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Electroplating baths for gold and copper

2004

Dear Sir/Madam,

I am research student. Currently , I am working on methods to electroplate copper and gold on the surface of a glass chip using potentiostats. I need to acquire a thickness of 20 microns on a patterned device with 8 microns width. But I am still in search of an appropriate recipe. I would be very grateful if anybody can help me with my problem as I am desperately trying to seek an answer. I look forward in hearing from you as soon as possible.

Thank you Regards,

Mr Clement Lo
Research Student - Birmingham, West Midlands, United Kingdom

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I would suggest you refer to textbooks on electroplating and then discuss your ideas with your supervisor. There are also a few electroplating supply houses around the Birmingham area, so they may be able to help you as well. You may find it a problem plating a thickness of only 8um to a thickness of 20um, so you will have to rethink your approach. Copper plating is relatively easy, as are many other metals, but when you are doing gold, you will probably be handling cyanide and this can kill people. Consequently, I strongly recommend you talk everything through with your supervisor before you start trying to handle cyanide.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2004

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Well,

Being in Birmingham, you should find a plating company on almost every street corner (perhaps not in the current economic climate !), not to mention the Jewellery quarter. You also have the headquarters of the Institute of Metal Finishing (Exeter house in Holloway Head) and the Headquarters of the Surface Engineering (SEA)Trade Association in Vyse street, as well as some of the big plating chemical supply houses such as Macdermid in palmer street. Birmingham reference library probably has as many books on electroplating as you would care to read. So there's plenty of scope in Birmingham for help and advice.

Best of luck and don't wear your shoes out !

Regards,

Richard Guise
- Lowestoft, U.K.
2004

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You could not be in a better place to seek advice. The headquarters of the Institute of Metal Finishing is a local phone call away. Don't be put off by the cyanide in gold plating solutions. It is heavily bound up in the double gold potassium cyanide complex and there is very little free CN. This is why such solutions commonly operate at c. pH 3 - 4. Ask IMF for a copy of my paper on 'Cyanides in Metal Finishing, Risks and Alternatives' - published in 'Transactions'. You are also welcome to attend any local IMF meetings and talk with some very experienced platers.

Good luck with the project. I suggest you throw away the potentiostat and use a small lab power supply with constant current. Plating scales down very well but you are dealing with very small areas.

Geoff Smith
Hampshire, England
2004