Hi Gaby, I'd prefer to see SEM images, as optical are not as informative in this particular case. However, those "dark lines" do not look like cracks. The joints appear to have some Pb "concentrated" closer to the PCB interface implying that it could have been a mixed process. If you don't have access to an SEM you can send them to me. Regards, Vladimir SENTEC ------Original Message------ From: Gabriela Sender: TechNet To: [log in to unmask] ReplyTo: TechNet E-Mail Forum ReplyTo: Gabriela Sent: Jul 4, 2009 03:54 Subject: [TN] Weird solder joints Dear all, By cross sectioning BGA solder joints on a failed assembly, I found that the suspected joints are not uniform and that they contain unusual separation areas. I suspect mixed assembly and/or bad reflow profile. Steve was so kind and enabled me to send the links. Please may I have your opinion? http://stevezeva.homestead.com/files/small.jpg <http://stevezeva.homestead.com/files/small1.jpg> http://stevezeva.homestead.com/files/small1.jpg <http://stevezeva.homestead.com/files/small2.jpg> http://stevezeva.homestead.com/files/small2.jpg http://stevezeva.homestead.com/files/small3.jpg <http://stevezeva.homestead.com/files/small4.jpg> http://stevezeva.homestead.com/files/small4.jpg Gaby --------------------------------------------------- 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 ----------------------------------------------------- SENTEC 11 Canadian Road, Unit 7. Scarborough, ON M1R 5G1 Tel: (416) 899-1882 Fax: (905) 882-8812 www.sentec.ca