Hi Jeffrey and all,
Things are not quite as simple as has been portraied--the density of ED
copper is not a fixed number, it varies depending on the plating details of a given
batch.
This is the reasopn ED Cu foil is given as a weight per area, not as a fixed
thickness. The situation is further muddies, because many of these foils have
a variety of adhesion "tooth" geometries.
Thus, to say "copper weights in oz - 1/4, 3/8, 1/2, 1.0, 2.0, 3.0, 4.0 are as
follows in microns - 9, 12, 18, 35, 71, 107, 142" is not correct. The micron
numbers are only the metric equivalents of the mil numbers, BUT the
mil-thicknesses are only NOMINAL values with significant +/- ranges.

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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