Hello, can anybody help me please?  We are getting low level (up to 5
microns high) copper spots left on inner layer panels after the cupric
chloride etch.  It happens on most kinds of laminate.  We have put panels
through our chemical clean line and the etch only and the effect is still
there.  Leaving out the chemical clean line or pumicing the panels first
still leaves the spots.  The surface is shiny copper and sometimes there
appears to be some residue which we believe to be organic from a slight
carbon peak on an EDAX scan.  We found some sticky residue on the rollers
in the etcher which we removed, but the problem didn't go away.  We run at
4N HCl and 520mV, regenerating with hydrogen peroxide.
Has anyone experienced this before?  Did you discover where the organic
residue came from and the best way to remove it?

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