Has there been any studies completed to prove or disprove thermal coefficient problems between ceramic BGA's mounted on FR4 causing long term reliability problems of the BGA balls (solder ball separating from PWB) over commercial and industrial temperature ranges? Commercial temp range: 0O C to +70 O C. Industrial temp range: -40 O C to + 80 O C. --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------