This looks like a case of over-plating, (nodules on pads) where the
current density is either too high for the board in question, or they
are isolated via pads, which will incur a high CD. Remedies for this are
low CD and/or thieving. Other possibility is that they have been in the
plating tanks too long, but if the CD was correct, then all that should
happen is that the plating just gets thicker and stays smooth.
Subsequent etching will show an overhang, which could trap dry film
resist.

Colin McVean
Production Manager
Artetch Circuits Limited
Tel: 01903 725365

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Al Onderick
Sent: 03 May 2005 16:40
To: [log in to unmask]
Subject: [TN] Via contamination

Greetings Tech netters,



            In the past we've had problems with tented vias not
completely
tenting and trapping liquid.  The liquid would boil and find its way to
the surface of the board.



While this looks similar these vias were not tented.





http://www.texas-gold.org/PCB/



Al Onderick

National Instruments


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