We took a simple approach and sealed the periphery of BGAs with a bead of
silicone adhesive after the conformal coating process.  This worked well.

Jim Marsico
Senior Engineer
Production Engineering
EDO Electronics Systems Group
[log in to unmask] <mailto:[log in to unmask]>
631-595-5879


        -----Original Message-----
        From:   Gray, Matthew D HS-SNS [SMTP:[log in to unmask]]
        Sent:   Thursday, May 22, 2003 9:54 AM
        To:     [log in to unmask]
        Subject:        [TN] Conformal Coating Application Method for BGA

        Hello -

        I am requesting feedback to material and processes that have
provided
        environmental performance protection for BGAs and other large array
        packages.  The performance environment of consideration is corrosion
and
        humidity.

        Can users provide particular details regarding application process
spray
        (inclusion of steps used for flood/fill/etc), dip, other, and
material that
        has provided a high amount of coverage and ability to protect
electrical
        connections and components in humidity and salt fog environments.
Ideally,
        these materials are below the parylene step.  All feedback is
appreciated.

        Regards - Matt

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