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Thu, 8 Apr 1999 15:37:03 -0600 |
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Bill,
If you have multilayer thru-holes with devices inserted on the assy, then the benefits of prebaking are much greater than a strictly surface mount board. Polyimide's inherently higher Tg is a good arguement against it, but from what I've seen, the reliability of the innerlayer connection is higher when prebaking prior to high temperature excursions.
Richard MacCutcheon
BFGoodrich
>>> "Mengers, William D." <[log in to unmask]> 04/08 2:02 PM >>>
Guys (and girls),
Can anyone tell me whether or not polyimide boards need to be pre-baked
before processing thru nitrogen reflow for solder melt? We are doing it,
which of course means added expense. Is it really necessary? We bake at
110 C for four hours. Is there evidence which suggests that it is
necessary.
Thanks for any replies,
Bill Mengers
Northrop Grumman Corp.
Baltimore, Md.
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