This info is passed on from a co-worker of mine.

There may be an organic "funk" growing in the etching sump chambers. This
can and will deposit on the rollers but also breaks off and can be deposited
onto the board surfaces during processing. Thus cleaning rollers is
important but not the complete cure.

If it is organic crud, what can be done is pump out the etcher and examine
the walls of the sump, at the solution line will be a slimy dark/black goop.
Use equipment cleaner or 15% caustic solution to leach the sumps and run the
etcher to have the entire machine 'dosed' (the solution will turn dark or
black as the stuff is removed.) If you plan on re-using the etchant you must
filter it back into the sump or the problem will bloom once more.




>From: "Scott B. Westheimer" <[log in to unmask]>
>Reply-To: "TechNet E-Mail Forum." <[log in to unmask]>,              "Scott B.
>Westheimer" <[log in to unmask]>
>To: [log in to unmask]
>Subject: Re: [TN] Low level shiny copper spots after cupric chloride
>etching
>Date: Tue, 27 Jan 2004 14:58:38 -0500
>
>Catherine,
>
>I am not sure what you mean when you say it happens on most kinds of
>laminates? It is possible that there is epoxy residues on the panels which
>occurs during the manufacturing of the laminate if the lay up area is not a
>clean room. However if you mean when you say that this is happening on most
>kinds of laminates and you are referring to different laminate
>manufacturers
>than I would say that it is a in-house problem and some where in your
>pre-clean or etching operation you are introducing a surface contaminate.
>May be something on the rollers.
>
>Hope this helps
>
>Scott Westheimer
>
>----- Original Message -----
>From: "Catherine Smith" <[log in to unmask]>
>To: <[log in to unmask]>
>Sent: Tuesday, January 27, 2004 1:15 PM
>Subject: [TN] Low level shiny copper spots after cupric chloride etching
>
>
> > Hello, can anybody help me please?  We are getting low level (up to 5
> > microns high) copper spots left on inner layer panels after the cupric
> > chloride etch.  It happens on most kinds of laminate.  We have put
>panels
> > through our chemical clean line and the etch only and the effect is
>still
> > there.  Leaving out the chemical clean line or pumicing the panels first
> > still leaves the spots.  The surface is shiny copper and sometimes there
> > appears to be some residue which we believe to be organic from a slight
> > carbon peak on an EDAX scan.  We found some sticky residue on the
>rollers
> > in the etcher which we removed, but the problem didn't go away.  We run
>at
> > 4N HCl and 520mV, regenerating with hydrogen peroxide.
> > Has anyone experienced this before?  Did you discover where the organic
> > residue came from and the best way to remove it?
> >
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