What about partially filled PTH (with leads) and PTV. Any evidence that
this reduced reliability?

> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier
> Sent: Tuesday, October 01, 2002 12:28 PM
> To: [log in to unmask]
> Subject: Re: [TN] PCB design with mask over vias.
>
>
> 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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