Method and system for determining a positioning error of an electron beam of a scanning electron microscope

摘要

A substrate having at least four reference patterns at respective nominal positions on a surface is provided. Using a scanning electron microscope and positioning the wafer stage at respective nominal positions of each reference pattern, each reference pattern is scanned. After determining at least a first and a second intensity profile for each pattern, a reference position offset from each nominal position is calculated. The reference position offsets are used to determine a positioning error of the scanning electron microscope.