Lithographic apparatus configured to reconstruct an aerial pattern and to compare the reconstructed aerial pattern with an aerial pattern detected by an image sensor

摘要

The invention relates to an image for detection of an aerial pattern comprising spatial differences in radiation intensity in a cross section of a beam of radiation in a lithographic apparatus for exposing a substrate. The image sensor comprises a lens (5) arranged to form a detection image of the aerial pattern and an image detector (6) arranged to measure radiation intensities in a plurality, of positions in the detection image.

主权项

1. A lithographic apparatus for exposing a substrate to a beam of radiation, comprising:
a patterning device for forming an aerial pattern in the beam of radiation and including an object mark having comparable dimensions to critical dimension features of a circuit pattern, the aerial pattern comprising spatial differences in radiation intensity in a cross section of the beam of radiation; a projection system configured to project the aerial pattern onto the substrate; a substrate table comprising an image sensor for detection of the aerial pattern, the image sensor comprising:
a lens configured to form a detection image of the aerial pattern; andan image detector configured to measure radiation intensities in a plurality of positions in the detection image; an aberration sensor configured to measure aberrations of the projection system, wherein the aberration sensor is configured to determine an aberration footprint per field point of the projection system; a control unit configured to model a reconstructed aerial pattern using information of the patterning device and the measured aberrations of the projection system, to compare the modeled reconstructed aerial pattern with the aerial pattern detected by the image sensor, and to calculate adjustment data based on the comparison of the modeled reconstructed aerial pattern and the aerial pattern detected by the image sensor; and a parameter adjustment device configured to control at least one parameter of the lithographic apparatus based on the adjustment data such that a difference between the modeled reconstructed aerial pattern and the aerial pattern detected by the image sensor is minimized.