Patent ID: 7864295
Filing Date: 2011-01-04
Classification: G03F

Abstract:
1. A lithography apparatus, comprising: a projection system configured to project a beam of radiation onto a substrate as an array of sub-beams of radiation; a patterning device configured to modulate the sub-beams of radiation to substantially produce a requested dose pattern on the substrate, the dose pattern being built up from an array of spot exposures in which at least neighboring ones of the spot exposures are imaged incoherently with respect to each other and each of the spot exposures is produced by one of the sub-beams of radiation at a particular time; a data manipulation device configured to produce a control signal comprising spot exposure intensities to be produced by the patterning device based on a direct algebraic least-squares fit of spot exposure intensities to data derived from the requested dose pattern, wherein the least-squares fit is performed by multiplying a pseudo-inverted form of a point-spread function matrix by a column vector representing the pattern data derived from the requested dose pattern, the point-spread function matrix comprising information about a shape and relative position of the point-spread function of each spot to be exposed on the substrate by one of the sub-beams of radiation at a given time; and a low-pass filter configured to remove spatial frequency components of a signal above a selected threshold frequency, incorporated offline into the pseudo-inverted form of the point-spread-function matrix, ready for the least-squares fit, by the following operation: