Jim Mc Neal asked when "tented" vias are required with LPI soldremask.

Here (Aerojet) our application is space / vacume environment.
_When_ we require a soldermask (smt parts bonded to pwb _with_ 
vias under the part) we will tent the via.  on all other applications
our designs are pads-only (so we don't need _any_ soldermask)
We tent so that we don't entrap air (or contaminants) in the pwb.

HTH,

Bill Gaines
AeroJet (for $) 1100 Hollyvale, Azusa, Calif. 91702-0298
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