Electron beam lithography apparatus having electron optics correction system

Abstract

An electron beam apparatus used in a cell projection method has a system for correcting the electron optics. A figured electron beam that has been passed through a cell having a complex figure shape is directed onto a stage on which a substrate is positioned. A fine hole is formed in the substrate and an electron detector is positioned underneath the fine hole to receive the electrons that pass through the fine hole. The output signal of the electron detector is processed to provide a representation of the degree of focus and astigmatism correction of the electron optics. When a line and space pattern is used to shape the electron beam, the output signal from the electron detector has a series of peak intensity values that, when maximized, indicate an optimum correction of the electron optics. Optionally, a limited aperture is positioned between the substrate having a fine hole and the electron detector to limit the detection of scattered electrons that have not passed through the fine hole.

Dependencies are inferred from the claim text.