Rick, I went through this pain a while ago, and got a lot of tremendous help from Ingemar Hernefjord in particular. I believe there is no released standard for ENIG, though there is an empirical spec IPC-4552. It does not contain a lot of useful detail, though. I specify 5 microinches (0.12 microns) of Gold over minimum 235 microinches (6 microns) Nickel for my boards, after reading a number of studies and failure reports. In fact I was recommended to use 250 microinches of Nickel, but this would have made our boards too thick. The thicker gold layer minimises porosity and therefore oxidation to the underlying Nickel layer. Older thinking was for around 100 to 120 microinches Nickel, but studies by Eriksson and others concluded that with the growth of gold flashing through the Nickel from one side and Cu/Ni intermetallics on the other side of the plating, that a thicker Nickel layer would offer the boards a longer solderability shelf life and greater solder joint reliability. Hope this helps a bit. Certainly, I haven't experienced any problems with soldering or mounting of components on boards to this spec. Peter Rick Thompson <rthompson@VENTURAELECTR To: [log in to unmask] ONICS.COM> cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Sent by: TechNet Aero/ST Group) <[log in to unmask]> Subject: [TN] ENIG Thickness Standard? 01/31/02 08:36 AM Please respond to "TechNet E-Mail Forum."; Please respond to Rick Thompson Is there a standard for the plating thickness of the ENIG surface finish? I've searched the archives and didn't find anything. Based on a customer request we had increased the requirement for the electroless nickel to 200u inches. A couple of our board vendors are telling me that that is excessive and that anything over 100u inches is overkill. I've seen references in the archives for anything from 120u inches to 200u inches. What (if anything) is considered standard for this finish? Thanks for your inputs. Rick Thompson Ventura Electronics Assembly 2655 Park Center Dr. Simi Valley, CA 93065 +1 (805) 584-9858 x-304 voice +1 (805) 584-1529 fax [log in to unmask] --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 --------------------------------------------------------------------------------- [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 1.8d 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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 ---------------------------------------------------------------------------------