I believe immersion tin DOES promote whiskers, although not at the same level as electrolytic tin. Check IPC-4554, especially Appendix 6. "A potentially significant source for whisker formation are stresses induced from formation of CuSn IMCs....Whiskers have grown on immersion tin conductive features. To date, these whiskers have appeared at ambient conditions..." As for using cc for mitigation, it has also been found that whiskers will still grow under (and even penetrate) coating. Check NASA paper "Effects of Conformal Coat on Tin Whisker Growth". Regards, Kevin -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Dehoyos, Ramon Sent: Friday, March 24, 2006 11:34 AM To: [log in to unmask] Subject: Re: [TN] Tin Whisker Mitigation Dewey: I hear you loud and clear. In the near future thanks to some crazy fellows that want to save the earth.... We may have to go that route per customer request. Other choices ensure that the Tin finish is Matte, bigger grain, instead of bright tin ( do not know yet how to verify that), have at least 3% Pb or 3-5% Bi( use of XRF) , CC assembly, annealing components, reflow assembly, immersion Tin finish.... My understanding of Immersion tin is that it does not promote Whiskers. The problem that I know about this finish, ImSn, is that it is too thin and IMC form to make it unwetable. Thanks for your sharing, Regards, Ramon -----Original Message----- From: Whittaker, Dewey (AZ75) [mailto:[log in to unmask]] Sent: Friday, March 24, 2006 10:39 AM To: TechNet E-Mail Forum; Dehoyos, Ramon Subject: RE: [TN] Tin Whisker Mitigation Ramon, Yes. Don't do it and spare yourself the cruel and unusual punishment. Depending on your customers and critical end-use applications, the amount of effort to do this and control it is incredible. It can be done, but it extracts a heavy toll. Even meager efforts in-house with chips is a waste of dough( now class did you catch the joke? Toll house morsels = Chips( chocolate) = waste of dough. Good you earned your chocolate chip cookie). Dewey -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Dehoyos, Ramon Sent: Friday, March 24, 2006 8:18 AM To: [log in to unmask] Subject: [TN] Tin Whisker Mitigation Hello TechNetters: Does anyone know of companies that are replating parts with Sn63 and reballing BGAs? Could any one share their experiences in doing this effort? Things such as: extra time needed, cost, reliability....... Regards and TIA, Ramon Dehoyos, 410.552.2210 --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------