| 摘要 |
<p>This invention is directed to electromagnetic alignment devices, which are particularly adapted, among other possible uses, for use in aligning the wafers in a microlithography system, said devices comprising in combination a base plate (12), a first current carrying coil assembly (18) mounted on the base plate (12), a second current carrying coil assembly mounted on the base plate in spaced relationship with respect to the first coil assembly, a first magnet (22) mounted adjacent the first coil assembly and a second magnet mounted adjacent the second coil assembly, an upper connecting piece (38) connecting the first and second magnets, a mount (66) for receiving an object on the upper connecting piece (38), the base plate and magnets and upper connecting piece coacting to form a magnetic circuit, a controller (68) for controlling the flow and direction of current through the coil assemblies to move the magnets and upper connecting piece with respect to the base plate, a plurality of linear actuators (48, 50, 58) mounted between the magnets and the upper connecting piece respectively for moving the connecting piece with respect to the magnets.</p> |
