Interaction mechanism of Al 2 O 3 abrasive in tantalum chemical mechanical polishing

• Published in: RSC advances Vol. 14; no. 40; pp. 29559 - 29568
• Main Authors: Lei, Rui, Jiang, Liang, Zhang, Honglin, Chen, Yushan, Zheng, Jiaxin, Sun, Junhui, Zhao, Qijian, Qian, Linmao
• Format: Journal Article
• Language: English
• Published: England 12.09.2024
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/D4RA03743J

Al O abrasive is expected to enhance chemical mechanical polishing (CMP) efficiency compared to the SiO abrasive. However, Al O powder has dispersion issues and the material removal mechanism by Al O remains unclear. This study investigated the role of Al O abrasive in the tantalum CMP. It is revealed that (NaPO ) can effectively disperse Al O powder in water. PO improves the stability while Na deteriorates it. The total Na concentration should be lower than the turning point to attain high stability. With stable Al O -containing slurries, a relatively high material removal rate of tantalum can be obtained at an alkaline pH. The characterization results indicate that the Ta element can be adsorbed on Al O probably due to the chemical interaction between Al O and the tantalum surface. Moreover, the Al O microsphere tip starts to remove tantalum at 0.48 GPa, which is much lower than the yield strength of the tantalum surface film. For the mechanism, tantalum can be oxidized by H O at alkaline pH. When Al O presses and slides on the tantalum surface, tribochemical reactions occur, forming a chemical bond of Al-O-Ta at the interface. As Al O moves, the bond is stretched and tantalum is detached. The findings provide mechanistic insight into Al O abrasive in CMP.