Direct immersion gold (DIG) as a final finish

Purpose To report on research on the alternative surface finish “direct gold on copper”, including reaction mechanism, methods of deposition and end uses. Design/methodology/approach Examines the deposition reaction of the electroless flash gold plating bath, and the effects of the copper surface roughness and deposition time on the deposit and solderability characteristics. Findings Direct immersion gold is only partially immersion and mostly electroless in deposition mode. The surface is applicable to soldering for both leaded solder and lead‐free solders. The surface is also wire bondable. Originality/value The paper offers details of a new alternative surface finish for use in printed circuit board fabrication as well as in packaging applications. The paper shows the electroless deposition mode of the process. The finish is ideally suited where Rf losses must be minimized. It is suitable for soldering as well as for wire bonding.