Processes of bump deposition based on mechanicla procedures together with their reliabiltiy data are summarized in this paper. The stud bumping of gold, palladium, and solder is described and also a novel bumping approach for fine pitch solder deposition down to 100 μm pitches using thermosonic bonding on a modified wedge-wedge bonding machine. This wedge bumping doesn't require a wire flame-off process step. Because of this, no active atmosphere is necessary. The miniumum pad diameter which can be bumped using the solder wedge bumping is 50 μm, up to now. This bumping process is highly reprduible and therefore well-suited for different flip chip soldering appications. palladium stud bumps provide a solderable under bump metallization. Resuts from aging of lead/tin solder bumps on palladium are shown. The growth of intermetallics and its impact on the mechanical reliabilty are investigated.
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