On Dec 27 T. Gaylor ask about research on sputtering copper into plated
through holes. About 7 years ago we were trying to plate depth drilled blind
vias. (.008" drill size, .010" deep). We try all types of vibration and
"thumpers" on our electroless copper bath and could not get satisfactory
results. We finally tried sputtering the copper in the holes. This worked
very well and passed up to 400+ thermal cycles. Unfortunately, this was
expensive (about $75 for an 12x18" panel). We had them done by Action
Technologies in Colorado. Jay Schumacher was President of Action at the
time. Also I believe Fasel Faslin of APS in Florida had a vertical
conveyorized sputtering machine about the same time. It has been a while and
I'm not as young as I used to be, but I think the above names and numbers
are correct.

An aside: While we were doing these experiments, I heard that someone in
Japan (maybe Fujitsu or Hitachi) was working with electroless copper in a
vacuum chamber. Does anyone currently do this successfully?

David Arivett
Cuplex Inc. 

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