I disagree - with this type of component, the intent is not to create a homogeneous mix - the intent is to solder to the ball, and some amount of diffusion will occur in the process. Retaining the Sn90Pb10 ball gives the joint added height, which increases the reliability of the package. The determining factors are those for a typical solder joint - ensure that the joint meets the appropriate reflow profile for the solder paste being used. Ben -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Vladimir Igoshev Sent: Friday, February 27, 2009 11:07 AM To: [log in to unmask] Subject: Re: [TN] Reflowing CBGA component (with high Sn balls) using Eutectic solder paste Hi Joe, You have to make sure there is enough time above the liquids temperature, as you'd want to get a homogenous mix of Sn and Pb in the final joints. -- Best regards, Vladimir mailto:[log in to unmask] SENTEC 11 Canadian Road, Unit 7. Scarborough, ON M1R 5G1 Tel: (416) 899-1882 Fax: (905) 882-8812 www.sentec.ca --------------------------------------------------- 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 -----------------------------------------------------