Dear Ann,

Mark hit on some excellent points for your situation. In terms of spray
impingement, experience has shown that high impingement fan nozzles in the
stripper chamber benefit in removing residues. Minimize your hold times
between lamination and development. If the staining is caused by the dye in
the resist, ask the resist supplier what active ingredients in a resist
stripper will help with this situation.

Best regards,

Mike Carano

        -----Original Message-----
        From:   Mark Mazzoli [SMTP:[log in to unmask]]
        Sent:   Tuesday, April 18, 2000 9:59 AM
        To:     [log in to unmask]
        Subject:        Re: [TN] Imaging Issues

        At 09:38 AM 4/18/00 -0400, you wrote:
        >Good Morning All,
        >
        >Today, I am tasked with gathering some research info on primary
imaging
        >of double treat multilayer material.
        >
        >We have experienced some staining and lock on situations in the
past and
        >I am looking for any input from board fabricators with any similar
        >history.
        >I understand that some of the newer treatments (Zbz?) have a
similar
        >appearance.  Appreciate all info, from TechNet or direct.
        >
        >Anne Ledger
        >Process Engineer
        >EMDS, Inc.
        >[log in to unmask]

        Hi Anne,

                 I spent quite a bit of time finding the best chemistry and
overall
        procedure for processing doubletreat laminates.  Areas I had to come
to
        terms with were:

                 * Fingerprints - overall handling
                 * Resist lamination parameters
                 * Resist choice
                 * Developing - particularly rinse characteristics
                 * Stripping - the most challenging process in a successful
        doubletreat program

                 I found no shortcuts.  Just basic process engineering.
Such as
        looking very closely at the resist laminator to make sure the exit
        temperature is ALWAYS at optimum for doubletreat.  Training
personnel in
        handling procedures.  Making sure I had adequate rinsing in the
developer
        and that the pH of the waters were reasonably close to neutral.

                 The biggest issue I faced was the stripper.  Both from a
machinery
        and a chemical standpoint.  This often overlooked manufacturing
process
        will bite you hard when processing doubletreat.  Finding the right
        chemistry to match your machinery is important.  I don't know if
you're
        using filterable or dissolvable chemistry so I can't make any real
        suggestions regarding your process.  But I can say that you'll need
to do
        plenty of testing in order to find the right blend for your
equipment and
        doubletreat.  And clearly, your machine's ability to provide
adequate
        impingement AND water spray is very important.  Look very closely at
your
        machinery.  A lot of shops neglect this system.  Doubletreat won't
tolerate
        the neglect.

                 You may want to ask your laminate supplier to give you
names and
        numbers of other manufacturers using their doubletreat.  Call these
guys
        and talk to them about the problems you've seen.  They've seen the
same
        thing and will be much more able to give you names of dry films and
resist
        strippers over the phone than on this forum.

                 Doubletreat is a good product when you learn how to use it.
It's
        worth the effort.

        Good luck,

        Mark Mazzoli

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