Two new electrolytically plated lead-free surface finishes, satin bright tin on nickel and palladium-cobalt on nickel followed by gold flash coating, are evaluated for their wettability, bond strength, and voiding performance, and are compared with electrolytic nickel gold and OSP. Results indicate that Ni-Sn, although being sensitive to aging, and reflow atmosphere, solder alloy type, and variation in flux chemistry, it is the highest in wettability, one of the highest in lap shear strength, and the lowest in voiding. It performs better under long profile. The high sensitivity may be attributed to the relatively high reactivity of tin. Under most instances, the soldering performance is comparable with or better than the references OSP and Ni-Au. Ni-PdCo-Au is poor in wettability, fairly low in lap shear strength, and high in voiding. However, it is fairly stable, and its soldering performance is not sensitive to profile length, reflow atmosphere, aging treatment, and flux chemistry. It does seem to be sensitive to Bi-containing alloy in terms of voiding and lap shear strength. OSP is the poorest in wettability, but one of the best in lap shear strength. It performs best under long profile. It is not sensitive to reflow at mosphere, slightly sensitive to alloy type, but is very sensitive to aging and flux chemistry. Ni-Au is good in wettabilily and voiding, medium in lap shear slrength. It is not sensitive to aging, flux chemistry, reflow atmosphere, slightly sensitive to alloy type and profile length.
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