Tuning Parameters in the Genetic Algorithm Optimization of Electrostatic Electron Lenses

The design of electrostatic electron lenses involves the choice of many geometrical parameters for the lens electrodes as well as the choice of voltages applied to the electrodes. The purpose of the design is to focus the electrons at a specific point and to minimize the aberrations of the lens. In a previous study, genetic algorithm...

Comparison of Different Optimization Techniques in Electron Lens Design

To design electron lens systems, applying a fully automated optimization routine has not yet been feasible, especially for the case where the optimization has many free variables of the lens system, such as all parameters that define the geometry of the lens electrodes and the voltage of each electrode. Hence, the study of the implementation of...

Local versus Global Optimization of Electron Lens System Design

In electron optics, the design of electron lens systems is still a challenge. To optimize such systems, the objective function which should be calculated, depends on the electric potential distribution in the space created by the lenses. To obtain the electric potential, the existing methods are generally based on some mathematical techniques...

Surface effects in simulations of scanning electron microscopy images

We have investigated the contributions of surface effects to Monte Carlo simulations of top-down scanning electron microscopy (SEM) images. The elastic and inelastic scattering mechanisms in typical simulations assume that the electron is deep in the bulk of the material. In this work, we correct the inelastic model for surface effects. We...

Simulation of shotnoise induced side-wall roughness in electron lithography

We have developed a fast three dimensional Monte-Carlo framework for the investigation of shotnoise induced side-wall roughness (SWR) formation. The calculation outline is demonstrated by an example for an exposure of a 100nm thick layer of negative tone resist (NTR) resist on top of an infinitely thick silicon substrate. We use our home...

The effect of sidewall roughness on line edge roughness in top-down scanning electron microscopy images

Mapper: High troughput maskless lithography

MAPPER Lithography is developing a maskless lithography technology. The technology combines massively-parallel electron-beam writing with high speed optical data transport used in the telecommunication industry. The electron optics generates 13,000 electron beams that are focused on the wafer by electrostatic lens arrays which are manufactured...