Hi Joe! Well, as Joyce observed, Parylene will coat everything, so that's one (expensive) way. Another way is to underfill the BGA before coating, with an underfill material. This is what we are currently doing. I do question the ability of anyone to truly meet that requirement though, when using a conventional spray technique. For example, if you have vias under components (which is pretty much standard these days) then you will have exposed circuitry unless you are using a dry film solder mask. regards, Graham Collins Process Engineer, Northrop Grumman Canada Corporation Halifax (902) 873-2000 ext 6215 >>> [log in to unmask] 08/08/03 03:04PM >>> Tech Netters, I am looking for some input on a special issue related to the conformal coating of boards with BGAs. According to IPC-A-610C, section 9.1.2, voids in the conformal coating material can not expose circuitry, bridge lands or adjacent conductors. In order words, all exposed circuitry/conductors are to be conformally coated. BGAs have conductors/solder balls located "under" the package unlike leaded parts where the leads are exposed and easily covered with conformal coating material. Conformal coating may partially wick under the BGA covering some of the conductors/balls but not all the way. Some of the BGAs also stand off the board a measurable distance which the conformal coat material may not bridge resulting in an uncoated gap between the BGA and the pwb. Some would interpret this as leaving exposed conductors (under the BGA). I would like to know how other manufacturers are dealing with this issue. Ideally, one would seal the perimeter of the BGA with conformal coat thereby not exposing conductors but conformal coat material will not bridge gaps greater than x mils. Look forward to your response. thanks joe --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------