A method for exposing a wafer according to pattern data using a charged particle lithography machine, compiising providing the pattern data as a dose map in a vector format; rasterizing the pattern data, the rasterizing comprising rendering the vector dose map to generate multi-level gray scale data and dithering the multi-level grayscale pattern data to generate two-level black/white data; supplying the two-level black/white data to the charged particle lithography machine; and switching the beamlets generated by the charged particle lithography machine on the basis of the two-level black/white data. A method for processing pattern data for controlling charged particle beamlets in a charged particle lithography machine, comprising performing flattening preprocessing to transform the pattern layout data into a dose map; rasterizing the dose map, comprising rendering the vector dose map to generate multi-level gray scale data and dithering the multi-level grayscale pattern data to generate beamlet control signals in the form of two-level black/white data; and multiplexing the beamlet control signals. The methods further comprise making corrective adjustments to the vector dose map and/or the multi-level gray scale data and/or the two-level black/white data to correct for variations in beamlet position, size, current, or other characteristics.