MIke,
I ran into similar situation many moons ago. Where the chemicals ate
the cotton, I couldn't bring myself to wear polyester. You described
the Filters for the etch section, but what nozzles are clogging in which
section? Are we talking etch section still.
1. Anyhow, although I defined explicit procedures, I found that
operators still allowed the breakpoint to carry beyond the maximum
40% breakpoint within that chamber. A longer Develop
dwell is better.
2. This based on a KCO3 bath, just for reference.
3. I did not have regeneration, but I did have a feed and bleed
system with a pH meter monitoring the sump. When the pH fell
below 10.3 (?), the operators were required to feed the day tank at
about 1 gallon/min (if I remember correctly) using a flow meter. I
always had problems with
operators not mixing the KCO3 in 5 gallon drums properly, but
instead in the 100 gallon day
tank. The pH was never right the KCO3 would fall out
all the time.
4. I had operators putting the wrong resist lam rolls on the
incorrect panel sizes. It was 50/50 if they cut the residual resist
hanging from the panels prior to and following image. This residual
would then find its way into the sump and the post rinse due to its
size.
5. Its possible the filters for the etchant section are not being
properly cleaned, in terms of
which are removed first or second. You should have 2~3 filters
prior to the pump, the last
having the highest screen mesh.
6. I had nozzles clogging all the time due to operator error, in
terms of running and maintenance.
7. The same would happen in strip, but not as critical, other than
removing residual film.
If I can shed anymore boring light, call me.
John Gulley
Director of Technology and Marketing
Texatronics Inc.
972-367-2709
-----Original Message-----
From: Mike Bailey [mailto:[log in to unmask]]
Sent: Thursday, December 16, 1999 9:26 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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