Patent ID: 9607802
Date: 2017-03-28
CPC Classifications: H01J

Claim:
1. An apparatus for aberration correction in electron-optics of an electron beam system, the apparatus comprising: an inner electrode surrounding an opening in the electron-optics, the inner electrode having a continuous annular planar surface extending unbroken from a circular inner perimeter to a circular outer perimeter in a plane of the opening; at least one outer electrode around the inner electrode, the at least one outer electrode having a planar surface in the plane of the opening; circuitry configured to apply an inner voltage level to the inner electrode and at least one outer voltage level to the at least one outer electrode; and a blanker array within the opening which receives an incident electron beam and generates multiple beamlets of electrons, wherein the inner voltage level and the at least one outer voltage levels, as applied to said electrodes, each causes an electric field that influences both electrons of the incident electron beam that are incident to the opening and the multiple beamlets of electrons outgoing from the opening.