<!DOCTYPE HTML PUBLIC "-//W3C//DTD W3 HTML//EN"> <HTML> <HEAD> <META content=text/html;charset=iso-8859-1 http-equiv=Content-Type> <META content='"MSHTML 4.72.2106.6"' name=GENERATOR> </HEAD> <BODY bgColor=#ffffff> <DIV><FONT color=#000000 size=2>Okay brainiac's, here's a stumper.</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>We are witnessing micro-etch attacking exposed copper circuitry only on boards with gold tabs.</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>This occurs right at the copper to gold demarcation point.</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>This only just started, within two days.</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>No significant process changes have occurred. (normal replenishments, all data looks nominal)</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>We first noticed it after we stripped off some poor white tin for rework. When we inspected the boards before</FONT></DIV> <DIV><FONT color=#000000 size=2>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.</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>From our supplier, they believe the gold is reacting with chemistry in the micro-etch bath??????</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>Has anyone else witnessed this? And how'd you resolve it?</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>Thanks,</FONT></DIV> <DIV><FONT color=#000000 size=2></FONT> </DIV> <DIV><FONT color=#000000 size=2>Franklin</FONT></DIV></BODY></HTML>