Have you considered using a PWB that has been solder bumped and flattened
using the solid Solder Deposit (SSD) approach developed by Siemens? This process
is available from two outfits in the US, one on each coast. SSD has been
tested for coplanarity mismatch, can compensate for 4-6 mils mismatch. Sure sounds
a lot simpler than making your printing process more difficult.
(Contact me directly if you would like email addresses for the two SSD
suppliers; getting a few test boards run may solve your problem.)

Bill Kenyon
Global Centre Consulting
P.O. Box 553, Montchanin, DE 19710 USA
Tel: 302.652.4272     Fax: 302.652.5701   Cell: 302.377.4272
email: [log in to unmask]

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