Movable stage for a lithographic apparatus

Abstract

A lithographic apparatus includes an illumination system, a projection system, and a stage. The illumination system illuminates a pattern of a patterning device. The projection system projects an image of the pattern onto a substrate. The stage moves the patterning device or the substrate. The stage includes a support structure, an actuator device, first, second, and third actuator targets, and a tension member. The third actuator target is attached to a first side of the support structure. The actuator device is disposed proximal to the first and third targets and magnetically interacts with the first and third targets to move the support structure along a direction. The first and second actuator targets are disposed on opposite sides of the support structure and attached to opposite ends of the tension member. The tension member transmits a mechanical load to a second side of the support structure via the second actuator target.

Description

Technical Field

[0001] Cross - reference to Related Applications

[0001] This application claims priority to U.S. Application No. 63 / 341,304, filed May 12, 2022, and U.S. Application No. 63 / 450,877, filed Mar. 8, 2023, which are hereby incorporated by reference in their entirety.

[0002]

[0002] This disclosure relates to a stage, for example a stage for supporting a reticle used in a lithography apparatus and system, during an operation stage.

Background Art

[0003]

[0003] A lithography apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithography apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such a case, a patterning device, also alternatively referred to as a mask or reticle, can be used to generate the circuit patterns formed on the individual layers of the IC. This pattern can be transferred onto a target portion (e.g., including a part of one or several dies) on a substrate (e.g., a silicon wafer). The transfer of the pattern is typically performed by imaging onto a layer of radiation - sensitive material (resist) provided on the substrate. Generally, one substrate includes a network of adjacent target portions to which patterns are sequentially applied. Conventional lithography apparatuses include so - called steppers, in which each target portion is irradiated by exposing the entire pattern onto the target portion in one go, and so - called scanners, in which the pattern is scanned with a radiation beam in a scan direction while the target portion is scanned synchronously in a given direction (the “scan” direction), either parallel or antiparallel to this scan direction, such that each target portion is irradiated. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.

[0004]

[0004] During the lithography operation, different processing steps may require different layers to be sequentially formed on the substrate. Therefore, it may be necessary to position the substrate with respect to a previously formed pattern with high accuracy. Generally, alignment marks are arranged on the substrate to be aligned and positioned with reference to a second object. The lithography apparatus may use an alignment apparatus to detect the position of the alignment marks and to align the substrate using the alignment marks to ensure accurate exposure from the mask. The misalignment between alignment marks in two different layers is measured as an overlay error.

[0005]

[0005] To monitor the lithography process, parameters of the patterned substrate are measured. The parameters may include, for example, overlay errors between successive layers formed within or on the patterned substrate and the critical linewidth of the developed photosensitive resist. This measurement can be performed on the product substrate and / or on a dedicated metrology target. There are various techniques for measuring the fine structures formed in the lithography process, including the use of a scanning electron microscope and various dedicated tools. A fast and non-invasive form of a dedicated inspection tool is a scatterometer that directs a radiation beam onto a target on the substrate surface and measures the characteristics of the scattered or reflected beam. The characteristics of the substrate can be determined by comparing the characteristics of the beam before and after reflection or scattering by the substrate. This can be performed, for example, by comparing the reflected beam with data stored in a library of known measurements related to known substrate characteristics. A spectroscopic scatterometer directs a broadband radiation beam onto the substrate and measures the spectrum of the radiation scattered into a specific narrow angular range (intensity as a function of wavelength). In contrast, an angularly resolved scatterometer uses a monochromatic radiation beam and measures the intensity of the scattered radiation as a function of angle.

[0006]

[0006] Such an optical scatterometer can be used to measure parameters such as the critical dimension of a developed photosensitive resist or the overlay error (OV) between two layers formed within or on a patterned substrate. The characteristics of the substrate can be determined by comparing the characteristics of the illumination beam before and after being reflected or scattered by the substrate.

[0007]

[0007] A lithography system can output only a finite number of fabricated devices within a given time frame. High-speed scanning of the wafer stage and the reticle stage can improve the speed of fabrication. However, high acceleration may distort the stage under mechanical stress.

Summary of the Invention

[0008]

[0008] Therefore, it is desirable to improve the speed of fabrication and throughput. The wafer and reticle stages can be made to withstand high acceleration according to the aspects described herein.

[0009]

[0009] In some embodiments, a lithographic apparatus comprises an illumination system, a projection system, and a stage. The illumination system is configured to illuminate a pattern of a patterning device. The projection system is configured to project an image of the pattern onto a substrate. The stage is configured to move a patterning device or a substrate. The stage comprises a first and a second support structure, an actuator device, an actuator target, and a shaft. The first support structure is configured to support a patterning device or a substrate. The second support structure is configured to support the first support structure. The actuator device is disposed on the second support structure and is configured to move the first support structure along a direction. The actuator target is configured to interact with the actuator device. The shaft is fixed to the actuator target and a location in the first support structure. The shaft is configured to transmit a mechanical load from the actuator target to its location.

[0010]

[0010] In some embodiments, a movable stage comprises a first and a second support structure, an actuator device, an actuator target, and a shaft. The first support structure is configured to support an object. The second support structure is configured to support the first support structure. The actuator device is disposed on the second support structure and is configured to move the first support structure along a direction. The actuator target is configured to interact with the actuator device. The shaft is fixed to the actuator target and a location in the first support structure. The shaft is configured to transmit a mechanical load from the actuator target to its location.

[0011]

[0011] In some embodiments, the lithographic apparatus comprises an illumination system, a projection system, and a stage. The illumination system is configured to illuminate a pattern of a patterning device. The projection system is configured to project an image of the pattern onto a substrate. The stage is configured to move a patterning device or a substrate. The stage comprises a support structure, an actuator device, a tension member, and first, second, and third actuator targets. The support structure is configured to support a patterning device or a substrate. The first actuator target is disposed on a first side of the support structure. The second actuator target is disposed on a second side of the support structure opposite the first side. The third actuator target is attached to the first side of the support structure. The actuator device is disposed proximal to the first and third targets. The actuator device is configured to interact magnetically with the first and third targets to move the support structure along a direction. The first and second actuator targets are attached to opposite ends of the tension member. The tension member is configured to transmit a mechanical load to a second side of the support structure via the second actuator target based on a magnetic force exerted on the first actuator target.

[0012]

[0012] In some embodiments, the stage comprises a support structure, an actuator device, a tension member, and first, second, and third actuator targets. The support structure is configured to support an object. The first actuator target is disposed on a first side of the support structure. The second actuator target is disposed on a second side of the support structure opposite the first side. The third actuator target is attached to the first side of the support structure. The actuator device is disposed proximal to the first and third targets. The actuator device is configured to interact magnetically with the first and third targets to move the support structure along one direction. The first and second actuator targets are attached to opposite ends of the tension member. The tension member is configured to transmit a mechanical load to the second side of the support structure via the second actuator target based on a magnetic force exerted on the first actuator target.

[0013]

[0013] Further features of the present disclosure and the structure and operation of various embodiments will be described in detail below with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to the specific embodiments described herein. Such embodiments are presented herein for illustrative purposes only. Those skilled in the art will readily conceive of further embodiments based on the teachings contained herein.

Brief Description of the Drawings

[0014]

[0014] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and enable those skilled in the art to make and use the embodiments described herein.

[0015]

Figure 1A

[0015] It is a schematic diagram showing a reflective lithography apparatus according to some embodiments.

Figure 1B

[0016] It is a schematic diagram showing a transmissive lithography apparatus according to some embodiments.

Figure 2

[0017] A schematic diagram showing a reflective lithography apparatus according to some embodiments in more detail.

Figure 3

[0018] A schematic diagram showing a lithography cell according to some embodiments.

Figure 4A

[0019] A schematic diagram showing an inspection apparatus according to some embodiments.

Figure 4B

[0019] A schematic diagram showing an inspection apparatus according to some embodiments.

Figure 5

[0020] A diagram showing an operating stage according to some embodiments.

Figure 6

[0020] A diagram showing an operating stage according to some embodiments.

Figure 7A

[0020] A diagram showing an operating stage according to some embodiments.

Figure 7B

[0020] A diagram showing an operating stage according to some embodiments.

Figure 8

[0021] A diagram showing a section of a support structure of a stage according to some embodiments.

Figure 9

[0022] A diagram showing an operating stage according to some embodiments.

Figure 10

[0022] A diagram showing an operating stage according to some embodiments.

[0016]

[0023] The features of the present disclosure will become more apparent by reading the following detailed description with reference to the drawings that identify corresponding elements throughout with like reference numerals. In the drawings, generally, like reference numbers indicate identical, functionally similar, and / or structurally similar elements. Further, generally, the leftmost digit of a reference number identifies the drawing in which the reference number is first shown. Unless otherwise indicated, the drawings provided throughout the present disclosure should not be construed as to-scale drawings.

DETAILED DESCRIPTION OF THE INVENTION

[0017]

[0024] This specification discloses one or more aspects incorporating the features of the present disclosure. The one or more disclosed aspects are provided as examples. The scope of the present disclosure is not limited to the one or more disclosed aspects. The claimed features are defined by the claims appended hereto.

[0018]

[0025] When referring to one or more of the described aspects and in this specification by phrases such as "one aspect", "an aspect", "exemplary aspect", etc., it indicates that the one or more described aspects can include certain features, structures, or characteristics, but each aspect may not necessarily include the certain features, structures, or characteristics. Further, such phrases do not necessarily refer to the same aspect. Further, when describing certain features, structures, or characteristics in relation to an aspect, it is understood that such features, structures, or characteristics can be implemented in relation to other aspects within the knowledge of those skilled in the art, whether explicitly described or not.

[0019]

[0026] Spatially relative terms such as "beneath", "below", "lower", "above", "on", "upper", etc. may be used in this specification to facilitate description of the relationship of one element or feature to another one or more elements or one or more features as shown in the figures. Spatially relative terms are intended to encompass various directions of the device in use or operation in addition to the direction shown in the figures. The device may be oriented in other ways (rotated 90 degrees or in other directions), and the spatially relative descriptors used herein can be interpreted accordingly.

[0020]

[0027] The term "about" as used herein indicates a value of a given quantity that can vary based on a particular technique. Based on the particular technique, the term "about" can indicate, for example, a value of a given quantity that varies within a range of 10 - 30% of that value (e.g., ±10%, ±20%, or ±30% of that value).

[0021]

[0028] Aspects of the present disclosure can be implemented in hardware, firmware, software, or any combination thereof. Aspects of the present disclosure can also be implemented as instructions stored on a machine-readable medium that can be read and executed by one or more processors. A machine-readable medium can include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium can include read only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, electrical, optical, acoustic, or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.), and others. Further, firmware, software, routines, and / or instructions can be described herein as performing certain operations. However, such descriptions are for convenience only, and it will be appreciated that such operations can actually be obtained from a computing device, processor, controller, or other device that executes firmware, software, routines, instructions, etc.

[0022]

[0029] Before detailing such aspects, it may be useful to present an exemplary environment in which aspects of the invention can be implemented.

[0023]

[0030] Exemplary lithography system

[0031] Figures 1A and 1B are schematic views of a lithography apparatus 100 and a lithography apparatus 100', respectively, in which aspects of the present disclosure can be implemented. The lithography apparatus 100 and the lithography 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., a mask table) MT configured to support a patterning device (e.g., a mask, a reticle, or a 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., a 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. The lithography apparatuses 100 and 100' also include a projection system PS configured to project a pattern imparted to the radiation beam B by the patterning device MA onto a target portion C (e.g., including one or more dies) of the substrate W. In the lithography apparatus 100, the patterning device MA and the projection system PS are reflective. In the lithography apparatus 100', the patterning device MA and the projection system PS are transmissive.

[0024]

[0032] The illumination system IL can include various types of optical components, such as refractive, reflective, catadioptric, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof, for directing, shaping, or controlling the radiation beam B.

[0025]

[0033] The support structure MT holds the patterning device MA in a manner that depends on, for example, the orientation of the patterning device MA with respect to a reference frame, the design of at least one of the lithographic apparatuses 100 and 100’, and other conditions such as whether the patterning device is held in a vacuum environment. The support structure MT can hold the patterning device MA using mechanical, vacuum, electrostatic, or other clamping techniques. The support structure MT may be, for example, a frame or a table, and may be fixed or movable as required. By using sensors, the support structure MT can ensure that the patterning device MA comes to a desired position, for example, with respect to the projection system PS.

[0026]

[0034] The term “patterning device” MA should be interpreted broadly to refer to any device that can be used to impart a pattern to a cross-section of the radiation beam B, for example, to generate a pattern in a target portion C of the substrate W. The pattern imparted to the radiation beam B may correspond to a particular functional layer in the device being generated in the target portion C for forming an integrated circuit.

[0027]

[0035] In this specification, terms such as “inspection device”, “metrology system” may be used to refer to a device or system used, for example, to measure characteristics of a structure (e.g., overlay error, critical dimension parameters), or a device or system used within a lithographic apparatus to inspect the alignment of a wafer (e.g., an alignment device).

[0028]

[0036] The patterning device MA may be transmissive (as in the lithographic apparatus 100’ of FIG. 1B) or reflective (as in the lithographic apparatus 100 of 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 masks, Levenson-type phase-shift masks, or halftone-type phase-shift masks, as well as various hybrid mask types. An example of a programmable mirror array employs a matrix array of small mirrors that can be individually tilted so as to reflect an incident radiation beam in different directions. The tilted mirrors impart a pattern to the radiation beam B reflected by the matrix of small mirrors.

[0029]

[0037] The term “projection system” PS includes any type of projection system, suitable for the exposure radiation being used, or other elements such as the use of a liquid immersion fluid or the use of a vacuum on the substrate W, including refractive, reflective, catadioptric, magnetic, electromagnetic, electrostatic optical systems, or any combination thereof. For EUV or electron beam radiation, a vacuum environment may be used since other gases may absorb too much radiation or electrons. Thus, the vacuum environment may be provided throughout the beam path using a vacuum wall and a vacuum pump.

[0030]

[0038] The lithographic apparatus 100 and / or the 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 “multi-stage” machine, additional substrate tables WT may be used in parallel, or preparation steps may be carried out on one or more other tables while one or more substrate tables WT are being used for exposure. In certain situations, the additional table may not be a substrate table WT.

[0031]

[0039] The lithographic apparatus may be of a type adapted to cover at least a portion of a substrate with a liquid having a relatively high refractive index, such as water, so as to fill the space between the projection system and the substrate. The immersion liquid may also be applied to other spaces in the lithographic apparatus, such as, for example, between the mask and the projection system. Immersion techniques are well known in the art for increasing the numerical aperture of the projection system. As used herein, the term "immersion" does not mean that a structure such as a substrate has to be submerged in a liquid, but only that a liquid is present between the projection system and the substrate during exposure.

[0032]

[0040] Referring to FIGS. 1A and 1B, the illuminator IL receives a radiation beam from a radiation source SO. For example, when the radiation source SO is an excimer laser, the radiation source SO and the lithographic apparatuses 100, 100' may be separate physical entities. In this case, the radiation source SO is not considered to form part of the lithographic apparatus 100 or 100', and the radiation beam B travels from the radiation source SO to the illuminator IL via a beam delivery system BD (FIG. 1B) comprising, for example, suitable guiding mirrors and / or a beam expander. In other cases, for example when the radiation source SO is a mercury lamp, the radiation source SO may be an integral part of the lithographic apparatuses 100, 100'. The radiation source SO, the illuminator IL, and also the beam delivery system BD if required, may together be referred to as a radiation system.

[0033]

[0041] The illuminator IL may comprise an adjuster AD (FIG. 1B) for adjusting the angular intensity distribution of the radiation beam. In general, at least the outer and / or inner radial ranges of the intensity distribution in the pupil plane of the illuminator (commonly referred to as "σ-outer" and "σ-inner" respectively) can be adjusted. Further, the illuminator IL may comprise various other components (FIG. 1B) such as an integrator IN and a condenser CO. The illuminator IL can be used to condition the radiation beam B to obtain a desired uniformity and intensity distribution in the beam cross-section.

[0034]

[0042] Referring to Figure 1A, the radiation beam B is incident on a patterning device (e.g., a mask) MA held by a support structure (e.g., a mask table) MT and is patterned by the patterning device MA. In the lithographic apparatus 100, the radiation beam B is reflected from the patterning device (e.g., a mask) MA. After being reflected from the patterning device (e.g., a mask) MA, the radiation beam B passes through the projection system PS. The projection system PS focuses the radiation beam B onto the target portion C of the substrate W. With the help of the second positioner PW and the position sensor IF2 (e.g., an interference device, a linear encoder, or a capacitance sensor), the substrate table WT can be accurately moved (e.g., to position different target portions C in the path of the radiation beam B). Similarly, using the first positioner PM and another position sensor IF1, the patterning device (e.g., a mask) MA can be accurately positioned with respect to the path of the radiation beam B. Mask alignment marks M1, M2 and substrate alignment marks P1, P2 can be used to align the patterning device (e.g., a mask) MA and the substrate W.

[0035]

[0043] Referring to Figure 1B, the radiation beam B is incident on a patterning device (e.g., a mask MA) held by a support structure (e.g., a mask table MT) and is patterned by the patterning device. After traversing the mask MA, the radiation beam B passes through the projection system PS. The projection system PS focuses the beam onto the target portion C of the substrate W. The projection system has a pupil PPU that is conjugate with the illumination system pupil IPU. A part of the radiation originates from the intensity distribution at the illumination system pupil IPU, traverses the mask pattern without being affected by diffraction in the mask pattern, and generates an image of the intensity distribution at the illumination system pupil IPU.

[0036]

[0044] The projection system PS projects an image of the mask pattern MP. The image is formed on a photoresist layer coated on the substrate W by diffracted beams generated from the mask pattern MP by radiation from the intensity distribution. For example, the mask pattern MP may include an array of lines and spaces. From those that are not zero-order diffraction in the radiation diffraction in the array, induced diffracted beams whose directions change in a direction perpendicular to the lines are generated. The non-diffracted beam (i.e., the so-called zero-order diffracted beam) traverses the pattern without changing its propagation direction. The zero-order diffracted beam reaches the conjugate pupil PPU by traversing the upper lens or upper lens group of the projection system PS upstream of the conjugate pupil PPU of the projection system PS. The portion of the intensity distribution on the plane of the conjugate pupil PPU related to the zero-order diffracted beam is an image of the intensity distribution of the illumination system pupil IPU of the illumination system IL. The aperture device PD is arranged, for example, in or substantially in the plane including the conjugate pupil PPU of the projection system PS.

[0037]

[0045] The projection system PS is arranged by the lens or lens group L to capture not only the zero-order diffracted beam but also the first-order or higher-order diffracted beams (not shown). In some embodiments, dipole illumination for imaging a line pattern extending in a direction perpendicular to the lines can be used to utilize the resolution improvement effect of the dipole illumination. For example, the first-order diffracted beam interferes with the corresponding zero-order diffracted beam at the level of the wafer W to generate an image of the line pattern MP with as high a resolution and process window (i.e., a combination of the usable depth of focus and the change in the allowable exposure dose) as possible. In some embodiments, the spherical aberration can be reduced by providing radiation poles (not shown) in the opposite quadrants of the illumination system pupil IPU. Further, in some embodiments, the spherical aberration can be reduced by blocking the zero-order beam in the conjugate pupil PPU of the projection system associated with the radiation poles in the opposite quadrants. This is described in more detail in U.S. Patent No. 7,511,799 issued on March 31, 2009, the entire disclosure of which is incorporated herein by reference.

[0038]

[0046] With the aid of the second positioner PW and the position sensor IFD (e.g., an interference device, a linear encoder, or a capacitance sensor), the substrate table WT can be accurately moved (e.g., to position different target portions C in the path of the radiation beam B). Similarly, with the first positioner PM and another position sensor (not shown in FIG. 1B), the mask MA can be accurately positioned with respect to the path of the radiation beam B (e.g., after mechanical retrieval of the mask library or during scanning).

[0039]

[0047] Generally, the movement of the mask table MT can be realized with the aid of a long-stroke module (coarse positioning) and a short-stroke module (fine positioning) that form part of the first positioner PM. Similarly, the movement of the substrate table WT can be realized using a long-stroke module and a short-stroke module that 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 or fixed to only the short-stroke actuator. The mask MA and the substrate W can be aligned using the mask alignment marks M1, M2 and the substrate alignment marks P1, P2. The substrate alignment marks (as shown) occupy dedicated target portions, but may also be located in the space between the target portions (well-known as scribe line alignment marks). Similarly, in a situation where a plurality of dies are provided on the mask MA, the mask alignment marks may be arranged between the dies.

[0040]

[0048] The mask table MT and the patterning device MA may be within the vacuum chamber V. Using an in-vacuum robot IVR, patterning devices such as masks can be moved into and out of the vacuum chamber. Alternatively, if the mask table MT and the patterning device MA are outside the vacuum chamber, an out-of-vacuum robot can be used for various transportation operations, similar to the in-vacuum robot IVR. Both the in-vacuum and out-of-vacuum robots need to be calibrated for the smooth transfer of any payload (e.g., a mask) to a fixed kinematic mount of the relay station.

[0041]

[0049] The lithographic apparatuses 100 and 100’ can be used in at least one of the following modes.

[0042]

[0050] 1. In the step mode, the support structure (e.g., the mask table) MT and the substrate table WT are basically maintained in a stationary state, while the entire pattern imparted to the radiation beam B is projected onto the target portion C in one go (i.e., single static exposure). Next, the substrate table WT is shifted in the X direction and / or the Y direction so that another target portion C can be exposed.

[0043]

[0051] 2. In the scan mode, the support structure (e.g., the mask table) MT and the substrate table WT are scanned synchronously, while the pattern imparted to the radiation beam B is projected onto the target portion C (i.e., single dynamic exposure). The speed and direction of the substrate table WT relative to the support structure (e.g., the mask table) MT can be determined by the magnification (reduction) and image inversion characteristics of the projection system PS.

[0044]

[0052] 3. In another mode, the support structure (e.g., mask table) MT holds the programmable patterning device and is essentially maintained in a stationary state while the substrate table WT is moved or scanned and the pattern imparted to the radiation beam B is projected onto the target portion C. A pulsed radiation source SO can be used and the programmable patterning device is updated as required each time the substrate table WT is moved or between successive radiation pulses during the scan. This mode of operation can be readily applied to maskless lithography utilizing a programmable patterning device such as a programmable mirror array.

[0045]

[0053] Combinations and / or variations of the usage modes described above, or entirely different usage modes, can also be utilized.

[0046]

[0054] In a further aspect, the lithographic apparatus 100 comprises an extreme ultraviolet (EUV) radiation source. The extreme ultraviolet radiation source is configured to generate an EUV radiation beam for EUV lithography. Generally, the EUV radiation source is configured within a radiation system and the corresponding illumination system is configured to condition the EUV radiation beam of the EUV radiation source.

[0047]

[0055] Figure 2 shows lithographic apparatus 100 in more detail, which comprises 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 within a closed structure 220 of the source collector apparatus SO. An EUV radiation emitting plasma 210 can be formed by a discharge generating plasma source. To generate EUV radiation, for example, a very high temperature plasma 210 may be generated by a gas or vapor such as Xe gas, Li vapor, or Sn vapor, and radiation within the EUV range of the electromagnetic spectrum may be emitted. The very high temperature plasma 210 is generated, for example, by causing at least an imperfectly ionized plasma by means of a discharge. For efficient radiation generation, for example, Xe, Li, Sn vapor with a partial pressure of 10 Pa or any other suitable gas or vapor may be required. In some embodiments, an excited tin (Sn) plasma is supplied to generate EUV radiation.

[0048]

[0056] The radiation emitted by the high temperature plasma 210 is sent from the radiation source chamber 211 into the collector chamber 212 via an optional gas barrier or contaminant trap 230 (sometimes also called a contaminant barrier or foil trap) positioned within or behind the opening of the radiation source chamber 211. The contaminant trap 230 can include a channel structure. The contaminant trap 230 can also include a gas barrier or a combination of a gas barrier and a channel structure. The contaminant trap or contaminant barrier 230 further shown herein includes at least a channel structure.

[0049]

[0057] The collector chamber 212 can include a radiation collector CO, which can also be a so-called graze-incidence collector. The radiation collector CO has an upstream radiation collector side 251 and a downstream radiation collector side 252. Radiation traversing the collector CO can be reflected by the grating spectral filter 240 and focused onto a virtual light source point INTF. The virtual light source point INTF is generally called an intermediate focus, and the source collector apparatus is arranged such that the intermediate focus INTF is located at or near the aperture 219 of the closed structure 220. The virtual light source point INTF is an image of the radiation-emitting plasma 210. The grating spectral filter 240 is used particularly for suppressing infrared (IR) radiation.

[0050]

[0058] Thereafter, the radiation traverses the illumination system IL. The illumination system IL can comprise a facet field mirror device 222 and a facet pupil mirror device 224 arranged to provide a desired angular distribution of the radiation beam 221 and a desired radiation intensity uniformity in the patterning device MA. When the radiation beam 221 is reflected in the patterning device MA held by the support structure MT, a patterned beam 226 is formed, and the patterned beam 226 is imaged onto a substrate W held by a wafer stage or a substrate table WT by a projection system PS via reflection elements 228, 229.

[0051]

[0059] In general, the illumination optical unit IL and the projection system PS can have more elements than shown. The grating spectral filter 240 can be optionally present depending on the type of lithographic apparatus. Further, there can be more mirrors than shown in FIG. 2, for example, the projection system PS can have from one to six additional reflection elements than shown in FIG. 2.

[0052]

[0060] As shown in FIG. 2, collector system CO is shown as a nested collector having grazing incidence reflectors 253, 254, and 255 as just one example of a collector (or collector mirror). The grazing incidence reflectors 253, 254, and 255 are arranged axially symmetrically about the optical axis O, and this type of collector system CO is preferably used in combination with a discharge generating plasma source, often called a DPP source.

[0053]

[0061] Exemplary lithography cell

[0062] FIG. 3 shows a lithography cell 300, sometimes called a litho cell or cluster, according to some aspects. The lithography apparatus 100 or 100' can form part of the lithography cell 300. The lithography cell 300 can also include one or more devices that perform 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 the exposed resist, a cooling plate CH, and a bake plate BK. A substrate handler, i.e., a robot RO, retrieves substrates from the input / output ports I / O1, I / O2, moves them between the various process devices, and delivers them to the loading bay LB of the lithography apparatus 100 or 100'. These devices are often collectively called a track and are under the control of a track control unit TCU. The TCU itself is controlled by a monitoring control system SCS, which also controls the lithography apparatus via a lithography control unit LACU. Thus, these various devices can be operated to maximize throughput and processing efficiency.

[0054]

[0063] Exemplary inspection apparatus

[0064] To control a lithography process for accurately placing device features on a substrate, alignment marks are generally provided on the substrate, and the lithography apparatus includes one or more inspection devices for accurately positioning the marks on the substrate. These alignment devices are effective position measuring devices. Various types of marks and various types of alignment devices and / or systems are known from various times and various manufacturers. A type of system widely used in current lithography apparatuses is based on a self-referencing interferometer as described in U.S. Patent No. 6,961,116 (den Boef et al.). Generally, marks are measured separately to obtain X and Y positions. However, combined X and Y measurements can be performed using the techniques described in U.S. Patent Publication No. 2009 / 195768 (BiJnen et al.). The entire contents of both of these disclosures are incorporated herein by reference.

[0055]

[0065] FIG. 4A is a schematic view showing a cross-sectional view of an inspection device 400 that can be implemented as part of a lithography apparatus 100 or 100' according to some aspects. In some aspects, the inspection device 400 can be configured to align a substrate (e.g., substrate W) with respect to a patterning device (e.g., patterning device MA). The inspection device 400 can be further configured to detect the position of an alignment mark on the substrate and to align the substrate with respect to a patterning device or other components of the lithography apparatus 100 or 100' using the detected position of the alignment mark. Such alignment of the substrate can ensure accurate exposure of one or more patterns on the substrate.

[0056]

[0066] In some embodiments, inspection apparatus 400 can include an illumination system 412, a beam splitter 414, an interferometer 426, a detector 428, a beam analyzer 430, and an overlay calculation processor 432. The illumination system 412 can be configured to provide an electromagnetic narrowband radiation beam 413 having one or more passbands. In one example, the one or more passbands can be within a spectrum of wavelengths between about 500 nm and about 900 nm. In another example, the one or more passbands can be discrete narrow passbands within a spectrum of wavelengths between about 500 nm and about 900 nm. The illumination system 412 can be further configured to provide one or more passbands having a substantially constant center wavelength (CWL) value over a long time period (e.g., over the lifetime of the illumination system 412). Such a configuration of the illumination system 412 can be useful in preventing a shift of the actual CWL value from the desired CWL value in current alignment systems, as discussed above. Also as a result, the use of a constant CWL value can improve the long-term stability and accuracy of the alignment system (e.g., inspection apparatus 400) compared to current alignment devices.

[0057]

[0067] In some embodiments, beam splitter 414 is configurable to receive radiation beam 413 and split radiation beam 413 into at least two radiation sub - beams. For example, radiation beam 413 can be split into radiation sub - beams 415 and 417 as shown in FIG. 4A. Beam splitter 414 is further configurable to direct radiation sub - beam 415 onto substrate 420 disposed on stage 422. In one example, stage 422 is movable along direction 424. Radiation sub - beam 415 is configurable to illuminate an alignment mark or target 418 disposed on substrate 420. Alignment mark or target 418 can be coated with a radiation - sensitive film. In some embodiments, alignment mark or target 418 can have 180 - degree (i.e., 180°) symmetry. That is, when alignment mark or target 418 is rotated 180° about an axis of symmetry perpendicular to the plane of alignment mark or target 418, the rotated alignment mark or target 418 can be substantially identical to the non - rotated alignment mark or target 418. Target 418 on substrate 420 can be a composite grating stack in an overlay target structure comprising (a) a resist layer grating including bars formed from real resist lines, or (b) a product layer grating, or (c) a resist grating overlaid or interleaved on a product layer grating. The bars can alternatively be etched into the substrate. This pattern is sensitive to chromatic aberration in a lithographic projection apparatus, particularly in projection system PL, and the illumination symmetry and the presence of such aberrations will manifest themselves in variations in the printed grating. One in - line method used in device manufacturing for the measurement of linewidth, pitch, and critical dimensions utilizes a technique called "scatterometry". The scatterometry method is described in "Multiparameter Grating Metrology Using Optical Scatterometry" by Raymond et al., J. Vac. Sci. Tech. B, Vol. 15, no. 2, pp.It is described in 361 - 368(1997) and "Specular Spectroscopic Scatterometry in DUV Lithography" by Niu et al., SPIE, Vol. 3677(1999), and the entireties of both are incorporated herein by reference. In scatterometry, light is reflected by a periodic structure within a target, and the resulting reflection spectrum at a given angle is detected. The structure that causes the reflection spectrum is reconstructed, for example, by using Rigorous Coupled - Wave Analysis (RCWA) or by comparing with a library of patterns derived by simulation. Thus, the scatterometry data of a printed grating is used to reconstruct the grating. Parameters of the grating such as line width and shape can be input into a reconstruction process executed by a processing unit PU from knowledge of the printing step and / or other scatterometry processes.

[0058]

[0068] In some embodiments, the beam splitter 414 can be further configured to receive the diffracted radiation beam 419 and split the diffracted radiation beam 419 into at least two radiation sub - beams according to one embodiment. The diffracted radiation beam 419 can be split into diffracted radiation sub - beams 429 and 439 as shown in FIG. 4A.

[0059]

[0069] Note that even if the beam splitter 414 is shown to direct the radiation sub - beam 415 towards the alignment mark or target 418 and direct the diffracted radiation sub - beam 429 towards the interferometer 426, the present disclosure is not so limited. It will be apparent to those skilled in the art that other optical arrangements can be used to illuminate the alignment mark or target 418 on the substrate 420 and obtain similar results to detecting an image of the alignment mark or target 418.

[0060]

[0070] As shown in FIG. 4A, the interferometer 426 can be configured to receive a radiation sub-beam 417 and a diffracted radiation sub-beam 429 via a beam splitter 414. In an exemplary embodiment, the diffracted radiation sub-beam 429 can be at least a part of the radiation sub-beam 415 that can be reflected from an alignment mark or target 418. In an example of this embodiment, the interferometer 426 comprises a set of any suitable optical elements, for example, a combination of prisms that can be configured to form two images of the alignment mark or target 418 based on the received diffracted radiation sub-beam 429. It should be understood that a good quality image need not be formed, but the features of the alignment mark 418 should be resolved. The interferometer 426 can be further configured to rotate one of the two images by 180° with respect to the other of the two images and recombine the rotated image and the non-rotated image interferometrically.

[0061]

[0071] In some embodiments, the detector 428 is configured to receive the recombined image via the interferometer signal 427 and detect interference as a result of the recombined image when the alignment axis 421 of the inspection apparatus 400 passes through the center of symmetry (not shown) of the alignment mark or target 418. Such interference may be due to, according to the exemplary embodiment, the alignment mark or target 418 being 180° symmetric and the recombined images interfering constructively or destructively. Based on the detected interference, the detector 428 can be further configured to determine the position of the center of symmetry of the alignment mark or target 418 and, as a result, detect the position of the substrate 420. According to an example, the alignment axis 421 can be aligned with an optical beam that is perpendicular to the substrate 420 and passes through the center of the image rotation interferometer 426. The detector 428 can be further configured to estimate the position of the alignment mark or target 418 by implementing sensor features and interacting with wafer mark process variations.

[0062]

[0072] In a further aspect, detector 428 determines the position of the center of symmetry of alignment mark or target 418 by performing one or more of the following measurements. 1. Measuring position variations (position shifts between colors) for various wavelengths, 2. Measuring position variations (position shifts between diffraction orders) for various orders, and, 3. Measuring position variations (position shifts between polarities) for various polarities.

[0063]

[0073] This data can be obtained using a SMASH (SMart Alignment Sensor Hybrid) sensor as described in U.S. Patent No. 6,961,116, which employs any type of alignment sensor, e.g., a single detector and a self-referencing interferometer with four different wavelengths, and extracts the alignment signal in software, or an Athena (Advanced Technology using High order ENhancement of Alignment) as described in U.S. Patent No. 6,297,876, which directs each of seven diffraction orders to a dedicated detector, the entirety of both being incorporated herein by reference.

[0064]

[0074] In some embodiments, the beam analyzer 430 can be configured to receive and determine the optical state of the diffracted radiation sub-beam 439. The optical state can be a measurement of the beam wavelength, polarity, or beam profile. The beam analyzer 430 can be further configured to determine the position of the stage 422 and correlate the position of the stage 422 with the position of the center of symmetry of the alignment mark or target 418. Thus, the position of the alignment mark or target 418 and, as a result, the position of the substrate 420 can be accurately known relative to the stage 422. Alternatively, the beam analyzer 430 can be configured to determine the position of the inspection apparatus 400 or any other reference element so that the center of symmetry of the alignment mark or target 418 can be known with reference to the inspection apparatus 400 or any other reference element. The beam analyzer 430 can be a point or imaging polarimeter with some form of wavelength band selectivity. In some embodiments, the beam analyzer 430 can be directly integrated within the inspection apparatus 400 or, according to other embodiments, can be connected via some types of optical fibers such as polarization-maintaining single-mode, multi-mode, or imaging.

[0065]

[0075] In some embodiments, beam analyzer 430 can be further configured to determine overlay data between two patterns on substrate 420. One of these patterns can be a reference pattern on a reference layer. The other pattern can be an exposure pattern on an exposure layer. The reference layer can be an etching layer already present on substrate 420. The reference layer can be generated by a reference pattern exposed on the substrate by lithography apparatus 100 and / or 100'. The exposure layer can be a resist layer exposed proximate to the reference layer. The exposure layer can be generated by an exposure pattern exposed on substrate 420 by lithography apparatus 100 or 100'. The exposure pattern on substrate 420 can correspond to the movement of substrate 420 by stage 422. In some embodiments, the measured overlay data can also indicate an offset between the reference pattern and the exposure pattern. The measured overlay data can be used as calibration data to calibrate the exposure pattern exposed by lithography apparatus 100 or 100', and after calibration, the offset between the exposure layer and the reference layer can be minimized.

[0066]

[0076] In some embodiments, the beam analyzer 430 can be further configured to determine a model of the product stack profile of the substrate 420 and can be configured to measure the overlay, critical dimensions, and focus of the target 418 in a single measurement. The product stack profile includes information about stacked products such as alignment marks, the target 418, or the substrate 420 and can include mark process variation induced optical signature metrology that is a function of illumination variation. The product stack profile can also include a product grating profile, a mark stack profile, and mark asymmetry above. An example of the beam analyzer 430 is a Yieldstar™ manufactured by ASML of Veldhoven, the Netherlands, as described in U.S. Patent No. 8,706,442, which is hereby incorporated by reference in its entirety. The beam analyzer 430 can be further configured to process information regarding specific characteristics of the exposed pattern within the layer. For example, the beam analyzer 430 can process overlay parameters (an indication of the layer positioning accuracy with respect to the previous layer on the substrate or the first layer positioning accuracy with respect to a mark on the substrate), focus parameters, and / or critical dimension parameters of the image shown within the layer (e.g., line width and its variation). Other parameters are image parameters regarding the quality of the shown image of the exposed pattern.

[0067]

[0077] In some embodiments, an array of detectors (not shown) can be connected to the beam analyzer 430, allowing for the possibility of accurate stack profile detection, as discussed below. For example, detector 428 can be an array of detectors. In the case of a detector array, several options are possible, such as a bundle of multimode fibers, discrete PIN detectors per channel, or a CCD or CMOS (linear) array. The use of a bundle of multimode fibers allows any dissipative elements to be placed remotely for stability. Discrete PIN detectors provide a large dynamic range but require a separate preamplifier for each one. Therefore, the number of elements is limited. CCD linear arrays are fast readable and provide a large number of elements of particular interest when phase stepping detection is used.

[0068]

[0078] In some embodiments, the second beam analyzer 430' can be configured to receive and determine the optical state of the diffracted radiation sub-beam 429 as shown in FIG. 4B. The optical state can be a measurement of the beam wavelength, polarity, or beam profile. The second beam analyzer 430' can be identical to the beam analyzer 430. Alternatively, the second beam analyzer 430' can be configured to perform at least all of the functions of the beam analyzer 430, such as determining the position of the stage 422 and correlating the position of the stage 422 with the position of the center of symmetry of the alignment mark or target 418. Thus, the position of the alignment mark or target 418 and, as a result, the position of the substrate 420 can be accurately known while referring to the stage 422. The second beam analyzer 430' can also be configured to determine the position of the inspection device 400 or any other reference element so that the center of symmetry of the alignment mark or target 418 can be known with reference to the inspection device 400 or any other reference element. The second beam analyzer 430' can be further configured to determine the overlay data between two patterns and the model of the product stack profile of the substrate 420. The second beam analyzer 430' can also be configured to measure the overlay, critical dimension, and focus of the target 418 in a single measurement.

[0069]

[0079] In some embodiments, the second beam analyzer 430' can be directly integrated within the inspection device 400 or, according to other embodiments, can be connected via some types of optical fibers such as polarization-maintaining single-mode, multi-mode, or imaging. Alternatively, the second beam analyzer 430' and the beam analyzer 430 can be combined to form a single analyzer (not shown) configured to receive and determine the optical states of both the diffracted radiation sub-beams 429 and 439.

[0070]

[0080] In some embodiments, processor 432 receives information from detector 428 and beam analyzer 430. For example, processor 432 can be an overlay calculation processor. The information can include a model of a product stack profile constructed by beam analyzer 430. Alternatively, processor 432 can construct a model of a product mark profile using the received information regarding the product mark. In either case, processor 432 constructs a model of the stacked product and overlay mark profile that uses or incorporates the model of the product mark profile. The stack model is then used to determine an overlay offset and minimize the spectral effects on the overlay offset measurement. Processor 432 can create a basic correction algorithm based on information received from detector 428 and beam analyzer 430, including but not limited to the optical state of the illumination beam, alignment signals, associated position estimates, and the optical states in the pupil, image, and additional planes. The pupil plane is a plane in which the emission position of the radiation defines an angle of incidence and the angular position defines the azimuth angle of the radiation. Processor 432 can utilize the basic correction algorithm to characterize inspection apparatus 400 with respect to wafer mark and / or alignment mark 418.

[0071]

[0081] In some embodiments, the processor 432 can be further configured to determine a print pattern position offset error for a sensor estimate for each mark based on information received from the detector 428 and the beam analyzer 430. The information includes, but is not limited to, the product stack profile, overlay measurements, critical dimensions, and the focus of each alignment mark or target 418 on the substrate 420. The processor 432 can utilize a clustering algorithm to group the marks into sets of similar constant offset errors and create an alignment error offset correction table based on the information. The clustering algorithm can be based on overlay measurements, position estimates, and additional optical stack process information associated with each set of offset errors. The overlay is calculated for different numbers of marks, such as an overlay target having positive and negative biases around a programmed overlay offset. The target that measures the smallest overlay is adopted as a reference (as being measured with the best accuracy). The overlay error can be inferred from this measured smallest overlay and the known programmed overlay of the corresponding target. Table 1 shows how this can be done. The smallest measured overlay in the example shown is -1 nm. However, this is for a target with a programmed overlay of -30 nm. The process can result in an overlay error of 29 nm.

[0072]

Table 1

[0073]

[0082] The minimum value can be adopted as a reference point, and in this regard, the offset between the measured overlay and the predicted overlay due to the programmed overlay can be calculated. This offset determines the overlay error for each mark or a set of marks with similar offsets. Thus, in the example of Table 1, the minimum measured overlay at the target position with a programmed overlay of 30 nm was -1 nm. The difference between the predicted and measured overlays at other targets is compared to this reference. Tables such as Table 1 can also be obtained from marks and targets 418 under different illumination settings, and it is possible to determine and select the illumination setting that results in the minimum overlay error and the corresponding calibration factor. Subsequently, the processor 432 can group the marks into sets of similar overlays. The criteria for grouping the marks can be adjusted based on various process controls, such as various error tolerances for various processes.

[0074]

[0083] In some aspects, the processor 432 can recognize that all or most members of a group have similar offset errors and apply individual offset corrections to each mark from a clustering algorithm based on additional optical stack metrology. The processor 432 can determine the correction for each mark and feedback the correction to the lithography apparatus 100 or 100' by, for example, feeding the correction into the inspection apparatus 400 to correct the error in the overlay.

[0075]

[0084] Exemplary operating stages

[0085] In some aspects, the term "throughput" can be used to describe the rate at which wafers clear a particular fabrication step and move to the next step. Throughput can be a marketable performance marker for a lithography system. In a lithography system, it is desirable to output as many products as possible in as short a time as possible. Lithography fabrication can include several complex fabrication processes. Each fabrication process has technical characteristics that maintain a balance between desired product quality and drawbacks (e.g., low-speed fabrication, printing errors, cost, etc. versus sub-nanometer accuracy, high yield per wafer, high throughput, etc.).

[0076]

[0086] In a lithography apparatus (or inspection apparatus), a wafer or reticle can be scanned at a given speed in a given direction. The wafer and reticle can be supported on a chuck on a high-acceleration stage. However, forces from high acceleration can potentially distort (e.g., elongate) the chuck, which can cause positioning errors in the wafer or reticle. Positioning errors can cause printing errors in devices manufactured from the wafer.

[0077]

[0087] Aspects disclosed herein include devices and functions for addressing structural problems of a movable stage with very little concession in terms of space requirements, complexity, and cost.

[0078]

[0088] Figure 5 shows a stage 500 for supporting an object 502 according to some embodiments. In some embodiments, the stage 500 can include a support structure 504 (e.g., a first support structure), a support structure 506 (e.g., a second support structure), an actuator device 510, and an actuator target 508. The actuator device 510 can include a coil winding 512. The actuator target 508 can be disposed and fixed on the support structure 504 using a fixing structure 514 (e.g., epoxy). The number and configuration of the actuator-related elements are not limited to those shown in Figure 5. Fewer or more actuator-related elements, and other configurations can be used. The stage 500 can also include one or more position indicators 516 (e.g., an encoder scale).

[0079]

[0089] In some embodiments, it should be understood that ordinal adjectives (e.g., "first", "second", "third", etc.) can be used as a naming convention and are not intended to indicate an order or hierarchy (unless otherwise specified). For example, the terms "first support structure" and "second support structure" can distinguish two support structures, but it is not necessary to specify whether the support structures have a particular order or hierarchy. Further, the elements in the drawings are not limited to any particular ordinal adjectives. For example, one actuator device 510 can be called a second actuator device if the other actuator device uses ordinal adjectives to appropriately distinguish. In another non-limiting example, it can be selected to name the upper right actuator device 510 as the first actuator device, and then the remaining actuator devices can be identified as second, third, and fourth in order, such as clockwise, counterclockwise, cross pattern, etc.

[0080]

[0090] In some embodiments, stage 500 can be used in a lithographic apparatus 100 or 100' (Figs. 1A, 1B, and 2), a lithography cell 300 (Fig. 3), an inspection apparatus 400 (Figs. 4A and 4B), or any apparatus generally having a stage implementation for supporting and moving an object. For example, stage 500 can represent a particular implementation of a wafer table WT or a mask table MT (Figs. 1A, 1B, and 2), or stage 422 (Figs. 4A and 4B).

[0081]

[0091] In some embodiments, support structure 506 can be an actuation structure (e.g., for coarse movement of object 502). In a lithographic manufacturing process, object 502 can be, for example, a semiconductor wafer having a diameter of 300 mm (which is a non-limiting example of a wafer commercially available in different sizes, as would be understood by one of ordinary skill in the art). Further, stage 500 can also include an additional movement budget for shuttling object 502 between a loading area. Thus, support structure 506 can be responsible for coarse movement of stage 500, for example, on the order of tens, hundreds, or thousands of millimeters. Other distances can be selected based on the compatibility for a particular implementation. However, in an implementation where coarse movement is not required, support structure 506 can be a static frame.

[0082]

[0092] In some embodiments, the support structure 504 can be supported by the support structure 506 while also allowing relative movement between the two support structures. The movement of the support structure 504 can be limited to an axis (e.g., the Y-axis) using a guide rail or a non-contact method (e.g., magnetic levitation) (the guide device is not shown). The actuator device 510 can be responsible for fine-tuning the position of the support structure 504. Thus, some embodiments use a small gap between the actuator device 510 and their corresponding actuator target 508. For example, the gap can be less than a few millimeters (e.g., less than approximately 1 mm). In a scanning lithography process, the printed device can have critical dimensions within the sub-micron or sub-nanometer range. A 1-millimeter movement budget can be large enough for scanning printing of sub-nanometer devices.

[0083]

[0093] In some embodiments, the actuator device 510 can be disposed and fixed on the support structure 506. The actuator device 510 can operate the support structure 504 by interacting with the actuator target 508. The actuator target 508 can comprise a material that reacts to a magnetic field (e.g., metal, iron, ferrite, etc.). The actuator device 510 can be an electromagnet. The electromagnet can generate and adjust a magnetic field. The electromagnet can comprise a coil 512 of wire wound around a metal core (e.g., a ferrite core). The actuator device 510 can be operable to only attract when the actuator target 508 is not a permanent magnet. Conversely, the actuator device 510 can be capable of repelling and attracting a permanent magnet version of the actuator target 508 by reversing the direction of the magnetic field. The actuator setup described herein can be referred to by other technical terms. (e.g., reluctance actuator. Thus, the actuator target 508 can be called a reluctance target.)

[0084]

[0094] In some embodiments, the actuator device 510 can operate the support structure 504 using high acceleration. The acceleration can be, for example, approximately 4 - 100 g, 10 - 50 g, 20 - 40 g, etc. (where g is 9.8 m / s 2 ^2^). The high acceleration can improve lithographic printing production (e.g., improve throughput). Lithographic pattern transfer can be performed when the support structure 504 is in motion, for example, when a certain coasting speed is reached. The coasting speed can be, for example, 0.5 - 10.0 m / s, 1.0 - 7.0 m / s, 3.0 - 5.0 m / s, etc. Performing pattern transfer at a constant scanning speed can result in a more accurate transfer of the printed pattern, while printing during acceleration can be associated with greater positional uncertainty.

[0085]

[0095] In some embodiments, the nature of the magnetic field is such that the repulsive interaction is unstable and can generate unwanted lateral forces (orthogonal to the direction of repulsion) and unwanted orthogonal torques. The orthogonal force / torque tends to move the magnets to change the interaction from repulsive to attractive in order to minimize the total potential energy of the magnet set. Without an external lateral guiding or restraining force, the arrangement is unstable and jumps to the nearest stable equilibrium position while closing the gap (no longer floating). Thus, a repulsive system using permanent magnets can be difficult for an engineer and can prompt the addition of active control or an external mechanical guide to prevent the arrangement from collapsing. Adding the complexity of a lithographic system can significantly increase the engineering difficulty. Thus, in some embodiments, the actuator device 510 can be designed to operate using only attraction (or only pull). Having the actuator device 510 on the opposite side of the support structure 504 makes it possible to transmit both forward and backward motion to the support structure 504 while using only a pull configuration. However, the pull - only method can have certain drawbacks, as will be considered in more detail below.

[0086]

[0096] In some embodiments, the object 502 can be temporarily fixed on the support structure 504 by pressing the object 502 onto the support structure 504. This can be achieved by a vacuum clamp (suction force), an electrostatic clamp (electrostatic force), a mechanical clamp, etc. Under ideal conditions, the mutual friction between the object 502 (e.g., a reticle) and the support structure 504 (e.g., a chuck) can ensure that there is no slippage between them. However, the mechanical stress caused by high acceleration may induce some slippage, resulting in printing errors. The errors can be quite harmful due to the possibility of losses of thousands of device products over the time when the errors can be detected.

[0087]

[0097] The following is an example of a positioning error of the object 502 when using the stage 500. In some embodiments, the object 502 can be fixed on the support structure 504. To determine the position of the features on the object 502, for example, a calibration measurement can be performed using an optical inspection system. The calibration measurement can determine the position of the features on the object 502 relative to one or more position indicators 516. The position indicators 516 can be firmly fixed to the support structure 504. Once the relationship between the object 502 and the one or more position indicators 516 is established, the object 502 can be used in a high-precision process (e.g., a lithography process), and as long as the object 502 remains stationary relative to the support structure 504, there is no need to perform calibration. Conversely, any relative movement between the object 502 and the support structure 504 may be regarded as a positioning error, i.e., an error that is subsequently transmitted to any process after the occurrence of an error event.

[0088]

[0098] The following is an example of conditions and mechanisms that can induce positioning errors. In some embodiments, an electromagnetic force can be applied to actuator target 508 by actuator device 510. For example, actuator device 510 on the left side of support structure 504 can be activated, and then the corresponding actuator 508, fixed structure 514, and ultimately support structure 504 can be pulled. As a result, actuator device 510 on the right side of support structure 504 can be used to pull in the opposite direction (for deceleration) and to keep support structure 504 stationary. During acceleration / deceleration, the combined mass of object 502 and support structure 504 has inertia and exerts an opposing force equal to the force exerted by actuator target 508 during the pull (depicted as an arrow "ma" (mass × acceleration) pointing to the right). Conversely, when two actuator targets 508 are performing a pull, the pulling force can be divided between the two actuator targets 508 (depicted as two arrows "F = ma / 2").

[0089]

[0099] A drawback of the pull-only method is that in some embodiments, support structure 504 can be under a high-tension gradient due to high acceleration (e.g., 4 to 100 g). The tension can potentially deform (e.g., stretch) support structure 504. Even if support structure 504 is made of a rigid structure (e.g., made of glass and rib reinforcements), even a deformation of a few picometers can shift object 502 by a few picometers with respect to one or more position indicators 516, thereby causing a positioning error. The pull-push method (where some actuator devices 510 pull and some push from behind) counteracts many of the tension and deformation problems but can also introduce the aforementioned problems related to magnetic repulsion.

[0090]

[0100] Another disadvantage of the pull-only method is that in some embodiments, the fixed structure 514 can also be under significant tension due to high acceleration. In a non-limiting example where the fixed structure 514 is made of epoxy, epoxy under tension only may creep (e.g., slowly spread over time), increasing the likelihood of mechanical failure compared to the pull-push method where the average epoxy stress is zero (e.g., it is under tension in the case of a one-way pull but also under compression in the case of a push in the opposite direction).

[0091]

[0101] Some embodiments described herein provide structures and functions to address problems of the pull-only method.

[0092]

[0102] FIG. 6 shows a stage 600 for supporting an object 602 according to some embodiments. In some embodiments, the stage 600 can have some of the features already described with reference to FIG. 5. Compared to FIG. 6, some elements may be non-displayed (for clarity) but additional elements may be shown. Unless otherwise stated, the structures and functions previously described for the elements of FIG. 5 are also applicable to the similarly numbered (e.g., the reference numbers share the rightmost two digits) elements of FIG. 6. The structures and functions of at least some of the elements of FIG. 6 are apparent from the description of the corresponding elements of FIG. 5 and will not be reintroduced.

[0093]

[0103] In some embodiments, in addition to the features of stage 500 (FIG. 5), stage 600 can also include additional internal actuator devices 610i and an extension structure 618 (e.g., a cantilever). Similar to actuator device 610, internal actuator device 610i can be disposed and fixed on support structure 606. Using extension structure 618, actuator target 608 can be structurally fixed away from the side of support structure 604 by utilizing a fixed structure 614 (e.g., epoxy). When space is created by extension structure 618, a given one of internal actuator devices 610i can be disposed within the internal space defined by its corresponding actuator target 608, its corresponding extension structure 618, and the side of support structure 604 (as shown in FIG. 6).

[0094]

[0104] In some embodiments, the configuration of stage 600 can be used to overcome at least some of the problems described above for stage 500 (FIG. 6). For example, the two left actuator devices 610 are for pulling support structure 604, while two other internal actuator devices 610i on the right side of support structure 604 can be used to "push" support structure 604. The four activated actuator devices are shown by four arrows labeled "F = ma / 4", and the total force is divided among their corresponding four actuator targets 608 (fewer or more actuator devices can be implemented). However, the two right actuator devices 610i use attraction (pull) to move support structure 604 to the left, and thus the scheme of FIG. 6 can be called a pull-pull scheme. As a result, it is possible to avoid the above-mentioned repulsion problem, while at the same time reducing the deformation of support structure 604 and maintaining the stress balance on fixed structure 614 (i.e., zeroing the average of the stress from the tension balance and the compression from the forward and backward movement). To decelerate and / or reverse the direction of movement, the corresponding actuator devices 610 and internal actuator devices 610i can be used in a pull-pull configuration.

[0095]

[0105] In some embodiments, adding the internal actuator device 610i and the extension structure 618 can have some undesirable consequences. One drawback is an increase in the cost of construction (additional parts and manufacturing complexity). Another drawback is that when moving the components, in addition to their inertia, the total weight increases. In FIG. 6, the mass of the coarse motion structure (support structure 606 and all that supports it) increases due to the four additional heavy electromagnets (internal actuator device 610i). The mass of the fine motion structure (support structure 606 and all that supports it) increases due to the addition of the extension structure 618. Further, the extension structure 618 can be sensitive to vibration, resulting in poor dynamics in the movement of the support structure 604. The additional uncertainty due to vibration affects the pattern transfer accuracy when the object 602 is used as a reticle for a lithography process.

[0096]

[0106] Some embodiments described herein provide structures and functions for addressing the problems of both the pull-only and pull-pull methods.

[0097]

[0107] FIGS. 7A and 7B show a stage 700 for supporting an object 702 according to some embodiments. In some embodiments, the stage 700 can have some features already described with reference to FIGS. 5 and 6. Compared to FIGS. 5 and 6, some elements may be non-displayed (for clarity) while additional elements may be shown. Unless otherwise described, the structures and functions previously described for the elements of FIGS. 5 and 6 are also applicable to the similarly numbered elements of FIGS. 7A and 7B (e.g., the reference numbers share the rightmost two digits). The structures and functions of at least some of the elements of FIGS. 7A and 7B are apparent from the description of the corresponding elements of FIGS. 5 and 6 and will not be reintroduced.

[0098]

[0108] Referring to FIG. 7A, in some embodiments, in addition to (or instead of certain features of) the features of stage 500 or 600 (FIGS. 5 and 6), stage 700 can comprise a shaft 718. The shaft 718 can be fixed to the support structure 704 using a fastener 720 (e.g., a pin, bolt, etc.). One or more load spreaders 722 can be used to surround a portion of the fastener 720. One or more of the actuator targets 708 can be fixed to the shaft 718 (e.g., one actuator target 708 at each end of the shaft) (the fixation can be achieved via welding, adhesive, epoxy, etc.). The actuator target 708 can be coupled to one or more stabilizers 724. The shaft implementation is repeatable because it has multiple shafts and corresponding attachment elements, as shown in FIG. 7A.

[0099]

[0109] In some embodiments, the shaft 718 can be fixed to the support structure 704 at location 726 of the support structure 704. The location 726 can be substantially along the centerline 728 of the support structure 704 (e.g., the centerline bisecting the support structure). When the corresponding actuator device 710 is activated to pull the actuator target 708, the shaft 718 can transmit a mechanical load from the actuator target 708 to the location 726 of the support structure 704. By dispersing the mechanical load in this way, the high-tension gradient of the stage 500 (FIG. 5) may be reduced. Instead, the strain effect can be divided into a compression region to the left of location 726 (assuming the pulling force is to the left) and a tensile region to the right of location 726. Due to the reconfiguration of the compression and tensile stresses in the support structure 704, the risk that the object 702 experiences slippage can be significantly reduced. Further, by having two actuator targets 708 fixed to opposite ends of the same shaft 718, the mechanical load can be more evenly dispersed. For example, when one actuator target is pulled to the left, a portion of the mechanical load transmitted by the shaft is transmitted to the subsequent actuator target. The force exerted by the subsequent actuator can push the support structure 704, thereby counteracting the inertial tendency to extend the chuck and zeroing the average stress within the epoxy over many scanning cycles.

[0100]

[0110] Figure 7B shows a cross-section of location 726 of support structure 704 according to some embodiments. In some embodiments, shaft 718 can pass through the interior of support structure 704. However, other implementations are envisioned, such as attaching shaft 718 to the outside of support structure 704 (e.g., referring to the orientation of the page of FIG. 7A, the upper end of support structure 704, the lower end of support structure 704, a recess on the surface of support structure 704, etc.). Support structure 704 can include a hole at location 726. Shaft 718 can also include a hole that aligns with the hole in support structure 704. Fastener 720 can be disposed within the holes of both support structure 704 and shaft 718 to fix the shaft to location 726.

[0101]

[0111] In some embodiments, support structure 704 can include one or more counterbores that align with the holes at location 726. Load spreader 722 can be disposed within each counterbore and the surrounding fastener 720 to distribute mechanical loads during acceleration. Load spreader 722 can include, for example, a diaphragm flexure. One or more load spreaders 722 can be fixed to the dish holes using an adhesive structure 730 (epoxy). Considering the movement of support structure 704 (e.g., scanned back and forth, left and right), the stress on the epoxy has a balance of compression and tension, which addresses the problem of tension imbalance on the epoxy used within stage 500 (FIG. 5). In some embodiments, the design can be such that clearance holes surround fastener 720 (not shown) so that no direct contact occurs between fastener 720 and support structure 704.

[0102]

[0112] Referring back to FIG. 7A, in some embodiments, the features of stage 700 can achieve certain desirable features of stages 500 and 600 while alleviating the above-mentioned drawbacks. For example, the setup of stage 700 can reduce components and footprint when compared to stage 600 (FIG. 6). Thus, there is no need to use the additional internal actuator devices 610i and the extension structure 618 (FIG. 6), reducing cost, weight, and space. Stage 500 used fewer actuator devices 510 (FIG. 5) than stage 600 (FIG. 6) and had high tension and deformation problems, but stage 700 does not need to increase the number of actuator devices and can alleviate tension deformation.

[0103]

[0113] In some embodiments, stage 700 can implement a low-volume solution to further enhance the dynamics of stage 700. For example, a stabilizer 724 can be used to reduce the impact of vibrations. The stabilizer 724 can be coupled to the actuator target 708. The stabilizer 724 can comprise a flexure.

[0104]

[0114] FIG. 8 shows a section of a support structure 804 according to some embodiments. In some embodiments, the support structure 804 can have an alternative shaft implementation when compared to the support structure 704 (FIG. 7). It should be understood that certain features of the support structure 704 are not shown for clarity of the figure. However, further features of the support structure 804 should be apparent from the description of FIGS. 5 through 7 and will not be reintroduced.

[0105]

[0115] In some embodiments, the shaft 818 can be used to transfer a load from an actuator target (e.g., 708 (FIG. 7)) to multiple locations of the support structure 804. The support structure 804 can include first, second, and / or third holes at corresponding first, second, and / or third locations of the support structure 804. The shaft 818 can also include first, second, and / or third holes that align with the corresponding holes of the support structure 804. The fastener 820 can be disposed within the holes of both the support structure 804 and the shaft 818 to secure the shaft at the first, second, and / or third locations of the support structure 804. By dispersing the load across multiple fasteners as opposed to placing all the load on a single fastener 720 (FIG. 7), it is possible to make the diameter of the fastener 820 smaller than that of the fastener 720 (FIG. 7).

[0106]

[0116] Exemplary actuating stage with a tension member

[0117] FIG. 9 shows a portion of a stage 900 for supporting an object (e.g., a wafer, a reticle, etc.) according to some embodiments. In some embodiments, the stage 900 can have some of the features already described with reference to FIGS. 5 - 8. Compared to FIGS. 5 - 8, some elements may be non - visible (for clarity) while additional elements may be shown. Unless otherwise stated, the structures and functions previously described for the elements of FIGS. 5 - 8 are also applicable to the similarly numbered elements of FIG. 9 (e.g., the reference numbers share the right - most two digits). The structures and functions of at least some of the elements of FIG. 9 will be apparent from the descriptions of the corresponding elements of FIGS. 5 - 8.

[0107]

[0118] In some embodiments, stage 900 can include a support structure 904, actuator targets 908 (e.g., three or more), one or more actuator devices 910, and a tension member 918'. The support structure can be a chuck that rides on another support structure (e.g., support structure 706 of FIGS. 7A and 7B). By way of non-limiting example, actuator devices 910-a and 910-b are shown as E-cores of electromagnets. Other types of electromagnet cores are contemplated. For example, some embodiments referring to the C-core of FIG. 10 are disclosed herein. Although wire coils are not explicitly shown in FIG. 9, their presence and function will be apparent to those skilled in the art based on the description of previous drawings (e.g., coil winding 512 (FIG. 5)) and magnetic field 930. Tension member 918' can be a loose or flexible material (e.g., cord), a rigid rod, etc. (e.g., shaft 718 (FIGS. 7A and 7B)).

[0108]

[0119] In some embodiments, support structure 904 can include a cavity portion 932 (e.g., a groove or channel). Tension member 918' is disposed within cavity portion 932. The dimensions of cavity portion 932 (e.g., cross-section, diameter, etc.) can be larger than the dimensions of tension member 918' such that tension member 918' can move within cavity portion 932. Cavity portion 932 can be implemented in several different ways (e.g., as a cavity channel, a groove external to support structure 904, one or more rings, etc.). Actuator targets 908-a, 908-b, 908-c, 908-d, 908-e, 908-f are explicitly shown (e.g., a first actuator target, a second actuator target, another actuator target, etc.). However, it should be understood that more or fewer actuator targets can be implemented.

[0109]

[0120] In some embodiments, the actuator device 910-a and the actuator targets 908-a, 908-c, and 908-e can be disposed on the side portion 934 (e.g., the first side portion) of the support structure 904. The actuator device 910-a can be disposed proximal to the actuator targets 908-a, 908-c, and 908-e (e.g., when the electromagnet is turned on, the electromagnet can attract the actuator targets). The actuator device 910-b and the actuator targets 908-b, 908-d, and 908-f can be disposed on the side portion 936 (e.g., the second side portion) opposite to the side portion 934 of the support structure 904. The actuator device 910-b can be disposed proximal to the actuator targets 908-b, 908-d, and 908-f.

[0110]

[0121] In some embodiments, in the case of an E-core, the first, second, and third structural protrusions of the E-core can be disposed opposite to their respective actuator targets. A C-core can be similarly arranged (two protrusions are opposite to two actuator targets instead of three protrusions). The E-core can be constructed from a single block of a magnetic permeability material or an assembly of two or more parts (e.g., two C-cores 938 attached to each other).

[0111]

[0122] In some embodiments, actuator targets 908-c and 908-e can be attached to side portion 934 of support structure 904. The attachment can be accomplished, for example, using an adhesive structure 914 (e.g., an adhesive such as epoxy). Actuator targets 908-a and 908-b can be attached to opposite ends of tension member 918'. For example, when actuator device 910-a is turned on to generate a magnetic field 930 at side portion 934 of support structure 904, the magnetic interaction can attract actuator targets 908-a, 908-c, and 908-e to move support structure 904 along a given direction. Further, tension member 918' can transmit a mechanical load to side portion 936 of support structure 904 via actuator target 908-b (e.g., the mechanical load transfer is based on the magnetic force applied on the first actuator target).

[0112]

[0123] In some embodiments, the dimensions (e.g., cross-section, diameter) of targets 908-a and 908-b can be larger than the dimensions of cavity portion 932 such that targets 908-a and 908-b cannot enter cavity portion 932. In this scenario, by using magnetic field 930 to pull target 908-a, target 908-b can "hook" onto side portion 936, thereby enabling a push movement of support structure 904 to complement the pull movement generated at side portion 934 via targets 908-c and 908-e. In this way, it is possible to increase the acceleration and speed of support structure 904 and further reduce (e.g., deform) the undesirable effects of simply pulling from one side of the support structure as described above with reference to the previous figures.

[0113]

[0124] In some embodiments, the actuator target 908-b can include a load spreader 940 to spread the mechanical load transmitted to the side portion 936. The actuator target 908-a can also include the load spreader 940. The load spreader 940 can include, for example, a soft pad, a coil spring, a flexure, a foldable structure, and the like.

[0114]

[0125] In some embodiments, the separation gap between the actuator targets 908-a and 908-c can be made small to prevent attenuation of the magnetic field 930. In particular, the gap between adjacent actuator targets can be made significantly smaller than the operating gap between an actuator target (e.g., 908-a) and the pole of an actuator device (e.g., 910-a). In non-limiting examples, significantly smaller can be 20% or less, 15% or less, 10% or less, 5% or less, from 20% to 5%, from 15% to 5%, from 15% to 10%, from 10% to 5%, and the like. When such conditions are imposed, the flux reduction caused by the gap between the actuator targets can be made negligible compared to the flux reduction caused by the operating gap between the actuator device and the actuator target (e.g., negligible can be less than a few percent effect on the force generated per unit current through the coil).

[0115]

[0126] In some embodiments, the operating gap between the actuator device and the actuator target can be 1500 microns or less, 1000 microns or less, 500 microns or less, and so on. Taking a 500-micron operating gap and a constraint of 10% or less as non-limiting examples, a 50-micron gap between two actuator targets can be considered negligible. On the other hand, there may be manufacturability issues that prevent the practical or economic manufacture of such small gaps. However, apart from considerations of practicality, the smaller the gap, the better the performance of the actuation (e.g., the force divided by the current in the coil).

[0116]

[0127] In some embodiments, when reducing manufacturing cost is preferred over high performance, for the looser (and perhaps easier to make) tolerance ranges, a gap of 200 microns or less may be desirable. As a trade-off, using more current may also worsen heating even at the same output. Considerations of thermal expansion also exist. By maximizing its electromagnetic performance, it is desirable to minimize heat generation by the actuator device. The separation gap between adjacent actuator targets 908-a and 908-c can be, for example, approximately 2 mm or less, 1 mm or less, 500 microns or less, 200 microns or less, 100 microns or less, 50 microns or less, 20 microns or less, or 10 microns or less. This feature regarding separation can be extended to the gaps between actuator targets 908-a and 908-e, 908-b and 908-d, and 908-b and 908-f.

[0117]

[0128] It will be appreciated that in some embodiments, the aforementioned functionality for moving the support structure 904 towards the left side of the figure (e.g., in a first direction) can be applied conversely for movement in the opposite direction to actuator device 910-b and actuator targets 908-b, 908-d, and 908-f.

[0118]

[0129] FIG. 10 shows a portion of a stage 1000 for supporting an object (e.g., a wafer, a reticle, etc.) according to some embodiments. In some embodiments, the stage 1000 can have some of the features already described with reference to FIGS. 5-9. Compared with FIGS. 5-9, some elements may be (for clarity) non-displayed while additional elements may be shown. Unless otherwise specified, the structures and functions previously described for the elements of FIGS. 5-9 are also applicable to the similarly numbered (e.g., the reference numbers share the two rightmost digits) elements of FIG. 10. The structures and functions of at least some of the elements of FIG. 10 will be apparent from the descriptions of the corresponding elements of FIGS. 5-9.

[0119]

[0130] In some embodiments, the actuator device 1010-a can be a C-core. The actuator targets 1008-a and 1008-c can be disposed proximal to the poles of the actuator device 1010-a. The structures and / or functions of the other elements shown in FIG. 10 can be the same as those described above with reference to the previous figures (e.g., the support structure 1004, the adhesion structure 1014, the tension member 1018’, the magnetic field 1030, the cavity portion 1032, the side portion 1034, and / or the load spreader 1040).

[0120]

[0131] Although this document particularly refers to the use of a lithographic apparatus in the manufacture of ICs, it should be appreciated that the lithographic apparatus described herein may have other applications. For example, this may be in the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, LCDs, thin film magnetic heads, etc. In view of such alternative applications, it will be recognized by those skilled in the art that where the terms "wafer" or "die" are used herein, they may be regarded as specific examples of the more general terms "substrate" or "target portion" respectively. The substrates described herein may be processed, before or after exposure, for example in a track unit (a tool typically used to apply a layer of resist to a substrate and develop the exposed resist), and / or in a metrology unit. Where appropriate, the disclosure herein can be applied to the above and other substrate processing tools. Further, the substrate can be processed multiple times, for example to create a multi-layer IC, and thus the term "substrate" as used herein can also refer to a substrate that already includes multiple processed layers.

[0121]

[0132] Although particular reference has been made to the use of aspects of the present disclosure in the field of optical lithography, it should be understood that the present disclosure may also be used in other applications, such as imprint lithography, depending on the context, and is not limited to optical lithography. In imprint lithography, the topography in the patterning device defines a pattern created on a substrate. The topography of the patterning device is imprinted into a resist layer supplied to the substrate, and the resist is hardened by applying electromagnetic radiation, heat, pressure, or a combination thereof. The patterning device is removed from the resist, and when the resist has hardened, a pattern remains inside.

[0122]

[0133] It should be understood that the terminology or phraseology of the present disclosure is for the purpose of explanation and not of limitation, and thus the terminology or phraseology of the present disclosure should be interpreted by those skilled in the art in light of the teachings of the present disclosure.

[0123]

[0134] As used herein, terms such as "radiation" and "beam of radiation" can encompass all types of electromagnetic radiation, such as ultraviolet (UV) radiation (e.g., having a wavelength λ of 365, 248, 193, 157, or 126 nm), extreme ultraviolet (EUV or soft X-ray) radiation (e.g., having a wavelength in the region of 5 - 20 nm, such as 13.5 nm), or hard X-rays working below 5 nm, or a material beam such as an ion beam or an electron beam. Terms such as "light" and "illumination" can refer to non-material radiation (e.g., photons, UV, X-rays, etc.). Generally, radiation having a wavelength between about 400 and about 700 nm is considered visible radiation, and radiation having a wavelength between about 780 - 3000 nm (or more) is considered IR radiation. UV refers to radiation with a wavelength of approximately 100 - 400 nm. In lithography, the term "UV" also applies to wavelengths that can be generated by a mercury discharge lamp, G-line 436 nm, H-line 405 nm, and / or I-line 365 nm. Vacuum UV, or VUV (i.e., UV absorbed by gas), refers to radiation having a wavelength of approximately 100 - 200 nm. Deep UV (DUV) generally refers to radiation having a wavelength in the range of 126 nm to 428 nm, and in some embodiments, an excimer laser can generate the DUV radiation used in a lithographic apparatus. For example, it should be understood that radiation having a wavelength in the range of 5 - 20 nm relates to radiation with a specific wavelength band, at least a part of which is within the range of 5 - 20 nm.

[0124]

[0135] It should be understood that for interpreting the claims, the section "Detailed Description of the Invention" is intended to be used rather than the sections "Summary of the Invention" and "Abstract". The sections "Summary of the Invention" and "Abstract" can describe one or more exemplary embodiments of the present disclosure as envisioned by the inventor, but cannot describe all exemplary embodiments, and thus are not intended to limit the present disclosure and the appended claims in any sense.

[0125]

[0136] Above, the present disclosure has been described using functional components that illustrate embodiments of a specific function and their relationships. The boundaries of these functional components are arbitrarily defined in this specification for convenience of explanation. Alternative boundaries can be defined as long as the specific function and its relationships are properly executed.

[0126]

[0137] Although specific aspects of the present disclosure have been described above, it will be understood that the aspects of the present disclosure can also be implemented in a manner different from the description. The description is illustrative and not limiting. Thus, it is clear that those skilled in the art can make changes to the disclosed present disclosure without departing from the scope of the claims defined below.

[0127]

[0138] The foregoing description of specific aspects has sufficiently clarified the overall nature of the present disclosure, so that by applying the knowledge of the relevant technical field, such specific aspects can be easily changed and / or adapted to various applications without undue experimentation and without departing from the overall concept of the present disclosure. Therefore, such adaptations and changes shall fall within the meaning and scope of equivalents of the disclosed aspects based on the teachings and guidance presented herein.

[0128]

[0139] The breadth and scope of the present disclosure are not limited by any of the above-described exemplary aspects, but are defined only by the claims and their equivalents.

[0129]

[0140] Aspects of the present disclosure can be further described using the following clauses. 1. A lighting system configured to illuminate a pattern of a patterning device, A projection system configured to project an image of the pattern onto a substrate, A stage configured to move the patterning device or the substrate, A first support structure configured to support the patterning device or the substrate, A second support structure configured to support the first support structure, An actuator device disposed on a second support structure and configured to move a first support structure along a direction, An actuator target configured to interact with the actuator device, A shaft fixed to a location in the actuator target and the first support structure, the shaft being configured to transmit a mechanical load from the actuator target to the location, A stage comprising, A lithographic apparatus comprising. 2. The first support structure comprises a hole at the location, The shaft comprises a hole, The stage is disposed within the holes of the first support structure and the shaft, and further comprises a fixture for fixing the shaft to the location, The lithographic apparatus according to claim 1. 3. The first support structure comprises a second hole at a second location of the first support structure, The shaft comprises the second hole, The stage is disposed within the second holes of the first support structure and the shaft, and further comprises a second fixture for fixing the shaft to the second location, The lithographic apparatus according to claim 2. 4. The lithographic apparatus according to claim 2, wherein the fixture is a pin or a bolt. 5. The lithographic apparatus according to claim 2, wherein the stage further comprises a load spreader disposed around the fixture and configured to spread the mechanical load. 6. The lithographic apparatus according to claim 5, wherein the load spreader comprises a diaphragm flexure. 7. The lithographic apparatus according to claim 5, wherein the load spreader is fixed to the first support structure by epoxy. 8. The stage, A second actuator device disposed on the second support structure and configured to move the first support structure along the direction, A second actuator target configured to interact with a second actuator device, A second shaft fixed to a second location of the second actuator target and the first support structure, the second shaft being configured to transmit a mechanical load from the second actuator target to the second location; Further comprising The lithographic apparatus according to claim 1. 9. The actuator target is a first actuator target fixed to an end of the shaft, The stage is A second actuator device disposed on the second support structure and configured to move the first support structure along the direction; A second actuator target configured to interact with the second actuator device, Further comprising The second actuator target is fixed to an end of the shaft opposite to the first actuator target, The shaft is further configured to transmit a part of the mechanical load from the first actuator target to the second actuator target. The lithographic apparatus according to claim 1. 10. The lithographic apparatus according to claim 1, wherein the shaft is disposed through the inside of the first support structure. 11. The lithographic apparatus according to claim 1, wherein the stage further comprises a stabilizer coupled to the actuator target, the stabilizer being configured to reduce vibration. 12. The lithographic apparatus according to claim 1, wherein the actuator device comprises an electromagnet. 13. The lithographic apparatus according to claim 1, wherein the first support structure comprises one or more position indicators. 14. A first support structure configured to support an object, A second support structure configured to support the first support structure, An actuator device disposed on the second support structure and configured to move the first support structure along a direction, An actuator target configured to interact with the actuator device, A shaft fixed to the location in the actuator target and the first support structure, the shaft being configured to transmit a mechanical load from the actuator target to the location, A movable stage comprising the above. 15. The first support structure has a hole at the location, The shaft has a hole, The movable stage is disposed in the holes of the first support structure and the shaft, and further comprises a fixture for fixing the shaft to the location, The movable stage according to clause 14. 16. The first support structure has a second hole at a second location of the first support structure, The shaft has the second hole, The movable stage is disposed in the second holes of the first support structure and the shaft, and further comprises a second fixture for fixing the shaft to the second location, The movable stage according to clause 15. 17. The movable stage according to clause 15, further comprising a load spreader disposed around the fixture and configured to spread the mechanical load. 18. The movable stage according to clause 16, wherein the load spreader comprises a diaphragm flexure. 19. A second actuator device disposed on the second support structure and configured to move the first support structure along the direction, A second actuator target configured to interact with the second actuator device, A second shaft fixed to the second location of the second actuator target and the first support structure, the second shaft being configured to transmit a mechanical load from the second actuator target to the second location, further comprising the movable stage according to clause 14. 20. The actuator target is a first actuator target fixed to the end of the shaft, the stage is disposed on a second support structure and a second actuator device configured to move the first support structure along the direction, and a second actuator target configured to interact with the second actuator device, further comprising the second actuator target is fixed to the end of the shaft opposite to the first actuator target, the shaft is further configured to transmit a part of the mechanical load from the first actuator target to the second actuator target, the movable stage according to clause 14. 21. The movable stage according to clause 14, further comprising a stabilizer coupled to the actuator target, the stabilizer being configured to reduce vibration. 22. The movable stage according to clause 14, wherein the actuator device comprises an electromagnet.

Claims

1. An illumination system configured to illuminate a pattern of a patterning device; A projection system configured to project an image of the pattern onto a substrate; A stage configured to move the patterning device or the substrate, the stage comprising: A support structure configured to support the patterning device or the substrate; A first actuator target disposed on a first side of the support structure; A second actuator target disposed on a second side of the support structure opposite the first side; A third actuator target attached to the first side of the support structure; An actuator device disposed proximal to the first and third targets and configured to interact magnetically with the first and third targets to move the support structure along a direction; A tension member, wherein the first and second actuator targets are attached to opposite ends of the tension member, and the tension member is configured to transmit a mechanical load to the second side of the support structure via the second actuator target based on a magnetic force exerted on the first actuator target; A stage comprising the above; A lithographic apparatus comprising the above.

2. The tension member is a flexible cord; The lithographic apparatus further comprises a frame configured to support the support structure and configured to make the support structure movable relative to the frame; The actuator device comprises a C-core; The lithographic apparatus according to Claim 1.

3. The stage further comprises another actuator target attached to the first side of the support structure; The actuator device comprises an E-core; The first, second, and third structural protrusions of the E-core are respectively disposed opposite to the first, second, and another target; The E-core comprises two C-cores attached to each other; The lithographic apparatus according to Claim 1.

4. The actuator device is further configured to move the support structure by pulling the first side portion via the third actuator target and by pushing the second side portion via the transmission of the mechanical load to the second side portion of the support structure via the second actuator target, the lithographic apparatus according to claim 1.

5. The actuator device is a first actuator device, The direction is a first direction, The stage, A fourth actuator target attached to the second side portion of the support structure, A second actuator device disposed proximal to the second and fourth targets and configured to interact magnetically with the second and fourth targets to move the support structure along a second direction opposite to the first direction, Further comprising, The tension member is further configured to transmit a mechanical load to the first side portion of the support structure via the first actuator target based on a magnetic force exerted on the second actuator target, The second actuator device is further configured to move the support structure by pulling the second side portion via the fourth actuator target and by pushing the first side portion via the transmission of the mechanical load to the first side portion of the support structure via the first actuator target, The lithographic apparatus according to claim 1.

6. The first and / or second actuator target comprises a load spreader for spreading the mechanical load over the second side portion, The third actuator target is attached to the first side portion via an epoxy adhesive, The separation gap between the first and third actuator targets is 200 microns or less, The lithographic apparatus according to claim 1.

7. The separation gap between the first and third actuator targets is 50 microns or less, the lithographic apparatus according to claim 1.

8. A support structure configured to support an object, A first actuator target disposed on a first side portion of the support structure, A second actuator target disposed on a second side of the support structure opposite to the first side; A third actuator target attached to the first side of the support structure; An actuator device disposed proximal to the first and third targets and configured to magnetically interact with the first and third targets to move the support structure along a single direction; A tension member, wherein the first and second actuator targets are attached to opposite ends of the tension member, and the tension member is configured to transmit a mechanical load to the second side of the support structure via the second actuator target based on a magnetic force exerted on the first actuator target; A stage comprising the above. **Claim 9** The tension member is a flexible cord; The stage further comprises a frame configured to support the support structure and configured to enable the support structure to move relative to the frame; The actuator device comprises a C-core; The stage according to claim 8. **Claim 10** The stage further comprises another actuator target attached to the first side of the support structure; The actuator device comprises an E-core; The first, second, and third structural protrusions of the E-core are disposed opposite to the first, second, and another target, respectively; The E-core comprises two C-cores attached to each other; The stage according to claim 8. **Claim 11** The stage according to claim 8, wherein the actuator device is further configured to move the support structure by pulling the first side via the third actuator target and by pushing the second side of the support structure via transmission of the mechanical load to the second side via the second actuator target. **Claim 12** The actuator device is a first actuator device; The direction is a first direction; The stage A fourth actuator target attached to the second side of the support structure; Disposed proximal to the second and fourth targets and configured to magnetically interact with the second and fourth targets to move the support structure along a second direction opposite to the first direction, a second actuator device; further comprising; the tension member is further configured to transmit a mechanical load to the first side portion of the support structure via the first actuator target based on a magnetic force exerted on the second actuator target; the second actuator device is further configured to move the support structure by pulling the second side portion via the fourth actuator target and by pushing the first side portion via the transmission of the mechanical load to the first side portion of the support structure via the first actuator target; The stage according to claim 8.

13. The first and / or second actuator targets comprise a load spreader for spreading the mechanical load over the second side portion; the third actuator target is attached to the first side portion via an epoxy adhesive; the separation gap between the first and third actuator targets is 200 microns or less; The stage according to claim 8.

14. The stage according to claim 8, wherein the separation gap between the first and third actuator targets is 50 microns or less.

Images