Hi All Further my Question "IS the Oval shape pads on PCB for BGA soldering help for better analysis in x-ray inspection". We are using that type of pads in our prod. and when we see the round image of any ball we assume that this ball is not soldered properly and the solder flow is less so we do rework for the same. Is that the correct method? your opinion Pls. Thanks With regards Pankaj Karnwal QualityAssurance BESL A-4,Sec-5 NOIDA,201301,INDIA e mail : <mailto:[log in to unmask]> Barco,innovators in image processing > ----Original Message----- > From: Werner Engelmaier [SMTP:[log in to unmask]] > Sent: Monday, January 27, 2003 6:07 AM > Subject: Re: BGA micro cracks > > Hi David, > When you get intermittents, that means you have a full crack not a > micro-crack. Fractured solder joints are notorious for this, and cannot be > found by X-ray or visual innspection. Your description makes me suspect > not > so much solder joint cracking, but interfacial separation due to 'black > pad' > or a similar problem causing an absence of a metallurgical bond. > Cross-section some of these joints to see what you have, an effective > screening procedure is vibration. > > 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 -----------------------------------------------------