Patent ID: 8258488

Claim:
A device for defining a pattern on a target, for use in a particle-beam exposure apparatus, said device being adapted to be irradiated with a beam of electrically charged particles and allowing passage of the beam only through a plurality of apertures, said device comprising: an aperture array means having an aperture array comprising a plurality of apertures defining a shape and relative position of beamlets permeating said apertures; and a blanking array means for switching off the passage of selected beamlets, said blanking array means having a plurality of corresponding openings, each corresponding opening being located in correspondence with a respective aperture of the aperture array and being provided with a controllable deflection means for deflecting particles radiated through the opening off their path, wherein the apertures are arranged in the aperture array means according to an arrangement of apertures, said arrangement defining a size and position of the apertures, wherein the arrangement is based on a basic arrangement but has deviations from the basic arrangement, said basic arrangement corresponding to at least one non-overlapping area containing apertures of equal size and shape arranged in a regular translational lattice grid, said deviations from the basic arrangement being configured to compensate at least one of inhomogeneities of the current density of the beam across the plurality of apertures and imaging distortions in the particle-beam exposure apparatus, and wherein said deviations correspond to a quasi-continuous function which varies from one aperture to a neighboring aperture by an amount being smaller by at least one order of magnitude than a minimal offset allowed within the regular translational grid, at least one of i) a deviated position of each of the apertures is based on a radial distance from a central portion of the aperture array and ii) a size of each of the apertures is based on a radial distance from a central portion of the aperture array.