###### Abstract  
Cu interconnect chemical mechanical polishing (CMP) technology has been continuously evolving, leading to increasingly stringent post-CMP cleaning requirements. To address the environmental pollution caused by traditional post-CMP cleaning solutions, we have explored the use of photocatalytic processes to remove citric acid, which is a commonly used complex agent for CMP. In this study, CeO2 abrasives, characterized by a hardness of 5.5, are extensively employed in CMP. Importantly, CeO2 also exhibits a suitable band structure with a band gap of 2.27 eV, enabling it to photocatalytically remove citric acid, a commonly used complex agent in Cu CMP. Additionally, the integration of H2O2, an essential oxidant in Cu CMP, enhances the photocatalytic degradation efficiency. The research indicates that the removal rate of single-phase CeO2 was 1.78 mmol/g/h and the degradation efficiency increased by 40% with the addition of H2O2, attributed to the hydroxyl radicals generated from a Fenton-like reaction between H2O2 and CeO2. These findings highlight the potential of photocatalytic processes to improve organic contaminant removal in post-CMP cleaning, offering a more sustainable alternative to conventional practices. CMP; CeO2; agent citric; photocatalyst; degradation [1]Applied Sciences  
1,2,+, 2,  
post-CMP Cu cleaning process involves using highly alkaline cleaning agents with high pH to clean the polished Cu [7; 8]. While these agents can remove polishing residues, the high pH of alkaline cleaning agents poses certain risks to the environment, equipment, and human health. In the search for more environmentally friendly post-CMP cleaning methods with less impact on equipment and human health, photocatalytic processes have gained favor due to their eco-friendly, green, sustainable, energy-saving, easy-to-operate nature, broad spectrum of activity, and lack of secondary pollution [9]. In the field of the photocatalytic degradation of pollutants, [PERSON], [PERSON] et al. investigated the formation of alkyl halides from the photodegradation of small-molecule carboxylic acids in the presence of chloride and Fe(III) [10]. [PERSON], [PERSON] et al. used a dual-chamber microbial fuel cell to degrade citric acid [11]. [PERSON], [PERSON] et al. investigated the plasma-modified electrosynthesized cerium oxide catalyst for plasma and the photocatalytic degradation of RB 19 dye [12]. [PERSON], [PERSON] et al. achieved the photocatalytic degradation of relatively high concentrations of citric acid by adding H\({}_{2}\)O\({}_{2}\), Fe(III), or both to TiO\({}_{2}\) and observed a significant enhancement in the degradation rate [13]. [PERSON], [PERSON] et al. conducted a study investigating the photocatalytic performance of Ce-Ni co-doped ZnO nanodisk-like self-assembled structures synthesized via the sol-gel method for the degradation of methylene blue (MB) dye under UV irradiation [14]. The photocatalytic reaction process mainly consists of four steps: photoexcitation, carrier migration, carrier separation, and redox reactions. The core of the surface reaction is the redox reaction induced by photogenerated carriers [15]. To minimize the environmental, equipment, and human impact of post-CMP cleaning processes, this study explores the use of CeO\({}_{2}\) abrasives with suitable band structure and tribological properties, combined with the commonly used oxidant H\({}_{2}\)O\({}_{2}\) in CMP, as photocatalytic accelerators to degrade the citric acid complex agents remaining on the Cu surface after CMP [16]. This approach leverages clean energy in the form of solar power to drive the post-CMP cleaning process. By testing the degradation efficiency of citric acid under illumination, the optimal concentration and degradation rate were identified, validating the feasibility of using photocatalysis for post-CMP cleaning. In terms of reaction mechanisms, the morphology and band structure of cerium oxide were characterized, revealing a large specific surface area and numerous active sites.