Inge, I found this very interesting. Thanks. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge Sent: Tuesday, November 11, 2008 10:47 AM To: [log in to unmask] Subject: Re: [TN] Effect of Soldering in a Ni atmosphere on BGA reliabilty My contribution is not an exact answer on your question, but may be of interest for some people. There are many ways to minimize the amount of flux and control the atmosphere in which the soldering take parts. One way that we have introduced recently is to use 'vacuum' VP. Sounds strange, and it is. This machine pumps out the air in the soldering chamber during the top temperature stage. So, the solder will wet better into voids and surface, while at the same time the oxygen level is decreased. It's not a real vacuum of course, but enough lowered air pressure to have a clear positive impact on the solder joint quality and also result in less flux residues. If you are interested, you can read about it below. http://www.ibl-loettechnik.de/downloads/Aktuelles/Todays%20Vapor%20Phase %20Soldering%20SMTAI%20Orlando%20-%20080820.pdf Inge ----- Original Message ----- From: "Eric CHRISTISON" <[log in to unmask]> To: <[log in to unmask]> Sent: Monday, November 10, 2008 1:47 AM Subject: [TN] Effect of Soldering in a Ni atmosphere on BGA reliabilty >A customer has experienced solder joint failures in a lead free BGA device >which are unexpected for us. > > The test the solder joints failed was a shock test in the plane of the PWB > and the joints failed at the interface between the SJ and our BGA device > substrate. > > We've done similar tests without failure but when we did our trials we > soldered the devices onto the boards in a hot air oven. Our customer used > a nitrogen oven. Could this affect SJ strength in any way? > > Just wondering whether this is worth investigating. > > Regards, > > > -- > Eric Christison Msc > Mechanical Engineer > Consumer & Micro group > Imaging Division > > STMicroelectronics (R&D) Ltd > 33 Pinkhill > Edinburgh EH12 7BF > United Kingdom > > Tel: +44 (0)131 336 6165 > Fax: + 44 (0)131 336 6001 > > --------------------------------------------------- > 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 > ----------------------------------------------------- > --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------