Chuck,

     You really need to identify the type of contamination you are dealing
     with, i.e., organic, inorganic, etc.  Then identify the source, i.e.,
     PCB supplier, internal handling practices, storage, etc.  Abrading to
     get good results can only be a short term fix and can lead to other
     problems.  Plasma can be employed to remove certain contaminants, and
     many wire bonders include a plasma burn as part of standard operating
     procedure.  Some board manufacturers have taken it upon themselves to
     perform at least an oxygen burn in plasma to remove residual organics
     prior to shipping product.  Photo resists, soldermasks and their
     associated processes can leave some organic residues behind on the
     gold surfaces.

     Hope this helps..Andy


______________________________ Reply Separator _________________________________
Subject: [TN] Wire Bonding On Gold
Author:  Chuck Garth <[log in to unmask]> at smtplink-hadco
Date:    04/20/99 6:29 AM


We are presently wire bonding aluminum wire to gold lands on circuit boards.
I have heard many times that wire bonding goes sour to clean them with an
eraser.  This seems a little primitive.  Is there any other way that this can
be accomplished.
If the eraser works why hasn't someone designed something to take care of
this.
Chuck Garth

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