In a message dated 4/9/99 12:47:55 PM Pacific Daylight Time,
[log in to unmask] writes:

<< You would use "sticky flux".  The same viscous flux that is used in
 solder-paste.  Contact your Solder Paste Vendor.  My impression is they all
 sell the stuff now for BGA and flip-chip attach.  It is often applied to the
 BGA balls by dipping the BGA into a controlled thickness of flux that is
 squeegeed onto a surface plate or squeegeed directly onto the board with a
 stencil.  The BGA attach is done with no-clean for very fine pitch balls.  I
 don't work at an assembly shop but I believe I've described is actually
 being done. >>

Yep Gary...

      Fer not working in an assembly shop you hit the nail on the head.
Actually, it's just a paste flux. Kester and Alpha both make it as I imagine
other suppliers as well. I believe that for the PPT process they had their
own formula and had added "Tackifiers" to it to make it a little more tacky
than regular paste flux.

      You're also right about the BGA stuff too. If you've ever heard of
SolderQuik (Russ Winslow shows up on the TechNet a lot, he's from
SolderQuik), paste flux is what's used to re-ball BGA's with their preforms
(which are the neatest thing since sliced bread by the way)...and speaking of
bread, when solderquik had their booth set-up at SMI last year here in San
Jose, they used a convection "Bagel toaster" to re-ball BGA's to show how
simple it was. Snicker if you want to, but it worked like a charm!

-Steve Gregory-

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