Investigation of Removal Mechanism of Sapphire in Plasma Assisted Polishing

Abstract:

Single crystal sapphire is widely used as the material for precision equipments, due to its high hardness, chemical inertness and light transmission. However, it is difficult to obtain a scratch-free and damage-free sapphire surface with high-efficiency through traditional mechanical polishing or etching. We developed plasma assisted polishing (PAP) for the finishing of difficult-to-machine materials, such as silicon carbide, diamond, and sapphire. In this article, preliminary research results are showed about PAP applied to polishing of single crystal c-plane sapphire substrates. Combination of helium based atmospheric pressure water vapor plasma irradiation and silica abrasive polishing drastically increased removal rate of the sapphire c-plane. XPS measurements of the surfaces with and without irradiation of water vapor plasma revealed that alumina hydrate was formed by plasma irradiation at low temperature of less than 40°C. It is assumed that formation of alumina hydrate promoted the removal rate of sapphire.

• Periodical: Key Engineering Materials (Volume 625)
• Pages: 458-462
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.625.458
• Online since: August 2014
• Authors: Kohki Monna, Hui Deng, Katsuyoshi Endo, Kazuya Yamamura*
• Keywords: Atmospheric Pressure Plasma, Hydration, Polishing, Sapphire, Silica Pellet

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