Hi Ed, Your real problem is the testing requirement. While, for automotive applications cycling of -40C to +140C with 30 minute dwell times makes sense, the10 sec transition most likely does not (where in an automobile to you get a temperature ramp of 18C/sec—even reflow soldering ramps are limited to 2C/sec). It is this T-shock condition of 1080 C/minute that is killing your assemblies. You are setting up hugh transient warpages in both components and substrate putting the solder joints in tension. When I was still at Bell Labs, we once soldered two ceramic components together (to assure that there was absolutely no CTE-mismatch) and T-shocked them. Our results were similar to yours; both solder joints as well as metallizations failed. Your problem is neither solder related nor process related; it comes from your sales people accepting a job with a real crazy requirement. On the other hand, I really would not want a car with some electronics that could withstand only 1000 cycles. From a design point-of-view, your only possible solution is to put leads onthese components that are very compliant in the z-direction. Not a very practical solution, not to speak of the cost. 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] ################################################################ TechNet E-Mail Forum 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://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################