NUMERICAL MODELING OF ELECTRON AND ION OPTICS ON PERSONAL COMPUTERS

Dramatic advances in the power and cheapness of personal computers (PCs) over the past decade, combined with the development of new computer-aided design software, now enable most aspects of electron and ion optical system design to be carried out on PCs. The latest desktop computers, such as the new 80486-based systems and the IBM RISC System/6000, offer computing speeds faster than many mainframes, and enable complete electron optical systems to be designed quickly and cheaply before they are built. The paper describes and illustrates major areas of electron optical design which can now be routinely computed on PCs, including design of individual electron lenses and deflectors, optimization of complete electron or ion optical columns for lithography and inspection (including dynamic focusing and stigmation), discrete Coulomb interactions, analysis of electron guns, multipole systems for beam transport and aberration correction, tolerancing of individual components and complete electron optical columns, design of photomultiplier tubes, fully three-dimensional (3D) field computation and ray tracing in systems with combined electrostatic and magnetic fields, and the 3D modeling of electron-specimen interactions and charging problems in the scanning electron microscope.