Influence of Nano Abrasive on Chemical Mechanical Ultra-Precision Machining of Sapphire Substrate Surfaces

Abstract:

Sapphire (α-Al₂O₃) single crystal combines many good mechanical and optical properties that make it become the material of choice in a variety of modern Hi-Tech applications The use of CMP technique can produce high quality surface finishes at low cost and with fast material removal rates. In CMP process, nanoabrasive is very important parameters in determining the removal rate. In this paper, the influence mechanism of nanoabrasive on sapphire substrate CMP was analyzed deeply. The main kinetics processing was discussed in detail. According to sapphire substrate properties, alkali slurry was chosen and the mix of SiO₂ and Al₂O₃ sol was selected as nanoabrasive, and the particle size was 20~30nm. The results show that adding nanoalumina with the concentration of 20ml / L in the main abrasive can make the chemical action balance with the mechanical action in the CMP process, so that the substrate removal rate is well improved, and the surface roughness can be reduced to 0.236nm by adjusting the process parameters and slurry ratio. Such data meets the super smooth requirement and the optimal sapphire surface can be gotten. So such slurry with mixed abrasive can be as rough polishing slurry and can improve the polishing efficiency.

• Periodical: Key Engineering Materials (Volumes 609-610)
• Pages: 130-134
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.609-610.130
• Online since: April 2014
• Authors: Xin Huan Niu, Ya Huan Huang, Jian Wei Zhou*, Li Ying Han, Gai Hong Yuan
• Keywords: Chemical Mechanical Polishing, Nanoabrasive Slurry, Removal Rate, Roughness, Sapphire Substrate

References

[1] Wang Chonglu， Sapphire single crystal， Tianjin Science and Technology Press，Tianjin，(1983).

[2] BoAAkowski M. Growth of GaN on patterned GaN/sapphire substrates by high pressure solution method, Journal of Crystal Growth, 281(2005) 11-16.

DOI: 10.1016/j.jcrysgro.2005.03.008

[3] Yanhui Xing. Investigation of GaN layer grown on different low misoriented sapphire by MOCVD, Applied Surface Science, 255(2009) 6121-6124.

DOI: 10.1016/j.apsusc.2009.01.063

[4] Shengjun Zhou. Study on sapphire removal for thin-film LEDs abrication using CMP and dry etching, Applied Surface Science, 255(2009)9469–9473.

DOI: 10.1016/j.apsusc.2009.07.063

[5] A.V. Borodin，Advanced technologies of shaped sapphire fabrication，Journal of Crystal Growth， 310(2008)2141–2147.

DOI: 10.1016/j.jcrysgro.2007.11.202

[6] Wenhu, Xu, Xinchun Lu, Effects of the ultrasonic flexural vibration on the interaction between the aboraive particles, pad and sapphire substrate during chemical mechanical polishing, Applied Surface Science, 257(2011)2905-2911.

DOI: 10.1016/j.apsusc.2010.10.088

[7] Niu Xinhuan. High Precision Finishing Technique of Sapphire Substrate Surface for Photoconducting Device, Materials Science Forum, 663-665(2011)80-83.

DOI: 10.4028/www.scientific.net/msf.663-665.80

[8] Hideo Aida , Toshiro Doi , Hidetoshi Taked, et al. Ultra-precision CMP for sapphire, GaN, and SiC for advanced optoelectronics materials ，Current Applied Physics，12(2012)S41-S46.

DOI: 10.1016/j.cap.2012.02.016

[9] Jiecai Han, Changqing Li, An investigation of long pulsed laser induced damage in sapphire, Optics & Laser Technology, 41(2009)339-344.

DOI: 10.1016/j.optlastec.2008.05.026

[10] Honglin Zhu, Luiz A. Tessaroto and Robert Sabia. Chemical mechanical polishing(CMP) anisotropy in sapphire. Applied Surface Science, 236 (2004) 120-130.

DOI: 10.1016/j.apsusc.2004.04.027

[11] N.H. De Leeuw, S.C. Parker, Effect of chemisorption and physisorption of water on the surface structure and stability of alpha-alumina.J. Am. Ceram. Soc. 82 (1999) 3209–3216.

DOI: 10.1111/j.1151-2916.1999.tb02225.x