Hi, Yehuda, There have been countles posts on this subject in the past, and a trawl through the archives searching for either HASL or ENIG should yield you more reading material than you can comfortably handle this side of Christmas. Simply, though, I use both finishes on boards in a single piece of equipment. I chose HASL for boards that don't contain any BGA's or other components that require a particularly flat mounting surface, and ENIG for boards with BGA's on them. At the time ENIG was known to have possible problems (the dreaded Black Pad), but the causes and cures were also known. Overall, if the problems could be avoided, ENIG seemed to be the best finish for my application. An alternative that provided equally good flatness was Immersion Tin, but I was shy of this because of all the talk of whiskers, oxidation and other issues that I didn't want to get into. ENIG, properly done, seemed stable and durable for boards that were possibly going to be around for a while before being soldered. Given a new-design project, I would now look at something like Immersion Tin for everything, to have a common finish and to avoid the hot dip process involved in HASL coating. The whiskers issue, such as it was, now seems to have been largely overcome. I am still in the PbSn solder game for my Class 3 boards, and use pretty large BGA's by current standards - 35mm square with 1.27mm pitch - but we'll use smaller ones, no doubt, as time goes on. Peter Ervin Weisz <[log in to unmask]> 30/05/2003 05:38 AM Sent by: TechNet <[log in to unmask]> Please respond to "TechNet E-Mail Forum."; Please respond to Ervin Weisz To: [log in to unmask] cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group) Subject: [TN] Enig? HASL? Dear Technetters, As many others, I am considered about the "ENIG vs. HASL vs. another few finishes". I wonder what do people specify in those industries that require 0 failures: defense industry, automotive, aerospace, etc. Mainly, I would like to know what do companies in such fields specify for boards that are populated with small BGAs (0.032" pitch and lower), also known as CSPs.Boards that have very high reliability requirements and have advances packages - what surface finish is required/recommended for the boards ?? I would appreciate links to existing specs., personal information, or anything you can spare on this subject. Thanks, Yehuda Weisz Process Engineer - PCB production Do you Yahoo!? --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- Free online calendar with sync to Outlook(TM). [This e-mail is confidential and may also be privileged. If you are not the intended recipient, please delete it and notify us immediately; you should not copy or use it for any purpose, nor disclose its contents to any other person. Thank you.] --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------