E-beam simulation for advanced SEM applications in semiconductor industry

Scanning Electron Microscopy (SEM) technology makes use of an electron beam (e-beam) with wide energy range from 0.1 to 50 keV, so it is possible to measure wafers from surface to deep and buried structures. Due to its superior accuracy, it is widely used for in-line metrology and inspection (MI) process. As devices scaling down for performance enhancement, the MI process became inaccurate due to the target structure shrinkage and complicated electrons' behavior inside it. To overcome the challenges, accurate simulation tool is required to understand its underlying mechanism theoretically. In this paper, we propose a unifying framework for simulating SEM operation by implementing Nebula e-beam computing algorithm on the Technology Computer-Aided Design (TCAD) environment. The proposed framework integrates various physics models including the scattering and transport behaviors of electrons, which enables to calculate the important trajectories of electrons in the most important regions of wafers. In addition, it gives an expandability on further integration thanks to the computability of TCAD environment. We validate the proposed framework with demonstrating key applications on real products.