The data that I've seen on this subject indicates that very smooth Ni/Au
surfaces wire bond poorly.  On the other hand, an extremely rough Ni/Au
surface also exhibits poor wire bond pull strengths.  In general, it seems a
"moderately rough" Ni/Au surface provides the best results.

Rob Schetty
LeaRonal Inc.


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A question came up on what the surface finish (smoothness/roughness) should
be for wire bond on a land.  The plated finsh is typically nickel and a
covered with a soft gold finsh.  Will hills and valleys in the surface make
any difference in the bond strength.

Phil Hinton
hintpwb1@aol,com