Patent ID: 6617585
Filing Date: 2003-09-09
Classification: H01J

Abstract:
A method of optimizing the parameters of a charged particle beam projection system comprising the steps as follows:specifying a lens configuration including a collimator lens, a projector lens, and first order optics and then calculating lens excitations; configuring a lens system including lens field distributions, a beam landing angle, and an axis cross-over of a principal off-axis imaging ray; providing an input of a configuration of deflectors formed surrounding and coaxial with the collimator lens and the projector lens including an axial location of the deflectors, then solving a linear equation set, and thereby providing a curvilinear axis and associated deflection field distributions; then calculating third order aberration coefficients yielding a list of a plurality of aberration coefficients; providing an input of dynamic correctors, then calculating excitations to eliminate quadratic aberrations in deflection, then calculate third and fifth order aberrations, providing image blur and distortion vs. deflection, best focal plane, and depth of focus; then testing to determine whether the current result is better than the previous result; if the current result is better than the previous result then changing the input for the axial location of the deflectors to solve the linear equation set again, and otherwise testing whether the current result is acceptable; if the current result is other than acceptable, then providing a new deflector configuration input to again solve the linear equation set and continuing through the steps thereafter; if the current result is acceptable, then testing whether the deflection current is larger; and if the deflection current is larger, then changing the input for the axial location of the deflectors to solve the linear equation set again, and if otherwise then END the process.