Brightener breakdown at the insoluble anode by active chlorine species during Cu electrodeposition

Abstract It is highly important to design and develop appropriate insoluble anodes for industrial Cu electroplating to lower the amount of organic additives that this process consumes. Conventionally, this rapid consumption of additives (e.g., brighteners, suppressors, or levelers) is known to be due to the active radical species (e.g., ∙OH) formed during oxygen evolution. In this study, we found that trace amounts of chloride ions present in the electroplating bath are the source of the active chlorine species that accelerate the breakdown at the insoluble anode. A sacrificial, perfluorinated polymer coating effectively decreased the emission of active chlorine species from the electrode, thereby lowering the consumption of the brightener. This study reveals that the suppression of chlorine evolution at the anode can be an effective approach for decreasing brightener consumption during Cu electrodeposition.