Patent ID: 7633069

Claim:
A dual-mode electron beam column for selectably providing a Gaussian beam and a variable shaped beam, comprising an electron source for generating an electron beam, a first aperture for confining the beam, a first lens for focusing the confined beam at a selectable one of two first image planes spaced-apart along the column and respectively for the Gaussian beam mode and the shaped beam mode, a second aperture selectably positionable in the beam path in the first image plane respective to the shaped beam mode for shaping the focused beam, a second lens effective in the shaped beam mode to focus the shaped beam at a second image plane, a selectable third aperture in the second image plane for further confining the confined beam in the Gaussian beam mode or for further shaping the shaped beam in the shaped beam mode and beam redirection means operable in the shaped beam mode to so redirect the beam relative to the second and third apertures as to define a variable shape thereof.