i have seen some SnAgCu (SAC) solder joint embrittlement and solder joint failure on parts larger than .2 inches during reheating of SnAg solder on a Cu PCB. (This is not really SAC solder but SnAg soldering to Cu PCB). Larger parts exhibit "Hot Tearing" as described in these 1998 NIST reports: See NIST report about "Hot Tearing" at Project Title: SOLDERABILITY MEASUREMENTS FOR MICROELECTRONICS at http://www.metallurgy.nist.gov/techactv1998/AnnualReport1998.html#electronics These non-eutectic alloys have a mushy freezing range, and TCE differences can rip the IMC apart fracturing the solder joints. See this analysis of Fillet Lifting by NIST. http://www.seas.ucla.edu/ethinfilm/Pb-freeWorkshop/pdf/handwerker.pdf Has anyone seen "Hot Tearing" with SnAg on OSP Copper PCB's ? Paul Signorelli Reliability Engineer Sanmina-SCI Corporation, Plant 432 702 Bandley Dr. Fountain, CO 80817 eMail address: [log in to unmask] Phone: 719-382-2352, Fax: 719-382-2520 --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------