METHOD AND APPARATUS FOR DETECTING IN-PLANE POSITION IN A PLANAR STAGE BY MEASURING AIR GAP DISPLACEMENT

摘要

A method and an apparatus for detecting an in-plane position in a planar stage by measuring air gap displacement are provided to reduce a measuring cost by simplifying a structure thereof. An apparatus for detecting an in-plane position in a planar stage includes a base for loading a planar stage, at least one flat plate(102,103,104) to be operated on the base, and at least one sensor(101) for measuring air gaps(105,106,107) between the base and the flat plate. The apparatus further includes algorithm to calculate the displacement of the planar stage by using information about the air gap and a geometric structure of the flat plate. The apparatus further includes a controller to generate a feedback signal corresponding to the displacement.