Abstract: A method of determining a structure parameter of a target. Illuminating a first region of the target with a first beam and measuring a diffraction pattern. Shifting the position between the target and the projection system to offset a second region to be illuminated from the first region. Illuminating the second region and measuring a diffraction pattern. Retrieving phase information from the measured first and second diffraction patterns. Modeling the target using an estimated structure parameter to calculate a modeled diffraction pattern and modeled phase information. Determining the structure parameter of the target by comparing the measured diffraction patterns and the retrieved phase to the calculated modeled diffraction intensity pattern and the modeled phase information.

Abstract: A method of determining a structure parameter of a target. Illuminating a first region of the target with a first beam and measuring a diffraction pattern. Shifting the position between the target and the projection system to offset a second region to be illuminated from the first region. Illuminating the second region and measuring a diffraction pattern. Retrieving phase information from the measured first and second diffraction patterns. Modeling the target using an estimated structure parameter to calculate a modeled diffraction pattern and modeled phase information. Determining the structure parameter of the target by comparing the measured diffraction patterns and the retrieved phase to the calculated modeled diffraction intensity pattern and the modeled phase information.