Abstract: Methods are disclosed for measuring target structures formed by a lithographic process on a substrate. A grating structure within the target is smaller than an illumination spot and field of view of a measurement optical system. The optical system has a first branch leading to a pupil plane imaging sensor and a second branch leading to a substrate plane imaging sensor. A spatial light modulator is arranged in an intermediate pupil plane of the second branch of the optical system. The SLM imparts a programmable pattern of attenuation that may be used to correct for asymmetries between the first and second modes of illumination or imaging. By use of specific target designs and machine-learning processes, the attenuation patterns may also be programmed to act as filter functions, enhancing sensitivity to specific parameters of interest, such as focus.

Abstract: In a lithographic process, product units such as semiconductor wafers are subjected to lithographic patterning operations and chemical and physical processing operations. Alignment data or other measurements are made at stages during the performance of the process to obtain object data representing positional deviation or other parameters measured at points spatially distributed across each unit. This object data is used to obtain diagnostic information by performing a multivariate analysis to decompose a set of vectors representing the units in said multidimensional space into one or more component vectors. Diagnostic information about the industrial process is extracted using the component vectors. The performance of the industrial process for subsequent product units can be controlled based on the extracted diagnostic information.

Abstract: A lithographic apparatus includes: an object that is moveable in at least one direction; a control system to move the object in the at least one direction, wherein the control system is arranged to control movement of the object in the at least one direction in a frequency range of interest; and a conduit provided with a fluid, wherein the conduit is arranged on or in the object in a pattern, and wherein the pattern is such that an acceleration of the object in the at least one direction causes an acceleration pressure profile in the fluid along the conduit, the acceleration pressure profile not matching with a resonance pressure profile that corresponds to a standing wave mode in the fluid with a resonance frequency in the frequency range of interest.

Abstract: A lithographic apparatus includes a patterning device support to support a patterning device to form a patterned radiation beam, the patterning device support including a moveable structure movably arranged with respect to an object, a patterning device holder movably arranged relative to the movable structure and holding the patterning device, an actuator to move the movable structure relative to the object, and an ultra short stroke actuator to move the patterning device holder relative to the movable structure; a substrate support to hold a substrate; and a projection system to project the patterned radiation beam onto the substrate, a position measurement system for measuring a substrate positional error which is a difference between a desired position and an actual position of the substrate relative to a reference object; and a controller to move the actuator and the ultra short stroke actuator based on the substrate positional error.

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).

Abstract: A lithographic apparatus has shield which protects a functional subsystem form acoustic disturbances. The shield comprises a locally resonant sonic material for implementing the protecting. In an embodiment the shield comprises a panel formed by a cell or a plurality of cells comprising: a frame; an elastic membrane whose edge is fixed to the frame; and a mass attached to a location at the membrane at a non-zero distance from the edge.

Abstract: A fluid handling structure for a lithographic apparatus is disclosed, the fluid handling structure successively has, at a boundary from a space configured to contain immersion fluid to a region external to the fluid handling structure: an elongate opening or a plurality of openings arranged in a first line that, in use, are directed towards a substrate and/or a substrate table configured to support the substrate; a gas knife device having an elongate aperture in a second line; and an elongate opening or a plurality of openings adjacent the gas knife device.

Abstract: A lithographic apparatus includes a sensor, such as an alignment sensor including a self-referencing interferometer, configured to determine the position of an alignment target including a periodic structure. An illumination optical system focuses radiation of different colors and polarizations into a spot which scans the structure. Multiple position-dependent signals are detected and processed to obtain multiple candidate position measurements. Asymmetry of the structure is calculated by comparing the multiple position-dependent signals. The asymmetry measurement is used to improve accuracy of the position read by the sensor. Additional information on asymmetry may be obtained by an asymmetry sensor receiving a share of positive and negative orders of radiation diffracted by the periodic structure to produce a measurement of asymmetry in the periodic structure.

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 lithographic apparatus comprising an object table which carries an object. The lithographic apparatus may further comprise at least one sensor as part of a measurement system to measure a characteristic of the object table, the environment surrounding the lithographic apparatus or another component of the lithographic apparatus. The measured characteristic may be used to estimate the deformation of the object due to varying loads during operation of the lithographic apparatus, for example varying loads induced by a two-phase flow in a channel formed within the object table. Additionally, or alternatively, the lithographic apparatus comprises a predictor to estimate the deformation of the object based on a model. The positioning of the object table carrying the object can be controlled based on the estimated deformation.

Abstract: An electrostatic clamp (12) comprising an electrode (2), a layer of resistive material (6) located on the electrode, and a layer of dielectric (8) located on the resistive material, wherein the electrostatic clamp further comprises burls (10) which project from the layer of dielectric.

Abstract: In scatterometry, a merit function including a regularization parameter is used in an iterative process to find values for the scattering properties of the measured target. An optimal value for the regularization parameter is obtained for each measurement target and in each iteration of the iterative process. Various methods can be used to find the value for the regularization parameter, including the Discrepancy Principle, the chi-squared method and novel modifications of the Discrepancy Principle and the chi-squared method including a merit function.

Abstract: A computer-implemented method for improving a lithographic process for imaging a portion of a design layout onto a substrate using a lithographic projection apparatus comprising an illumination source and projection optics, the method including computing a multi-variable cost function of a plurality of design variables that are characteristics of the lithographic process, at least some of the design variables being characteristics of the illumination source and the design layout, the computing of the multi-variable cost function accounting for lens heating effects; and reconfiguring the characteristics of the lithographic process by adjusting the design variables until a predefined termination condition is satisfied.

Abstract: A substrate table supports a substrate holder to which a substrate is clamped for exposure. The substrate table has a plurality of e-pins spaced apart from and distributed around the center of the substrate holder to receive, and lower, a substrate onto the substrate holder prior to exposure, and to raise a substrate off the substrate holder after exposure. Tip portions of the e-pins and the corresponding apertures in the substrate holder have a shape in plan including at least one re-entrant, e.g. a cross shape.

Abstract: A lithographic apparatus including a barrier system and a device manufacturing method using such a lithographic apparatus. The barrier system is used to maintain a protected volume of gas within a barrier. The protected volume may be maintained when different components of the lithographic apparatus move relative to each other. The barrier system may be used in different locations within the lithographic apparatus. The geometry of the barrier affects how efficiently the protected volume is maintained, especially at high speeds. The geometry reduces the amount of ambient gas entering the protected volume from outside the barrier.

Abstract: A property of a target structure is measured based on intensity of an image of the target. The method includes (a) obtaining an image of the target structure; (b) defining a plurality of candidate regions of interest, each candidate region of interest comprising a plurality of pixels in the image; (c) defining an optimization metric value for the candidate regions of interest based at least partly on signal values of pixels within the region of interest; (d) defining a target signal function which defines a contribution of each pixel in the image to a target signal value. The contribution of each pixel depends on (i) which candidate regions of interest contain that pixel and (ii) optimization metric values of those candidate regions of interest.

Abstract: A lithographic apparatus is disclosed that has a first substrate table arranged to hold a substrate and a second substrate table arranged to hold a substrate, an imprint template holder arranged to hold an imprint template, and an imprintable medium dispenser, wherein the first substrate table is moveable between a first position located at or adjacent to the imprintable medium dispenser, and a second position located at or adjacent to the imprint template holder, and the second substrate table is moveable between the first and second positions, such that the first and second substrate tables swap positions.

Abstract: A lithographic apparatus including a support to support a patterning device, a substrate table to hold a substrate, and a projection system to project a radiation beam patterned by the patterning device onto a target portion of the substrate. A transparent layer is provided to protect the pattering device. The apparatus further includes a transparent layer deformation-determining device to determine a deformation profile of the transparent layer, the deformation profile of the transparent layer expressing a deformation of the transparent layer during a scanning movement of the lithographic apparatus, and a compensator device which is configured to control the projection system, the substrate table and/or the support in response to the deformation profile of the transparent layer to compensate for the deformation of the transparent layer during the scanning movement of the apparatus.

Abstract: The present invention relates to lithographic apparatuses and processes, and more particularly to tools for co-optimizing illumination sources and masks for use in lithographic apparatuses and processes. According to certain aspects, the present invention enables full chip pattern coverage while lowering the computation cost by intelligently selecting a small set of critical design patterns from the full set of clips to be used in source and mask optimization. Optimization is performed only on these selected patterns to obtain an optimized source. The optimized source is then used to optimize the mask (e.g. using OPC and manufacturability verification) for the full chip, and the process window performance results are compared. If the results are comparable to conventional full-chip SMO, the process ends, otherwise various methods are provided for iteratively converging on the successful result.

Abstract: A lithographic apparatus is disclosed. The lithographic apparatus includes a scatterometer configured to measure a property of the substrate. The scatterometer includes a radiation source configured to produce a radiated spot on a target on the substrate, where the radiated spot includes positions on the target. The scatterometer further includes a detector configured to generate measurement signals that correspond to respective ones of the positions of the radiated spot and a processor configured to output, based on the measurement signals, a single value that is representative of the property of the substrate.