Calibration of a scanning electron microscope

摘要

A scanning electron microscope (SEM) is calibrated for the effects of local charging on a measured critical dimension (CD) of a wafer by first calibrating the microscope with respect to a calibration wafer with a known CD. Local charging on a wafer may be measured as a local landing energy (LLE) so that a scale factor based on a ratio of LLEs for the measurement wafer and a calibration wafer is used to correct a measured CD for the measurement wafer.