In this study, the DIG process (Direct Immersion Gold), is investigated. DIG is a process in which gold is plated directly on copper as a surface finish for printed circuit board and package applications. By examining the deposition reaction of the electroless flash gold plating bath, it was confirmed that, copper does not co-deposit with gold and also that the main driving force for deposition is an autocatalytic reaction. In addition the effects of the copper surface roughness and deposition time on the deposit and solderability characteristics were examined. It was determined that copper surface roughness affects solder spread-ability, and that solder joint characteristics were excellent when the film thickness is within the range of 30 to 80 nm. Furthermore, good wire bonding characteristics were confirmed from deposits plated by a neutral pH, autocatalytic type heavy electroless gold plating bath, atop the flash gold.
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