It is extremely unlikely that your oxide process is causing the problem.  If
the copper does not take oxide, then there is something on the surface that
inhibits oxide coverage; something that can't be cleaned off in the alkaline
cleaner or microetch.

The most likely culprit is resin spots.  The resin is getting on the copper
during lamination; either through pinholes in the copper or resin dust in the
environment.

When you etch the foil off a laminated panel, are there spots of copper that
remain unetched?  If so, resin spots are the cause.

Mark Dowding
Regional Technical Service Manager
INSULECTRO

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