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A flexible and efficient approach to E‐beam proximity effect correction—PYRAMID

Electron scattering in the resist causes blurring of the written circuit features in electron‐beam (E‐beam) lithography, which is referred to as the proximity effect. As the feature size in a circuit pattern is continuously reduced in an effort to increase circuit density, the proximity effect has become too prominent to be ignored any more. Without a proper correction of the proximity effect, the pattern density and feature shapes that can be fabricated would be significantly limited especially for nanoscale circuit patterns. A hierarchical approach, named PYRAMID, was proposed in order to develop a flexible and efficient method for proximity effect correction. It distinguishes itself from other methods in that it takes a two‐level approach to exposure estimation and modification of shape and/or dose of circuit features. The hierarchical approach of PYRAMID, which exploits the shape of a typical point spread function (PSF) of the E‐beam lithographic process, attempts to reduce the computational requirement without degrading correction accuracy substantially. Through experiments and simulation, it has been demonstrated that PYRAMID has a potential to be a practical E‐beam proximity effect correction method. Currently, PYRAMID is being extended for grayscale lithography and nonrectangular features. Copyright © 2005 John Wiley & Sons, Ltd.