We are currently fabricating 8- to 14-layer boards for one of our
     customers; most of the internal layers of these boards are 2 oz.
     (.0028" nominal thickness) copper foil.  This amount of total copper
     thickness within the board cross-section causes throughput and yield
     challenges at drilling.

     Our request to remove nonfunctional pads has raised the traditional
     concern of plated through hole reliability with versus without
     nonfunctional pads.

     1) Can anyone point me to documented reliability test results
        (temperature cycling) that support the removal of nonfunctional
        pads in multilayer PWBs?

     2) Since I haven't obtained my copy of IPC-2222 yet, will someone tell
        me if the wording from IPC-D-275 (Paragraph 5.3.2.5 Nonfunctional
        Lands) has been changed in IPC-2222?

     Regards, Dave Wolf
     HADCO Corporation
     612/893-1466
     [log in to unmask]

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