Hi Bob,
The call out of finished hole size is an anachronism left over from the
through-hole technology era. In modern high-density PCBs you should specify the
drilled hole size (no tolerance) with a minimum plating thickness in the hole to
be verified by cross-sectiong of coupons.
The reliability of your vias depends on PCB thickness, drilled hole size, Cu
plating thickness, Cu plating quality (verified by testing co-plated mandrel
foils for tensile strength and ductiolity--not elongation). Your friend is
right,
electrical test is not enough. You should have coupons either IST or
HATS-tested. This will be even more important with LF-soldering temperatures. You then
might want to specify not only Tg, but Td and CTE(z) as well.

Regards,
Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL 32174 USA
Phone: 386-437-8747, Fax: 386-437-8737, Cell: 386-316-5904
E-mail: [log in to unmask], Website: www.engelmaier.com


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