Estimation and correction method for the two-dimensional position errors of a planar XY stage based on motion error measurements

Abstract

This paper describes an estimation and correction method for the two-dimensional (2D) position errors of a planar XY stage that is driven along the Y-axis by two linear motors. The 2D position errors of the stage were estimated and corrected based on measured motion errors from a conventional laser interferometer system. To compensate for the planar XY stage 2D position errors, corrections were introduced for the yaw, perpendicular, straightness and 1D position errors along each axis, which are predominantly caused by linear scale, yaw, and pitching motion errors. The effect of the motion error corrections was evaluated by diagonal measurements based on the ISO230-6 standard and six different 1D position error measurements along the X and Y-axes. By applying error motion corrections, the diagonal systematic deviation at the center point was improved from 499.7 mu m to 1.16 mu m, and the estimated maximum 2D position errors were improved to -0.263 and 0.530 mu m in the X and Y directions, respectively. The diagonal systematic deviation at a corner point was 1.23 mu m and the estimated maximum difference between the corner and center points improved from -2.603 and 2.603 mu m to -0.05 and 0.12 mu m in the X and Y directions respectively. (C) 2005 Elsevier Ltd. All rights reserved.