The problem can be resolved by reducing the belt speed dramatically, if using N2
atmosphere. The flux may not be breaking down the coating before becoming 
liquidous. The flux may also need to be changed as there are some pastes that 
are not compatible with Entek!

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______________________________ Reply Separator _________________________________
Subject: BGA defects
Author:  [log in to unmask] at ftl03
Date:    10/2/96 7:12 PM


We are experiencing a problem with SMT assembly of CBGA modules onto Entek 
boards.  On about 1% of the boards (a significant number at our volumes), 
solder from one or more of the pads does not wet the pad during reflow but 
wicks up onto the ball, creating an open.  The defects appear to be randomly 
located and are only noticeable when we use no-clean solder paste.  Previous 
studies have indicated that our oven profile is not the problem.

Does anyone have experience with this kind of problem?  Any ideas would be 
greatly appreciated.


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