The palladium plating is used in semiconductor lead frame as Pd-PPF(Palladium Pre Plated Leadframe), when the palladium plating is plated for an IC product, the solder plating process in the assembly process can be omitted.
The palladium plating is usually used as three layer plating of Ni-Pd-Au.
The palladium plating functions as a diffusion barrier of nickel and by thinning
of gold plating thickness, achieve a cost reduction and a good wire bondability,
a good solderability.