Cooling system for a linear actuator

Abstract

A cooling system for a linear actuator is described. The system includes a wound electrical coil and a cooling plate. The electrical coil is configured to be energized to provide an electromagnetic force to the linear actuator. The electrical coil is configured to surround an armature of the linear actuator. The cooling plate is in thermal contact with the electrical coil and is configured to cool the electrical coil. A plurality of individual cooling plates are configured to surround the armature and positioned between adjacent individual coils such that the electrical coils and the cooling plates form a series of alternating plates and coils along the length of the armature.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims priority to U.S. Application No. 63 / 422,717, filed on November 4, 2022, and the entire content of the U.S. application is incorporated herein by reference. Technical Field

[0003] This specification generally relates to a cooling system for a linear actuator. Background Art

[0004] Linear actuators are well - known. For example, multiphase electromagnetic linear actuators have been used as long - stroke actuators in lithographic apparatuses, metrology systems, and other devices. A lithographic (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) can comprise or provide a pattern corresponding to a single layer of an IC (“design layout”), and such a pattern can be transferred onto a target portion (e.g., including one or more dies) of a substrate (e.g., a silicon wafer) that has been coated with a layer of radiation - sensitive material (“resist”) by a method such as irradiating the target portion via the pattern on the patterning device. Generally, a single substrate includes a plurality of adjacent target portions to which patterns are successively transferred by the lithographic projection apparatus, one target portion at a time. In this type of lithographic projection apparatus, the pattern on the entire patterning device is transferred onto one target portion in one operation. Such a device is commonly referred to as a stepper. In an alternative device, commonly referred to as a step - and - scan device, the projection beam scans across the patterning device in a given reference direction (“scan” direction), while the substrate is moved synchronously parallel or anti - parallel to this reference direction. Different portions of the pattern on the patterning device are gradually transferred onto one target portion. Various movements of the lithographic apparatus can be effected by one or more linear actuators. Summary of the Invention

[0005] A cooling system for a linear actuator is described. The cooling system includes a wound electrical coil and a cooling plate. The electrical coil is configured to be energized to provide an electromagnetic force for the linear actuator. The electrical coil is configured to surround an armature of the linear actuator. The cooling plate is in thermal contact with the electrical coil and is configured to cool the electrical coil. A plurality of individual cooling plates are configured to surround the armature and are positioned between adjacent individual coils such that the electrical coils and the cooling plates form a series of alternating plates and coils along the length of the armature. Among other advantages, the electrical coil and the cooling plate are configured to be assembled piece by piece, where alternating wound electrical coils and cooling plates are coupled to each other to form the cooling system. Compared to a parallel orientation and / or integral construction of the plurality of wound electrical coils and the plurality of cooling plates, the generally vertical orientation of the electrical coils and the cooling plates relative to the length of the armature and / or the piece-by-piece separated nature of the electrical coils and the cooling plates are configured to reduce shear forces along the length of the armature on mechanical fasteners and / or adhesives that connect any two wound electrical coils and / or cooling plates. Additionally, for embodiments having a slotted ferromagnetic armature that serves as a back iron, the generally vertical orientation of the cooling plates relative to the length of the armature, compared to a parallel orientation of the cooling plates, is configured to reduce the distance between the magnets and the ferromagnetic back iron of the linear actuator. Further, the orientation of the electrical coils and the cooling plates in a plane perpendicular to the length of the armature is configured to resist undesired movement or deformation of the linear actuator. Other advantages are contemplated.

[0006] According to an embodiment, a system for a linear actuator is provided. The system includes a plurality of wound electrical coils configured to be energized to provide an electromagnetic force for the linear actuator. The plurality of wound electrical coils are configured to surround an armature of the linear actuator. The system includes a plurality of cooling plates in thermal contact with the plurality of wound electrical coils and configured to cool the plurality of wound electrical coils. Individual plates of the plurality of cooling plates are configured to surround the armature and are positioned between adjacent individual coils such that the plurality of wound electrical coils and the plurality of cooling plates form a series of alternating plates and coils along the length of the armature.

[0007] In some embodiments, the plurality of wound electrical coils and the plurality of cooling plates are configured to be oriented in a plane generally perpendicular to the length of the armature.

[0008] In some embodiments, the plurality of wound electrical coils and the plurality of cooling plates are configured to be assembled piece by piece, where alternating wound electrical coils and cooling plates are coupled to each other to form the cooling system.

[0009] In some embodiments, compared to the parallel orientation and / or overall structure of the plurality of wound electrical coils and the plurality of cooling plates, the generally vertical orientation of the plurality of wound electrical coils and the plurality of cooling plates relative to the length of the armature, and / or the piece-by-piece separation nature of the plurality of wound electrical coils and the plurality of cooling plates are configured to reduce the shear force along the length of the armature on mechanical fasteners and / or adhesives that couple any two wound electrical coils and / or cooling plates.

[0010] In some embodiments, compared to the parallel orientation of the plurality of cooling plates, the generally vertical orientation of the plurality of cooling plates relative to the length of the armature is configured to reduce the distance between the magnet and the ferromagnetic back iron of the linear actuator.

[0011] In some embodiments, the plurality of cooling plates have a generally rectangular cross-section having one or more cooling channels formed therein, the one or more cooling channels being configured to carry a coolant.

[0012] In some embodiments, the plurality of cooling plates are configured to be coupled together such that the one or more cooling channels carry the coolant to cool the plurality of wound electrical coils along the length of the armature.

[0013] In some embodiments, the plurality of cooling plates include regions having one or more cooling channels and / or electrical wiring in a plane, regions for bus wiring in a normal direction, and / or regions for mechanical coupling to the armature, another plate, and / or a coil.

[0014] In some embodiments, for example, the plurality of wound electrical coils are configured to be welded to each other via inner leads routed through grooves in the armature, and the locations of the grooves can be selected to minimize the air gap in the magnetic flux path through the armature.

[0015] In some embodiments, the plurality of wound electrical coils include outer leads configured to be coupled to another coil in series, to a junction between parallel phases, or to an amplifier.

[0016] In some embodiments, the inner leads, the outer leads, and / or the plurality of wound electrical coils are configured such that distributed phase currents are achieved through stacked windings.

[0017] In some embodiments, the inner leads, the outer leads, and / or the plurality of wound electrical coils are configured such that concentrated phase currents are achieved using stacked coils between the cooling plates.

[0018] In some embodiments, the system further includes an insulator and / or adhesive positioned between the plurality of wound electrical coils and the plurality of cooling plates.

[0019] In some embodiments, the insulator includes Kapton, a ceramic sheet, a nylon sheet, a Teflon sheet, or another corona-resistant polyimide. Generally, any material that can be used as an electrical insulator between the coil winding and the metal (as an example material) cooling plate can include the insulator. In some embodiments, the cooling plate itself can be an insulating ceramic material, and there can be some material between the cooling plate and the coil winding configured for thermal coupling.

[0020] In some embodiments, the coil and / or cooling plate material can be selected to optimize the match of the coefficient of thermal expansion along the length of the armature between the layers of the coil and the cooling plate.

[0021] In some embodiments, the plurality of wound electrical coils include surface-wound flat wire coils or toroidally-wound coils.

[0022] In some embodiments, the coil and plate stack is configured to be mechanically pre-loaded in the direction of movement of the linear actuator to eliminate the need for an adhesive and / or potting material between the coil and the coil housing for coupling the coil to the cooling plate during operation, thereby maintaining good thermal contact, and / or for other reasons.

[0023] In some embodiments, the system further includes a cladding surface configured to enclose the plurality of wound electrical coils, the plurality of cooling plates, and the armature.

[0024] In some embodiments, the linear actuator is a Lorentz actuator or a linear actuator having magnetic material in its armature, with or without slots or magnetic teeth in the armature.

[0025] In some embodiments, the length includes a portion or the full length of the armature.

[0026] In some embodiments, the cooling system and the linear actuator form part of a lithography apparatus or metrology apparatus configured for a semiconductor manufacturing process, or part of other apparatus that requires precise movement at high acceleration.

[0027] According to another embodiment, a cooling method for a linear actuator is provided. The method includes forming a plurality of wound electrical coils configured to be energized to provide an electromagnetic force for the linear actuator, the plurality of wound electrical coils being configured to surround an armature of the linear actuator. The method includes forming a plurality of cooling plates and positioning the plurality of cooling plates in thermal contact with the plurality of wound electrical coils, the plurality of cooling plates being configured to cool the plurality of wound electrical coils, wherein individual plates of the plurality of cooling plates are configured to surround the armature and are positioned between adjacent individual coils such that the plurality of wound electrical coils and the plurality of cooling plates form a series of alternating plates and coils along the length of the armature.

[0028] According to another embodiment, a lithographic apparatus configured for a semiconductor manufacturing process is provided. The lithographic apparatus includes a linear actuator and a cooling system for the linear actuator. The cooling system includes a plurality of wound electrical coils configured to be energized to provide an electromagnetic force for the linear actuator. The plurality of wound electrical coils are configured to surround an armature of the linear actuator. A plurality of cooling plates in thermal contact with the plurality of wound electrical coils are configured to cool the plurality of wound electrical coils. Individual plates of the plurality of cooling plates are configured to surround the armature and are positioned between adjacent individual coils such that the plurality of wound electrical coils and the plurality of cooling plates form a series of alternating plates and coils along the length of the armature. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments and, together with the description, explain these embodiments. Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which corresponding reference numerals indicate corresponding parts, and in which:

[0030] Figure 1 Schematically depicts a lithographic apparatus according to an embodiment that may include a linear actuator having this cooling system.

[0031] Figure 2 Schematically depicts an embodiment of a lithographic cell or cluster according to an embodiment that may include a linear actuator having this cooling system in one or more devices of the lithographic cell or cluster.

[0032] Figure 3 Illustrates an armature having surface wound electrical coils according to an embodiment as compared to an armature having racetrack-shaped wound coils.

[0033] Figure 4 Illustrates a phase current distribution configuration for a linear actuator according to an embodiment.

[0034] Figure 5 The figure shows an example three-phase current distribution configuration with a linear actuator track according to an embodiment.

[0035] Figure 6 The figure shows a cooling system for a linear actuator according to an embodiment.

[0036] Figure 7 The figure shows how a coil and plate stack according to an embodiment is configured to be mechanically pre-loaded in the moving direction of a linear actuator to eliminate the need for gluing and / or potting between the coil and the coil housing during operation to couple the coil to a cooling plate; and how a substantially vertical orientation of a plurality of cooling plates relative to the length of the armature is configured to reduce the distance between the magnet and the ferromagnetic back iron of the linear actuator as compared to a parallel orientation of the cooling plates.

[0037] Figure 8 The figure shows a cooling channel and / or a bushing actuator motor unit that traverses the length of the armature and is connected to a main inlet / outlet channel in a cooling plate according to an embodiment. Note that one or more cooling channels can take any path and need not be a straight path along the length of the coil winding. For example, the channel path can be optimized to ensure that each winding in the coil is superimposed with cooling water at a certain moment.

[0038] Figure 9 The figure shows how a plurality of surface-wound electrical coils and a plurality of cooling plates according to an embodiment are configured to be assembled piece by piece, wherein the alternating surface-wound electrical coils and cooling plates are coupled to each other to form the cooling system.

[0039] Figure 10 The figure shows a region of a coil / plate according to an embodiment that is configured for routing electrical connections through the volume between the cooling plates and penetrating the cross-section of the cooling plates.

[0040] Figure 11 The figure shows an example three-phase press-in unit with a distributed current distribution according to an embodiment.

[0041] Figure 12 The figure shows an example three-phase press-in unit with a centralized and distributed current distribution according to an embodiment.

[0042] Figure 13 The figure shows a cooling method for a linear actuator according to an embodiment. Detailed Description

[0043] Two different types of multiphase electromagnetic linear actuators have been used as long-stroke actuators in lithographic apparatuses, metrology systems, and other devices. For example, Lorentz actuators, linear actuators with magnetic material present in their armatures (with or without slots or magnetic teeth in the armature), and / or other motion systems are used in lithographic apparatuses (e.g., these can also be referred to as slotted-core LPMSMs (linear permanent magnet synchronous motors)). A relatively high acceleration of the lithographic apparatus platform is required. A higher platform acceleration increases the throughput of the lithographic apparatus, resulting in a lower cost per die (or per microchip).

[0044] However, a relatively high platform acceleration results in increased dynamic loads and increased thermal loads in the current linear actuators used in lithographic apparatuses. The increased dynamic and thermal loads may lead to a catastrophic temperature increase in the linear actuator coils and / or an overall failure of the actuator motor, resulting in an increased demand on the amplifier and, depending on the design, a greater degree of saturation of the soft magnetic material present in the magnetic circuit of the linear actuator. It is known that due to the heat dissipation effect or the thermal runaway effect, the increased thermal load reduces the efficiency or the actuator (the resistance increases at higher temperatures, and the more power is consumed at higher resistance, the more heat is thus generated by the coil, which further raises their temperature). It is generally believed that a catastrophic failure of the coil winding occurs when the coil temperature exceeds the wire insulation rating. These factors limit the force density (in [N / kg]) that can be achieved by the linear actuator and thus limit the achievable peak acceleration ([N / kg] = [m / s2]) of the lithographic apparatus platform. For example, three-phase Lorentz actuators using moving magnets or moving coils are currently used in many lithographic apparatuses. Lorentz actuators are sometimes favored because they produce less vibration and less general non-linear behavior compared to other linear actuators. However, Lorentz actuators are relatively inefficient compared to other linear actuators, thus requiring more average power from the amplifier.

[0045] A new cooling system for a linear actuator is described below. The new cooling system includes a wound electrical coil and a cooling plate. The electrical coil and the cooling plate are configured to surround an armature of the linear actuator, wherein a plurality of individual cooling plates are positioned between adjacent individual coils such that the electrical coils and the cooling plates form a series of alternating plates and coils along the length of the armature. Advantageously, this design allows for the electrical coil and the cooling plate to be assembled piece by piece, wherein the alternating wound electrical coils and cooling plates are coupled to each other to form the cooling system. Compared to a parallel orientation and / or an integral structure of a plurality of wound electrical coils and a plurality of cooling plates, the generally vertical orientation of the electrical coils and the cooling plates with respect to the length of the armature and / or the piece-by-piece separated nature of the electrical coils and the cooling plates are configured to reduce shear forces along the length of the armature on mechanical fasteners and / or adhesives that couple any two wound electrical coils and / or cooling plates (e.g., in the previously described prior linear actuator). Additionally, compared to a parallel orientation of the cooling plates, the generally vertical orientation of the plurality of cooling plates with respect to the length of the armature is configured to reduce the distance between the magnets and the ferromagnetic back iron of the linear actuator. Further, the orientation of the electrical coils and the cooling plates in a plane perpendicular to the length of the armature is configured to resist undesired movement or deformation of the linear actuator. Accordingly, a linear actuator having the linear cooling system described below is more efficient than a prior linear actuator, and thus requires reduced average power from an amplifier compared to a prior linear actuator. Compared to a prior linear actuator, this allows such a linear actuator to achieve a higher force density (limited by coil temperature or amplifier limits), and thus achieve a higher peak acceleration of a lithography equipment platform.

[0046] The following introductory paragraph describes general lithography system functionality - as one of many possible use case examples of one or more linear actuators described herein. Note that while the manufacture of integrated circuits (ICs) may be specifically referenced herein, it should be understood that the described cooling system has many other possible applications. For example, it can be used in the manufacture of integrated optical systems, guiding and detecting patterns for magnetic domain memories, liquid crystal display panels, thin film magnetic heads, etc.

[0047] As an introduction, before transferring a pattern from a patterning device such as a mask to a substrate, the substrate may undergo various processes such as priming, resist coating, and soft baking. After exposure, the substrate may undergo other processes ("post-exposure processes") such as post-exposure bake (PEB), development, hard bake, and measurement and / or other inspection of the transferred pattern. Such an array of processes serves as the basis for manufacturing a single 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 of which are aimed at finishing the single layer of the device. If a certain number of layers are required in the device, the entire process or a variant thereof is repeated for each layer. Eventually, there will be devices in each target portion on the substrate. These devices are then separated from each other by techniques such as dicing or sawing, and the individual devices can then be mounted on a carrier, connected to pins, etc.

[0048] Manufacturing devices such as semiconductor devices typically involves using a large number of fabrication processes to process a substrate (e.g., a semiconductor wafer) to form various features and multiple layers of the device. Such layers and features are typically fabricated and processed using, for example, deposition, lithography, etching, chemical mechanical polishing, ion implantation, and / or other processes. Multiple devices can be fabricated on multiple die on a substrate, and the devices are then separated into individual devices. Such a device fabrication process can be regarded as a patterning process. The patterning process involves a patterning step using a patterning device in a lithography apparatus (such as optical and / or nanoimprint lithography) to transfer the pattern on the patterning device to the substrate, and typically but optionally involves one or more associated pattern processing steps such as resist development by a development apparatus, baking the substrate using a baking tool, etching using the pattern using an etching apparatus, etc. Typically, one or more metrology processes are involved in the patterning process. The lithography apparatus, metrology system, and other equipment used for manufacturing semiconductor devices can use one or more linear actuators having the described cooling system.

[0049] Lithography is a step in the manufacture of devices such as ICs, where the pattern formed on the substrate defines the functional elements of the device, such as microprocessors, memory chips, etc. Similar lithography techniques are also used to form flat panel displays, microelectromechanical systems (MEMS), and other devices.

[0050] Figure 1Embodiments are schematically depicted that may include one or more linear actuators and corresponding cooling systems and / or a lithographic apparatus LA associated with one or more linear actuators and corresponding cooling systems. The apparatus includes: an illumination system (illuminator) IL configured to condition a radiation beam B (e.g., UV radiation, DUV radiation, or EUV radiation); a support structure (e.g., a mask table) MT configured to support a patterning device (e.g., a mask) MA and connected to a first positioner PM configured to accurately position the patterning device according to certain parameters; a substrate table (e.g., a wafer table) WT (e.g., WTa, WTb, or both), the substrate table being configured to hold a substrate (e.g., a wafer coated with resist) W and coupled to a second positioner PW configured to accurately position the substrate according to certain parameters; and a projection system (e.g., a refractive projection lens 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 and often referred to as a field) of the substrate W. The projection system is supported on a reference frame (RF). As depicted, the apparatus is of the transmissive type (e.g., using a transmissive mask). Alternatively, the apparatus may be of the reflective type (e.g., using a programmable mirror array of the type mentioned above, or using a reflective mask).

[0051] The illuminator IL receives the radiation beam from a radiation source SO. For example, when the source is an excimer laser, the source and the lithographic apparatus may be separate entities. In such a case, the source is not considered to form part of the lithographic apparatus, and the radiation beam is transmitted from the source SO to the illuminator IL by means of a beam delivery system BD including, for example, suitable directing mirrors and / or beam expanders. In other cases, for example, when the source is a mercury lamp, the source may be an integral part of the apparatus. The source SO and the illuminator IL together with the beam delivery system BD (when required) may be referred to as the radiation system.

[0052] The illuminator IL may vary 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 within an annular region in the pupil plane of the illuminator IL is non-zero. 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 within a plurality of equally spaced segments in the pupil plane is non-zero. The intensity distribution of the radiation beam in the pupil plane of the illuminator IL may be referred to as the illumination mode.

[0053] The illuminator IL may include an adjuster AD configured to adjust the (angular / spatial) intensity distribution of the beam. Generally, at least the outer radial extent and / or the inner radial extent of the intensity distribution in the pupil plane of the illuminator can be adjusted (commonly referred to as σ - outer and σ - inner, respectively). The illuminator IL is operable to vary the angular distribution of the beam. For example, the illuminator is operable to change the number and angular extent of the segments in the pupil plane in which the intensity distribution is non - zero. By adjusting the intensity distribution of the beam in the pupil plane of the illuminator, different illumination patterns can be achieved. For example, by restricting the radial extent and angular extent of the intensity distribution in the pupil plane of the illuminator IL, the intensity distribution can have a multipole distribution, such as, for example, a bipolar, quadrupole, or hexapole distribution. The illumination pattern can be obtained, for example, by inserting optics that provide the desired illumination pattern into the illuminator IL or by using a spatial light modulator.

[0054] The illuminator IL is operable to change the polarization of the beam and is operable to adjust the polarization using the adjuster AD. The polarization state of the radiation beam across the pupil plane of the illuminator IL can be referred to as the polarization pattern. Using different polarization patterns can utilize a greater contrast in the image formed on the substrate W. The radiation beam can be unpolarized. Alternatively, the illuminator can be arranged to linearly polarize the radiation beam. The polarization direction of the radiation beam can vary across the pupil plane of the illuminator IL. The polarization direction of the radiation can be different in different regions of the pupil plane of the illuminator IL. The polarization state of the radiation can be selected depending on the illumination pattern. For a multipole illumination pattern, the polarization of each pole of the radiation beam can be substantially perpendicular to the position vector of the pole in the pupil plane of the illuminator IL. For example, for a bipolar illumination pattern, the radiation can be linearly polarized in a direction substantially perpendicular to the line bisecting the two opposite segments of the bipolar. The radiation beam can be polarized in one of two different orthogonal directions that can be referred to as the X - polarization state and the Y - polarization state. For a quadrupole illumination pattern, the radiation in each pole segment can be linearly polarized in a direction substantially perpendicular to the line bisecting the segment. This polarization pattern can be referred to as XY polarization. Similarly, for a hexapole illumination pattern, the radiation in each pole segment can be linearly polarized in a direction substantially perpendicular to the line bisecting the segment. This polarization pattern can be referred to as TE polarization.

[0055] In addition, the illuminator IL generally includes various other components, such as an integrator IN and a condenser CO. The illumination system can include various types of optical components for guiding, shaping, or controlling the radiation, such as refractive, reflective, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof. Thus, the illuminator provides a conditioned radiation beam B having a desired uniformity and intensity distribution in its cross - section.

[0056] The support structure MT supports the patterning device in a manner that depends on the orientation of the patterning device, the design of the lithographic apparatus, and other conditions, such as for example whether the patterning device is held in a vacuum environment. The support structure may use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterning device. The support structure may be, for example, a frame or a table, which may be fixed or movable as required. The support structure can ensure that the patterning device is, for example, in a desired position relative to the projection system.

[0057] The lithographic apparatus may be of a type having two (dual stage) or more stages (e.g., two or more substrate stages WTa, WTb, two or more patterning device stages, a substrate stage WTa and a stage WTb under the projection system without a substrate dedicated for, e.g., facilitating measurement and / or cleaning, etc.). In such a “multi-stage” machine, additional stages may be used in parallel, or preparatory steps may be carried out on one or more stages while one or more other stages are used for exposure. For example, alignment measurements using an alignment sensor AS and / or leveling (height, tilt, etc.) measurements using a leveling sensor LS may be performed.

[0058] In operation of the lithographic apparatus, the radiation beam is conditioned and provided by the illumination system IL. The radiation beam B is incident on a patterning device (e.g., a mask) MA held on a support structure (e.g., a mask table) MT. After traversing the patterning device MA, the radiation beam B passes through the projection system PS, which focuses the beam onto a target portion C of the substrate W. By means of a second positioner PW and a position sensor IF (e.g., an interferometric device, a linear encoder, a 2D encoder or a capacitive sensor), the substrate stage WT can be accurately moved, for example to position different target portions C in the path of the radiation beam B. Similarly, a first positioner PM and another position sensor (which is not shown in Figure 1(as depicted explicitly in []) can be used to accurately position the patterning device MA, for example, relative to the path of the radiation beam B after mechanical retrieval from the mask library or during scanning. Generally, movement of the support structure MT can be achieved by means of a long-stroke module (coarse positioning) and a short-stroke module (fine positioning) forming part of the first positioner PM. Similarly, movement of the substrate table WT can be achieved using a long-stroke module and a short-stroke module forming part of the second positioner PW. In the case of a stepper (relative to a scanner), the support structure MT can be connected only to the short-stroke actuator or can be fixed. Patterning device alignment marks M1, M2 and substrate alignment marks P1, P2 can be used to align the patterning device MA and the substrate W. Although the illustrated substrate alignment marks occupy dedicated target portions, the marks can be located in the spaces between the target portions (these marks are known as scribe alignment marks). Similarly, in the case where more than one die is provided on the patterning device MA, the patterning device alignment marks can be located between the dies.

[0059] The described apparatus can be used in at least one of the following modes: 1. In the step mode, when the pattern imparted to the radiation beam is projected onto the target portion C in one go, the support structure MT and the substrate table WT are kept substantially stationary (i.e., single static exposure). Subsequently, the substrate table WT is displaced in the X and / or Y direction so that different target portions C can be exposed. In the step mode, the maximum size of the exposure field is limited to the size of the target portion C imaged in a single static exposure. 2. In the scan mode, when the pattern imparted to the radiation beam is projected onto the target portion C, the support structure MT and the substrate table WT are scanned synchronously (i.e., single dynamic exposure). The speed and direction of the substrate table WT relative to the support structure MT can be determined by the magnification (reduction ratio) and image inversion characteristics of the projection system PS. In the scan mode, the maximum size of the exposure field is limited to the width (in the non-scanning direction) of the target portion in a single dynamic exposure, while the length of the scanning movement determines the height (in the scanning direction) of the target portion. 3. In another mode, when the pattern imparted to the radiation beam is projected onto the target portion C, the support structure MT is kept substantially stationary so as to hold the programmable patterning device, and the substrate table WT is moved or scanned. In this mode, a pulsed radiation source is typically used, and the programmable patterning device is updated as required after each movement of the substrate table WT or between successive radiation pulses during scanning. This operating mode can be readily applied in maskless lithography using a programmable patterning device such as a programmable mirror array of the type mentioned above. Combinations and / or variations of the usage modes described above or completely different usage modes can also be used.

[0060] The substrate may be processed before or after exposure, for example, in a track or a coat develop system (a tool that typically applies a resist layer to a substrate and develops the exposed resist) or a metrology or inspection tool. Any or all of these tools may include a linear actuator with a corresponding cooling system.

[0061] The various patterns on or provided by the patterning device may have different process windows. That is, the space of process variables according to which a pattern will be produced within specifications. Examples of pattern specifications regarding potential systematic defects include checking for necking, line pullback, line thinning, critical dimension (CD), edge placement, overlay, resist top loss, resist undercut, and / or bridging. The process window for a pattern on or of a patterning device or region thereof can be obtained by combining the process windows of each individual pattern (for example, by overlaying the process windows). The boundaries of the process window for a set of patterns include the boundaries of the process windows of some of the individual patterns. In other words, these individual patterns limit the process window for the set of patterns.

[0062] As Figure 2 shown, the lithographic apparatus LA may form part of a lithography cell LC (sometimes also referred to as a lithocell or cluster), which also includes equipment for performing pre-exposure processes and post-exposure processes on a substrate. Conventionally, this equipment includes one or more spin coaters SC for depositing one or more resist layers, one or more developers for developing the exposed resist, one or more chill plates CH, and / or one or more bake plates BK. A substrate transfer device or robot RO picks up one or more substrates from input / output ports I / O1, I / O2, moves the substrates between different process equipment, and transfers them to the feed table LB of the lithographic apparatus. These devices, often collectively referred to as a track or coat develop system, are controlled by a track or coat develop system control unit TCU, which itself is controlled by a management control system SCS, which also controls the lithographic apparatus via a lithography control unit LACU. Thus, the different devices can be operated to maximize throughput and processing efficiency.

[0063] In order to correctly and consistently expose the substrate exposed by the lithographic apparatus and / or to monitor part of a patterning process (such as a device manufacturing process) that includes at least one pattern transfer step (for example, an optical lithography step), it is desirable to detect the substrate or other object to measure or determine one or more properties, such as alignment, overlay (which may be, for example, between structures in an overlaying layer or between structures in the same layer that have been separately provided to the layer by, for example, a double patterning process), line thickness, critical dimension (CD), focus offset, material properties, etc.

[0064] One or more measured parameters can include, for example, alignment, overlap between successive layers formed in or on a patterned substrate, critical dimension (CD) (e.g., critical linewidth) of features formed in or on a patterned substrate, focus or focus error of an optical lithography step, dose or dose error of an optical lithography step, optical aberration of an optical lithography step, etc. Such measurements can be performed on targets of the product substrate itself and / or on dedicated metrology targets disposed on the substrate. The measurements can be performed after resist development but before etching, after etching, after deposition, and / or at other times.

[0065] There are various techniques for measuring structures formed during a patterning process, including using a scanning electron microscope, an image-based measurement tool, and / or various dedicated tools. Any or all of these tools can include a linear actuator with a corresponding cooling system. A fast and non-invasive form of dedicated metrology tool is a measurement tool in which a radiation beam is directed onto a target on the surface of a substrate and the properties of the scattered beam (diffracted beam / 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 can be referred to as diffraction-based metrology. One such application of this diffraction-based metrology is in the measurement of feature asymmetry within a target. The measurement of such feature asymmetry can be used as, for example, a measurement of overlap, but other applications are also known. For example, asymmetry can be measured by comparing relative portions of diffraction spectra (e.g., comparing the -1st order with the +1st order in the diffraction spectrum of a periodic grating).

[0066] The metrology results can be provided directly or indirectly to a supervisory control system SCS. If an error is detected, the exposure of subsequent substrates (especially in cases where the inspection can be completed quickly enough such that one or more other substrates of the batch are still to be exposed) and / or the subsequent exposure of the exposed substrates can be adjusted. In addition, the exposed substrates can be stripped and reworked to improve yield, or discarded, thereby avoiding further processing of substrates known to be defective. In cases where only some target portions of a substrate are defective, further exposure can be performed only on those target portions that meet the specifications.

[0067] This cooling system and / or method can be used as a stand-alone tool and / or technique, and / or in combination with semiconductor manufacturing equipment and / or processes, to enhance the accurate transfer of complex designs to physical wafers. For example, this cooling system can be an exposure apparatus including Figure 1 shown in Figure 2Parts of a linear actuator in one or more devices of the lithography unit shown and / or included in other devices (related semiconductor or non-semiconductor). As described above, the present cooling system includes a surface-wound electric coil and a cooling plate. The electric coil is configured to be energized to provide an electromagnetic force for the linear actuator. The electric coil is configured to surround the armature of the linear actuator. The cooling plate is in thermal contact with the electric coil and is configured to cool the electric coil. A plurality of individual cooling plates are configured to surround the armature and are positioned between a plurality of adjacent individual coils such that the electric coils and the cooling plates form a series of alternating plates and coils along the length of the armature.

[0068] Figures 3 to 5 Provides a basic description of various terms related to linear actuators. For example, Figure 3 Illustrates an armature 300 having a surface-wound electric coil 302 compared to an armature 350 having a racetrack-wound coil 352. The surface-wound electric coil 302 includes a coil having windings around the armature 300 (around the y-axis in this example). The racetrack-wound coil 352 has windings on the surface of the armature 350 (around the z-axis in this example). Figure 3 Illustrates a racetrack-wound coil 352 surrounding a core 354. The core 354 may include a soft ferromagnetic material and / or other materials. In some embodiments, the racetrack-wound coil 352 and the corresponding core 354 may be coupled to the surface of the armature 350 ( Figure 3 the top plane of the armature 350 in parallel to the xy plane) and / or some other surface (which may then be used as the armature providing mechanical support). Figure 3 The dashed circles 375 in indicate that the windings or current leave the page, where the crossed circles 385 indicate that the windings or current enter the page. The armature 300 and / or 350 may include structural members configured to mechanically support the surface-wound electric coil 302 or the racetrack-wound coil 352, the cooling plates (described below), and / or other components. The armature 300 and / or 350 may form part of a linear actuator that includes a main current-carrying winding (e.g., coil 302 or 352) and in which an electromotive force is induced. The armature 300 and / or 350 may include, for example, a soft ferromagnetic material and / or other materials.

[0069] Figure 4 Illustrates a phase current distribution configuration for a linear actuator. Figure 4 Illustrates a concentrated phase current 400 and a distributed phase current 402 (for N phases). Figure 4 Illustrates a surface-wound coil 302 of an armature 300 and a racetrack-wound coil 352 of an armature 350 (shown in the yz plane). Figure 4Illustrate the N-phase coil pitches 404, 406, 408, and 410. For the concentrated phase current 400, the current of each phase has adjacent + / -x current directions. For the distributed phase current 402, the current of each phase has spatially distributed + / -x current directions. A linear actuator in a lithographic apparatus can use a racetrack-wound coil 352 with a concentrated phase current 400 as a plunger (lower left box, note that the coil will be clamped between cooling plates oriented in the xy plane). This cooling system enables both a concentrated winding configuration and a distributed winding configuration for the surface-wound coils ( Figure 4 top row) in the linear actuator.

[0070] Figure 5 Illustrate an example of a three-phase current distribution configuration with linear actuator tracks 500 and 502. Figure 5 Illustrate the concentrated phase current 400 configuration and the distributed phase current 402 configuration for a surface-wound coil 302 with an armature 300 and a racetrack-wound coil 352 with an armature 350. Track 500 has a magnet pitch 510 different from the coil pitch 512 (a 2:1 pitch ratio (coil to magnet ratio)), while track 502 has the same magnet pitch 520 as the coil pitch 522 ("full pitch" distributed phase current). Note that Figure 5 these are merely examples, and many other configurations are possible (e.g., number of phases per actuator ≥ 3; pitch ratios other than 1:1 or 2:1; number of polarizations per magnet pitch in a Halbach array ≥ 2 and ≠ 4, etc.). Additionally, linear actuator motors with surface-wound coils are typically bilateral, i.e., double-sided (with two tracks), to utilize both the top and bottom current distributions. The surface-wound configuration requires a 180-degree phase shift in the magnet polarization between the upper and lower tracks.

[0071] Figure 6FIG. illustrates a cooling system 600 for a linear actuator according to an embodiment. The linear actuator may be a Lorentz actuator, a linear actuator having magnetic material in an armature (with or without slots or magnetic teeth), and / or other linear actuators. The cooling system 600 and the linear actuator may form part of, for example, a lithography apparatus or a metrology apparatus configured for a semiconductor manufacturing process, and / or may have other applications. Previous linear actuators in such devices typically included coils and / or cooling plates oriented "horizontally" (substantially parallel to the top or bottom surface of the armature). In contrast, the system 600 includes a cooling system having coils and cooling plates oriented "vertically" (substantially perpendicular to the top or bottom surface of the armature). Benefits of this orientation include rigid support for the coils, additional cooling surfaces relative to previous linear actuators, and design freedom for wire electrical connections for a wide range of phase current distributions, which may be beneficial for achieving high force density and reduced force ripple.

[0072] The system 600 includes a plurality of surface-wound electrical coils 602 configured to be energized to provide an electromagnetic force for the linear actuator. The surface-wound electrical coils 602 may be, for example, flat wire coils and / or other coils. The surface-wound electrical coils 602 may be formed of copper and / or other materials. The plurality of surface-wound electrical coils 602 are configured to surround the armature 604 of the linear actuator. The plurality of surface-wound electrical coils 602 may include, for example, surface-wound flat wire coils or toroidally-wound coils. Figure 6 Also illustrated are magnetic tracks 630, 632 on either side (above and below) of the surface-wound electrical coils 602 and the armature 604 of the linear actuator. In this embodiment, the pitch of the magnetic tracks 630 and 632 matches the width 634 of the pitch of the surface-wound electrical coils 602.

[0073] System 600 includes a plurality of cooling plates 610 in thermal contact with a plurality of surface-wound electrical coils 602. The cooling plates 610 are coupled 638 to the armature 604, the surface-wound electrical coils 602, and / or other components. This coupling 638 can be considered, for example, lamination (e.g., laminating the cooling plates 610). The cooling plates 610 are configured to rigidly fasten to the armature 604, resulting in mechanical rigid support of the surface-wound electrical coils 602 along the drive and normal directions of the linear actuator. The cooling plates 610 are configured to cool the plurality of surface-wound electrical coils 602. A plurality of individual plates among the plurality of cooling plates 610 are configured to surround the armature 604 and be positioned between adjacent individual coils 602 such that the plurality of surface-wound electrical coils 602 and the plurality of cooling plates 610 form a series 620 of alternating plates 610 and surface-wound electrical coils 602 along the length of the armature 604. The length includes, for example, a portion or the full length of the armature 604. Note that the cooling plates 610 are configured to be in thermal contact with the edges of the coils 602 (e.g., each winding is in direct contact with the surface of the cooling plate 610).

[0074] As Figure 6 shown, the plurality of cooling plates 610 have a generally rectangular cross-section 640 that has one or more cooling channels 642 configured to carry coolant. Note that the cooling plates 610 can have any cross-sectional shape and / or any number of channels 642, and the channels 642 are oriented in any configuration that allows them to function as described herein. The plurality of cooling plates 610 are configured to be coupled together such that one or more cooling channels 642 carry the coolant to cool the plurality of surface-wound electrical coils 602 along the length of the armature 604. The plurality of cooling plates 610 include regions 644 having one or more cooling channels 642 and / or electrical wiring in a plane, regions for bus wiring in the normal direction, and / or regions for mechanical coupling to the armature 604, another plate 610, and / or the surface-wound electrical coils 602.

[0075] In some embodiments, the plurality of surface-wound electrical coils 602 are configured to be welded to each other via inner leads 650 routed through slots 652 in the armature 604 and / or otherwise coupled to each other. Adjacent surface-wound electrical coils 602 can have opposite or the same winding directions depending on the configuration. The plurality of surface-wound electrical coils 602 also include outer leads 654 configured to be coupled to, for example, another surface-wound electrical coil 602 in series, a junction between parallel phases, or an amplifier.

[0076] In some embodiments, system 600 includes an insulator 660 and / or an adhesive 661 positioned between the plurality of surface-wound electrical coils 602 and the plurality of cooling plates 610. The insulator 660 can include Kapton, ceramic sheets, nylon sheets, Teflon sheets, and / or any other anti-corona polyimide. Generally, any material that can be used as an electrical insulator between a coil winding and a metal (as an example material) cooling plate can include the insulator. In some embodiments, the cooling plate itself can be an insulating ceramic material, and there can be some material between the cooling plate and the coil winding configured for thermal coupling.

[0077] In some embodiments, system 600 includes a cover and / or canning surface 670 configured to enclose the plurality of surface-wound electrical coils 602, the plurality of cooling plates 610, the armature 604, and / or other components of system 600. The canning surface can also provide additional mechanical support for one or more components of system 600. The canning surface can be a corrosion-resistant material similar to stainless steel (and also non-magnetic). The purpose of the canning surface is to prevent ferromagnetic materials from embrittling due to chemical reactions. For example, the shell can be a welded box or can be deposited in some way.

[0078] As Figure 6As shown, a plurality of surface-wound electrical coils 602 and a plurality of cooling plates 610 are configured to be oriented in a plane substantially perpendicular to the length of the armature 604. The plurality of surface-wound electrical coils 602 and the plurality of cooling plates 610 are configured as discrete components. Compared to a parallel orientation and / or a monolithic structure of the plurality of surface-wound electrical coils 602 and the plurality of cooling plates 610, the substantially vertical orientation of the plurality of surface-wound electrical coils 602 and the plurality of cooling plates 610 relative to the length of the armature 604, and / or the discrete nature of the plurality of surface-wound electrical coils 602 and the plurality of cooling plates 610 are configured to reduce shear forces along the length of the armature 604 on mechanical fasteners and / or adhesives (e.g., 661) that couple any two of the surface-wound electrical coils 602 and / or cooling plates 610. A glue layer may hold the coils in place and / or perform other functions. Functionally, the glue layer does more than just hold the coils in place. The glue layer can serve as a viscoelastic coupling between two parts (the coil and the insulating cooling plate) of the system having different coefficients of thermal expansion (CTE) but still needing to transfer forces to each other. Even in cases where the coil and the cooling plate grow and shrink by different amounts during force and thermal cycling due to their CTE mismatch, the viscoelastic nature of the glue layer still allows for mechanical and thermal coupling. The glue layer can also serve as additional protection against breakdown between the coil and an optional metal cooling plate by eliminating voids (filling all negative space in the coil / thermal gap volume helps with this). In examples optionally including a glue layer for the present system, the benefits of the viscoelastic coupling will still exist, rather than simply holding the coils in place. Attempting to obtain these benefits will come at the expense of the claimed performance improvements and will thus be a designer's choice (and thus, optional).

[0079] Figure 7 Illustrates how the laminated stack 700 of the surface-wound electrical coils 602 and the plates 610 is configured to be mechanically preloaded 702 in the direction of movement 704 of the linear actuator to reduce and / or eliminate the need for gluing and / or potting between the coils 602 and the coil housing (which can optionally be included in the Figure 6 system 600 shown) to couple the coils to the cooling plates ( Figure 7 showing a reaction force 710). Compared to a parallel orientation of the plurality of cooling plates 610, the substantially vertical orientation of the plurality of cooling plates 610 relative to the length of the armature 604 is configured to reduce the distance D between the magnetic tracks 630 of the linear actuator and the plurality of surface-wound electrical coils 602 (as in prior systems including a laminated stack of coils and cooling plates).

[0080] Figure 8Illustrated are the cooling channels 642 (in the xz plane in this figure) that are connected to the main inlet 800 / exit 802 channels (entering / leaving the page) in the cooling plate 610 and traverse the length of the armature 604, and / or the motor unit of the bushing actuator (in the y direction - again entering / leaving the page - with each straight conductor segment arbitrarily shown in the x direction in this figure). Note that one or more cooling channels can take any path and need not be a straight path along the length of the coil winding. For example, the channel path can be optimized to ensure that each winding in the coil is superimposed with the cooling water at some point. Shown is the cooling surface 803 (the interface between the surface-wound electric coil 602 and the cooling plate 610) (indicated by the larger arrow). Heat is transferred 820 from the coil 602 to the cooling plate 610 at these locations. Due to the configuration of the system 600 ( Figure 6 ), an additional cooling surface 804 facing the inner windings of the surface-wound electric coil 602 towards the armature 604 is available. The inner windings of the surface-wound electric coil 602 are in contact with the armature 604, which can form an additional cooling surface. Heat is transferred 820 from the surface-wound electric coil 602 to the armature 604 across the coil (or copper) height H at these locations (for the outermost windings of the surface-wound electric coil 602, the thermal resistance of the armature can be > 10 times higher than that of the windings adjacent to the cooling plate 610). The armature 604 can include additional optional cooling channels 850 (two are arbitrarily shown here) to transfer the heat transferred from the inner coil surface to the armature 604.

[0081] Figure 9 Illustrated is how multiple surface-wound electric coils 602 and multiple cooling plates 610 are configured to be assembled 900 piece by piece, where the alternating surface-wound electric coils 602 and cooling plates 610 are coupled to each other to form the cooling system 600. The surface-wound electric coil 602 and plate 610 laminations 902 are configured to be mechanically pre-loaded in the moving direction of the linear actuator. Figure 9 Depicted is an example assembly scheme that includes laminating the cooling plate 610 and the surface-wound electric coil 602 onto a common armature 604 and coherently welding (and testing) the connections. The entire assembly can be compressed and held by, for example, tie rods and / or other methods. Due to controlled compression and / or other factors, it is possible to maintain good thermal contact between the electrical insulation on the cooling plate 610 and the surface-wound electric coil 602 while omitting the potting layer. This also makes it easier to disassemble and reuse all the working parts of the press for repair / refurbishment.

[0082] As Figure 9As shown, the cooling plate 610 only needs to be as wide as the single surface-wound electric coil 602 and long enough to span the surface-wound electric coil 602 plus the coverage area for cooling and electrical bus connections and interfacing. This results in a separate cooling plate 610 that is smaller than those typically used in prior systems. Additionally, as described above ( Figure 8 ), the thickness of the cooling plate 610 no longer limits the magnetic gap (compared to prior systems), which means the cooling plate 610 can be thicker than those typically used in prior systems (e.g., a thickness of about 0.9 mm). This facilitates cheaper and easier manufacturing, among other advantages.

[0083] Figure 10 Regions 1000, 1002 of the illustrated surface-wound electric coil 602 / plate 610 are configured for routing electrical connections through the volume between the cooling plates 610 and penetrating the cooling plates 610 (e.g., in the (xz) cross-section in this example, in the y-direction in this example). The inner leads 650 (in region 1000) can be soldered to the adjacent surface-wound electric coil 602 that is routed through the groove 652 or other orifice in the armature 604. The outer leads 654 can be connected to another surface-wound electric coil 602 in series, the junction between parallel phases, or to an amplifier through a bus connection formed in the (three-dimensional) region 1002 beyond the ends of the surface-wound electric coil 602. This arrangement allows for a relatively simple implementation of distributed phase current. Note: One of the main benefits of using distributed phase current is to reduce the spatial harmonics in the generated electromotive force of the actuator and thus more effectively utilize the available magnetic flux from the opposite side (rotor or stator, e.g., Halbach tracks) to generate thrust. The result should be a higher force density actuator with lower force ripple.

[0084] Figure 11 An example three-phase actuator 1100 with a distributed current distribution 1102 is illustrated. The inner leads 650, outer leads 654, and / or the multiple surface-wound electric coils 602 are configured such that distributed phase current is achieved through stacked windings 1104, 1106. For example, half-coil pairing can be used between the cooling plates 610. As Figure 11 shown, achieving distributed phase current typically requires stacking with wiring, which requires additional volume and solutions to difficult 3D wiring problems. The advantage of the cooling system 600 ( Figure 6 ), is that by simply allowing individual phases to be connected to a bus that penetrates the motor volume along the drive direction (y-axis) of the motor, distributed phase current can be achieved using flat wire coils without having to stack the coils in the magnetic gap. Additionally, the additional cooling plates 610 and / or the number of windings per phase can be selected as part of the inherent design freedoms included in the system 600.Figure 11 FIG. illustrates an example five-phase actuator 1110 and an actuator package 1112 having a certain number of actuators 1110 connected in series. An actuator is a single group of phases that make up a complete electrical cycle (e.g., for a three-phase actuator, a group of the individual R, S, and T phases). The actuator package or component can be multiple three-phase actuators that are electrically connected (all R phases in parallel with each other, and similarly for S and T), or just a number of actuators that are mechanically packaged into one assembly.

[0085] Figure 12 FIG. illustrates an example three-phase forcer with centralized 1200 and distributed 1202 current distributions. The inner leads 650, outer leads 654, and / or the multiple surface-wound electrical coils 602 are configured such that the centralized 1200 phase current is achieved using stacked single coils 602 between the cooling plates 610. Figure 12 FIG. illustrates a half-coil pairing 1204 where each phase 1206 has five cooling plates 610, but any number of half-coil pairs and cooling plates 610 per phase is possible. This maintains the design freedom to adjust the number of turns per phase and the number of cooling surfaces per phase such that optimal performance can be achieved, and / or there are other advantages.

[0086] Figure 13 FIG. illustrates a cooling method for a linear actuator. The linear actuator can be a Lorentz actuator or a core linear actuator with magnetic material present in the armature (with or without slots or magnetic teeth, as described above, e.g., these can also be referred to as slotted-core LPMSM (linear permanent magnet synchronous motors)). The method 1300 can be performed using, for example, the cooling system described herein. The cooling system and the linear actuator can form part of a lithography apparatus or metrology apparatus configured for a semiconductor manufacturing process, and / or part of other systems.

[0087] The operations of the method 1300 presented below are intended to be illustrative. In some embodiments, the method 1300 can be implemented without one or more of the additional operations described and / or without one or more of the operations discussed. Additionally, Figure 13 the order of the operations of the method 1300 illustrated and described below is not intended to be restrictive.

[0088] At operation 1302, a plurality of wound electrical coils are formed. The coils are configured to be energized to provide an electromagnetic force for the linear actuator. The plurality of wound electrical coils are configured to surround the armature of the linear actuator. The plurality of wound electrical coils can include, for example, surface-wound flat wire coils or toroidally-wound coils. The plurality of wound electrical coils can be welded to each other via internal leads routed through grooves in the armature. The plurality of wound electrical coils include external leads configured to be coupled to another coil in series, to a junction between parallel phases, or to an amplifier. The internal leads, the external leads, and / or the plurality of wound electrical coils are configured such that distributed phase current is achieved through stacked windings. In some embodiments, the internal leads, the external leads, and / or the plurality of wound electrical coils are configured such that concentrated phase current is achieved using stacked coils between cooling plates. In some embodiments, operation 1302 is performed by a plurality of wound electrical coils and / or other components that are the same as or similar to the plurality of wound electrical coils described above.

[0089] At operation 1304, a plurality of cooling plates are formed and positioned in thermal contact with the plurality of wound electrical coils. The plurality of cooling plates are configured to cool the plurality of wound electrical coils. Individual ones of the plurality of cooling plates are configured to surround the armature and are positioned between adjacent individual coils such that the plurality of wound electrical coils and the plurality of cooling plates form a series of alternating plates and coils along the length of the armature. The length includes a portion or the full length of the armature. In some embodiments, the plurality of cooling plates have a generally rectangular cross-section having one or more cooling channels formed therein, the one or more cooling channels being configured to carry a coolant formed therein. In some embodiments, operation 1304 is performed by a plurality of cooling plates and / or other components that are the same as or similar to the plurality of cooling plates described above.

[0090] At operation 1306, the plurality of wound electrical coils and the plurality of cooling plates are oriented in a plane generally perpendicular to the length of the armature. At operation 1308, the plurality of wound electrical coils and the plurality of cooling plates are assembled piece by piece, wherein alternating wound electrical coils and cooling plates are coupled to each other to form the cooling system. At operation 1310, the plurality of cooling plates are coupled together such that one or more cooling channels carry the coolant to cool the plurality of wound electrical coils along the length of the armature. In some embodiments, operations 1306 through 1310 are performed by a plurality of wound electrical coils and / or a plurality of cooling plates and / or other components that are similar and / or the same as the coils and / or cooling plates described above.

[0091] In some embodiments, compared to the parallel orientation and / or integral structure of multiple wound electrical coils and multiple cooling plates, the generally vertical orientation of the multiple wound electrical coils and multiple cooling plates relative to the length of the armature and / or the piece-by-piece separation nature of the multiple wound electrical coils and multiple cooling plates are configured to reduce the shear force along the length of the armature on mechanical fasteners and / or adhesives that connect any two wound electrical coils and / or cooling plates. In some embodiments, the coil and plate stack is configured to be mechanically preloaded in the direction of movement of the linear actuator to reduce and / or eliminate the need for gluing and / or potting between the coils and the coil housing (which may optionally be included in the Figure 6 system shown) to couple the coils to the cooling plates ( Figure 7 showing the reaction force 710).

[0092] In some embodiments, compared to the parallel orientation of the cooling plates, the generally vertical orientation of the multiple cooling plates relative to the length of the armature is configured to reduce the distance between the magnets and the ferromagnetic back iron of the linear actuator. In some embodiments, the multiple cooling plates include regions having one or more cooling channels and / or electrical wiring in a plane, regions for bus wiring in a normal direction, and / or regions for mechanical coupling to the armature, another plate, and / or a coil.

[0093] At operation 1312, an insulator and / or adhesive can be positioned between the multiple wound electrical coils and the multiple cooling plates. The insulator can include Kapton, ceramic sheets, nylon sheets, Teflon sheets, and / or any other anti-corona polyimide. Generally, any material that can be used as an electrical insulator between a coil winding and a metal (as an example material) cooling plate can include the insulator. In some embodiments, the cooling plate itself can be an insulating ceramic material, and there can be some material between the cooling plate and the coil winding configured for thermal coupling. Operation 1312 can also include providing a cladding surface configured to enclose the multiple wound electrical coils, the multiple cooling plates, and the armature. In some embodiments, operation 1312 is performed by the insulator, adhesive, and / or cladding surface and / or other components described herein.

[0094] Various embodiments of the system and method are disclosed in the following numbered aspects:

[0095] 1. A cooling system for a linear actuator, the system comprising: a plurality of wound electrical coils configured to be energized to provide an electromagnetic force for the linear actuator, the plurality of wound electrical coils being configured to surround an armature of the linear actuator; and a plurality of cooling plates in thermal contact with the plurality of wound electrical coils and configured to cool the plurality of wound electrical coils, wherein individual ones of the plurality of cooling plates are configured to surround the armature and be positioned between adjacent individual coils such that the plurality of wound electrical coils and the plurality of cooling plates form a series of alternating plates and coils along the length of the armature.

[0096] 2. The system according to aspect 1, wherein the plurality of wound electrical coils and the plurality of cooling plates are configured to be oriented in a plane substantially perpendicular to the length of the armature.

[0097] 3. The system according to any of the preceding aspects, wherein the plurality of wound electrical coils and the plurality of cooling plates are configured to be assembled piece by piece, with alternating wound electrical coils and cooling plates being coupled to each other to form the cooling system.

[0098] 4. The system according to any of the preceding aspects, wherein, compared to a parallel orientation and / or an integral structure of the plurality of wound electrical coils and the plurality of cooling plates, a substantially vertical orientation of the plurality of wound electrical coils and the plurality of cooling plates with respect to the length of the armature, and / or a piece-by-piece separated nature of the plurality of wound electrical coils and the plurality of cooling plates, is configured to reduce shear forces along the length of the armature on mechanical fasteners and / or adhesives that connect any two wound electrical coils and / or cooling plates.

[0099] 5. The system according to any of the preceding aspects, wherein, compared to a parallel orientation of the cooling plates, a substantially vertical orientation of the plurality of cooling plates with respect to the length of the armature is configured to reduce the distance between a magnet of the linear actuator and a ferromagnetic back iron.

[0100] 6. The system according to any of the preceding aspects, wherein the plurality of cooling plates have a substantially rectangular cross-section having one or more cooling channels formed therein, the one or more cooling channels being configured to carry a coolant.

[0101] 7. The system according to any of the preceding aspects, wherein the plurality of cooling plates are configured to be coupled together such that the one or more cooling channels carry the coolant to cool the plurality of wound electrical coils along the length of the armature.

[0102] 8. The system according to any one of the foregoing aspects, wherein the plurality of cooling plates include areas having one or more cooling channels and / or electrical wiring in a plane, areas for bus wiring in a normal direction, and / or areas for mechanically coupling to the armature, another plate, and / or the coil.

[0103] 9. The system according to any one of the foregoing aspects, wherein the plurality of wound electrical coils are configured to be welded to each other via inner leads routed through grooves in the armature.

[0104] 10. The system according to any one of the foregoing aspects, wherein the plurality of wound electrical coils include outer leads configured to couple to another coil in series, to a junction between parallel phases, or to an amplifier.

[0105] 11. The system according to any one of the foregoing aspects, wherein the inner leads, the outer leads, and / or the plurality of wound electrical coils are configured such that distributed phase currents are achieved by stacked windings.

[0106] 12. The system according to any one of the foregoing aspects, wherein the inner leads, the outer leads, and / or the plurality of wound electrical coils are configured such that concentrated phase currents are achieved using stacked coils between the cooling plates.

[0107] 13. The system according to any one of the foregoing aspects, further comprising an insulator and / or an adhesive positioned between the plurality of wound electrical coils and the plurality of cooling plates.

[0108] 14. The system according to any one of the foregoing aspects, wherein the insulator includes Kapton, a ceramic sheet, a nylon sheet, a Teflon sheet, or another anti-corona polyimide.

[0109] 15. The system according to any one of the foregoing aspects, wherein the plurality of wound electrical coils include surface-wound flat wire coils or toroidally-wound coils.

[0110] 16. The system according to any one of the foregoing aspects, wherein the coil and plate stack is configured to be mechanically pre-loaded in the direction of movement of the linear actuator to eliminate the need for an adhesive and / or potting material between the coil and the coil housing for coupling the coil to the cooling plate during operation.

[0111] 17. The system according to any one of the foregoing aspects, further comprising a cladding surface configured to enclose the plurality of wound electrical coils, the plurality of cooling plates, and the armature.

[0112] 18. The system according to any one of the foregoing aspects, wherein the linear actuator is a Lorentz actuator or a linear actuator having a magnetic material in its armature, with or without slots or magnetic teeth in the armature.

[0113] 19. The system according to any one of the foregoing aspects, wherein the length includes a part or the entire length of the armature.

[0114] 20. The system according to any one of the foregoing aspects, wherein the cooling system and the linear actuator form part of a lithography apparatus or a metrology apparatus configured for a semiconductor manufacturing process.

[0115] 21. A method for cooling a linear actuator, the method comprising: forming a plurality of wound electrical coils configured to be energized to provide an electromagnetic force for the linear actuator, the plurality of wound electrical coils being configured to surround the armature of the linear actuator; and forming a plurality of cooling plates and positioning the plurality of cooling plates in thermal contact with the plurality of wound electrical coils, the plurality of cooling plates being configured to cool the plurality of wound electrical coils, wherein individual ones of the plurality of cooling plates are configured to surround the armature and are positioned between adjacent individual coils such that the plurality of wound electrical coils and the plurality of cooling plates form a series of alternating plates and coils along the length of the armature.

[0116] 22. The method according to aspect 21, further comprising orienting the plurality of wound electrical coils and the plurality of cooling plates in a plane substantially perpendicular to the length of the armature.

[0117] 23. The method according to any one of the foregoing aspects, further comprising assembling the plurality of wound electrical coils and the plurality of cooling plates piece by piece, wherein the alternating wound electrical coils and cooling plates are coupled to each other to form the cooling system.

[0118] 24. The method according to any one of the foregoing aspects, wherein, compared to a parallel orientation and / or an integral structure of the plurality of wound electrical coils and the plurality of cooling plates, a substantially vertical orientation of the plurality of wound electrical coils and the plurality of cooling plates with respect to the length of the armature, and / or a piece-by-piece separated nature of the plurality of wound electrical coils and the plurality of cooling plates is configured to reduce shear forces along the length of the armature on mechanical fasteners and / or adhesives connecting any two wound electrical coils and / or cooling plates.

[0119] 25. The method according to any one of the foregoing aspects, wherein, compared to a parallel orientation of the cooling plates, a substantially vertical orientation of the plurality of cooling plates with respect to the length of the armature is configured to reduce the distance between the magnet of the linear actuator and the ferromagnetic back iron.

[0120] 26. The method according to any one of the foregoing aspects, wherein the plurality of cooling plates have a substantially rectangular cross-section having one or more cooling channels formed therein, the one or more cooling channels being configured to carry a coolant.

[0121] 27. The method according to any one of the foregoing aspects, further comprising coupling the plurality of cooling plates together such that the one or more cooling channels carry the coolant to cool the plurality of wound electrical coils along the length of the armature.

[0122] 28. The method according to any one of the foregoing aspects, wherein the plurality of cooling plates include regions having one or more cooling channels and / or electrical wiring in a plane, regions for bus wiring in a normal direction, and / or regions for mechanical coupling to the armature, another plate, and / or the coils.

[0123] 29. The method according to any one of the foregoing aspects, further comprising welding the plurality of wound electrical coils to each other via inner leads routed through grooves in the armature.

[0124] 30. The method according to any one of aspects 21 to 29, wherein the plurality of wound electrical coils include outer leads configured to be coupled to another coil in series, to a junction between parallel phases, or to an amplifier.

[0125] 31. The method according to any one of the foregoing aspects, wherein the inner leads, the outer leads, and / or the plurality of wound electrical coils are configured such that distributed phase currents are achieved by stacked windings.

[0126] 32. The method according to any one of the foregoing aspects, wherein the inner leads, the outer leads, and / or the plurality of wound electrical coils are configured such that concentrated phase currents are achieved using stacked coils between the cooling plates.

[0127] 33. The method according to any one of the foregoing aspects, further comprising positioning an insulator and / or an adhesive between the plurality of wound electrical coils and the plurality of cooling plates.

[0128] 34. The method according to any one of the foregoing aspects, wherein the insulator includes Kapton, a ceramic sheet, a nylon sheet, a Teflon sheet, or another anti-corona polyimide.

[0129] 35. The method according to any one of the foregoing aspects, wherein the plurality of wound electrical coils include surface-wound flat wire coils or toroidally-wound coils.

[0130] 36. The method according to any one of the foregoing aspects, wherein the coil and the plate stack are configured to be mechanically preloaded in the moving direction of the linear actuator to eliminate the need for an adhesive and / or potting material between the coil and the coil housing for coupling the coil to the cooling plate during operation.

[0131] 37. The method according to any one of the foregoing aspects, further comprising providing a cladding surface configured to enclose the plurality of wound electrical coils, the plurality of cooling plates, and the armature.

[0132] 38. The method according to any one of the foregoing aspects, wherein the linear actuator is a Lorentz actuator or a linear actuator having magnetic material in its armature, with or without slots or magnetic teeth in the armature.

[0133] 39. The method according to any one of the foregoing aspects, wherein the length includes a part or the entire length of the armature.

[0134] 40. The method according to any one of the foregoing aspects, wherein the cooling system and the linear actuator form part of a lithography apparatus or a metrology apparatus configured for a semiconductor manufacturing process.

[0135] 41. A lithography apparatus configured for a semiconductor manufacturing process, comprising: a linear actuator; and a cooling system for the linear actuator, the cooling system including: a plurality of wound electrical coils configured to be energized to provide an electromagnetic force for the linear actuator, the plurality of wound electrical coils being configured to surround an armature of the linear actuator; and a plurality of cooling plates in thermal contact with the plurality of wound electrical coils and configured to cool the plurality of wound electrical coils, wherein individual ones of the plurality of cooling plates are configured to surround the armature and are positioned between adjacent individual coils such that the plurality of wound electrical coils and the plurality of cooling plates form a series of alternating plates and coils along the length of the armature.

[0136] Although the concepts disclosed herein can be used with linear actuators associated with fabricating wafers on substrates such as silicon wafers, it should be understood that the disclosed concepts can be used with any type of manufacturing system that may include a linear actuator, e.g., a linear actuator for fabricating on substrates other than silicon wafers. Additionally, combinations and sub - combinations of the disclosed elements can include different embodiments. For example, the cooling system and the associated lithography apparatus including the cooling system can include different embodiments, and / or these features can be used together in the same embodiment.

[0137] The foregoing description is intended to be illustrative and not restrictive. Accordingly, those skilled in the art will appreciate that modifications can be made as described without departing from the scope of the claims set forth below.

Claims

1. A cooling system for a linear actuator, the system comprising: a plurality of wound electrical coils configured to be energized to provide an electromagnetic force for the linear actuator, the plurality of wound electrical coils being configured to surround an armature of the linear actuator; and a plurality of cooling plates in thermal contact with the plurality of wound electrical coils and configured to cool the plurality of wound electrical coils, wherein individual ones of the plurality of cooling plates are configured to surround the armature and be positioned between adjacent individual coils such that the plurality of wound electrical coils and the plurality of cooling plates form a series of alternating plates and coils along the length of the armature.

2. The system according to claim 1, wherein, The plurality of wound electrical coils and the plurality of cooling plates are configured to be oriented in a plane substantially perpendicular to the length of the armature.

3. The system according to claim 1, wherein, The plurality of wound electrical coils and the plurality of cooling plates are configured to be assembled piece by piece, wherein the alternating wound electrical coils and cooling plates are coupled to each other to form the cooling system.

4. The system according to claim 1, wherein, Compared to a parallel orientation and / or an integral structure of the plurality of wound electrical coils and the plurality of cooling plates, the substantially vertical orientation of the plurality of wound electrical coils and the plurality of cooling plates relative to the length of the armature, and / or the piece-by-piece separation nature of the plurality of wound electrical coils and the plurality of cooling plates are configured to reduce shear forces along the length of the armature on mechanical fasteners and / or adhesives that connect any two wound electrical coils and / or cooling plates.

5. The system according to claim 1, wherein Compared to a parallel orientation of the cooling plates, the substantially vertical orientation of the plurality of cooling plates relative to the length of the armature is configured to reduce the distance between the magnets and the ferromagnetic back iron of the linear actuator.

6. The system according to claim 1, wherein, The plurality of cooling plates have a substantially rectangular cross-section having one or more cooling channels formed therein, the one or more cooling channels being configured to carry a coolant; and wherein the plurality of cooling plates are configured to be coupled together such that the one or more cooling channels carry the coolant to cool the plurality of wound electrical coils along the length of the armature.

7. The system according to claim 1, wherein, The plurality of cooling plates include regions having one or more cooling channels and / or electrical wiring in a plane, regions for bus wiring in a normal direction, and / or regions for mechanical coupling to the armature, another plate, and / or a coil.

8. The system according to claim 1, wherein The plurality of wound electrical coils are configured to be welded to each other via inner leads routed through grooves in the armature; and the inner leads, outer leads, and / or the plurality of wound electrical coils are configured such that distributed phase currents are achieved by stacked windings; and the inner leads, the outer leads, and / or the plurality of wound electrical coils are configured such that concentrated phase currents are achieved using stacked coils between the cooling plates.

9. The system according to claim 1, wherein: the plurality of wound electrical coils include outer leads configured to be coupled to another coil in series, to a junction between parallel phases, or to an amplifier; the inner leads, the outer leads, and / or the plurality of wound electrical coils are configured such that distributed phase currents are achieved by stacked windings; and The inner lead, the outer lead, and / or the plurality of wound electrical coils are configured such that concentrated phase current is achieved using stacked coils between the cooling plates.

10. The system according to claim 1, further comprising insulation and / or adhesive positioned between the plurality of wound electrical coils and the plurality of cooling plates, wherein, The insulation includes Kapton, ceramic sheet, nylon sheet, Teflon sheet, or another anti-corona polyimide.

11. The system according to claim 1, wherein, The plurality of wound electrical coils includes surface-wound flat wire coils or toroidally-wound coils; and The coil and plate stack is configured to be mechanically pre-loaded in the direction of movement of the linear actuator to eliminate the need for an adhesive and / or potting material between the coil and the coil housing for coupling the coil to the cooling plate during operation.

12. The system of claim 1, further comprising a cladding surface configured to enclose the plurality of wound electrical coils, the plurality of cooling plates, and the armature.

13. The system according to claim 1, wherein The linear actuator is a Lorentz actuator or a linear actuator having magnetic material in its armature, with or without slots or magnetic teeth in the armature; The length includes a portion or the full length of the armature; and The cooling system and the linear actuator form part of a lithography apparatus or metrology apparatus configured for a semiconductor manufacturing process.

14. A method for cooling a linear actuator, the method comprising: forming a plurality of wound electrical coils configured to be energized to provide electromagnetic force for the linear actuator, the plurality of wound electrical coils configured to surround an armature of the linear actuator; and and forming a plurality of cooling plates and positioning the plurality of cooling plates in thermal contact with the plurality of wound electrical coils, the plurality of cooling plates configured to cool the plurality of wound electrical coils, wherein individual ones of the plurality of cooling plates are configured to surround the armature and are positioned between adjacent individual coils such that the plurality of wound electrical coils and the plurality of cooling plates form a series of alternating plates and coils along the length of the armature.

15. A lithography apparatus configured for a semiconductor manufacturing process, comprising: a linear actuator; and a cooling system for the linear actuator, the cooling system comprising: a plurality of wound electrical coils configured to be energized to provide electromagnetic force for the linear actuator, the plurality of wound electrical coils configured to surround an armature of the linear actuator; and a plurality of cooling plates in thermal contact with the plurality of wound electrical coils and configured to cool the plurality of wound electrical coils, wherein individual ones of the plurality of cooling plates are configured to surround the armature and are positioned between adjacent individual coils such that the plurality of wound electrical coils and the plurality of cooling plates form a series of alternating plates and coils along the length of the armature.

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