Mount the calibration standard grid specimen on an SEM stub using SEM-approved conductive cement. Allow the cement to dry.
Use dry, canned air to remove any visible traces of dust on the grid surface.
Mount the stub on the SEM specimen stage. Position the specimen surface perpendicular to the electron beam. Follow the manufacturer's specifications for evacuating the specimen chamber to achieve a satisfactory working vacuum.
Disable all automated corrections for tilting and scan rotation. Any rotations required during calibration must be performed manually.
Select the operating conditions, including the working distance, potential difference and magnification range, for which the magnification calibration is required.
Focus the image of the grid on the SEM monitor, and rotate the specimen into a position where the grid pattern lines are aligned with the X- and Y-axes of the monitor. Adjust the contrast so that the grid lines are clearly defined. Record and print the image, ensuring that the magnification indicator is included in the printout.
Use a micron ruler to measure the pitch distance between adjacent grid lines in the X- and Y-directions on the printout. Repeat this measurement three to five times at various points on the image, and calculate the average spacing between the grid lines.
Calculate the corrected magnification by dividing the average measured line spacing by the standard spacing specification provided by the manufacturer of the calibration grid. Compare the corrected magnification to the magnification indicator appearing on the monitor to determine the error in the magnification indicator.