Wolfgang;
take a look at the (rough) sketch I have attached - is this the problem you
are describing?  If so, the only thing I have ever done to eliminate or
reduce this is to add a microetch step following the acid cleaner in the
electrolytic copper preclean process.

If you don't have a tank available, you can always add .25%-.5% v/v of
hydrogen peroxide to the sulfuric dip; you are not dragging in enough
peroxide to harm the copper bath but you will clean the copper surface
much better.  You just need to watch the dwell time...

Hope it helps;
Fred J.

>>> "Erat, Wolfgang" <[log in to unmask]> 02/27/98
01:36pm >>>
We have a customer which is very sensitive to separation between
plated
copper and outerlayer foil copper (doublesided product). This condition
is especially visible at high pad rotation after thermal shock. What can
be  done to minimize / avoid this issue ?

Wolfgang Erat / Viasystems Canada

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