Thermally Actuated Cooling System

Abstract

Systems, devices, and methods are provided for manufacturing a thermally actuated cooling device. An exemplary method can include providing a cooling member. The cooling member can include a contact plate, a fin extending from the contact plate in a first direction, and a protrusion extending from the contact plate in a second direction. The exemplary method can then include attaching the protrusion to a portion of an extreme ultraviolet (EUV) radiation source. The contact plate can include a first coefficient of thermal expansion (CTE) greater than a second CTE of the portion.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. patent application Ser. No. 63 / 335,118, filed April 26, 2022, entitled "THERMALLY ACTUATED COOLING SYSTEM," the entirety of which is incorporated by reference into this application.

[0002]

[0002] The present disclosure relates to thermally actuated cooling systems, apparatus, and methods of manufacture. [Background technology]

[0003]

[0003] A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. Lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such a case, a patterning device, sometimes referred to as a mask or reticle, can be used to generate a circuit pattern to be formed on an individual layer of the IC being formed. This pattern can be transferred onto a target portion (e.g. comprising part of one or several dies) on the substrate (e.g. a silicon wafer). Transfer of the pattern is usually by imaging onto a layer of radiation-sensitive material (e.g. resist) provided on the substrate. Typically, a single substrate will contain a network of adjacent target portions that are successively patterned. Conventional lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing the entire pattern onto the target portion at once, and so-called scanners, in which each target portion is irradiated by scanning the pattern with a radiation beam in a given direction (the "scan" direction) while synchronously scanning the target portion parallel or anti-parallel (e.g. opposite) to the given direction (the "scan" direction). It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.

[0004]

[0004] Due to continuous improvements in semiconductor manufacturing processes, for decades the number of functional elements such as transistors per device has been steadily increasing while the dimensions of the circuit elements have been continuously decreasing, following a trend commonly referred to as Moore's Law. To keep up with Moore's Law, the semiconductor industry is pursuing technologies that allow the creation of ever smaller features. To project a pattern onto a substrate, a lithography apparatus may use electromagnetic radiation. The wavelength of this radiation determines the minimum size of the features that are patterned on the substrate. Common wavelengths currently in use are 365 nm (i-line), 248 nm, 193 nm, and 13.5 nm.

[0005]

[0005] Extreme ultraviolet (EUV) radiation (e.g., electromagnetic radiation having a wavelength of about 50 nanometers (nm) or less (sometimes referred to as soft x-rays), including light with a wavelength of about 13.5 nm) may be used in or with lithographic apparatus to produce extremely small features in or on a substrate (e.g., a silicon wafer). Lithographic apparatus using EUV radiation having a wavelength in the range of 4 nm to 20 nm (e.g., 6.7 nm or 13.5 nm) can be used to form smaller features on a substrate compared to lithographic apparatus using radiation having a wavelength of, for example, 193 nm.

[0006]

[0006] Methods of generating EUV light include, but are not necessarily limited to, converting a material having an element with an emission line in the EUV region, such as xenon (Xe), lithium (Li), or tin (Sn), into a plasma state. For example, in one such method, called laser-produced plasma (LPP), the plasma may be generated by irradiating a target material (which in the context of an LPP source is synonymously referred to as fuel), for example in the form of a droplet, plate, tape, stream, or cluster of material, with an amplified light beam, which may be referred to as a drive laser. For this process, the plasma is typically generated in a closed vessel (e.g., a vacuum chamber) and monitored using various types of metrology instruments. Summary of the Invention

[0007] This disclosure describes various aspects of systems, apparatus, and methods for manufacturing and using a thermally actuated cooling system in an extreme ultraviolet (EUV) radiation source.

[0008] In some aspects, the present disclosure describes a system. The system can include a cooling member. The cooling member can include a contact plate, a fin extending from the contact plate in a first direction, and a protrusion extending from the contact plate in a second direction and configured to couple the contact plate to a portion of the EUV radiation source. The portion can include a heating element. The contact plate can include a first coefficient of thermal expansion (CTE) greater than a second CTE of the portion.

[0009] In some aspects, the present disclosure describes an apparatus. The apparatus can include a contact plate and a protrusion extending from the contact plate and configured to couple the contact plate to a portion of an EUV radiation source. The protrusion is configured to be in a physical strain relationship with the portion such that when the portion is heated, a first surface of the contact plate is configured to move away from a second surface of the portion, and when the portion is not exposed to heat, the first surface of the contact plate is configured to contact the second surface of the portion.

[0010] In some aspects, the present disclosure describes a method for manufacturing an apparatus. The method can include providing a cooling member. The cooling member can include a contact plate, a fin extending from the contact plate in a first direction, and a protrusion extending from the contact plate in a second direction. The method can further include attaching the protrusion to a portion of the EUV radiation source. The contact plate can include a first CTE that is greater than a second CTE of the portion. In some aspects, a first surface of the contact plate is configured to move away from a second surface of the portion when the portion is exposed to heat.

[0011]

[0011] Further features and the structure and operation of various aspects are described in detail below with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to the specific aspects described herein. Such aspects are presented herein for illustrative purposes only. Further aspects will be apparent to those skilled in the art based on the teachings contained herein. [Brief description of the drawings]

[0012]

[0012] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate the present disclosure and, together with the description, further serve to explain the principles of aspects of the disclosure and to enable those skilled in the art to make and use aspects of the disclosure.

[0013]

[0013] [Figure 1A] 1 is a schematic diagram of an exemplary reflective lithographic apparatus according to some aspects of the present disclosure.

[0014] [Figure 1B] 1 is a schematic diagram of an exemplary transmissive lithographic apparatus according to some aspects of the present disclosure.

[0015] [Diagram 2] FIG. 1B is a more detailed schematic diagram of the reflective lithographic apparatus shown in FIG. 1A according to some embodiments of the present disclosure.

[0016] [Diagram 3] 1 is a schematic diagram of an exemplary lithography cell according to some aspects of the present disclosure.

[0017] [Figure 4] 1 is a schematic diagram of an example radiation source for an example reflective lithographic apparatus according to some aspects of the present disclosure;

[0018] [Figure 5A] 1 is a schematic diagram of an example thermally actuated cooling system according to some aspects of the present disclosure. [Figure 5B] FIG. 1 is a schematic diagram of an exemplary thermally actuated cooling system according to some aspects of the present disclosure.

[0019] [Figure 6]FIG. 2 is a graphical illustration of an exemplary conceptual cooling profile resulting from the addition of an exemplary thermally actuated cooling system to a portion of a lithographic apparatus, in accordance with some aspects of the present disclosure.

[0020] [Figure 7] 1 is an exemplary method for manufacturing a device according to some aspects or portions of the present disclosure.

[0021] [Figure 8] 1 is an exemplary computer system for implementing some aspects or portions of the present disclosure.

[0014]

[0022] Features and advantages of the present disclosure will become more apparent from the detailed description set forth below in conjunction with the drawings, in which like reference numbers identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and / or structurally similar elements, unless otherwise indicated. More generally, the left-most digit(s) of a reference number identify the figure in which that reference number first appears. Unless otherwise indicated, the drawings provided throughout this disclosure should not be construed as drawings to scale. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015]

[0023] This specification discloses one or more embodiments incorporating features of the present disclosure. The disclosed one or more embodiments are merely illustrative of the present disclosure. The scope of the present disclosure is not limited to the disclosed one or more embodiments. The breadth and scope of the present disclosure are defined by the claims appended hereto and their equivalents.

[0016]

[0024] References to one or more described embodiments and to "one embodiment," "an embodiment," "an exemplary embodiment," "an example embodiment," or the like herein indicate that one or more described embodiments may include a particular feature, structure, or characteristic, but that not all embodiments necessarily include that particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in the context of one embodiment, it is understood that it is within the knowledge of one of ordinary skill in the art to affect such feature, structure, or characteristic in the context of other embodiments, whether or not expressly described.

[0017]

[0025] Spatially relative terms such as "beneath," "below," "lower," "above," "on," "upper," and the like, may be used herein to facilitate the description of the relationship of one element or feature to another element or features as shown in the figures. The spatially relative terms are intended to encompass various orientations of the device during use or operation in addition to the orientation shown in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may be similarly interpreted accordingly.

[0018]

[0026] The term "about" as used herein refers to a given quantity value that may vary based on the particular technique. Based on the particular technique, the term "about" can refer to a given quantity value that varies, for example, within a range of 10% to 30% of the value (e.g., ±10%, ±20%, or ±30% of the value).

[0019] overview

[0027] In some embodiments, EUV radiation source components, such as the droplet generator assembly (DGA), must be cooled before they can be serviced. In one example, a heat sink can be used to dissipate heat from the EUV radiation source by using two thermally mismatched materials in contact with each other, such as a heat sink made of a material that has good heat dissipation properties and is interdigitatedly engaged with the heat-generating component. In another example, natural convection, forced convection, fins, or Peltier elements (e.g., thermoelectric elements) can be utilized to cool the EUV radiation source.

[0020]

[0028] However, these techniques often require additional power or flow inputs. For example, adding cooling water to cool the DGA would result in excessive vibration that would adversely affect droplet stability. In another example, adding fins to the DGA to enhance convection would require additional power during operation to maintain operating temperatures, placing further strain on the electrical infrastructure and unnecessarily wasting energy.

[0021]

[0029] Furthermore, the cooling times using these techniques are too long and increase system downtime. For example, some components on the EUV radiation source operate above touch-safe temperatures and must be cooled before maintenance operations. This cooling time often takes more than an hour, increasing the mean time to repair (MTTR) and machine downtime.

[0022]

[0030] In contrast, some embodiments of the present disclosure can provide a thermally actuated cooling system that includes a heat sink with fins and a threaded post with a stainless steel insert that torque-fits onto a heat-generating EUV component, such as a DGA, causing distortion. When heated, the heat sink expands, and when the threads are relaxed, the heat sink lifts off the heat-generating EUV component.

[0023]

[0031] In some aspects, the present disclosure provides a thermally actuated cooling system including a cooling member coupled to a molybdenum member by a threaded projection partially surrounded by an insert and received in a receptacle in the molybdenum member, the cooling member including a contact plate and a rod extending therefrom having a higher CTE than the molybdenum, the threaded projection being in a physical strain relationship with the molybdenum member such that heating causes a contact plate surface to move away from the molybdenum member surface and cooling causes the contact plate surface to contact the molybdenum member surface to cool the molybdenum member.

[0024]

[0032] The thermally actuated cooling systems, apparatus, and methods disclosed herein have many example aspects. For example, aspects of the present disclosure provide faster cool down times for cooling components associated with an EUV radiation source in preparation for servicing operations. In yet another example, the present disclosure provides reduced MTTR and mean time between failures (MTBI).

[0025]

[0033] Before describing such aspects in greater detail, however, it is helpful to present an example environment in which aspects of the present disclosure can be implemented.

[0026] Exemplary Lithography System

[0034] 1A and 1B are schematic diagrams of lithographic apparatus 100 and lithographic apparatus 100', respectively, in which aspects of the present disclosure may be implemented. As shown in FIG. 1A and 1B, lithographic apparatus 100 and 100' are shown from a perspective (e.g., a side view) perpendicular to the XZ plane (e.g., the X axis points to the right, the Z axis points up, and the Y axis points into the page, away from the viewer), and patterning device MA and substrate W are shown from another perspective (e.g., a top view) perpendicular to the XY plane (e.g., the X axis points to the right, the Y axis points up, and the Z axis points out of the page, towards the viewer).

[0027]

[0035] In some aspects, lithographic apparatus 100 and / or lithographic apparatus 100' may include one or more of the following structures: an illumination system IL (e.g., an illuminator) configured to condition radiation beam B (e.g., a deep ultraviolet (DUV) radiation beam or an extreme ultraviolet (EUV) radiation beam), a support structure MT (e.g., a mask table) configured to support a patterning device MA (e.g., a mask, a reticle, or a dynamic patterning device) and connected to a first positioner PM configured to accurately position the patterning device MA, and a substrate holder such as a substrate table WT (e.g., a wafer table) configured to hold a substrate W (e.g., a resist coated wafer) and connected to a second positioner PW configured to accurately position the substrate W. Lithographic apparatuses 100 and 100' also have a projection system PS (e.g., a refractive projection lens system) configured to project a pattern imparted to radiation beam B by patterning device MA onto a target portion C of the substrate W (e.g., a portion comprising one or more dies). In lithographic apparatus 100, the patterning device MA and the projection system PS are reflective. In lithographic apparatus 100', the patterning device MA and the projection system PS are transmissive.

[0028]

[0036] In some aspects, during operation, the illumination system IL may receive a radiation beam from a radiation source SO (e.g., via a beam delivery system BD shown in FIG. 1B). The illumination system IL may include various types of optical structures, such as refractive, reflective, catadioptric, magnetic, electromagnetic, electrostatic, and other types of optical components, or any combination thereof, to guide, shape, or control the radiation. In some aspects, the illumination system IL may be configured to condition the radiation beam B to have a desired spatial and angular intensity distribution in cross-section, in the plane of the patterning device MA.

[0029]

[0037] In some aspects, the support structure MT can hold the patterning device MA in a manner that depends on the orientation of the patterning device MA relative to a reference frame, the design of at least one of the lithographic apparatuses 100 and 100', and other conditions, such as whether the patterning device MA is held in a vacuum environment or not. The support structure MT can use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterning device MA. The support structure MT can be, for example, a frame or a table and can be fixed or movable as required. By using sensors, the support structure MT can ensure that the patterning device MA is at a desired position, for example with respect to the projection system PS.

[0030]

[0038] The term "patterning device" MA should be interpreted broadly to refer to any device that can be used to impart a radiation beam B with a pattern in its cross-section, such as to create a pattern in a target portion C of a substrate W. The pattern imparted to the radiation beam B may correspond to a particular functional layer in the device being created in the target portion C to form an integrated circuit.

[0031]

[0039] In some aspects, the patterning device MA may be transmissive (as in the case of lithographic apparatus 100′ of FIG. 1B) or reflective (as in the case of lithographic apparatus 100 of FIG. 1A). The patterning device MA may include various structures, such as a reticle, a mask, a programmable mirror array, a programmable LCD panel, other suitable structures, or combinations thereof. The mask may include mask types such as binary, alternating phase-shift, or attenuated phase-shift, as well as various hybrid mask types. In one example, the programmable mirror array may include a matrix arrangement of small mirrors, each of which may be individually tilted to reflect an incoming radiation beam in different directions. The tilted mirrors may impart a pattern to a radiation beam B, which is reflected by the matrix of small mirrors.

[0032]

[0040] The term "projection system" PS is intended to be broadly interpreted and can encompass any type of projection system including refractive, reflective, catadioptric, magnetic, anamorphic, electromagnetic, and electrostatic optical systems, or any combination thereof, as appropriate, depending on the exposure radiation used and / or other factors such as the use of an immersion liquid (e.g. on the substrate W) or the use of a vacuum. A vacuum environment may be used for EUV or electron beam radiation, as other gases may absorb excess radiation or electrons. Thus, a vacuum environment may be provided throughout the beam path using a vacuum wall and vacuum pumps. Additionally, the use of the term "projection lens" herein may in some aspects be interpreted as synonymous with the more general term "projection system" PS.

[0033]

[0041] In some aspects, lithographic apparatus 100 and / or lithographic apparatus 100' may be of a type having two (e.g. "dual stage") or more substrate tables WT and / or two or more mask tables. In such a "multi-stage" machine, the further substrate tables WT may be used in parallel, or preparation steps may be performed on one or more tables while one or more other substrate tables WT are being used for exposure. In one example, preparation steps for a subsequent exposure of a substrate W may be performed on a substrate W located on one substrate table WT while another substrate W located on another substrate table WT is being used to expose a pattern on another substrate W. In some aspects, the further table may not be a substrate table WT.

[0034]

[0042] In some aspects, in addition to the substrate table WT, lithographic apparatus 100 and / or lithographic apparatus 100' may include a measurement stage. The measurement stage may be arranged to hold a sensor. The sensor may be arranged to measure a property of the projection system PS, a property of the radiation beam B, or both. In some aspects, the measurement stage may hold multiple sensors. In some aspects, the measurement stage may be moved to underneath the projection system PS when the substrate table WT is moved away from the projection system PS.

[0035]

[0043] In some aspects, lithographic apparatus 100 and / or lithographic apparatus 100' may be of a type in which at least a portion of the substrate may be covered by a liquid having a relatively high refractive index (e.g., water) to fill a space between the projection system PS and the substrate W. Immersion liquid may also be provided in other spaces in the lithographic apparatus, for example between the patterning device MA and the projection system PS. Immersion techniques provide for increasing the numerical aperture of the projection system. As used herein, the term "immersion" does not mean that a structure such as a substrate must be submerged in liquid, but simply that a liquid is located between the projection system and the substrate during exposure. Various immersion techniques are described in U.S. Patent No. 6,952,253, entitled "LITHOGRAPHIC APPARATUS AND DEVICE MANUFACTURING METHOD," issued on October 4, 2005, which is incorporated herein by reference in its entirety.

[0036]

[0044] 1A and 1B, the illumination system IL receives a radiation beam B from a radiation source SO. The radiation source SO and the lithographic apparatus 100 or 100' may be separate physical entities, for example if the radiation source SO is an excimer laser. In such a case, the radiation source SO is not considered to form part of the lithographic apparatus 100 or 100' and the radiation beam B passes from the radiation source SO to the illumination system IL using a beam delivery system BD (e.g. as shown in FIG. 1B) including, for example, suitable directing mirrors and / or beam expanders. In other cases, the radiation source SO may be an integral part of the lithographic apparatus 100 or 100', for example if the radiation source SO is a mercury lamp. The radiation source SO and the illuminator IL, together with the beam delivery system BD if necessary, may be referred to as a radiation system.

[0037]

[0045] In some aspects, the illumination system IL may include an adjuster AD for adjusting the angular intensity distribution of the radiation beam. Generally, at least the outer and / or inner radial extent (commonly referred to as "σ-outer" and "σ-inner", respectively) of the intensity distribution in a pupil plane of the illuminator may be adjusted. In addition, the illumination system IL may include various other components, such as an integrator IN and a radiation collector CO (e.g. a condenser or collector system). In some aspects, the illumination system IL may be used to adjust the radiation beam B to have a desired uniformity and intensity distribution in its cross-section.

[0038]

[0046] 1A, in operation, radiation beam B may be incident on patterning device MA (e.g. a mask, a reticle, a programmable mirror array, a programmable LCD panel, any other suitable structure or combination thereof), which may be held on support structure MT (e.g. a mask table), and may be patterned according to a pattern (e.g. a design layout) present on patterning device MA. In lithographic apparatus 100, radiation beam B may be reflected from patterning device MA. After traversing patterning device MA (e.g. after being reflected from patterning device MA), radiation beam B may pass through projection system PS, which may focus radiation beam B onto a target portion C of substrate W, or a sensor disposed on the stage.

[0039]

[0047] In some aspects, using the second positioner PW and a position sensor IF2 (e.g. an interferometric device, a linear encoder or a capacitance sensor), the substrate table WT can, for example, be accurately moved to position various target portions C in the path of the radiation beam B. Similarly, using the first positioner PM and another position sensor IF1 (e.g. an interferometric device, a linear encoder or a capacitance sensor), the patterning device MA can be accurately positioned with respect to the path of the radiation beam B.

[0040]

[0048] In some aspects, patterning device MA and substrate W may be aligned using mask alignment marks M1 and M2 and substrate alignment marks P1 and P2. Although Figures 1A and 1B show substrate alignment marks P1 and P2 as occupying dedicated target portions, substrate alignment marks P1 and P2 may be located in spaces between target portions. When substrate alignment marks P1 and P2 are located between target portions C, they are known as scribe-line alignment marks. Substrate alignment marks P1 and P2 may also be located in the target portion C areas as in-die marks. These in-die marks may be used as metrology marks, e.g. for overlay measurements.

[0041]

[0049] In some embodiments, for purposes of illustration and not limitation, one or more of the figures herein may utilize a Cartesian coordinate system. The Cartesian coordinate system includes three axes: an X axis, a Y axis, and a Z axis. Each of the three axes is orthogonal to the other two axes (e.g., the X axis is orthogonal to the Y and Z axes, the Y axis is orthogonal to the X and Z axes, and the Z axis is orthogonal to the X and Y axes). Rotation about the X axis is referred to as an Rx rotation. Rotation about the Y axis is referred to as an Ry rotation. Rotation about the Z axis is referred to as an Rz rotation. In some embodiments, the X and Y axes define a horizontal plane, while the Z axis is vertical. In some embodiments, the orientation of the Cartesian coordinate system may be different, for example, such that the Z axis has a component along the horizontal plane. In some embodiments, another coordinate system may be used, such as a cylindrical coordinate system.

[0042]

[0050] 1B, the radiation beam B is incident on a patterning device MA held on a support structure MT and is patterned by the patterning device MA. After traversing 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. In some embodiments, the projection system PS may have a pupil conjugate to the illumination system IPU pupil. In some embodiments, a portion of the radiation may diverge from the intensity distribution in the illumination system pupil IPU and traverse the mask pattern without being subject to diffraction in the mask pattern MP to generate an image of the intensity distribution in the illumination system pupil IPU.

[0043]

[0051] The projection system PS projects an image of the mask pattern MP onto a resist layer coated on the substrate W, the image being formed by diffracted beams generated from the mask pattern MP by radiation from the intensity distribution. For example, the mask pattern MP may include an array of lines and spaces. Diffraction of radiation different from the zeroth diffraction order in the array generates diffracted beams redirected by a change in direction perpendicular to the lines. The reflected light (e.g., the zeroth diffraction order beam) traverses the pattern without a change in propagation direction. The zeroth diffraction order beam traverses an upper lens or an upper lens group of the projection system PS, which is upstream of the pupil conjugate PPU of the projection system PS, to reach the pupil conjugate PPU. The part of the intensity distribution associated with the zeroth diffraction order beam, which is in the plane of the pupil conjugate PPU, is an image of the intensity distribution in the illumination system pupil IPU of the illumination system IL. In some embodiments, the aperture device PD may be located in or substantially in a plane that includes the pupil conjugate PPU of the projection system PS.

[0044]

[0052] The projection system PS is arranged to capture the zeroth order diffracted beam as well as the first or more than first order diffracted beams (not shown) using a lens or lens group. Some aspects are described in U.S. Patent No. 7,511,799, issued March 31, 2009, entitled "LITHOGRAPHIC PROJECTION APPARATUS AND A DEVICE MANUFACTURING METHOD," which is incorporated herein by reference in its entirety.

[0045]

[0053] In some aspects, using the second positioner PW and a position sensor IFD (e.g. an interferometric device, a linear encoder or a capacitance sensor), the substrate table WT can be accurately moved to, for example, position the various target portions C at focused and aligned positions in the path of the radiation beam B. Similarly, (e.g. after a machine search of a mask library or during a scan) the first positioner PM and another position sensor (e.g. an interferometric device, a linear encoder or a capacitance sensor) (not shown in FIG. 1B ) can be used to accurately position the patterning device MA with respect to the path of the radiation beam B. The patterning device MA and substrate W can be aligned using mask alignment marks M1 and M2 and substrate alignment marks P1 and P2.

[0046]

[0054] In general, movement of the support structure MT may be realized using a long-stroke positioner (coarse positioning) and a short-stroke positioner (fine positioning), which form part of the first positioner PM. Similarly, movement of the substrate table WT may be realized using a long-stroke positioner and a short-stroke positioner, 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 mask alignment marks M1 and M2 and substrate alignment marks P1 and P2. The substrate alignment marks (as shown) occupy dedicated target portions, but may be located in spaces between the target portions (e.g. scribe-line alignment marks). Similarly, in situations in which more than one die is provided on the patterning device MA, the mask alignment marks M1 and M2 may be located between the dies.

[0047]

[0055] The support structure MT and patterning device MA may be present within a vacuum chamber V where an in-vacuum robot IVR can be used to move a patterning device such as a mask in and out of the vacuum chamber. Alternatively, if the support structure MT and patterning device MA are outside the vacuum chamber, an out-of-vacuum robot similar to the in-vacuum robot IVR can be used for various transport operations. In some examples, both the in-vacuum robot and the out-of-vacuum robot need to be calibrated for smooth transfer of a payload (e.g. a mask) to the fixed motion mount of the transfer station.

[0048]

[0056] In some aspects, lithographic apparatus 100 and 100' can be used in at least one of the following modes: 1. In step mode, the support structure MT and substrate table WT are kept essentially stationary while an entire pattern imparted to the radiation beam B is projected onto a target portion C in one go (e.g. a single static exposure), and the substrate table WT is then shifted in the X and / or Y direction so that a different target portion C can be exposed. 2. In scan mode, the support structure MT and the substrate table WT are scanned synchronously (e.g. a single dynamic exposure) while a pattern imparted to the radiation beam B is projected onto a target portion C. The velocity and direction of the substrate table WT relative to the support structure MT (e.g. a mask table) may be determined by the (de-)magnification and image reversal characteristics of the projection system PS. 3. In another mode, the support structure MT is kept substantially stationary holding the programmable patterning device MA and the substrate table WT is moved or scanned while a pattern imparted to the radiation beam B is projected onto a target portion C. A pulsed radiation source SO may be used and the programmable patterning device is updated as required after each movement of the substrate table WT or between successive radiation pulses during a scan. This mode of operation can readily be applied to maskless lithography employing a programmable patterning device MA, such as a programmable mirror array.

[0049]

[0057] In some embodiments, lithographic apparatus 100 and 100' may employ combinations and / or variations of the above described modes of use or entirely different modes of use.

[0050]

[0058] 1A, lithographic apparatus 100 may include an EUV radiation source configured to generate an EUV radiation beam B for EUV lithography. In general, the EUV radiation source may be configured in a radiation source SO, and a corresponding illumination system IL may be configured to condition the EUV radiation beam B of the EUV radiation source.

[0051]

[0059] Figure 2 shows lithographic apparatus 100 in more detail, including a radiation source SO (e.g. a source collector apparatus), an illumination system IL, and a projection system PS. As shown in Figure 2, lithographic apparatus 100 is shown from a perspective (e.g. a side view) perpendicular to the XZ plane (e.g. the X axis points to the right and the Z axis points upwards).

[0052]

[0060] The radiation source SO is constructed and arranged to maintain a vacuum environment within the enclosed structure 220. The radiation source SO includes a source chamber 211 and a collector chamber 212 and is configured to generate and transmit EUV radiation. The EUV radiation may be generated by a gas or vapor, for example, xenon (Xe) gas, lithium (Li) vapor, or tin (Sn) vapor, from which an EUV radiation-emitting plasma 210 is generated to emit radiation in the EUV region of the electromagnetic spectrum. The at least partially ionized EUV radiation-emitting plasma 210 may be generated by, for example, an electric discharge or a laser beam. For efficient radiation generation, a partial pressure of, for example, about 10.0 Pascals (Pa) of Xe gas, Li vapor, Sn vapor, or any other suitable gas or vapor may be used. In some embodiments, a plasma of excited tin is provided to generate EUV radiation.

[0053]

[0061] Radiation emitted by the EUV radiation emitting plasma 210 passes from the source chamber 211 into the collector chamber 212 via an optional gas barrier or contaminant trap 230 (e.g., sometimes also referred to as a contaminant barrier or foil trap), which is positioned at or after the opening of the source chamber 211. The contaminant trap 230 may include a channel structure. The contaminant trap 230 may also include a gas barrier or a combination of a gas barrier and a channel structure. The contaminant trap 230 as further illustrated herein includes at least a channel structure.

[0054]

[0062] The collector chamber 212 may include a radiation collector CO (e.g. a condenser or collector system), which may be a so-called grazing incidence collector. The radiation collector CO has an upstream radiation collector surface 251 and a downstream radiation collector surface 252. Radiation traversing the radiation collector CO may be reflected by a grating spectral filter 240 and focused into a virtual source point INTF. The virtual source point INTF is commonly referred to as an intermediate focus, and the source collector arrangement is arranged such that the virtual source point INTF is located at or near the opening 219 of the closure structure 220. The virtual source point INTF is an image of the EUV radiation emitting plasma 210. The grating spectral filter 240 may be used to suppress infrared (IR) radiation.

[0055]

[0063] The radiation subsequently traverses the illumination system IL, which may include a faceted field mirror device 222 and a faceted pupil mirror device 224 arranged to provide a desired angular distribution of the radiation beam 221 at the patterning device MA and a desired uniformity of the radiation intensity at the patterning device MA. Upon reflection of the radiation beam 221 off the patterning device MA, which is held by the support structure MT, a patterned beam 226 is formed which is imaged by the projection system PS via reflective elements 228, 229 onto a substrate W held by a wafer stage or substrate table WT.

[0056]

[0064] There may generally be more elements in the illumination system IL and projection system PS than are shown. Optionally, a grating spectral filter 240 may be present depending on the type of lithographic apparatus. Additionally, there may be more mirrors than are shown in Figure 2. For example, there may be 1-6 more reflective elements in the projection system PS than are shown in Figure 2.

[0057]

[0065] As shown in Figure 2, radiation collector CO is depicted as a nested collector with grazing incidence reflectors 253, 254 and 255, just as an example of a collector (or collector mirror). Grazing incidence reflectors 253, 254 and 255 are arranged axisymmetrically about optical axis O, and this type of radiation collector CO is preferably used in combination with a discharge produced plasma (DPP) source.

[0058] Exemplary Lithography Cell

[0066] Figure 3 illustrates a lithography cell, sometimes referred to as a lithocell or cluster, 300. As shown in Figure 3, the lithography cell 300 is shown from a perspective (e.g., a top view) perpendicular to the XY plane (e.g., the X axis points to the right and the Y axis points up).

[0059]

[0067] The lithographic apparatus 100 or 100' may form part of a lithographic cell 300. The lithographic cell 300 may include one or more devices for performing pre-exposure and post-exposure processes on a substrate. For example, these devices may include a spin coater SC for depositing a resist layer, a developer DE for developing the exposed resist, a chill plate CH, and a bake plate BK. A substrate handler RO (e.g. a robot) picks up substrates from input / output ports I / O1 and I / O2, moves them between the various process devices, and transports them to a loading bay LB of the lithographic apparatus 100 or 100'. These devices, often collectively referred to as a track, are under the control of a track control unit TCU, which is itself controlled by a supervisory control system SCS, which also controls the lithographic apparatus via a lithographic control unit LACU. Thus, the various devices can be operated to maximize throughput and processing efficiency.

[0060] Exemplary Radiation Sources

[0068] One example of a radiation source SO for a reflective lithographic apparatus (such as lithographic apparatus 100 of FIG. 1A) is shown in Figure 4. As shown in Figure 4, the radiation source SO is shown from a perspective perpendicular to the XY plane (e.g. a top view).

[0061]

[0069] The radiation source SO shown in FIG. 4 is of a type sometimes referred to as a laser-produced plasma (LPP) source. A laser system 401, which may include, for example, a carbon dioxide (CO2) laser, is arranged to impart energy via one or more laser beams 402 to a fuel target 403', such as one or more individual tin (Sn) droplets provided from a fuel target generator 403 (e.g., a fuel emitter, a droplet generator assembly (DGA)). According to some embodiments, the laser system 401 may be a pulsed continuous wave or quasi-continuous wave laser or may operate like a pulsed continuous wave or quasi-continuous wave laser. The trajectory of the fuel target 403' (e.g., droplets) emitted from the fuel target generator 403 may be parallel to the X-axis. According to some embodiments, the one or more laser beams 402 propagate in a direction parallel to a Y-axis perpendicular to the X-axis. The Z-axis is perpendicular to both the X-axis and the Y-axis and extends generally into (or towards) the page, although other configurations are used in other embodiments. In some embodiments, the laser beam 402 can propagate in a direction other than parallel to the Y-axis (eg, in a direction other than perpendicular to the X-axis direction of the trajectory of the fuel target 403').

[0062]

[0070] In some embodiments, the one or more laser beams 402 may include a pre-pulsed laser beam and a main pulsed laser beam. In such embodiments, the laser system 401 may be configured to irradiate each of the fuel targets 403' with a pre-pulsed laser beam to generate the modified fuel targets. The laser system 401 may further be configured to irradiate each of the modified fuel targets with a main pulsed laser beam to generate a plasma 407.

[0063]

[0071] Although the following description refers to tin, any suitable target material may be used. The target material may be, for example, in liquid form and may be, for example, a metal or alloy. The fuel target generator 403 may include a nozzle configured to direct tin, for example, in the form of fuel targets 403' (e.g., individual droplets) along a trajectory toward the plasma formation region 404. Throughout the remainder of the description, references to "fuel," "fuel target," or "fuel droplets" should be understood to refer to the target material (e.g., droplets) emitted by the fuel target generator 403. The fuel target generator 403 may include a fuel emitter. One or more laser beams 402 are incident on the target material (e.g., tin) in the plasma formation region 404. Deposition of laser energy into the target material generates a plasma 407 in the plasma formation region 404. Radiation, including EUV radiation, is emitted from the plasma 407 during de-excitation and recombination of the ions and electrons of the plasma.

[0064]

[0072] The EUV radiation is collected and focused by radiation collector 405 (e.g., radiation collector CO). In some embodiments, radiation collector 405 may include a near normal incidence radiation collector (which may be more generally referred to as a normal incidence radiation collector). Radiation collector 405 may be a multi-layer structure arranged to reflect EUV radiation (e.g., EUV radiation having a desired wavelength, such as about 13.5 nm). According to some embodiments, radiation collector 405 may have an elliptical configuration with two foci. As discussed herein, the first focus may be at the plasma formation region 404 and the second focus may be at an intermediate focus 406.

[0065]

[0073] In some embodiments, the laser system 401 may be located relatively far away from the radiation source SO. In such cases, one or more laser beams 402 may pass from the laser system 401 to the radiation source SO using a beam delivery system (not shown) including, for example, appropriate directing mirrors and / or beam expanders and / or other optics. The laser system 401 and the radiation source SO may collectively be considered a radiation system.

[0066]

[0074] Radiation reflected from the radiation collector 405 forms a radiation beam B. The radiation beam B is focused to a point (e.g. intermediate focus 406) to form an image of the plasma formation region 404, which acts as a virtual radiation source for the illumination system IL. The point at which the radiation beam B is focused may be referred to as an intermediate focus (IF) (e.g. intermediate focus 406). The radiation source SO is positioned such that the intermediate focus 406 is located at or near an aperture 408 in an enclosure structure 409 of the radiation source SO.

[0067]

[0075] A radiation beam B passes from a radiation source SO into an illumination system IL. The illumination system IL is configured to condition the radiation beam B. The radiation beam B travels from the illumination system IL and is incident on a patterning device MA held by a support structure MT. The patterning device MA reflects and patterns the radiation beam B. After reflecting from the patterning device MA, the patterned radiation beam B enters a projection system PS. The projection system includes a number of mirrors configured to project the radiation beam B onto a substrate W held by a substrate table WT. The projection system PS may apply a demagnification factor to the radiation beam to form an image having smaller features than corresponding features on the patterning device MA. For example a demagnification factor of 4 may be applied. Although the projection system PS is shown in Figure 2 as having two mirrors, the projection system may include any number of mirrors (for example six mirrors).

[0068]

[0076] The source SO may include components not shown in Figure 4. For example, the source SO may be provided with a spectral filter that is substantially transparent to EUV radiation but substantially blocks other radiation wavelengths, such as infrared radiation.

[0069]

[0077] The radiation source SO (or radiation system) may further include a fuel target imaging system for obtaining an image of the fuel target (e.g. droplets) in the plasma formation region 404, more specifically for obtaining a shadow image of the fuel target. The fuel target imaging system is capable of detecting light diffracted from the edge of the fuel target. References in the following description to an image of the fuel target should be understood to also refer to a shadow image of the fuel target or a diffraction pattern produced by the fuel target.

[0070]

[0078] The fuel target imaging system may include a photodetector such as a CCD array or a CMOS sensor, although it will be appreciated that any imaging device suitable for obtaining an image of the fuel target may be used. It will be appreciated that the fuel target imaging system may include optical components such as one or more lenses in addition to the photodetector. For example, the fuel target imaging system may include a camera 410, such as a combination of a light sensor or light detector and one or more lenses. The optical components may be selected such that the light sensor or camera 410 obtains a near-field image and / or a far-field image. The camera 410 may be located in the radiation source SO at any suitable location where the camera has a line of sight to the plasma formation region 404 and one or more markers (not shown in FIG. 4 ) provided on the radiation collector 405. However, in some aspects, it may be desirable to position the camera 410 away from the propagation path of the one or more laser beams 402 and the trajectory of the fuel target emitted from the fuel target generator 403 to avoid damaging the camera 410. According to some aspects, the camera 410 is configured to provide an image of the fuel target to the controller 411 via a connection 412. Although connection 412 is shown as a wired connection, it will be understood that connection 412 (as well as other connections mentioned herein) may be implemented as a wired connection, a wireless connection, or a combination thereof.

[0071]

[0079] 4, the radiation source SO may include a fuel target generator 403 configured to generate and emit fuel targets 403′ (e.g. individual tin droplets) towards the plasma formation region 404. The radiation source SO may further include a laser system 401 configured to irradiate the one or more fuel targets 403′ with one or more laser beams 402 to generate a plasma 407 in the plasma formation region 404. The radiation source SO may further include a radiation collector 405 (e.g. radiation collector CO) configured to collect radiation emitted by the plasma 407.

[0072] Exemplary Thermally Actuated Cooling System

[0080] In some aspects, the lithographic apparatus 100 or any of the various components of the lithographic apparatus 100, including the radiation source SO, may include a thermally actuated cooling system, which is described further below.

[0073]

[0081] 5A and 5B are schematic diagrams of a thermally actuated cooling system 500 according to some embodiments of the present disclosure.

[0074]

[0082] 5A, the thermally actuated cooling system 500 can include a cooling member 502. The cooling member 502 can include, for example, a contact plate 504, fins 506 extending from the contact plate 504 in a first direction (e.g., along a positive Z-axis), and protrusions 508 extending from the contact plate 504 in a second direction (e.g., a direction substantially opposite to the first direction, such as along a negative Z-axis) and configured to couple the contact plate 504 to a portion 512 of an EUV radiation source (e.g., the radiation source SO shown in FIG. 4). The protrusions 508 can be of various suitable shapes and dimensions that correspond to a receptacle 514. The portion 512 can include, for example, a fuel target generator 403 (e.g., a DGA), any other suitable portion, component, or structure, or any portion thereof.

[0075]

[0083] In some aspects, the fins 506 may include rods. According to other aspects, the fins 506 may take other shapes, such as curved or bent, and they may include various aspect ratios and sizes and may be spaced apart from one another at various distances. Various numbers of fins in various arrangements may extend from the contact plate 504. In some aspects, the projections 508 may include threaded rods or posts. In some aspects, the projections 508 may be further configured to be partially surrounded by the annular member 516 and disposed in a receptacle 514 in the portion 512. In some aspects, the receptacle 514 may include a threaded hole. In some aspects, the receptacle 514 may be threaded to engage the projections 508. The receptacle 514 may have various depths and diameters corresponding to the projections 508. In some aspects, the annular member 516 may include a stainless steel insert (e.g., an N60 insert). In some embodiments, the portion 512 can further include a counterbore 518 having a precisely controlled depth 520. The counterbore 518 can limit contact with the annular membrane 516 between the cooling member 502 and the portion 512 when the contact plate 504 moves away from the portion 512, as shown and described in FIG.

[0076]

[0084] In some embodiments, the contact plate 504 can have a first CTE that is greater than the second CTE of the portion 512. For example, the contact plate 504 can include aluminum and have a thermal conductivity of about 22.0-24.0×10 at about 25° C. -6 K -1 and the portion 512 may include molybdenum and have a first CTE of about 4.0-6.0×10 at about 25° C. -6 K -1 The second CTE of the portion 512 may be approximately 75% to 85% lower than the first CTE of the contact plate 504. According to other embodiments, the contact plate 504 and the portion 512 may be formed of a variety of other materials, and a variety of other suitable CTEs and relative CTEs may be used.

[0077]

[0085] In some embodiments, the protrusion 508 can be configured to be in a physical strain relationship with the portion 512 .

[0078]

[0086] In some aspects, portion 512 can include heating element 522. Heating element 522 can be a variety of cartridge heaters, ceramic heaters, or the like. In some aspects, portion 512 can include additional heating elements. In some aspects, heating element 522 can be operated independently from the EUV radiation source. For example, heating element 522 can be turned on before EUV production begins and can remain on until after EUV production ends. Heating element 522 can heat portion 512 and protrusion 508.

[0079]

[0087] In some embodiments, the controller can activate the heating element 522. In some aspects, the controller 411 can be used to activate the heating element 522. In some aspects, a separate controller (not shown) can be coupled to the heating element 522. The controller can control a switch configured to turn the heating element 522 on or off. The controller can be configured to control the heating element 522 based on an operating status of the radiation source SO. For example, the controller can turn on the heating element 522 when the radiation source SO is turned on or before the radiation source is turned on (e.g., based on a preset schedule). The controller can turn off the heating element 522 when the radiation source SO is turned off or after a preset period of time has elapsed since the radiation source was turned off.

[0080]

[0088] In some embodiments, a thermocouple 524 (or other temperature measuring device) can be coupled to the heating element 522. In some aspects, the portion 512 can include a thermocouple 524. In some aspects, the thermocouple 524 can be coupled to a controller. The thermocouple 524 can be used in a control loop with the heating element 522 to maintain a target temperature. In some embodiments, the controller can compare the temperature received from the thermocouple 524 to the target temperature. The controller can turn the heating element 522 on or off based on the comparison. The location of the heating element 522 in FIG. 5A is for illustration only. The heating element and thermocouple 524 can be positioned at other locations within the portion 512.

[0081]

[0089] Portion 512 may operate at a high temperature and therefore may be heated by a variety of other means.

[0082]

[0090] 5B, when the portion 512 is heated, such as when exposed to heat from the heating element 522, the first surface 503 of the contact plate 504 is configured to move away from the second surface 513 of the portion 512 (e.g., to stop additional cooling of the portion 512 by the fins 506 during EUV radiation generating operations). In another example, as shown in FIG. 5A, when the portion 512 is not exposed to heat from the heating element 522 (e.g., when the heating element is turned off), the first surface 503 of the contact plate 504 is configured to contact the second surface 513 of the portion 512.

[0083]

[0091] In one exemplary and non-limiting exemplary embodiment, the portion 512 can be a molybdenum portion that is a component of an EUV radiation source (e.g., radiation source SO shown in FIG. 4) and operates at high temperature. In some aspects, the cooling member 502 can be an aluminum portion having a protrusion 508 (e.g., an aluminum threaded post) and can be joined to the portion 512 using a torque, where the applied torque determines the strain in the protrusion 508. The cooling member 502 and the portion 512 can be assembled at room temperature. As the assembly heats up, the molybdenum of the portion 512 and the aluminum of the cooling member 502 can expand at different rates (e.g., the CTE of molybdenum is about 5.2 ppm / K and the CTE of aluminum is about 23.1 ppm / K). The aluminum protrusion 508 expands faster than the molybdenum portion 512, and the strain in the protrusion 508 can relax at a rate of about 17.9 ppm / K. When the strain is substantially completely relieved, the contact plate 504 is lifted off the portion 512 and conductive heat transfer to the fins 506 is limited by the annular member 516 (e.g., an N60 stainless steel insert). Upon cooling, the protrusions 508 contract faster than the portion 512, eventually forcing the contact plate 504 back into contact with the portion 512, thereby cooling the portion 512. The temperature at which the contact plate 504 contacts the portion 512 can be adjusted by varying the thread diameter used, the precisely controlled depth 520 of the counterbore 518, the torque applied during assembly, and the materials used.

[0084]

[0092] In some embodiments, without the thermally actuated cooling system 500 (and without permanent fins), the heat transferred from the portion 512 can be determined according to Equation 1 below.

number

number

[0085]

[0093] In some embodiments, with the addition of thermally actuated cooling system 500 (eg, thermally actuated fins), the heat transferred may instead be determined according to Equation 2 below.

number

[0086]

[0094] FIG. 6 is a graphical illustration of a conceptual cooling profile resulting from adding the thermally actuated cooling system 500 shown in FIG. 5 to a portion of a lithographic apparatus such as a DGA, according to some embodiments of the present disclosure. As shown in FIG. 6, an experimental temperature measurement signal 602 represents an experimental cooling profile of a DGA that took about 2 hours to cool from an operating temperature (e.g., above about 250° C.) to a touch-safe temperature (e.g., below about 50° C.). As further shown in FIG. 6, a conceptual temperature measurement signal 604 represents a conceptual cooling profile of a DGA with the addition of the thermally actuated cooling system 500 shown in FIG. 5 that takes only about 1 hour to cool from an operating temperature to a touch-safe temperature. As further shown in FIG. 6, when a contact plate 504 (e.g., aluminum) contacts a portion 512 (e.g., molybdenum), the cooling rate of the experimental temperature measurement signal 602 and the cooling rate of the conceptual temperature measurement signal 604 are approximately the same until a point 606 (e.g., about 250° C.). At point 606, the cooling rate of the conceptual temperature measurement signal 604 increases dramatically, substantially improving the cooling time of the DGA.

[0087] Exemplary Process for Manufacturing a Device

[0095] 7 is a method 700 for manufacturing a device according to some embodiments or portions thereof of the present disclosure. The operations described with reference to method 700 may be performed by or in accordance with any of the systems, devices, components, techniques, or combinations thereof described herein, such as those described with reference to FIGS. 1-6 above and FIG. 8 below.

[0088]

[0096] At operation 702, the method may include providing a cooling member (e.g., cooling member 502). In some aspects, the cooling member may include a contact plate (e.g., contact plate 504), fins (e.g., fins 506) extending from the contact plate in a first direction, and protrusions (e.g., protrusions 508) extending from the contact plate in a second direction (e.g., a direction substantially opposite to the first direction). In some aspects, the cooling member may be provided using any suitable optical, electrical, mechanical, or other method, and may include providing the cooling member according to any aspect or combination of aspects described with reference to FIGS. 1-6 above and FIG. 8 below.

[0089]

[0097] In operation 704, the method may include attaching a protrusion to a portion (e.g., portion 512) of an EUV radiation source (e.g., radiation source SO). The contact plate may include a first CTE that is greater than a second CTE of the portion. For example, the contact plate may include aluminum and the portion may include molybdenum, and the first CTE of the aluminum may be greater than the second CTE of the molybdenum. In some embodiments, when the protrusion is attached to the portion, the protrusion may be in a physical strain relationship with the portion such that (i) when the portion is exposed to heat (e.g., when heating element 522 of portion 512 is turned on or operating at an elevated temperature), the first surface of the contact plate (e.g., first surface 503) is configured to move away from the second surface of the portion (e.g., second surface 513) (e.g., as shown in FIG. 5B ), and (ii) when the portion is not exposed to heat, the first surface of the contact plate is configured to contact the second surface of the portion (e.g., as shown in FIG. 5A ). In some embodiments, attachment of the projection to the portion can be accomplished using suitable optical, electrical, mechanical, or other methods, and includes attaching the projection to the portion according to any embodiment or combination of embodiments described with reference to Figures 1-6 above and Figure 8 below.

[0090] Exemplary Computing System

[0098] Aspects of the present disclosure may be implemented in hardware, firmware, software, or any combination thereof. For example, the design of one or more materials of the contact plate 504 and the portion 512, the CTE, the relative CTE, the dimensions of the receptacle 514, the precisely controlled depth 512 may be implemented using hardware, firmware, software, or any combination thereof. Aspects of the present disclosure may be implemented as instructions stored on a machine-readable medium that may be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium may include a read-only memory (ROM), a random-access memory (RAM), a magnetic disk storage medium, an optical storage medium, a flash memory device, an electrical, optical, acoustic, or other form of propagated signal (e.g., a carrier wave, an infrared signal, a digital signal, etc.), and the like. Additionally, firmware, software, routines, instructions, and combinations thereof may be described herein as performing certain operations. However, it should be understood that such description is merely for convenience, and that such operations would in fact result from a computing device, processor, controller, or other device executing firmware, software, routines, instructions, or combinations thereof, and in so doing causing actuators or other devices (e.g., servo motors, robotic devices) to interact with the physical world.

[0091]

[0099] Various aspects may be implemented using one or more computing systems, such as, for example, the computing system 800 shown in FIG. 8. The computing system 800 may be a special purpose computer capable of performing the functions described herein, such as the laser system 401 described with reference to FIG. 4, the thermally actuated cooling system 500 described with reference to FIG. 5, any other suitable system, subsystem or component, or any combination thereof. The computing system 800 may include one or more processors (also referred to as central processing units or CPUs), such as processor 804. The processor 804 is connected to a communication infrastructure 806 (e.g., a bus). The computing system 800 may include one or more user input / output devices 803, such as a monitor, keyboard, pointing device, etc., that communicate with the communication infrastructure 806 via one or more user input / output interfaces 802. The computing system 800 may include a main memory 808 (e.g., one or more primary storage devices), such as a random access memory (RAM). The main memory 808 may include one or more levels of cache. The main memory 808 stores control logic (e.g., computer software) and / or data therein.

[0092]

[0100] Computing system 800 may also include secondary memory 810 (e.g., one or more secondary storage devices). The secondary memory 810 may include, for example, a hard disk drive 812 and / or a removable storage drive 814. The removable storage drive 814 may be a floppy disk drive, a magnetic tape drive, a compact disk drive, an optical storage device, a tape backup device, and / or any other storage device / drive.

[0093]

[0101] The removable storage drive 814 can interact with a removable storage unit 818. The removable storage unit 818 includes a computer usable or readable storage device that stores computer software (control logic) and / or data. The removable storage unit 818 may be a floppy disk, magnetic tape, compact disk, DVD, optical storage disk, and / or any other computer data storage device. The removable storage drive 814 reads from and / or writes to the removable storage unit 818.

[0094]

[0102] According to some aspects, secondary memory 810 may include other means, devices, or other techniques for allowing computer programs and / or other instructions and / or data to be accessed by computing system 800. Such means, devices, or techniques may include, for example, removable storage unit 822 and interface 820. Examples of removable storage unit 822 and interface 820 may include a program cartridge and cartridge interface (such as those found in video game devices), removable memory chips (such as EPROM or PROM) and associated sockets, memory sticks and USB ports, memory cards and associated memory card slots, and / or any other removable storage unit and associated interface.

[0095]

[0103] Computing system 800 may further include a communications interface 824 (e.g., one or more network interfaces). Communications interface 824 enables computing system 800 to communicate and interact with any combination of remote devices, remote networks, remote entities, etc. (individually and collectively referred to as remote devices 828). For example, communications interface 824 may enable communications between computing system 800 and remote devices 828 over communications paths 826, which may be wired and / or wireless, and may include any combination of a LAN, a WAN, the Internet, etc. Control logic, data, or both may be transmitted to and from computing system 800 over communications paths 826.

[0096]

[0104] The operations of the aforementioned aspects of the present disclosure may be implemented in a variety of configurations and architectures. Thus, some or all of the operations of the aforementioned aspects may be performed in hardware, software, or both. In some aspects, a tangible, non-transitory apparatus or article of manufacture includes a tangible, non-transitory computer usable or readable medium having stored thereon control logic (software), also referred to herein as a computer program product or program storage device. This includes, but is not limited to, a computing system 800, a main memory 808, a secondary memory 810, and removable storage units 818 and 822, as well as tangible articles of manufacture embodying any combination of the above. Such control logic, when executed by one or more data processing devices (such as computing system 800), causes such data processing devices to perform the operations described herein.

[0097]

[0105] Based on the teachings contained herein, it will be apparent to one of ordinary skill in the art how to implement and use aspects of the present disclosure using data processing devices, computer systems and / or computer architectures other than those shown in Figure 8. In particular, aspects of the present disclosure may operate with software, hardware, and / or operating system implementations other than those described herein.

[0098]

[0106] Although specific reference is made herein to the use of lithographic apparatus in the manufacture of ICs, it should be understood that the lithographic apparatus described herein may have other applications, such as the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, LCDs, thin film magnetic heads, and the like. In such other applications, those skilled in the art will appreciate that any term "wafer" or "die" used herein may be considered synonymous with the more general terms "substrate" or "target portion", respectively. Substrates referred to herein may be processed, before or after exposure, for example, in a track unit (a tool that applies a layer of resist to a substrate and develops the exposed resist), a metrology unit, and / or an inspection unit. Where applicable, the disclosure herein may be applied to such and other substrate processing tools. Furthermore, a substrate may be processed multiple times, for example to create a multi-layer IC, and thus the term substrate as used herein may refer to a substrate that already includes multiple processing layers.

[0099]

[0107] It is to be understood that the terms or phrases used herein are for purposes of description and not of limitation, as such terms or phrases would be interpreted by one of ordinary skill in the art in light of the teachings herein.

[0100]

[0108] The term "substrate" as used herein refers to a material onto which a layer of material is applied. In some aspects, the substrate itself may be patterned, or the material applied onto the substrate may also be patterned or may remain unpatterned.

[0101]

[0109] The examples disclosed herein are illustrative and not limiting of embodiments of the disclosure. Other suitable modifications and adaptations of the variety of conditions and parameters normally encountered in the art, which will be apparent to those skilled in the art, are within the spirit and scope of the disclosure.

[0102]

[0110] While specific aspects of the disclosure have been described above, it will be understood that these aspects may be practiced otherwise than as described. These descriptions are not intended to limit the embodiments of the disclosure.

[0103]

[0111] It should be understood that the Detailed Description section, and not the Background, Overview, and Abstract sections, are intended to be used to interpret the claims. The Overview and Abstract sections may describe one or more (but not all) example embodiments as contemplated by the inventors, and thus are not intended to limit the present embodiments and the appended claims.

[0104]

[0112] Some aspects of the present disclosure have been described above using functional building blocks that show the implementation of specific functions and their relationships. The boundaries of these functional building blocks are arbitrarily defined herein for the convenience of description. Other boundaries may be defined as long as the specific functions and their relationships are appropriately implemented.

[0105]

[0113] The above description of specific embodiments of the present disclosure will fully clarify the general nature of the embodiments so that others, by applying knowledge within the skill of the art, can readily modify and / or adapt such specific embodiments for various applications without undue experimentation and without departing from the general concept of the present disclosure. Such adaptations and modifications are therefore intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein.

[0106]

[0114] Other aspects of the invention are set forth in the following numbered clauses. 1. A system comprising: The cooling member includes: A contact plate; a fin extending in a first direction from the contact plate; a protrusion extending in a second direction from the contact plate and configured to couple the contact plate to a portion of an extreme ultraviolet (EUV) radiation source; Equipped with The contact plate includes a first coefficient of thermal expansion (CTE) greater than a second CTE of the portion. 2. A portion of the EUV radiation source includes a heating element, and the protrusion is configured to be in a physical strain relationship with the portion, whereby a first surface of the contact plate configured to move away from a second surface of the portion when the portion is heated by the heating element; 13. The system of claim 1, wherein the first surface of the contact plate is configured to contact the second surface of the portion when the portion is not exposed to heat. 3. The system of claim 1, wherein the fin comprises a rod. 4. The system of claim 1, wherein the protrusion comprises a threaded rod. 5. The system of claim 1, wherein the contact plate comprises aluminum and a portion comprises molybdenum. 6. The system of claim 1, wherein the protrusion is further configured to be partially surrounded by the annular member and disposed within a portion of the receptacle. 7. The system of claim 6, wherein the receptacle includes a threaded hole and the projection includes a threaded rod. 8. The system of claim 6, wherein the annular member comprises a stainless steel insert, the contact plate comprises aluminum, and a portion comprises molybdenum. 9. An apparatus comprising: A contact plate; a protrusion extending from the contact plate and configured to couple the contact plate to a portion of the extreme ultraviolet (EUV) radiation source, the protrusion configured to be in a physical strain relationship with the portion, whereby a first surface of the contact plate configured to move away from a second surface of the portion when the portion is heated; The apparatus, wherein a first surface of the contact plate is configured to contact a second surface of the portion when the portion is not exposed to heat. 10. The apparatus of clause 9, further comprising fins extending from the contact plate in a first direction, the protrusions extending in a second, opposite direction. 11. The apparatus of claim 10, wherein the fin comprises a rod, a portion of which comprises a heating element. 12. The apparatus of claim 9, wherein the protrusion includes a threaded rod and is configured to be received within a receptacle in the portion. 13. The apparatus of claim 9, wherein the contact plate comprises aluminum and a portion comprises molybdenum. 14. The apparatus of claim 9, wherein the projection is further configured to be partially surrounded by the annular member and disposed within a portion of the receptacle. 15. The apparatus of claim 14, wherein the contact plate comprises aluminum, a portion comprises molybdenum, and the annular member comprises stainless steel. 16. The apparatus of claim 12, wherein the receptacle includes a threaded hole. 17. A method comprising: providing a cooling member, the cooling member comprising: A contact plate; a fin extending in a first direction from the contact plate; a protrusion extending in a second direction from the contact plate; Providing and providing Attaching the protrusion to a portion of an extreme ultraviolet (EUV) radiation source; wherein the contact plate includes a first coefficient of thermal expansion (CTE) greater than a second CTE of the portion. 18. When a protrusion is attached to a part, the protrusion is in a physical strain relationship with the part, thereby a first surface of the contact plate configured to move away from a second surface of the portion when the portion is heated; 18. The method of claim 17, wherein the first surface of the contact plate is configured to contact the second surface of the portion when the portion is not exposed to heat. 19. The method of claim 18, wherein the projection is threaded, and the method further comprises attaching the projection by engaging the projection with corresponding threads of a threaded receptacle of the part, wherein distortion of the projection is relieved when the part is heated. 20. The method of claim 17, wherein the contact plate comprises aluminum and a portion comprises molybdenum. 21. Attaching a protrusion to a part Attaching an annular member to the projection, the annular member partially surrounding the projection; disposing the projection and the annular member within the receptacle of the portion; 18. The method according to claim 17, comprising:

[0107]

[0115] The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary aspects or embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims

1. 1. A system comprising: A cooling member is provided, the cooling member comprising: A contact plate; a fin extending in a first direction from the contact plate; a protrusion extending in a second direction from the contact plate and configured to couple the contact plate to a portion of an extreme ultraviolet (EUV) radiation source; Equipped with The contact plate includes a first coefficient of thermal expansion (CTE) greater than a second CTE of the portion.

2. The portion of the EUV radiation source includes a heating element, and the protrusion is configured to be in a physical strain relationship with the portion, whereby a first surface of the contact plate is configured to move away from a second surface of the portion when the portion is heated by the heating element; The system of claim 1 , wherein the first surface of the contact plate is configured to contact the second surface of the portion when the portion is not exposed to heat.

3. The system of claim 1 , wherein the fin comprises a rod.

4. The system of claim 1 , wherein the protrusion comprises a threaded rod.

5. The system of claim 1 , wherein the contact plate comprises aluminum and the portion comprises molybdenum.

6. The system of claim 1 , wherein the protrusion is further configured to be partially surrounded by an annular member and disposed within a receptacle in the portion.

7. The system of claim 6 , wherein the receptacle comprises a threaded hole and the protrusion comprises a threaded rod.

8. The system of claim 6 , wherein the annular member comprises a stainless steel insert, the contact plate comprises aluminum, and the portion comprises molybdenum.

9. An apparatus comprising: A contact plate; a protrusion extending from the contact plate and configured to couple the contact plate to a portion of an extreme ultraviolet (EUV) radiation source, the protrusion configured to be in a physical strain relationship with the portion, whereby a first surface of the contact plate is configured to move away from a second surface of the portion when the portion is heated; the first surface of the contact plate is configured to contact the second surface of the portion when the portion is not exposed to heat.

10. The apparatus of claim 9 , further comprising fins extending in a first direction from the contact plate, the protrusions extending in a second opposite direction.

11. The apparatus of claim 10 , wherein the fin comprises a rod and the portion comprises a heating element.

12. The device of claim 9 , wherein the protrusion comprises a threaded rod and is configured to be received within a receptacle in the portion.

13. 10. The apparatus of claim 9, wherein the contact plate comprises aluminum and the portion comprises molybdenum.

14. The apparatus of claim 9 , wherein the protrusion is further configured to be partially surrounded by an annular member and disposed within a receptacle in the portion.

15. 15. The apparatus of claim 14, wherein the contact plate comprises aluminum, the portion comprises molybdenum, and the annular member comprises stainless steel.

16. The apparatus of claim 12 , wherein the receptacle includes a threaded hole.

17. 1. A method comprising: A cooling member is provided, the cooling member comprising: A contact plate; a fin extending in a first direction from the contact plate; a protrusion extending in a second direction from the contact plate; Providing and providing attaching the protrusion to a portion of an extreme ultraviolet (EUV) radiation source; wherein the contact plate comprises a first coefficient of thermal expansion (CTE) greater than a second CTE of the portion.

18. When the protrusion is attached to the portion, the protrusion is in a physical strain relationship with the portion, thereby a first surface of the contact plate is configured to move away from a second surface of the portion when the portion is heated; The method of claim 17 , wherein the first surface of the contact plate is configured to contact the second surface of the portion when the portion is not exposed to heat.

19. 20. The method of claim 18, wherein the projection is threaded, the method further comprising attaching the projection by engaging it with corresponding threads of a threaded receptacle in the portion, wherein strain on the projection is relieved when the portion is heated.

20. The method of claim 17 , wherein the contact plate comprises aluminum and the portion comprises molybdenum.

21. Attaching the protrusion to the portion includes: attaching an annular member to the projection, the annular member partially surrounding the projection; disposing said projection and said annular member within a receptacle in said portion; 20. The method of claim 17, comprising:

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