US4830668A
Expired / Lapsed
US
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Acidic bath for electroless deposition of gold films
Assignee: WC Heraus GmbH and Co KG
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Filing: 1987-12-08
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Granted: 1989-05-16
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Expires: 2007-12-08
Abstract
Abstract In an aqueous bath for electroless deposition of gold films, of the type containing a source of gold in oxidized form, a reducing agent, a stabilizer of 2-mercaptobenzothiazole or a derivative thereof, the improvement comprising said source of gold being a gold complex which is the reaction product of an alkali metal cyanoaurate (III) and a complexing agent selected from the group consisting of ethylenediaminetetramethylene-phosphonic acid and 1-hydroxythane-1,1-diphosphonic acid in aqueous solution; said aqueous bath having a pH value between 0.2 and 1.8.
Inventors
- 👤 Konrad Wundt
- 👤 Burkhard Mankau
- 👤 Jutta Schaad
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:36
CPC Classifications
C; C23; C23C; C23C18/00; C23C18/16; C23C18/31; C23C18/42; C23C18/44
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
97 words
In an aqueous bath, for electroless deposition of gold films, of the type containing a source of gold in oxidized form, a reducing agent, and a stabilizer of 2-mercaptobenzothiazole or a derivative thereof, the improvement comprising said source of gold being an aqueous solution of a gold complex which is formed by reacting an alkali metal cyanoaurate (III) or ammonium cyanoaurate (III) and a complexing agent selected from the group consisting of ethylenediaminetetra-methylenephosphonic acid and 1-hydroxyethane-1, 1-diphosphonic acid, for at least 24 hours at room temperature; said aqueous bath having a pH value between 0.2 and 1.8.
Claim 2
Dependent Claim
97 words
In an aqueous bath, for electroless deposition of gold films, of the type containing a source of gold in oxidized form, a reducing agent, and a stabilizer of 2-mercaptobenzothiazole or a derivative thereof, the improvement comprising said source of gold being an aqueous solution of a gold complex which is formed by reacting an alkali metal cyanoaurate (III) or ammonium cyanoaurate (III) and a complexing agent selected from the group consisting of ethylenediaminetetra-methylenephosphonic acid and 1-hydroxyethane-1, 1-diphosphonic acid, for at least 24 hours at room temperature; said aqueous bath having a pH value between 0.2 and 1.8.
Claim 3
Dependent Claim
24 words
The bath of claim 1 wherein the aqueous solution is heated to about 80° C. and then allowed to cool to said room temperature.
Claim 4
Dependent Claim
14 words
The bath of claim 1 having a working temperature between 85° and 100° C.
Claim 5
Dependent Claim
44 words
The bath of claim 1, wherein said complex is formed from said aqueous solution containing from 0.5 to 15 g/l of gold in the form of an alkali metal cyanoaurate(III) or of ammonium cyanoaurate(III) and from 2.5 to 45 g/l of the complexing agent.
Claim 6
Dependent Claim
40 words
The bath of claim 4, wherein from 1 to 10 g/l of gold in the form of alkali metal cyanoaurate(III) or of ammonium cyanoaurate(III) and from 7.5 to 20 g/l of the complexing agent are used to form said complex.
Claim 7
Dependent Claim
15 words
The bath of claim 1 further comprising 0.1 to 5 g/l of a wetting agent.
Claim 8
Dependent Claim
12 words
The bath according to claim 1, wherein the aqueous solution is acidic.
Claim 9
Dependent Claim
15 words
The bath of claim 7, wherein the aqueous solution contains hydrochloric acid or citric acid.
Claim 10
Dependent Claim
12 words
The bath of claim 1, wherein said reducing agent is a hypophosphite.
Claim 11
Dependent Claim
36 words
The bath of claim 1, wherein the aqueous solution contains potassium cyanoaurate(III) or ammonium cyanoaurate(III) and ethylenediaminetetra-methylenephosphonic acid, and the reducing agent is sodium hypophosphite and the stabilizer is the sodium salt of 2-mercaptobenzothiazole-S-propane sulfonic acid.
Claim 12
Dependent Claim
11 words
The bath of claim 10, wherein the potassium cyanoaurate(III) is used.
Claim 13
Dependent Claim
30 words
The bath of claim 1, wherein the aqueous solution contains potassium cyanoaurate(III) or ammonium cyanoaurate(III) and 1-hydroxyethane-1,1-diphosphonic acid and the reducing agent is sodium hypophosphite and the stabilizer is 2-mercaptobenzothiazole.
Claim 14
Dependent Claim
11 words
The bath of claim 12, wherein the potassium cyanoaurate(III) is used.
Claim 15
Dependent Claim
11 words
The bath of claim 1, wherein the ammonium cyanoaurate(III) is used.
Claim 16
Dependent Claim
14 words
The bath of claim 1, wherein the aqueous solution contains sodium or potassium cyanoaurate(III).
Claim 17
Dependent Claim
11 words
The bath of claim 15, wherein the bath contains potassium cyanoaurate(III).
Claim 18
Dependent Claim
12 words
The bath of claim 1, wherein the alkali metal cyanoaurate(III) is used.
Claim 19
Dependent Claim
89 words
In an aqueous bath for electroless deposition of gold films, of the type containing a source of gold in oxidized form, a reducing agent and a stabilizer of 2-mercaptobenzothiazole or a derivative thereof, the improvement comprising said source of gold being an aqueous solution of a gold complex which is the reaction product of an alkali metal cyanoaurate (III) or ammonium cyanoaurate (III) and a complexing agent selected from the group consisting of ethylenediaminetetra-methylenephosphonic acid and 1-hydroxyethane-1,1-diphosphonic acid; said aqueous bath having a pH value between 0.2 and 1.8.
Claim 20
Dependent Claim
89 words
In an aqueous bath for electroless deposition of gold films, of the type containing a source of gold in oxidized form, a reducing agent and a stabilizer of 2-mercaptobenzothiazole or a derivative thereof, the improvement comprising said source of gold being an aqueous solution of a gold complex which is the reaction product of an alkali metal cyanoaurate (III) or ammonium cyanoaurate (III) and a complexing agent selected from the group consisting of ethylenediaminetetra-methylenephosphonic acid and 1-hydroxyethane-1,1-diphosphonic acid; said aqueous bath having a pH value between 0.2 and 1.8.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-05-15 | 1992-11-14 | 1993-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-15 | 1996-11-14 | 1997-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-15 | 2000-11-14 | 2001-05-16 | $7700.00 | Window Closed / Lapsed |