Abstract: A lithographic apparatus for patterning a beam of radiation and projecting it onto a substrate, comprising at least two spectral purity filters configured to reduce the intensity of radiation in the beam of radiation in at least one undesirable range of radiation wavelength, wherein the two spectral purity filters are provided with different radiation filtering structures from each other.

Abstract: The present invention makes the use of measurement of a diffraction spectrum in or near an image plane in order to determine a property of an exposed substrate. In particular, the positive and negative first diffraction orders are separated or diverged, detected and their intensity measured. The intensity of each of the first diffraction orders from the diffraction spectrum are compared to determine overlay (or other properties) of exposed layers on the substrate.

Abstract: In a lithographic projection apparatus, a liquid supply system maintains liquid in a space between a projection system of the lithographic projection apparatus and a substrate. A sensor positioned on a substrate table, which holds the substrate, is configured to be exposed to radiation when immersed in liquid (e.g., under the same conditions as the substrate will be exposed to radiation). By having a surface of an absorption element of the sensor, that is to be in contact with liquid, formed of no more than one metal type, long life of the sensor may be obtained.

Abstract: In the measurement of properties of a wafer substrate, such as Critical Dimension or overlay a sampling plan is produced (2506) defined for measuring a property of a substrate, wherein the sampling plan comprises a plurality of sub-sampling plans. The sampling plan may be constrained to a predetermined fixed number of measurement points and is used (2508) to control an inspection apparatus to perform a plurality of measurements of the property of a plurality of substrates using different sub-sampling plans for respective substrates, optionally, the results are stacked (2510) to at least partially recompose the measurement results according to the sample plan.

Abstract: There is disclosed an exposure apparatus, a device manufacturing method and a method of manufacturing an attenuator. According to an embodiment, the exposure apparatus includes a programmable patterning device configured to provide a plurality of individually controllable radiation beams; a projection system configured to project each of the radiation beams onto a respective location on a target; and an attenuator configured to reduce a standard deviation in maximum radiation flux or background exposure level that can be applied to the target by the radiation beams as a function of position on the target.

Abstract: A method of determining focus of a lithographic apparatus has the following steps. Using the lithographic process to produce first and second structures on the substrate, the first structure has features which have a profile that has an asymmetry that depends on the focus and an exposure perturbation, such as dose or aberration. The second structure has features which have a profile that is differently sensitive to focus than the first structure and which is differently sensitive to exposure perturbation than the first structure. Scatterometer signals are used to determine a focus value used to produce the first structure. This may be done using the second scatterometer signal, and/or recorded exposure perturbation settings used in the lithographic process, to select a calibration curve for use in determining the focus value using the first scatterometer signal or by using a model with parameters related to the first and second scatterometer signals.

Abstract: A system and method are provided for determining deformation of a patterning device and/or shift position of the patterning device relative. The system includes a first sensing sub-system that measures respective positions of a plurality of reference marks on the patterning device, and a second sensing sub-system that measures positions of the edge of the patterning device relative to the support. The system further includes a controller to determine an absolute position of the patterned portion and change in the absolute position based on measured respective positions of marks on the patterning device, determine a change in a relative position of the edge of the patterned device based on the measured edge positions, and estimate a change in a position of the patterning device relative to the support and a change in a pattern distortion of the patterned portion of the patterning device over a time period.

Abstract: A metrology target formed by a lithographic process on a substrate includes a plurality of component gratings. Images of the target are formed using +1 and ?1 orders of radiation diffracted by the component gratings. Regions of interest (ROIs) in the detected image are identified corresponding the component gratings. Intensity values within each ROI are processed and compared between images, to obtain a measurement of asymmetry and hence overlay error. Separation zones are formed between the component gratings and design so as to provide dark regions in the image. In an embodiment, the ROIs are selected with their boundaries falling within the image regions corresponding to the separation zones. By this measure, the asymmetry measurement is made more tolerant of variations in the position of the ROI. The dark regions also assist in recognition of the target in the images.

Abstract: A lithographic apparatus has a support structure configured to support a patterning device, the patterning device serving to pattern a radiation beam according to a desired pattern and having a planar main surface through which the radiation beam passes; an outlet opening configured to direct a flow of a gas onto the patterning device; and an inlet opening configured to extract the gas which has exited the outlet opening, wherein the outlet opening and inlet opening are in a facing surface facing the planar main surface of the patterning device.

Abstract: In laser-produced plasma (LPP) extreme ultraviolet (EUV) systems, pressure waves and other impulsive disturbances originating from plasma bubble emitting EUV light are created which affect flight of incoming droplets. These disturbances slow the migration of subsequent droplets to the plasma bubble. Because the incoming droplets are slowed, the laser beam does not directly hit the droplet at a primary focus point. This causes the resulting level of EUV light generated to be lower than expected and is manifested as a periodic oscillation in the LPP EUV system. An iterative learning controller (ILC) is used to reduce the periodic oscillations when operating the LPP EUV system in a burst mode or a continuous mode. The ILC, on the rising edge of each burst, uses an error signal collected during a completed burst and the input control signal from the completed burst to update the input control signal for a next burst.

Abstract: Embodiments of the present invention describe methods of selecting a subset of test patterns from an initial larger set of test patterns for calibrating a computational lithography model. An example method comprises: generating an information matrix for the initial larger set of test patterns, wherein the terms of the information matrix comprise one or more identified model parameters that represent a lithographic process response; and, executing a selection algorithm using terms of the information matrix to select the subset of test patterns that effectively determines values of the identified model parameters that contribute significantly in the lithographic process response, wherein the subset of test patterns characteristically represents the initial larger set of test patterns. The selection algorithm explores coverage relationships existing in the initial larger set of test patterns.

Abstract: Embodiments of the present invention provide methods for optimizing a lithographic projection apparatus including optimizing projection optics therein. The current embodiments include several flows including optimizing a source, a mask, and the projection optics and various sequential and iterative optimization steps combining any of the projection optics, mask and source. The projection optics is sometimes broadly referred to as “lens”, and therefore the optimization process may be termed source mask lens optimization (SMLO). SMLO may be desirable over existing source mask optimization process (SMO) or other optimization processes that do not include projection optics optimization, partially because including the projection optics in the optimization may lead to a larger process window by introducing a plurality of adjustable characteristics of the projection optics.

Abstract: Energy output from a laser-produced plasma (LPP) extreme ultraviolet light (EUV) system varies based on how well the laser beam is focused on droplets of target material to generate plasma at a primary focal spot. Maintaining droplets at the primary focal spot during burst firing is difficult because generated plasma from preceding droplets push succeeding droplets out of the primary focal spot. Current droplet-to-droplet feedback control to re-align droplets to the primary focal spot is relatively slow. The system and method described herein adaptively pre-compensate for droplet push-out by directing droplets to a target position that is offset from the primary focal spot such that when a droplet is lased, the droplet is pushed by the laser beam into the primary focal spot to generate plasma. Over time, the EUV system learns to maintain real-time alignment of droplet position so plasma is generated consistently within the primary focal spot.

Abstract: A lithographic projection apparatus includes a support structure configured to hold a patterning device, the patterning device configured to pattern a beam of radiation according to a desired pattern; a substrate table configured to hold a substrate; a projection system configured to project the patterned beam onto a target portion of the substrate; a liquid supply system configured to provide liquid to a space between the projection system and the substrate; and a shutter configured to isolate the space from the substrate or a space to be occupied by a substrate.

Abstract: A fluid handling structure for a lithographic apparatus, the fluid handling structure having, at a boundary from a space configured to contain immersion fluid to a region external to the fluid handling structure: a meniscus pinning feature to resist passage of immersion fluid in a radially outward direction from the space; and a plurality of gas supply openings in a linear array at least partly surrounding and radially outward of the one or more meniscus pinning features, wherein the plurality of gas supply openings in a linear array are of a similar or the same size.

Abstract: A method of forming an imprint template using a substrate having an inorganic release layer and a layer of imprintable medium is disclosed. The method includes using a master imprint template to imprint a pattern into the imprintable medium, causing the imprintable medium to solidify, and etching the imprintable medium and the inorganic release layer to form a pattern in the inorganic release layer.

Abstract: A substrate has first and second target structures formed thereon by a lithographic process. Each target structure has two-dimensional periodic structure formed in a single material layer on a substrate using first and second lithographic steps, wherein, in the first target structure, features defined in the second lithographic step are displaced relative to features defined in the first lithographic step by a first bias amount that is close to one half of a spatial period of the features formed in the first lithographic step, and, in the second target structure, features defined in the second lithographic step are displaced relative to features defined in the first lithographic step by a second bias amount close to one half of said spatial period and different to the first bias amount.

Abstract: In a lithographic projection apparatus, a liquid supply system maintains liquid in a space between the projection system and the substrate. The liquid supply system may further include a de-mineralizing unit, a distillation unit, a de-hydrocarbonating unit, a UV radiation source, and/or a filter configured to purify the liquid. A gas content reduction device may be provided to reduce a gas content of the liquid. A chemical may be added to the liquid using an adding device to inhibit lifeform growth and components of the liquid supply system may be made of a material which is non-transparent to visible light such that growth of lifeforms may be reduced.

Abstract: A substrate handling system for an apparatus, the substrate handling system including a substrate table constructed to hold a substrate, a surrounding structure configured to surround the substrate, a sensor configured to determine a thickness of the substrate, and a control system configured to configure the apparatus responsive to a determination that the determined thickness is outside a thickness range associated with the surrounding structure.

Abstract: A method to adjust line-width roughness (LWR) in a lithographic apparatus, the method including receiving a value of LWR and/or image log slope (ILS) for each feature of a plurality of different features of a pattern to be imaged, using a patterning device, onto a substrate in a lithographic process, and evaluating a cost function including a lithographic parameter and the values of LWR and/or ILS to determine a value of the lithographic parameter that (i) reduces a bias between the LWR and/or ILS of the different features, or (ii) reduces a difference in the LWR and/or ILS of the different features between different lithographic apparatuses, or (iii) reduces a difference in the LWR and/or ILS of the different features between different patterning devices, or (iv) any combination selected from (i)-(iii).