Hi Bob! I have used tin/lead HASL (yea, I know its not Pbfree but I wanted a baseline), immersion tin, immersion silver, and ENIG pwb surface finishes in a variety of Pbfree soldering process investigations. All of the finishes performed adequately. Keep in mind that Pbfree soldering processes are going to be running a minimum of 34C hotter than typical thus anticipate that you will experience increased surface finish thermal exposure degradation (loss of solderability, discoloration, etc.). Inert atmospheres (e.g. nitrogen) can help open up the process window but are not absolutely necessary. My personal preference is immersion silver. Good Luck. Dave Hillman Rockwell Collins [log in to unmask] Robert Walker <[log in to unmask] COM> To Sent by: TechNet [log in to unmask] <[log in to unmask]> cc Subject 01/18/2006 11:39 [TN] RoHS board finish AM Please respond to TechNet E-Mail Forum <[log in to unmask]> ; Please respond to [log in to unmask] OM Hi All, I'm doing my first PCB design that will use lead-free components and I need to change my board finish from what I've always used.....HASL. I'm looking for any recommendations or comments on the best board finish to use. The components used on the design will be a mixture of tin-lead and lead-free (SAC), so I'm not sure if there is a preferred finish to use in this type of situation. I work in a prototype environment where the boards may be reworked (BGA removal/replaced) a number of times, so I'm concerned about the ability of the finish being able to handle being reworked/reflowed a number of times. I'd also welcome any recommendations on the type of board material to use since it will see an elevated temperature of up to 260C. I've always just specified FR4 in the past. Thanx in advance for any feedback. Regards, Bob Walker [log in to unmask] (mailto:[log in to unmask]) --------------------------------------------------- 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 -----------------------------------------------------