Seems like tenting the via will fill that, but I'm not sure it is "guaranteed" to fill it all the time, nor wick down into the hole--but for such a small hole I don't think it would have to flow across it.  I use 0.015" vias as a rule, and the majority of time they are sealed--but once in a while boards from a vendor (not sure which) won't, must be a really thin soldermask or they must be doing a pullback or something. 

Shawn Upton
Section Head, Test Engineering
Sensors Business Unit
Allegro MicroSystems, LLC
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603.626.2429/fax: 603.641.5336

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steven Kelly
Sent: Thursday, April 23, 2015 10:13 AM
To: [log in to unmask]
Subject: [TN] Via Fill

Hi All,
Do you think it is feasible to do non-conductive via fill on a .0025- .003 finished hole size - overall thickness is .028. Regards Steve

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