>From your description of the failures I can not form a very accurate picture. If I understand you correctly, your problem may be more related to thermal expansion differences. This subject is complex enough, that I give one- and two day workshops on the issue of thermal expansion mismatches and solder joint reliability. Werner Engelmaier Engelmaier Associates, Inc. Electronic Packaging, Interconnection and Reliability Consulting 23 Gunther Street Mendham, NJ 07945 USA Phone & Fax: 201-543-2747 E-Mail: [log in to unmask] *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************