Auto calibration method suitable for use in electron beam lithography

摘要

A method of selecting values for parameters in a calibration map used to correct for measurement errors. The locations of points in a grid on an uncalibrated calibration plate are measured for different orientations of the calibration plate. The parameters in the calibration map and the parameters relating the orientations of the calibration plate are determined to minimize the deviation from congruence of the image under the calibration map of the grid in each orientation. The orientations should be related by rigid motions having rotation axes that are separated sufficiently to remove uncertainties in the calibration which arise if the rotation axes are all collinear or nearly collinear.