A method for irradiating a target with a beam of energetic radiation formed by electrically charged particles for writing a desired pattern on said target, comprising the steps of - providing a pattern definition means having a plurality of apertures transparent to said radiation, - illuminating said pattern definition means by means of an illuminating wide beam (lb), which traverses the pattern definition means through said apertures thus forming a patterned beam (pb) consisting of a corresponding plurality of beamlets, - forming said patterned beam into a pattern image (pm) on the location of the target, said pattern image comprising the images of at least part of the plurality of apertures covering a number of pattern pixels (px) on the target, and - generating a relative movement between said target and the pattern definition means producing a stepwise movement of said pattern image on the target along a path over a region where a beam exposure is to be performed, exposing a plurality of pattern pixels (px) in said region, characterized in that the pattern comprises a primary pattern region and a secondary pattern region, the primary pattern region including structure features being written with a predetermined primary feature size whereas the secondary pattern region is composed of structure features capable of being written with a secondary feature size which is larger than the primary feature size by a factor of at least 2, wherein writing structure features of the primary pattern region comprises exposing a plurality of exposure spots which are located on the target at respective grid positions of a first exposure grid (161, 162, 163) in a regular arrangement, and writing structure features in the secondary pattern region comprises exposing a plurality of exposure spots which are located on the target at respective grid positions of a second exposure grid according to a second arrangement which is coarser that the regular arrangement of the first exposure grid, wherein during writing structure features of the primary pattern region, the maximum exposure dose for an exposure spot located within the primary pattern region is greater than a dose value level which causes a positive exposure of the respective exposure spot, by a factor of 1.5 to 3.0, whereas during writing structure features in the secondary pattern region, the maximum exposure dose of an exposure spot located within the secondary pattern region matches the dose value level which causes a positive exposure of the respective exposure spot. - providing a pattern definition means having a plurality of apertures transparent to said radiation, - illuminating said pattern definition means by means of an illuminating wide beam (lb), which traverses the pattern definition means through said apertures thus forming a patterned beam (pb) consisting of a corresponding plurality of beamlets, - forming said patterned beam into a pattern image (pm) on the location of the target, said pattern image comprising the images of at least part of the plurality of apertures covering a number of pattern pixels (px) on the target, and - generating a relative movement between said target and the pattern definition means producing a stepwise movement of said pattern image on the target along a path over a region where a beam exposure is to be performed, exposing a plurality of pattern pixels (px) in said region,