Linda, Our data shows that using conformal coating as underfill can improve low and high cycle fatigue life of BGA solder joints. Years ago we conducted a test to compare the reliability of non-underfilled BGAs, BGAs underfilled with a conformal coating material and BGAs underfilled with reworkable epoxy. In general, BGAs underfilled with conformal coating lasted longer than non-underfilled parts but failed sooner than epoxy underfilled BGAs. It depends on what type of BGAs are being underfilled and what conformal coating material is being used as well as the test conditions. I cannot share more without legal papers. If you wish to know more, contact me offline. Tom --------------------------------------------------------------------------------- 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 e-mail to [log in to unmask]: SET Technet NOMAIL 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------