Development and characterization of nano line width based on the fusion of high-resolution transmission electron microscopy and scanning electron microscopy

Abstract

The nano line width is the critical dimension of integrated circuits. With the continuous reduction of key technology nodes, integrated circuits have created higher requirements for line width reference materials and their accurate measurement. We developed 7 nm, 22 nm, and 45 nm line width reference materials based on the multilayer deposition technique. Their line features were characterized according to the proposed fusion method. This method combines the advantages of both high-resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM), not only reducing the influence of boundary effects on the accuracy of line width measurement in SEM, but also disseminating the destructive HRTEM results. Moreover, the measurement results trace to the International System of Units (SI) meter definition using the silicon lattice constant built-in the line width. Experimental results illustrated that the measurement accuracy of the proposed method was improved by 40% compared with SEM alone, which meets the accuracy requirements for line width measurement in integrated circuits.