XY stage driven by ultrasonic linear motors for the electron-beam x-ray mask writer EB-X3

A new XY stage employing ultrasonic linear motors that is simple, compact, and completely nonmagnetic was developed for an e-beam x-ray mask writer employing step-and-repeat writing. The main performance results are: (1) position fluctuations during writing are less than +/-4 nm; (2) the time for a 650 mu m step movement is less than 270 ms; (3) the magnetic interference is less than +/-1 nT at the e-beam deflection center; and (4) the vibration of the stage when moving at a constant speed is less than +/-0.25 m/s(2). The new stage is also very easy to maintain. It has been installed in the EB-X3 e-beam x-ray mask writer. (C) 1999 American Vacuum Society. [S0734-211X(99)16606-X].