Ted, Is the package warping slightly and the corners turning downward? Is the solder mask damaged at the corners due to the cleaning process? Also, sometimes I have noticed that BGA replacement using a hot air rework station results in a lower package stand off distance if solder paste is not used (and possibly due to the slight downward hot air pressure pushing the package down). joe -----Original Message----- From: Ted Kong [mailto:[log in to unmask]] Sent: Monday, August 11, 2003 2:54 PM To: [log in to unmask] Subject: [TN] BGA bridging on corner pins only Hi All at Technet Land, Can someone explan why do I see bridgings only on the corner pins during rework? The package is a 1517 Pin BGA and the rework was done on the SRT rework station with only flux (No paste). When I run the same board and component through the reflow oven, I see no bridging. I tried lower the air flow and increase the spacing between the board and the chimney, but neither helped. Any input is greatly appreciated. Thanks all in advance. Ted Kong __________________________________ Do you Yahoo!? Yahoo! SiteBuilder - Free, easy-to-use web site design software http://sitebuilder.yahoo.com --------------------------------------------------- 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 -----------------------------------------------------