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Proceedings Paper

Solution of electron optics problems with space charge in 2D and 3D
Author(s): John A. Rouse; Xieqing Zhu; Eric Munro
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Paper Abstract

Space charge effects are significant in many electron optical components, for example CRTs, LaB6 guns and magnetron injection guns. In such devices, the volume space charge influences the beam current and focusing properties. In systems with smaller beam currents, such as e-beam lithography columns, discrete Coulomb interactions cause defocusing, radial blurring and increased energy spread. Various techniques are described for simulation of systems with space charge, including software for modelling rotationally symmetric electron guns with magnetic fields, using second-order finite element method with iterative solution of Poisson's equation. The software has a novel method for the allocation of space charge which simulates the effect of transverse thermal velocities and ensures an even distribution of the space charge. We present finite difference software for 3D systems with space charge, wherein a specified current is associated with each ray, space charge density is assigned to each grid node on the ray path, and then Poisson's equation is iteratively solved for the self- consistent solution. Discrete Coulomb interactions in lithography columns have been modelled with a many-body Monte-Carlo simulation, and various new software features will be described, including the treatment of cell projection systems, and space charge interaction effects in multiple-beam lithography systems.

Paper Details

Date Published: 25 September 1995
PDF: 12 pages
Proc. SPIE 2522, Electron-Beam Sources and Charged-Particle Optics, (25 September 1995); doi: 10.1117/12.221585
Show Author Affiliations
John A. Rouse, Munro's Electron Beam Software Ltd. (United Kingdom)
Xieqing Zhu, Munro's Electron Beam Software Ltd. (United Kingdom)
Eric Munro, Munro's Electron Beam Software Ltd. (United Kingdom)

Published in SPIE Proceedings Vol. 2522:
Electron-Beam Sources and Charged-Particle Optics
Eric Munro; Henry P. Freund, Editor(s)

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