ELECTRON BEAM ALIGNER AND MASK FOR ELECTRON BEAM EXPOSURE

摘要

PROBLEM TO BE SOLVED: To improve the throughput by correcting the aberration which occurs when the electron beam from an arcuate area of an object defined by two circular arcs with center at the optical axis of a microelectronic optical system passes through a projection optical system. SOLUTION: When an electron beam at a wire area is focused on a wafer, the aberration (esp. curvature of field, astigmatism) increases away from the optical axis (esp. raidally outward from the optical axis) of an electron optical system. An electron beam at an arcuate region defined between two circular arcs with center at the optical axis is used therefor to nearly eliminate the curvature of field at an exposed region but leaving an astigmatism which is also nearly eliminated by means for correcting the dispersion or convergence different in the radial and tangential directions of the electron beam in the exposed region, since this beam has focal positions nearly the same in the radial and tangential directions.