seen the pictures, and rad the responses. A lot of good posts. At the risk
of being redundant, her's what I've run cross as root causes for this sort
of dewetting.

1. LPI Solder Mask residue. Either from incomplete developing, poor rinsing
and dried in place, or redeposit from a poorly ventilated cure oven. Either
case difficult to see with naked eye prior to HASL processing.

2. Oxidation of copper from LPI cure bake not properly removed by preclean
for HASL (microetch).

3. Poor flux wetting to surface. Boards not properly dried of rinse waters
after pre-clean and prior to application of flux at HASL. Trying to flux wet
panels doesn't work well. Or poor flow of flux through the flux rollers.

Hope this helps

Bob Dube

ES&D
-----Original Message-----
From: Stephen R. Gregory <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Wednesday, September 06, 2000 2:33 PM
Subject: [TN] HASL Dewetting...


>Hi All!!
>
>Got some boards in at receiving that are exhibiting dewetting on the pads.
>You can see what I mean at:
>
>http://www.driveway.com/share?sid=e25a88c4.8e904&name=Pictures
>
>I'm rejecting them of course, but what would be the most likely cause of
>something like that? I'm pretty sure it's some form of contamination, but
>what?
>
>Thanks!
>
>-Steve Gregory-
>
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