It is possible to solder SAC balls using Pb:Sn solder. BUT... It is important that the profile be adjusted so the SAC balls fully melt and there is enough time for the two types of solder to mix well, preventing the stratification of solders often noted when this is tried. I know of no way to check for this full mixing except through cross sectioning polishing and either looking for PB islands in all parts of the solder ball, and verifying by EDX that Pb is found throughout the solder ball. You need to be able to view the Pb islands in order to exclude the possibility of Pb smearing over the surface when polishing. mark Mark Woolley -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Croslin, Robert Sent: Tuesday, October 21, 2008 10:10 AM To: [log in to unmask] Subject: Re: [TN] Lead Free BGA'S We had one of our long time CM's do exactly this on a project last year with disastrous results. They did it without our knowledge trying to meet an impossible schedule. Some of the devices passed test and began failing immediately while others never passed. They had to rebuild the entire lot on their nickel. The only positive thing was when one of our other proposed doing the same thing recently and we were able to say H**L NO! Like Deac replied "It's either lead free or it AIN'T!!!!!!!!!" Bob Croslin The Nielsen Company -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of John Foster Sent: Tuesday, October 21, 2008 11:21 AM To: [log in to unmask] Subject: [TN] Lead Free BGA'S Our assembly house recently assembled some boards with Lead Free BGA's for us and when I asked them if they used a lead free process they responded with. We use leaded solder (Sn63Pb37) with a hybrid oven profile to accommodate the lead-free BGA. I hope this answers your question. Please let me know if you have any more questions." Is this a common process, is this a reliable process Any input is appreciated Thank You John Foster --------------------------------------------------- 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 -----------------------------------------------------