| 摘要 |
This invention is directed to electromagnetic alignment apparatus, which is particularly adapted, among other possible uses, for use in aligning the wafers in a microlithography system, said apparatus comprising in combination a first magnetic circuit having a plurality of elements including a first magnet; a second magnetic circuit having a plurality of elements including a second magnet; the second magnetic circuit being disposed in spaced relationship with respect to the first magnetic circuit; a movable structural component adapted for mounting an object thereon; one element of each magnetic circuit being fixedly attached to the movable structural component; first and second current carrying coil assemblies mounted in the first magnetic circuit; the second coil assembly being disposed at an angle with respect to the first coil assembly; third and fourth current carrying coil assemblies mounted in the second magnetic circuit; the fourth coil assembly being disposed at an angle with respect to the third coil assembly; and control apparatus for controlling the flow and direction of the current through the coil assemblies, respectively.
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