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Date: | Thu, 26 Jun 97 09:48:41 |
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Jim,
For true conductor protection, all exposed surfaces must be
coated. If conductive liquids bridge the gap between balls
of different potentials you've got trouble.
So, this would seem to dictate vertical dipping as the only reliable
means of coating. But, the coating must not be allowed to remain
in the space between the board and the device, after dipping,
due to high relative thermal expansion mismatch of solder
and cured acrylic.
The opinions expressed herein are not necessarily those of my
employer.
Lyn R. Lynch
Coates ASI
______________________________ Reply Separator _________________________________
Subject: ASSY: CONFORMAL COATING BGAs
Author: [log in to unmask] at internet
Date: 6/26/97 9:18 AM
Does anyone have any experience applying conformal coating on an assembly which
contains BGA components? Is it necessary to ensure that all solder joints are
coated? If so, how it it done and how is it verified?
My specifics are: Military contract
625 ceramic BGA
.030" stand-off
Acrylic coating
Any opinions will be welcome.
Thanks,
Jim Marsico
(516) 595-5879
[log in to unmask]
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