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US4377450A
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Palladium electroplating procedure
Assignee: AT&T Inc
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Filing: 1982-04-15
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Granted: 1983-03-22
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Expires: 2002-04-15
Abstract
Abstract A palladium electroplating procedure is described in which the bath is replenished by palladium hydroxide made in a special way. The palladium hydroxide is made by oxidation of palladium diammine dichloride in alkaline aqueous solution using hypochlorite ion as the oxidizing agent. Palladium hydroxide is ideal as a replenishing agent for palladium electroplating baths because it neutralizes hydrogen ions produced in the electroplating process and does not yield anions that accumulate in the bath.
Inventors
- 👤 Yutaka Okinaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:30
CPC Classifications
C; C25; C25D; C25D21/00; C25D21/16; C25D21/18; C01; C01G; C01G55/00; C01G55/004; C25D3/00; C25D3/02; C25D3/50; C01P; C01P2004/00; C01P2004/80
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
80 words
A process for electroplating a metallic substance on a surface, said metallic substance comprising palladium, comprising the step of passing current through a cathode, an electroplating bath and an anode with cathode potential great enough to electroplate palladium and said electrochemical bath having a conductivity greater than 10 -3 mho-cm characterized in that the electroplating bath is replenished by the addition of palladium hydroxide made by the oxidation of palladium diammine dichloride by hypochlorite ion in an alkaline aqueous solution.
Claim 2
Dependent Claim
80 words
A process for electroplating a metallic substance on a surface, said metallic substance comprising palladium, comprising the step of passing current through a cathode, an electroplating bath and an anode with cathode potential great enough to electroplate palladium and said electrochemical bath having a conductivity greater than 10 -3 mho-cm characterized in that the electroplating bath is replenished by the addition of palladium hydroxide made by the oxidation of palladium diammine dichloride by hypochlorite ion in an alkaline aqueous solution.
Claim 3
Dependent Claim
17 words
The process of claim 1 in which the pH of the electroplating bath is greater than 7.
Claim 4
Dependent Claim
17 words
The process of claim 1 in which the source of the hypochlorite ion is an alkali-metal hypochlorite.
Claim 5
Dependent Claim
13 words
The process of claim 3 in which the alkali-metal hypochlorite is sodium hypochlorite.
Claim 6
Dependent Claim
20 words
The process of claim 1 in which the source of hypochlorite ion is chlorine gas bubbled through an aqueous solution.
Claim 7
Dependent Claim
17 words
The process of claim 1 in which the alkaline aqueous solution has a pH greater than 9.
Claim 8
Dependent Claim
17 words
The process of claim 6 in which the pH of the aqueous solution is greater than 11.
Claim 9
Dependent Claim
18 words
The process of claim 7 in which the pH of the aqueous solution is between 13 and 14.
Claim 10
Dependent Claim
53 words
The process of claim 1 in which the oxidation of palladium diammine dichloride is carried out by a procedure comprising the steps of: (a) adding palladium diammine dichloride to an alkaline aqueous solution; (b) adding excess hypochlorite ion in aqueous solution; (c) adding excess hydrogen peroxide solution; and (d) separating the resulting precipitate.
Claim 11
Dependent Claim
25 words
The process of claim 1 in which the palladium hydroxide is kept wet and at room temperature between formation and addition to the electroplating bath.
Claim 12
Dependent Claim
31 words
The process of claim 1 in which the electroplating bath comprises palladium in the form of a complex with at least one organic aliphatic polyamine with 3 to 20 carbon atoms.
Claim 13
Dependent Claim
22 words
The process of claim 11 in which the organic aliphatic polyamines are compounds selected from the group consisting of diaminopropane and diethylenetriamine.
Claim 14
Dependent Claim
13 words
The process of claim 12 in which the organic aliphatic polyamine is 1,3-diaminopropane.
Claim 15
Dependent Claim
18 words
The process of claim 12 in which the pH of the electroplating bath is between 7.5 and 13.5.
Claim 16
Dependent Claim
18 words
The process of claim 14 in which the pH of the electroplating bath is between 11 and 12.5.
Claim 17
Dependent Claim
13 words
The process of claim 1 in which the electroplating bath comprises a buffer.
Claim 18
Dependent Claim
23 words
The process of claim 16 in which the buffer is the hydrogen phosphate-phosphate system with concentration of buffer between 0.1 and 2 molar.
Claim 19
Dependent Claim
20 words
The process of claim 1 in which the electroplating bath temperature during electroplating is between 40 and 60 degrees C.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-03-21 | 1986-09-20 | 1987-03-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-21 | 1990-09-20 | 1991-03-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-21 | 1994-09-20 | 1995-03-22 | $7700.00 | Window Closed / Lapsed |