The following message was posted by anon,
Has anybody experienced any major problems with replacing electroless 
plate with a direct plate system ? Currently we are evaluating the carbon 
and graphite systems

We at Artetch replaced our Electroless some 2 years ago, initially with 
the Atotech Neopact Palladium based system in a vertical process mode 
using the existing Electroless plating plant. Neopact is an excellent 
product and allowed the reduction of hazardous chemistry whilst giving a 
reduction of 1 hour in our process cycle against electroless copper. We 
also had the safe guard of understanding palladium chemistry and the 
knowledge we could switch back to electroless within a few hours if 
necessary.

Having tasted some of the benefits of direct plate we then wanted to move 
to horizontal processing to gain more benefits and finally opted to go 
with a carbon system, the main factors after the process were the 
equipment cost and footprint.

I agree with Paul Gould you must evaluate all the options with care, in 
our evaluations we found that to avoid wedge voids caused by erosion of 
oxide at the inner junction you must use a reduced oxide despite all of 
the restrictions this will impose on your processing, this was true for 
every system we evaluated. If you do not process multilayer then no 
problem

Our experience with both systems has been good, initially we had problems 
striking thru the hole at pattern plate this was caused by a delay in 
ramp up of the copper plate rectifiers removing the delay solved the 
problem of 'dog boning' or strike thru, the incidence of voids is no 
worse than with electroless copper, you must be prepared to run as good a 
control system as you did with copper but you will find maintenance is 
significantly reduced, be warned you cannot skimp the maintenance and 
expect to achieve consistently good results I believe many have tried and 
then blamed the process as being unreliable.

We process upto 14 layers on FR4, upto 8 layers on Polyimide with aspect 
ratio's of upto 8:1 and Blind via's using blind drilling and sequential 
building, our carbon system ( Macdermid Blackhole single pass ) copes 
with this. We also process using reverse current pulse plating rectifiers 
at pattern plate, direct plate works ok with this technology as well.

Good luck in your evaluations.

Clive Bell
Artetch Circuits Limited
Littlehampton. UK

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