Abstract: A spectroscopic scatterometer detects both zero order and higher order radiation diffracted from an illuminated spot on a target grating. The apparatus forms and detects a spectrum of zero order (reflected) radiation, and separately forms and detects a spectrum of the higher order diffracted radiation. Each spectrum is formed using a symmetrical phase grating, so as to form and detect a symmetrical pair of spectra. The pair of spectra can be averaged to obtain a single spectrum with reduced focus sensitivity. Comparing the two spectra can yield information for improving height measurements in a subsequent lithographic step. The target grating is oriented obliquely so that the zero order and higher order radiation emanate from the spot in different planes. Two scatterometers can operate simultaneously, illuminating the target from different oblique directions. A radial transmission filter reduces sidelobes in the spot and reduces product crosstalk.

Abstract: One embodiment of a method for process window optimized optical proximity correction includes applying optical proximity corrections to a design layout, simulating a lithography process using the post-OPC layout and models of the lithography process at a plurality of process conditions to produce a plurality of simulated resist images. A weighted average error in the critical dimension or other contour metric for each edge segment of each feature in the design layout is determined, wherein the weighted average error is an offset between the contour metric at each process condition and the contour metric at nominal condition averaged over the plurality of process conditions. A retarget value for the contour metric for each edge segment is determined using the weighted average error and applied to the design layout prior to applying further optical proximity corrections.

Abstract: A substrate handler for transferring substrates to be exposed from a track to a lithographic apparatus. The substrate handler comprises a controller. The controller is configured to determine an instance for starting a transfer process of a first one of the substrates. The instance is based on a predetermined processing characteristic of the lithographic apparatus, in order to maintain a transfer period of the substrate in the substrate handler substantially constant.

Abstract: A lithography apparatus includes a projection system configured to project a radiation beam onto a substrate, a detector configured to inspect the substrate, and a substrate table configured to support the substrate and move the substrate relative to the projection system and the detector. The detector is arranged to inspect a portion of the substrate while the substrate is moved and before the portion is exposed to the radiation beam.

Abstract: The invention is directed to a method for at least partially removing a contamination layer (15) from an optical surface (14a) of an EUV-reflective optical element (14) by bringing a cleaning gas into contact with the contamination layer. In the method, a jet (20) of cleaning gas is directed to the contamination layer (15) for removing material from the contamination layer (15). The contamination layer (15) is monitored for generating a signal indicative of the thickness of the contamination layer (15) and the jet (20) of cleaning gas is controlled by moving the jet (20) of cleaning gas relative to the optical surface (14a) using this signal as a feedback signal. A cleaning arrangement (19 to 24) for carrying out the method is also disclosed. The invention also relates to a method for generating a jet (20) of cleaning gas and to a corresponding cleaning gas generation arrangement.

Abstract: A lithographic apparatus includes an illumination system, a support, a patterning device, a substrate table, a projection system, and a detector. The apparatus further includes a polarization changing element, such as a quarter-wave plate, that is adjustable and a polarization analyzer, such as a linear polarizer. The polarization changing element and the polarization analyzer are arranged in order in the radiation beam path at the level at which a patterning device would be held by the support. By taking intensity measurements for different rotational orientations of the polarization changing element, information on the state of polarization of the radiation at the level of the patterning device can be obtained. Because the polarization analyzer is located before the projection system, the measurements are not affected by the fact that the detector is located after the projection system, such as at the level of the substrate.

Abstract: Disclosed is a lithographic apparatus comprising a member susceptible to deformation and a deformation sensor for measuring a deformation of said member. The deformation sensor comprises a first birefringence sensing element arranged to be subjected to stress in dependency of the deformation of said member and a light system configured to transmit polarized light through the first birefringence sensing element, wherein said polarized light has a first polarization state prior to being transmitted through the first birefringence sensing element. The deformation sensor further comprises a detector for detecting a second polarization state of the polarized light after being transmitted through the first birefringence sensing element and a calculation unit to determine the deformation of said member based on the first and second polarization state.

Abstract: A displacement measurement system comprising at least one retro reflector and a diffraction grating. Said displacement measurement system is constructed and arranged to measure a displacement by providing a first beam of radiation to the measurement system, wherein the diffraction grating is arranged to diffract the first beam of radiation a first time to form diffracted beams. The at least one retro reflector is arranged to subsequently redirect the diffracted beams to diffract a second time on the diffraction grating. The at least one retro reflector is arranged to redirect the diffraction beams to diffract at least a third time on the diffraction grating before the diffracted beams are being recombined to form a second beam. And the displacement system is provided with a sensor configured to receive the second beam and determine the displacement from an intensity of the second beam.

Abstract: A movable stage system is configured to support an object. The stage system comprises an object table configured to support the object and an object table support defining an object table support surface configured to support the object table. The object table support comprises at least one first actuator to drive the object table support in a first driving direction substantially parallel to the object table support surface. In a projection on a plane parallel to the object table support surface the at least one actuator is spaced with respect to the object table in a direction perpendicular to the first driving direction such that the risk on slip between the object table support and the object table supported thereon is decreased.

Abstract: Systems and methods provide the use of a two or three plate Alvarez lens located in a field plane of a projection lens of a lithographic apparatus. The Alvarez lens can be used to modify the shape of the focal plane to match a previously determined surface topography, while at the same time the Alvarez lens can be designed to include a built-in correction for astigmatism and other residual Zernike errors that would otherwise be introduced.

Abstract: A support for an object, e.g., a semiconductor substrate, includes a main body having a surface configured and arranged to have a plurality of projections. Each of the projections has an associated electrostatic actuator for displacing a free end of the associated projection relative to the main body at least in a direction in a plane parallel to a main surface of the object.

Abstract: Systems, methods, and apparatus are provided for determining overlay of a pattern on a substrate with a mask pattern defined in a resist layer on top of the pattern on the substrate. A first grating is provided under a second grating, each having substantially identical pitch to the other, together forming a composite grating. A first illumination beam is provided under an angle of incidence along a first horizontal direction. The intensity of a diffracted beam from the composite grating is measured. A second illumination beam is provided under the angle of incidence along a second horizontal direction. The second horizontal direction is opposite to the first horizontal direction. The intensity of the diffracted beam from the composite grating is measured. The difference between the diffracted beam from the first illumination beam and the diffracted beam from the second illumination beam, linearly scaled, results in the overlay error.

Abstract: An optical arrangement, e.g. a projection exposure apparatus (1) for EUV lithography, includes: a housing (2) enclosing an interior space (15); at least one, preferably reflective optical element (4-10, 12, 14.1-14.6) arranged in the housing (2); at least one vacuum generating unit (3) for the interior space (15) of the housing (2); and at least one vacuum housing (18, 18.1-18.10) arranged in the interior space (15) and enclosing at least the optical surface (17, 17.1, 17.2) of the optical element (4-10, 12, 14.1-14.5). A contamination reduction unit is associated with the vacuum housing (18.1-18.10) and reduces the partial pressure of contaminating substances, in particular of water and/or hydrocarbons, at least in close proximity to the optical surface (17, 17.1, 17.2) in relation to the partial pressure of the contaminating substances in the interior space (15).

Abstract: Disclosed is a device manufacturing method, and accompanying inspection and lithographic apparatuses. The method comprises measuring on the substrate a property such as asymmetry of a first overlay marker and measuring on the substrate a property such as asymmetry of an alignment marker. In both cases the asymmetry is determined. The position of the alignment marker on the substrate is then determined using an alignment system and the asymmetry information of the alignment marker and the substrate aligned using this measured position. A second overlay marker is then printed on the substrate; and a lateral overlay measured on the substrate of the second overlay marker with respect to the first overlay marker using the determined asymmetry information of the first overlay marker.

Abstract: A projection lens of an EUV-lithographic projection exposure system with at least two reflective optical elements each comprising a body and a reflective surface for projecting an object field on a reticle onto an image field on a substrate if the projection lens is exposed with an exposure power of EUV light, wherein the bodies of at least two reflective optical elements comprise a material with a temperature dependent coefficient of thermal expansion which is zero at respective zero cross temperatures, and wherein the absolute value of the difference between the zero cross temperatures is more than 6K.

Abstract: An inspection method, and corresponding apparatus, enables classification of pupil images according to a process variable. The method comprises acquiring diffraction pupil images of a plurality of structures formed on a substrate during a lithographic process. A process variable of the lithographic process varies between formation of the structures, the variation of the process variable resulting in a variation in the diffraction pupil images. The method further comprises determining at least one discriminant function for the diffraction pupil images, the discriminant function being able to classify the pupil images in terms of the process variable.

Abstract: The invention provides a level sensor configured to determine a height level of a surface of a substrate, comprising a detection unit arranged to receive a measurement beam after reflection on the substrate, wherein the detection unit comprises an array of detection elements, wherein each detection element is arranged to receive a part of the measurement beam reflected on a measurement subarea of the measurement area, and is configured to provide a measurement signal based on the part of the measurement beam received by the respective detection element, and wherein the processing unit is configured to calculate, in dependence of a selected resolution at the measurement subarea, a height level of the measurement subarea, or to calculate a height level of a combination of multiple measurement subareas.

Abstract: Described herein is a method of processing a pattern layout for a lithographic process, the method comprising: identifying a feature from a plurality of features of the layout, the feature violating a pattern layout requirement; and reconfiguring the feature, wherein the reconfigured feature still violates the pattern layout requirement, the reconfiguring including evaluating a cost function that measures a lithographic metric affected by a change to the feature and a parameter characteristic of relaxation of the pattern layout requirement.

Abstract: An approach is used to estimate and correct the overlay variation as function of offset for each measurement. A target formed on a substrate includes periodic gratings. The substrate is illuminated with a circular spot on the substrate with a size larger than each grating. Radiation scattered by each grating is detected in a dark-field scatterometer to obtain measurement signals. The measurement signals are used to calculate overlay. The dependence (slope) of the overlay as a function of position in the illumination spot is determined. An estimated value of the overlay at a nominal position such as the illumination spot's center can be calculated, correcting for variation in the overlay as a function of the target's position in the illumination spot. This compensates for the effect of the position error in the wafer stage movement, and the resulting non-centered position of the target in the illumination spot.

Abstract: The method of the invention tracks how the collective movement of edge segments in a mask layout alters the resist image values at control points in the layout and simultaneously determines a correction amount for each edge segment in the layout. A multisolver matrix that represents the collective effect of movements of each edge segment in the mask layout is used to simultaneously determine the correction amount for each edge segment in the mask layout.