Gold Wire Bondability of Electroless Gold Plating Using Disulfiteaurate Complex

摘要

Gold wire bondability of non-cyanide electroless gold plating using disulfiteaurate complex was investigated. Generally, printed wiring boad is fabricated by subtractive or additive process. After fabricate the circuits, contact or terminal areas were usually coated with nickel and gold for maintaing reliability between printed circuit and another electrical functional parts. Usually, diluted palladium solution is adopted to initiate electroless nickel plating on a copper circuits. However, selectivity of nickel deposition on a resin based copper circuits is not good enough by treatment diluted palladium solution as an activator. Selectivity was greatly improved by treatment with strong reducing agents such as SBH, DMAB or TMAB. Bondability was greatly influenced by the contents of phosphorus in the deposited nickel. Gold crystal orientation was also affected by the gold wire bonding, and high bonding strength was obtained with (220), and (311) preferred oriented electroless gold films.