摘要 |
This invention is directed to electromagnetic alignment apparatus, which is particularly adapted, among many other possible uses, for use in aligning the wafers in a microlithography system, said apparatus comprising in combination three or more spaced magnets, three or more coil assemblies mounted to pass through the magnetic fields of the magnets respectively, means for controlling the flow of current through the coil assemblies respectively, said coil assemblies being joined together to form a structure movable with respect to the magnets and adapted to carry an object thereon, the coil assemblies being wound with respect to each other so that by controlling the supply of current to the coils the structure can be moved selectively in three degrees of freedom. |