Calibration of a scanning electron microscope in the wide range of magnifications for the microscope operation in the integrated circuit production line

We propose a method of calibration of a scanning electron microscope (SEM) in a wide range of magnifications. We also describe a method of SEM measurements of linear dimensions of relief elements of micro- and nanostructures without performing a special calibration of SEM magnification, which can lie in a wide range. The methods are based on the use of the marker of the SEM as a measure of length. In order to do it, the marker has to be certified in special experiments. We present a method for such certification, based on the use of a test object of trapezoidal profile and large angles of sidewall inclination. We studied the dependence of the marker characteristics on the SEM working distance and the nominal marker size declared by the microscope manufacturer. We determined periodicity of performing marker calibration for the SEM being used. The methods are developed for the calibration of SEMs incorporated into the integrated circuit production line, whose magnification may vary considerably in the course of operation, depending on dimensions to be measured.