Herein, a method for determining measurement data of a printed pattern on a substrate is described. The method comprises (i) raw images 402 of a substrate comprising a printed pattern corresponding to a reference pattern 401, (ii) an averaged image 403 of the raw images, and (iii) a synthesis based on the averaged image. It involves obtaining a contour 404 . Further, the composite contour is aligned with respect to the reference contour of the reference pattern and extracted from the raw images based on both the output of the composite contour with which the raw contours 415 are aligned and the die-to-database alignment of the composite contour 419 . do. The method also determines a plurality of pattern measurements 425 based on the raw contours and determines measurement data corresponding to the printed patterns based on the plurality of pattern measurements. The method also determines a plurality of process variations, such as stochastic variation, die-to-die variation, intra-die variation, and total variation.
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