This is a valid technique with microvias, which are necessarily blind and of small
diameter. They are left open and cause no subsequent soldering problems because the
volume of solder 'robbed' in filling the hole is so small that there remains largely
sufficient for the real solder joint. Frankly, I know of no reliable way of doing this
with drilled through-vias. FWIW

Brian

Bob Dube wrote:

> We are a PWB fab house.
>
> We' ve recently come across a requirement to fab boards with vias located in
> SMT pads. The requirement is to have these vias completely shut and as close
> as possible to flush with the pad surface. Initial thought was given to
> copper plating completely shut but have CTE concerns. Thought is also being
> given to epoxy fills and then metallization.
>
> Does anyone have any thoughts on the best way to achieve this condition? Are
> there any reliability pitfalls?
>
> Thanks in Advance,
>
> Bob Dube
> ES&D
>
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