Patent ID: 9568907
Date: 2017-02-14
CPC Classifications: G05B,H01J

Claim:
1. Method for computing an exposure pattern for exposing a desired pattern on a target in a charged-particle lithography apparatus, in which a particle beam is directed to and illuminates a pattern definition device comprising an aperture array composed of a plurality of blanking apertures through which said particle beam penetrates for writing said desired pattern by exposing a multitude of pixels within an exposure area on the target, said method taking into account a spatially dependent distortion of the target within the exposure area, with respect to dislocations transversal to the direction of the particle beam, wherein the method comprises: (i) subdividing the exposure area into a plurality of non-overlapping sub-regions, (ii) determining, for each of said subregions, a subregion dislocation, said subregion dislocation comprising a set of parameters describing the distortion of the target at the location of the respective subregion, (iii) providing the desired pattern as a graphical representation on the exposure area on the target, said graphical representation being composed of a plurality of graphical elements, each graphical element located at a respective position in the exposure area, (iv) modifying the graphical representation in accordance with the plurality of subregion dislocations, by dislocating each graphical element according to a subregion dislocation of the subregion which includes the respective position of the graphical element, obtaining a plurality of graphical elements thus dislocated, which compose a corrected graphical representation, (v) calculating, from the corrected graphical representation, an exposure pattern defined on the multitude of pixels, said exposure pattern being suitable to create a nominal dose distribution on the target realizing contour lines representing the desired pattern.