An electron-beam exposure system includes: (1) a stage for supporting a wafer, (2) a planar electron-beam source that emits multiple electron beamlets toward the stage, (3) an electric-field generator for forming an electric field to accelerate the electrons in the electron beamlets, (4) a magnetic-field generator for forming a magnetic flux in the space between the planar electron-beam source and the wafer stage. The magnetic filed generator is structured and arranged such that the magnetic flux formed thereby is (1) substantially evenly distributed within a plane perpendicular to the optical axis, and (2) of increasing flux density, ranging from a first density in the vicinity of the planar electron-beam source, to a second density (greater than the first density) in the vicinity of the wafer stage. The electrons in the electron beamlets follow the lines of magnetic flux such that the beamlet width is decreased at the stage compared to the beamlet width at the planar electron-beam source. The electron beamlets are preferably individually switchable, on and off, by word lines and bit lines on the planar electron-beam source. To form a desired pattern on a wafer surface, the stage is moved through a small area, while the electron beamlets are modulated as needed to write the desired pattern.