Believe this is an issue with the immersion gold bath - there if probably just extraneous AU without a NI underplate? Jeffrey Bush Director, Quality Assurance and Technical Support VERMONT CIRCUITS INCORPORATED 76 Technology Drive - POB 1890 Brattleboro, Vermont 05302 Voice: 802.257.4571.21 Fax: 802.257.0011 http://www.vtcircuits.com -----Original Message----- From: Colin McVean [mailto:[log in to unmask]] Sent: Wednesday, March 23, 2005 3:27 PM To: [log in to unmask] Subject: [TN] Nickel Gold "step" plating Hi to all, We've just completed a batch of Polyimide multilayer PCB's and Ni/Au'd as our solderable finish. We have noticed that the Ni/Au has plated onto and around the pads, and joined up some quad pack pads. I seem to recall something about Zinc Octanoate acid leaching out from the surface of the Polyimide, which acts as a catalyst for the solution to get a grip and plate onto what is bare substrate, or have I got the wrong end of a long stick? Would a UV bump lock the substrate surface prior to the finish, or are there other remedies? (we already IR bake resist at upto 150oC prior to the application of Ni/Au) Colin McVean Production Manager Artetch Circuits Limited Tel: 01903 725365 --------------------------------------------------- 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 -----------------------------------------------------