Fe-Nx/C assisted chemical–mechanical polishing for improving the removal rate of sapphire

Xu, Li and Zou, Chunli and Shi, Xiaolei ORCID: https://orcid.org/0000-0003-0905-2547 and Pan, Guoshun and Luo, Guihai and Zhou, Yan (2015) Fe-Nx/C assisted chemical–mechanical polishing for improving the removal rate of sapphire. Applied Surface Science, 343. pp. 115-120. ISSN 0169-4332


In this paper, a novel non-noble metal catalyst (Fe-Nx/C) is used to improve the removal mass of sapphire as well as obtain atomically smooth sapphire wafer surfaces. The results indicate that Fe-Nx/C shows good catalytic activity towards sapphire removal rate. And the material removal rates (MRRs) are found to vary with the catalyst content in the polishing fluid. Especially that when the polishing slurry mixes with 16 ppm Fe-Nx/C shows the maximum MRR and its removal mass of sapphire is 38.43 nm/min, more than 15.44% larger than traditional CMP using the colloidal silicon dioxide (SiO2) without Fe-Nx/C. Catalyst-assisted chemical–mechanical polishing of sapphire is studied with X-ray photoelectron spectroscopy (XPS). It is found that the formation of a soft hydration layer (boehmite, γ-AlOOH or γ-AlO(OH)) on sapphire surface facilitates the material removal and achieving fine surface finish on basal plane. Abrasives (colloid silica together with magnetite, ingredient of Fe-Nx/C) with a hardness between boehmite and sapphire polish the c-plane of sapphire with good surface finish and efficient removal. Fe2O3, Fe3O4, pyridinic N as well as pyrrolic N group would be the catalytical active sites and accelerate this process. Surface quality is characterized with atomic force microscopy (AFM). The optimum CMP removal by Fe-Nx/C also yields a superior surface finish of 0.078 nm the average roughness (Ra).

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 14 Oct 2020 03:26
Last Modified: 02 Nov 2020 05:12
Uncontrolled Keywords: Sapphire; Catalyst-assisted chemical–mechanical polishing; Non-noble metal catalyst; Material removal rate; Step-terrace structure
Fields of Research (2008): 09 Engineering > 0912 Materials Engineering > 091299 Materials Engineering not elsewhere classified
Fields of Research (2020): 40 ENGINEERING > 4016 Materials engineering > 401699 Materials engineering not elsewhere classified
Identification Number or DOI: https://doi.org/10.1016/j.apsusc.2015.03.041
URI: http://eprints.usq.edu.au/id/eprint/39891

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