I agree with Werner. I spoke with a gentleman a while back from Baker Inteq. He was doing some experimentation involving vacuolar porosity in solder joints. His whole theory was that for years, all the way back to introduction of SMT, everyone has been creating voids in the solder joints due to flux "pockets" in the paste having no effective direction to out-gas. Therefore, when viewed by Xray, small voids can be seen right at the junction of pad/lead. His intent was, I believe, to open our eyes to something that has occuring all along. His findings, at the point that we spoke, was that there was no reason to believe this could be detrimental to the life of the joint. I used our Agilent 5DX to look at some in-house boards since I could slice down to the micro level at pad/lead junction. I too saw small voids where paste once was pre reflow. I had no reason to believe this could decreas solder joint life. However, this was performed only on leaded components, not BGA's. I would have no reason to believe this to be any different with BGA's. Even though the lead and joint between leaded and BGA are different, the mechanical alloy/intermetallic structure are similar. Jason Gregory Production Supervisor LaBarge Inc. (918)459-2367 [log in to unmask] Werner Engelmaier <[log in to unmask]> on 11/11/2002 06:10:45 PM Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond to [log in to unmask] To: [log in to unmask] cc: (bcc: Jason Gregory/LABARGE) Subject: Re: [TN] Void in BGA Hi Yannick, I would not spend much time on BGA SJ voids, since there is no real evidence that they are in fact detrimental in normal produuct. Werner Engelmaier Engelmaier Associates, L.C. Electronic Packaging, Interconnection and Reliability Consulting 7 Jasmine Run Ormond Beach, FL 32174 USA Phone: 904-437-8747, Fax: 904-437-8737 E-mail: [log in to unmask], Website: www.engelmaier.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 -----------------------------------------------------