I see your point Eric. The size of the balls is actually a manufacturing error, the balls were intended to be 0.35mm in diameter, so the pad size was designed at 0.25mm on both the component and the PCB. So, since nobody comments on the size of the traces and the pad size from the mechanical and stress and CTE point of view, I guess the design is OK... Thanks to everybody that answered, Ioan -----Message d'origine----- De : TechNet [mailto:[log in to unmask]] De la part de Eric CHRISTISON Envoyé : July 21, 2008 4:14 AM À : [log in to unmask] Objet : Re: [TN] Mechanical damage to BGA Measure the size of the pad on the underside of the BGA device. The size of the pad on the PWB should be about the same size to make the joint of equal strength at both interfaces. 0.25 for a 0.60mm dia ball sounds far too small to me. Agreed though that you may still get failure at depanelisation due to board flexure. Best to avoid that. Regards, Eric Christison Msc Mechanical Engineer Consumer & Micro group Imaging Division STMicroelectronics (R&D) Ltd 33 Pinkhill Edinburgh EH12 7BF United Kingdom Tel: +44 (0)131 336 6165 Fax: + 44 (0)131 336 6001 --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 847-615-7100 ext.2815 -----------------------------------------------------