Accuracy Issues in Chemical and Dimensional Metrology in the SEM and TEM

Published

October 16, 2008

Author(s)

J H. Scott

Abstract

In this work computer simulations are used to understand systematic errors and accuracy concerns in both dimensional and chemical metrology in the scanning electron microscope (SEM) and transmission electron microscope (TEM).Multislice high-resolution TEM (HRTEM) simulations are used to produce synthetic cross-section micrographs of SiO2 gate dielectrics on Si substrates. These synthetic images are processed in the same manner as experimental images to extract a film thickness value from the micrographs. The absolute error in the dielectric film thickness measurement is determined by comparing this measured value with the known, true thickness intrinsic to the sample s structural model used for simulation. This process allows the accuracy of the measurement process to be assessed for a given set of microscope, sample, environmental, data capture, and data processing parameters. Statistical design of experiment methods are used to screen the influence of variables including beam tilt, along-beam thickness, dielectric thickness, defocus, astigmatism, and vibration on the accuracy. The most important main effects are beam tilt, defocus, and vibration, and the most significant two-term interactions are (beam tilt-defocus) and (defocus-vibration). Three dimensional Monte Carlo simulations in Java and Jython are used to simulate the electron transport and x-ray generation of energy-dispersive x-ray (XEDS) experiments in the SEM. This code permits the simulation of synthetic hyperspectral XEDS datasets from complex, chemically heterogeneous nanostructures. Analysis of these datasets reveals the effects of self-absorption, thickness, and beam broadening due to multiple scattering on the accuracy of chemical measurements i

Citation

Measurement Science & Technology

Pub Type

Journals

Keywords

design of experiment, hyperspectral, Monte Carlo, multislice, multivariate statistics

Citation

Scott, J. (2008), Accuracy Issues in Chemical and Dimensional Metrology in the SEM and TEM, Measurement Science & Technology (Accessed May 12, 2024)