Hi Rex, Can you X-section one of the BGAs? It would be a good start and tell a lot. If you don't have the capabilities, I can help you. Regards, Vladimir SENTEC SENTEC 11 Canadian Road, Unit 7. Scarborough, ON M1R 5G1 Tel: (416) 899-1882 Fax: (905) 882-8812 www.sentec.ca -----Original Message----- From: Rex Waygood <[log in to unmask]> Date: Wed, 4 Nov 2009 16:35:52 To: <[log in to unmask]> Subject: [TN] BGA Balls We have built a batch of pcbs for a customer who supplied the pcbs. They are 2mm thick 6 layer with 0.2mm vias and ENIG finish. None work fully, they work intermittently at best. The customer was suspicious that we had not reflowed the BGAs correctly. Our under BGA temp on a similar pcb is 245C (We now have some samples to profile correctly) The customer is suspicious due to the comment on page 753 http://www.atmel.com/dyn/resources/prod_documents/doc6221.pdf <http://www.atmel.com/dyn/resources/prod_documents/doc6221.pdf> where it states a min of 250C Close x-ray evaluation of the BGAs showed tear dropping along tracks, uniform balls, everything looked tickety boo. We offered to remove a BGA to see what was happening underneath. 2 corners showed a similar issue with the ball where it separated from the BGA rather than the pcb. The removal technique was to use a PDR IR rework station, under board heating to bring topside pcb temp to 170C and then a lead free reflow profile to bring the device up to reflow, manual removal. I didn't have dye for dye and pry so thought this might show if there was an ENIG problem. I was surprised by the almost complete removal of ball at the device and lack of evidence of solder. Was this just caused by my investigation processes? Was the ball device interface broken which prevented it from melting the ball? Any other clues? Thanks Rex Hopefully Steve has received the images (sorry about the size!) Rex Waygood Technical Manager Hansatech EMS provides value manufacturing through engineering and quality ________________________________ Hansatech EMS Limited Benson Road Nuffield Industrial Estate Poole Dorset BH17 0RY United Kingdom Tel: Fax: DDI: +44 (0)1202 338200 +44 (0)1202 338202 +44 (0)1202 338222 [log in to unmask] www.HansatechEMS.com <http://www.hansatechems.com/> --------------------------------------------------- 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 -----------------------------------------------------