Hi Steve,
In order to preserve solderability fot longer shelf lives, the solder layer
after HASL is best at 5 micro-meters and above. Less solder will have
increasingly shorter solderablility shelf lives depending on storage
conditions.

Werner Engelmaier
Engelmaier Associates, Inc.
Electronic Packaging, Interconnection and Reliability Consulting
23 Gunther Street
Mendham, NJ  07945  USA
Phone & Fax: 973-543-2747
E-mail: [log in to unmask]

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