We use via in SMD pad and are successful. We soldermask over the bottom side via without clearing the hole. Mask material enters the via usually plugging it but if not it drastically limits the amount of solder scavenging. Prior to assembly we bake the bare boards to remove any moisture left in the uncured soldermask (UV light usually cannot get into the vias to completely cure the mask). The boards are assembled using normal process and so far we have not experienced any problems.

Richard

-----Original Message-----
From: Bill Robinson [mailto:[log in to unmask]]
Sent: Monday, January 17, 2000 6:14 AM
To: [log in to unmask]
Subject: [TN] VIAS IN PAD


We have pruchased a PWB design for use in one of our products.  This design
has through vias in the surface mount pads.  Has anyone had experience with
this situation?  My first concern is losing solder through the via during
reflow.  Is there a good way to fill the via and still have a good solder
joint?  And what other kinds of problems can we expect?  thanks for the help.

Bill Robinson

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