Bill,

As you are specifying electrolytic gold for the wire bonding, the design MUST
be bussed together to deposit gold (or the nickel gold is plated before the
copper circuit traces are formed).  In any case, if you can electroplate the
gold, you can electroplate the nickel.  It is faster and cheaper to
electroplate the nickel (even though my company sells electroless nickel).

You may have a bit of confusion between nickel gold for surface finish and
nickel gold for tab connection or wire bonding.  The proposed 4552 standard
for nickel gold for surface finish is oriented toward soldering.  You can
wire bond to electroless nickel/immersion gold, but you do not get the
thckness of gold you specify.

I suggest you electroplate the nickel if the gold is what you want, or else
greatly reduce the gold thickness to make the electroless nickel/immersion
gold process possible.

Denny Fritz
MacDermid, Inc.

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