Definition

Electroless Nickel Electroless Palladium Immersion Gold (ENEPIG) is a three-layer finish: electroless nickel (3-5 µm), electroless palladium (0.05-0.15 µm), and immersion gold (0.03-0.05 µm). The palladium layer prevents black pad defects seen in ENIG and improves wire bondability for gold and aluminum wire. ENEPIG is preferred for mixed-assembly boards requiring both soldering and wire bonding, though it costs more than ENIG.