Ultraprecision Finishing Process for Improving Thickness Distribution of Quartz Crystal Wafer by Utilizing Atmospheric Pressure Plasma

A new machining process was developed which is named plasma chemical vaporization machining (PCVM) for improving the thickness uniformity of thin quartz crystal wafer. This process utilizes atmospheric pressure plasma, and has excellent performances in removal rate and spatial resolution of the machining. In this process, thickness distribution of the quartz crystal wafer is corrected by numerically controlled machining. By using our correcting process, thickness distribution of an AT cut quartz wafer was improved from 270 nm to 50 nm. And spurious mode in the resonance curve was reduced by improving the parallelism of the quartz crystal wafer