Synergetic Effect of 1,2,4-triazole and Glycine on Chemical Mechanical Planarization of Aluminum at Low Polishing Pressure in an Eco-Friendly Slurry

• Published in: ECS journal of solid state science and technology Vol. 9; no. 3; pp. 34003 - 34011
• Main Authors: Sun, Ping, Wang, Yongguang, Liu, Ping, Zhu, Yuguang, Zhao, Yongwu, Zhao, Dong, Deng, Hui
• Format: Journal Article
• Language: English
• Published: IOP Publishing 28.02.2020
• ISSN: 2162-8769; 2162-8777; 2162-8777
• DOI: 10.1149/2162-8777/ab7882

In this paper, glycine and 1,2,4-triazole (TAZ) are used as eco-friendly additives to compensate the decrease in removal rate owing to the low polishing pressure in chemical mechanical planarization (CMP) of aluminum (Al) at near-neutral pH value. It demonstrated that the synergetic effect of glycine and TAZ participates in the formation of a weak passive layer with the hardness of 0.419 GPa on Al surface, which is compact enough to protect the Al surface from chemical dissolution and meanwhile relatively weak enough to achieve high polishing rate. Even at a low polishing pressure of 1.0 psi, a material removal rate of 750 nm min−1 with surface roughness of 0.19 nm was obtained in an eco-friendly slurry at pH 7.5. It was found that the weak passive layer is physicochemical formed on surface of Al with Al-TAZ bonds, which is subsequently complexed by glycine with Al-COOH bonds verified by Langmuir isotherm theory and X-ray photoelectron spectroscopy test. The above two synergistic parts are integrated into the material removal process. The material planarization mechanism in CMP process of Al was discussed as well.