Patent ID: 7777201

Claim:
A method for irradiating a target with a beam of energetic electrically charged particles, comprising: providing a pattern definition means having a plurality of apertures transparent to said particles, illuminating said pattern definition means by said beam, which traverses the pattern definition means through said apertures thus forming a patterned beam (pb) having a corresponding plurality of beamlets, forming said patterned beam into an image on the location of the target, said image comprising the images of at least part of the plurality of apertures, said images of apertures having a first width (w), and moving said target relative to the pattern definition means along a path within an image plane in which the images of apertures are formed, wherein during pixel exposure periods the location of said beam image is moved along with the target, the pixel exposure periods having a duration within which the relative movement of the target covers a distance of advance greater than the first width as measured on the target, and after said pixel exposure periods the location of said beam image is changed with respect to the target, said change of location generally compensating the movement of the location of the beam image during the pixel exposure periods with regard to the location of the pattern definition means.