Lithographic apparatus and device manufacturing method utilizing data filtering

A method, comprising:

• projecting a beam of radiation onto a substrate as an array of sub-beams of radiation;
• modulating the sub-beams of radiation to substantially form a requested dose pattern on the substrate, the requested dose pattern being built up over time from an array of spot exposures, each of the spot exposures being produced by one of the sub-beams of radiation at a given time;
• converting data defining the requested dose pattern to a sequence of data representing the requested dose at a corresponding sequence of points within the pattern;
• generating a control signal from the sequence of data that is used to control the modulating;
• measuring the position of at least a portion of the substrate relative to a plane of best focus;
• and
• modifying the control signal based on measured deviations of the position of at least a portion of the substrate relative to the plane of best focus.

A lithography apparatus, comprising:

• a patterning device configured to modulate a beam of radiation as an array of sub-beams of radiation, the sub-beams of radiation substantially forming a requested dose pattern on a substrate;
• a projection system configured to project the modulated sub-beams of radiation onto the substrate;
• a focus determination unit configured to measure a position of at least a portion of the substrate relative to a plane of best focus and output a coarse adjustment signal and focus data;
• a controller configured to receive the coarse adjustment signal and perform a coarse adjustment to a position of the projection system and a position of a substrate table based on the coarse adjustment signal;
• a rasterizer configured to convert data defining the requested dose pattern to a sequence of data representing the requested dose at a corresponding sequence of points within the pattern;
• a data path control device configured to:
• receive the sequence of data and generate a control signal therefrom, the control signal being used to control the patterning device;
• and
• receive the focus data and generate a fine adjustment signal, the fine adjustment signal configured to change the control signal based on measured deviations of the position of at least a portion of the substrate relative to the plane of best focus.