Experimental study on ultraprecision polishing for ultrathin quartz substrates

SUN Lei, GUO Weigang, YUAN Julong, DENG Qianfa, FENG Ming, LV Binghai
(Ultraprecision Machining Research Center, Zhejiang University of Technology, Hangzhou 310014, China)

Abstract: In order to solve processing problems of the high surface quality of the ultrathin substrates, and searching for a high efficiency and low cost manufacturing processing method, a new ultraprecision polishing process was applied to the process of ultrathin quartz substrates. The principle of the polishing process was given, the optimal conditions for the lapping and polishing process were formulated. A detailed analysis was done on the roughness and thickness of the ultrathin quartz substrates, the influence of particle size on the surface roughness and material removal rate was discussed. The material removal mechanism in the process of ultraprecision polishing was also discussed. The surface roughness and thickness were used as the evaluation target, and the processing characteristics and surface quality of ultrathin quartz substrates were evaluated. The experimental results indicate that an extremely smooth surface of the quartz substrate is obtained in the ultraprecision polishing process, the ultrathin quartz substrates with thickness is 99.4μm and the best surface roughness is Ra 0.82nm. The surface residual stress of the quartz substrates can be reduced by increasing the polishing time, at the same time, the flatness and parallelism can be controlled very well.
Key words: quartz substrate; ultraprecision polishing; surface quality; material removal mechanism