Gold cyanide ([Au(CN)2]-) solution releases free cyanide ions during plating process. The toxicity will seriously endanger the health of the production personnel and natural environment. In addition, they will cause certain damage to the photoresist. Therefore, cyanide-free electrolytes have been developed in recent years. Based on the analysis of more than 50 references, the composition, operating conditions, electrodeposition mechanism, advantages and disadvantages of various sulfite gold ([Au(SO3)2]3-), thiosulfate gold ([Au(S2O3)2]3-) and their mixed electrolytes, and other sulfur-based cyanide-free gold plating electrolyte systems were summarized. The research trend and development direction of soft gold electroplating technology based on cyanide-free ligand electrolyte were prospected. |