Hi Gaby, Just a thought, are you 100% certain that the features which you have shown are not caused by scoring/scratching/handling on the surface of the section? Could be some contact on the delicate sample surface between final polish and observation, perhaps during etch or rinse steps, or even during mounting onto a slide for viewing (dirt of the sample press)? This could explain the continuation of a feature from the solder joint into surrounding mould resin or soldermask. Would be worth ruling out and again SEM inspection of the sample would clarify. Would also be happy to take a quick look at them in the SEM for you if you don't have access. Kind regards, Stewart Stewart McCracken MCS Ltd. t. +44(0)131 440 9090 f. +44(0)131 440 9085 e. [log in to unmask] w. www.themcsgroup.co.uk -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Gabriela Sent: 04 July 2009 08:01 To: Administrator 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------