Electron beam exposure system
AssigneeTokyo Shibaura Denki Kabushiki Kaisha
InventorsMamoru Nakasuji, Hirotsugu Wada
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Abstract
An electron beam exposure system has first and second apertures through which is passed an electron beam emitted from an electron gun. A rectangular image formed by superposition of the images formed by the first and second apertures is projected onto a target plane through a third aperture by condenser lenses and projection lenses. When a crossover of the electron beam drifts in the direction perpendicular to the axis of the lens system, the current of the electron beam projected on the target plate decreases. The electron beam current is detected by a faraday cup, and the locus of the electron beam is corrected by a coil assembly interposed between the second and third apertures so that the faraday cup may detect the maximum beam current.
Claims10
An electron beam exposure system having an electron optical column defining an axis, comprising:
- an electron gun for emitting an electron beam and forming a crossover of the electron beam;
- a first aperture for shaping a sectional shape of the electron beam emitted from said electron gun into a predetermined shape;
- means for converging the electron beam passed through said first aperture to form a crossover image;
- a second aperture to which is projected the electron beam emerging from the crossover image;
- means interposed between said first and second apertures for deflecting the electron beam, said deflecting means having the crossover image and a deflection center in a space defined thereby;
- means for projecting the electron beam passed through said second aperture onto a target plane to form a beam spot of rectangular shape by superposition of images by said first and second apertures;
- means for detecting a fluctuation of at least one of two sides of the beam spot defined by the image of said second aperture in a direction perpendicular to the axis of the electron optical column when said deflecting means deflects the electron beam to change a size of the rectangular beam spot;
- and
- means for driving said converging means according to the detected fluctuation to reduce the fluctuation.
An electron beam exposure system having a electron optical column defining an axis, comprising:
- an electron gun for emitting an electron beam and forming a crossover of the electron beam;
- a first aperture for shaping a sectional shape of the electron beam emitted from said electron gun into a predetermined shape;
- means for converging the electron beam passed through said first aperture to form a crossover image;
- a second aperture to which is projected the electron beam emerging from the crossover image;
- means interposed between said first and second apertures for deflecting the electron beam, said deflecting means having the crossover image and a deflection center in a space defined thereby;
- means for projecting the electron beam passed through said second aperture onto a target plane to form a beam spot of rectangular shape by superposition of images by said first and second apertures;
- means for detecting a fluctuation of at least one of two sides of the beam spot defined by the image of said second aperture in a direction perpendicular to the axis of the electron optical column, when said deflecting means deflects the electron beam to change a size of the rectangular beam spot;
- and
- means for driving said deflecting means according to the detected fluctuation to reduce the fluctuation.
Dependencies are inferred from the claim text.