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How do I make citric copper plating smooth
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Q. I am using citric copper plating solution to plate copper film on a CVD copper film. the citric copper solution are mainly made of trisodium citrate and copper sulphate, pH is controlled between 4-5 by NaOH and H2SO4. the deposited film is very rough. how do I make this film smooth. thank you very much in advance.
Jingjia Ji- Sydney New South Wales
March 10, 2023
A. Hi Jingjia. I've seen a couple of articles and patents, plus a number of youtube videos, dealing with citric acid [on
eBay or
Amazon] based copper plating ... but I've never seen it actually used for serious purpose. I'm not saying you don't have a good reason, but can I ask why you are using this home-brew rather than a conventional copper sulphate [on
eBay or
Amazon]based copper plating solution?
If the plating is very rough I'd guess that you are plating at too high a current density -- what voltage and amperage per square inch are you using? But there are other causes for roughness like lack of anode bags, lack of filtration, inadequate agitation, or lack of brightener. Do you happen to have a Hull Cell to enable testing your plating solution across a range of current densities? Thanks.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Q. Dear Ted,
Thank you very much for your kind reply. I am developing a less corrosive copper plating solution than sulphate based copper plating solution. it seems Citric base copper solution is a good alternative. However, I don't get film property what I wanted, or too rough surface to be useful. Do you know any brighteners may be applied in the citric based copper plating solution?
thank you very much.
Jingjia
- Sydney New South Wales
March 10, 2023
Miralax
on
Amazon
(affil links)
A. Hi again Jingjia. Hobbyists in youtube videos often suggest polyethylene glycol (Miralax) ⇨
as a brightener for citric-based copper and other plating, but if you are doing serious development work on a marketable plating solution, you should probably do a detailed patent search, plus a thorough technical database search as a starting point.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Dear Ted,
Thank you very much for your suggestions.
- Sydney New South Wales
March 10, 2023
A. Try tartaric acid [on eBay or Amazon] instead citric,There are many patents on tartarate based copper plating solutions( according to old books in 19th century it was used instead cyanide based copper plating solutions ).Hope it helps and good luck!
Goran Budija- Cerovski vrh Croatia
April 2, 2023
"Electro-Deposition of Metals"
by Langbein & Brannt
on
AbeBooks
or
Amazon
(affil links)
A. Weills copper plating solution:
Water 10 quarts, potassium sodium tartrate (Rochelle salt)
[on
eBay or
Amazon]
53 ozs., blue vitriol 10% ozs., 60 per cent,
caustic soda
[affil links]
28 ozs.
(According to G.Langbein ,W.Brandt :ELECTRO-DEPOSITION OF METALS ,New York 1920.,page 417) ⇨
- Cerovski vrh Croatia
April 3, 2023
Hi Goran,
Your suggestions are greatly appreciated. I will try it soon.
- Sydney
April 4, 2023
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