Mechanistic Insights into the Durability of IrO2–Ta2O5 DSA Influenced by Organic Additives in a Copper Electroplating System

In copper electroplating systems, the mechanisms by which organic additives shorten the service life of dimensional stable anodes (DSAs) remain unclear, hindering rational anode and additive design. Here, we investigated the effects of three representative additives—brightener (SPS), suppressor (PEG), and leveler (Collagen)—on IrO₂–Ta₂O₅ DSAs using accelerated lifetime tests, XPS, and DFT calculations. The experimental results showed that all additives reduced electrode durability, with collagen showing the most pronounced effect, shortening lifetime by over 40%. Adsorption of additives increased OER overpotential and accelerated Ir dissolution, leading to decreased electrochemically active surface area and activity. DFT and XPS revealed that collagen and similar N-containing levelers strongly adsorb on IrO₂(110), consistent with their high degradation effect, whereas SPS had minimal impact. Similar adsorption trends were observed on RuO₂(110) and SnO₂(110), suggesting broader relevance. These results clarify additive-induced degradation mechanisms and provide guidance for mitigating durability loss, including optimizing additive concentration and improving oxide coating design.