Feasibility of water film adsorption positioning in sapphire polishing
                                     CHEN Zhen hua, CHEN Zhi xiang, GAO Tao, YUAN Ju long, ZHAO Tian chen, HANG Wei
（1.Ultraprecision Machining Center, Zhejiang University of Technology, Hangzhou 310014, China;2.China United Engineering Company, Hangzhou 310052, China）

Abstract: Aiming at the problems on polishing quality and cost in sapphire polishing which uses paraffin pasted clamping and polishing adsorption pad clamping, water film clamping was put forward. The tangential adsorption force and normal adsorption force of the adsorption surface on sapphire wafer were measured, and compared with the tangential adsorption force and normal adsorption force under polishing adsorption pad respectively. And the tangential force was used as the main evaluation quota. The feasibility of using water film adsorption clamping for sapphire polishing was judged. The results indicate that only from the perspective of the adsorption ability, it is feasible to use water film clamping; 45#steel is more suitable to be the substrate material than glass; the surface roughness of the sapphire wafer should be considered when the surface roughness of the substrate is identified.

Key words: sapphire; polishing; clamping method; water film adsorption