I would not recommend mask over ENIG due to issues with entrapment of contaminated and possible performance issues in duty cycle. Early acrylated LPI had issues with chemical resistance to gold baths, particularly electrolytic gold and suppliers began producing toughened materials to resist attach. I have not heard of this issue in several years - what type of mask do they use? 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: Stephen Gregory [mailto:[log in to unmask]] Sent: Wednesday, May 11, 2005 9:33 AM To: [log in to unmask] Subject: [TN] LPI adhesion on ENIG vs. copper... Mornin' all you 'Netters! Gotta question. We're getting a board quoted to buy, and the shop has come back for some relief on some notes on the drawing that state: Process Notes: 1. Plate all exposed areas with Electroless Immersion Gold Nickel 100 microinches thk., Gold 2-10 microinches thk. min. 2. Apply LPI soldermask over bare copper (SMOBC) Color: Green Conform to IPC-SM-840, Class H Current rev. Resizing of soldermask pad clearances may be required due to suppliers choice of material and/or process. soldermask clearance for vias to be .004 larger than drill hole. The fab house is asking to plate the whole board with ENIG, and then apply the soldermask because they say that the ENIG process after applying the LPI will make the mask look ugly. I know the ENIG process can be tough on soldermasks, but I thought that problem has already been worked out... I gues my real question is; is the adhesion of LPI over ENIG any worse or better than SMOBC? My gut feel is to tell the fab house to comply with the notes on the drawing, I really don't want to ask our customer if the fab house can deviate from the notes on the drawing. But on the other hand, I don't want to get a raggedy looking board from them if they don't have their ENIG processes in control... Kind regards, -Steve Gregory- Senior Process Engineer LaBarge Incorporated Tulsa, Oklahoma (918) 459-2285 (918) 459-2350 FAX __________________________________________________________________ This message may contain information that is privileged and confidential to LaBarge, Inc. It is for use only by the individual or entity named above. If you are not the intended recipient, you may not copy, use or deliver this message to anyone. In such event, you should destroy the message and kindly notify the sender by reply e-mail. --------------------------------------------------- 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 -----------------------------------------------------