I am a process engineer for a board manufacturer and am responsible for an ENIG(electroless nickel/immersion gold) process. IPC-TM-650 (number 2.4.28.1) is the method we use to confirm adhesion of soldermask to copper and gold to nickel both electroplated and electroless/immersion plated. You are correct that the immersion gold finish should not be peeling from the electroless nickel plate. The immersion gold peeling from the electroless nickel is a one time problem I experienced. My first thoughts were to blame the gold bath. Cooler heads prevailed and the electroless nickel was examined. The result was that some of the electroless nickel bath organics were "killed off", the suspect was potential nitric acid poisoning (nitric acid is used to strip the tank of nickel and to passivate a stainless steel tank, if used). The gold solution would then severely attack the nickel deposit resulting in non-adhesion. The peeling gold disappeared when a new electroless nickel bath was prepared(same gold bath as before). Hopefully this is not too long a discussion, but it is what I have experienced. I am not sure if peeling gold is any indication of a passive nickel surface prior to immersion gold. Perhaps the chemistry vendors or others can comment on that area. Good luck and you may contact me if needed at: 602-276-1600 Russell Burdick, Process Engineer Mosaic Printed Circuits >From: J§»¶©\(allenhu\) Q80_5380 <[log in to unmask]> >Reply-To: "TechNet E-Mail Forum." <[log in to unmask]>, >J§»¶©\(allenhu\) Q80_5380 <[log in to unmask]> >To: [log in to unmask] >Subject: [TN] tape test on the IMG surface >Date: Fri, 15 Dec 2000 09:06:11 +0800 > >Dear technetters, > >There are methods to test the adhesion of platings, markings or paints,that >is, the tape test method. >Someone told me that the tape testing should not apply on the IMG surface >since the adhesion between electroless gold and nickel is weaker (because >of its deposition characteristic)than other kinds of interface. So the IMG >product failed in the tape test is normal. >I can't agree his opinion but I can't proof myself that the TM-650 did not >state that the tape test is able to test the IMG adheresion. >Anyone who could advise the adheresion test of IMG or help me to proof >"someone " is right or wrong will be deeply appreciate! > >Allen Hu _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com --------------------------------------------------------------------------------- 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 the following message: SET Technet NOMAIL 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 ---------------------------------------------------------------------------------