Claims
- 1. A single tank recirculating electroless copper plating system comprising:
- a plating tank having an input port and output port;
- a plating solution in said plating tank wherein oxygen is maintained at an operating point such that copper plating takes place;
- pumping means, connected to said output port, for recirculating said plating solution by continuously forcing said plating solution directly from said plating tank into external recirculation piping, said external recirculation piping having a volume less than said plating tank and containing
- an oxygen feed controller, disposed downstream from said pumping means, to introduce oxygen for switching said plating solution from the copper plating operating point to a non-plating operating point within said recirculation piping, such that plating does not take place in said external recirculation piping and nodules present in the plating solution in the external recirculation piping are etched back into solution,
- chemical maintenance means, disposed downstream from said oxygen feed controller, for introducing chemicals into said plating solution in said recirculation piping to maintain plating solution chemicals at a desired level, and
- feed controller means, disposed downstream from said chemical maintenance means and upstream from said input port, for switching said plating solution from the non-plating operating point to the copper plating operating point before the plating solution reenters said plating tank.
- 2. A single tank recirculating electroless copper plating system of claim 1 wherein said feed controller means introduces air to switch said plating solution from a non-plating operating point to a copper plating operating point.
Parent Case Info
This is a continuation of Ser. No. 034,241, filed 4/6/87 now abandoned, which is a division of co-pending application Ser. No. 827,427, filed on Feb. 10, 1986, now abandoned.
US Referenced Citations (16)
Foreign Referenced Citations (2)
Number |
Date |
Country |
0169764 |
Dec 1981 |
JPX |
0155679 |
Aug 1985 |
JPX |
Divisions (1)
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Number |
Date |
Country |
Parent |
827427 |
Feb 1986 |
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Continuations (1)
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Number |
Date |
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Parent |
34241 |
Apr 1987 |
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