Dave, I am very interested in your comments, as we are looking into BGA underfill on our next design. I am looking forward to seeing your test data and any other comments you may have. Thanks, Jim Kittel L-3 Communications Salt Lake City -----Original Message----- From: Dave Hillman [mailto:[log in to unmask]] Sent: Thursday, February 06, 2003 6:35 AM To: [log in to unmask] Subject: Re: [TN] Speaking of Underfilling... Hi Steve! We have been using underfill materials for about 2 years very successfully on some of our designs. Our underfill procedures/guidelines mimic the underfill material supplier application recommendations - we didn't need to create any new or special procedures. We utilize underfill on both BGA and CSP depending on the use environment the assembly has to live in, although the thermal cycle reliability is more of a driver than vibrational reliability for many of our assemblies. We just finished up a very large DOE investigation which compared the thermal cycle life of ceramic and plastic BGAs in the underfilled and non-underfilled configuration. The thermal cycle recipe was -55 to +125C on a roughly one hour total cycle (we were following IPC-9701). The failure analysis is underway and I promised Peter/Technet I would pass on the results once we had the statistical analysis complete. It will be several weeks yet but when we finish up the microsections I'll pass on some of the findings. Dave Hillman Rockwell Collins [log in to unmask] Steve Gregory <[log in to unmask] To: [log in to unmask] m> cc: Sent by: TechNet Subject: [TN] Speaking of Underfilling... <[log in to unmask]> 02/05/2003 08:01 PM Please respond to "TechNet E-Mail Forum."; Please respond to SteveZeva Hi All! Peters thread about reworking a single ball on a BGA with underfill, brings-up a question. Are there any guidelines, or anything that someone would like to share, when to use an underfill? Is it something that is determined after ESS or HAST, and upon seeing failures then, which requires it? Or is there some sort of established guidelines that one can reference that say; "If you have BGA's on a assembly that will see "X" loads, then underfilling is necessary..." Question to the point; BGA's and Micro-BGA's on a missile...underfill these guys? -Steve Gregory- --------------------------------------------------- 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 -----------------------------------------------------