Has anyone else observed the following? We have a CMOS PQFP that was "popcorned" during reflow soldering. Cross sectioning clearly shows that the die, along with its mounting epoxy, has separated from the leadframe by approximately .002" (2-mils). There were no visible cracks in the plastic overmold material at 500X magnification. The problem is...some parts don't fail until after a few thermal cycles of 0 to 50 degrees C during live circuit testing at-speed. And...we can make them recover after failing by merely baking the entire board from 1.5 to 24 hours at 125 degrees C. The baking fix is not permanent and the parts eventually fail again. Some parts don't work initially but do work after the above baking treatment (we discovered, quite by accident, that baking "fixes" the parts). My question is...is the popcorning likely to be the only problem with these parts? Has anyone else been able to anneal a part so that it will recover from popcorning? Doesn't sound likely to me! Gary P. --- Gary D. Peterson _/_/_/ _/ _/ _/ SANDIA NATIONAL LABORATORIES _/_/_/ _/ _/_/ _/ _/ P.O. Box 5800, M/S 0503 _/_/ _/_/_/ _/ _/ _/ _/ Albuquerque, NM 87185-0503 _/_/_/_/_/_/ _/ _/ _/_/ _/ Phone: (505)844-6980 _/ _/_/ _/ _/_/_/ _/ _/ _/_/_/_/ FAX: (505)844-2925 _/ _/_/ _/ 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. * ***************************************************************************