Abstract: A source module for use in a lithographic apparatus is constructed to generate extreme ultra violet (EUV) and secondary radiation, and includes a buffer gas configured to cooperate with a source of the EUV radiation. The buffer gas has at least 50% transmission for the EUV radiation and at least 70% absorption for the secondary radiation.

Abstract: A liquid supply system for an immersion lithographic projection apparatus is disclosed in which a space is defined between the projection system, a barrier member and a substrate. The barrier member is not sealed such that, during use, immersion liquid is allowed to flow out the space and between the barrier member and the substrate.

Abstract: An inspection apparatus (for example a scatterometer) comprises: a substrate support for supporting a substrate and an optical system. An illumination system illuminates a target (T) with radiation. A positioning system (518) moves one or both of the optical system and the substrate support so as to position an individual target (T) relative to the optical system so that the imaging optics can use a portion of the diffracted radiation to form an image of the target structure on an image sensor (23). A liquid lens (722) is controlled (902) by feed-forward control to maintain said image stationary against vibration and/or scanning movement between the optical system and the target structure. In a second aspect, a liquid lens (1324, 1363) to correct chromatic aberration during measurements made at different wavelengths. This may improve focusing of the illumination on the target (T), and/or focusing of an image on the image sensor (23).

Abstract: A substrate has three or more overlay gratings formed thereon by a lithographic process. Each overlay grating has a known overlay bias. The values of overlay bias include for example two values in a region centered on zero and two values in a region centered on P/2, where P is the pitch of the gratings. Overlay is calculated from asymmetry measurements for the gratings using knowledge of the different overlay bias values and an assumed non-linear relationship between overlay and target asymmetry, thereby to correct for feature asymmetry. The periodic relationship in the region of zero bias and P/2 has gradients of opposite sign. The calculation allows said gradients to have different magnitudes as well as opposite sign. The calculation also provides information on feature asymmetry and other processing effects. This information is used to improve subsequent performance of the measurement process, and/or the lithographic process.

Abstract: The present invention provides methods and apparatus for facilitating the start up of a fuel droplet stream generator. During a start-up phase the fuel droplet stream generator is positioned so that the fuel droplets re emitted downwardly whereby gravity assists in the establishment of the stream. The droplets are monitored using a visualization system and once the stream is determined to have the desired characteristics the stream generator is moved to a second position of steady state use in which the droplet stream is emitted in a horizontal direction.

Abstract: The present invention discloses various system and process embodiments where wafer-metrology and direct measurements of the lithography apparatus characteristics are combined to achieve temporal drift reduction in a lithography apparatus/process using a simulation model. The simulation model may have sub-components. For example, a sub-model may represent a first set of optical conditions, and another sub-model may represent a second set of optical conditions. The first set of optical conditions may be a standard set of illumination conditions, and the second set may be a custom set of illumination conditions. Using the inter-relationship of the sub-models, stability control under custom illumination condition can be achieved faster without wafer metrology.

Abstract: Techniques for forming a target and for producing extreme ultraviolet light include releasing an initial target material toward a target location, the target material including a material that emits extreme ultraviolet (EUV) light when converted to plasma; directing a first amplified light beam toward the initial target material, the first amplified light beam having an energy sufficient to form a collection of pieces of target material from the initial target material, each of the pieces being smaller than the initial target material and being spatially distributed throughout a hemisphere shaped volume; and directing a second amplified light beam toward the collection of pieces to convert the pieces of target material to plasma that emits EUV light.

Abstract: A lithographic projection apparatus includes a support structure to hold a patterning device, the patterning device configured to pattern a beam of radiation according to a desired pattern; a projection system to project the patterned beam onto a target portion of a substrate; a substrate table configured to hold the substrate, the substrate table including a support surface to support an intermediary plate between the projection system and at least one of the substrate and an object positioned on the substrate table and not in contact with the at least one of the substrate and the object; and a liquid supply system to provide a liquid, through which the beam is to be projected, in a space between the projection system and the at least one of the substrate and the object.

Abstract: A lithographic manufacturing system produces periodic structures with feature sizes less than 10 nm and a direction of periodicity (D). A beam of radiation (1904) having a range of wavelengths in the EUV spectrum (1-100 nm or 1-150 nm) is focused into a spot (S) of around 5 ?m diameter. Reflected radiation (1908) is broken into a spectrum (1910) which is captured (1913) to obtain a target spectrum signal (ST). A reference spectrum is detected (1914) to obtain a reference spectrum signal (SR). Optionally a detector (1950) is provided to obtain a further spectrum signal (SF) using radiation diffracted at first order by the grating structure of the target. The angle of incidence (?) and azimuthal angle (?) are adjustable. The signals (ST, SR, SF) obtained at one or more angles are used to calculate measured properties of the target, for example CD and overlay.

Abstract: An immersion lithography apparatus comprises a temperature controller configured to adjust a temperature of a projection system, a substrate and a liquid towards a common target temperature. Controlling the temperature of these elements and reducing temperature gradients may improve imaging consistency and general lithographic performance. Measures to control the temperature may include controlling the immersion liquid flow rate and liquid temperature, for example, via a feedback circuit.

Abstract: An electrostatic clamp configured to, in use, hold an article, such as a reticle or a wafer in a lithographic apparatus. The clamp includes a lower portion; an upper portion formed of a dielectric material, and a plurality of electrodes disposed between the lower portion and the upper portion. The electrodes include a first electrode configured in use to be held at a first voltage, at least one intermediate electrode configured in use to be held at a second voltage, and a ground electrode. The at least one intermediate electrode is located between the first electrode and the ground electrode and the second voltage is between the first voltage and ground to reduce the voltage across a barrier between the electrodes and so reduce the risk of high-voltage breakdown.

Abstract: A method to determine the usefulness of an alignment mark of a first pattern in transferring a second pattern to a substrate relative to the first pattern already present on the substrate includes measuring the position of the alignment mark, modeling the position of the alignment mark, determining the model error between measured and modeled position, measuring a corresponding overlay error between first and second pattern and comparing the model error with the overlay error to determine the usefulness of the alignment mark. Subsequently this information can be used when processing next substrates thereby improving the overlay for these substrates. A lithographic apparatus and/or overlay measurement system may be operated in accordance with the method.

Abstract: An immersion liquid is provided comprising an ion-forming component, e.g. an acid or a base, which has a relatively high vapor pressure. Also provided are lithography processes and lithography systems using the immersion liquid.

Abstract: A table for a lithographic apparatus, the table having a catchment opening formed in an upper surface of the table, the catchment opening in fluid communication through the table with the environment of the table at a drain opening in a surface of the table other than the upper surface.

Abstract: A radiation system to generate a radiation emitting plasma, the radiation system include a fuel emitter to provide a fuel target at a plasma formation region, a first laser arranged to provide a first laser beam at the plasma formation region incident on the fuel target to generate a radiation emitting plasma, an imaging device arranged to obtain a first image of the radiation emitting plasma at the plasma formation region, the first image indicating at least one image property of the radiation emitting plasma, and a controller. The controller is arranged to receive the first image, and to generate at least one instruction based on the at least one image property of the radiation emitting plasma to modify operation of at least one component of the radiation system to reduce a detrimental effect of debris.

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: Disclosed is an inspection apparatus for use in lithography. It comprises a support for a substrate carrying a plurality of metrology targets; an optical system for illuminating the targets under predetermined illumination conditions and for detecting predetermined portions of radiation diffracted by the targets under the illumination conditions; a processor arranged to calculate from said detected portions of diffracted radiation a measurement of asymmetry for a specific target; and a controller for causing the optical system and processor to measure asymmetry in at least two of said targets which have different known components of positional offset between structures and smaller sub-structures within a layer on the substrate and calculate from the results of said asymmetry measurements a measurement of a performance parameter of the lithographic process for structures of said smaller size. Also disclosed are substrates provided with a plurality of novel metrology targets formed by a lithographic process.

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 method of correcting an optical image formed by an optical system, the method including obtaining a map indicative of a polarization dependent property of the optical system across a pupil plane of the optical system for each spatial position in an image plane of the optical system, combining the map indicative of the polarization dependent property of the optical system with a radiation map of the intensity and polarization of an input radiation beam to form an image map, and using the image map to correct an optical image formed by directing the input radiation beam through the optical system.

Abstract: A radiation source suitable for providing radiation to a lithographic apparatus generates radiation from a plasma (12) generated from a fuel (31) within an enclosure comprising a gas. The plasma generates primary fuel debris collected as a fuel layer on a debris-receiving surface ((33a), (33b)). The debris-receiving surface is heated to a temperature to maintain the fuel layer as a liquid, and to provide a reduced or zero rate of formation gas bubbles within the liquid fuel layer in order to reduce contamination of optical surfaces (14) by secondary debris arising from gas bubble eruption from the liquid fuel layer. Additionally or alternatively, the radiation source may have a debris receiving surface positioned and/or oriented such that substantially all lines normal to the debris receiving surface do not intersect an optically active surface of the radiation source.