Hi Joe - could you please check your solder alloy element ratio, did you really mean Pb90Sn10? The Sn90Pb10 begins melting at 183C and the Pb90Sn10 begins melting at 268C. I am not familiar with CBGA using a Sn90Pb10 ratio. Dave Hillman Rockwell Collins [log in to unmask] Joe Macko <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 02/27/2009 10:03 AM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to [log in to unmask] To [log in to unmask] cc Subject [TN] Reflowing CBGA component (with high Sn balls) using Eutectic solder paste Hi All, My question is related to the soldering of IBM PPC CBGAs type components (that have Sn90Pb10 solder balls) using Sn63 paste onto ENIG finished boards. What are the "determining-factors" to improve the wetting/diffusion of the eutectic solder paste into the high Sn solder balls. The eutectic solder appears to wet well to the ENIG pads located on the board but occasionally I see eutectic solder fillets that do not always appear to fuse well with the high Sn content balls (if fuse is the correct word?). thx Best Regards, -Joe "This e-mail and any attachments are solely for the use of the addressee and may contain L-3 proprietary information that may also be defined as U.S. Government export controlled technical data. If you are an unintended recipient of this e-mail, use, disclosure or distribution of its content is prohibited. Please notify the sender by return e-mail and immediately delete this message." --------------------------------------------------- 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 -----------------------------------------------------