Hi Rick,
I have seen no evidence, nor do physics-of-failure considerations suggest
there should be any, that there is an "increase in PTV barrel strength by
filling the hole with solder." PTV interconnect structures can suffer 2 major
failure modes: (1) barrel fracture, and (2) inner-layer separation [ILS].
Barrel fracture: I have seen no evidence, nor do physics-of-failure
considerations suggest there should be any, that there is an "increase in PTV
barrel strength by filling the hole with solder" regarding this failure mode.
ILS: Filling the PTV barrel does strengthen the PTV barrel radially--it thus
can resist the compressive loads from the resin thermal expansion trying to
collapse the barrel.  There is both experimental evidence and analytical
reasons; however, I have not seen an analysis yet quantifying this effect.

Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL  32174  USA
Phone: 904-437-8747, Fax: 904-437-8737
E-mail: [log in to unmask], Website: www.engelmaier.com

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