A new evaluation method for the depth of field in a scanning electron microscope (SEM) images in terms of the quality of an optical image is introduced. The depth of field, in our method, is evaluated by calculating the image resolution along the optical axis defined in terms of the information passing capacity (IPC) of an optical system. The IPC corresponds to the mean information content included in an optical image, i.e., the quality of the image, evaluated based on the theory of Linfoot. The depth of field in a high resolution observation evaluated by our method depends on the accelerating voltage of the primary beam and signal- to-noise ratio of the image. The calculated results has agreed well with experiment.

Date Published: 3 September 1993
PDF: 7 pages
Proc. SPIE 2014, Charged-Particle Optics, (3 September 1993); doi: 10.1117/12.155698

Published in SPIE Proceedings Vol. 2014:
Charged-Particle Optics
William B. Thompson; Mitsugu Sato; Albert V. Crewe, Editor(s)