Anne:

Actually you can get rid of the ammoniacial etchant stains, but it is slow and tedious.  We have had to do this here on occasion.  Just make up a bath of isopropyl alcohol and ammonium hydroxide.  This solution will redissolve the etch salts.  You can soak the panel or use a soaked cloth or Q-tip.  Like I said this can be very tedious. As with an acid dip be leary of damaging the treatment.

Joe Aronson
Wet Process Engineer
JMSPI

>>> Yu-Shan Han <[log in to unmask]> 08/17/99 11:00PM >>>
Anne:

If the etch stain is like white-blue (caused by ammoniacal etchant), you
can't get rid of it.  Run the core back through stripper might help.  Acid
dip hurts the treated surface so the core will be scrap anyway.

Yu-Shan Han
Lead One Technology, Inc.
Seattle, WA
(206) 368 - 8429

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Joe Aronson
Sent: Tuesday, August 17, 1999 6:34 AM
To: [log in to unmask] 
Subject: Re: [TN] Innerlayer issue


Anne,

This is definately not typical with other manufacturers.  The resin content
of the material may be too low and/or the depth of the glass bundles is too
shallow.  Check out other suppliers.  This may eventually lead to delam
which is a much nastier demon than the staining.  If acid dip (10%sulfuric)
does not get rid of the staining you may want to try an aggressive acid
cleaner (something associated with a final finish preclean).  From a
material quality standpoint this condition should be deemed unnacceptable.
Hope this helps.

Joe Aronson
Wet Process Engineer
JMSPI

>>> Anne Ledger <[log in to unmask]> 08/17/99 07:45AM >>>
Good Morning Technetters,

I have a question for board fabbers.  Problem:  We are experiencing
weave texture on our innerlayer material.  I have spoken to the
manufacturer who states that weave does shift in the "pour" of the
material (when the resin is added) and that there is no specification
that controls the depth requirement of the weave.  The topography is
visual prior to lam/image.  The condition is causing our resist to lift
slightly and allows an etch stain on the double treat foil that so far
we can not remove.  Question:  Is this a typical condition of innerlayer
material (other manufacturers)?  Is it double treat foil only?  Is there
a way to remove this type of etch stain?  What is the acceptablity of
stain on inner layer foil?  I can't find any reference info in IPC.

Any and all input would be appreciated.

Anne Ledger
EMDS, Inc.

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