Illumination adjustment device and lithography apparatus

Abstract

The illumination adjustment device includes a plate, a plurality of actuators, and a plurality of finger structures. The plurality of actuators include a plurality of coils disposed on the plate. The plurality of finger structures include a beryllium alloy material. Each of the plurality of finger structures is coupled to a corresponding one of the plurality of actuators via a magnet. The plurality of finger structures are independently moved using the plurality of actuators and positioned at least partially within a path of a radiation beam to block at least a portion of the beam, and adjust an intensity cross-section of the beam based on the movement and blockage.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Application No. 63 / 406,992, filed September 15, 2022, which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates to illumination systems, for example illumination conditioning systems for adjusting the cross-sectional intensity of an illumination beam used in lithographic apparatus and systems. [Background technology]

[0003] A lithographic apparatus is a machine that applies a desired pattern to a substrate, usually to a target portion of the substrate. Lithographic apparatus are used, for example, in the manufacture of integrated circuits (ICs). In that case, a patterning device, which may be a mask or a reticle, is used to generate a circuit pattern for an individual layer of the IC. This pattern can be transferred onto a target portion (e.g. comprising part of a die, one die or several dies) on the substrate (e.g. a silicon wafer). Transfer of the pattern is typically via imaging onto a layer of radiation-sensitive material (photoresist or simply "resist") provided on the substrate. In general, a single substrate will contain a network of adjacent target portions that are successively exposed. Known lithographic apparatus include so-called steppers and scanners. In a stepper, each target portion is irradiated such that the entire pattern is exposed onto it at once. In a scanner, each target portion is irradiated while the radiation beam scans the pattern in a given direction (the "scan" direction) and the substrate is synchronously scanned parallel or anti-parallel to this direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.

[0004] Another lithography system is an interference lithography system, which does not have a patterning device, but instead splits a light beam into two beams and uses a reflective system to cause the two beams to interfere at a target portion of the substrate. This interference forms a line on the target portion of the substrate.

[0005] Lithographic apparatuses typically include an illumination system that conditions the radiation generated by a radiation source before the radiation is incident on a patterning device. The illumination system can modify one or more characteristics of the radiation, such as, for example, polarization and / or illumination mode. The illumination system can include a uniformity correction system that corrects or reduces non-uniformities (e.g., intensity non-uniformities) present in the radiation. The uniformity correction system can employ actuating fingers inserted into the end of the radiation beam to correct for intensity variations. The spatial extent of the illumination that can be adjusted by the uniformity correction system depends, among other things, on the size of the fingers and the size of the actuators used to move the fingers in the uniformity correction system. Modifying the size of the fingers from a known, working design is not trivial because such modifications can lead to undesired changes in one or more characteristics of the radiation beam, such as, for example, the pupil formed by the radiation beam.

[0006] In order to achieve a high quality pattern transfer onto a substrate, it is desirable to control the cross-sectional intensity of the radiation beam and to correct for errors in radiation dose. It is problematic that a beam of radiation can have a non-conforming intensity profile. In lithographic processes, it is desirable to have a controllable radiation beam so that improved uniformity can be achieved. A patterning device imparts a pattern to the radiation beam which is projected onto the substrate. The imaging quality of this projection beam is affected by the uniformity of the beam. Summary of the Invention

[0007] Therefore, it is desirable to control the uniformity of the illumination so that the lithography tool can perform the lithography process as accurately and quickly as possible.

[0008] In some aspects, the illumination adjustment device may include a plate, a plurality of actuators, and a plurality of finger structures. The plurality of actuators may include a plurality of coils disposed on the plate. The plurality of finger structures may comprise a beryllium alloy material. Each of the plurality of finger structures may be coupled to a corresponding one of the plurality of actuators via a magnet. The plurality of finger structures may be configured to be independently moved using the plurality of actuators and positioned at least partially within a path of the radiation beam to block at least a portion of the beam and to adjust an intensity cross-section of the beam based on the movement and blocking.

[0009] In some aspects, the lithographic apparatus may include an illumination system and an illumination adjustment device. The illumination system may be configured to illuminate a pattern on a patterning device. The illumination adjustment device may include a plate, a plurality of actuators, and a plurality of finger structures. The plurality of actuators may comprise a plurality of coils arranged on the plate. The plurality of finger structures may comprise a beryllium alloy material. Each of the plurality of finger structures may be coupled to a corresponding one of the plurality of actuators via a magnet. The plurality of finger structures may be independently moved using the plurality of actuators and positioned at least partially in a path of a radiation beam to block at least a portion of the beam, and configured to adjust an intensity cross-section of the beam based on the movement and blocking.

[0010] In some aspects, the illumination conditioning device may include a plate, a plurality of actuators, and a plurality of finger structures. The plate may include fluid channels distributed throughout the plate. The fluid channels may be configured to circulate a cooling fluid throughout the plate and introduce cooling fluid to a central region of the plate before directing the cooling fluid to a peripheral region of the plate. The plurality of actuators may include a plurality of coils disposed on the plate. At least a portion of the fluid channel may be disposed between at least two of the coils. Each of the plurality of finger structures may be coupled to a corresponding one of the plurality of actuators via a magnet. The plurality of finger structures may be independently moved using the plurality of actuators and configured to be at least partially positioned within a path of a radiation beam to block at least a portion of the beam and to adjust an intensity cross-section of the beam based on the movement and blocking.

[0011] In some aspects, the lithographic apparatus may include an illumination system and an illumination conditioning device. The illumination system may be configured to illuminate a pattern on a patterning device. The illumination conditioning device may include a plate, a plurality of actuators, and a plurality of finger structures. The plate may include fluid channels distributed throughout the plate. The fluid channels may be configured to circulate a cooling fluid throughout the plate and introduce cooling fluid to a central region of the plate before directing cooling fluid to a peripheral region of the plate. The plurality of actuators may include a plurality of coils disposed on the plate. At least a portion of the fluid channel may be disposed between at least two of the coils. Each of the plurality of finger structures may be coupled to a corresponding one of the plurality of actuators via a magnet. The plurality of finger structures may be independently moved using the plurality of actuators and configured to be at least partially positioned within a path of a radiation beam to block at least a portion of the beam and to adjust an intensity cross-section of the beam based on the movement and blocking.

[0012] Further features of various aspects of the present disclosure are described in detail below with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to the particular aspects described herein. These aspects are presented for illustrative purposes only. Additional aspects will be apparent to those skilled in the relevant art based on the teachings contained herein. [Brief explanation of the drawings]

[0013] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate the disclosure and, together with the detailed description, serve to explain the principles of the disclosure and to enable those skilled in the relevant art to make and use the embodiments described herein.

[0014] [Figure 1A] 1 illustrates a reflective lithographic apparatus according to some aspects;

[0015] [Figure 1B] 1 illustrates a transmissive lithographic apparatus according to some aspects;

[0016] [Figure 2] FIG. 1 illustrates a reflective lithographic apparatus in more detail, according to some aspects.

[0017] [Figure 3] FIG. 1 illustrates a lithography cell according to some aspects.

[0018] [Figure 4] FIG. 1 illustrates a uniformity correction system according to some aspects.

[0019] [Figure 5] 1 illustrates a finger structure that can be used in a uniformity correction system, according to some aspects.

[0020] [Figure 6]1A-1C illustrate plates that can be used in a uniformity correction system, according to some aspects.

[0021] Features of the present disclosure will become more apparent from the following detailed description of the invention when taken in conjunction with the drawings, in which like reference characters identify corresponding elements. Like reference numbers in the drawings generally indicate identical, functionally similar, and / or structurally similar elements. Also, the leftmost digit(s) of a reference number generally identifies the drawing in which the reference number first appears. Unless otherwise indicated, the drawings provided throughout this disclosure should not be considered to be drawn to scale. DETAILED DESCRIPTION OF THE INVENTION

[0022] References herein to the embodiments described, and to "one embodiment," "an embodiment," "an exemplary embodiment," "one example of an embodiment," and the like, indicate that the described embodiment may include a particular feature, structure, or characteristic, but not all embodiments necessarily include that particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with one embodiment, it is understood that such feature, structure, or characteristic can be combined and operative in other embodiments, whether or not explicitly stated.

[0023] For ease of description, spatially relative terms such as "lower," "bottom," "upper," "over," "top," and "upper" may be used herein to describe the relationship of one element or feature to another element or feature shown in the figures. These spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation shown. The device may be in other orientations (rotated 90 degrees or at other orientations) and the spatially relative descriptions used herein may be interpreted accordingly.

[0024] As used herein, the terms "about," "approximately," and the like indicate a given quantity value that may vary based on a particular technique. Based on a particular technique, the terms "about," "approximately," and the like may indicate a given quantity value that varies within a range of, for example, 10 to 30% of the value (e.g., ±10%, ±20%, or ±30% of the value).

[0025] Aspects of the present disclosure may be implemented in hardware, firmware, software, or any combination thereof. Aspects of the present disclosure may also be implemented as instructions stored on a computer-readable medium, which may be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, machine-readable media include read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, electrical, optical, acoustical, or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals), etc. Furthermore, firmware, software, routines, and / or instructions may be described herein as performing particular operations. However, such description is for convenience only, and it should be understood that such operations result from a computing device, processor, controller, or other device executing the firmware, software, routines, instructions, etc. The term “machine-readable medium” may be interchangeable with similar terms, such as “computer program product,” “computer-readable medium,” “non-transitory computer-readable medium,” etc. The term "non-transitory" may be used herein to characterize one or more forms of computer-readable media other than transitory, propagating signals.

[0026] However, before describing these aspects in more detail, it is helpful to present an exemplary environment in which aspects of the present disclosure may be implemented.

[0027] Exemplary Lithography System

[0028] 1A and 1B show lithographic apparatus 100 and lithographic apparatus 100', respectively, in which some aspects of the present disclosure may be implemented. Lithographic apparatus 100 and lithographic apparatus 100' each include an illumination system (illuminator) IL configured to condition a radiation beam B (e.g., deep ultraviolet radiation or extreme ultraviolet radiation), a support structure (e.g., mask table) MT configured to support a patterning device (e.g., a mask, reticle, or dynamic patterning device) MA and connected to a first positioner PM configured to accurately position the patterning device MA, and a substrate table (e.g., wafer table) WT configured to hold a substrate (e.g., a resist-coated wafer) W and connected to a second positioner PW configured to accurately position the substrate W. Lithographic apparatus 100 and 100' also include a projection system PS configured to project a pattern imparted to radiation beam B by patterning device MA onto a target portion C of the substrate W (e.g., comprising one or more dies). In lithographic apparatus 100, patterning device MA and projection system PS are reflective. In lithographic apparatus 100', patterning device MA and projection system PS are transmissive.

[0029] The illumination system IL may include various optical components, such as refractive, reflective, catadioptric, magnetic, electromagnetic, electrostatic or other types of optical components, or any combination thereof, to direct, shape and / or control the radiation beam B. The illumination system IL may also include sensors ES that provide measurements of one or more of, for example, energy per pulse, photon energy, intensity, average power, etc. The illumination system IL may include a measurement sensor MS for measuring displacement of the radiation beam B, and a uniformity compensator UC that allows the uniformity of the illumination slit to be controlled. The measurement sensor MS may also be located at other locations. For example, the measurement sensor MS may be located on or near the substrate table WT.

[0030] The support structure MT holds the patterning device MA in a manner that depends on the orientation of the patterning device MA relative to a reference frame, the design of at least one of lithographic apparatuses 100 and 100′, and other conditions, such as whether or not the patterning device MA is held in a vacuum environment. The support structure MT may use mechanical, vacuum, electrostatic, or other clamping techniques to hold the patterning device MA. The support structure MT may, for example, be a fixed or movable frame or table. By using sensors, the support structure MT can ensure that the patterning device MA is at a desired position, for example with respect to the projection system PS.

[0031] The term "patterning device" MA should be interpreted broadly as referring to any device that can be used to impart a radiation beam B with a pattern in its cross-section to create a pattern in a target portion C of a substrate W. The pattern imparted to the radiation beam B may correspond to a particular functional layer in a device being created in the target portion C to form an integrated circuit.

[0032] Patterning device MA may be transmissive (such as lithographic apparatus 100' in FIG. 1B) or reflective (such as lithographic apparatus 100 in FIG. 1A). Examples of patterning devices MA include reticles, masks, programmable mirror arrays, or programmable LCD panels. Masks are well known in lithography, and include mask types such as binary, alternating phase-shift, or attenuated phase-shift, as well as various hybrid mask types. An example of a programmable mirror array is a matrix arrangement of small mirrors, each of which can be individually tilted so as to reflect an incoming radiation beam B in different directions. The tilted mirrors impart a pattern to a radiation beam B, which is reflected by the matrix of small mirrors.

[0033] The term "projection system" PS can encompass any type of projection system, including refractive, reflective, catadioptric, magnetic, electromagnetic or electrostatic optical systems, or any combination thereof, as appropriate depending on the exposure radiation used and other factors such as the use of an immersion liquid or a vacuum on the substrate W. For EUV radiation or electron beam radiation, a vacuum environment may be used, as other gases may be too absorbing for the radiation or electrons. Therefore, a vacuum environment may be provided throughout the beam path using a vacuum wall and vacuum pumps.

[0034] Lithographic apparatus 100 and / or lithographic apparatus 100' may be of a type having two (dual stage) or more substrate tables WT (and / or two or more mask tables). In such a "multiple stage" apparatus, the additional substrate tables WT may be used in parallel, or one or more substrate tables WT may be used for exposure while one or more other tables perform preparatory steps. In some cases, the additional tables need not be substrate tables WT.

[0035] The lithographic apparatus may be of a type in which at least a portion of the substrate may be covered by a liquid having a relatively high refractive index, such as water, so as to fill a space between the projection system and the substrate. Immersion liquids may also be applied to other spaces in the lithographic apparatus, for example, between the mask and the projection system. Immersion techniques are well known in the art for increasing the numerical aperture of projection systems. The term "immersion" as used herein does not imply that a structure, such as a substrate, must be immersed in liquid. For example, a liquid may be disposed between the projection system and the substrate during exposure.

[0036] 1A and 1B, the illuminator IL receives a radiation beam from a radiation source SO. The radiation source SO and the lithographic apparatus 100, 100' may be separate physical entities, for example if the radiation source SO is an excimer laser. In such cases, the radiation source SO is not considered to form part of the lithographic apparatus 100 or 100', and the radiation beam B passes from the radiation source SO to the illuminator IL using a beam delivery system BD (in FIG. 1B) that may, for example, include appropriate directing mirrors and / or beam expanders. In other aspects, the radiation source SO may be an integral part of the lithographic apparatus 100, 100', for example if the radiation source SO is a mercury lamp. A radiation system may comprise the radiation source SO, the illuminator IL, and / or the beam delivery system BD.

[0037] The illuminator IL may include an adjuster AD (in FIG. 1B) for adjusting the angular intensity distribution of the radiation beam. Generally, at least the outer and / or inner radial extent (commonly referred to as “σ-outer” and “σ-inner,” respectively) of the intensity distribution in a pupil plane of the illuminator may be adjusted. In addition, the illuminator IL may comprise various other components (in FIG. 1B), such as an integrator IN and a condenser CO. The illuminator IL may be used to adjust the radiation beam B to have a desired uniformity and intensity distribution in its cross-section. The desired uniformity of the radiation beam B may be maintained by using a uniformity compensator UC. The uniformity compensator UC comprises a number of protrusions (e.g., fingers) adjustable in the path of the radiation beam B to control the uniformity of the radiation beam B. A sensor ES may be used to monitor the uniformity of the radiation beam B.

[0038] Referring to FIG. 1A, a radiation beam B is incident on a patterning device (e.g., mask) MA, which is held on a support structure (e.g., mask table) MT, and is patterned by the patterning device MA. In lithographic apparatus 100, the radiation beam B is reflected from the patterning device (e.g., mask) MA. After reflecting from the patterning device (e.g., mask) MA, the radiation beam B passes through a projection system PS, which focuses the radiation beam B onto a target portion C of a substrate W. A second positioner PW and a position sensor IF2 (e.g., an interferometer device, a linear encoder, or a capacitance sensor) can be used to accurately move the substrate table WT (e.g., to position different target portions C in the path of the radiation beam B). Similarly, a first positioner PM and another position sensor IF1 can be used to accurately position the patterning device (e.g., mask) MA relative to the path of the radiation beam B. Patterning device (eg mask) MA and substrate W may be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2.

[0039] Referring to FIG. 1B, radiation beam B is incident on a patterning device (e.g., mask MA), which is held on a support structure (e.g., mask table MT), and is patterned by the patterning device. After passing through the mask MA, radiation beam B passes through a projection system PS, which focuses the beam onto a target portion C of a substrate W. The projection system has a pupil PPU that is conjugate with an illumination system pupil IPU. A portion of the radiation emerges from the intensity distribution at the illumination system pupil IPU and passes through the mask pattern without being affected by diffraction at the mask pattern, creating an image of the intensity distribution at the illumination system pupil IPU. A desired uniformity of radiation beam B can be maintained by using a uniformity compensator UC to control the uniformity of radiation beam B. A sensor ES can be used to monitor the uniformity of radiation beam B.

[0040] The projection system PS projects an image of the mask pattern MP onto a photoresist layer coated on the substrate W. Here, the image of the mask pattern MP is formed by diffracted beams generated from the mark pattern MP by radiation from the intensity distribution. For example, the mask pattern MP can include an array of lines and spaces. Diffraction of the radiation at the array, other than the zeroth-order diffraction, generates a deflected diffracted beam with a change in direction perpendicular to the lines. The undiffracted beam (the so-called zeroth-order diffracted beam) passes through the pattern without any change in propagation direction. The zeroth-order diffracted beam passes through an upper lens or upper lens group of the projection system PS, which is upstream of the conjugate pupil PPU of the projection system PS, and reaches the conjugate pupil PPU. The portion of the intensity distribution in the plane of the conjugate pupil PPU associated with the zeroth-order diffracted beam is an image of the intensity distribution in the illumination system pupil IPU of the illumination system IL. The aperture device PD is, for example, positioned in a plane containing the conjugate pupil PPU of the projection system PS, or substantially in that plane.

[0041] The projection system PS is configured to capture (e.g., using a lens or lens group L) the zeroth, first, and / or higher-order diffracted beams (not shown). In some embodiments, the resolution-enhancing effect of dipole illumination can be exploited by using dipole illumination to image a line pattern extending in a direction perpendicular to the line. For example, a first-order diffracted beam interferes with a corresponding zeroth-order diffracted beam at the level of the wafer W to create an image of the line pattern MP with the best possible resolution and process window (i.e., a combination of usable depth of focus and tolerable exposure dose deviation). In some embodiments, astigmatism can be reduced by providing a radiation pole (not shown) in an opposing quadrant of the illumination system pupil IPU. Furthermore, in some embodiments, astigmatism can be reduced by blocking the zeroth-order beam associated with the radiation pole in the opposing quadrant at the conjugate pupil PPU of the projection system. This is described in detail in U.S. Pat. No. 7,511,799 B2, issued March 31, 2009, the entire contents of which are incorporated herein by reference.

[0042] The substrate table WT may be accurately moved (e.g. to position various target portions C in the path of the radiation beam B) using the second positioner PW and a position sensor IFD (e.g. an interferometer device, a linear encoder or a capacitance sensor). Similarly, the first positioner PM and a further position sensor (not shown in FIG. 1B) may be used to accurately position the mask MA with respect to the path of the radiation beam B (e.g. after mechanical retrieval from a mask library or during a scan).

[0043] In general, movement of the mask table MT may be realized using a long-stroke module (coarse positioning) and a short-stroke module (fine positioning), which form part of the first positioner PM. Similarly, movement of the substrate table WT may be realized using long-stroke and short-stroke modules, which form part of the second positioner PW. In the case of a stepper (as opposed to a scanner), the mask table MT may be connected to a short-stroke actuator, or may be fixed. The mask MA and substrate W may be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2. The substrate alignment marks occupy dedicated target portions (as shown) but may be located in spaces between target portions (known as scribe-lane alignment marks). Similarly, in situations in which more than one die is provided on the mask MA, the mask alignment marks may be located between the dies.

[0044] When the mask table MT and patterning device MA are inside the vacuum chamber V, an in-vacuum robot IVR can be used to move a patterning device, such as a mask, into or out of the vacuum chamber V. Alternatively, when the mask table MT and patterning device MA are outside the vacuum chamber, an out-vacuum robot can be used for various transfer tasks, similar to the in-vacuum robot IVR. Both the in-vacuum robot and the out-vacuum robot can be calibrated for smooth transfer of any payload (e.g., a mask) to a fixed kinematic mount of the transfer station.

[0045] Lithographic apparatus 100 and 100' can be used in at least one of the following modes:

[0046] 1. In step mode, the support structure (e.g. mask table) MT and substrate table WT remain essentially stationary, and an entire pattern imparted to the radiation beam B is projected onto a target portion C in one go (i.e. a single static exposure), while the substrate table WT is then moved in the X and / or Y direction so that a different target portion C can be exposed.

[0047] 2. In scan mode, the support structure (e.g. mask table) MT and the substrate table WT are scanned synchronously (i.e. a single dynamic exposure) while a pattern imparted to the radiation beam B is projected onto a target portion C. The velocity and direction of the substrate table WT relative to the support structure (e.g. mask table) MT may be determined by the (de-)magnification and image reversal characteristics of the projection system PS.

[0048] 3. In another mode, the support structure (e.g. mask table) MT holds a programmable patterning device and is kept substantially stationary, while the substrate table WT is moved or scanned while a pattern imparted to the radiation beam B is projected onto a target portion C. A pulsed radiation source SO can be employed, with the programmable patterning device being updated as required with each movement of the substrate table WT, or between successive radiation pulses during a scan. This mode of operation is readily adaptable to maskless lithography, employing a programmable patterning device such as a programmable mirror array.

[0049] Combinations and / or variations on the described modes of use or entirely different modes of use may also be employed.

[0050] In a further aspect, the lithographic apparatus 100 includes an extreme ultraviolet (EUV) light source configured to generate an EUV radiation beam for EUV lithography. Typically, the EUV light source is configured in a radiation system, and a corresponding illumination system is configured to condition the EUV radiation beam of the EUV light source.

[0051] FIG. 2 shows lithographic apparatus 100 in more detail, including a source collector apparatus SO, an illumination system IL, and a projection system PS. The source collector apparatus SO is constructed and arranged to maintain a vacuum environment in an enclosure 220 of the source collector apparatus SO. The EUV radiation-emitting plasma 210 can be formed by a discharge-produced plasma source. The EUV radiation can be generated by a gas or vapor, such as Xe gas, Li vapor, or Sn vapor, that is generated such that the EUV radiation-emitting plasma 210 emits radiation in the EUV range of the electromagnetic spectrum. The EUV radiation-emitting plasma 210 can be generated, for example, by a discharge that causes an at least partially ionized plasma. A partial pressure of, for example, 10 Pa of Xe, Li, Sn vapor, or any other suitable gas or vapor can be used for efficient generation of radiation. In some embodiments, an excited tin (Sn) plasma (e.g., excited via a laser) is provided to generate EUV radiation.

[0052] Radiation emitted by the EUV radiation-emitting plasma 210 passes from the source chamber 211 to the collector chamber 212 through an optional gas barrier or contaminant trap 230 (sometimes referred to as a contaminant barrier or foil trap) located in or behind an opening in the source chamber 211. The contaminant trap 230 may include a channel structure. The contaminant trap 230 may also include a gas barrier or a combination of a gas barrier and a channel structure. The contaminant trap or contaminant barrier 230 further described herein includes at least a channel structure.

[0053] Collector chamber 212 may include a radiation collector CO, which may be a so-called grazing incidence collector. Radiation collector CO has an upstream radiation collector side 251 and a downstream radiation collector side 252. Radiation passing through collector CO may be reflected by a grating spectral filter 240 and focused at a virtual source point INTF. The virtual source point INTF is commonly called an intermediate focus, and the source collector arrangement is arranged such that the intermediate focus INTF is located at or near an opening 219 in the enclosure structure 220. The virtual source point INTF is an image of the EUV radiation-emitting plasma 210. The grating spectral filter 240 is used to suppress, in particular, infrared (IR) radiation.

[0054] The radiation then passes through an illumination system IL, which may include a faceted field mirror device 222 and a faceted pupil mirror device 224 arranged to provide a desired angular distribution and a desired uniformity of radiation intensity of the radiation beam 221 at the patterning device MA. Reflection of the radiation beam 221 off the patterning device MA, which is held by a support structure MT, forms a patterned beam 226, which is imaged by the projection system PS via reflective elements 228, 229 onto a substrate W, which is held by a wafer stage or substrate table WT.

[0055] In general, there may be more elements in illumination optics unit IL and projection system PS than shown. Grating spectral filter 240 is dependent on the type of lithographic apparatus and is not required. Furthermore, there may be more mirrors than shown in Figure 2; for example, there may be one to six additional reflective elements in projection system PS than shown in Figure 2.

[0056] In some aspects, the illumination optics unit IL may include a sensor ES that provides measurements of one or more of, for example, energy per pulse, photon energy, intensity, average power, etc. The illumination optics unit IL may include a measurement sensor MS for measuring displacement of the radiation beam B, and a uniformity compensator UC that enables controlling the uniformity of the illumination slit. The measurement sensor MS may also be located at other positions. For example, the measurement sensor MS may be located on or near the substrate table WT.

[0057] Collector optic CO is depicted as a nested collector with grazing incidence reflectors 253, 254, 255, as just one example of a collector (or collector mirror), as shown in Figure 2. The grazing incidence reflectors 253, 254, 255 are arranged axisymmetrically about the optical axis O, and this type of collector optic CO is preferably used in combination with a discharge-produced plasma source, often referred to as a DPP source.

[0058] Exemplary Lithography Cell

[0059] FIG. 3 illustrates a lithography cell 300, sometimes referred to as a lithocell or cluster, according to some embodiments. Lithography apparatus 100 or 100′ can form a part of lithography cell 300. Lithography cell 300 can also include one or more devices for performing pre-exposure and post-exposure processes on a substrate. Conventionally, these include a spin coater SC for depositing a resist layer, a developer DE for developing exposed resist, a chill plate CH, and a bake plate BK. A substrate handler (robot) RO picks up substrates from input / output ports I / O1 and I / O2, moves them between different process tools, and delivers them to a loading bay LB of lithography apparatus 100 or 100′. These devices are often collectively referred to as a track and are under the control of a track control unit TCU. The track control unit TCU is itself controlled by an upper control system SCS, which also controls the lithography apparatus via a lithography control unit LACU. In this way, the various devices can be operated to maximize throughput and processing efficiency.

[0060] Exemplary Uniformity Correction System

[0061] FIG. 4 illustrates a portion of a uniformity correction system 400 according to some embodiments. In some embodiments, the uniformity correction system 400 may correspond to the uniformity compensator UC of FIGS. 1A, 1B, and 2. The uniformity correction system 400 includes a plurality of uniformity compensator elements 404 (e.g., fingers). Each of the uniformity compensator elements 404 includes a distal end 406. The uniformity correction system 400 can operate in conjunction with one or more sensors (e.g., ES and / or MS (FIGS. 1A, 1B, and 2)) to monitor and adjust the intensity profile of the radiation beam.

[0062] FIG. 4 illustrates a cross-slot illumination 408. The cross-slot illumination 408 may also be referred to as a cross-section of a radiation beam, a cross-section along the path of a radiation beam, an illumination slit, etc. The cross-slot illumination 408 is represented as a 2D intensity map having different intensity regions 410, 412, and 414. For example, intensity region 410 has a low relative intensity and is located at the outer portion of the cross-slot illumination 408. Conversely, intensity region 414 has a high relative intensity and is located toward the central portion of the cross-slot illumination 408. In some embodiments, the shape of the cross-slot illumination 408 is substantially arcuate. Each distal end 406 comprises a straight distal end oriented to generally follow the curvature of the arcuate shape. In some embodiments, the shape of the cross-slot illumination 408 has a substantially rectangular shape (not shown), and each distal end comprises a straight distal end oriented to generally follow the rectangular shape. Each of the uniformity compensator elements 404 is attached to a corresponding actuator (not shown).

[0063] In some embodiments, the uniformity correction system 400 can modify or adjust an illumination beam used in a lithography operation. For example, each of the uniformity compensator elements 404 can be adjusted in the path of the illumination beam (e.g., at least the portion overlapping the cross-slot illumination 408) using a corresponding actuator to conform the intensity profile of the cross-slot illumination 408 to a selected intensity profile. Thus, the uniformity correction system 400 can also be referred to as an illumination adjustment device. Exemplary operations of uniformity compensators can be found commonly in U.S. Pat. No. 8,629,973 B2, filed May 28, 2010, and U.S. Pat. No. 9,134,620 B2, filed April 12, 2012, which are incorporated herein by reference in their entireties.

[0064] In some embodiments, one function of the uniformity correction system 400 is to condition the beam of radiation such that the interaction between the beam of radiation and the uniformity correction system 400 results in a beam of radiation having intensity characteristics that meet given specifications. For example, in a lithography process, it may be important to use a very specific dose of radiation to ensure that the pattern is transferred from the mask to the wafer with as little error as possible. The cross-sectional intensity of the radiation beam may vary over time. This variation may increase the likelihood of errors in the pattern transfer. The uniformity correction system 400 may be used to control the cross-sectional intensity of the beam of radiation to reduce errors in the pattern transfer.

[0065] The term "throughput" is generally understood as the amount of material or article passing through a system or process. In some aspects, the term "throughput" may be used to characterize the speed of lithographic manufacturing. For example, throughput may refer to the rate at which lithographic manufacturing is completed on a wafer, or the rate at which a wafer clears a particular manufacturing step and moves on to the next. Throughput may be a performance indicator of a lithographic apparatus. It is desirable for a lithographic apparatus to output as many products as possible in as short a time as possible. Lithographic manufacturing may comprise several complex processes. Each part of the process may involve trade-offs that balance quality (e.g., sub-nanometer accuracy, high yield) with drawbacks (e.g., manufacturing delays, cost). For example, to improve pattern transfer accuracy, lithography may include rapidly actuating compensator fingers to adjust the radiation beam (to reduce pattern transfer errors).

[0066] However, in some embodiments, mechanical systems such as uniformity correction systems can have vibration problems (e.g., resonant modes). Depending on the finger material and dimensions, vibration problems can become more pronounced at higher actuation speeds. Actuation speeds can be slowed to reduce the effects of vibration modes, but at the expense of reduced throughput. Furthermore, high-speed operation generates more heat, which can increase the likelihood of mechanical failure and shorten the lifespan of affected components, negatively impacting the overall performance of the uniformity correction system. Embodiments described herein implement devices and features for reducing the effects of vibration and heat in uniformity correction systems.

[0067] FIG. 5 illustrates a finger structure 500 that can be used in a uniformity correction system according to some embodiments. In some embodiments, the finger structure 500 may include a body 502 and a tip 504. The actuator portion of the finger structure 500 may include a coil 508 and a magnet 510. The coil 508 may be disposed on a plate 506. The magnet 510 may be a magnet system (e.g., one or more magnets). The finger structure 500 may also include one or more flexures 512. The structure and function of the uniformity compensator element 404 (FIG. 4) may be designed according to the finger structure 500, as described herein.

[0068] In some embodiments, the finger structure 500 may be positioned proximate to the path of the radiation beam 514. The cross-section of the radiation beam 514 may correspond to the cross-slot illumination 408 (FIG. 4). The radiation beam 514 may illuminate a patterning device 516. The patterning device 516 may impart a pattern to the radiation beam 514 such that an image of the pattern is projected from the patterning device 516 onto a substrate (pattern transfer). The patterning device 516 may be reflective or transmissive. It is important that the intensity profile of the radiation beam 514 meets the tolerances of the lithography process. One or more finger structures may be used to control the intensity profile of the radiation beam 514. In the case of a group of finger structures, each finger structure 500 may be moved independently of the other finger structures. The finger structure 500 may be positioned at least partially within the path of the radiation beam 514 and block at least a portion of the beam. By moving the finger structures 500 into and / or out of the radiation beam 514, the intensity cross-section of the beam can be adjusted.

[0069] In some embodiments, the material of the finger structure 500 may also have improved thermal and chemical stability. For example, the thermal conductivity of a beryllium alloy may be higher than other candidate materials with similar stiffness and density. Furthermore, a beryllium alloy may be more corrosion resistant in the partial vacuum environment typically used in EUV lithography tools. For example, the material may be resistant to dilute hydrogen gas.

[0070] In some embodiments, plate 506 may generate significant heat due to the power supplied to coil 508. Plate 506 may include multiple coils for driving multiple finger structures.

[0071] In some embodiments, the one or more flexures 512 can reduce vibration of the finger structure 500, particularly for movement along the length of the finger structure 500 (e.g., along the y-axis as shown in FIG. 5 ). While the one or more flexures 512 can provide some vibration control along the width (x-axis) of the finger structure 500, it can be difficult to implement tighter vibration control in the limited space available when multiple finger structures are placed side-by-side (e.g., as depicted in FIG. 4 ). The width dimension can be smaller than and perpendicular to the length. Vibration along the x-axis is also referred to as lateral vibration, lateral vibration, transverse vibration, etc. To avoid this problem, the finger structure 500 can comprise an ultralight and ultrastiff material, such as a beryllium alloy. In a non-limiting example, the body 502 can be formed from a beryllium alloy. The lightness of the beryllium alloy facilitates high-speed actuation of the finger structure 500, while the increased stiffness can change the bandwidth of the vibration mode so that vibrations are damped at higher actuation speeds. The properties of the beryllium alloy help to increase the lower frequency limit of the vibration modes (i.e., the frequency at which vibrations can absorb energy from actuation). The minimum frequency of the lateral vibration mode can be pushed to, for example, about 130 Hz or higher, about 160 Hz or higher, about 180 Hz or higher, or about 200 Hz or higher.

[0072] FIG. 6 illustrates a plate 606 that can be used in a uniformity correction system according to some embodiments. In some embodiments, the plate 606 may correspond to the plate 506 of FIG. 5. The plate 606 may include a plurality of coil regions 618 and a fluid channel 620. An actuator coil (e.g., the coil 508 (FIG. 5)) may be disposed in each of the coil regions 618. The plate 606 may be assembled with a plurality of finger structures (e.g., the finger structure 500 (FIG. 5)) to form a uniformity correction system (e.g., the uniformity correction system 400 (FIG. 4)). The fluid channel 620 may include an inlet 622 and an outlet 624.

[0073] In some embodiments, as the uniformity correction system is used more vigorously (e.g., more power is supplied to the coil for faster operation), plate 606 may accumulate a significant amount of heat, resulting in reduced device performance or even irreversible damage. Therefore, fluid channel 620 can provide cooling fluid to cool plate 606 of the uniformity correction assembly. In one example, fluid channel 620 can direct cooling fluid around the periphery (illustrated as dashed line 626) of plate 606. While such a design is desirable for its simplicity, a drawback of this design is that the cooling fluid has limited ability to cool the center of plate 606. The resulting thermal gradient can affect the operational function of the uniformity correction system and may also affect the accuracy of positioning of the finger structures. Therefore, fluid channel 620 can be configured to circulate cooling fluid throughout plate 606. Furthermore, cooling fluid can be introduced to the central region of plate 606 (e.g., via inlet 622) before being delivered to the peripheral region of plate 606, or vice versa. Fluid channel 620 can also have a serpentine structure. Coil regions 618 can be arranged in rows. Fluid channel 620 can be present between every row of coil regions 618 to optimize cooling. Fluid channel 620 can be located between two or more coils to allow cooling fluid to flow adjacent to every heating coil. This may not be possible if fluid channel 620 were shaped like dashed line 626.

[0074] In some embodiments, the inlets and outlets of a cooling system can be designed to accommodate space constraints. A space-saving design can include having the inlet 622 and outlet 624 on the same side of the plate 606 so that cooling fluid supply and return lines can be positioned side-by-side. In this context, side need not refer strictly to an edge or periphery. For example, as shown in FIG. 6 , a line 628 may generally bisect the plate 606, thereby defining an upper side (above line 628) and a lower side (below line 628). And, according to this non-limiting example, the inlet 622 and outlet 624 can both be located on the lower side (i.e., the side below line 628).

[0075] In some embodiments, plate 606 may be provided with multiple quadrants (e.g., as defined by illustrative lines 630 and 632), and according to this non-limiting example, inlet 622 and outlet 624 may both be located in the same quadrant.

[0076] In some embodiments, where space constraints are less stringent, the inlet 622 and outlet 624 may be located on different sides or in different quadrants.

[0077] In some embodiments, the plate 606 can have a thickness along the height direction. The height direction, i.e., thickness, in FIG. 6 may be defined perpendicular to the page. The fluid channels 620 may be arranged at a first height or plane. In other words, the distribution and arrangement of the fluid channels 620 may define a first plane. The inlets 622 and / or outlets 624 may be arranged on a second plane offset from the first plane. This arrangement may be particularly useful for fitting the inlets 622 and outlets 624 to be on the same side or in the same quadrant. As shown in FIG. 6, the inlets 622 may be routed over a portion of the fluid channels 620 so as not to interfere with the intended flow path of the cooling fluid. In some embodiments, it is desirable to reduce the volume and footprint of the uniformity correction system (e.g., by designing it to have a small thickness, by designing the gaps between the magnets and the plate 506 and between the magnets 510 as small as possible, etc. (FIG. 5)). In some embodiments, the cooling scheme may route the flow out-of-plane from the coil. However, this can significantly increase the gap and / or reduce overall performance. Thus, in some embodiments, the flow may be along the coil rather than out-of-plane.

[0078] In some embodiments, the plate 606 may include multiple sensor regions 634. Temperature sensors (e.g., thermistors) may be disposed in the sensor regions 634. As shown by the distribution of the sensor regions 634 in FIG. 6 , the temperature sensors may cover a wide area of ​​the plate 606, allowing for monitoring of the temperature of the cooling fluid as it progresses from the central region of the plate 606 to the peripheral region of the plate 606. Sensing the temperature gradient across the plate 606 can provide an indication of the operational status of the uniformity correction system (e.g., operating normally, a faulty coil, cooling failure, etc.). In some embodiments, sensors may be provided in closely spaced pairs to provide redundancy. Each sensor in a pair may be located on either side of a segment of the fluid channel 620. It is contemplated that collecting information from a pair of channels may allow for detection of an error if one sensor fails.

[0079] Terms such as "radiation," "beam," "light," and "illumination" may be used herein to refer to one or more types of electromagnetic radiation, such as ultraviolet (UV) radiation (e.g., having a wavelength λ of 365 nm, 248 nm, 193 nm, 157 nm, or 126 nm), extreme ultraviolet (EUV or soft X-ray) radiation (e.g., having a wavelength in the range of 5 nm to 100 nm, such as 13.5 nm), or hard X-rays operating below 5 nm, as well as particle beams such as ion beams or electron beams. Generally, radiation having wavelengths between about 400 nm and about 700 nm is considered visible radiation, while radiation having wavelengths between about 780 and 3000 nm (or longer) is considered infrared radiation. UV refers to radiation having wavelengths between approximately 100 and 400 nm. In lithography, the term "UV" also applies to wavelengths that can be produced by mercury discharge lamps, namely, G-line at 436 nm, H-line at 405 nm, and I-line at 365 nm. Vacuum ultraviolet (or VUV), i.e., UV absorbed by gases, refers to radiation having a wavelength of approximately 100-200 nm. Deep ultraviolet (DUV) generally refers to radiation having a wavelength in the range of 126 nm to 428 nm, and in some embodiments, excimer lasers can generate DUV radiation for use in lithography equipment. For example, radiation having a wavelength in the range of 5-20 nm should be understood to refer to radiation having a band of wavelengths, at least some of which are in the 5-20 nm range.

[0080] This embodiment can be further described using the following sections. 1. Plate and a plurality of actuators each including a plurality of coils; a plurality of finger structures comprising a beryllium alloy material, each of the plurality of finger structures being coupled to a corresponding one of the plurality of actuators via a magnet, the plurality of finger structures comprising: are independently moved using the plurality of actuators; a light source disposed at least partially within the path of the radiation beam to block at least a portion of said beam; an illumination adjusting device configured to adjust the intensity cross-section of the beam; 2. The lighting adjustment device of clause 1, further comprising a flexure attached to the finger structure, the flexure configured to reduce vibration of the finger structure. 3. The finger structure has a width and a length; the width is less than the length and perpendicular to the length; the finger structure has a lateral vibration mode along the width; 10. The lighting control device of claim 1, wherein the lowest frequency of the lateral vibration mode is about 130 Hz or higher. 4. The plate comprises fluid channels distributed throughout the plate; The lighting adjustment device described in clause 1, wherein the fluid channel is configured to circulate cooling fluid throughout the plate and to introduce the cooling fluid to a central region of the plate before sending the cooling fluid to a peripheral region of the plate. 5. An illumination system configured to illuminate a pattern on a patterning device; A lighting adjustment device, Plate and a plurality of actuators each including a plurality of coils; a plurality of finger structures comprising a beryllium alloy material, each of the plurality of finger structures being coupled to a corresponding one of the plurality of actuators via a magnet, the plurality of finger structures comprising: are independently moved using the plurality of actuators; a light source disposed at least partially within the path of the radiation beam to block at least a portion of said beam; an illumination adjustment device configured to adjust an intensity cross-section of the beam. 6. The lithographic apparatus of clause 5, wherein the illumination adjustment device further comprises a flexure attached to the finger structure, the flexure configured to reduce vibration of the finger structure. 7. The finger structure has a width and a length; the width is less than the length and perpendicular to the length; the finger structure has a lateral vibration mode along the width; 6. The lithographic apparatus of clause 5, wherein the lowest frequency of the lateral vibration mode is about 130 Hz or higher. 8. The plate comprises fluid channels distributed throughout the plate; 6. The lithographic apparatus of clause 5, wherein the fluid channel is configured to circulate a cooling fluid throughout the plate and introduce the cooling fluid to a central region of the plate before sending the cooling fluid to a peripheral region of the plate. 9. A plate comprising fluid channels distributed throughout the plate, the fluid channels configured to circulate a cooling fluid throughout the plate and to introduce the cooling fluid to a central region of the plate before delivering the cooling fluid to a peripheral region of the plate; a plurality of actuators comprising a plurality of coils, wherein at least a portion of the fluid channel is disposed between at least two of the coils; and a plurality of finger structures, each of the plurality of finger structures being coupled to a corresponding one of the plurality of actuators via a magnet, the plurality of finger structures comprising: are independently moved using the plurality of actuators; a light source disposed at least partially within the path of the radiation beam to block at least a portion of said beam; an illumination adjusting device configured to adjust the intensity cross-section of the beam; 10. The fluid channel comprises an inlet and an outlet; 10. The light adjusting device of clause 9, wherein the inlet and the outlet are located on the same side of the plate. 11. The fluid channel comprises an inlet and an outlet; 10. The light adjusting device of clause 9, wherein the inlet and the outlet are located on different sides of the plate. 12. The fluid channel comprises an inlet and an outlet; 10. The lighting adjustment device of clause 9, wherein the inlet and the outlet are located in the same quadrant of the plate. 13. The fluid channel comprises an inlet and an outlet; 10. The light adjusting device of clause 9, wherein the inlet and the outlet are located in different quadrants of the plate. 14. The fluid channel defines a plane; 10. The lighting adjustment device of clause 9, wherein the inlet and / or the outlet are positioned offset from the plane. 15. The lighting adjustment device of clause 9, further comprising a plurality of temperature sensors. 16. The lighting adjustment device of clause 15, wherein at least one of the plurality of temperature sensors is positioned proximate to the central region and another of the plurality of temperature sensors is positioned proximate to the peripheral region. 17. The light conditioning device of clause 9, wherein at least a portion of the fluid channel is configured according to a serpentine structure. 18. The lighting adjustment device of clause 9, wherein the fluid channel is configured such that each of the coils is adjacent to a portion of the fluid channel. 19. The light adjusting device of clause 9, wherein the finger structure comprises a beryllium alloy material. 20. An illumination system configured to illuminate a pattern on a patterning device; A lighting adjustment device, a plate comprising fluid channels distributed throughout the plate, the fluid channels configured to circulate a cooling fluid throughout the plate and to introduce the cooling fluid to a central region of the plate before directing the cooling fluid to a peripheral region of the plate; a plurality of actuators comprising a plurality of coils, wherein at least a portion of the fluid channel is disposed between at least two of the coils; and a plurality of finger structures, each of the plurality of finger structures being coupled to a corresponding one of the plurality of actuators via a magnet, the plurality of finger structures comprising: are independently moved using the plurality of actuators; a light source disposed at least partially within the path of the radiation beam to block at least a portion of said beam; an illumination adjustment device configured to adjust an intensity cross-section of the beam.

[0081] Although some aspects of the present disclosure are described in the context of a lithography apparatus for IC manufacturing, it should be understood that the lithography apparatus described herein may be used in other applications, such as, for example, the manufacture of integrated optical systems, guide and detection patterns for magnetic domain memories, flat panel displays, LCDs, thin-film magnetic heads, etc. Those skilled in the art will recognize that, in these other applications, the terms "wafer" and "die" herein are examples of the more general terms "substrate" and "target portion," respectively. The substrate may be processed, before or after exposure, by, for example, a track unit (a device that typically applies a layer of resist to the substrate and develops the exposed resist) and / or a metrology unit. Where applicable, aspects disclosed herein may also be applied to these or other substrate processing apparatus. Additionally, a substrate may be processed multiple times, for example, to manufacture multi-layer ICs, in which case the term "substrate" herein may refer to a substrate that already includes multiple processed layers.

[0082] Also, while some aspects of the present disclosure are described in the context of optical lithography, it will be understood that aspects of the present disclosure are not limited to optical lithography. For example, in imprint lithography, a topography in a patterning device defines the pattern created on a substrate. The topography of the patterning device is pressed into a layer of resist supplied to the substrate, and the resist is subsequently cured by applying electromagnetic radiation, heat, pressure, or a combination thereof. When the patterning device is moved away from the resist, a pattern is left in the hardened resist.

[0083] The phraseology or terminology used herein is for the purpose of description rather than limitation and should be interpreted by one skilled in the relevant art in light of the teachings herein.

[0084] The disclosure has been described above using functional blocks illustrating the implementation of certain functions and their relationships. The boundaries of these functional blocks have been arbitrarily defined herein for convenience of description. Alternate boundaries may be defined so long as the certain functions and their relationships are appropriately performed. The above description of specific aspects fully discloses the general nature of the disclosure, and thus, by applying the knowledge of those skilled in the art, these specific aspects can be readily modified and / or adapted to various applications without undue experimentation and without departing from the general concept of the disclosure. Therefore, such modifications and adaptations are intended to be within the meaning and range of equivalents of the disclosed aspects, based on the teaching and guidance presented herein.

[0085] It should be appreciated that the "Detailed Description" section, and not the "Summary" and "Abstract" sections, is intended to be used to interpret the claims. While the "Summary" and "Abstract" sections describe one or more aspects of the disclosure contemplated by the inventors, they do not describe every aspect and are therefore not intended to limit the scope of the disclosure and the appended claims in any way. The breadth and scope of the protected subject matter should not be limited by any of the above-described aspects, but should instead be defined according to the appended claims and their equivalents.

Claims

1. Plate and a plurality of actuators each including a plurality of coils; a plurality of finger structures comprising a beryllium alloy material, each of the plurality of finger structures being coupled to a corresponding one of the plurality of actuators via a magnet, the plurality of finger structures comprising: are independently moved using the plurality of actuators; a light source disposed at least partially within the path of the radiation beam to block at least a portion of said beam; an illumination adjusting device configured to adjust the intensity cross-section of the beam;

2. The light adjusting device of claim 1 , further comprising a flexure attached to the finger structure, the flexure configured to reduce vibration of the finger structure.

3. the finger structure has a width and a length; the width is less than the length and perpendicular to the length; the finger structure has a lateral vibration mode along the width; 2. The lighting adjustment device of claim 1, wherein the lowest frequency of the lateral vibration mode is about 130 Hz or higher.

4. the plate comprises fluid channels distributed throughout the plate; 2. The lighting adjustment device of claim 1, wherein the fluid channel is configured to circulate cooling fluid throughout the plate and introduce the cooling fluid to a central region of the plate before sending the cooling fluid to a peripheral region of the plate.

5. an illumination system configured to illuminate a pattern on a patterning device; A lighting adjustment device, Plate and a plurality of actuators each including a plurality of coils; a plurality of finger structures comprising a beryllium alloy material, each of the plurality of finger structures being coupled to a corresponding one of the plurality of actuators via a magnet, the plurality of finger structures comprising: are independently moved using the plurality of actuators; a light source disposed at least partially within the path of the radiation beam to block at least a portion of said beam; an illumination adjustment device configured to adjust an intensity cross-section of the beam.

6. The lithographic apparatus of claim 5 , wherein the illumination conditioning device further comprises a flexure attached to the finger structure, the flexure configured to reduce vibration of the finger structure.

7. the finger structure has a width and a length; the width is less than the length and perpendicular to the length; the finger structure has a lateral vibration mode along the width; The lithographic apparatus of claim 5 , wherein the lowest frequency of the lateral vibration mode is about 130 Hz or higher.

8. the plate comprises fluid channels distributed throughout the plate; 6. The lithographic apparatus of claim 5, wherein the fluid channels are configured to circulate a cooling fluid throughout the plate and to introduce the cooling fluid to a central region of the plate before directing the cooling fluid to a peripheral region of the plate.

9. a plate comprising fluid channels distributed throughout the plate, the fluid channels configured to circulate a cooling fluid throughout the plate and to introduce the cooling fluid to a central region of the plate before directing the cooling fluid to a peripheral region of the plate; a plurality of actuators comprising a plurality of coils, wherein at least a portion of the fluid channel is disposed between at least two of the coils; and a plurality of finger structures, each of the plurality of finger structures being coupled to a corresponding one of the plurality of actuators via a magnet, the plurality of finger structures comprising: are independently moved using the plurality of actuators; a light source disposed at least partially within the path of the radiation beam to block at least a portion of said beam; an illumination adjusting device configured to adjust the intensity cross-section of the beam;

10. the fluid channel comprises an inlet and an outlet; The light adjusting device of claim 9 , wherein the inlet and the outlet are located on the same side of the plate.

11. the fluid channel comprises an inlet and an outlet; The light adjusting device of claim 9 , wherein the inlet and the outlet are located on different sides of the plate.

12. the fluid channel comprises an inlet and an outlet; The light adjusting device of claim 9 , wherein the inlet and the outlet are located in the same quadrant of the plate.

13. the fluid channel comprises an inlet and an outlet; The light adjusting device of claim 9 , wherein the inlet and the outlet are located in different quadrants of the plate.

14. the fluid channel defines a plane; The light adjusting device according to claim 9 , wherein the inlet and / or the outlet are arranged offset from the plane.

15. The light adjusting device of claim 9 , further comprising a plurality of temperature sensors.

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