Tony:

        One of the most overlooked aspects of the "Roughening"  process is
the operational temperatures of the swell and the
         etch. In order of importance temperature is by far the most with
concentration and time following up.

        In some materials you will find that there is a sharp cutoff when
the Swell and Etch are below 168 C .Thus steps should be
         undertaken to assure a uniform temperature of the solution from the
top to the bottom. ( stratification can easily occur in
         large open tanks. )  Uniform solution mixing is very important to
the operation and repeatability of the roughening.

        Secondly the need for high temperatures in the Glycol based systems
is greater than the NMP based versions.

        Additionally a bake prior to "Roughing " will improve the rate and
severity of attack by the process chemistries.

        Lastly the surface of a drilled hole can vary dramatically in
process characteristics. The drilling operation itself can glaze the
         hole wall, or apply localized heat, or even increase the surface
roughness.

        Contact me and we can discuss some findings I have on this subject
if it will help.

        Russell L Smith
        Ciba Specialty Chemicals
        [log in to unmask]


From: Ed Cosper
To: [log in to unmask]
Subject: Re: [TN] Permanganate Problems
Date: Thursday, July 22, 1999 9:08AM

Joe,

What type of Permanganate are you using. Potassium or sodium.  This may make
a big difference. Once works well on higher Tg materials while the other
should basically be used for standard 130 Tg FR4.  I believe the sodium is
better for the high Tg materials.

Ed Cosper
 -----Original Message-----
From: Joe Aronson <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Wednesday, July 21, 1999 5:34 PM
Subject: Re: [TN] Permanganate Problems


Tony,

I know someone who regularly works with permanganate and polyclad.  Ted
Myers at JMSPI.  Hope this helps.


Joe Aronson
Process Eng
JMSPI

>>> Tony Charais <[log in to unmask]> 07/21/99 08:09AM >>>
  We are seeing an occasional problem with our current permanganate process.
We have a DOE running but we are having problems developing topography in
the hole on a given product. This is a high aspect ratio multilayer board.
We are confident that the problem isn't related to fluid transfer in the
hole. This product is based on a PolyClad core. Has anyone else had problems
with PolyClad material? We are wondering if it could be something to do with
their resin. Any support from the technet would be appreciated.

Tony Charais
Manufacturing Engineer
[log in to unmask]

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