Kiko,

You can call Enthone for information on a process to
100% plug vias if you are interested.
We had a customer that requested this because of a fear
they had of having flux entrapped in the via and causing
shorting.
We had numerous problems with outgassing during plug
cure and also during reflow once the boards had reached our
customer--some even causing exposed copper as the plug
blew out of the via.
We have been experimenting with Enthone and it seems to
work--though we have only used it on one part line so far.

Dave Rist


>>> Adeodato Vigano <[log in to unmask]>
12/08/98 11:09am >>>
I have received an RFQ for boards that need to have vias
plugged with liquid mask AFTER hot air leveling.  I can't think
of a good reason why someone would want to plug vias at
that stage (as opposed to the more conventional plug before
LPI coating) and whether this process would be effective
during successive reflows of the board during assembly, but
maybe I'm missing something.
Any help would be greatly appreciated.
Kiko Vigano
---------------------------------------------------------
Adeodato Vigano
Compunetics, Inc. - PCB Division
phone (412) 858-6115
email [log in to unmask]
---------------------------------------------------------

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