| 摘要 |
A lithographic stage (11) is carried by a platen (13) formed of a plurality of tiles containing a uniformly spaced grid of teeth (17) and having low reluctance and high resistivity. The teeth have been formed by powder metal technology using as powder particles of a ferromagnetic material, the particles being of high resistivity or coated with an insulating material. The space between the teeth is filled with non-magnetic material (18), such as epoxy, and the entire platen finished such that it has a smooth and uniform flat upper surface (16). |
