A good wish list! But you may need to vary attribute parameters of the
material to meet the varying needs of your electronic configurations. An
encapsulant for a thick small application may not work for a thin large
configuration. Increasing the filler loading, type of chemistry (e.g.,
biphenyl vs multifunctional, etc), sophistication level of your supplier and
volumes you buy will decide most of the parameters you have listed. Some of
the parameters like voids may very well be a function of your process.
Syed.

        -----Original Message-----
        From:   Edward Boucher [SMTP:[log in to unmask]]
        Sent:   Wednesday, August 12, 1998 2:49 PM
        To:     [log in to unmask]
        Subject:        [TN] The ideal eletronic encapsulation material?

        Greetings Technet,

         Dose anyone know of a encapsulating material for electronics, which
can
        meet  the majority of these parameters?  We have been searching for
about a
        year and have had little success.

        The Ideal Encapsulation Material

        a.  low toxicity
        b.  low moisture permeability
        c.  no or very low ionic content
        d.  low viscosity
        e.  low linear shrinkage
        f.  low glass transition temperature (Tg)
        g.  low Coefficient Of Expansion (CTE)
        h.  low embedment stress
        i.  high tensile strength
        j.  high thermal conductivity
        k.  void free
        l.  electrical insulation properties
        m.  thermal cycling stability
        n.  high thermal shock resistance
        o.  wide temperature range -55 to 95 degrees C
        p.  good chemical and solvent resistance
        q.  good adhesion
        r.  low cost
        s.  ease of processing (application and clean up)
        t.  no formation of water
        u.  non-corrosive
        v.  easily repairable


        Your help is appreciated...

        Ed Boucher
        Engineering R&D Tech.
        K and M Electronics
        413-263-6253

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