Patent ID: 7567699
Filing Date: 2009-07-28
Classification: G01B,G03F,G06T,H01L

Abstract:
1. A method for determining the center of a rotationally symmetrical alignment mark thereby using an image recognition software, comprising the following steps: (a) recognizing the alignment mark (J) by means of the image recognition software and determining the position of a first reference point (R (b) rotating the image (J) of the alignment mark around a symmetry angle with respect to which the alignment mark is rotationally symmetrical; (c) recognizing the rotated image (J′) of the alignment mark by means of the image recognition software and determining the position of a second reference point (R (d) determining the center of rotation of the rotated image (J′) of the alignment mark on the basis of the rotated first reference point (R wherein steps (a)-(d) above are performed by a computer.