Abstract: A substrate table is provided with an optical system that includes a first window and a second window arranged to allow radiation to pass into an optical arm. At least two mirrors are provided within the optical arm and are arranged to reflect radiation that is passed through the windows. At least two lenses are positioned to receive radiation reflected from the mirrors, wherein the first window is provided with a first alignment mark and the at least two mirrors and at least two lenses are arranged to form an image of the first alignment mark at the second window. A second alignment mark is provided in the second window, or in the substrate table at a location adjacent to the second window.

Abstract: A lithographic projection apparatus is provided with an optical system built into the wafer table for producing an image of a wafer mark that is provided on the back side of the wafer. The image is located at the plane of the front side of the wafer and can be viewed by an alignment system from the front side of the wafer. Simultaneous alignment between marks on the back and front of the wafer and a mask can be performed using a pre-existing alignment system.

Abstract: The invention relates to a substrate table arranged to support a substrate provided with at least one substrate mark. The at least one substrate mark having a position that can be measured using an alignment system. The substrate table is provided with an optical system having a magnification factor deviating from 1, for providing an image of the at least one alignment mark to be measured by the alignment system.

Abstract: The invention is directed to enabling substrate identification by comparing the measured distance between two features on an unidentified substrate with one or more stored distances. The one or more stored distances are the distances intended during the design of one or more substrates. The unidentified substrate is identified by a stored distance that corresponds to the measured distance. The two features are selected from a plurality of features that may be placed on a back side or a front side of a substrate. An optical system is provided for reading the features from the back side or a front side of the substrate.

Abstract: A lithographic apparatus has a plurality of patterning arrays (e.g., 2, 4, etc.), which are spaced apart in an object plane. A combined, overlapped image of the patterning arrays is projected onto the substrate. Because the image is formed from radiation produced from spaced apart patterning arrays, the image arrives from different angles and has a higher effective numerical aperture (NA).

Abstract: A calibration method comprising generating a pattern with an array of individually controllable elements, providing a substrate table with a radiation sensor, using radiation to generate an image of the pattern at the substrate table, moving at least one of the generated pattern and the substrate table relative to each other in order to move the image relative to the sensor, detecting radiation intensity with the sensor, and calculating a calibration establishing a relationship between coordinates of the coordinate system of the array of individually controllable elements and coordinates of the coordinate system of the substrate table, based on the detected intensity and the positions of the array of individually controllable elements and the substrate table.

Abstract: In one method of compensating for the distortion of front-to-backside alignment optics, a displacement vector between the estimated position of a substrate mark and the actual position of a substrate mark is calculated. An optical correction array is also calculated by moving a reference substrate by a fixed amount and comparing how far an image of a point on the back side of a reference substrate moves to how far a corresponding point on the front side of the substrate moves. The displacement vector and optical correction array may then be used to accurately calculate the position of further substrates.