We have had similar issues in out cupric etcher.  To combat these we took the
following actions and it has cleared up.
1. Installed carbon packed filters on the cupric recirculation lines
2. Corrected a problem with serious over adding of defoamer in the developers
prior to cupric etch
3. Cleaned and replaced most of the rinse nozzles after develop.

We found defoamer and resist residues in the rinse after develop enough that
the rollers were sticky and it was carrying into the etcher.  As all three
changes were made we could see a drop in the TOC (an measure of the organic
levels) in the cupric solution.  This test although it worked significantly
degrated the test equipment during our period of testing.

Good Luck.

Respectfully, Rick Haynes

------------------
Original text

From: Ted Stern <[log in to unmask]>, on 1/12/98 4:32 PM:
Hello All:

I need help trying to minimize "organic" contamination occuring in a
cupric chloride final etch.  The contamination is a "black", gummy
material which floats on the surface of the bath in clumps.  If the line
is not cleaned periodically, black spots on the surface of copper
(typically not the laminate), can be seen in inspection.

The DES line processes only innerlayers utilizing CibaGiegy (0.9 mil
nominal thickness) and Dyanchem FL 1.3 mil photopolymers as etch
resists. An FTIR scan has been performed on the residue, both
photopolymers, and the "rollers". While not entirely conclusive, the
scans more closely resembled the photopolymers and not the rollers.
Visually, the rollers do not seem to be swelling or deteriorating.

The etching bath is operated at 1.3 N HCl, regenerated via chlorine gas
(ORP control), and sees both 1 oz and 2 oz copper.  I am unsure of the
laminate being employed.  Continuous carbon filtration has been employed
with some degree of success.  The carbon filters are changed weekly:
one 30" filter per 450 gallons of bath.

Can anyone offer suggestions to better control or eliminate this
residue?!  Thanks in advance

Ted Stern

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