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Copper plating deposits has nodules
Q. I am a research assistant at the University of Florida and am trying to electroplate copper onto a nickel substrate, from a sulfamate solution of 1.53 M Ni, 0.014 M Cu and 30 grams/liter boric acid, but I am having problems with copper covering the surface on a microscopic scale. The first copper to form always forms in nodules. Is there a problem with copper nucleation on nickel? Is it more difficult for copper to form on nickel than on copper? Is SNAP the answer to our problems?
We are using round 35 mm diameter polycrystalline copper substrates. The pH is 3.5~3.8. The sulfamate solution is commercially pure.Michael Alexander
A. I am sorry that I don't understand the question. Are you trying to plate an alloy of copper and nickel onto a copper substrate using a nickel sulfamate solution containing copper ions?
SNAP is sulfamate nickel anti pit, a proprietary wetting agent, I don't think that is the answer at this point. Is the copper in the sulfamate nickel present in the commercially pure product, or have you added some to the bath?
Falls Township, Pennsylvania
I am with Tom. Are you trying to plate sulfamate nickel with copper in it? If so, why. Copper in more than trace amounts causes a dark junk plate in areas of low current density.
If you are really trying to do this, plate initially at a low current density, about 20 amps per sq ft and then gradually raise it up to final volts and amps. If you do not use a minimum of about 1 volt, you will get immersion (non-adherent) copper plating.
If 20 does not work, try 15 and then 10.James Watts
- Navarre, Florida
Possible causes of "Excess Copper" on Acid Copper plating2007
Q. Hi everyone,
One of our customer encounters excess copper/ roughness problem on their electrolytic copper plating @ high current density (2.8 ASD & above. The Shortest possible time is 65 min. to plate 40 to 45 microns. But one way to arrest this problem is to increase additive concentration up to 5 ml/L in which the recommended is only up to 3 ml/L max.
but on Normal plating condition which is below 2.8 ASD, no excess copper problem occurs. Other chemical components of the solution were ok..
Is there any possible causes related to this problem..
Hope you can help me,..
Than kyou very much in advance...
Plating Shop - Philippines
I would bet the hcd burning is in the hcd area on the part. Assuming that the solution chemistry is all within range, and the bath has been carbon treated recently (within the last 6 mos), Why not try adding the equivalent of 2 ml/l in a hull cell to see if it will reduce the high current density burning on your hull cell panel. Double check with your supplier first. There are various causes for hcd burning, but if time and current have to remain constant, I would concentrate on the "additive" and then investigate further possible causes. Good Luck!
Process Engineer - Syracuse, New York USA
Q. Hi Mark,
Thanks, but my concern here is excess copper and not burning @ HCD..
A. If the part is being rack plated, try in some way to restrict the direct flow of current to the HCD areas, using a PVC shield of some sort or a different rack. In continuous plating we guard the edges of the material to force the current to the middle of the strip before it works itself to the edges. I have also done this in rack plating of large parts. I am not sure what you would do in a barrel if that is where you are having a problem. Good LuckMichael Berrier
- Addison, Illinois, USA
Q. Hi Mr. Michael,
Thanks for the idea..But the excess copper I'm pertaining with is just a very small particle stick on the surface of the PCB & looks like copper,, But this kind of small particle can be removed once you run on the scrubbing machine which is unadvisable due to additional process. I hope you got my point.
Again.. Thank you very much
In your first letter you described roughness when plating @ HCD. This is why I suspected HCD burning. You will also get "excess copper" in this area, because the copper plated thickness will be greater. Now you describe what seem to be nodules, which by the way is not "excess copper", it is particulate matter (debris) in the plating solution. This can be corrected by using clean and stripped racks, changing your filters, and going to a smaller micron rated cartridge such as 5 micron. Second and third causes are improper bath temperature, and too high a brightener concentration. Particulate matter is the subject I would try to correct first.
Process Engineer - Syracuse, New York
May 1, 2017
Q. Hello, we have been experiencing nodules in our 1000 gal acid Cu tank. My first thought is suspended particulates in the solution. Our Engineering manager suspects algae from our RO holding tank. I have seen the platers forget they have the water hose in the tank allowing the solution to rise above the anode baskets disturbing the cupric oxide layer on the 2" anode balls. The anode bags have all been replaced, solution analysis is fine. We also dummy plated at a low CD and filtered through a poly pro filter bag. My two part question is; can algae cause nodules? Can the cupric oxide from the anodes cause nodules? Thank you in advance for your input.Mark Baker
Process Engineering - Phoenix Arizona USA
May 9, 2017
A. Hi Mark
Many years ago in Australia we had drought conditions that lead to low water levels in our storages. Suddenly we started finding we were getting stardusting in nickel finishes that were solved by running filters on the rinse before entry. In this case not nodules but definitely pre rinses can cause problems and this could be proved by running a carbon packed filter on the pre rinse.
I suspect your second thought is more likely and you should be able to try filtering through a 540 filter paper under suction in the lab and examining under low magnification to see if there is particulate matter.
It may mean pumping the whole solution out and filtering back.
- Port Melbourne, Australia