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"

Terry,

What is the aspect ratio of these vias? How are they metalized? Conventional
electroless copper or direct plate?
What cathode current density in the copper electrodeposition is being
employed?

Thanks,
Mike Carano

        -----Original Message-----
        From:   Terry Exell [SMTP:[log in to unmask]]
        Sent:   Monday, June 12, 2000 7:04 AM
        To:     [log in to unmask]
        Subject:        [TN] Variation in plating thickness on blind vias

        I am experiencing open circuits in blind vias on FR4 boards and I am
interested if
        other PCB users have experienced similar problems.  It seems that
the plating
        thickness varies along the length of the blind via and the open
circuit occurs at
        the point of minimum plating thickness.  I am wondering if this is
an industry-wide
        problem or whether one supplier has process problems.

        Regards

        Terry Exell

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