Hi Ioan,
PTVs filled with solder mask/epoxy during the soldering processes will
experience less compressive loads on the copper barrel, and thus less tensile
stresses which are part of the loading leading to innerlayer separation. During
operationall use, this fill plys no significant reliability role.
PTVs filled with solder of course offer no advantage during the soldering
processes--they are filled during them. In operational use, fully filled PTVs are
subjected to reduced loads on the copper barrel than empty ones, and PTVs
with voids in the solder fill will experience localized higher loads due to the
stress concentrations---having said this, it needs to be emphasized that this
is only significant if the operational conditions are severe, such military and
automotive.

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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