This is common with ENIG. The issue is a build up of potential that displaces the catalyst in the nickel deposition leaving a skip plating condition. The issue is found on common nets that are connected to PWR layers and more prevalent on these nets with longer runs. We have some blind/buried via products that simply will not process in ENIG and we have switched these to silver. Jeffrey Bush Director, Quality Assurance and Technical Support VERMONT CIRCUITS INCORPORATED 76 Technology Drive - POB 1890 Brattleboro, Vermont 05302 Voice - 802.257.4571 ext 21 Fax - 802.257.0011 <http://www.vtcircuits.com/> -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Dan Skweres Sent: Monday, September 18, 2006 5:54 PM To: [log in to unmask] Subject: [TN] ENIG We have, at times, had an outside plating service have difficulties with plating of ENIG on our bare boards. The interesting anomaly we have encountered is lack of plating on certain pads. They tell us there is something on the surface of the pads but when they return the panels to us we micro etch (copper looks beautiful) and all pads look similar in appearance. We even took a panel and coated immersion white tin with out problems. This tells me that there isn't any thing on the surface of the copper. There is one thing I did leave out. The pads that aren't taking ENIG all happen to be in the same net. Has anyone encountered this? It's almost like there is a charge being created in certain nets not allowing the ion exchange to happen. Could it be entrapped chemistry within vias? Any help and/or direction would be greatly appreciated. Thanks, Dan Skweres Engineering Manager Bartlett Manufacturing Phone:847-639-2102 Ext.#230 Fax:847-639-8838 --------------------------------------------------- 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 -----------------------------------------------------