Pattern generators and microcolumns for ion beam lithography

A self-aligned microfabrication process has been developed for micron-sized extraction systems, which can be used for pattern generators or microcolumns in ion beam lithography. The extraction of ions from a plasma source through micron-sized apertures is shown not to follow traditional design rules, and the governing equations of interest for meeting design parameters are presented. First order focal properties of the pattern generator and microcolumn are described using Davisson and Calbick’s derivation [C. J. Davisson and C. J. Calbick, Phys. Rev. 38, 558 (1931); 42, 580 (1932)] for an aperture lens. A second order refinement of the focal properties is characterized and explained with computer simulations using MEBS©.