Have you try baking the parts for 24 hours at 125 C? Do you know the history of your BGAs? Rudolph Yu Manufacturing Engineer -----Original Message----- From: Henry Rekers [mailto:[log in to unmask]] Sent: Thursday, May 16, 2002 1:34 PM To: [log in to unmask] Subject: [TN] BGA warpage - defects in the corners. This is a tough one. We have had intermittent problems with a particular bga (Motorola 357 ball, 50mil pitch) The defect manifests itself as a "head in pillow" joint near the corners of the part always on the outside rows. It's a real nasty one because most of the time it is not detected electrically until aged and/or shaken. Sometimes you can physically push on the part and make the connection. We've had some Shawdow Moire testing done and the part deflects 6.5mil and the corners throughout the reflow temperatures (independant of soak time) The reflow profile is bang on. I don't suspect the print or paste. Have you ever delt with a problem like this? How did you fix it? Thanks in advance. Henry J. Rekers Manufacturing Engineer. ---------------------------------------------------------------------------- ----- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL 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 1.8d 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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL 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 ---------------------------------------------------------------------------------