Pitch calibration of standard nanoscale for uncertainty reduction of certified reference materials for SEM image sharpness evaluation and magnification calibration

Scanning electron microscopy (SEM) is widely used to observe and analyze nanostructures on surfaces. To obtain accurate and sharp images by SEM, it is necessary to evaluate the sharpness of SEM images and calibrate the magnification simultaneously. The NMIJ-CRM 5207-a is a certified reference material for image sharpness evaluation and magnification calibration. The certified values of NMIJ-CRM 5207-a are the average pitches in the X- and Y- axes. The major source of uncertainty of the NMIJ-CRM 5207-a is the pitch calibration of the commercially available standard nanoscale. To reduce the uncertainty of the pitch calibration value of the standard nanoscale, the pitch calibration was performed using a metrological atomic force microscope and uncertainty was evaluated in this study.