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Super cleaning rolled copper foil, How?

 

I am developing a new product. Process Development Engineer. It will be used in the electronics market and requires ultra-clean, hard as-rolled copper foil. The product uses rolls of thin foil(1/2 and one oz/ ft2) as raw material and output is in sheet form. As the foil is manufactured in a rolling mill it is typically "dirty" by clean room standards-- ours. We already use tacky rolls to pre-clean it and that is not enough. We are concerned with particles as small as 4 and even less than 10 microns. Bigger ones are totally fatal.

What is the best way, process, chemicals, systems, etc. to pre-clean this foil before I introduce it to my super clean processing? I am considering electro-cleaning and wet spray systems. Should I be looking somewhere totally different?

Brian Schreiber
3M - Maplewood, Minnesota, USA

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The molds for compact discs are electroformed, as are complex print heads, stampers for vinyl records, fresnel lenses, etc. 4 microns is not small, it's big (in some applications).See letter 2941 for a photo of an item where the plated path plus the gaps total 4 microns. Conventional wet processing plating lines are often installed in Class 100 clean rooms. So you are looking in exactly the right direction with electrocleaning and spray systems.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey