MIchael,
Not sure what your black stuff is, but usually they are non-conductive :-)
You might try one of Hysol (Loctite's) glob top encapsulants for COB
applications.
From your meager detail, it is a bit hard to suggest a specific product, but
scrounge around their web site and have a look
<http://www.loctite.com/electronics/>
If you try the FP 4470, you will likely need a dam material. Others require
no dams
Steven Creswick - Gentex Corporation
        -----Original Message-----
        From: Mike Kuczynski [mailto:[log in to unmask]]
        Sent: Monday, December 09, 2002 9:40 AM
        To: [log in to unmask]
        Subject: [TN] Mounting Modified BGA


        I need some information in mounting a BGA asic, that has been
modified. The top is cut-off, modifications to the wirebonds to the die are
made. Then it's sealed w/ this black gunk and covered
        by this yellowish film. The problem is that this black gunk is
melting and shorting out the whole die, when the BGA is being mounted on the
PCB.

        Is there a different sealant (black gunk) we should be using to
close up this BGA? Could it be exceeding the temp. when mounting the BGA? Is
there another process we should look at?


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