A comprehensive evaluation method for the effect of multiple environmental disturbance sources on scanning electron microscopy imaging by calculating distance correlation coefficients

Abstract

A scanning electron microscope (SEM), an essential tool for high-resolution imaging at the nanometer scale, frequently suffers from the harmful effects of various environmental disturbance sources, such as magnetic, acoustic, and mechanical vibrations. Because these disturbance sources appear as similar defects on SEM images, identifying the major source is not straightforward but remains crucial for implementing countermeasures. This study presents a comprehensive evaluation method for assessing and analyzing the impact of these environmental disturbance sources on imaging. The method uses multiple sensors around the SEM, measures 10 channel signals in real time, analyzes frequency, and estimates the impact of the disturbance. Together with Fourier transform using Welch’s method, the distance correlation coefficient (DCC) analysis demonstrates the capability of the method to identify the major disturbance sources and assess their influence on SEM images. In particular, the DCC method is effective in determining the major disturbance source even in complex conditions in which multiple disturbance sources have a common frequency component or mixed influence on SEM imaging. This comprehensive approach to evaluating the impact of environmental disturbance on SEM imaging offers significant insights into maximizing SEM performance by mitigating harmful effects from the environment, thereby contributing to the improvement of not only image quality but also measurement accuracy based on SEM.