Chapter 2 - Synthesis of Scanning Electron Microscopy Images of Nanostructures by High-Performance Monte Carlo Modeling

Abstract

Some of the main issues in Monte Carlo modeling of Critical Dimension Scanning Electron Microscopy are the assessment of the physical limits of the technique for nanostructures, and the extraction of critical dimensions from arbitrary photoresist structures. In addition, other issues include the estimation of line edge roughness parameters, the quantification of the impact of proximity and self-charging effects, as well as the implementation of energy-spectrum analysis capabilities. All these challenges require increased accuracy in the description of the three-dimensional model geometry, as well as consistent definition of the local electromagnetic fields at nanometer scale. A solution to these problems is presented, which is based on original Monte Carlo code by the ETH Zurich, that includes an editor for arbitrary three-dimensional geometries with subnanometer resolution, and high-performance parallel computing capabilities. Others include calculation of the trapped charge and related electric field inside and outside the sample, as well as electron tracking in the electrostatic field. These functionalities are efficiently implemented by coupling the Monte Carlo simulator to a technology computer-aided design environment.