Another issue arises concerning "exotic" materials as Thermount with a very high water absorption percentage and OSP's. Imaging using this material with its associated pre lamination prepreg and core bake and its baking requirement before assembly, especially in a very uncontrolled high humidity situation, while using OSP's. Also, think about using Thermount with plastic BGA's. It's CTE/TCE (changed for me in 1972 Werner just like ft./lbs to lbs/ft.) is lower than ceramic in the x/y axis. Negative CTE/TCE I believe it is called. MoonMan --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------