| 摘要 |
<p>PROBLEM TO BE SOLVED: To enable stable fine positioning operation at a high speed, by installing electromagnets for levitation which levitates and retains a stage, and a linear motor stator which positions the stage in the XY direction in a noncontact manner. SOLUTION: Four corners of an upper plate 11a on which a specimen is mounted and a lower plate 11b are combined by struts 11c, and an XY stage 11 is constituted. On the upper surface of the upper plate 11a, e.g. a semiconductor wafer 12 is mounted. Electromagnets 14 for levitation are arranged on four corners of the lower surface of a fixed pedestal 13. Magnetic pole surfaces of the electromagnets face the lower plate 11b of the stage 11 and levitate and retain the stage 11 in a noncontact manner. A stator 15a of a linear motor is installed in the upper surface of the fixed pedestal 13, and a movable member for the linear motor is installed on the lower surface of the upper plate 11a of the stage 11. The movable member is constituted of a magnetic material having an uneven surface. The linear motor stator 15a of the fixed pedestal 13 exerts magnetic attractive force to a magnetic pole having the uneven surface in the X, Y directions, so that the stage 11 is moved and positioned.</p> |
