Greetings:

The theory of dry film organics is one source for this type of material
building up in the sump.  It appears as a sticky dark residue on the sides
of the sump.  Carbon filtration is recommended by one of the large dry film
suppliers when using cupric chloride to avoid this buildup.  Once it has
accumulated on the sump surfaces there is no easy way of getting rid of it.
Adequate rinsing and air blow off from the developer is recommended to avoid
drag-in into the etcher not only of antifoam residues but also water.

Cheers,
            Brian

                -----Original Message-----
                From:   Mike Bailey [mailto:[log in to unmask]]
                Sent:   Thursday, December 16, 1999 10:26 AM
                To:     [log in to unmask]
                Subject:        [TN] Cupric Chloride residue

                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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