John, I will mimic what Steve says to the letter. I also agree with Ingemar and will add that while you can Al wire bond to nickel plate successfully the immersion Au provides a reasonable barrier to minimize Ni oxide growth which, while slow growing, is quite tough to dissipate, even with ultrasonics, hence Ingemar not recommending it. Therefore the Au provides good preservation of the Nickel surface, especially if there is a solder reflow operation where the elevated temperature will dramatically speed Ni oxide growth. Regards, Bruce Misner -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of John Parsons Sent: Wednesday, January 12, 2005 6:32 PM To: [log in to unmask] Subject: [TN] FAB - Al Wire Bonding Greetings all, I am trying to learn something about the wire bonding process. Our customer has a part on which they spec the finish of some edge connector fingers as "Gold Plated for Wire Bonding Al Wire". As we do not provide a wire bondable gold finish in-house we have subcontracted the service. The plating service tells me that typically for Al wire bonding all that is required is a typical ENIG process (5-10u" Au over 200u" Ni). I believe that in past verbal communications with the customer they have said that an ENIG finish would not suffice and that they require 15u" of bondable gold (electroless gold or electroplated??) . What say you? Or does "it depend" :-) Regards John Parsons --------------------------------------------------- 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 -----------------------------------------------------