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ABSTRACT: As the laminate substrate industry moves from Hot Air Solder Level
(HASL) finishes, alternate plating finishes are being proposed such as
electroless palladium and immersion gold over electroless nickel. This
paper presents results of an evaluation of the thermosonic gold ball
wire bondability of immersion gold over electroless nickel. The initial
evaluation criteria included bondability (number of missed bonds), wire
pull strength, and bond failure mode. Different preconditioning
environments such as reflow cycles, high temperature storage and
humidity storage on initial bondability were also considered. Rutherford
backscattering, Auger spectroscopy and XPS were used to examine the gold
and nickel layers. The stability of the bonds was investigated by high
temperature storage with periodic electrical resistance and pull
strength testing
Multichip Modules, 1997., 6th International Conference on; 05/1997
