| 摘要 |
<p>A planar motor (400) provides essentially unlimited range of motion in six degrees of freedom to an associated stage, e.g. for photolithography, in either a moving magnet or a moving coil configuration. Moving magnet configurations eliminate cumbersome cables and hoses, and allow higher speed. The motor incorporates checkerboard magnet arrays (403) and/or planar coil arrangements involving overlapped polygonal coil units. Alternatively, the stage is suspended by permanent magnets or by electromagnetic force generated by the motor, allowing the altitude and the tilt angle of the stage to be controlled by commutation of a motor coil. Selective commutation and energizing of coil units conserve power and reduce heat, thermal expansion, and warpage, which otherwise degrade precision. This planar motor provides a single stage to replace conventional stacked stages, thereby increasing effective stiffness and reducing vibration due to low frequency resonances. Electromagnetic levitation of the stage enhances performance and versatility.</p> |
