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Hi Werner,
What about some consideration for the HAL or solder prep. ? It
is known to "etch" away some of the copper.. thus reducing eventually the
thickness of the barrel at its weakest places ?
Very Best Regards - Roland
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-------Message original-------
Date : mardi, 01.
octobre 2002 23:06:46
Sujet : Re: [TN] PCB
design with mask over vias. 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 --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 --------------------------------------------------------------------------------- . |
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