You can, but with a higher DPMO. Nitrogen reduces the ability to form oxides that prevent wetting just prior and during reflow. Without it, and especially at higher temperatures with alloys that are more resistant to wetting than 63/37, the difference becomes greater, especially on BGAs. The price of the nitrogen option is usually not a great amount. I would recommend buying it with the capability to do so. You may need every weapon you can find in your arsenal to promote wetting to the outer edges of the pads, and being able to get solder to fully flow over the terminations using the Pb-free alloys. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Neil Maloney Sent: Wednesday, January 18, 2006 2:32 PM To: [log in to unmask] Subject: [TN] Time to fish or cut bait Greetings, Technet! My company is making the transition from leaded to lead -free assembly in the US (we have already converted our overseas facility) Now we are in the throes of the N2 vs. air battle. Our overseas unit uses air only without any problems (ENIG boards, 0602s to QFPs, no BGAs) In the US we are looking to start designing BGA and flip-chip assemblies with the same type ENIG and Entek boards. We are buying a new 10 zone reflow oven, and battle begins. Do we start with nitrogen or not? Can a small company make lead-free BGA assemblies without going to an N2 atmosphere? Does air make the process window too small for BGA? Our smallest PCB is about 8x12cm. Thanks in advance Neil Maloney, Manufacturing Engineer Contemporary Control Systems, inc 2431 Curtiss St Downers Grove, IL 60515 (630) 963-7070 x132 [log in to unmask] http://www.ccontrols.com <http://www.ccontrols.com/> http://www.ctrlink.com <http://www.ctrlink.com/> --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 1.8e 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 -----------------------------------------------------