Abstract: A projection system (PS) is provided which includes, in an embodiment, two frames. The optical elements of the projection system are mounted on a first frame (200). The position of the optical elements is measured relative to a second frame (300) using a first measurement system (910). A second measurement system (920) is used to measure a parameter associated with a deformation of the second frame. The measurement made by the second measurement system can be used to compensate for any errors in the position of the optical elements as measured by the first measurement system resulting from deformations of the second frame. Typically, deformations of the frames are due to resonant oscillation and thermal expansion. Having two frames enables the optical elements of the projection system to be positioned with a high degree of accuracy.

Abstract: An electrostatic clamp for use in a lithographic apparatus includes a layer of material provided with burls, wherein an electrode surrounded by an insulator and or a dielectric material is provided in between the burls. The electrostatic clamp may be used to clamp an object to an object support in a lithographic apparatus.

Abstract: A system and method are used to detect thermal radiation from a mask. Debris particles on the mask heat up, but do not cool down as quickly as the surrounding mask. Due to the temperature difference, the wavelength of radiation emitted by particles and the mask differs. Thus by detecting the thermal radiation, it is possible to detect the presence of particles deposited on the mask. If particles are detected, the mask can be cleaned.

Abstract: A radiation system is configured to generate a radiation beam. The radiation system includes a radiation source configured to generate a plasma that emits radiation and debris, and a radiation collector configured to direct collected radiation to a radiation beam emission aperture. A magnetic field generator is configured to generate a magnetic field with a gradient in magnetic field strength to direct the plasma away from the radiation collector.

Abstract: Data from the piezo-electric sensors in the mounts for the projection system can be used in the control loops for other parts of the lithographic apparatus, for example the mask table, the substrate table or the air mounts for the frame bearing the projection system. Information from, for example, a geophone, which is used to measure the absolute velocity of the frame bearing the projection system, can be used in the control loop for the piezo-electric actuator in the mount for the projection system.

Abstract: Model-Based Sub-Resolution Assist Feature (SRAF) generation process and apparatus are disclosed, in which an SRAF guidance map (SGM) is iteratively optimized to finally output an optimized set of SRAFs as a result of enhanced signal strength obtained by iterations involving SRAF polygons and SGM image. SRAFs generated in a prior round of iteration are incorporated in a mask layout to generate a subsequent set of SRAFs. The iterative process is terminated when a set of SRAF accommodates a desired process window or when a predefined process window criterion is satisfied. Various cost functions, representing various lithographic responses, may be predefined for the optimization process.

Abstract: A lithographic apparatus may include an optical element, such as an immersion fluid reservoir, which supported at least in part by a bearing, such as a gas bearing. To enable illumination by the lithographic apparatus of an edge of the substrate, a surrounding structure is provided that surrounds the substrate. A level parameter of the substrate, such as a thickness of the substrate, is measured by a sensor, such as a thickness sensor. By means of an actuator, the substrate table on which the substrate is or will be held is positioned with respect to the surrounding structure, such that a surface of the substrate would be on a substantially same level as a surface of the surrounding structure, thus enabling the optical element to transition from the surface of the substrate to the surface of the surrounding structure and vice versa.

Abstract: A lithographic apparatus arranged to transfer a pattern from a patterning device onto a substrate is disclosed, the apparatus including a substrate table constructed to hold a substrate, a first clamping system configured to clamp the substrate table to a substrate table support structure, and a second clamping system configured to clamp a substrate to the substrate table after the substrate table has been clamped to the substrate table support structure.

Abstract: A gas bearing has a first bearing part defining a first bearing surface and a second bearing part defining a second bearing surface. Between the first bearing surface and the second bearing surface there is a gap. A gas supply device supplies a gas to the gap. The first bearing part is at least partly ferromagnetic, and the second bearing part has at least one permanent magnet interacting with the first bearing part for pre-tensioning the gas bearing. The gas bearing may be part of a lithographic apparatus.

Abstract: A lithographic apparatus includes a position measurement system to determine along a measurement path a position of a first part of the lithographic apparatus with respect to a position of a second part of the lithographic apparatus. The position determination system comprises a plurality of temperature sensors to measure a temperature of a medium along the measurement path. The position measurement system corrects the determined position making use of the temperature as measured by the temperature sensors.

Abstract: A transmissive spectral purity filter is configured to transmit extreme ultraviolet radiation. The spectral purity filter includes a filter part having a plurality of apertures configured to transmit extreme ultraviolet radiation and to suppress transmission of a second type of radiation. Each aperture has been manufactured by an anisotropic etching process.

Abstract: An imprint lithography apparatus includes an actuator configured to displace an imprint template holder relative to a substrate holder to perform an imprint process. The imprint template holder and/or the substrate holder being supported on a support structure, the support structure being mounted to a vibration isolation system that is mounted to a base of the apparatus. The vibration isolation system is configured to provide a vibration isolation of the support structure relative to the base. A control unit is configured to control the actuator during the imprint process. The control unit is arranged to control an adjustable member of the vibration isolation system to adjust a dynamical characteristic of the vibration isolation system during at least part of the imprint process so as to reduce a displacement of the support structure relative to the base due to a force exerted on the support structure during the imprint process.

Abstract: A lithographic apparatus includes a patterning subsystem for transferring a pattern from a patterning device onto a substrate controlled in accordance with recorded measurements of level variations across a surface of the substrate. A level sensor is provided for projecting a level sensing beam of radiation to reflect from a location on the substrate surface and for detecting the reflected sensing beam to record the surface level at said location. The level sensor incorporates at least one moving optical element to scan the substrate surface by optical movement in at least one dimension to obtain measurements of surface level at different locations without mechanical movement between the level sensor and the substrate. Optical path length equalization measures may be employed, using shaped reflectors and/or additional moving mirrors, to avoid focus variation during the scan.

Abstract: The invention relates to detecting targets located within patterns. The invention operates in the pupil plane by filtering the fourier transform from the surrounding pattern. In particular the method includes performing a fourier transform on reflected radiation data to form fourier transform data; removing portions of the fourier transform data which correspond to the target to form reduced fourier transform data; interpolating the portions of the reduced fourier transform data which were removed, to form product fourier transform data; and subtracting the product fourier transform data from the fourier transform data.

Abstract: A manifold is provided between an outlet of a fluid supply system for an immersion lithographic apparatus and a separator. The manifold is provided with a pressure sensor which passes the measured pressure in the manifold to a mass flow controller. The mass flow controller controls a leak flow into the manifold based on the measured pressure in the manifold so as to maintain a desired pressure in the manifold.

Abstract: A spectral purity filter includes an aperture. The spectral purity filter is configured to enhance the spectral purity of a radiation beam by being configured to absorb radiation of a first wavelength and allow at least a portion of radiation of a second wavelength to transmit through the aperture. The first wavelength is larger than the second wavelength. The spectral purity filter may be used to improve the spectral purity of an Extreme Ultra-Violet (EUV) radiation beam.

Abstract: A immersion lithographic apparatus is disclosed in which one or more liquid diverters are positioned in a space surrounded by a liquid confinement structure. A function of the liquid diverter(s) is to hinder the formation of one or more recirculation zones of immersion liquid which may lead to variations in refractive index of the immersion liquid in the space and thereby imaging errors.

Abstract: Liquid is supplied to a space between the projection system and the substrate by an inlet. In an embodiment, an overflow region removes liquid above a given level. The overflow region may be arranged above the inlet and thus the liquid may be constantly refreshed and the pressure in the liquid may remain substantially constant.

Abstract: An immersion lithographic projection apparatus having a megasonic transducer configured to clean a surface and a method of using megasonic waves to clean a surface of an immersion lithographic projection apparatus are disclosed.

Abstract: When using a scatterometer different portions of a target area may be at different focal depths. When the whole area is measured this results in part of it being out of focus. To compensate for this an array of lenses is placed in the back focal plane of the high numerical aperture lens.