Ultraprecision Machining Utilizing Numerically Controlled Scanning of Localized Atmospheric Pressure Plasma

By the application of atmospheric pressure plasma, we have developed a new ultraprecision machining method named plasma chemical vaporization machining (CVM). In this method, several types of rotary or pipe electrodes are prepared for optimizing the required machining. In particular, by rotating the electrode in a high-pressure environment, both the supply of reactive species to the machining point and the exhaust of reaction products are effectively performed. In the case of fabricating a grazing-incidence total-reflection X-ray mirror, figuring accuracies of 3 nm (p–v) or less were achieved and a nearly diffraction-limited focusing performance was realized. As a result of the correction of the thickness distribution of the AT cut quartz crystal wafer, thickness uniformity was improved to a 10 nm level, and resonance property was also markedly improved without degradation by high-energy ion bombardment.