Abstract: A metrology system includes a radiation source, an adjustable diffractive element, an optical system, an optical element, and a processor. The radiation source generates radiation. The adjustable diffractive element diffracts the radiation to generate first and second beams of radiation. The first and second beams have first and second different non-zero diffraction orders, respectively. The optical system directs the first and second beams toward a target structure such that first and second scattered beams of radiation are generated based on the first and second beams, respectively. The metrology system adjusts a phase difference of the first and second scattered beams. The optical element interferes the first and second scattered beams at an imaging detector that generates a detection signal. The processor receives and analyzes the detection signal to determine a property of the target structure based on the adjusted phase difference.

Abstract: A method including: obtaining a first image location for an image feature of a first image of at least part of an object surface, obtaining a second image location for an image feature in a second image of at least part of the object surface, and/or obtaining a value of the displacement between the first and second image locations, the first and second images obtained at different relative positions between an image surface of a detector and the object surface in a direction substantially parallel to the image surface and/or the object surface; and determining, by a computer system, that a physical feature is at an inspection surface or not at the inspection surface, based on an analysis of the second image location and/or the displacement value and on an anticipated image feature location of the image feature in the second image relative to the first image location.

Abstract: A lithographic apparatus includes a clamp (406) configured to receive an object (402). The clamp defines at least one channel (408) configured to pass a fluid at a first fluid temperature. The lithographic apparatus also includes a chuck (404) coupled to the clamp. The chuck (404) defines at least one void (464) configured to thermally insulate the chuck from the clamp.

Abstract: A lithographic apparatus includes a clamp (406) configured to receive an object (402). The clamp defines at least one channel (408) configured to pass a fluid at a first fluid temperature. The lithographic apparatus also includes a chuck (404) coupled to the clamp. The chuck (404) defines at least one void (464) configured to thermally insulate the chuck from the clamp.

Abstract: A lithographic apparatus includes a clamp (406) configured to receive an object (402). The clamp defines at least one channel (408) configured to pass a fluid at a first fluid temperature. The lithographic apparatus also includes a chuck (404) coupled to the clamp. The chuck (404) defines at least one void (464) configured to thermally insulate the chuck from the clamp.