A method of determining a mark measurement sequence for an object comprising a plurality of marks, the method including: receiving location data for the plurality of marks that are to be measured; obtaining a boundary model of a positioning device used for performing the mark measurement sequence; and determining the mark measurement sequence based on the location data and the boundary model.

A method of determining contamination of an optical sensor in a lithographic apparatus, the method including projecting patterned reflected EUV radiation towards the optical sensor and thereby forming an aerial image of a pattern, moving the optical sensor relative to the patterned reflected EUV radiation such that an intensity of EUV radiation measured by the optical sensor varies as a function of the position of the optical sensor, wherein the intensity measured by the optical sensor passes through a minimum, and using the measured intensity to measure contamination of the optical sensor.

An object handling apparatus for handling a generally planar object, the object handling apparatus including: two support arms, at least one of the two support arms movable relative to another support arm generally in a plane such that the two support arms are operable to grip and hold an object disposed in the plane, wherein each of the support arms includes at least one support pad and at least one aligner, the support pads configured to locally contact a surface of the object and apply a force thereto generally perpendicular to the plane so as to support the object and the at least one aligner configured to locally contact a surface of the object and apply a force thereto generally in the plane so as to grip the object.

In a holding apparatus, a first holding unit has a first surface at a position facing a lens barrel, the first surface being inclined with respect to an optical axis of a first optical element, a second holding unit has a second surface at a position facing the lens barrel, the second surface being inclined with respect to an optical axis of a second optical element, and the lens barrel includes a first through-hole that is provided at a position corresponding to the first surface and extends in a first direction orthogonal to the optical axis of the first optical element, and a second through-hole that is provided at a position corresponding to the second surface and extends in a second direction orthogonal to the optical axis of the second optical element.

A novel approach for an alignment system by using glass plates to create off-axis illumination beams is described. A pair of glass plates is inserted into an alignment system to create a pair of off-axis illumination beams. The off-axis illumination beams pass through an aperture stop. A transmissive optic with a plurality of fully reflective mirrors reflects the beams toward the objective. Thereafter, the objective focuses the beams onto the alignment mark on the substrate. The diffracted beam is then detected and analyzed to determine alignment of the substrate. The compact nature of the glass plate alignment system significantly reduces the optical system footprint.

Systems and methods disclosed herein relate to a digital lithography system and method for alignment resolution with the digital lithography system. The digital lithography system includes a metrology system configured to improve overlay alignment for different layers of the lithography process. The metrology system allows for decreased size of alignment marks. Based on determining the positions of alignment marks with the metrology system, correction data is obtained to achieve accurate overlay of layers on subsequent patterning processes.