======== Original Message ========
        We have been laminating with single ply construction at our Buffalo
facility for three months now and have not experienced any problems. We
have recently started to laminate with single ply at our Maple Grove
facility and have run into a problem. I was wondering if anyone has come
across this same problem. What we are seeing is copper spots in the oxide
after lamination. We etched the foil off of several panels and to one
degree or another we have seen these spots. We ran several test lots with
the single ply 7628 high resin layup and our standard 1080/2116. The copper
spots did not show with the 1080/2116 layup. We are using Electrochemicals
oxide and we go into a post dip(reducer). Our laminate supplier seems to be
leaning toward the oxide as the problem. If anyone has experienced this
problem let me know.

Anthony Carfagna
Engineering Manager
Universal Circuits, Inc. - Buffalo

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======== Fwd by: Richard MacCu ========
Mr. Carfagna,

Please describe the location of the spots.  Are they on the outer surface of
the panel?  When you etch the foil off are the spots visible as remaining
copper or on the innlerlayer now visible throught the prepreg layer?

If they are on the outside of the panel and remain as spots when the foil is
etched,  then prepreg dust is getting on the surface prior to lamination.
You can rerun the test and use your desmear/etchback to remove it before
etching.
If the spots are visible on the innerlayers through the prepreg layer,  then
run some oxide and bake the panels as though they were being laminated.  If
by chance the prepreg was contaminated and affecting the oxide this will
show it.  If the spots appear due to baking, preclean or rinsing in oxide
may be at fault.

Good Luck,
Richard MacCutcheon

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