If the via in pad is plugged with soldermask from the farside and this
is bleeding on the pad this can be an issue.  VIP should be plugged
prior to final plate to hide the via in the pad.  Soldermask plugs
should be used when the mask is covering both sides of the pad.  

Jeffrey Bush
Director, Quality Assurance and Technical Support
VERMONT CIRCUITS INCORPORATED 
           76 Technology Drive - POB 1890 
              Brattleboro, Vermont 05302
                Voice - 802.257.4571 ext 37 
                    Fax - 802.257.0011
                       <http://www.vtcircuits.com/> 
                           

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Wee Mei
Sent: Wednesday, January 18, 2006 10:46 PM
To: [log in to unmask]
Subject: [TN] Plugged via issue

Hello,

Recently I took over the inspection of bare boards and noticed that the
vias
are plugged with solder mask and some has small drop overflow on the pad
surface. Some of the SMD packages have via-on-pads with 0.3mm diameter
via.
I cam concerned about solder reliability. The via diameter is 0.3mm and
during fabrication, they are pluged with solder mask.

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