Well Bill,

I'll happily stand correction, but I think it's difficult to confirm gold
cleanliness. With copper you can try a spot of etch or flux on the copper
area, if there's mask residue then the chemical won't touch the copper,
normally you'll notice the difference between oxidised copper and the fresh
etched. With gold you couldn't get away with that. If you can get your board
into a SEM-EDX chamber you could look for organic residue on the gold
surface.

Best regards,

Andrew Hoggan
BBA Associates Ltd
www.bba-associates.com

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Bill Christoffel
Sent: 07 August 2001 14:04
To: [log in to unmask]
Subject: [TN] Contamination Concern after Strip


Input Needed !

We currently use a board that is designed for gold ball bonding (COB)
and have specified  electroplated gold as the top metal layer.  This
board also uses a Tayio solder mask material that is flood coated over
the top, including the gold pads then photo imaged/etched. to expose
specific gold pads for wire bonding.    My concern is that the solder
mask may be leaving some type of contamination on the bonding pads.   If
so, I'm looking for recommendations on how to verify cleanliness, other
than ionically (which we do) and how to remove any contamination.


Thanks,

Bill C.

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