We recently installed a new DES line using cupric chloride with sodium
chlorate regeneration.  We have been experiencing a blue/black residue that
coats the etch filters and seems to find it's way into the spray nozzles
etc. etc.  We beat the fluoride theory and seal degradation to death and
have found nothing substantial.  I have been told that others have
experienced this problem and have attributed it to various causes such as
developer drag-in, anti-foam contamination and leaching of dryfilm organics.
I've also heard of others that have retrofitted carbon filtering systems on
to their etchant recirculation pumps. I should note that this is brand new
"high end" equipment with plenty of water rinse stations and blow-off
modules.  Does anyone have any experiences they would care to share? Thanks
in advance.

Mike Bailey
Director of Engineering
McCurdy Circuits Inc.
4900 E. Hunter Ave.
Anaheim, CA  92870
Phone: 714 507-4900 Ext 253
FAX: 714 507-4911
e-mail: [log in to unmask] <mailto:[log in to unmask]>

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