Electron beam exposure system having the capability of checking the pattern of an electron mask used for shaping an electron beam

An electron beam exposure system for writing a pattern on an object, said electron beam exposure system having a capability of checking the pattern to be written on the object, comprising;

• electron beam source means for producing an electron beam such that the electron beam ravels along an optical axis that extends from the electron beam source means to the object;
• beam shaping means provided on the optical axis of the electron beam for shaping the electron beam such that the electron beam has a desired cross section, said beam shaping means having at least one selectable aperture pattern for passing the electron beam thee-through and thereby shaping same;
• focusing means, provided along the optical axis between the beam shaping means and the object, selectively operable for focusing the electron beam, as shaped by as elected aperture pattern of the beam shaping means, on the object and such that an imaged of the selected aperture pattern of the beam shaping means, through which the electron beam has passed, is written on the object;
• a screen, provided along the optical axis between the beam shaping means and the object, having an upper major surfaces for interrupting the electron beam when the electron beam is offset from the optical axis and further having a through-hole in alignment with the optical axis for passing the electron beam therethrough;
• control means for controlling the focusing means, selectively, to project an image of a selected aperture pattern of the beam shaping means, through which the electron beam has passed, onto the upper major surface of said screen when checking the selected aperture pattern of the beam shaping means;
• and
• detection means for detecting the image of the selected aperture pattern that a is projected on the screen.