Mike,

Is your replenishment chemistry coming in on top of or below the surface of
the etchant? It should come in near the bottom of the sump due to the fact
that you are adding chemistry that is lighter than the etchant itself and
does not mix well above the surface. We have seen people incorrectly connect
our Vis-U-Etch controllers that way and the chlorine gas produced does not
blend and react with the etchant. After running the return pipe down to the
bottom, the black sludge problem dissappears. I believe it is a chlorine gas
reaction with the dry film that creates the sludge.

If you have any more questions or would like to contact me off-line, send an
e-mail to: [log in to unmask]

Hope this helps.

Best regards,

Phil Culpovich
Oxford V.U.E., Inc.
626-256-6557

In a message dated 12/16/1999 7:07:06 AM Pacific Standard Time,
[log in to unmask] writes:

> Subj:       [TN] Cupric Chloride residue
>  Date:    12/16/1999 7:07:06 AM Pacific Standard Time
>  From:    [log in to unmask] (Mike Bailey)
>  Sender:  [log in to unmask] (TechNet)
>  Reply-to:    <A HREF="mailto:[log in to unmask]">[log in to unmask]</A> (TechNet
E-Mail Forum.), [log in to unmask] (
> Mike Bailey)
>  To:  [log in to unmask]
>
>  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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