Inspection having a segmented pupil

摘要

A method and an apparatus that may include optics that is arranged to illuminate a surface of a sample with radiation and to collect reflected radiation from the surface of the sample; wherein the optics includes a pupil that has multiple pupil segments that correspond to different angular regions of collection or illumination; and a detection module arranged to receive the reflected radiation and generate, for each pupil segment, pupil segment detection signals.

主权项

1. An apparatus comprising:
optics arranged to illuminate a surface of a sample and to collect radiation from the surface of the sample, the optics comprising:
a pupil having multiple pupil segments that correspond to different angular regions of collection or illumination; andoptical components configured to direct radiation from or to different pupil segments to different directions; a detection module arranged to receive the radiation from or to the different pupil segments and generate an image of the sample for each corresponding pupil segment; and an image processor arranged to:
obtain a difference image by subtracting a first image corresponding to a first pupil segment from a second image corresponding to a second pupil segment to provide gradient of phase information associated with the surface of the sample; andintegrate the difference image to provide a phase map of the surface of the sample.