Improvement of oxide chemical mechanical polishing performance by increasing Ce3+/Ce4+ ratio in ceria slurry via hydrogen reduction. (1st June 2023)

• Record Type: Journal Article
• Authors: Lee, Jaewon; Kim, Eungchul; Bae, Chulwoo; Seok, Hyunho; Cho, Jinil; Aydin, Kubra; Kim, Taesung
• Is Part Of: Materials science in semiconductor processing. Volume 159(2023)
• Publication Date: 2023-06-01
• Subjects: Ceria abrasive -- Hydrogen gas -- Reduction -- Chemical mechanical polishing (CMP); Semiconductors -- Periodicals; Integrated circuits -- Materials -- Periodicals; Semiconducteurs -- Périodiques; Circuits intégrés -- Matériaux -- Périodiques; Electronic journals; 621.38152
• DOI: 10.1016/j.mssp.2023.107349
• Languages: English
• ISSNs: 1369-8001

Abstract

Abstract: Ceria-based abrasive is widely used in the oxide chemical mechanical polishing (CMP) process due to its high polishing performance. Ce 3+ ions on the surface of ceria form a Ce–O–Si chemical bond with surface of the SiO2 wafer, significantly affecting the material removal rate (MRR). In this study, the ceria surface was reduced by contact with hydrogen gas in a high temperature isothermal environment. Hydrogen gas forms surface hydroxyls on the ceria. Then, the generated hydroxyls form H2 O and oxygen vacancies occur through the desorption of the H2 O. The color of ceria changed to blue due to a change of the crystal structure by the reduction reaction. The reducing ability of hydrogen gas increased as the reduction temperature increased and the Ce 3+ ion concentration increased by 12.7% under isothermal conditions at 1000 °C. The MRR of reduced ceria was improved by up to 37.7% compared to the original ceria. Graphical abstract: Image 1 Highlights: The ceria particles were reduced by hydrogen gas in a high temperature environment. Oxygen vacancy was formed through hydrogen adsorption and H2 O desorption processes. Ce 3+ ion concentration increased as the reduction temperature increases. The oxide removal rate was significantly affected by Ce 3+ ion concentration.