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US4534797A
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Method for providing an electroless copper plating bath in the take mode
Assignee: International Business Machines Corp
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Filing: 1984-01-03
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Granted: 1985-08-13
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Expires: 2004-01-03
Abstract
Abstract An electroless copper plating bath which is in the take mode is provided by determining the amount in the bath of at least four of the components selected from the group of oxygen, reducing agent, cyanide salt, cupric salt, and complexing agent; solving the equation: R=(CABD)/E wherin C is the concentration of cupric salt, A is the concentration of reducing agent, B is the concentration of oxygen, D is the concentration of cyanide salt, E is the concentration of complexing agent, and R is a unitless number. The bath is provided with quantities of the above ingredients so that R in the equation is between about 5 and about 15.
Inventors
- 👤 David E. King
- 👤 Voya Markovich
- 👤 Carlos J. Sambucetti
- 👤 Stephen L. Tisdale
- 👤 Donna J. Trevitt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:27
CPC Classifications
C; C23; C23C; C23C18/00; C23C18/16; C23C18/31; C23C18/38; C23C18/40
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
213 words
A method for providing an electroless copper plating bath in the take mode which comprises: A. determining the amount in said bath of at least four of the components selected from the group of dissolved oxygen, reducing agent selected from the group of formaldehyde, formaldehyde precursors, formaldehyde homopolymers, and mixtures thereof, cyanide ion, cupric ion, and complexing agent; B. solving the following equation: R=(CABD)/E wherein C=concentration of cupric salt in g/l, calculated as CuSO 4 .5H 2 O A=concentration of reducing agent in g/l B=concentration of O 2 , ppm D=concentration of cyanide ion in mg/l, calculated as NaCN E=concentration of complexing agent in g/l C. providing the bath with quantities of said oxygen, reducing agent, cyanide ion source, cupric ion source, and complexing agent so that R, in said equation, is between about 5 and about 15 (g.ppm.mg/(liter) 2 and wherein the amount of said dissolved oxygen is about 0.5-2.0 ppm; amount of said reducing agent is about 2.0-2.5 ml/l calculated as formaldehyde; the amount of said cyanide salt is about 10 to about 12 mg/l, calculated as sodium cyanide; the amount of said cupric salt is about 8.5 to 10 g/l calculated as CuSO 4 .5H 2 O, and the amount of said complexing agent is about 38 to 45 g/l.
Claim 2
Independent Claim
213 words
A method for providing an electroless copper plating bath in the take mode which comprises: A. determining the amount in said bath of at least four of the components selected from the group of dissolved oxygen, reducing agent selected from the group of formaldehyde, formaldehyde precursors, formaldehyde homopolymers, and mixtures thereof, cyanide ion, cupric ion, and complexing agent; B. solving the following equation: R=(CABD)/E wherein C=concentration of cupric salt in g/l, calculated as CuSO 4 .5H 2 O A=concentration of reducing agent in g/l B=concentration of O 2 , ppm D=concentration of cyanide ion in mg/l, calculated as NaCN E=concentration of complexing agent in g/l C. providing the bath with quantities of said oxygen, reducing agent, cyanide ion source, cupric ion source, and complexing agent so that R, in said equation, is between about 5 and about 15 (g.ppm.mg/(liter) 2 and wherein the amount of said dissolved oxygen is about 0.5-2.0 ppm; amount of said reducing agent is about 2.0-2.5 ml/l calculated as formaldehyde; the amount of said cyanide salt is about 10 to about 12 mg/l, calculated as sodium cyanide; the amount of said cupric salt is about 8.5 to 10 g/l calculated as CuSO 4 .5H 2 O, and the amount of said complexing agent is about 38 to 45 g/l.
Claim 3
Dependent Claim
37 words
The method of claim 1 wherein said reducing agent is formaldehyde; said cupric ion source is CuSO 4 .5H 2 O; said cyanide ion source is sodium cyanide; and said complexing agent is ethylene diamine tetraacetic acid.
Claim 4
Dependent Claim
16 words
The method of claim 1 wherein R is about 7 to about 12 (g.ppm.mg/(liter) 2 .
Claim 5
Dependent Claim
10 words
The method of claim 1 wherein R is about 10.
Claim 6
Dependent Claim
32 words
The method of claim 1 wherein the bath has a pH of about 11.6 to about 11.8 and the bath is operated at a temperature of about 70° to about 80° C.
Claim 7
Dependent Claim
20 words
The method of claim 1 wherein the bath is operated at a temperature of about 70° to about 75° C.
Claim 8
Dependent Claim
20 words
The method of claim 1 wherein the bath is operated at a temperature of about 72° to about 74° C.
Claim 9
Dependent Claim
17 words
The method of claim 1 wherein the bath is adjusted by varying the amount of dissolved oxygen.
Claim 10
Dependent Claim
18 words
The method of claim 1 wherein the bath is adjusted by varying the amount of the complexing agent.
Claim 11
Dependent Claim
11 words
The method of claim 1 wherein said reducing agent is formaldehyde.
Claim 12
Dependent Claim
16 words
The method of claim 1 wherein said cupric ion source is CuSO 4 .5H 2 O.
Claim 13
Dependent Claim
12 words
The method of claim 1 wherein cyanide ion source is sodium cyanide.
Claim 14
Dependent Claim
14 words
The method of claim 1 wherein said complexing agent is ethylene diamine tetraacetic acid.
Claim 15
Dependent Claim
15 words
The method of claim 1 wherein said oxygen content is about 1 to 1.5 ppm.
Claim 16
Dependent Claim
15 words
The method of claim 2 wherein said oxygen content is about 1 to 1.5 ppm.
Claim 17
Dependent Claim
16 words
The method of claim 2 wherein R is about 7 to about 12 (g.ppm.mg)/(liter) 2 .
Claim 18
Dependent Claim
15 words
The method of claim 2 wherein R is about 10 to 11 (g.ppm.mg)/1 2 .
Claim 19
Dependent Claim
16 words
The method of claim 1 wherein the specific gravity of the bath is 1.060 to 1.080.
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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) | 1988-08-12 | 1989-02-11 | 1989-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-08-12 | 1993-02-11 | 1993-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-08-12 | 1997-02-11 | 1997-08-13 | $7700.00 | Window Closed / Lapsed |