In a message dated 06/10/99 9:28:41, [log in to unmask] writes:
> Can anyone tell me what the minimum tin/lead plating thickness should
> be inside a plated through hole?

Hi David,
You did not say whether you are talking about PTHs or PTVs (vias).
For PTVs, there is no need for any tin/lead plating.
For PTHs, into which you want to solder component leads, the tin/lead plating
thickness will provide some protection to preserve the solderability of the
underlying copper, but you need to consider that tin/lead plating is porous,
and thus not very good at this job. Thus, tin/lead plating typically is
reflowed. To get good solderability shelf life you need about 5 micro-meters
of solder; on the other hand, there is no critical need for having good
solderability inside a PTH barrel. Thus, there is no industry standard on this

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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