Hello all,

Well, as you can see I am catching up on emails today.  One or two comments
on this mailing.  I have been Laser MicroViaing (new term?) fail-safe
reliable PWBs for well over 5 years.  And yes it was tough to get approvals
relative to "Plated Through Holes" it came down to a lot of testing.  At my
previous employee we made two rules: no BGAs and no MicroVias.  The day after
that we had no choice and we were in the BGA with microvia product deliver
service.  Hence, yes MicroVias; like BGAs are in the military product and
will be in future.
On the through hole via and solder mask: the best tented via is the one that
isn't.  Encroachment of solder mask onto pad is best (leaving the via empty).
 If the need to "tent" is required (I hate that word tent) than I like the
epoxy via fill and then subsequent mask.  It is more expensive but product
appropriate.
This is relative to Military and Space Product, Commercial Applications do
have more choices.  Product Appropriate Design is Everything.

Boston Brad
781 858 0783