Static and Dynamic Characteristic of Aerostatic Porous Thrust Bearings with Deep Feed Groove

Abstract

Recently, lithographic technologies using electron-beam (EB) or extreme ultra violet (EUV) illumination source have been developed as a next generation advanced lithography. Generally, aerostatic bearings have been used in the lithography machine because they have a very higher accuracy of motion. However, lithography technologies using EB or EUV illumination source have to operate in a high vacuum and require higher precision accuracy than current lithography technology. Therefore, in this paper, an aerostatic porous bearing with deep feed groove is proposed to achieve required accuracy in the next generation lithography technology. Aerostatic porous bearing have relatively high stiffness and higher damping coefficient than another types of aerostatic bearings. In addition, the proposed bearings can supply pressurized air from a stationary guide-way to a moving table through a deep feed groove without any disturbances of air supply tubes. The static and dynamic characteristics of aerostatic porous bearings with a deep feed groove are investigated theoretically and experimentally.