Split chuck

Abstract

A object chuck, comprising: a first body having mounts enabling it to be operatively driven by one or more motors, the first body being subjected to thermal-mechanical deformations and acceleration loads as a result of being driven; a second body configured to support an object clamp; and joints coupling the first body with the second body, the joints reducing the thermal-mechanical deformations and the acceleration loads from being transmitted from the first body to the second body.

Description

SPLIT CHUCKCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority of US application 63 / 649,634 which was filed on 20 May 2024 and which is incorporated herein in its entirety by reference.TECHNICAL FIELD

[0002] The description herein relates generally to a split chuck.BACKGROUND

[0003] A lithography (e.g., projection) apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such a case, a patterning device (e.g., a mask) may contain or provide a pattern corresponding to an individual layer of the IC (“design layout”), and this pattern can be transferred onto a target portion (e.g. comprising one or more dies) on a substrate (e.g., silicon wafer) that has been coated with a layer of radiation-sensitive material (“resist”), by methods such as irradiating the target portion through the pattern on the patterning device. In general, a single substrate contains a plurality of adjacent target portions to which the pattern is transferred successively by the lithographic projection apparatus, one target portion at a time. In one type of lithographic projection apparatus, the pattern on the entire patterning device is transferred onto one target portion in one operation. Such an apparatus is commonly referred to as a stepper. In an alternative apparatus, commonly referred to as a step-and-scan apparatus, a projection beam scans over the patterning device in a given reference direction (the “scanning” direction) while synchronously moving the substrate parallel or anti-parallel to this reference direction. Different portions of the pattern on the patterning device are transferred to one target portion progressively. In these lithography apparatuses, a patterning device is held by a patterning device chuck with an optically contacted clamp.

[0004] For photolithography stages, short stroke substrates and reticles stages are held by a substrate table, substrate clamp, or reticle clamp on a chuck of low expansion material that acts as a frame that holds both the metrology parts as well as the actuator mover parts that drive the stage. This holds for litho scanners as well as for metrology tools. In ambient conditions for DUV exposure, the clamping is done by vacuum force (underpressure), while for EUV systems the clamping is done by an electrostatic clamp in an extremely clean vacuum environment. The clamp uses an electrostatic force to hold the reticle to the clamp. During acceleration of the chuck, the electrostatic force keeps the reticle attached to the clamp. The clamp is held / supported by a chuck with ULE chuck, clamp, scales and fiducials, as well as actuator movers (magnets), wires for sensors and hoses for water cooling. Using the conventional reticle chuck, acceleration can reach up to 320 m / s2.

[0005] With the limiting factor being the acceleration that can be applied to the chuck, there arevarious techniques for speeding up the chuck acceleration. The conventional reticle chuck has a single body made of a low expansion material. By splitting the chuck into two bodies, a force frame for actuation and a metrology frame for clamping the reticle, the weight of the chuck is significantly lightened, allowing for increased chuck acceleration. In one example, only the metrology frame is made of low expansion material. The stiffness of the force frame enhances the stability of the metrology frame via joints used to connect the force frame to the metrology frame. Further, thermal and acceleration loads that originate from the force frame may be eliminated at the joint connections so that they are not transferred to the metrology frame, where high precision is necessary to achieve accurate exposure. As a result, a reticle chuck having a split chuck with joints in between allows for increased chuck acceleration and therefore, higher chip throughput. Therefore, the dynamics of the chuck can be increased, such as up to 2-3 times higher eigenfrequency and bandwidth, without compromising the stability and accuracy of the metrology frame by thermal loads and acceleration forces. At the same time, no compromises are made on the cleanliness of the stage environment, and no particles are allowed on the reticle.

[0006] In one embodiment, the reticle chuck includes (1) a high control bandwidth, which leads to a high eigenfrequency of greater than 4 kHz, (2) limited clamp deformation and no slip during acceleration in order to reach 96G for 3 times the current acceleration, and (3) limited deformation for the clamp, fiducials, and scales from thermal disturbance.SUMMARY

[0007] Among other things, the present application utilizes an object (e.g., reticle or wafer) chuck having two bodies connected by joints. A first body is a force frame having a high stiffness for driving the reticle chuck. The first body provides extra stiffness to a connected second body without disturbing its stability. The second body is a metrology frame of a low expansion material that holds the reticle for exposure. With a minimal volume and mass, the second body is nevertheless large enough to hold an object (e.g., reticle or wafer) clamp, scales, and fiducials. Joints connect the first body with the second body, providing stiffness to the second body and eliminating thermal and acceleration loads of the first body from negatively impacting the reticle exposure at the second body. The split chuck arrangement significantly reduces the weight of the reticle chuck, making it possible to increase the chuck acceleration by two to threefold.

[0008] According to an embodiment, there is provided an object chuck. The object chuck comprises a first body having mounts enabling it to be operatively driven by one or more motors, the first body being subjected to thermal-mechanical deformations and acceleration loads as a result of being driven; a second body configured to support an object clamp; and joints coupling the first body with the second body, the joints reducing the thermal-mechanical deformations and the acceleration loads from being transmitted from the first body to the second body.

[0009] In some embodiments, the joints are integrally formed with the first body and attached tothe second body.

[0010] In some embodiments, the joints are integrally formed with the second body and attached to the first body.

[0011] In some embodiments, the joints are separately formed from the first and second body and are attached to both the first body and the second body.

[0012] In some embodiments, the second body is made of a material having a zero coefficient of thermal expansion (CTE).

[0013] In some embodiments, the second body comprises ultra-low expansion material.

[0014] In some embodiments, the second body comprises lithium-aluminosilicate glass-ceramic.

[0015] In some embodiments, the second body comprises cordierite.

[0016] In some embodiments, the first body has a higher stiffness to density ratio in comparison to the second body.

[0017] In some embodiments, the first body comprises metal alloy or ceramic.

[0018] In some embodiments, each joint constrains 3 degrees of freedom of the second body.

[0019] In some embodiments, the joints are integrally molded from a glass or ceramic material together with one of either the first body or the second body, and connected to the other of the first body or the second body.

[0020] In some embodiments, the object chuck further comprises water cooling conduits on the first body and the second body.

[0021] In some embodiments, the object chuck further comprises temperature sensors at the first body for monitoring temperature gradients at the first body.

[0022] In some embodiments, the second body is configured to hold fiducials and scales, and wherein the first body is configured to engage with motor actuators.

[0023] In some embodiments, four or more joints are used to connect the first body with the second body.

[0024] In some embodiments, seven wire joints are integrally formed with the first body.

[0025] In some embodiments, each joint constrains one degree of freedom.

[0026] In some embodiments, the joints comprise 4 z-joints, 2 x-joints, and 1 y-joint.

[0027] In some embodiments, the joints comprise four sheet joints integrated with the first body.

[0028] In some embodiments, the four sheet joints are generally positioned at the corners of the first body and wherein the sheet joints are generally disposed at an angle of between 30 to 60 degrees with respect to the x- and y-axis.

[0029] In some embodiments, the 4 sheet joints each constrain 3 degrees of freedom to the second body.

[0030] In some embodiments, the joints comprise a plurality of joints that each have a particular z- directional stiffness integrated with or connected with the top surface of the second body.

[0031] In some embodiments, the joints have a pattern in an xy-plane and are etched in material ofthe second body.

[0032] In some embodiments, the joints are connected to the first body by epoxy or chemical bonding.

[0033] In some embodiments, the object chuck further comprises a releasable connection between the joints and the second body, thus enabling other second bodies to be connected to the first body.

[0034] In some embodiments, the mounts on the first body are configured to connect the first body with a short stroke motor.

[0035] In some embodiments, the joints are the only mechanisms that transfer force from the first body to the second body.

[0036] In some embodiments, the object chuck is a reticle chuck and the object clamp is a reticle clamp.BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate one or more embodiments and, together with the description, explain these embodiments. Embodiments will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

[0038] FIG. 1A is a schematic illustration of a reflective lithographic apparatus, according to an embodiment of the present disclosure.

[0039] FIG. IB is a schematic illustration of a transmissive lithographic apparatus, according to an embodiment of the present disclosure.

[0040] FIG. 1C is a more detailed schematic illustration of the reflective lithographic apparatus, according to an embodiment of the present disclosure.

[0041] FIG. 2 schematically depicts an embodiment of a lithographic cell or cluster, according to an embodiment.

[0042] FIG. 3 is a block diagram of an example computer system, according to an embodiment.

[0043] FIG. 4 is a schematic illustration of a reticle chuck, according to a first embodiment of the present disclosure.

[0044] FIG. 5 is a schematic illustration of joints for a reticle chuck, according to a second embodiment of the present disclosure.

[0045] FIG. 6 is a schematic illustration of joints for a reticle chuck, according to a third embodiment of the present disclosure.

[0046] FIG. 7 is a schematic illustration of joints for a reticle chuck, according to a fourth embodiment of the present disclosure.

[0047] FIG. 8 is a schematic illustration of joints for a reticle chuck, according to a fifth embodiment of the present disclosure.

[0048] FIG. 9 A is a schematic illustration of joints for a reticle chuck, according to a sixth embodiment of the present disclosure.

[0049] FIG. 9B is a schematic illustration of joints for a reticle chuck, according to a seventh embodiment of the present disclosure.

[0050] FIG. 10 is a schematic illustration of a second body for a reticle chuck, according to an embodiment of the present disclosure.DETAILED DESCRIPTION

[0051] Although specific reference may be made in this text to the manufacture of integrated circuits (ICs), it should be understood that the description herein has many other possible applications. For example, it may be employed in the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, liquid-crystal display panels, thin-film magnetic heads, etc. The skilled artisan will appreciate that, in the context of such alternative applications, any use of the terms “reticle”, “wafer” or “die” in this text should be considered as interchangeable with the more general terms “mask”, “substrate” and “target portion”, respectively. In addition, any use of the terms “reticle” or “mask” herein may be considered synonymous with the more general term “patterning device.”

[0052] As an introduction, prior to transferring a pattern from a patterning device such as a mask to a substrate, the substrate may undergo various procedures, such as priming, resist coating and a soft bake. After exposure, the substrate may be subjected to other procedures (“post-exposure procedures”), such as a post-exposure bake (PEB), development, a hard bake and measurement and / or other inspection of the transferred pattern. This array of procedures is used as a basis to make an individual layer of a device, e.g., an IC. The substrate may then undergo various processes such as etching, ion-implantation (doping), metallization, oxidation, chemical mechanical polishing, etc., all intended to finish an individual layer of the device. If several layers are required in the device, then the whole procedure, or a variant thereof, is repeated for each layer. Eventually, a device will be present in each target portion on the substrate. These devices are then separated from one another by a technique such as dicing or sawing, whence the individual devices can be mounted on a carrier, connected to pins, etc.

[0053] Manufacturing devices, such as semiconductor devices, typically involves processing a substrate (e.g., a semiconductor wafer) using a number of fabrication processes to form various features and multiple layers of the devices. Such layers and features are typically manufactured and processed using, e.g., deposition, lithography, etch, chemical mechanical polishing, ion implantation, and / or other processes. Multiple devices may be fabricated on a plurality of dies on a substrate and then separated into individual devices. This device manufacturing process may be considered a patterning process. A patterning process involves a patterning step, such as optical and / or nanoimprint lithography using a patterning device in a lithographic apparatus, to transfer a pattern onthe patterning device to a substrate and typically, but optionally, involves one or more related pattern processing steps, such as resist development by a development apparatus, baking of the substrate using a bake tool, etching using the pattern using an etch apparatus, etc. One or more metrology processes are typically involved in the patterning process.

[0054] Lithography is a step in the manufacturing of devices such as ICs, where patterns formed on substrates define functional elements of the devices, such as microprocessors, memory chips, etc. Similar lithographic techniques are also used in the formation of flat panel displays, micro-electro mechanical systems (MEMS) and other devices.

[0055] As semiconductor manufacturing processes continue to advance, the dimensions of functional elements have continually been reduced while the number of functional elements, such as transistors, per device has been steadily increasing over decades, following a trend commonly referred to as “Moore’s law”. At the current state of technology, layers of devices are manufactured using lithographic projection apparatuses that project a design layout onto a substrate using illumination from a deep-ultraviolet illumination source, creating individual functional elements having dimensions well below 100 nm, i.e. less than half the wavelength of the radiation from the illumination source (e.g., a 193 nm illumination source).

[0056] This process in which features with dimensions smaller than the classical resolution limit of a lithographic projection apparatus are printed, is commonly known as low-kl lithography, according to the resolution formula CD = klxk / NA, where I is the wavelength of radiation employed (currently in most cases 248nm or 193nm), NA is the numerical aperture of projection optics in the lithographic projection apparatus, CD is the “critical dimension’ -generally the smallest feature size printed-and kl is an empirical resolution factor. In general, the smaller kl the more difficult it becomes to reproduce a pattern on the substrate that resembles the shape and dimensions planned by a designer in order to achieve particular electrical functionality and performance. To overcome these difficulties, sophisticated fine-tuning steps are applied to the lithographic projection apparatus, the design layout, or the patterning device. These include, for example, but not limited to, optimization of NA and optical coherence settings, customized illumination schemes, use of phase shifting patterning devices, optical proximity correction (OPC, sometimes also referred to as “optical and process correction”) in the design layout, overlay measurement, or other methods generally defined as “resolution enhancement techniques” (RET).

[0057] The term “projection optics” as used herein should be broadly interpreted as encompassing various types of optical systems, including refractive optics, reflective optics, apertures and catadioptric optics, for example. The term “projection optics” may also include components operating according to any of these design types for directing, shaping, or controlling the projection beam of radiation, collectively or singularly. The term “projection optics” may include any optical component in the lithographic projection apparatus, no matter where the optical component is located on an optical path of the lithographic projection apparatus. Projection optics may include opticalcomponents for shaping, adjusting and / or projecting radiation from the source before the radiation passes the patterning device, and / or optical components for shaping, adjusting and / or projecting the radiation after the radiation passes the patterning device. The projection optics generally exclude the source and the patterning device.

[0058] FIGS. 1A and IB are schematic illustrations of a lithographic apparatus 100 and lithographic apparatus 100’, in or for which embodiments of the present disclosure may be implemented. Lithographic apparatus 100 and lithographic apparatus 100’ each include the following: an illumination system (illuminator) IL configured to condition a radiation beam B (for example, ultraviolet (UV), deep ultraviolet (DUV) or extreme ultraviolet (EUV) radiation); a support structure (for example, a mask table) MT configured to support a patterning device (for example, 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 (for example, a wafer table) WT (e.g., WTa, WTb or both) configured to hold a substrate (for example, a resist coated wafer) W and connected to a second positioner PW configured to accurately position the substrate W. Lithographic apparatus 100 and 100’ also have a projection system PS configured to project a pattern imparted to the radiation beam B by patterning device MA onto a target portion (for example, comprising one or more dies) C of the substrate W. In lithographic apparatus 100, the patterning device MA and the projection system PS are reflective. In lithographic apparatus 100’, the patterning device MA and the projection system PS are transmissive.

[0059] The illumination system IL may 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.

[0060] The support structure MT holds the patterning device MA in a manner that depends on the orientation of the patterning device MA, the design of at least one of the lithographic apparatus 100 and 100’, and other conditions, such as whether or not the patterning device MA is held in a vacuum environment. The support structure MT may use mechanical, vacuum, electrostatic, or other clamping techniques to hold the patterning device MA. The support structure MT can be a frame or a table, for example, which can be fixed or movable, as required. By using sensors, the support structure MT can ensure that the patterning device MA is at a desired position, for example, with respect to the projection system PS.

[0061] The term “patterning device” MA should be broadly interpreted as referring to any device that can be used to impart a radiation beam B with a pattern in its cross-section, such as to create a pattern in the target portion C of the substrate W. The pattern imparted to the radiation beam B can correspond to a particular functional layer in a device being created in the target portion C to form an integrated circuit.

[0062] The patterning device MA may be transmissive (as in lithographic apparatus 100’ of FIG. IB) or reflective (as in lithographic apparatus 100 of FIG. 1 A). Examples of patterning devices MAinclude reticles, masks, programmable mirror arrays, and programmable LCD panels. Masks are well known in lithography, and include mask types such as binary, alternating phase shift, and attenuated phase shift, as well as various hybrid mask types. An example of a programmable mirror array employs a matrix arrangement of small mirrors, each of which can be individually tilted so as to reflect an incoming radiation beam in different directions. The tilted mirrors impart a pattern in the radiation beam B which is reflected by a matrix of small mirrors.

[0063] The term “projection system” PS can encompass any type of projection system, including refractive, reflective, catadioptric, magnetic, electromagnetic and electrostatic optical systems, or any combination thereof, as appropriate for the exposure radiation being used, or for other factors, such as the use of an immersion liquid on the substrate W or the use of a vacuum. A vacuum environment can be used for EUV or electron beam radiation since other gases can absorb too much radiation or electrons. A vacuum environment can therefore be provided to the whole beam path with the aid of a vacuum wall and vacuum pumps.

[0064] Lithographic apparatus 100 and / or lithographic apparatus 100’ can be of a type having two (dual stage) or more substrate tables WT (and / or two or more mask tables). In such “multiple stage” machines, the additional substrate tables WT can be used in parallel, or preparatory steps can be carried out on one or more tables while one or more other substrate tables WT are being used for exposure. In some situations, the additional table may not be a substrate table WT. For example, alignment measurements using an alignment sensor AS and / or level (height, tilt, etc.) measurements using a level sensor LS may be made (in FIG. IB).

[0065] Referring to FIGS. 1 A and IB, the illuminator IL receives a radiation beam from a radiation source SO. The source SO and the lithographic apparatus 100, 100’ can be separate physical entities, for example, when the source SO is an excimer laser. In such cases, the source SO is not considered to form part of the lithographic apparatus 100 or 100’, and the radiation beam B passes from the source SO to the illuminator IL with the aid of a beam delivery system BD (in FIG. IB) including, for example, suitable directing mirrors and / or a beam expander. In other cases, the source SO can be an integral part of the lithographic apparatus 100, 100’ — for example when the source SO is a mercury lamp. The source SO and the illuminator IL, together with the beam delivery system BD, if required, can be referred to as a radiation system.

[0066] The illuminator IL may alter the intensity distribution of the beam. The illuminator may be arranged to limit the radial extent of the radiation beam such that the intensity distribution is non-zero within an annular region in a pupil plane of the illuminator IL. Additionally or alternatively, the illuminator IL may be operable to limit the distribution of the beam in the pupil plane such that the intensity distribution is non-zero in a plurality of equally spaced sectors in the pupil plane. The intensity distribution of the radiation beam in a pupil plane of the illuminator IL may be referred to as an illumination mode.

[0067] The illuminator IL can include an adjuster AD (in FIG. IB) for adjusting the angularintensity distribution of the radiation beam. Generally, at least the outer and / or inner radial extent (commonly referred to as “o-outer” and “o-inner,” respectively) of the intensity distribution in a pupil plane of the illuminator can be adjusted. In addition, the illuminator IL can comprise various other components (in FIG. IB), such as an integrator IN and a condenser CN. The illuminator IL can be used to condition the radiation beam B to have a desired uniformity and intensity distribution in its cross section.

[0068] Referring to FIG. 1A, the radiation beam B is incident on the patterning device (for example, mask) MA, which is held on the support structure (for example, mask table) MT, and is patterned by the patterning device MA. In lithographic apparatus 100, the radiation beam B is reflected from the patterning device (for example, mask) MA. After being reflected from the patterning device (for example, mask) MA, the radiation beam B passes through the projection system PS, which focuses the radiation beam B onto a target portion C of the substrate W. With the aid of the second positioner PW and position sensor IF2 (for example, an interferometric device, linear encoder, or capacitive sensor), the substrate table WT can be moved accurately (for example, so as to position different target portions C in the path of the radiation beam B). Similarly, the first positioner PM and another position sensor IF1 (for example, an interferometric device, linear encoder, or capacitive sensor) can be used to accurately position the patterning device (for example, mask) MA with respect to the path of the radiation beam B. Patterning device (for example, mask) MA and substrate W can be aligned using mask alignment marks Ml, M2 and substrate alignment marks Pl, P2.

[0069] Referring to FIG. IB, the radiation beam B is incident on the patterning device (for example, mask MA), which is held on the support structure (for example, mask table MT), and is patterned by the patterning device. Having traversed the mask MA, the radiation beam B passes through the projection system PS, which focuses the beam onto a target portion C of the substrate W. The projection system PS is supported on a reference frame RF.

[0070] The terms “radiation” and “beam” used herein encompass all types of electromagnetic radiation, including ultraviolet (UV) or deep ultraviolet (DUV) radiation (e.g. having a wavelength of 365, 248, 193, 157 or 126 nm) and extreme ultra-violet (EUV) radiation (e.g. having a wavelength in the range of 5-20 nm), as well as particle beams, such as ion beams or electron beams.

[0071] With the aid of the second positioner PW and position sensor IF2 (for example, an interferometric device, linear encoder, or capacitive sensor), the substrate table WT can be moved accurately (for example, so as to position different target portions C in the path of the radiation beam B). The position sensor IF2 measures the substrate table WT in three dimensions. In this example, the position sensor IF2 is an interferometric device. The z-direction interferometers are positioned to the side of the substrate table WT. The interferometric mirrors have 45-degree angled surfaces attached to the left and the right side of the substrate table WT. The interferometric lasers are mounted such that the laser light is incident upon the interferometric mirrors. FIG. IB shows the relationship between the interferometric lasers and the mirrors of the position sensor IF2. Similarly,the first positioner PM and another position sensor IF1 (shown in FIG. 1A) can be used to accurately position the mask MA with respect to the path of the radiation beam B (for example, after mechanical retrieval from a mask library or during a scan). The position sensor IF1 measures the mask table MT in three dimensions. In this example, the position sensor IF1 is an interferometric device. The z- direction interferometers are positioned to the side of the mask table MT. The interferometric mirrors have 45-degree angled surfaces attached to the left and the right side of the mask table MT. The interferometric lasers are mounted such that the laser light is incident upon the interferometric mirrors.

[0072] In general, 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), which form part of the first positioner PM. Similarly, movement of the substrate table WT can be realized using a long-stroke module and a short-stroke module, which form part of the second positioner PW. In the case of a stepper (as opposed to a scanner), the mask table MT can be connected to a short-stroke actuator only or can be fixed. Mask MA and substrate W can be aligned using mask alignment marks Ml, M2, and substrate alignment marks Pl, P2. Although the substrate alignment marks (as illustrated) occupy dedicated target portions, they can be located in spaces between target portions (known as scribe-lane alignment marks). Similarly, in situations in which more than one die is provided on the mask MA, the mask alignment marks can be located between the dies.

[0073] The lithographic apparatus 100 and 100’ can be used in at least one of the following modes:

[0074] 1. In step mode, the support structure (for example, mask table) MT and the substrate tableWT are kept essentially stationary, while an entire pattern imparted to the radiation beam B is projected onto a target portion C at one time (i.e., a single static exposure). The substrate table WT is then shifted in the X and / or Y direction so that a different target portion C can be exposed.

[0075] 2. In scan mode, the support structure (for example, mask table) MT and the substrate tableWT are scanned synchronously while a pattern imparted to the radiation beam B is projected onto a target portion C (i.e., a single dynamic exposure). The velocity and direction of the substrate table WT relative to the support structure (for example, mask table) MT can be determined by the (de-)magnification and image reversal characteristics of the projection system PS.

[0076] 3. In another mode, the support structure (for example, mask table) MT is kept substantially stationary holding a programmable patterning device, and the substrate table WT is moved or scanned while a pattern imparted to the radiation beam B is projected onto a target portion C. A pulsed radiation source SO can be employed and the programmable patterning device is updated as required after each movement of the substrate table WT or in between successive radiation pulses during a scan. This mode of operation can be readily applied to maskless lithography that utilizes a programmable patterning device, such as a programmable mirror array.

[0077] Combinations and / or variations on the described modes of use or entirely different modes of use can also be employed.

[0078] In some embodiments, lithographic apparatus 100 includes an extreme ultraviolet (EUV) source, which is configured to generate a beam of EUV radiation for EUV lithography. In general, the EUV source is configured in a radiation system, and a corresponding illumination system is configured to condition the EUV radiation beam of the EUV source.

[0079] FIG. 1C shows the lithographic apparatus 100 in more detail, including the source collector apparatus SO, the illumination system IL, and the projection system PS. The source collector apparatus SO is constructed and arranged such that a vacuum environment can be maintained in an enclosing structure 120 of the source collector apparatus SO. An EUV radiation emitting plasma 110 may be formed by a discharge produced plasma source. EUV radiation may be produced by a gas or vapor, for example Xe gas, Li vapor or Sn vapor in which the hot plasma 110 is created to emit radiation in the EUV range of the electromagnetic spectrum. The hot plasma 110 is created by, for example, an electrical discharge causing an at least partially ionized plasma. Partial pressures of, for example, 10 Pa of Xe, Li, Sn vapor or any other suitable gas or vapor may be required for efficient generation of the radiation. In an embodiment, a plasma of excited tin (Sn) is provided to produce EUV radiation.

[0080] The radiation emitted by the hot plasma 110 is passed from a source chamber 111 into a collector chamber 112 via an optional gas barrier or contaminant trap 113 (in some cases also referred to as contaminant barrier or foil trap) which is positioned in or behind an opening in source chamber 111. The contaminant trap 113 may include a channel structure. Contamination trap 113 may also include a gas barrier or a combination of a gas barrier and a channel structure. The contaminant trap 113 further indicated herein at least includes a channel structure, as known in the art.

[0081] The collector chamber 112 may include a radiation collector CO which may be a so-called grazing incidence collector. Radiation collector CO has an upstream radiation collector side 151 and a downstream radiation collector side 152. Radiation that traverses collector CO can be reflected off a grating spectral filter 140 to be focused at a virtual source point IFP. The virtual source point IFP is commonly referred to as the intermediate focus, and the source collector apparatus is arranged such that the intermediate focus IFP is located at or near an opening 119 in the enclosing structure 120. The virtual source point IFP is an image of the radiation emitting plasma 110. Grating spectral filter 140 is used in particular for suppressing infra-red (IR) radiation.

[0082] Subsequently the radiation traverses the illumination system IL, which may include a facetted field mirror device 122 and a facetted pupil mirror device 124 arranged to provide a desired angular distribution of the radiation beam 121, at the patterning device MA, as well as a desired uniformity of radiation intensity at the patterning device MA. Upon reflection of the radiation beam 121 at the patterning device MA, held by the support structure MT, a patterned beam 126 is formed and the patterned beam 126 is imaged by the projection system PS via reflective elements 128, 130 onto a substrate W held by the wafer stage or substrate table WT.

[0083] More elements than shown may generally be present in illumination optics unit IL andprojection system PS. The grating spectral filter 140 may optionally be present, depending upon the type of lithographic apparatus. Further, there may be more mirrors present than those shown in the FIGS., for example there may be 1-6 additional reflective elements present in the projection system PS than shown in FIG. 1C.

[0084] Collector optic CO, as illustrated in FIG. 1C, is depicted as a nested collector with grazing incidence reflectors 153, 154 and 155, just as an example of a collector (or collector mirror). The grazing incidence reflectors 153, 154 and 155 are disposed axially symmetric around an optical axis O and a collector optic CO of this type is preferably used in combination with a discharge produced plasma source, often called a DPP source.

[0085] As shown in FIG. 2, the lithographic apparatus 100 or 100’ (indicated as “LA” in Fig. 2) may form part of a lithographic cell LC, also sometimes referred to as a lithocell or cluster, which also includes apparatuses to perform pre- and post-exposure processes on a substrate. Conventionally these include one or more spin coaters SC to deposit one or more resist layers, one or more developers to develop exposed resist, one or more chill plates CH and / or one or more bake plates BK. A substrate handler, or robot, RO picks up one or more substrates from input / output port I / Ol, I / O2, moves them between the different process apparatuses and delivers them to the loading bay LB of the lithographic apparatus. These apparatuses, which are often collectively referred to as the track, are under the control of a track control unit TCU which is itself controlled by the supervisory control system SCS, which also controls the lithographic apparatus via lithography control unit LACU. Thus, the different apparatuses can be operated to maximize throughput and processing efficiency.

[0086] In order that a substrate that is exposed by the lithographic apparatus is exposed correctly and consistently and / or in order to monitor a part of the patterning process (e.g., a device manufacturing process) that includes at least one pattern transfer step (e.g., an optical lithography step), it is desirable to inspect a substrate or other object to measure or determine one or more properties such as alignment, overlay (which can be, for example, between structures in overlying layers or between structures in a same layer that have been provided separately to the layer by, for example, a double patterning process), line thickness, critical dimension (CD), focus offset, a material property, etc. For example, contamination on reticle clamp membranes (e.g., as described herein) may adversely affect overlay because clamping a reticle over such contamination will distort the reticle. Accordingly, a manufacturing facility in which lithocell LC is located also typically includes a metrology system that measures some or all of the substrates W (FIGS. 1A-1C) that have been processed in the lithocell or other objects in the lithocell. The metrology system may be part of the lithocell LC, for example it may be part of the lithographic apparatus 100 or 100’.

[0087] The one or more measured parameters may include, for example, alignment, overlay between successive layers formed in or on the patterned substrate, critical dimension (CD) (e.g., critical linewidth) of, for example, features formed in or on the patterned substrate, focus or focus error of an optical lithography step, dose or dose error of an optical lithography step, opticalaberrations of an optical lithography step, etc. This measurement may be performed on a target of the product substrate itself and / or on a dedicated metrology target provided on the substrate. The measurement can be performed after-development of a resist but before etching, after-etching, after deposition, and / or at other times.

[0088] There are various techniques for making measurements of the structures formed in the patterning process, including the use of a scanning electron microscope, an image-based measurement tool and / or various specialized tools. As discussed above, a fast and non-invasive form of specialized metrology tool is one in which a beam of radiation is directed onto a target on the surface of the substrate and properties of the scattered (diffracted / reflected) beam are measured. By evaluating one or more properties of the radiation scattered by the substrate, one or more properties of the substrate can be determined. This may be termed diffraction-based metrology. One such application of this diffraction-based metrology is in the measurement of feature asymmetry within a target. This can be used as a measure of overlay, for example, but other applications are also known. For example, asymmetry can be measured by comparing opposite parts of the diffraction spectrum (for example, comparing the -1stand +lstorders in the diffraction spectrum of a periodic grating). Another application of diffraction-based metrology is in the measurement of feature width (CD) within a target.

[0089] Thus, in a device fabrication process (e.g., a patterning process, a lithography process, etc.), a substrate or other objects may be subjected to various types of measurement during or after the process. The measurement may determine whether a particular substrate is defective, may establish adjustments to the process and apparatuses used in the process (e.g., aligning two layers on the substrate or aligning the patterning device to the substrate), may measure the performance of the process and the apparatuses, or may be for other purposes. Examples of measurement include optical imaging (e.g., optical microscope), non-imaging optical measurement (e.g., measurement based on diffraction such as the ASML YieldStar metrology tool, the ASML SMASH metrology system), mechanical measurement (e.g., profiling using a stylus, atomic force microscopy (AFM)), and / or non- optical imaging (e.g., scanning electron microscopy (SEM)).

[0090] Metrology results may be provided directly or indirectly to the supervisory control system SCS. If an error is detected, an adjustment may be made to exposure of a subsequent substrate (especially if the inspection can be done soon and fast enough that one or more other substrates of the batch are still to be exposed) and / or to subsequent exposure of the exposed substrate. Also, an already exposed substrate may be stripped and reworked to improve yield, or discarded, thereby avoiding performing further processing on a substrate known to be faulty. In a case where only some target portions of a substrate are faulty, further exposures may be performed only on those target portions which meet specifications.

[0091] Within a metrology system, a metrology apparatus is used to determine one or more properties of the substrate, and in particular, how one or more properties of different substrates vary,or different layers of the same substrate vary from layer to layer. As noted above, the metrology apparatus may be integrated into the lithographic apparatus LA or the lithocell LC or may be a standalone device.

[0092] To enable the metrology, one or more targets can be provided on the substrate. In an embodiment, the target is specially designed and may comprise a periodic structure. In an embodiment, the target is a part of a device pattern, e.g., a periodic structure of the device pattern. In an embodiment, the device pattern is a periodic structure of a memory device (e.g., a Bipolar Transistor (BPT), a Bit Line Contact (BLC), etc. structure).

[0093] In an embodiment, the target on a substrate may comprise one or more 1-D periodic structures (e.g., gratings), which are printed such that after development, the periodic structural features are formed of solid resist lines. In an embodiment, the target may comprise one or more 2-D periodic structures (e.g., gratings), which are printed such that after development, the one or more periodic structures are formed of solid resist pillars or vias in the resist. The bars, pillars, or vias may alternatively be etched into the substrate (e.g., into one or more layers on the substrate).

[0094] In an embodiment, one of the parameters of interest of a patterning process is overlay. Overlay can be measured using dark field scatterometry in which the zeroth order of diffraction (corresponding to a specular reflection) is blocked, and only higher orders processed. Diffractionbased overlay using dark-field detection of the diffraction orders enables overlay measurements on smaller targets. These targets can be smaller than the illumination spot and may be surrounded by device product structures on a substrate. In an embodiment, multiple targets can be measured in one radiation capture.

[0095] As lithography nodes keep shrinking, more and more complicated wafer designs may be implemented. Various tools and / or techniques may be used by designers to ensure complex designs are accurately transferred to physical wafers. These tools and techniques may include mask optimization, source mask optimization (SMO), OPC, design for control, and / or other tools and / or techniques. For example, a source mask optimization process is described in United States Patent No. 9,588,438 titled “Optimization Flows of Source, Mask and Projection Optics”, which is incorporated in its entirety by reference.

[0096] The present systems, and / or methods may be used as stand-alone tools and / or techniques, and / or or used in conjunction with semiconductor manufacturing processes, to enhance the accurate transfer of complex designs to physical wafers.

[0097] FIG. 3 is a block diagram that illustrates a computer system CS that can assist in implementing the methods, flows, or the system(s) disclosed herein. Computer system CS may be included in and / or electronically coupled to the lithography apparatus 100 or 100’ described above (FIGS. 1A-1C). Computer system CS includes a bus BS or other communication mechanism for communicating information, and a processor PRO1 (or multiple processors PRO1, PRO2, etc.) coupled with bus BS for processing information. Computer system CS also includes a main memoryMM, such as a random access memory (RAM) or other dynamic storage device, coupled to bus BS for storing information and instructions to be executed by processor PRO1. Main memory MM also may be used for storing temporary variables or other intermediate information during execution of instructions to be executed by processor PRO1. Computer system CS further includes a read only memory ROM or other static storage device coupled to bus BS for storing static information and instructions for processor PRO1. A storage device SD, such as a magnetic disk or optical disk, is provided and coupled to bus BS for storing information and instructions.

[0098] Computer system CS may be coupled via bus BS to a display DS, such as a cathode ray tube (CRT) or flat panel or touch panel display for displaying information to a computer user. An input device ID, including alphanumeric and other keys, is coupled to bus BS for communicating information and command selections to processor PRO1. Another type of user input device is cursor control CC, such as a mouse, a trackball, or cursor direction keys for communicating direction information and command selections to processor ROM and for controlling cursor movement on display DS. This input device typically has two degrees of freedom in two axes, a first axis (e.g., X) and a second axis (e.g., Y), that allows the device to specify positions in a plane. A touch panel (screen) display may also be used as an input device.

[0099] According to one embodiment, portions of one or more flows and / or methods described herein may be performed by computer system CS in response to processor PRO1 executing one or more sequences of one or more instructions contained in main memory MM. Such instructions may be read into main memory MM from another computer-readable medium, such as storage device SD. Execution of the sequences of instructions contained in main memory MM causes processor PRO1 to perform the flows and / or process steps described herein. One or more processors in a multi-processing arrangement may also be employed to execute the sequences of instructions contained in main memory MM. In an alternative embodiment, hard-wired circuitry may be used in place of or in combination with software instructions. Thus, the description herein is not limited to any specific combination of hardware circuitry and software.

[0100] The term “computer-readable medium” or “machine readable medium” as used herein refers to any medium that participates in providing instructions to processor PRO1 for execution. Such a medium may take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media include, for example, optical or magnetic disks, such as storage device SD. Volatile media include dynamic memory, such as main memory MM. Transmission media include coaxial cables, copper wire and fiber optics, including the wires that comprise bus BS. Transmission media can also take the form of acoustic or light waves, such as those generated during radio frequency (RF) and infrared (IR) data communications. Common forms of computer-readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave as described hereinafter, or any other medium from which a computer can read.

[0101] Various forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to processor PRO1 for execution. For example, the instructions may initially be borne on a magnetic disk of a remote computer. The remote computer can load the instructions into its dynamic memory and send the instructions over a network such as the internet. A modem local to computer system CS can receive the data and use an infrared transmitter to convert the data to an infrared signal. An infrared detector coupled to bus BS can receive the data carried in the infrared signal and place the data on bus BS. Bus BS carries the data to main memory MM, from which processor PRO1 retrieves and executes the instructions. The instructions received by main memory MM may optionally be stored on storage device SD either before or after execution by processor PRO1.

[0102] Computer system CS may also include a communication interface CI coupled to bus BS. Communication interface CI provides a two-way data communication coupling to a network link NL that is connected to a local network LAN. For example, communication interface CI may be an integrated services digital network (ISDN) card or a modem to provide a data communication connection to a corresponding type of telephone line. As another example, communication interface CI may be a local area network (LAN) card to provide a data communication connection to a compatible LAN. Wireless links may also be implemented. In any such implementation, communication interface CI sends and receives electrical, electromagnetic, or optical signals that carry digital data streams representing various types of information.

[0103] Network link NL typically provides data communication through one or more networks to other data devices. For example, network link NL may provide a connection through local network LAN to a host computer HC or to data equipment operated by an Internet Service Provider ISP. Internet Service Provider ISP in turn provides data communication services through the worldwide packet data communication network, now commonly referred to as the “Internet” INT. Local network LAN and Internet INT both use electrical, electromagnetic, or optical signals that carry digital data streams. The signals through the various networks and the signals on network link NL and through communication interface CI, which carry the digital data to and from computer system CS, are exemplary forms of carrier waves transporting the information.

[0104] Computer system CS can send messages and receive data, including program code, through the network(s), network link NL, and communication interface CL In the Internet example, a server SV might transmit a requested code for an application program through Internet INT, Internet Service Provider ISP, local network LAN and communication interface CL One such downloaded application may provide all or part of a method described herein, for example. The received code may be executed by processor PRO1 as it is received, and / or stored in storage device SD, or other nonvolatile storage for later execution. In this manner, computer system CS may obtain application codein the form of a carrier wave.

[0105] FIG. 4 is a schematic illustration of a reticle chuck 1 , according to a first embodiment of the present disclosure. It should be appreciated that in other embodiments, the reticle chuck 1 of FIG. 4, and the joints shown in FIGS. 5-10, can be applied to a wafer chuck and / or wafer clamp, or to a chuck and / or clamp configured to support any other object. The reticle chuck 1 is similar to the support structure (or the mask table) MT as shown in FIGS. 1A-1C. The reticle chuck 1 includes a first body 2 and a second body 3 connected by joints 5. The first body 2 is a force frame to which mounts 8 and motors 6 are attached. The first body 2 is a stiff yet lightweight frame that can be driven at a high acceleration. The location of motors 6 in a z-direction is chosen such that the complete reticle chuck assembly including reticle is driven in its center of gravity. This prevents drive torques in a Redirection. The mounts 8 are connected to the first body 2 to enable the first body 2 to be driven by one or more motors 6. The mounts 8 on the first body 2 are configured to connect the first body 2 with the motors 6, which are part of a short stroke assembly. The motors 6 actuate the first body 2 in a y- direction. Movement of the first body 2 results in displacement of the connected joints 5 and second body 3. As a result, the motors 6 cause movement of the entire reticle chuck 1. Further, during the drive of the first body 2, the motors 6 generate heat and temperature gradients. Consequently, the shape of the first body 2 will change due to the thermal effects. In turn, the first body 2 creates thermal-mechanical deformations and acceleration loads as a result of being driven. These loads are undesired and could negatively impact the exposure. It is imperative to reduce and / or prevent the loads from reaching the second body 3.

[0106] The joints 5 are connected between the first body 2 and the second body 3 to couple the first body 2 with the second body 3. The joints 5 isolate the second body 3 from the first body 2 by use of isolation layers. The joints 5 are a thermomechanical decoupler that connects the first body 2 and the second body 3. The joints 5 absorb at least a portion of the loads that come from the first body 2. The joints 5 are the only mechanisms that transfer force from the first body 2 to the second body 3.Further, the joints 5 may be an overconstrained mechanism. In other words, multiple joints 5 may constrain the same degrees of freedom. Having redundant constraints allows the first body 2 to provide extra stiffness to the second body 3. At the same time, the second body 3 is still isolated from the expected thermal and acceleration loads. As a result, the thermal-mechanical deformations and the acceleration loads produced by the motors 6 driving the first body 2 are reduced at the second body 3. The deformations created at the first body 2 are isolated from the second body 3. As a result, the loads generated at the first body 2 are reduced and prevented from being transmitted from the first body 2 to the second body 3. The isolation is primarily performed in the x- and y-directions, because joints 5 are less stiff in those directions.

[0107] The second body 3 is coupled to the first body 2 via the joints 5. The second body 3 is a metrology frame to which a reticle clamp 4 is attached. The reticle clamp 4 provides a force (e.g., electrostatic or vacuum force) to hold the patterning device MA to the chuck 1. As a result, thepatterning device MA is capable of withstanding the high accelerations of the chuck 1 to remain attached to the clamp 4. The reticle clamp 4 and scales and fiducials 7 are both positioned on the bottom side (or -z-side) of the second body 3. The reticle clamp 4 is held in the middle of the bottom side of the second body 3, while the scales and fiducials 7 are held at the periphery of the second body 3. The patterning device MA (see FIGS. 1A-1C) is clamped to the bottom side (or -z-side) of the reticle clamp 4 in FIG. 4.

[0108] The first body 2, or the force frame, is made from a material with a very good specific stiffness. In other words, the material has a high stiffness over density ratio. Further, the first body 2 has a higher stiffness to density ratio in comparison to the second body 3. As a result, the first body 2 provides extra stiffness to the second body 3 without disturbing its stability. Materials that fit this criterion include metal alloy and ceramic. For example, the first body 2 may comprise silicon carbide (SiC) or reaction bonded silicon carbide (SiSiC) possibly with some diamond content. The first body 2 can be any material that has a very good specific stiffness. Another material that may be used for the first body 2 is aluminum alloy, which sacrifices some performance for cost savings. A high stiffness is necessary to prevent the first body 2 from shattering when subjected to increased acceleration during exposure.

[0109] The second body 3, or the metrology frame, is made from a zero coefficient of thermal expansion (zero-CTE). Zero-CTE materials are desirable, because they keep the second body 3 flat and prevent deformations, expansion, or shrink in the xy-plane. Examples of materials that can be used for the second body 3 include ultra-low expansion (ULE) material, such as lithiumaluminosilicate glass-ceramic (Zerodur glass), or cordierite. ULE material is designed and formulated to exhibit essentially zero thermal expansion over a wide temperature range. As a result, thermal loads from the first body 2 will not alter the second body 3. Further, the second body 3 is minimized in volume and mass. It is just large enough to hold the reticle clamp 4 and the scales and fiducials 7. Further, the height of the second body 3 is reduced significantly to eliminate mass of the second body 3. Since the thickness of the second body 3 is small, it is reinforced by the stiffness of the first body 2 via the joints 5. As a result, the stiffness of the first body 2 secures the thin second body 3 to prevent it from wobbling or flexing.

[0110] The joints 5 may be made of a material that is the same material as the first body 2 or the second body 3. Specifically, the joints 5 may be constructed of ULE material (such as Zerodur glass) or cordierite to be the same material as the second body 3. As a result, the joints 5 may be integrated with the second body 3 such that the joints 5F are a part of the second body 3 (see FIG. 9B). When the joints 5 are integrally formed with the second body 3, the joints 5 are also attached to the first body 2. Alternatively, the joints 5 may be constructed of a material with a high specific stiffness like the first body 2, such as metal alloy, ceramic, SiC, or SiSiC with a percentage of diamond (for example, in one embodiment, 42% diamond). As a result, the joints 5 may be integrated with the first body 2 such that the joints 5 are a part of the first body 2. When the joints 5 are integrally formedwith the first body 2, the joints 5 are also attached to the second body 3. Making the joints 5 the same material as either that of the first body 2 or the second body 3 prevents hysteresis, microslip, and particle generation. Further, the joints 5 may be integrally molded from a glass or ceramic material together with one of either the first body 2 or the second body 3, and connected to the other of the first body 2 and the second body 3. In a further alternative embodiment, the joints 5E may be constructed separately from the first body 2 and the second body 3 (see FIG. 9A). While the joints 5 are separately formed from the first body 2 and the second body 3, the joints 5 are attached at one end to the first body 2 and at the other end to the second body 3. As a result, the joints 5 may be constructed of a different material from the first body 2 and the second body 3. Further, FIG. 4 shows that the number of the joints 5 that are used to connect the first body 2 to the second body 3 is two. However, the number of the joints 5 are not limiting. For example, FIG. 5 shows three joints 5A, FIG. 6 shows seven joints 5B, FIGS. 7 and 8 show four joints 5C and 5D, respectively, and FIGS. 9A and 9B show a plurality of joints 5E and 5F, respectively. The number of joints in the plurality of joints 5E and 5F may be up to 200 joints or more. In theory, one joint can connect the first body 2 to the second body 3, but in one example a minimum number of joints is three. Therefore, the number of the joints 5 may range from one to 200.

[0111] FIG. 4 shows that there are two motors 6, but this number is not limiting. There are one or more motors 6 to effect movement of the first body 2. There may be only one motor 6. Alternatively, there may be three or more motors 6. Further, the motors 6 may be reluctance actuators whose coils are positioned on the long stroke actuator. Alternatively, the motors 6 may comprise a solenoid, a piezoelectric actuator, a servo moto, a stepper motor, an electromagnetic motor, a pneumatic motor, a hydraulic motor, a linear actuator, a piezo stepper, or any combination thereof.

[0112] The first body 2 may have a weight of between 2 and 4 kg and in one embodiment, is approximately 3 kg. The motors 6 on the first body 2 may have a weight of between 2 and 3.2 kg and in one embodiment, is approximately 2.6 kg. The motors 6 comprise xz-movers having a weight of between 0.25 and 0.75 kg and in embodiment, is approximately 0.5 kg. The motors also comprise y- movers having a weight of being 1.5 and 2.7 kg and in one embodiment, is approximately 2.1 kg. The second body 3 may have a weight of between 1 and kg and in one embodiment, is approximately 2 kg. The reticle clamp 4 may have a weight of between 0.2 and 1.2 kg and in one embodiment, is approximately 0.7 kg. The scales and fiducials 7 may have a weight of between 0.2 and 1.2 kg and in one embodiment, is approximately 0.7 kg. As a result, the reticle chuck 1 weighs less than approximately 10 kg, of which the first body 2 and the second body 3 is a total of between 3 and 7 kg and in one embodiment, is approximately 5 kg. Consequently, the resulting reticle chuck 1 may reach acceleration speeds of 1000 m / s2, which is double or triple the acceleration of the conventional reticle chuck. This high acceleration is not only achieved by a low weight reticle chuck, but also by sufficient powerful and efficient actuators 6.

[0113] FIG. 5 is a schematic illustration of the joints 5A for the reticle chuck, according to asecond embodiment of the present disclosure. Three V, or also called A, joints 5A are shown coupled to the second body 3. One V joint comprises two wire flexures or struts, defining one degree of freedom each. Three V joints make an exact constrained connection in six degrees of freedom if the surface planes of the three V joints have two intersection lines. The first body 2 (not shown in FIG. 5) is coupled to the top parts of the joints 5A. The joints 5A act similarly to the joints 5 in FIG. 4. The V joints 5A act as isolation layers to dampen the loads from the first body 2 to the second body 3. The three V joints 5A exactly constrain relative translation and rotation between the first body 2 and the second body 3 along and about the x-, y-, and z-axes respectively. The 3-fold symmetric arrangement of the V joints 5A comprises a compliant coupling in the radial direction about a common thermal center, thereby minimizing stresses induced in the second body 3 by thermal expansion of the first body 2. With three V joints 5A, the joints 5A may be set at 120° from adjacent joints 5A. Other angles between adjacent joints may also be applied. The V joints 5A may be made of any material that the joints 5 are made of.

[0114] FIG. 6 is a schematic illustration of the joints 5B for the reticle chuck, according to a third embodiment of the present disclosure. Seven wire joints 5B are integrated in the first body 2 and coupled to the second body 3. The seven wire joints 5B may include 4 z-joints in the z-direction, 2 y- joints in a y-direction, and 1 x-joint in an x-direction. Each of the seven wire joints 5B constrains one degree of freedom. For example, each z-joint 5B constrains the degree of freedom in the z-direction. The fourth z-joint suppresses the torsion like a table on four legs. Consequently, the second body 3 is a little overconstrained with seven degrees of freedom fixed with respect to the first body 2. The joints 5B are designed such that the total stiffness in the coupled direction is 2 x 109N / m, which makes it possible to reach a 4 kHz eigenfrequency with a second body 3 of 4 kg. As a result, the joints 5B are compliant in the low-stiffness and decoupled directions with a stiffness of less than 1 x 107N / m, to isolate the second body 3 from small expansions and deformations of the first body 2. The seven wire joints 5B may be integrally formed with the first body 2. As a result, the seven wire joints 5B are made of the same material as that of the first body 2. The first body 2 (not shown in FIG. 6) may be coupled to the top parts of the z-joints 5B.

[0115] The reticle chuck 1 of the seven wire joints 5B embodiment may have a mass of between 10 and 15 kg and in one embodiment, approximately 12 kg. The first body 2 has a mass of between 2 and 4 kg and in one embodiment, approximately 2.9 kg, and the second body 3 has a mass of between 4 and 5 kg and in one embodiment, approximately 4.4 kg. Further, the short stroke in the x-direction is actuated from the center.

[0116] FIG. 7 is a schematic illustration of the joints 5C for the reticle chuck, according to a fourth embodiment of the present disclosure. Four sheet joints 5C are shown coupled to the second body 3. The four sheet joints 5C are used to connect the first body 2 to the second body 3. Each of the four sheet joints 5C constrains three degrees of freedom to the second body 3, Each sheet joint 5C constrains rotations about a vector orthogonal the plane of said sheet (1 degree of freedom), as well astranslations along the two directions parallel to the edges of said sheet (2 degrees of freedom), for a total of 3 degrees of freedom. For example, a sheet parallel to a yz-plane will constrain rotations about the x-direction and translations along the y- and z-directions. As a result, 12 degrees of freedom of the second body 3are constrained, meaning that there are six overconstraints. Further, the overconstrained mechanism allows the first body 2 to provide extra stiffness to the second body 3 while still isolating the second body 3 from the expected thermal and acceleration loads. The four sheet joints 5C may be spaced 90° apart from each other, as shown in FIG. 7. Specifically, the four sheet joints 5C are positioned at 0°, 90°, 180°, and 270°. Other angles between adjacent joints may also be applied. The four sheet joints 5C may be integrally formed with the first body 2 (not shown in FIG. 7). As a result, the sheet joints 5C may be made of any material as that of the first body 2.

[0117] FIG. 8 is a schematic illustration of the joints 5D for the reticle chuck, according to a fifth embodiment of the present disclosure. The four sheet joints 5D are similar to the four sheet joints 5C of FIG. 7 except for their positioning. The four sheet joints 5D are shown coupled to the second body 3. The four sheet joints 5D are used to connect the first body 2 to the second body 3. Each of the four sheet joints 5D constrains three degrees of freedom to the second body 3 Each sheet joint 5C constrains rotations about a vector orthogonal the plane of said sheet (1 degree of freedom), as well as translations along the two directions parallel to the edges of said sheet (2 degrees of freedom), for a total of 3 degrees of freedom. For example, a sheet parallel to a yz-plane will constrain rotations about the x-direction and translations along the y- and z-directions. As a result, 12 degrees of freedom of the second body 3are constrained, meaning that there are six overconstraints, suppressing more eigenmodes of the second body 3. Further, the overconstrained mechanism allows the first body 2 to provide extra stiffness to the second body 3 while still isolating the second body 3 from the expected thermal and acceleration loads. The four sheet joints 5D may be generally positioned at an angle of between 30° to 60° with respect to the x- and y-axis. In an embodiment, the four sheet joints 5D may be positioned at an angle of 45° with respect to the x- and y-axis. As a result, the four sheet joints 5D are positioned at 45°, 135°, 225°, and 315° as shown in FIG. 8. The placement of the joints 5D provide stiffness in the corners of the second body 3 where the scales 7 are extending. The four sheet joints 5D may be integrally formed with the first body 2 (not shown in FIG. 8). As a result, the sheet joints 5D may be made of any material as that of the first body 2.

[0118] The reticle chuck 1 of the four sheet joints 5C and 5D embodiments shown in FIGS. 7 and 8, respectively, may have a mass of between 8 and 12 kg and in one embodiment, approximately 9.4 kg. The first body 2 has a mass of between 2 and 3 kg and in one embodiment, approximately 2.4 kg, and the second body 3 has a mass of between 2 and 4 kg and in one embodiment, approximately 3.0 kg. Further, the short stroke in the x-direction is actuated from the outer sides.

[0119] Each of FIGS. 5-8 has been described with a certain number of joints 5A-5D, respectively. However, the number of joints in these embodiments is not limiting. In FIG. 5, the number of joints 5A is not limited to three. In FIG. 6, the number of joints 5B is not limited to seven. In FIGS. 7-8,the number of joints 5C-5D is not limited to four. More or less joints may be used in each of these embodiments.

[0120] FIG. 9A is a schematic illustration of the joints 5E for the reticle chuck, according to a sixth embodiment of the present disclosure. FIG. 9A shows a plurality of joints 5E that is materially different than the first body 2 and the second body 3. For example, the plurality of joints 5E may be made out of etched fused silica having a CTE of 0.5 ppm. Since the plurality of joints 5E is not integrated with the first body 2 or the second body 3, the plurality of joints 5E requires adhesive to connect to the two bodies. Adhesive 9 may be applied between the first body 2 and the plurality of joints 5E. Similarly, adhesive 9 may be applied on the other side between the second body 3 and the plurality of joints 5E. The adhesive 9 connecting the plurality of joints 5E to the first body 2 and to the second body 3 may be an epoxy. The plurality of joints 5E are consequently connected to the bottom surface of the first body 2 and the top surface of the second body 3. The plurality of joints 5E extend in the z-direction. As a result, the plurality of joints 5E each have a particular z-directional stiffness. The second body 3 of FIG. 9A will be further described below. The second body 3 has open spaces to reduce the mass of the second body 3.

[0121] FIG. 9B is a schematic illustration of the joints 5F for the reticle chuck, according to a seventh embodiment of the present disclosure. FIG. 9B shows a plurality of joints 5F that is integrated with a top surface of the second body 3. As a result, the material of the plurality of joints 5F is the same as that of the second body 3. For example, the plurality of joints 5F may be a Zerodur glass material. The joints 5F have a two-dimensional pattern in the xy-plane and are etched into the material of the second body 3. The first body 2 may be connected to the plurality of joints 5F by applying an adhesive 9. The adhesive 9 connecting the plurality of joints 5F to the first body 2 may be an epoxy. Similar to the plurality of joints 5E in FIG. 9A, the plurality of joints 5F extend in the z- direction. As a result, the plurality of joints 5F each have a particular z-directional stiffness. The second body 3 of FIG. 9B will be further described below. The second body 3 has open spaces to reduce the mass of the second body 3.

[0122] FIGS. 9 A and 9B show that the second body 3 has water cooling conduits 10 to provide cooling to the second body 3. By using cooling conduits 10, thermal loads may be mitigated. The thermal-mechanical deformations can be prevented by applying the cooling conduits 10 on the second body 3. In addition to the second body 3, the water cooling conduits may be provided to the first body 2. Additionally, temperature sensors (not shown) may be positioned at the first body 2 to monitor temperature gradients at the first body 2. FIG. 10 is a schematic illustration of the second body 3 for the reticle chuck 1, according to an embodiment of the present disclosure. In order to decrease the mass of the second body 3, much of the second body 3 is hollow. This lightweight hollow body is an integrally formed structure and created by milling or grinding pockets 11 in the glass-like material, such as ceramic, of the second body 3. By etching or using a waterjet, a two- dimensional structure can be created. Some examples of the milling or grinding pockets are shown as11 in FIG. 10. Thereafter, adding a tin solid top and bottom plate yields a stiff and hollowed lightweight closed box.

[0123] By integrating the joints 5F to the second body 3, there is a lower elastic modulus, which results in thicker joints 5F for the same stiffness, making the joints 5F more robust. The joints 5F now have a two-dimensional pattern and can be etched in the zero-CTE material, such as glass. The z -joints 5F are positioned all over the surface of the second body 3. As a result, the second body 3 can become relatively thin and lightweight, improving the dynamics. In this concept, the second body 3 base is 10 mm thick, making it more cost effective.

[0124] The reticle chuck 1 of the plurality of joints 5E and 5F embodiments shown in FIGS. 9A and 9B, respectively, may have a mass of between 7 and 10 kg and in one embodiment, approximately 8.8 kg. The first body 2 has a mass of between 2 and 4 kg and in one embodiment, approximately 2.9 kg, and the second body 3 has a mass of between 1 and 3 kg and in one embodiment, approximately 1.9 kg. Further, the short stroke in the x-direction is actuated from the outer sides.

[0125] By having the joints 5E and 5F of FIGS. 9A and 9B, respectively, cover the surface of the second body 3, that allows the second body 3 to become relatively thin and more lightweight, improving its dynamics. The second body 3 may have a thickness of between 5 and 30 mm. In an embodiment, the second body 3 is 10 mm thick.

[0126] FIGS. 9A and 9B describe the adhesive 9 to be an epoxy. However, the adhesive 9 is not limited to this. In an alternative embodiment, the adhesive 9 may be created by optical or chemical bonding. Further, the plurality of joints 5E and 5F in FIGS. 9A and 9B, respectively, may include between 50 to 400 joints. In an embodiment, the number of joints is 200. The joints 5E and 5F may be distributed evenly on the top surface of the second body 3. However, if the thermal and acceleration loads on the first body 2 are not even, then the joints 5E and 5F may be redistributed to compensate for the uneven loads. For example, if the left side of the first body 2 is subject to higher amounts of heat, then the plurality of joints 5E and 5F can be concentrated on the left side to mitigate thermal loads from reaching the second body 3.

[0127] Each of the joints 5A-5F described above may also be fine-tuned based on the thermal and acceleration loads. The joints 5A-5F may be machined having a higher or lower stiffness based on thermal and acceleration loads.

[0128] For any of the above embodiments, it is possible for there to be a releasable connection between the joints 5 and the second body 3, thus enabling other second bodies to be connected to the first body 2. For any embodiment where the joints 5 are not integrated into the second body 3, the releasable connection may be used to switch to another second body 3. Further, the second body 3 has a swappable clamp configuration. The lifetime of the reticle clamp 4 is much shorter (on the order of months) than that of the second body 3 (on the order of years). As a result, it is also possible to replace only the reticle clamp 4.

[0129] Additionally, the short stroke chuck assembly described above is made in reference to a reticle chuck. However, this is not limiting. The short stroke chuck assembly having a split chuck may be used for a substrate chuck.

[0130] The description above of the short stroke reticle chuck 1 is intended for an extreme ultraviolet (EUV) reticle chuck, but it is not limited to EUV short stroke chucks. Alternatively, the reticle chuck 1 may be used for deep ultraviolet (DUV) or other types of reticle chucks.

[0131] Various embodiments of the present systems and methods are disclosed in the subsequent list of numbered clauses:1. A object chuck, comprising: a first body having mounts enabling it to be operatively driven by one or more motors, the first body being subjected to thermal-mechanical deformations and acceleration loads as a result of being driven; a second body configured to support an object clamp; and joints coupling the first body with the second body, the joints reducing the thermal-mechanical deformations and the acceleration loads from being transmitted from the first body to the second body.2. The object chuck of any of the previous clauses, wherein the joints are integrally formed with the first body and attached to the second body.3. The object chuck of any of the previous clauses, wherein the joints are integrally formed with the second body and attached to the first body.4. The object chuck of any of the previous clauses, wherein the joints are separately formed from the first and second body and are attached to both the first body and the second body.5. The object chuck of any of the previous clauses, wherein the second body is made of a material having a zero coefficient of thermal expansion (CTE).6. The object chuck of any of the previous clauses, wherein the second body comprises ultra-low expansion material such as lithium-aluminosilicate glass-ceramic (Zerodur glass), or cordierite .7. The object chuck of any of the previous clauses, wherein the second body comprises lithiumaluminosilicate glass-ceramic.8. The object chuck of any of the previous clauses, wherein the second body comprises cordierite.9. The object chuck of any of the previous clauses, wherein the first body has a higher stiffness to density ratio in comparison to the second body.10. The object chuck of any of the previous clauses, wherein the first body comprises metal alloy or ceramic.11. The object chuck of any of the previous clauses, wherein each joint constrains 3 degrees of freedom of the second body.12. The object chuck of any of the previous clauses, wherein the joints are integrally molded from a glass or ceramic material together with one of either the first body or the second body, and connected to the other of the first body or the second body.13. The object chuck of any of the previous clauses, further comprising water cooling conduits on the first body and the second body14. The object chuck of any of the previous clauses, further comprising temperature sensors at the first body for monitoring temperature gradients at the first body.15. The object chuck of any of the previous clauses, wherein the second body is configured to hold fiducials and scales, and wherein the first body is configured to engage with motor actuators.16. The object chuck of any of the previous clauses, wherein four or more joints are used to connect the first body with the second body.17. The object chuck of any of the previous clauses, wherein seven wire joints are integrally formed with the first body.18. The object chuck of any of the previous clauses, wherein each joint constrains one degree of freedom.19. The object chuck of any of the previous clauses, wherein the joints comprise 4 z-joints, 2 x-joints, and 1 y-joint.20. The object chuck of any of the previous clauses, wherein the joints comprise four sheet joints integrated with the first body.21. The object chuck of any of the previous clauses, wherein the four sheet joints are generally positioned at the corners of the first body and wherein the sheet joints are generally disposed at an angle of between 30 to 60 degrees with respect to the x- and y-axis.22. The object chuck of any of the previous clauses, wherein the 4 sheet joints each constrain 3 degrees of freedom to the second body.23. The object chuck of any of the previous clauses, wherein the joints comprise a plurality of joints that each have a particular z-directional stiffness integrated with or connected with the top surface of the second body.24. The object chuck of any of the previous clauses, wherein the joints have a pattern in an xy-plane and are etched in material of the second body.25. The object chuck of any of the previous clauses, wherein the joints are connected to the first body by epoxy or chemical bonding.26. The object chuck of any of the previous clauses, further comprising a releasable connection between the joints and the second body, thus enabling other second bodies to be connected to the first body.27. The object chuck of any of the previous clauses, wherein the mounts on the first body are configured to connect the first body with a short stroke motor.28. The object chuck of any of the previous clauses, wherein the joints are the only mechanisms that transfer force from the first body to the second body.29. The object chuck of any of the preceding clauses, wherein the object chuck is a reticle chuck and the object clamp is a reticle clamp.

[0132] The concepts disclosed herein may be associated with any generic imaging system for imaging sub wavelength features, and may be especially useful with emerging imaging technologiescapable of producing increasingly shorter wavelengths. Emerging technologies already in use include EUV (extreme ultra violet), DUV lithography that is capable of producing a 193nm wavelength with the use of an ArF laser, and even a 157nm wavelength with the use of a Fluorine laser. Moreover, EUV lithography is capable of producing wavelengths within a range of 20-5nm by using a synchrotron or by hitting a material (either solid or a plasma) with high energy electrons in order to produce photons within this range.

[0133] While the concepts disclosed herein may be used for wafer manufacturing on a substrate such as a silicon wafer, it shall be understood that the disclosed concepts may be used with any type of manufacturing system, e.g., those used for manufacturing on substrates other than silicon wafers. In addition, the combination and sub-combinations of disclosed elements may comprise separate embodiments. For example, the cleaning system and / or method, and the associated lithography apparatus may comprise separate embodiments, and / or these features may be used together in the same embodiment.

[0134] The descriptions above are intended to be illustrative, not limiting. Thus, it will be apparent to one skilled in the art that modifications may be made as described without departing from the scope of the claims set out below.

Claims

CLAIMS1. An object chuck comprising: a first body having mounts enabling it to be operatively driven by one or more motors, the first body being subjected to thermal-mechanical deformations and acceleration loads as a result of being driven; a second body configured to support an object clamp; and joints coupling the first body with the second body, the joints reducing the thermalmechanical deformations and the acceleration loads from being transmitted from the first body to the second body.

2. The object chuck of claim 1, wherein the joints are integrally formed with the first body and attached to the second body, the joints are integrally formed with the second body and attached to the first body, or the joints are separately formed from the first and second body and are attached to both the first body and the second body.

3. The object chuck of claim 1, wherein the second body is made of a material having a zero coefficient of thermal expansion (CTE), the second body comprises ultra-low expansion material, the second body comprises lithium-aluminosilicate glass -ceramic, or the second body comprises cordierite.

4. The object chuck of any of claim 1, wherein: the first body has a higher stiffness to density ratio in comparison to the second body; the first body comprises metal alloy or ceramic; and each joint constrains 3 degrees of freedom of the second body.

5. The object chuck of claim 1, wherein the joints are integrally molded from a glass or ceramic material together with one of either the first body or the second body, and connected to the other of the first body or the second body.

6. The object chuck of claim 1, further comprising: water cooling conduits within the first body and / or the second body; and temperature sensors at the first body for monitoring temperature gradients at the first body.

7. The object chuck of claim 1, wherein: the second body is configured to hold fiducials and scales, and wherein the first body is configured to engage with motor actuators; andfour or more joints are used to connect the first body with the second body; and8. The object chuck of claim 1, wherein: seven wire joints are integrally formed with the first body; each joint constrains one degree of freedom; and the joints comprise 4 z-joints, 2 x-joints, and 1 y-joint.

9. The object chuck of claim 1, wherein: the joints comprise four sheet joints integrated with the first body. the four sheet joints are generally positioned at the corners of the first body and wherein the sheet joints are generally disposed at an angle of between 30 to 60 degrees with respect to the x- and y-axis; and the 4 sheet joints each constrain 3 degrees of freedom to the second body.

10. The object chuck of claim 1, wherein: the joints comprise a plurality of joints that each have a particular z-directional stiffness integrated with or connected with the top surface of the second body; the joints have a pattern in an xy-plane and are etched in material of the second body; and the joints are connected to the first body by epoxy or chemical bonding.

11. The object chuck of claim 1, further comprising a releasable connection between the joints and the second body, thus enabling other second bodies to be connected to the first body.

12. The object chuck of claim 1, wherein the mounts on the first body are configured to connect the first body with a short stroke motor.

13. The object chuck of claim 1, wherein the joints are the only mechanisms that transfer force from the first body to the second body.

14. The object chuck of claim 1, wherein the object chuck is a reticle chuck and the object clamp is a reticle clamp.

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