Method for correcting an error of the imaging system of a coordinate measuring machine

A method for correcting an error of an imaging system of a coordinate measuring machine, the imaging system including measurement optics and a camera that includes a CCD-chip, the method comprising the steps of:

• measuring a position of at least one edge of at least one structure on a substrate with the imaging system, wherein the substrate is positioned in a first orientation in the coordinate measuring machine, and the position of the at least one edge is determined within a measurement window defined on the CCD-chip of the camera;
• rotating the substrate to set a second orientation of the substrate differing from the first orientation by 180° so that the at least one structure to be measured is arranged in the same way with respect to an optical axis of the measurement optics;
• shifting the measurement window defined on the CCD-chip of the camera such that, for the second orientation, the measurement window is located at the same location on the structure to be measured as in the first orientation;
• measuring a further position of the at least one edge of the at least one structure on the substrate in the second orientation with the imaging system, wherein the at least one edge of the structure is after the rotating step at the same location within the measurement window as prior to the rotating step;
• and
• eliminating a systematic error of the imaging system of the measurement optics of the coordinate measuring machine based on a difference between the measurement at the first orientation and the measurement at the second orientation.