Abstract: The present invention is directed to a method for selectively scaling the dimensions of a field emission electron gun. The electron gun includes a field emission tip followed by a dual electrode immersion lens. The lens consists of two planar electrodes separated by a dielectric layer. A well defined circular hole is present at the center of each electrode and the dielectric layer. A high scaling factor is applied to the region consisting of the first electrode and the emission tip, reducing the first electrode thickness and bore diameter and the distance between the tip and first electrode to the micrometer range. A weaker scaling factor is applied to the bore diameter of the second electrode and the spacing between the electrodes such that the second electrode bore diameter and distance between the electrodes are approximately equal and are greater than the first electrode thickness and bore diameter and the distance between the tip and first electrode.

Abstract: A proximity effect correction method for electron beam lithography suitable for high voltages and/or very dense patterns applies both backscatter and forward scatter dose corrections. Backscatter dose corrections are determined by computing two matrices, a "Proximity Matrix" P and a "Fractional Density Matrix" F. The Proximity Matrix P is computed using known algorithms. The elements of the Fractional Density Matrix are the fractional shape coverage in a mesh of square cells which is superimposed on a pattern of interest. Then, a Dose Correction Matrix D is computed by convolving the P and F matrices. The final backscatter dose corrections are assigned to each shape either as area-weighted averages of the D matrix elements for all cells spanned by the shape, or by polynomial or other interpolation of the dose correction field defined by the D matrix. The D matrix also provides a basis for automatic shape fracturing for optimal proximity correction.

Abstract: The electron potential of an electron beam is switched between different values without moving the focal plane by effectively changing the axial position of the electron source at the same time that the electron potential is changed. The effective change in axial position of the electron source exactly compensates for the altered effectiveness which magnetic lenses have upon an electron beam of altered electron potential such that the final focal plane remains at the same position without adjusting the field strength of any magnetic lens.