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Cleaning Electroplated Solder

Dennis Fall

#10029

Cleaning Electroplated Solder | 20 August, 1999

I have a layer of electroplated solder (10/90) that appeares to have some sort of contaminent on it. Water will not wet to the layer in some areas. I have tried using 10% HCl in DI as a cleaner as well as 7.5% Fluoboric acid in DI. Neither has touched the contaminent. Is there another suggestion for a cleaner? What I am really hoping to find is a non-proprietary type of chemistry/process. Thank you, Dennis Fall

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Brian

#10030

Re: Cleaning Electroplated Solder | 21 August, 1999

| I have a layer of electroplated solder (10/90) that appeares to have some sort of contaminent on it. Water will not wet to the layer in some areas. I have tried using 10% HCl in DI as a cleaner as well as 7.5% Fluoboric acid in DI. Neither has touched the contaminent. Is there another suggestion for a cleaner? What I am really hoping to find is a non-proprietary type of chemistry/process. | Thank you, | Dennis Fall | Nasty one!

If fluoboric acid won't touch it, then it sounds as if you have some organic brighteners or some such co-deposited with the Sn/Pb. Unfortunately, Sn/Pb electroplating baths have all sorts of additives which cause problems. Must admit I have never heard of 10/90 being used on PCBs and I suspect you may also have the start of the lead/lead oxide/lead carbonate cycle, as it is so lead-rich. My best guess for a non proprietary mix would be to treat it with 5% fluoboric, 1% disodium EDTA and 2% of a decent anionic detergent that can stand the acid, with hand-scrubbing with a stiff NON-abrasive brush in it, followed by some VERY good water wash/rinse. If this does not do the trick, try scrubbing with a strong solvent (e.g. trichloroethylene !!! toxic !!!) and then repeat the other treatment. If this does not work, try HASLing the circuits. If this does not work, then you may have real problems which will require you to strip the tin/lead. One can ask the question whether it may not be more economical to remake the circuits.

Brian

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