Hi Ed, I have do agree with you that none of the responses you have received explain your solder joint failures. I did not respond, because I have never seen anything like this. The only thing that comes to mind is that there are some trace impurities in the copper and/or solder that migrated towards the interface between the copper and the IMC layer. So the only advice I can give you is to run an elemental analysis on both fracture surfaces and see if there is anything there that should not be. I would appreciate hearing about the outcome of this. Werner Engelmaier Engelmaier Associates, L.C. Electronic Packaging, Interconnection and Reliability Consulting 7 Jasmine Run Ormond Beach, FL 32174 USA Phone: 904-437-8747, Fax: 904-437-8737 E-mail: [log in to unmask], Website: www.engelmaier.com ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################