John, Why not consider BT, which is what most BGAs are made from? It comes in a variety of thicknesses and prepregs, has a very high Tg & Td, and is very flat and smooth. Happy Holden Asian Pacific Materials John Burke <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 01/20/2006 06:25 PM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to John Burke <[log in to unmask]> To [log in to unmask] cc Subject [TN] Laminate material I am using a standard 0.62 thick laminate 6 layers. The board size is 1.375 by 2 inches. It is a lead free assembly and is a little unusual in that it has BGA and QFP components on the top, but is mounted with 300+ bga balls on the reverse side, so in effect is actually a component when finished. I am making this out of Polyclad 370HR, and have no coplanarity issues with the finished product. I have a request though to make the product thinner for one customer application. Anyone have suggestions on a material that could be mechanically stable enough to reduce the current board thickness in order to achieve this - as I said it needs BGA flatness and is assembled at 260 C twice by us (components and ball attach) and once by the customer. Thanks in advance, John --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------