; Y; Y10; Y10S; Y10S428/00; Y10S428/901
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
31 words
A method as claimed in claim 1 in which the plating step includes using said resistive layer to form an electrical connection between All the regions of the desired conductive elements.
Claim 2
Dependent Claim
26 words
A method as claimed in claim 1, comprising also the step of forming an additional intermediate adhesion-improving layer between the resistive layer and said gold layer.
Claim 3
Dependent Claim
22 words
A method as claimed in claim 3 comprising also providing a layer of copper between said intermediate layer and the gold layer.
Claim 4
Dependent Claim
26 words
A method as claimed in claim 1 in which the step of coating the substrate with a resistive layer comprises forming said layer by vacuum deposition.
Claim 5
Dependent Claim
23 words
A method as claimed in claim 1 in which said gold layer is deposited to a thickness of between 2,000 and 4,000 Angstroms.
Claim 6
Dependent Claim
17 words
A method as claimed in claim 6 in which the gold layer is formed by vacuum deposition.
Claim 7
Dependent Claim
48 words
A method as claimed in claim 1 in which the step of selectively removing gold from the marginal areas comprises coating the gold layer with a photoresist, exposing the gold layer through a mask so as to expose the marginal areas for etching, and etching said marginal areas.
Claim 8
Dependent Claim
20 words
A method as claimed in claim 8 in which the etchant comprises a saturated solution of potassium iodide and iodine.
Claim 9
Dependent Claim
54 words
A method as claimed in claim 1 in which the plating step comprises coating the gold layer with a photoresist, exposing the gold layer using a mask so as to develop the photoresist selectively over the region of desired resistive elements, and gold-plating said gold layer in the regions of said desired conductive elements.
Claim 10
Dependent Claim
23 words
A method as claimed in claim 10 in which the gold layer is etched to have a matte surface before it is plated.
Claim 11
Dependent Claim
33 words
A method as claimed in claim 10 in which the plating step comprises also using a plating bath which includes an anode and a cathode and connecting said resistive layer to said cathode.
Claim 12
Dependent Claim
23 words
A method as claimed in claim 1 in which the said etching step comprises etching with a solution of potassium iodide and iodine.
Claim 13
Dependent Claim
19 words
A method as claimed in claim 1 in which the step of selectively removing the resistive layer comprises etching.
References Cited (Backward Citations)
US3217209A
Cited
US3256588A
Cited
US3423205A
Cited
US3423260A
Cited
US3554821A
Cited
US3529350A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-10 | 1975-07-12 | 1976-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-10 | 1979-07-12 | 1980-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-10 | 1983-07-12 | 1984-01-11 | $7700.00 | Window Closed / Lapsed |