Hi technetters,

Does anybody know the purpose of a palladium layer between the Ni and Au for
wire bonding PCB? Recently, I've got a request to bond gold wire
(thermosonic) on PI flex which is plated with electroless Ni and immersion
Au. On one sample, the gold thickness is reduced and compensated by a
electroless palladium layer above Ni; while the other just is the normal
electroless Ni and immersion Au. The phosphorus contect is around 6-8%.

I would appreciate if anyone can advise me on the palladium function, cost
implication (cheaper by reducing the gold?), and bondability of this kind of
metalization.

Regards, Benny.
ASM Assembly Automation
Email :[log in to unmask]

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