Conductive via fill is more for thermal dissipation that just providing
a flat landing site for via in pad.  Epoxy fills are much lower cost and
will provide a fairly planar surface for mounting.  A disadvantage is
that epoxy does shrink during cure - considerably more than the
copper/silver loaded materials - and in absence of a specification you
should state the requirement for flatness that you need at the via
location.  



Jeffrey Bush
Director, Quality Assurance and Technical Support

                          76 Technology Drive - POB 1890
                             Brattleboro, Vermont 05302-1890
                                Tel. 802.257.4571.21 Fax. 802.257.0011
                                    [log in to unmask]
                              http://www.vtcircuits.com	



-----Original Message-----
From: Michael Bonek [mailto:[log in to unmask]] 
Sent: Monday, July 26, 2004 11:59 AM
To: [log in to unmask]
Subject: [TN] conductive via fill drill drawing note


We want to fill our via's in smd land with conductive material so the
land will be flat and no PPT will fall into the hole. I cannot find an
IPC specification that calls out a conductive via fill for a drill
drawing note. I know not to be too specific on the type of material to
be used and that I do want it planerized and followed with subsequent
plating finish. Is anybody aware of an IPC drill drawing specification
or would like to share how they specify this process on there drill
drawing?

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Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
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