Hi, I remember there being a thread about this in the not to distant past (month or two). Sorry I don't have any of the messages saved. Robert Peterson mailto:[log in to unmask] <mailto:[log in to unmask]> Alternate Final Finishes, Inc. 166 Middlesex St. N. Chelmsford MA 01863 Phone (978) 251-7429 Fax (978) 251-7219 http://www.AlternateFinalFinishes.com <http://www.alternatefinalfinishes.com/> -----Original Message----- From: Franklin [mailto:[log in to unmask]] Sent: Friday, October 08, 1999 3:52 PM To: [log in to unmask] Subject: [TN] Micro-etch attacking copper when gold tabs are involved Okay brainiac's, here's a stumper. We are witnessing micro-etch attacking exposed copper circuitry only on boards with gold tabs. This occurs right at the copper to gold demarcation point. This only just started, within two days. No significant process changes have occurred. (normal replenishments, all data looks nominal) We first noticed it after we stripped off some poor white tin for rework. When we inspected the boards before the second trip through immersion tin, we saw reduced circuits, some to the point of non-existing, pads etched away far beyond anything the micro-etch should be capable of in the seconds we keep product in this bath. From our supplier, they believe the gold is reacting with chemistry in the micro-etch bath?????? Has anyone else witnessed this? And how'd you resolve it? Thanks, Franklin