Ken, FYI - I worked on one production program with densely populated boards populated with multiple BGAs, which were conformally coated with parylene C and do not remember any BGA failures attributable to the parylene coating. Parylene coating thickness is relatively thin at .39 to 2 mils per IPC-A-610. Removal of a parylene coated BGA is another matter, however. "This e-mail and any attachments are solely for the use of the addressee and may contain L-3 proprietary information that may also be defined as U.S. Government export controlled technical data. If you are an unintended recipient of this e-mail, use, disclosure or distribution of its content is prohibited. Please notify the sender by return e-mail and immediately delete this message." From: TechNet [mailto:[log in to unmask]] On Behalf Of Ken Harp Sent: Wednesday, July 14, 2010 10:08 AM To: [log in to unmask] Subject: Re: [TN] Underfill as a Remedy for Electro Migration? I have a tangential question for Doug regarding the BGA thermal cycling performed with conformal coating as underfill...it looks like the BGAs in question were completely underfilled with conformal coating (from the board up to the underside of the BGA package). Is this correct? Any experience(s) with the effects on solder joint fatigue/reliability when using thin film vapor condensate parylene coating in leiu of acrylic or Loctite products for BGA underfill? --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 ----------------------------------------------------- -----Original Message----- ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 -----------------------------------------------------