Terri,
                        Thermal compound doesn't hold up well at reflow
temperatures, and can contaminate anything in its path when it spreads.  The
few times I've worked with such heat slug devices, we just applied solder
paste to provide thermal conductivity between the device and the board area.

                Mike McMonagle

                                -----Original Message-----
                                From:   Houston, Terri
[mailto:[log in to unmask]]
                                Sent:   Monday, August 21, 2000 1:50 PM
                                To:     [log in to unmask]
                                Subject:        [TN] Thermal pads used with
heatsink-down QFPs

                                Hi folks,
                                  I'm looking for information from someone
with experience in using thermal
                                pads (sil-pads) with QFPs having a heatsink
located on the underside of the
                                component. I can't seem to find pads of the
right thickness to fill this
                                gap, so I'm assuming that the rest of the
world was dispensing thermal
                                compounds on the boards for these types of
packages.

                                Thanks,
                                Terri


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