Patent Number: 
Section: claims

1. A pattern definition device (102) for use in a particle-beam processing apparatus (100), said device being adapted to be irradiated with a beam (lp,bp) of electrically charged particles and allow passage of the beam only through a plurality of apertures, said apertures (21,230) of identical shape defining the shape of beamlets (bm) permeating said apertures, wherein the apertures (21) are arranged within a pattern definition field (pf), wherein with said apertures are associated corresponding blanking openings (220) located such that each of the beamlets (bm) traverses that blanking opening which corresponds to the aperture defining the beamlet respectively, each blanking opening (220) being provided with a deflection means (221) controllable by a blanking signal (911) between two deflection states, namely, a first state (‘switched on’) when the deflection means has assumed a state in which particles radiated through the opening are allowed to travel along a desired path (pl), and a second state (‘switched off’) when the deflection means is deflecting particles radiated through the opening off said path (pl), wherein the positions of the apertures (21) in the pattern definition field (pf) taken with respect to a direction (Y) perpendicular to a scanning direction and/or a direction (X) taken with respect to a direction parallel to said scanning direction are offset to each other by not only multiple integers of the effective width (w) of an aperture taken along said direction, but also additional multiple integers of an integer fraction of said effective width (‘fractional offsets’), said scanning direction (sd) denoting a direction along which an image of the apertures formed by said beam on a target surface is moved over the target surface during an irradiation process. 2. The device of claim 1, comprising an aperture array means (203) for forming a number of beamlets and a blanking means (202) for controlling the passage of selected beamlets, said aperture array means (203) having a plurality of apertures (21,230) of identical shape defining the shape of beamlets (bm) permeating said apertures, wherein the apertures (21) are arranged within a pattern definition field (pf) in which the positions of the apertures (21) taken with respect to a direction (Y) perpendicular to the scanning direction and/or a direction (X) taken with respect to a direction parallel to the scanning direction are offset to each other by not only multiple integers of the effective width of an aperture taken along said direction, but also by additional multiple integers of an integer fraction of said effective width (‘fractional offsets’), and said blanking means (202) having a plurality of blanking openings (220) arranged in an arrangement corresponding to the apertures (230) of the aperture array means (203). 3. The device of claim 1, wherein the fractional offsets are integer multiples of ½N times the effective width of an aperture, where N is a positive integer, preferably greater than 1. 4. The device of claim 1, wherein the pattern definition field (pf) is segmented into several domains (D), each domain being composed of a plurality of staggered lines (pl) of apertures running along the scanning direction, wherein the apertures are spaced apart within said lines by an integer multiple of the effective width (w) of an aperture and are offset between neighboring lines by a fraction (mw) of said integer multiple width,wherein along the direction perpendicular to the scanning direction, the apertures of a domain are offset to each other by multiple integers of the effective width (w) of an aperture, whereas the offsets of apertures of different domains are fractional offsets. 5. The device of claim 4, wherein the domains have arrangements of apertures which are corresponding as regards the relative position of aperture within each domain. 6. The device of claim 5, wherein the domains have the same number of apertures. 7. The device of claim 4, wherein the fractional offsets are integer multiples of ½N times the effective width of an aperture, where N is a positive integer greater than 1, and the number of domains with different fractional offsets is 22N−1. 8. The device of claim 4, wherein the fractional offsets are integer multiples of ½N times the effective width of an aperture, where N is a positive integer greater than 1, and the number of domains with different fractional offsets is 2N, the fractional offsets running along a diagonal of an aperture's base shape. 9. The device of claim 1, wherein the blanking signals are fed to the pattern definition field (pf) partly at a side running parallel to the scanning direction, partly at a side running perpendicular. 10. The device of claim 1, wherein the shape of the apertures is substantially equivalent to a two-dimensional geometrical base shape of a contiguous covering of the plane. 11. The device of claim 10, wherein the base shape is a square. 12. The device of claim 1, comprising blanking openings whose line feeding the respective blanking signal comprises a component which is accessible on a surface of the device by a structural modification and which is adapted to change its transmissivity for the respective blanking signal between a electrical connecting state and a blocking state upon treatment by said structural modification. 13. The device of claim 12, wherein the component is realized as a conductor segment adapted to be irreversibly modified between an electrical well-conducting and a non-conducting state. 14. The device of claim 1, wherein the blanking signals are derived from feeding lines, each feeding line serving blanking signals for a number of blanking openings, which are propagated through a series of shift registers into a sequence of intermediate buffer means, one buffer means for each blanking opening, and the data contained in the buffer means are activated by a common trigger signal. 15. The device of claim 14, wherein the blanking signal for each blanking opening is a multi-bit signal, said signal coding a duration of how long within one exposure time the respective aperture is switched on. 16. The device of claim 1, wherein the deflection means are adapted to deflect, in the switched off state, the particles to an absorbing surface (204) of said exposure apparatus (100) mounted after the device as seen in the direction of the particle beam. 17. The device of claim 10, wherein the shape of the apertures is equivalent to a two-dimensional polygonal base shape of a contiguous covering of the plane, with rounded and/or beveled edges. 18. The device of claim 17, wherein the area of the shape of the apertures is the same as that of the original polygonal base shape. 19. The device of claim 17, wherein the shape of the apertures is a corner-rounded square.