Abstract: In electron beam apparatus having a souce of electrons and a target area toward which the electrons are directed, electron beam forming means are provided along the path from the source to the target. These forming means include a first beam shaping member having a first spot shaping aperture therein, a second beam shaping member having a second spot shaping aperture therein, and means focusing the image of the first aperture in the plane of the second aperture to thereby form a composite spot shape defined by the image of the first aperture and the second aperture. Further means are provided for focusing the image of the composite spot in the target area.Preferably, the apertures are square shaped. Thus, by varying the position of the superimposed image of the first aperture with respect to the second aperture, a wide variety of rectangular shaped composite spots with different dimensions is obtainable. This permits the exposure of rectilinear patterns, e.g.

Abstract: An electron beam system useful in microfabrication of large scale integrated circuit patterns, particularly those of repetitive nature. The electron beam system includes beam shaping and aperture means disposed between an electron beam source and a target area which permit formation and projection of preselected entire characters or portions thereof into the target area for writing upon a wafer at that location. The pattern cells of such characters may contain as many as 1600 image points which are addressed and projected in parallel, thereby greatly reducing the handling requirements for pattern data as opposed to the techniques utilized in prior art scanning electron beam systems. The system further includes means for correcting for spherical aberration arising in the projection of images comprising a large number of parallel image points.

Abstract: A beam of charged particles has its alignment and brightness alternately controlled in accordance with the current of the beam. The measurements of the current and any corrections for alignment or brightness are made when the beam is not applied to a target.

Abstract: A shielded magnetic lens and deflection yoke structure for an electron beam column which minimizes aberrations in the lens system caused by winding asymmetry in the field coil, as well as aberrations due to eddy currents created within the magnetic circuit of the lens by interaction with the field of the deflection yoke. The shield includes a polepiece structure for the magnetic electron lens generally comprising a hollow cylinder formed of a plurality of precisely machined magnetic discs stacked concentrically with precisely machined nonmagnetic discs in alternating sequence with the lens coil positioned adjacent the periphery of the cylinder and the deflection yoke positioned within the cylinder or proximate to either end thereof. In one preferred embodiment of the invention the magnetic discs are formed of a nonconductive material such as ferrite and the nonmagnetic discs are formed of alumina.