Patent US4684545A successfully refreshed from Google Patents.
US4684545A
Expired / Lapsed
US
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Electroless plating with bi-level control of dissolved oxygen
Assignee: International Business Machines Corp
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Filing: 1986-02-10
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Granted: 1987-08-04
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Expires: 2006-02-10
Abstract
Abstract Nodule formation in a continuous electroless copper plating system is minimized by independently controlling the dissolved oxygen contents on the plating solution in the bath and in the associated external piping. The level of dissolved oxygen in the plating tank is maintained at a value such that satisfactory plating takes place. At the point where the plating solution leaves the tank, additional oxygen gas is introduced into the solution so that the level of dissolved oxygen in the plating solution in the external piping is high enough to prevent any plating from taking place in the external piping and so that in the external piping the copper is etched or dissolved back into solution. At the end of the external piping, the dissolved oxygen level is reduced so that the dissolved oxygen level of the plating solution in the tank is maintained at the level where plating will take place.
Inventors
- 👤 Edmond O. Fey
- 👤 Peter Haselbauer
- 👤 Dae Y. Jung
- 👤 Ronald A. Kaschak
- 👤 Hans-Dieter Kilthau
- 👤 Roy H. Magnuson
- 👤 Robert J. Wagner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:48
CPC Classifications
C; C23; C23C; C23C18/00; C23C18/16; C23C18/31; C23C18/38; C23C18/40; C23C18/1601; C23C18/1617; C23C18/1633; C23C18/1675; C23C18/1683; H; H05; H05K; H05K3/00; H05K3/10; H05K3/18; H05K3/181; H05K3/187
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
114 words
A method of minimizing the nodules produced by a continuous electroless copper plating system which has a plating solution in a plating tank and in external piping and wherein the oxygen level in the plating tank is maintained at a first value such that plating takes place comprising the steps of: adding oxygen at the point the plating solution enters the external piping so that no plating takes place in the external piping; adjusting the oxygen value in the plating solution to said first value prior to the point the plating solution goes from said external piping to said plating tank; and recirculating the plating solution between said plating tank and said external piping.
Claim 2
Independent Claim
114 words
A method of minimizing the nodules produced by a continuous electroless copper plating system which has a plating solution in a plating tank and in external piping and wherein the oxygen level in the plating tank is maintained at a first value such that plating takes place comprising the steps of: adding oxygen at the point the plating solution enters the external piping so that no plating takes place in the external piping; adjusting the oxygen value in the plating solution to said first value prior to the point the plating solution goes from said external piping to said plating tank; and recirculating the plating solution between said plating tank and said external piping.
Claim 3
Dependent Claim
37 words
The method recited in claim 1 wherein the oxygen value of said plating solution is adjusted prior to the point the plating solution goes from said external piping to said plating tank by the introduction of nitrogen.
Claim 4
Dependent Claim
31 words
The method of claim 1 wherein oxygen is added at the point the plating solution enters the external piping so that etching of said nodules takes place in the external piping.
Claim 5
Dependent Claim
65 words
A continuous electroless plating process for minimizing nodule formation comprising the steps of: maintaining the oxygen level in a plating bath at a first value such that plating takes plate in said bath; and maintaining the oxygen level at a substantially higher than said first value in external piping connected to said bath such that etching of said nodules takes place in said external piping.
Claim 6
Dependent Claim
65 words
A continuous electroless plating process for minimizing nodule formation comprising the steps of: maintaining the oxygen level in a plating bath at a first value such that plating takes plate in said bath; and maintaining the oxygen level at a substantially higher than said first value in external piping connected to said bath such that etching of said nodules takes place in said external piping.
Claim 7
Dependent Claim
20 words
The process of claim 4 additionally comprising the step of recirculating solution between said plating bath and said external piping.
Claim 8
Independent Claim
77 words
A method fo eletrolessly plating circuit lines on printed circuit boards in a plating bath that has associated external piping comprising the steps of: placing said circuit boards in said plating bath; maintaining the oxygen level in said plating bath at an operating point such that copper is deposited on said circuit boards; and maintaining the oxygen level in said external piping at a level such that copper is etched into the solution in said external piping.
Claim 9
Independent Claim
77 words
A method fo eletrolessly plating circuit lines on printed circuit boards in a plating bath that has associated external piping comprising the steps of: placing said circuit boards in said plating bath; maintaining the oxygen level in said plating bath at an operating point such that copper is deposited on said circuit boards; and maintaining the oxygen level in said external piping at a level such that copper is etched into the solution in said external piping.
Claim 10
Independent Claim
120 words
A method of minimizing the nodules produced by an electroless copper plating system which has a plating solution in a plating tank and in external piping and wherein the oxygen level in the plating tank is maintained at a first value such that plating takes place comprising the steps of: adding oxygen at the point the plating solution enters the external piping so that no plating takes place in the external piping; injecting air into said plating solution prior to the point said plating solution goes from said external piping to said plating tank to adjust the oxygen value in the plating solution to said first value; and recirculating the plating solution between said plating tank and said external piping.
Claim 11
Independent Claim
120 words
A method of minimizing the nodules produced by an electroless copper plating system which has a plating solution in a plating tank and in external piping and wherein the oxygen level in the plating tank is maintained at a first value such that plating takes place comprising the steps of: adding oxygen at the point the plating solution enters the external piping so that no plating takes place in the external piping; injecting air into said plating solution prior to the point said plating solution goes from said external piping to said plating tank to adjust the oxygen value in the plating solution to said first value; and recirculating the plating solution between said plating tank and said external piping.
Claim 12
Dependent Claim
31 words
The method of claim 7 wherein oxygen is added at the point the plating solution enters the external piping so that etching of said nodules takes place in the external piping.
References Cited (Backward Citations)
US4162217A
Cited
US4152467A
Cited
US4534797A
Cited
US4525390A
Cited
US4554184A
Cited
US4565575A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-08-03 | 1991-02-02 | 1991-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-03 | 1995-02-02 | 1995-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-03 | 1999-02-02 | 1999-08-04 | $7700.00 | Window Closed / Lapsed |