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Double Zincate/Cyanide Copper 2:1 aspect ratio

I have an application to plate electroless copper in holes with about a 2:1 aspect ratio. This is a specialized printed wiring board where the PWB is bonded to an aluminum (6061)substrate. We drill the hole (.056") into approximately .100 overall thickness circuit board + aluminum.

The process we are specifying is:
Double Zincate followed by cyanide copper. We will then take the board an complete it in a PWB shop. (Electroless copper, acid copper etc.)

Two questions. Is the zincate/copper process proper for this application? Will a standard cyanide bath throw into the 2:1 aspect ratio holes or do I need to modify the bath?

Thanks

Peter Menuez
Electronics Mfr. - Mason, Ohio
2004

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2004

Peter.

I will say now. To get a good adhesion on aluminium with copper you must have a higher copper content and a low cyanide content. You can try this recipe:

copper cyanide 57g/l. sodium cyanide 56 g/l. sodiumtartrate 60 g/l. sodiumcarbonate 30 g/l Ph-range 10-10,5. Temperature 40-55 °C. Current 2-3 A/dm2.
 

Regards

Anders Sundman
4th Generation Surface Engineering
Consultant - Arvika,
Sweden