Hi Jim! Sounds like you have the problem of excessive ball collapse with BGA's solved! I wonder why the OEM's haven't done something like this? It's not like this is an obscure problem... Silly question; is it possible to replace only the corner balls with Hi-temp balls? See? I told you it was a silly question... -Steve Gregory- It just so happens that we build a multi-chip module using a 625-BGA package. We buy the empty package from Kyocera, install multiple die and discretes, seal the lid, attach the balls (4 hi-temp in the corners) and solder the BGA to our PWB. Jim Marsico Senior Engineer Production Engineering EDO Electronics Systems Group [log in to unmask] <mailto:[log in to unmask]> 631-595-5879 -----Original Message----- From: Steve Gregory [SMTP:[log in to unmask]] Sent: Wednesday, September 24, 2003 3:25 PM To: [log in to unmask] Subject: Re: [TN] 5Sn / 95Pb Solder Sphere Jim, Do you get the devices like that, or do you put the hi-temp balls in the corners yourself? Thanks! -Steve Gregory- Victor, we use high temp solder balls on the 4 corners of a 625 ceramic BGA. The main purpose is to prevent the device from collapsing, causing solder bridging. Maintaining the stand-off height after reflow also increases long term reliability. Jim Marsico Senior Engineer Production Engineering EDO Electronics Systems Group [log in to unmask] <mailto:[log in to unmask]> 631-595-5879 --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------