US5232492A
Expired / Lapsed
US
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Electroless gold plating composition
Assignee: Applied Electroless Concepts Inc
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Filing: 1992-01-23
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Granted: 1993-08-03
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Expires: 2012-01-23
Abstract
Abstract An electroless gold plating solution comprising a gold(I) complex, a thiosulfate, a sulfite, a pH regulator and an oxidation controller. The electroless gold plating solution uses a novel reducing agent system, the thiosulfate-sulfite-sulfate system. It shows a plating rate and a plating solution stability comparable to those of conventional gold plating solutions containing borohydride, thiourea, hydrazine, and other reducing agents.
Inventors
- 👤 Gerald A. Krulik
- 👤 Nenad V. Mandich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:52
CPC Classifications
C; C23; C23C; C23C18/00; C23C18/16; C23C18/31; C23C18/42; C23C18/44
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
49 words
An electroless gold plating solution consisting essentially of water, a non-cyanide gold (I) complex selected from the group consisting of a gold sulfite, a gold thiosulfate and mixtures of both, a thiosulfate, a sulfite, and a chelating agent, said solution having a pH adjusted to between 6 and 11.
Claim 2
Dependent Claim
49 words
An electroless gold plating solution consisting essentially of water, a non-cyanide gold (I) complex selected from the group consisting of a gold sulfite, a gold thiosulfate and mixtures of both, a thiosulfate, a sulfite, and a chelating agent, said solution having a pH adjusted to between 6 and 11.
Claim 3
Dependent Claim
19 words
An electroless gold plating solution according to claim 1, wherein said gold(I) concentration is between 0.5 and 60 g/l.
Claim 4
Dependent Claim
19 words
An electroless gold plating solution according to claim 1, wherein said gold(I) concentration is between 1.5 and 15 g/l.
Claim 5
Dependent Claim
21 words
An electroless gold plating solution according to claim 1, wherein the ratio of thiosulfate to gold is from 1/1 to 400/1.
Claim 6
Dependent Claim
21 words
An electroless gold plating solution according to claim 1, wherein the ratio of thiosulfate to gold(I) is from 2/1 to 40/1.
Claim 7
Dependent Claim
21 words
An electroless gold plating solution according to claim 1, wherein the ratio of thiosulfate to sulfite is from 1/50 to 400/1.
Claim 8
Dependent Claim
21 words
An electroless gold plating solution according to claim 1, wherein the ratio of thiosulfate to sulfite is from 1/10 to 200/1.
Claim 9
Dependent Claim
47 words
An electroless gold plating solution according to claim 1, wherein the content of gold(I) complex is 0.0025 to 0.3 moles per liter, the content of the free thiosulfate is 0.01 to 1 moles per liter, and the content of sulfite is 0.001 to 0.5 moles per liter.
References Cited (Backward Citations)
US5106413A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-02 | 1997-02-01 | 1997-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-02 | 2001-02-01 | 2001-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-02 | 2005-02-01 | 2005-08-03 | $7700.00 | Window Closed / Lapsed |