This one's easy...
     Gold plate after copper plate for your "thin" requirement for
     soldering, then put another image on top of that to expose the areas
     needed for "thick" gold for wirebonding.


______________________________ Reply Separator _________________________________
Subject: [TN] Assy:  Another gold/solder question
Author:  Glenn Pelkey <[log in to unmask]> at SMTPLink-Hadco
Date:    4/28/98 9:40 AM


Hello all,

        Adding to the discussion of gold embrittlement, how would you address
the issue of maximizing gold thickness for wirebonding and minimizing gold
thickness for soldering operation on the same board surface?  In Table 3-2 of
IPC-6015, there is an acceptable range for Class 1 and 2 that can be worked
in, but with Class 3 there isn't.

        Maybe that's my answer...work in Class 1 or 2 only, specify gold
thickness, verify content, and establish influence on solder joint integrity
with respect to user environment.

        Has anyone else had to address this?

Glenn Pelkey
Maxtek Components Corp.

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