It sounds like there might be silica from a tap water rinse prior to your soldermask step that is causing the contamination. If you do have a rinse step, you may want to analyze the cleanliness of the water using ion chromatography. We have seen this sort of reaction on gold finished boards several times before. Contact our office offline if you want to discuss your situation in more detail. Regards, Sara Gorcos Foresite Inc. 1982 S. Elizabeth St. Kokomo, IN 46902 765-457-8095 www.residues.com [log in to unmask] -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Mike Wolf Sent: Thursday, June 02, 2005 6:43 AM To: [log in to unmask] Subject: [TN] Residue on bondable gold? We are experiencing some type of residue on PCB's with gold as a final metal finish. The residue adversely affects wire bonding to the gold. The residue is present on both in-house fabbed boards and outside vendor fabbed boards. It appears to be related to the soldermask in that there are recognizable patterns (bubbles maybe) in the soldermask, that are visible in the residue on the gold. An aggressive plasma cycle loosens the residue (does not remove) but at same time attacks the FR4 & Smask. No amount of solvent cleaning removes the residue. Nor does ultrasonics. Our in-house fab is electro- Copper, Nickel, & Gold, I'm pretty sure the outside vendors are using ENIG. We vacuum bake all our bds as a precaution to avoid die attach bleedout. Could this bring to the surface problems we might not otherwise see? Has anyone else seen this type of residue? Know what it is or how to get rid of it/prevent it? Michael Wolf EH&S Manager EVI Technology LLC 7138 Columbia Gateway Drive Columbia MD 21046 Phone # 443-542-2826 Fax # 410-290-1925 [log in to unmask] www.evitechnology.com --------------------------------------------------- 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 -----------------------------------------------------