As co-chairman of the 4552 committee, I must take exception to your comment" It does not contain a lot of useful detail". For this specification extensive testing was performed and data presented , paper appeared in the last issue of IPC review as well as in the Orlando fall conference. The specification for ENIG is 2 micro inches minimum Au at -4 sigma from the mean and 120 to 240 microinches for the nickel. As a point of note, I tested two days ago samples from two of the five vendors that supplied samples for wetting balance testing that were used to generate this specification. The samples are now 14 months old (they have been lying around my office not protected) and for the test we had them plated with 1 microinch of gold. THEY STILL SOLDER AND PASS ALL WETTING BALANCE CRITERIA!!! The degree of porosity at 1 microinch is obviously greater than at 5 microinches however the protection afforded the underlying nickel is still excellent, solderability testing was with a ROL0 type flux per j-std 004. It is intention of the 4552 committee to publish the total data set as a TR report. If anyone would like a copy of testing specifics or a copy of a specific test data set - XRF , wetting balance, contact resistance , please feel free to contact myself, George Milad -chairman of the committee or Tom Newton at the IPC Regards Gerard O'Brien Photocircuits Corp. -----Original Message----- From: [log in to unmask] [SMTP:[log in to unmask]] Sent: Wednesday, January 30, 2002 10:04 PM To: [log in to unmask] Subject: Re: [TN] ENIG Thickness Standard? 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. 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