Cooling System for Linear Actuators

Abstract

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

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Application No. 63 / 422,717, filed November 4, 2022, which is incorporated herein by reference in its entirety. [Background technology]

[0002]

[0002] This description relates generally to cooling systems for linear actuators.

[0003] Linear actuators are well known. Multi-phase electromagnetic linear actuators are used, for example, as long-stroke actuators in lithography apparatus, metrology systems, and other devices. Lithographic (e.g., projection) apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such cases, a patterning device (e.g., a mask) may contain or provide a pattern (a “design layout”) corresponding to an individual layer of the IC; this pattern can be transferred onto a target portion (e.g., comprising one or more dies) on a substrate (e.g., a silicon wafer) that is coated with a layer of radiation-sensitive material (a “resist”), such as by irradiating the target portion through the pattern on the patterning device. Typically, a single substrate will contain several adjacent target portions (one target portion at a time) onto which the pattern is successively transferred by the lithographic projection apparatus. In one type of lithographic projection apparatus, the pattern on the entire patterning device is transferred onto one target portion in a single pass. Such an apparatus is commonly referred to as a stepper. In an alternative apparatus, commonly referred to as a step-and-scan apparatus, the projection beam scans the patterning device in a given reference direction (the "scan" direction), and the substrate moves parallel or anti-parallel to this reference direction. Different parts of the pattern on the patterning device are gradually transferred onto one target portion. The various movements of the lithographic apparatus can be facilitated by one or more linear actuators. Summary of the Invention

[0004]

[0004] A cooling system for a linear actuator is described. The cooling system includes a wound electric coil and a cooling plate. The electric coil is configured to be energized to provide electromagnetic force for the linear actuator. The electric coil is configured to surround an armature of the linear actuator. The cooling plate is in thermal contact with the electric coil and configured to cool the electric coil. Each cooling plate is configured to surround the armature and is positioned between adjacent individual coils such that the electric coils and cooling plates form an alternating arrangement of plates and coils along the length of the armature. Another advantage is that the electric coils and cooling plates are configured to be assembled in parts, and alternating wound electric coils and cooling plates are coupled to each other to form the cooling system. The generally perpendicular orientation of the electric coil and cooling plate to the length of the armature and / or the assembled nature of the electric coil and cooling plate in separate components are configured to reduce shear forces on the mechanical fasteners and / or adhesives joining any two turns of the electric coil and / or cooling plate along the length of the armature, compared to a parallel orientation and / or unitary structure of multiple electric coils and multiple cooling plates. Additionally, for implementations with a non-slotted ferromagnetic armature serving as the back iron, the generally perpendicular orientation of the cooling plate to the length of the armature is configured to reduce the distance between the magnets of the linear actuator and the ferromagnetic back iron, compared to a parallel orientation of the cooling plate. Also, the orientation of the electric coil and cooling plate 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 possible.

[0005]

[0005] According to one embodiment, a system for a linear actuator is provided. The system includes a plurality of wound electric coils configured to be energized to provide electromagnetic force for the linear actuator. The plurality of wound electric 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 electric coils and configured to cool the plurality of wound electric coils. Each plate of the plurality of cooling plates is configured to surround the armature, and is positioned between adjacent individual coils such that the plurality of wound electric coils and the plurality of cooling plates form an alternating arrangement of plates and coils along the length of the armature.

[0006]

[0006] In some embodiments, the multiple wound electrical coils and multiple cooling plates are configured to be oriented in a plane generally perpendicular to the length of the armature.

[0007]

[0007] In some embodiments, the multiple wound electrical coils and multiple cooling plates are configured to be assembled piece by piece, with alternating wound electrical coils and cooling plates coupled to one another to form a cooling system.

[0008]

[0008] In some embodiments, the generally perpendicular orientation of the multiple wound electrical coils and multiple cooling plates relative to the length of the armature, and / or the assembled nature of the multiple wound electrical coils and multiple cooling plates in individual components, is configured to reduce shear forces on the mechanical fasteners and / or adhesives joining any two wound electrical coils and / or cooling plates along the length of the armature, compared to a parallel orientation and / or unitary structure of the multiple wound electrical coils and multiple cooling plates.

[0009]

[0009] In some embodiments, the generally perpendicular orientation of the multiple cooling plates to the length of the armature is configured to reduce the distance between the magnets and the ferromagnetic back iron of the linear actuator compared to a parallel orientation of the multiple cooling plates.

[0010] In some embodiments, the plurality of cooling plates have a generally rectangular cross-section with one or more cooling channels formed therein configured to carry a coolant.

[0011]

[0011] In some embodiments, multiple cooling plates are configured to be coupled together such that one or more cooling channels carry coolant to cool multiple wound electrical coils along the length of the armature.

[0012]

[0012] In some embodiments, the multiple cooling plates include areas with one or more cooling channels and / or in-plane electrical wiring, areas for normal bus wiring, and / or areas for mechanical coupling to an armature, another plate and / or coil.

[0013]

[0013] In some embodiments, the multiple wound electrical coils are configured to be soldered to each other via inner lead wires routed through grooves in the armature, the location of which may be selected, for example, to minimize air gaps in the magnetic flux path through the armature.

[0014]

[0014] In some embodiments, the multiple-wound electrical coil includes an outer lead configured to couple in series with another coil, to couple to a junction between parallel phases, or to couple to an amplifier.

[0015] In some embodiments, the inner lead, the outer lead and / or the multiple turn electrical coil are configured such that the overlapping windings provide distributed phase current.

[0016] In some embodiments, the inner lead, outer lead and / or multiple turn electrical coil are configured to achieve concentrated phase current using coils stacked between cooling plates.

[0017] In one embodiment, the system further includes an insulating material and / or adhesive positioned between the plurality of wound electrical coils and the plurality of cooling plates.

[0018] In some embodiments, the insulating material includes Kapton, ceramic sheet, nylon sheet, Teflon sheet, or another corona-resistant polyimide. Generally, any material that can function as an electrical insulator between the coil windings and a metal (as an example of a material) cooling plate can include the insulating material. In some embodiments, the cooling plate itself can be an insulating ceramic material, or there can be some material configured for thermal coupling between the cooling plate and the coil windings.

[0019] In some embodiments, the coil and / or cooling plate material may be selected for optimal matching of thermal expansion coefficients between the coil and cooling plate layers along the length of the armature.

[0020]

[0020] In some embodiments, the multiple wound electrical coil comprises a surface wound flat wire coil or a toroidal wound coil.

[0021]

[0021] In some embodiments, the coil and plate stack is configured to be mechanically pre-stressed in the direction of movement of the linear actuator to eliminate the need for glue and / or potting between the coil and coil housing to bond the coil to the cooling plate during operation, to maintain good thermal contact, and / or for other reasons.

[0022]

[0022] In some embodiments, the system includes a plurality of wound electrical coils, a plurality of cooling plates, and a canning surface configured to surround the armature.

[0023]

[0023] In some embodiments, the linear actuator is a Lorentz actuator or a linear actuator in which there is magnetic material within its armature, with or without slots or magnetic teeth in the armature.

[0024]

[0024] In some embodiments, the length includes a portion or the entire length of the armature.

[0025]

[0025] In some embodiments, the cooling system and linear actuator form part of a lithography or metrology apparatus configured for a semiconductor manufacturing process, or any other apparatus requiring precise movement under high accelerations.

[0026]

[0026] 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 electromagnetic force for the linear actuator, the plurality of wound electrical coils configured to surround an armature of the linear actuator. The method includes forming a plurality of cooling plates and positioning them in thermal contact with the plurality of wound electrical coils, the plurality of cooling plates configured to cool the plurality of wound electrical coils, individual plates of the plurality of cooling plates configured to surround the armature, and positioned between adjacent individual coils such that the plurality of wound electrical coils and the plurality of cooling plates form an alternating arrangement of plates and coils along a length of the armature.

[0027]

[0027] According to another embodiment, there is provided a lithographic apparatus configured for use in a semiconductor manufacturing process. The lithographic apparatus includes a linear actuator and a cooling system for the linear actuator. The cooling system includes a plurality of wound electric coils configured to be energized to provide electromagnetic force for the linear actuator. The plurality of wound electric coils are configured to surround an armature of the linear actuator. A plurality of cooling plates in thermal contact with the plurality of wound electric coils are configured to cool the plurality of wound electric 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 electric coils and the plurality of cooling plates form an alternating arrangement of plates and coils along the length of the armature. [Brief explanation of the drawings]

[0028]

[0028] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate one or more embodiments and, together with the following description, explain those 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 symbols indicate corresponding parts, and in which: [Figure 1]

[0029] 1 illustrates a lithographic apparatus that may include a linear actuator with the present cooling system, according to one embodiment; [Figure 2]

[0030] 1 illustrates an embodiment of a lithographic cell or cluster that may include a linear actuator with the present cooling system in one or more devices of the lithographic cell or cluster, according to one embodiment. [Figure 3]

[0031] 1 illustrates an armature with a surface wound electrical coil compared to an armature with a racetrack wound coil, according to one embodiment. [Figure 4]

[0032] 1 illustrates a phase current distribution configuration for a linear actuator, according to one embodiment. [Figure 5]

[0033] 1 illustrates an exemplary three-phase current distribution configuration with linear actuator magnet tracks, according to one embodiment. [Figure 6]

[0034] 1 illustrates a cooling system for a linear actuator, according to one embodiment. [Figure 7]

[0035] 1 illustrates an embodiment in which the coil and plate stack is configured to be mechanically pre-loaded in the direction of linear actuator movement to eliminate the need for glue and / or potting between the coil and coil housing to bond the coil to the cooling plate during operation, and a generally perpendicular orientation of the multiple cooling plates to the armature length is configured to reduce the distance between the magnets and ferromagnetic back irons of the linear actuator compared to a parallel orientation of the cooling plates. [Figure 8]

[0036] 1 illustrates cooling channels in a cooling plate connected to main inlet / outlet channels that traverse the length of the armature and / or motor unit of a linear actuator, according to one embodiment. Note that the cooling channels can follow any path and are not necessarily linear paths along the length of the coil windings. The channel paths can be optimized, for example, to ensure that all windings in the coil are overlapped with cooling water at some point. [Figure 9]

[0037] 1 illustrates one embodiment of a configuration in which multiple surface-wound electrical coils and multiple cooling plates are assembled into a component, with alternating surface-wound electrical coils and cooling plates coupled together to form a cooling system. [Figure 10]

[0038] 10 illustrates an area of ​​a coil / plate configured to route electrical connections through the volume between cooling plates and penetrate the cross section of the cooling plates, according to one embodiment. [Figure 11]

[0039] 1 illustrates an exemplary three-phase forcer with distributed current distribution, according to one embodiment. [Figure 12]

[0040] 1 illustrates an exemplary three-phase forcer with concentrated and distributed current distribution, according to one embodiment. [Figure 13]

[0041] 1 illustrates a cooling method for a linear actuator, according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0029]

[0042] Two distinct types of multi-phase electromagnetic linear actuators are used as long-stroke actuators in lithography apparatus, metrology systems, and other devices. For example, in lithography apparatus, Lorentz actuators, linear actuators with magnetic material in their armatures, with or without slots or magnetic teeth in the armatures, and / or other motion systems are used (these may also be known as slotted iron-core LPMSMs (linear permanent magnet synchronous motors)). Higher accelerations of lithography apparatus stages are desired. Higher stage accelerations improve the productivity of lithography apparatuses, thereby lowering the cost per die (or per microchip).

[0030]

[0043] However, ever-higher stage accelerations cause increased dynamic and thermal loads on current linear actuators used in lithography systems. These increased dynamic and thermal loads can lead to catastrophic temperature increases in linear actuator coils and / or total actuator motor failure, increased amplifier strain, and, depending on the design, increased saturation of the soft magnetic material present in the linear actuator's magnetic circuit. Increased thermal loads are known to reduce the efficiency of the actuator due to thermal runaway effects (higher temperatures increase resistance, and higher resistance dissipates more power, leading to more heat being generated by coils and their temperature increasing). Catastrophic failure of coil windings is widely recognized to occur when the coil temperature exceeds the wire's insulation rating. These factors limit the force density ([N / kg]) achievable by a linear actuator and, therefore, the maximum achievable acceleration ([N / kg] = [m / s2]) of a lithography system stage. For example, three-phase Lorentz actuators using moving magnets or moving coils are currently used in many lithography systems. Lorentz actuators are often preferred because they produce less vibration and less frequent nonlinear behavior than other linear actuators. However, Lorentz actuators are relatively less efficient than other linear actuators and require more average power from the amplifier.

[0031]

[0044] A novel cooling system for a linear actuator is described below. The novel cooling system includes wound electric coils and cooling plates. The electric coils and cooling plates are configured to surround the armature of the linear actuator, with each cooling plate positioned between adjacent individual coils such that the electric coils and cooling plates form an alternating arrangement of plates and coils along the length of the armature. Advantageously, this design allows the electric coils and cooling plates to be assembled in pieces, with alternating electric coils and cooling plates being coupled together to form the cooling system. The generally perpendicular orientation of the electric coils and cooling plates to the length of the armature and / or the individual piece-assembled nature of the electric coils and cooling plates is configured to reduce shear forces on mechanical fasteners and / or adhesives joining any two wound electric coils and / or cooling plates along the length of the armature, compared to a parallel orientation and / or unitary structure of multiple wound electric coils and multiple cooling plates (e.g., as in the conventional linear actuator described above). Additionally, the generally perpendicular orientation of the cooling plate to the length of the armature is configured to reduce the distance between the magnet and the ferromagnetic back iron of the linear actuator compared to a parallel orientation of the cooling plate. Also, the orientation of the electric coil and cooling plate in a plane perpendicular to the length of the armature is configured to resist undesired movement or deformation of the linear actuator. Therefore, linear actuators with the novel cooling systems described below are more efficient than conventional linear actuators and require reduced average power from amplifiers compared to conventional linear actuators. This allows such linear actuators to achieve higher force densities (limited by coil temperature or amplifier limitations) compared to conventional linear actuators, and therefore higher maximum accelerations of the lithography apparatus stage.

[0032]

[0045] The following introductory paragraph describes the functionality of a general lithography system as one example of many possible use cases for the linear actuators described herein. It should be noted that while specific reference may be made in this document to integrated circuit (IC) manufacturing, it should be understood that the described cooling systems have many other possible applications. For example, the cooling systems may be used in integrated optical systems, guidance and detection patterns for magnetic domain memories, liquid crystal display panels, thin film magnetic heads, etc.

[0033]

[0046] Before transferring the pattern from a patterning device, such as a mask, to the substrate, the substrate may undergo various procedures, such as priming, resist coating, and a soft bake. After exposure, the substrate may undergo other procedures ("post-exposure procedures"), such as a post-exposure bake (PEB), development, a hard bake, and measurement and / or other inspection of the transferred pattern. This series of procedures is used as a basis for creating an individual layer of a device, such as an IC. The substrate may then undergo various processes, such as etching, ion implantation (doping), metallization, oxidation, chemical-mechanical polishing, and the like, all intended to finish off an individual layer of the device. If a device requires several layers, the entire procedure, or a variation thereof, is repeated for each layer. Eventually, a device will be present on each target portion of the substrate. The devices are then separated from each other by techniques such as dicing or sawing, so that the individual devices can be mounted on carriers or connected to pins.

[0034]

[0047] The fabrication of devices, such as semiconductor devices, typically involves processing a substrate (e.g., a semiconductor wafer) using multiple manufacturing processes to form various features and multiple layers of the device. Typically, such layers and features are fabricated and processed using, for example, deposition, lithography, etching, chemical-mechanical polishing, ion implantation, and / or other processes. Multiple devices may be fabricated on multiple dies on a substrate, which may then be separated into individual devices. This device fabrication process can be considered a patterning process. The patterning process includes a patterning step, such as optical and / or nanoimprint lithography, using a patterning device in a lithography apparatus to transfer a pattern on the patterning device to a substrate, and typically, but optionally, includes one or more associated pattern processing steps, such as developing a resist in a developer, baking the substrate using a bake tool, etching with the pattern using an etcher, etc. The patterning process typically includes one or more metrology processes. Lithography apparatus, metrology systems, and other equipment used to fabricate semiconductor devices can use one or more linear actuators with the cooling systems described.

[0035]

[0048] Lithography is a process in the manufacture of devices such as integrated circuits (ICs) in which patterns formed on a substrate define the functional elements of the device, such as microprocessors, memory chips, etc. Similar lithographic techniques are also used in the formation of flat panel displays, microelectromechanical systems (MEMS), and other devices.

[0036]

[0049] 1 schematically illustrates an embodiment of a lithographic apparatus LA, which may include one or more linear actuators and corresponding cooling systems and / or may be associated with the one or more linear actuators and corresponding cooling systems. The apparatus comprises 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., mask table) MT constructed to support a patterning device (e.g., 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., wafer table) WT (e.g., WTa, WTb, or both) configured to hold a substrate (e.g., resist-coated wafer) 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., comprising one or more dies, 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 a transmissive type (e.g. employing a transmissive mask) Alternatively, the apparatus may be of a reflective type (e.g. employing a programmable mirror array of a type as described above, or employing a reflective mask).

[0037]

[0050] The illuminator IL receives a radiation beam from a radiation source SO. The radiation source and the lithographic apparatus may be separate entities, for example when the radiation source is an excimer laser. In such cases, the radiation source is not considered to form part of the lithographic apparatus, and the radiation beam is passed from the source SO to the illuminator IL with the aid of a beam delivery system BD, which may comprise, for example, suitable directing mirrors and / or beam expanders. In other cases, the radiation source may be an integral part of the apparatus, for example when the radiation source is a mercury lamp. The source SO and the illuminator IL, together with the beam delivery system BD if required, may be referred to as a radiation system.

[0038]

[0051] The illuminator IL is capable of modifying the intensity distribution of the beam. The illuminator may be arranged to limit the radial extent of the radiation beam so that the intensity distribution is non-zero within an annular region in a pupil plane of the illuminator IL. Additionally or alternatively, the illuminator IL may be operable to limit the distribution of the beam in the pupil plane so that the intensity distribution is non-zero within a number of equally spaced sectors in the pupil plane. The intensity distribution of the radiation beam in the pupil plane of the illuminator IL may be referred to as an illumination mode.

[0039]

[0052] The illuminator IL may include an adjuster AD configured to adjust the (angular / spatial) intensity distribution of the beam. Typically, at least the outer and / or inner radial extent (commonly referred to as σ-outer and σ-inner, respectively) of the intensity distribution in a pupil plane of the illuminator can be adjusted. The illuminator IL may be operable to change the angular distribution of the beam. For example, the illuminator may be operable to change the number and angular extent of non-zero sectors of the intensity distribution in the pupil plane. By adjusting the intensity distribution of the beam in the pupil plane of the illuminator, different illumination modes can be realized. For example, by limiting the radial and angular extent of the intensity distribution in the pupil plane of the illuminator IL, the intensity distribution may have a multipole distribution, e.g., a dipole, quadrupole, or hexapole distribution. A desired illumination mode can be obtained, for example, by inserting an optical system providing that illumination mode into the illuminator IL or by using a spatial light modulator.

[0040]

[0053] The illuminator IL may be operable to change the polarization of the beam or to adjust the polarization using the adjuster AD. The polarization state of the radiation beam across a pupil plane of the illuminator IL may be referred to as the polarization mode. The use of different polarization modes may enable the realization of higher contrast in the image formed on the substrate W. The radiation beam may be unpolarized. Alternatively, the illuminator may be arranged to linearly polarize the radiation beam. The polarization direction of the radiation beam may vary across the pupil plane of the illuminator IL. The polarization direction of the radiation may be different in different regions of the pupil plane of the illuminator IL. The polarization state of the radiation may be selected depending on the illumination mode. In a multipole illumination mode, the polarization of each pole of the radiation beam may be approximately orthogonal to the position vector of that pole in the pupil plane of the illuminator IL. For example, in a dipole illumination mode, the radiation may be linearly polarized in a direction substantially perpendicular to the bisector of two opposite sectors of the dipole. The radiation beam may be polarized in one of two different orthogonal directions, which may be referred to as the X and Y polarization states. In the case of a quadrupole illumination mode, the radiation in each pole sector may be linearly polarized in a direction substantially perpendicular to the bisector of that sector. This polarization mode may be referred to as XY polarization. Similarly, in the case of a hexapole illumination mode, the radiation in each pole sector may be linearly polarized in a direction substantially perpendicular to the bisector of that sector. This polarization mode may be referred to as TE polarization.

[0041]

[0054] In addition, the illuminator IL generally comprises various other components, such as an integrator IN and a condenser CO. The illumination system may include various types of optical elements, such as refractive, reflective, magnetic, electromagnetic, electrostatic or other types of optical components, or any combination thereof, for directing, shaping or controlling radiation. The illuminator thus provides a conditioned radiation beam B having a desired uniformity and intensity distribution in its cross-section.

[0042]

[0055] 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 whether or not 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 may ensure that the patterning device is at a desired position, for example with respect to the projection system.

[0043]

[0056] The lithographic apparatus may be of a type having two tables (dual stage) or more tables (e.g. two or more substrate tables WTa, WTb, two or more patterning device tables, a substrate table WTa and a substrate-less table WTb below the projection system dedicated to, e.g. supporting, measurement and / or cleaning). Such a "multi-stage" machine may use the additional tables in parallel, or may perform preparatory steps on one or more tables while one or more others are used for exposure. For example, alignment measurements using alignment sensors AS and / or level (height, tilt, etc.) measurements using level sensors LS may be performed.

[0044]

[0057] During operation of the lithographic apparatus, a radiation beam is conditioned and provided by an illumination system IL. The radiation beam B is incident on a patterning device (e.g., mask) MA, which is held on a support structure (e.g., mask table) MT. After passing through the patterning device MA, the radiation beam B passes through a projection system PS, which focuses the beam onto a target portion C of a substrate W. With the aid of a second positioner PW and a position sensor IF (e.g., an interferometer device, a linear encoder, a 2D encoder, or a capacitive sensor), the substrate table WT can be precisely moved, for example, to position different target portions C in the path of the radiation beam B. Similarly, the first positioner PM and another position sensor (not explicitly shown in FIG. 1 ) can be used to precisely position the patterning device MA with respect to the path of the radiation beam B, for example after a mechanical search of a mask library or during a scan. In general, movement of the support structure MT may be realized with the aid of a long-stroke module (coarse positioning) and a short-stroke module (fine positioning), which form part of the first positioner PM. Similarly, movement of the substrate table WT may be realized using a long-stroke module and a short-stroke module, which form part of the second positioner PW. In the case of a stepper (as opposed to a scanner) the support structure MT may be connected to a short-stroke actuator only, or may be fixed. The patterning device MA and the substrate W may be aligned using patterning device alignment marks M1, M2 and substrate alignment marks P1, P2. Although the substrate alignment marks are illustrated as occupying dedicated target portions, they may be located in spaces between the target portions (these are known as scribe-lane alignment marks). Similarly, in situations in which the patterning device MA is provided with more than one die, the patterning device alignment marks may be located between the dies.

[0045]

[0058] The depicted apparatus may be used in at least one of the following modes: 1. In step mode, the support structure MT and the substrate table WT are kept essentially stationary, while a pattern imparted to the radiation beam is projected onto a target portion C at one time (i.e. a single static exposure). The substrate table WT is then shifted in the X and / or Y direction so that a different target portion C can be exposed. In step mode, the maximum size of the exposure field limits the size of the target portion C imaged in a single static exposure. 2. In scan mode, the support structure MT and the substrate table WT are scanned synchronously while a pattern imparted to the radiation beam is projected onto the target portion C (i.e. a single dynamic exposure). The velocity and direction of the substrate table WT relative to the support structure MT may be determined by the (de-)magnification and image reversal characteristics of the projection system PS. In scan mode, the maximum size of the exposure field limits the width of the target portion (non-scan direction) in a single dynamic exposure, whereas the length of the scanning motion determines the height of the target portion (scan direction). 3. In another mode, the support structure MT is kept essentially stationary holding the programmable patterning device, and the substrate table WT is moved or scanned while a pattern imparted to the radiation beam is projected onto a target portion C. In this mode, a pulsed radiation source is typically employed, and the programmable patterning device is updated as required after each movement of the substrate table WT, or in between successive pulses of radiation during a scan. This mode of operation is readily applicable to maskless lithography employing a programmable patterning device such as a programmable mirror array of the type referred to above. Combinations and variations on the above described modes or entirely different modes may also be employed.

[0046]

[0059] The substrate may be processed, before or after exposure, in, for example, a track (a tool that typically applies a layer of resist to a substrate and develops the exposed resist) or a metrology tool or an inspection tool, any or all of which may include a linear actuator with a corresponding cooling system.

[0047]

[0060] Various patterns on or provided by a patterning device may have different process windows, i.e., the space of processing variables within which the patterns are generated. Examples of pattern specifications related to potential systematic defects include checks for necking, line pullback, thinning, critical dimension (CD), edge placement, overlap, resist top loss, resist undercut, and / or bridging. The process window of a pattern on a patterning device or area thereof can be obtained by merging (e.g., overlapping) the process windows of each individual pattern. The boundary of the process window of a group of patterns includes the boundaries of the process windows of some of the individual patterns. In other words, these individual patterns limit the process window of the group of patterns.

[0048]

[0061] As shown in FIG. 2, a lithography apparatus LA can form part of a lithography cell LC, often referred to as a lithocell or cluster, which also includes equipment for performing pre-exposure and post-exposure processes on a substrate. Conventionally, these include one or more spin coaters SC for depositing one or more resist layers, one or more developers for developing exposed resist, one or more chill plates CH, and / or one or more bake plates BK. A substrate handler, or robot RO, picks up one or more substrates from input / output ports I / O1 and I / O2, moves them between different process tools, and delivers them to the loading bay LB of the lithography apparatus. These tools, often collectively referred to as tracks, are under the control of a track control unit TCU, which itself is controlled by a supervisory control system SCS, which also controls the lithography apparatus via a lithography control unit LACU. In this manner, various tools can be operated to maximize throughput and processing efficiency.

[0049]

[0062] In order to ensure that substrates exposed by a lithographic apparatus are exposed accurately and consistently, and / or to monitor parts of a patterning process (e.g., a device manufacturing process) that includes at least one pattern transfer step (e.g., an optical lithography step), it may be desirable to inspect a substrate or other object to measure or determine one or more properties such as alignment, overlay (e.g., between structures on a higher layer, or between structures on the same layer that are provided separately on the same layer, e.g., by a double patterning process), linewidth, critical dimension (CD), focus offset, material properties, etc.

[0050]

[0063] The one or more measurement parameters may include, for example, alignment, overlay between successive layers formed in or on the patterned substrate, critical dimension (CD) (e.g., critical linewidth) of features formed in or on the patterned substrate, focus or focus error of the optical lithography process, dose or dose error of the optical lithography process, optical aberrations of the optical lithography process, etc. The measurements may be performed on targets on the product substrate itself and / or on dedicated metrology targets provided on the substrate. Measurements may be performed after resist development but before etching, after etching, after deposition, and / or at other times.

[0051]

[0064] Various techniques exist for measuring structures formed during patterning processes, including the use of scanning electron microscopes, image-based metrology tools, and / or various specialized tools. Any or all of these tools may include linear actuators with corresponding cooling systems. A fast, non-invasive type of specialized metrology tool is one in which a beam of radiation is directed at a target on the surface of a substrate, and properties of the scattered (diffracted / reflected) beam are measured. By evaluating one or more properties of the radiation scattered by the substrate, one or more properties of the substrate can be determined. This can be referred to as diffraction-based metrology. One application of this diffraction-based metrology is measuring the asymmetry of features within a target. This can be used, for example, as a measure of overlay, although other applications are known. For example, asymmetry can be measured by comparing opposite portions of a diffraction spectrum (e.g., comparing the -1st and +1st orders of the diffraction spectrum of a periodic grating).

[0052]

[0065] Metrology results may be provided directly or indirectly to the supervisory control system SCS. If errors are detected, adjustments may be made to the exposure of subsequent substrates (particularly if inspection can be performed immediately and one or more other substrates in the batch have not yet been exposed) and / or to subsequent exposures of exposed substrates. Also, already exposed substrates may be stripped and reworked to improve yield, or may be discarded, thereby avoiding further processing of substrates known to be defective. If only some target portions of a substrate are defective, further exposures may be performed only on those target portions that meet specifications.

[0053]

[0066] The cooling system and / or method may be used as a stand-alone tool and / or technique and / or in conjunction with semiconductor manufacturing equipment and / or processes to improve the accurate transfer of complex designs to a physical wafer. For example, the cooling system may be part of a linear actuator included in the lithography apparatus shown in FIG. 1 , included in one or more devices of a lithographic cell shown in FIG. 2 , and / or included in other equipment (semiconductor-related or unrelated). As described above, the cooling system includes a surface-wound electric coil and a cooling plate. The electric coil is configured to be energized to provide electromagnetic force for the linear actuator. The electric coil is configured to surround an armature of the linear actuator. The cooling plate is in thermal contact with the electric coil and configured to cool the electric coil. Each cooling plate is configured to surround the armature and is positioned between adjacent individual coils such that the electric coil and cooling plate form an alternating arrangement of plates and coils along the length of the armature.

[0054]

[0067] FIGS. 3-5 provide a basic explanation of various linear actuator-related terminology. For example, FIG. 3 illustrates an armature 300 with a surface-wound electrical coil 302 compared to an armature 350 with a racetrack-wound coil 352. The surface-wound electrical coil 302 includes a coil with windings that circulate around the armature 300 (around the y-axis in this example). The racetrack-wound coil 352 includes windings that are located on the surface of the armature 350 (around the z-axis in this example). FIG. 3 illustrates the racetrack-wound coil 352 surrounding a core 354. The core 354 may include a soft ferromagnetic magnet and / or other material. In some embodiments, the racetrack-wound coil 352 and corresponding core 354 may be coupled to the surface of the armature 350 (the top surface of the armature 350 parallel to the x-y plane in FIG. 3) and / or some other surface (which may act as the armature to provide mechanical support in this case). The dotted circle 375 in Figure 3 indicates windings or currents pointing out of the page, while the cross circle 385 indicates windings or currents pointing into the page. Armatures 300 and / or 350 may include structural members configured to mechanically support surface-wound electrical coils 302, racetrack-wound coils 352, cooling plates (described below), and / or other components. Armatures 300 and / or 350 may include a main current-carrying winding (e.g., coil 302 or 352) and form part of a linear actuator in which an electromotive force is induced. Armatures 300 and / or 350 may include, for example, soft ferromagnetic and / or other materials.

[0055]

[0068] FIG. 4 shows phase current distribution configurations for a linear actuator. It shows concentrated (N-phase) phase currents 400 and distributed phase currents 402. It shows surface-wound coils 302 with armature 300 and racetrack-wound coils with armature 350 (illustrated in the y-z plane). It also shows N-phase coil pitches 404, 406, 408, and 410. For concentrated phase currents 400, the currents in each phase have adjacent + / -x current directions. For distributed phase currents 402, the currents in each phase have spatially dispersed + / -x current directions. A linear actuator in a lithography apparatus may use a racetrack-wound coil 352 with concentrated phase currents 400 as a forcer (bottom left box; note that the coil is sandwiched between cooling plates oriented in the x-y plane). This cooling system allows for both concentrated and distributed winding configurations for surface-wound coils (top row in FIG. 4) in a linear actuator.

[0056]

[0069] FIG. 5 illustrates an exemplary three-phase current distribution configuration with linear actuator magnet tracks 500 and 502. FIG. 5 illustrates concentrated phase current 400 and distributed phase current 402 configurations for surface-wound coil 302 with armature 300 and racetrack-wound coil 352 with armature 350. Magnet track 500 has a magnet pitch 510 that is not the same as coil pitch 512 (a 2:1 pitch ratio (coil-to-magnet)), while magnet track 502 has a magnet pitch 520 that is the same as coil pitch 522 ("full pitch" distributed phase current). Note that FIG. 5 is merely exemplary, and many other configurations are possible (e.g., phases per actuator ≧3, pitch ratios other than 1:1 or 2:1, number of polarizations per magnet pitch ≧2 but ≠4 in a Halbach array, etc.). Additionally, linear actuator motors with surface-wound coils typically have double-sided surfaces (with two magnet tracks) to take advantage of both top and bottom current distribution. The surface wound configuration requires a 180° phase shift in the magnet polarization between the upper and lower tracks.

[0057]

[0070] FIG. 6 illustrates a cooling system 600 for a linear actuator, according to one embodiment. The linear actuator may be a Lorentz actuator, a linear actuator with magnetic material present in the armature, with or without slots or magnetic teeth in the armature, and / or other linear actuators. The cooling system 600 and linear actuator may form part of, for example, a lithography or metrology apparatus configured for semiconductor manufacturing processes and / or may have other applications. In such apparatus, conventional linear actuators typically include coils and / or cooling plates oriented "horizontally" (generally parallel to the top or bottom surface of the armature). In contrast, system 600 includes a cooling system with coils and cooling plates oriented "vertically" (generally perpendicular to the top or bottom surface of the armature). Benefits of this orientation include robust support for the coils, additional cooling surface relative to conventional linear actuators, and design freedom for routing electrical connections for a wide range of phase current distribution, which may be preferable for achieving high force density with reduced force ripple.

[0058]

[0071] The system 600 includes a plurality of surface-wound electric coils 602 configured to be energized to provide electromagnetic force for the linear actuator. The surface-wound electric coils 602 may be, for example, rectangular wire coils and / or other coils. The surface-wound electric coils 602 may be formed from copper and / or other materials. The plurality of surface-wound electric coils 602 are configured to surround an armature 604 of the linear actuator. The plurality of surface-wound electric coils 602 may include, for example, rectangular wire coils or toroidal wound coils. FIG. 6 also shows magnet tracks 630, 632 of the linear actuator on either side (above and below) of the surface-wound electric coils 602 and armature 604. In this embodiment, the pitch of the magnet tracks 630, 632 matches the pitch width 634 of the surface-wound electric coils 602.

[0059]

[0072] The system 600 includes a plurality of cooling plates 610 in thermal contact with the 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 thought of, for example, as a stack (e.g., laminated cooling plates 610). The cooling plates 610 are rigidly fastened to the armature 604, thereby providing mechanically robust support for 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. The individual plates of the plurality of cooling plates 610 are configured to surround the armature 604, with the plurality of surface-wound electrical coils 602 and the plurality of cooling plates 610 positioned between adjacent individual coils 602 to form an alternating array 620 of plates 610 and surface-wound electrical coils 602 along the length of the armature 604. Length may include, for example, a portion or the entire length of armature 604. Note that cooling plate 610 is in thermal contact with the edge of coil 602 (e.g., every winding is in direct contact with the surface of cooling plate 610).

[0060]

[0073] As shown in FIG. 6 , the plurality of cooling plates 610 have a generally rectangular cross-section 640 with one or more cooling channels 642 formed therein configured to carry a coolant. Note that the cooling plates 610 can have any cross-sectional shape and / or any number of channels 642 oriented in any configuration that enables them to function as described herein. The plurality of cooling plates 610 are configured to be coupled together such that the one or more cooling channels 642 carry a 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 with one or more cooling channels 642 and / or in-plane electrical wiring, regions for normal bus wiring, and / or regions for mechanical coupling to the armature 604, another plate 610, and / or surface-wound electrical coils 602.

[0061]

[0074] In some embodiments, the multiple surface-wound electrical coils 602 are configured to be soldered and / or otherwise coupled to one another via inner leads 650 routed through grooves 652 in the armature 604. Adjacent surface-wound electrical coils 602 may have opposite or the same winding direction, depending on the configuration. The multiple surface-wound electrical coils 602 also include outer leads 654 configured to couple, for example, in series with another surface-wound electrical coil 602, to couple with a junction between parallel phases, or to couple with an amplifier.

[0062]

[0075] In some embodiments, system 600 includes insulating material 660 and / or adhesive 661 positioned between the plurality of surface-wound electrical coils 602 and the plurality of cooling plates 610. Insulating material 660 may include Kapton, ceramic sheet, nylon sheet, Teflon sheet, any and / or any other corona-resistant polyimide. Generally, any material that can function as an electrical insulator between the coil windings and a metal (as an example material) cooling plate may include the insulating material. In some embodiments, the cooling plate itself may be an insulating ceramic material, or some material configured for thermal coupling may be between the cooling plate and the coil windings.

[0063]

[0076] In some embodiments, system 600 includes a cover and / or canning surface 670 configured to surround multiple surface-wound electrical coils 602, multiple cooling plates 610, armature 604, and / or other components of system 600. The canning surface may also provide additional mechanical support for one or more components of system 600. The canning surface may be a corrosion-resistant material (and may also be non-magnetic), such as stainless steel. The purpose of the canning surface is to prevent the ferromagnetic material from becoming embrittled due to chemical reaction. The can may be, for example, a welded box or may be deposited in some manner.

[0064]

[0077] As shown in FIG. 6 , the surface-wound electrical coils 602 and the cooling plates 610 are configured to be oriented in a plane generally perpendicular to the length of the armature 604. The surface-wound electrical coils 602 and the cooling plates 610 are configured to be separated into component parts. The generally perpendicular orientation of the surface-wound electrical coils 602 and the cooling plates 610 to the length of the armature 604 and / or the assembled nature of the surface-wound electrical coils 602 and the cooling plates 610 into separate parts are configured to reduce shear forces on the mechanical fasteners and / or adhesives (e.g., 661) joining any two surface-wound electrical coils 602 and / or cooling plates 610 along the length of the armature 604, compared to a parallel orientation and / or unitary structure of the surface-wound electrical coils 602 and the cooling plates 610. The glue layer can 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 function as a viscoelastic bond between two parts of the system (the coil and the insulated cooling plate) that have different coefficients of thermal expansion (CTE) but still need to transfer force to each other. The viscoelasticity of the glue layer allows for mechanical and thermal bonding even with the coil and cooling plate, which expand and contract by different amounts during force and thermal cycling due to their CTE mismatch. The glue layer can also serve as additional protection against dielectric breakdown between the coil and the optional metal cooling plate by eliminating voids (which can be helped by filling all negative space / thermal gap volume in the coil). In examples that optionally include a glue layer for the present system, the benefits of the viscoelastic bond still exist beyond simply holding the coil in place. Attempting to capture these benefits comes at the expense of the described performance improvements, so the choice is left to the designer's discretion (and is therefore optional).

[0065]

[0078] 7 illustrates an embodiment in which a stack 700 of surface-wound electrical coils 602 and plates 610 is configured to be mechanically preloaded 702 in the direction of linear actuator movement 704 (FIG. 7 shows reaction force 710) so as to reduce and / or eliminate the need for glue and / or potting between the coils 602 and a coil housing (which may optionally be included in system 600 such as that shown in FIG. 6) to couple the coils to the cooling plates during operation. The generally perpendicular orientation of the multiple cooling plates 610 to the length of the armature 604 is configured to reduce the distance D between the magnet track 630 of the linear actuator and the multiple surface-wound electrical coils 602, compared to a parallel orientation of the multiple cooling plates 610 (as in conventional systems including a laminated stack of coils and cooling plates).

[0066]

[0079] FIG. 8 shows cooling channels 642 (in the x-z plane in this illustration) in the cooling plate 610 connected to main inlet 800 / outlet 802 channels (pointing into / out of the page) that traverse the length of the linear actuator armature 604 and / or motor unit (in the y direction, also pointing into / out of the page; two channels per linear conductor section are arbitrarily shown in this illustration in the x direction). Note that the cooling channels can follow any path and do not necessarily follow a straight path along the length of the coil windings. The channel paths can be optimized, for example, to ensure that all windings in the coil overlap with cooling water at some point. The cooling surface 803 (the interface between the surface-wound electrical coil 602 and the cooling plate 610) is shown (indicated by the large arrow). It is at these locations that heat is transferred 820 from the coil 602 to the cooling plate 610. The configuration of system 600 ( FIG. 6 ) makes available additional cooling surfaces 804 toward the inner windings of surface-wound electric coil 602 facing armature 604. The inner windings of surface-wound electric coil 602 are in contact with armature 604, which can provide additional cooling surfaces. At these locations, heat is transferred 820 from surface-wound electric coil 602 to armature 604 across coil (or copper) height H (for the outermost windings of surface-wound electric coil 602, the thermal resistance of the armature can be more than 10 times higher than the thermal resistance of the windings adjacent cooling plate 610). Armature 604 can include additional, optional cooling channels 850 (two are optionally shown here) to carry heat transferred from the inner coil surface to armature 604.

[0067]

[0080] FIG. 9 illustrates an embodiment in which multiple surface-wound electrical coils 602 and multiple cooling plates 610 are configured for assembly 900, with alternating surface-wound electrical coils 602 and cooling plates 610 coupled together to form the cooling system 600. The stack 902 of surface-wound coils 602 and plates 610 is configured to be mechanically preloaded in the direction of linear actuator movement. FIG. 9 illustrates an exemplary assembly scheme that includes stacking the cooling plates 610 and surface-wound electrical coils 602 on a common armature 604 and sequentially soldering (and testing) the connections. The entire assembly can be compressed and held in place, for example, by tensioning rods and / or other methods. Controlled compression and / or other factors may allow for the elimination of a potting layer while maintaining good thermal contact between the electrical insulation on the cooling plates 610 and the surface-wound electrical coils 602. This also allows for easier disassembly and reuse of all operating components of the forcer for maintenance / refurbishment.

[0068]

[0081] As shown in FIG. 9, the cooling plate 610 need only be as wide as a single surface-wound electrical coil 602 and long enough to span the surface-wound electrical coil 602 plus the footprint for cooling and electrical bus connections and interface connections. This allows the individual cooling plates 610 required to be smaller than those typically used in conventional systems. Additionally, as discussed above (FIG. 8), the thickness of the cooling plate 610 no longer limits the magnetic gap (compared to conventional systems), which means that the cooling plate 610 can be thicker than those typically used in conventional systems (e.g., ~0.9 mm thick). This facilitates cheaper and easier manufacturing, among other advantages.

[0069]

[0082] 10 shows regions 1000, 1002 of the surface-wound electrical coils 602 / plates 610 configured to route electrical connections through the volume between the cooling plates 610 and to penetrate a cross section (e.g., in the x-z direction in this example) of the cooling plates 610 (e.g., in the y direction in this example). An inner lead 650 (within region 1000) may have a soldered connection to an adjacent surface-wound electrical coil 602 routed through a groove 652 or other hole in the armature 604. An outer lead 654 may be connected in series to another surface-wound electrical coil 602, to a junction between parallel phases, or to an amplifier through a bus connection made in the (three-dimensional) region 1002 beyond the ends of the surface-wound electrical coils 602. This arrangement allows for a relatively simple implementation of distributed phase currents. NOTE: One of the main benefits of using distributed phase currents is that it reduces spatial harmonics in the generated electromotive force of the forcer, thereby more efficiently using the available magnetic flux from the opposite side (mover or stator, e.g., Halbach magnet track) to generate thrust. The result should be a higher force density actuator with lower force ripple.

[0070]

[0083] FIG. 11 illustrates an exemplary three-phase forcer 1100 with a distributed current distribution 1102. The inner lead 650, outer lead 654, and / or multiple surface-wound electrical coils 602 are configured to achieve distributed phase current through overlapping windings 1104, 1106. For example, half-coil pairings can be used between cooling plates 610. As shown in FIG. 11, achieving distributed phase current typically requires overlapping wiring, which requires extra volume and solving a difficult 3D wiring puzzle. An advantage of the cooling system 600 (FIG. 6) is that distributed phase current can be achieved with flat wire coils without overlapping flat wire coils within the magnetic gap by simply connecting each phase to a bus that penetrates the motor volume along the motor's drive direction (y-axis). Furthermore, the number of additional cooling plates 610 and / or windings per phase can be selected as part of the inherent design freedom included with the system 600. 11 shows an exemplary five-phase actuator 1110 and an actuator package 1112 having several actuators 1110 connected in series. An actuator is a single group of phases (e.g., one group of individual R, S, and T phases in the case of a three-phase actuator) that make up one complete electrical cycle. An actuator package or assembly can be multiple three-phase actuators electrically coupled together (all R phases in parallel with each other, as well as S and T), or it can simply be several actuators mechanically packaged into one assembly.

[0071]

[0084] FIG. 12 illustrates an exemplary three-phase forcer with concentrated 1200 and distributed 1202 current distributions. The inner leads 650, outer leads 654, and / or multiple surface-wound electrical coils 602 are configured to achieve concentrated 1200 phase current using monocoils 602 stacked between cooling plates 610. While FIG. 12 illustrates half-coil pairings 1204 with five cooling plates 610 per phase 1206, any number of half-coil pairs and cooling plates 610 are possible per phase. This preserves design freedom to adjust the number of turns per phase and the number of cooling plates per phase to achieve optimal performance and / or has other advantages.

[0072]

[0085] 13 illustrates a cooling method for a linear actuator. The linear actuator may be a Lorentz actuator or an iron-core linear actuator with magnetic material present in the armature, with or without slots or magnetic teeth in the armature (as noted above, these may also be known as, for example, slotted iron-core LPMSMs (linear permanent magnet synchronous motors)). Method 1300 may be performed in a cooling system, for example, as described herein. The cooling system and linear actuator may form part of a lithography or metrology apparatus configured for a semiconductor manufacturing process, and / or part of another system.

[0073]

[0086] The operations of method 1300 presented below are intended to be illustrative. In some embodiments, method 1300 can be implemented with one or more additional operations not described and / or without one or more of the operations described. Furthermore, the order in which the operations of method 1300 are shown in FIG. 13 and described below is not intended to be limiting.

[0074]

[0087] In operation 1302, a multi-wound electrical coil is formed. The coil is configured to be energized to provide electromagnetic force for the linear actuator. The multi-wound electrical coil is configured to surround an armature of the linear actuator. The multi-wound electrical coil may include, for example, a surface-wound rectangular wire coil or a toroidal wound coil. The multi-wound electrical coil may be soldered to one another via an inner lead wire routed through a slot in the armature. The multi-wound electrical coil includes an outer lead wire configured to couple in series with another coil, to couple with a connection between parallel phases, or to couple with an amplifier. The inner lead wire, outer lead wire, and / or the multi-wound electrical coil are configured to achieve distributed phase current with overlapping windings. In some embodiments, the inner lead wire, outer lead wire, and / or the multi-wound electrical coil are configured to achieve concentrated phase current with coils stacked between cooling plates. In some embodiments, operation 1302 is performed by the same or similar multi-wound electrical coil and / or other components as the multi-wound electrical coil described above.

[0075]

[0088] In 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 plates of the plurality of cooling plates are configured to surround the armature and positioned between adjacent individual coils such that the plurality of wound electrical coils and the plurality of cooling plates form an alternating arrangement of plates and coils along the length of the armature. The length includes a portion or the entire length of the armature. In some embodiments, the plurality of cooling plates have a generally rectangular cross-section with one or more cooling channels formed therein configured to carry a coolant. In some embodiments, operation 1304 is performed by a plurality of cooling plates and / or other components the same as or similar to the plurality of cooling plates described above.

[0076]

[0089] In operation 1306, the multiple wound electrical coils and multiple cooling plates are oriented in a plane generally perpendicular to the length of the armature. In operation 1308, the multiple wound electrical coils and multiple cooling plates are assembled piece by piece, and alternating wound electrical coils and cooling plates are coupled together to form a cooling system. In operation 1310, the multiple cooling plates are configured to be coupled together such that one or more cooling channels carry coolant to cool the multiple wound electrical coils along the length of the armature. In some embodiments, operations 1306-1310 are performed by multiple wound electrical coils and / or multiple cooling plates and / or other components similar and / or the same as the coils and / or cooling plates described above.

[0077]

[0090] In some embodiments, the generally perpendicular orientation of the multiple wound electrical coils and multiple cooling plates relative to the length of the armature and / or the assembled nature of the multiple wound electrical coils and multiple cooling plates are configured to reduce shear forces on the mechanical fasteners and / or adhesives joining any two wound electrical coils and / or cooling plates along the length of the armature, compared to a parallel orientation and / or unitary structure of the multiple wound electrical coils and multiple cooling plates. In some embodiments, the stack of coils and plates is configured to be mechanically preloaded in the direction of linear actuator movement (FIG. 7 shows reaction force 710) to reduce and / or eliminate the need for glue and / or potting between the coil and coil housing (which may optionally be included in system 600 as shown in FIG. 6) to couple the coil to the cooling plate during operation.

[0078]

[0091] In some embodiments, a generally perpendicular orientation of the cooling plates to the length of the armature is configured to reduce the distance between the magnets and the ferromagnetic back iron of the linear actuator compared to a parallel orientation of the cooling plates. In some embodiments, the cooling plates include regions with one or more cooling channels and / or in-plane electrical wiring, regions for normal bus wiring, and / or regions for mechanical coupling to the armature, another plate, and / or coil.

[0079]

[0092] In operation 1312, insulation and / or adhesive may be positioned between the multiple wound electrical coils and the multiple cooling plates. The insulation may include Kapton, ceramic sheets, nylon sheets, Teflon sheets, and / or any other corona-resistant polyimide. Generally, any material that can function as an electrical insulator between the coil windings and a metal cooling plate (as an example of a material) may include the insulation. In some embodiments, the cooling plate itself may be an insulating ceramic material, or some material configured for thermal coupling may be between the cooling plate and the coil windings. Operation 1312 may also include providing a canning surface configured to surround the multiple wound electrical coils, the multiple cooling plates, and the armature. In some embodiments, operation 1312 is performed by the insulation, adhesive, and / or canning surface, and / or other components described herein.

[0080]

[0093] Various embodiments of the present system and method are disclosed in the following numbered clause list. 1. A multi-wound electrical coil configured to be energized to provide electromagnetic force for a linear actuator, the multi-wound electrical coil configured to surround an armature of the linear actuator; 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; Equipped with A cooling system for a linear actuator, wherein individual plates of a plurality of cooling plates are configured to surround an armature, with a plurality of wound electrical coils and a plurality of cooling plates positioned between adjacent individual coils to form an alternating arrangement of plates and coils along the length of the armature. 2. The system of clause 1, wherein 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. 3. A system as described in any one of clauses 1-2, wherein the plurality of wound electrical coils and the plurality of cooling plates are configured to be assembled in parts, and alternating wound electrical coils and cooling plates are coupled to one another to form a cooling system. 4. The system of any one of clauses 1-3, wherein the generally perpendicular orientation of the multiple wound electrical coils and multiple cooling plates relative to the length of the armature and / or the assembled nature of the multiple wound electrical coils and multiple cooling plates is configured to reduce shear forces on mechanical fasteners and / or adhesives joining any two wound electrical coils and / or cooling plates along the length of the armature compared to a parallel orientation and / or unitary structure of the multiple wound electrical coils and multiple cooling plates. 5. The system of any one of clauses 1-4, wherein the generally perpendicular orientation of the multiple cooling plates to the length of the armature is configured to reduce the distance between the magnets and the ferromagnetic back iron of the linear actuator compared to a parallel orientation of the cooling plates. 6. The system of any one of clauses 1-5, wherein the plurality of cooling plates have a generally rectangular cross-section with one or more cooling channels formed therein configured to carry a coolant. 7. The system of any one of clauses 1-6, wherein the plurality of cooling plates are configured to be coupled together such that one or more cooling channels carry coolant to cool the plurality of wound electrical coils along the length of the armature. 8. The system of any one of clauses 1-7, wherein the plurality of cooling plates includes an area with one or more cooling channels and / or in-plane electrical wiring, an area for normal bus wiring, and / or an area for mechanical coupling to an armature, another plate, and / or a coil. 9. The system of any one of clauses 1-8, wherein the multiple wound electrical coils are configured to be soldered together via inner leads routed through grooves in the armature. 10. The system of any one of clauses 1-9, wherein the multiple-wound electrical coil includes an outer lead configured to couple in series with another coil, to couple with a junction between parallel phases, or to couple with an amplifier. 11. A system as described in any one of clauses 1 to 10, wherein the inner lead wire, outer lead wire and / or multiple turn electrical coil are configured such that distributed phase current is achieved by overlapping windings. 12. The system of any one of clauses 1 to 11, wherein the inner lead, outer lead and / or multiple turn electrical coil are configured to achieve concentrated phase current using coils stacked between cooling plates. 13. The system of any one of clauses 1-12, further comprising an insulating material and / or adhesive positioned between the plurality of wound electrical coils and the plurality of cooling plates. 14. The system of any one of clauses 1-13, wherein the insulating material comprises Kapton, a ceramic sheet, a nylon sheet, a Teflon sheet, or another corona-resistant polyimide. 15. The system of any one of clauses 1-14, wherein the multiple wound electrical coils include a surface wound rectangular wire coil or a toroidal wound coil. 16. A system as described in any one of clauses 1 to 15, wherein the coil and plate stack is configured to be mechanically pre-stressed in the direction of movement of the linear actuator so as to eliminate the need for glue and / or potting between the coil and the coil housing to bond the coil to the cooling plate during operation. 17. The system of any one of clauses 1-16, further comprising a canning surface configured to surround the plurality of wound electrical coils, the plurality of cooling plates, and the armature. 18. A system as described in any one of clauses 1 to 17, wherein the linear actuator is a Lorentz actuator or a linear actuator in which there is magnetic material in the armature, with or without slots or magnetic teeth in the armature. 19. The system of any one of clauses 1-18, wherein the length includes a portion or the entire length of the armature. 20. A system according to any one of clauses 1 to 19, wherein the cooling system and the linear actuator form part of a lithography or metrology apparatus configured for a semiconductor manufacturing process. 21. Forming a multi-wound electrical coil configured to be energized to provide an electromagnetic force for a linear actuator, the multi-wound electrical coil configured to surround an armature of the linear actuator; forming a plurality of cooling plates and positioning them 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; Including, A cooling method for a linear actuator, wherein individual plates of a plurality of cooling plates are configured to surround an armature, with a plurality of wound electrical coils and a plurality of cooling plates positioned between adjacent individual coils to form an alternating arrangement of plates and coils along the length of the armature. 22. The method of clause 21, further comprising orienting the plurality of wound electrical coils and the plurality of cooling plates in a plane generally perpendicular to the length of the armature. 23. The method of any one of clauses 21-22, further comprising assembling the plurality of wound electrical coils and the plurality of cooling plates in parts, wherein alternating wound electrical coils and cooling plates are coupled together to form a cooling system. 24. The method of any one of clauses 21-23, wherein the generally perpendicular orientation of the multiple wound electrical coils and multiple cooling plates relative to the length of the armature and / or the assembled nature of the multiple wound electrical coils and multiple cooling plates is configured to reduce shear forces on mechanical fasteners and / or adhesives joining any two wound electrical coils and / or cooling plates along the length of the armature compared to a parallel orientation and / or unitary construction of the multiple wound electrical coils and multiple cooling plates. 25. The method of any one of clauses 21-24, wherein a generally perpendicular orientation of the multiple cooling plates to the length of the armature is configured to reduce the distance between the magnets and the ferromagnetic back iron of the linear actuator compared to a parallel orientation of the cooling plates. 26. The method of any one of clauses 21-25, wherein the plurality of cooling plates have a generally rectangular cross-section with one or more cooling channels formed therein that are configured to carry a coolant. 27. The method of any one of clauses 21-26, further comprising coupling a plurality of cooling plates together such that one or more cooling channels carry coolant for cooling a plurality of wound electrical coils along the length of the armature. 28. The method of any one of clauses 21-27, wherein the plurality of cooling plates includes areas with one or more cooling channels and / or in-plane electrical wiring, areas for normal bus wiring, and / or areas for mechanical coupling to an armature, another plate, and / or coil. 29. The method of any one of clauses 21-28, further comprising soldering the plurality of wound electrical coils together via inner leads routed through grooves in the armature. 30. The method of any one of clauses 21-29, wherein the multiple-wound electrical coil includes an outer lead configured to couple in series with another coil, to couple with a junction between parallel phases, or to couple with an amplifier. 31. The method of any one of clauses 21 to 30, wherein the inner lead wire, the outer lead wire and / or the multiple-wound electrical coil are configured such that dispersed phase current is achieved by overlapping windings. 32. The method of any one of clauses 21 to 31, wherein the inner lead wire, outer lead wire and / or multi-wound electrical coil are configured such that concentrated phase current is achieved using coils stacked between cooling plates. 33. The method of any one of clauses 21-32, further comprising positioning insulation and / or adhesive between the plurality of wound electrical coils and the plurality of cooling plates. 34. The method of any one of clauses 21-33, wherein the insulating material comprises Kapton, a ceramic sheet, a nylon sheet, a Teflon sheet, or another corona-resistant polyimide. 35. The method of any one of clauses 21-34, wherein the multiple wound electrical coil comprises a surface wound rectangular wire coil or a toroidal wound coil. 36. A method according to any one of clauses 21 to 35, wherein the coil and plate stack is configured to be mechanically pre-stressed in the direction of movement of the linear actuator so as to eliminate the need for glue and / or potting between the coil and the coil housing to bond the coil to the cooling plate during operation. 37. The method of any one of claims 21-36, further comprising providing a canning surface configured to surround the plurality of wound electrical coils, the plurality of cooling plates, and the armature. 38. A method according to any one of clauses 21 to 37, wherein the linear actuator is a Lorentz actuator or a linear actuator in which there is magnetic material in the armature, with or without slots or magnetic teeth in the armature. 39. The method of any one of clauses 21 to 38, wherein the length includes a portion or the entire length of the armature. 40. The method of any one of clauses 21 to 39, wherein the cooling system and the linear actuator form part of a lithography or metrology apparatus configured for a semiconductor manufacturing process. 41. A lithography apparatus configured for a semiconductor manufacturing process, comprising: A linear actuator; a cooling system for the linear actuator; The cooling system comprises: a plurality of turn electrical coils configured to be energized to provide electromagnetic force for the linear actuator, the plurality of turn electrical coils being configured to surround an armature of the linear actuator; 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; Equipped with A lithographic apparatus, wherein each plate of the plurality of cooling plates is configured to surround an armature, and wherein the plurality of wound electrical coils and the plurality of cooling plates are positioned between adjacent individual coils to form an alternating arrangement of plates and coils along the length of the armature.

[0081]

[0094] While the concepts disclosed herein can be used with linear actuators associated with wafer fabrication on substrates such as silicon wafers, it should be understood that the disclosed concepts can be used with any type of fabrication system that can include a linear actuator (e.g., those used for fabrication on substrates other than silicon wafers). Additionally, combinations and subcombinations of the disclosed elements can comprise separate embodiments. For example, a cooling system and an associated lithographic apparatus including the cooling system can comprise separate embodiments, and / or these features can be used together in the same embodiment.

[0082]

[0095] The above description is intended to be illustrative rather than limiting, and as such, it will be apparent to one skilled in the art that modifications can be made as described herein without departing from the scope of the claims set out below.

Claims

1. a plurality of turn electrical coils configured to be energized to provide electromagnetic force for the linear actuator, the plurality of turn electrical coils being configured to surround an armature of the linear actuator; 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; Equipped with 1. A cooling system for a linear actuator, wherein each plate of the plurality of cooling plates is configured to surround the armature, and wherein the plurality of wound electrical coils and the plurality of cooling plates are positioned between adjacent individual coils such that they form an alternating arrangement of plates and coils along the length of the armature.

2. The system of claim 1 , wherein 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.

3. 2. The system of claim 1, 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 together to form the cooling system.

4. 10. The system of claim 1, wherein the generally perpendicular orientation of the plurality of wound electrical coils and the plurality of cooling plates relative to the length of the armature and / or the individual piece-assembled nature of the plurality of wound electrical coils and the plurality of cooling plates is configured to reduce shear forces on mechanical fasteners and / or adhesives joining any two wound electrical coils and / or cooling plates along the length of the armature compared to a parallel orientation and / or unitary structure of the plurality of wound electrical coils and the plurality of cooling plates.

5. 10. The system of claim 1, wherein a generally perpendicular orientation of the cooling plate to the length of the armature is configured to reduce a distance between a magnet and a ferromagnetic back iron of the linear actuator compared to a parallel orientation of the cooling plate.

6. 2. The system of claim 1, wherein the plurality of cooling plates have a generally rectangular cross-section with one or more cooling channels formed therein configured to carry a coolant, the plurality of cooling plates being 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. 10. The system of claim 1, wherein the plurality of cooling plates include areas with one or more cooling channels and / or in-plane electrical wiring, areas for normal bus wiring, and / or areas for mechanical coupling to the armature, another plate, and / or coil.

8. the plurality of wound electrical coils are configured to be soldered together via inner leads routed through grooves in the armature; the inner lead, the outer lead, and / or the plurality of turn electrical coils are configured such that a distributed phase current is achieved by overlapping windings; 10. The system of claim 1, wherein the inner lead, the outer lead, and / or the multiple turn electrical coil are configured to achieve concentrated phase current using coils stacked between cooling plates.

9. the multiple-wound electrical coil includes an outer lead configured to couple in series with another coil, to couple with a junction between parallel phases, or to couple with an amplifier; the inner lead, the outer lead, and / or the plurality of turn electrical coils are configured such that a distributed phase current is achieved by overlapping windings; 10. The system of claim 1, wherein the inner lead, the outer lead, and / or the multiple turn electrical coil are configured to achieve concentrated phase current using coils stacked between cooling plates.

10. 10. The system of claim 1, further comprising an insulating material and / or adhesive positioned between the plurality of wound electrical coils and the plurality of cooling plates, the insulating material comprising Kapton, a ceramic sheet, a nylon sheet, a Teflon sheet, or another corona-resistant polyimide.

11. The plurality of wound electric coils include a surface wound flat wire coil or a toroidal wound coil; 10. The system of claim 1, 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 glue and / or potting between the coil and coil housing to couple the coil to the cooling plate during operation.

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

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

14. forming a plurality of wound electrical coils configured to be energized to provide electromagnetic force for a linear actuator, the plurality of wound electrical coils configured to surround an armature of the linear actuator; forming a plurality of cooling plates and positioning them 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; Including, 1. A cooling method for a linear actuator, wherein each plate of the plurality of cooling plates is configured to surround the armature, and wherein the plurality of wound electrical coils and the plurality of cooling plates are positioned between adjacent individual coils so as to form an alternating arrangement of plates and coils along the length of the armature.

15. 1. A lithographic apparatus configured for a semiconductor manufacturing process, comprising: A linear actuator; a cooling system for the linear actuator; The cooling system comprises: a plurality of turn electrical coils configured to be energized to provide electromagnetic force for the linear actuator, the plurality of turn electrical coils being configured to surround an armature of the linear actuator; 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; Equipped with 11. A lithographic apparatus, wherein each plate of the plurality of cooling plates is configured to surround the armature, and wherein the plurality of wound electrical coils and the plurality of cooling plates are positioned between adjacent individual coils such that they form an alternating arrangement of plates and coils along the length of the armature.

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