Patent ID: 7499180

Claim:
An alignment stage apparatus having a stage movable along a surface of a surface plate, said stage apparatus comprising: a plane mirror which extends in two directions substantially perpendicular to each other in order to measure a position of the stage in a translation direction and a tilt of the stage in the direction of height; first measurement means for irradiating a laser beam to said plane mirror and measuring the position of the stage in the translation direction by using reflection of the laser beam; second measurement means for irradiating a laser beam to said plane mirror and measuring the position of the stage by using reflection of the laser beam at a position spaced apart from said first measurement means, in the direction of height, in order to measure a tilt of the stage; a plurality of third measurement means for measuring a tilt of the stage in the direction of height by measuring a plurality of positions in the direction of height of the stage, wherein a measurement distance in which said plurality of third measurement means are arranged is larger than a distance between said first measurement means and said second measurement means; arithmetic means for calculating, when said first measurement means, said second measurement means and said plurality of third measurement means perform the measurement while the stage moves in the translation direction, an error of a surface of said plane mirror corresponding to the position of the stage, on the basis of a difference between a first tilt amount and a second tilt amount, wherein the first tilt amount is obtained by calculating a difference between a measurement result measured by said first measurement means and a measurement result measured by said second measurement means, and the second tilt amount is obtained based on measurement results measured by said plurality of third measurement means; and control means for correcting the first tilt amount based on the error calculated by said arithmetic means and controlling a driving of the stage based on the correction result.