Substrate support and lithographic apparatus

Abstract

A substrate support configured to support a substrate within a lithographic apparatus, the substrate support comprising: a first circumferential wall; a first opening that is radially outside the first circumferential wall and is configured to supply and / or extract gas; a second circumferential wall that is radially outside the first opening; a second opening that is in fluid communication with the ambient pressure and is radially outside the second circumferential wall; a third circumferential wall that is radially outside the second opening; a third opening that is radially outside the third circumferential wall and is configured to extract fluid; and a fourth circumferential wall that is radially outside the third opening.

Description

Technical Field

[0001] Cross-reference to related applications

[0001] This application claims the priority of European Patent Application No. 22179329.2 filed on June 15, 2022, and incorporates the entire content thereof by reference into this application.

[0002]

[0002] The present invention relates to a substrate support configured to support a substrate within a lithographic apparatus, a method of loading a substrate onto the substrate support, a lithographic apparatus including the substrate support, and a method of manufacturing a device including a method of loading a substrate onto the substrate support.

Background Art

[0003]

[0003] A lithographic apparatus is a machine constructed to apply a desired pattern onto a substrate. The lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). The lithographic apparatus can project, for example, a pattern of a patterning device (e.g., a mask) (often also referred to as a “design layout” or “design”) onto a layer of radiation-sensitive material (resist) provided on a substrate (e.g., a wafer). Known lithographic apparatuses include so-called steppers that irradiate each target portion by exposing the entire pattern at once onto the target portion, and so-called scanners that scan a pattern in a particular direction (the “scan” direction) by a radiation beam while scanning the substrate parallel or anti-parallel to this direction to irradiate each target portion.

[0004]

[0004] As semiconductor manufacturing processes have been continuously advancing, for decades, the number of functional elements such as transistors per device has been steadily increasing, while the dimensions of circuit elements have been continuously decreasing, generally following the trend known as "Moore's Law". To keep up with Moore's Law, the semiconductor industry is pursuing technologies that enable the creation of even smaller features. A lithographic apparatus may use electromagnetic radiation to project a pattern onto a substrate. The wavelength of this radiation determines the minimum size of the features patterned on the substrate. Commonly used wavelengths currently are 365 nm (i-line), 248 nm, 193 nm, and 13.5 nm.

[0005]

[0005] Further improvements in the resolution of smaller features can be achieved by providing an immersion fluid such as water, which has a relatively high refractive index, on the substrate during exposure. The effect of the immersion fluid is to enable imaging of smaller features because the exposure radiation in the fluid has a shorter wavelength than in air. The effect of the immersion fluid is also thought to increase the effective numerical aperture (NA) of the system and increase the depth of focus.

[0006]

[0006] The immersion fluid can be confined by a fluid handling structure to a local area between the projection system of the lithographic apparatus and the substrate.

Summary of the Invention

[0007]

[0007] In a semiconductor manufacturing process, a substrate is supported on a substrate support. Specifically, the substrate is supported on a plurality of bars protruding from the surface of the substrate support.

[0008]

[0008] In the semiconductor industry, due to the reduction of the stacked film layers on the substrate and the increase in the number of layers, there is an increasing trend to integrate more functions per unit surface of the substrate. As the number of layers stacked on the substrate increases, the stress generated between the film and the substrate increases, and a large warp of the substrate may occur.

[0009]

[0009] As a result, variable friction is generated between the outer peripheral ring of the bar and the lower side of the substrate, which can lead to high reproducibility of the substrate. This can be reduced by surrounding the outer peripheral ring of the bar with a fluid, i.e., an immersion fluid. However, this increases the humidity gradient and can cause drift in the flatness of the substrate support.

[0010]

[0010] It is an object of the present invention to reduce problems associated with loading a warped substrate without increasing the flatness drift of the substrate support.

[0011]

[0011] According to the present invention, there is provided a substrate support configured to support a substrate within a lithographic apparatus, the substrate support comprising a first circumferential wall, a first opening radially outside the first circumferential wall and configured to supply and / or extract gas, a second circumferential wall radially outside the first opening, a second opening in fluid communication with the ambient pressure and radially outside the second circumferential wall, a third circumferential wall radially outside the second opening, a third opening radially outside the third circumferential wall and configured to extract fluid, and a fourth circumferential wall radially outside the third opening.

[0012]

[0012] According to the present invention, there is also provided a method of loading a substrate onto a substrate support having a first circumferential wall, a second circumferential wall radially outside the first circumferential wall, a third circumferential wall radially outside the second circumferential wall, and a fourth circumferential wall radially outside the third circumferential wall, wherein there is a first region between the first circumferential wall and the second circumferential wall, a second region between the second circumferential wall and the third circumferential wall, and a third region between the third circumferential wall and the fourth circumferential wall, the method comprising a substrate loading step in which gas is supplied to the first region, and a substrate clamping step in which gas is extracted from the first region and fluid is extracted from the third region.

[0013]

[0013] According to the present invention, there is also provided a lithographic apparatus comprising a substrate support.

[0014]

[0014] According to the present invention, a method of manufacturing a device including a method of loading a substrate on a substrate support is also provided.

[0015]

[0015] Further embodiments, features and advantages of the present invention, and the structure and operation of various embodiments, features and advantages of the present invention will be described in detail below with reference to the accompanying drawings.

Brief Description of the Drawings

[0016]

[0016] Some embodiments of the present invention will be described below by way of example only with reference to the accompanying schematic diagrams. The same reference numerals in these drawings indicate corresponding parts.

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11A

Figure 11B

Figure 12

[0018]

[0017] The illustrated features are not necessarily to scale and are not limited to the sizes and / or arrangements shown. The figures are to be understood as including any features that may not be essential to the invention. Further, not all features of the device are shown in each of the figures, and the figures may show only some of the relevant components for describing a particular feature.

Embodiments for Carrying Out the Invention

[0019]

[0018] In this document, the terms "radiation" and "beam" are used to encompass any kind of electromagnetic radiation including ultraviolet light (e.g., having wavelengths of 365, 248, 193, 157, or 126 nm).

[0020]

[0019] The terms "reticle", "mask", or "patterning device" used in this text may be broadly interpreted to refer to a general patterning device that can be used to impart a patterned cross-section corresponding to a pattern generated on a target portion of a substrate to an incident radiation beam. The term "light valve" may also be used in this context. Examples of other such patterning devices include programmable mirror arrays and programmable LCD arrays in addition to classical masks (transmission or reflection type, binary type, phase shift type, hybrid type, etc.).

[0021]

[0020] Figure 1 schematically depicts a lithographic apparatus. The lithographic apparatus includes an illumination system (also referred to as an illuminator) IL configured to condition a radiation beam B (e.g., UV radiation or DUV radiation), a mask support (e.g., a mask table) MT constructed to support a patterning device (e.g., a mask) MA and connected to a first positioner PM configured to accurately position the patterning device MA in accordance with certain parameters, a substrate support (e.g., a substrate table) WT constructed to hold a substrate (e.g., a resist-coated wafer) W and connected to a second positioner PW configured to accurately position the substrate support WT in accordance with certain parameters, and a projection system (e.g., a refractive projection lens system) PS configured to project a pattern imparted to the radiation beam B by the patterning device MA onto a target portion C (e.g., including one or more dies) of the substrate W.

[0022]

[0021] During operation, the illumination system IL receives the radiation beam B from a radiation source SO, e.g., via a beam delivery system BD. The illumination system IL can include various types of optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic, and / or other types of optical components, or any combination thereof, for directing, shaping, and / or controlling the radiation. The illuminator IL may be used to condition the radiation beam B such that it has a desired spatial and angular intensity distribution in the plane and in the cross-section of the patterning device MA.

[0023] As used herein, the term "projection system" PS is to be broadly construed to encompass any type of projection system, including refractive, reflective, catadioptric, anamorphic, magnetic, electromagnetic, and / or electrostatic optical systems, or any combination thereof, that is appropriate for the exposure radiation being used and / or for other factors such as the use of an immersion liquid or the use of a vacuum. It is to be understood that all terms used herein as "projection lens" are to be considered synonymous with the more general term "projection system" PS.

[0024]

[0023] The lithographic apparatus may be of a type in which at least a portion of the substrate W is covered by an immersion liquid such as water having a relatively high refractive index to fill the immersion space 11 between the projection system PS and the substrate W (also referred to as immersion lithography). Further information regarding immersion techniques is given in U.S. Patent No. 6,952,253, which is incorporated herein by reference.

[0025]

[0024] The lithographic apparatus may be of a type having two or more substrate supports WT (also referred to as "dual stage"). In such a "multi-stage" machine, the substrate supports WT can be used in parallel and / or preparatory steps for a subsequent exposure of the substrate W can be carried out on the substrate W located on one of the substrate supports WT while the other substrate W on the other substrate support WT is being used for exposing a pattern on the other substrate W.

[0026] In addition to the substrate support WT, the lithographic apparatus may comprise a measurement stage (not shown). The measurement stage is arranged to hold a sensor and / or a cleaning device. The sensor may be arranged to measure a characteristic of the projection system PS or of the radiation beam B. The measurement stage may hold a plurality of sensors. The cleaning device may be arranged to clean a part of the lithographic apparatus, for example a part of the projection system PS or a part of the system that provides the immersion liquid. The measurement stage may move under the projection system PS when the substrate support WT is away from the projection system PS.

[0027]

[0026] During operation, the radiation beam B is incident on a patterning device (e.g., a mask MA) held on the mask support MT and is patterned by a pattern (design layout) present on the patterning device MA. After passing through the mask MA, the radiation beam B passes through the projection system PS, and the projection system PS focuses the beam on the target portion C of the substrate W. Using the second positioner PW and the position measurement system IF, the substrate support WT can be accurately moved, for example, to position different target portions C at a focused and aligned position within the path of the radiation beam B. Similarly, using the first positioner PM and optionally another position sensor (not explicitly shown in Figure 1a), the patterning device MA can be accurately positioned with respect to the path of the radiation beam B. 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. In the example, the substrate alignment marks P1 and P2 occupy dedicated target portions, but the substrate alignment marks can also be placed in the space between the target portions. The substrate alignment marks P1 and P2, when arranged between the target portions C, are known as scribe line alignment marks.

[0028]

[0027] To clarify the invention, a Cartesian coordinate system is used. The Cartesian coordinate system has three axes, namely, the x-axis, the y-axis, and the z-axis. Each of the three axes is orthogonal to the other two axes. A rotation about the x-axis is called an Rx rotation. A rotation about the y-axis is called an Ry rotation. A rotation about the z-axis is called an Rz rotation. The x-axis and the y-axis define a horizontal plane, while the z-axis defines a vertical direction. The Cartesian coordinate system does not limit the invention and is used only for explanation. Instead, other coordinate systems such as a cylindrical coordinate system may be used to clarify the invention. For example, the orientation of the Cartesian coordinate system may be different such that the z-axis has a component along the horizontal plane.

[0029]

[0028] The immersion technique has been introduced into a lithography system to enable improvement in the resolution of smaller features. In an immersion lithography apparatus, a liquid layer of an immersion liquid having a relatively high refractive index is interposed in an immersion space 11 between a projection system PS of the apparatus (through which a pattern-formed beam is projected toward a substrate W) and the substrate W. The immersion liquid is under the final element of the projection system PS and covers at least a part of the substrate W. Thus, at least a part of the substrate W during exposure is immersed in the immersion liquid.

[0030]

[0029] In commercial immersion lithography, the immersion liquid is water. The water is typically high-purity distilled water such as ultrapure water (UPW) commonly used in a semiconductor manufacturing plant. In an immersion system, the UPW is frequently purified and may have to undergo additional processing steps before being supplied as the immersion liquid to the immersion space 11. For example, other liquids other than water having a high refractive index, such as hydrocarbons like fluorocarbons and / or aqueous solutions, can also be used as the immersion liquid. Furthermore, other fluids other than liquids are also envisioned for use in immersion lithography.

[0031]

[0030] In this specification, reference is made to local immersion in which the immersion liquid in use is confined in the immersion space 11 between the final element and the surface facing the final element. The facing surface is the surface of the substrate W or the surface of the support stage (or substrate support WT) on the same plane as the surface of the substrate W (note that references to the surface of the substrate W in the following text represent, in addition to or instead of, the surface of the substrate support WT unless otherwise specified, and vice versa). The fluid handling structure IH existing between the projection system PS and the substrate support WT is used to confine the immersion liquid in the immersion space 11. The immersion space 11 filled with the immersion liquid is smaller than the upper surface of the substrate W in plan view, and the immersion space 11 remains substantially stationary with respect to the projection system PS while the substrate W and the substrate support WT move below.

[0032]

[0031] Other immersion systems are also envisioned, such as non-confined immersion systems (so-called "all-wet" immersion systems) and bath-type immersion systems. In a non-confined immersion system, the immersion liquid covers more than the lower surface of the final element. The liquid outside the immersion space 11 exists as a thin liquid film. The liquid may cover the entire surface of the substrate W or the substrate W and the substrate support WT on the same plane as the substrate W. In a bath-type system, the substrate W is completely immersed in a bath of the immersion liquid.

[0033]

[0032] The fluid handling structure IH is a structure that confines the immersion liquid in the immersion space 11 by supplying the immersion liquid to the immersion space 11 and removing the immersion liquid from the immersion space 11. It includes features that are part of a fluid supply system. The configuration disclosed in PCT Patent Application Publication No. WO99 / 49504 is an initial fluid handling structure that supplies or recovers the immersion liquid from the immersion space 11 and includes pipes that operate in response to the relative movement of the stage under the projection system PS. In more recent designs, the fluid handling structure extends along at least a part of the boundary of the immersion space 11 between the final element of the projection system PS and the substrate support WT or the substrate W, and partially defines the immersion space 11.

[0034]

[0033] The fluid handling structure IH may have options of different functions. Each function can be derived from corresponding features that enable the fluid handling structure IH to realize the function. The fluid handling structure IH can be called by many different terms representing functions, such as a barrier member, a seal member, a fluid supply system, a fluid removal system, a liquid confinement structure, etc.

[0035]

[0034] The fluid handling structure IH as a barrier member is a barrier against the flow of the immersion liquid from the immersion space 11. The structure as a liquid confinement structure confines the immersion liquid in the immersion space 11. The sealing feature of the fluid handling structure IH as a seal member forms a seal for confining the immersion liquid in the immersion space 11. The sealing feature may include an additional gas flow from an opening on the surface of the seal member such as a gas knife.

[0036]

[0035] The fluid handling structure IH may supply the immersion fluid and thereby be a fluid supply system.

[0037]

[0036] The fluid handling structure IH may at least partially confine the immersion fluid and thereby be a fluid confinement system.

[0038]

[0037] The fluid handling structure IH may provide a barrier to the immersion fluid and thereby be a barrier member such as a fluid confinement structure.

[0039]

[0038] The fluid handling structure IH may generate or use a gas flow, for example, to assist in controlling the flow and / or position of the immersion fluid.

[0040]

[0039] The gas flow may form a seal for confining the immersion fluid, and the fluid handling structure IH can be called a seal member. Such a seal member may also be a fluid confinement structure.

[0041]

[0040] The immersion liquid can be used as the immersion fluid. In this case, the fluid handling structure IH may be a liquid handling system. Referring to the above description, references to features defined for the fluid in these paragraphs can be understood to include features defined for liquids.

[0042]

[0041] The lithographic apparatus has a projection system PS. During the exposure of the substrate W, the projection system PS projects a patterned beam of radiation onto the substrate W. In order to reach the substrate W, the path of the radiation beam B passes through an immersion liquid confined by a fluid handling structure IH between the projection system PS and the substrate W. The projection system PS has a lens element that contacts the immersion liquid at the end of the beam path. This lens element that contacts the immersion liquid can be referred to as the "final lens element" or "final element". The final element is at least partially surrounded by the fluid handling structure IH. The fluid handling structure IH may confine the immersion liquid below the final element and above the opposing surface.

[0043]

[0042] As shown in FIG. 1, the lithographic apparatus comprises a controller 500. The controller 500 is configured to control the substrate table WT.

[0044]

[0043] FIG. 2 schematically shows a local liquid supply system or a fluid handling system. The liquid supply system is provided with a fluid handling structure IH (or liquid confinement structure) extending along at least a part of the boundary of the space 11 between the final element of the projection system PS and the support table WT or the substrate W. The fluid handling structure IH is substantially stationary with respect to the projection system PS in the XY plane, but some relative movement can occur in the Z direction (the direction of the optical axis). In one example, a seal is formed between the fluid handling structure IH and the surface of the substrate W, which may be a non-contact seal such as a gas seal (such a system having a gas seal is disclosed in European Patent No. 1,420,298) or a liquid seal.

[0045]

[0044] The immersion liquid is at least partially confined within the space 11 between the final element of the projection system PS and the substrate W by a fluid handling structure IH. The space 11 is at least partially formed by a fluid handling structure IH positioned below the final element of the projection system PS and surrounding the final element. The immersion liquid is introduced into the space 11 within the fluid handling structure IH below the projection system PS by one of the liquid openings 13. The immersion liquid can also be removed by another one of the liquid openings 13. The immersion liquid may be introduced into the space 11 via at least two liquid openings 13. Which of the liquid openings 13 is used to supply the immersion liquid and optionally which of the liquid openings 13 is used to remove the immersion liquid may depend on the operating direction of the support table WT.

[0046]

[0045] During use, a non-contact seal such as a gas seal 16 formed by the gas formed between the bottom of the fluid handling structure IH and the surface of the substrate W can confine the immersion liquid within the space 11. The gas within the gas seal 16 is provided under pressure through the inlet 15 into the gap between the fluid handling structure IH and the substrate W. The gas is withdrawn via the outlet 14. The overpressure of the gas inlet 15, the vacuum level of the outlet 14, and the geometry of the gap are configured such that a high-speed gas flow inward is generated to confine the immersion liquid. Such a system is disclosed in U.S. Patent No. 2004 / 0207824, which is hereby incorporated by reference in its entirety. In one example, the fluid handling structure IH does not have a gas seal 16.

[0047]

[0046] FIG. 3 is a side cross-sectional view showing a further liquid supply system or fluid handling system. The configuration shown in FIG. 3 and described below can be applied to the lithographic apparatus shown in FIG. 1 above. The liquid supply system is provided with a fluid handling structure IH (or liquid confinement structure) extending along at least a part of the boundary of the space 11 between the final element of the projection system PS and the support table WT or the substrate W.

[0048]

[0047] The fluid handling structure IH confines the immersion liquid at least partially within the space 11 between the final element of the projection system PS and the substrate W. The space 11 is at least partially formed by a fluid handling structure IH positioned below and surrounding the final element of the projection system PS. In one example, the fluid handling structure IH includes a body member 53 and a porous member 33. The porous member 33 is plate-shaped and has a plurality of holes (i.e., openings or pores). The porous member 33 is a mesh plate, and a large number of small holes 84 are formed in a mesh pattern. Such a system is disclosed in U.S. Patent No. 2010 / 0045949A1, which is hereby incorporated by reference in its entirety.

[0049]

[0048] The body member 53 includes a supply port 72 capable of supplying the immersion liquid to the space 11 and a recovery port 73 capable of recovering the immersion liquid from the space 11. The supply port 72 is connected to a liquid supply device 75 via a passage 74. The liquid supply device 75 can supply the immersion liquid to the supply port 72 via the corresponding passage 74. The recovery port 73 can recover the immersion liquid from the space 11. The recovery port 73 is connected to a liquid recovery device 80 via a passage 79. The liquid recovery device 80 recovers the immersion liquid recovered via the recovery port 73 through the passage 29. The porous member 33 is disposed at the recovery port 73. By performing a liquid supply operation using the supply port 72 and a liquid recovery operation using the porous member 33, the space 11 is formed on one side between the projection system PS and the fluid handling structure IH and on the other side between the substrate W.

[0050]

[0049] Although not according to the present invention, FIG. 4 shows a part of a lithographic apparatus useful for explaining the features of the present invention. The configuration shown in FIG. 4 and described below can be applied to the above-described lithographic apparatus shown in FIG. 1. FIG. 4 is a cross-section of the substrate support 20 and the substrate W. In one embodiment, the substrate support 20 comprises one or more adjustment channels 61 of a thermal conditioner 60 described in more detail below. There is a gap 5 between the edge of the substrate W and the edge of the substrate support 20. When the edge of the substrate W is imaged or at another time (as described above) when the substrate W first moves under the projection system PS, for example, the immersion space 11 filled with liquid by the fluid confinement structure IH (for example) at least partially passes over the gap 5 between the edge of the substrate W and the edge of the substrate support 20. Thereby, the liquid from the immersion space 11 can enter the gap 5.

[0051]

[0050] The substrate W is held by a support 21 (for example, a pimple or a bar table) including one or more burls 41 (i.e., protrusions from the surface). The support 21 is an example of an object holder. Another example of an object holder is a mask holder. The negative pressure applied between the substrate W and the substrate support 20 ensures that the substrate W is firmly held in place. However, when the immersion liquid enters between the substrate W and the support 21, it may cause problems, especially when unloading the substrate W.

[0052]

[0051] To address the ingress of the immersion liquid into the gap 5, at least one drain 10, 20 is provided at the edge of the substrate W to remove the immersion liquid that enters the gap 5. In the embodiment of FIG. 4, two drains 10, 20 are shown, but there may be only one drain or three or more drains. In one embodiment, each of the drains 10, 20 is annular so as to surround the entire circumference of the substrate W.

[0053]

[0052] The main function of the first drain 10 (radially outside the edge of the substrate W / support 21) is to help prevent gas bubbles from entering the immersion space 11 where the liquid of the fluid handling structure IH exists. Such bubbles can have an adverse effect on the imaging of the substrate W. The first drain 10 exists to help avoid the gas in the gap 5 from escaping into the immersion space 11 within the fluid handling structure IH. If gas escapes into the immersion space 11, this may cause bubbles to float within the immersion space 11. If such bubbles are in the path of the projection beam, it may cause imaging errors. The first drain 10 is configured to remove gas from the gap 5 between the edge of the substrate W and the edge of the recess in the substrate support 20 on which the substrate W is disposed. The edge of the recess in the substrate support 20 can be defined by a covering 101 that is optionally spaced apart from the support 21 of the substrate support 20. The covering 101 can be ring-shaped in plan view and surrounds the outer edge of the substrate W. Most of what is extracted into the first drain 10 is gas, and the immersion liquid is only in a very small amount.

[0054]

[0053] The second drain 12 (radially inside the edge of the substrate W / support 21) is provided to help prevent the liquid that finds its way from the gap 5 under the substrate W from interfering with the efficient release of the substrate W from the substrate table WT after imaging. Providing the second drain 20 reduces or eliminates any problems that may arise due to the liquid that finds its way under the substrate W.

[0055]

[0054] As shown in FIG. 4, in one embodiment, the lithographic apparatus comprises a first extraction channel 102 for the passage of two-phase flow. The first extraction channel 102 is formed within a block. The first and second drains 10, 20 are each provided with openings 107, 117 and extraction channels 102, 113. The extraction channels 102, 113 are in fluid communication with the openings 107, 117 through passages 103, 114 respectively.

[0056]

[0055] As shown in FIG. 4, the covering 101 has an upper surface. The upper surface extends circumferentially around the substrate W on the support 21. During use of the lithographic apparatus, the fluid handling structure IH moves relative to the substrate support 20. During this relative movement, the fluid handling structure IH moves across the gap 5 between the covering 101 and the substrate W. In one embodiment, the relative movement is brought about by the substrate support 20 moving under the fluid handling structure IH. In an alternative embodiment, the relative movement is brought about by the fluid handling structure IH moving over the substrate support 20. In a further alternative embodiment, the relative movement is brought about by both the substrate support 20 moving under the fluid handling structure IH and the fluid handling structure IH moving over the substrate support 20. In the following description, the movement of the fluid handling structure IH is used to mean the relative movement of the fluid handling structure IH with respect to the substrate support 20.

[0057]

[0056] <Comparative example> Warpage of the substrate W due to the stacking of the film layers often means that the substrate W assumes an "umbrella" shape, with the center of the substrate W being the highest point (i.e., the point furthest from the substrate support WT), and the substrate W curving downwards radially outwards from the center. To reduce the umbrella-shaped deformation during loading, gas can be blown under the edge region of the substrate W from the substrate support WT. This causes the edge region of the substrate W to deform upwards, relieving any umbrella-shaped deformation and ensuring that the outermost ring in the radial direction of the bar 41 becomes the last contact point between the substrate W and the substrate support WT during loading of the substrate. As a result, variations in friction in the outer peripheral ring of the bar 41 that enhance the reproducibility of substrate loading are reduced. This "edge lift" technique can also be used for substrates W that are not in the shape of an umbrella. For example, flat substrates W, bowl-shaped substrates W, and saddle-shaped substrates W can utilize this technique during unloading of the substrate.

[0058]

[0057] An example of the substrate support WT that implements this "edge lift" function will be described below. This example helps to emphasize aspects of the present invention. FIGS. 5 and 6 show a part of the substrate support 200. The part of the illustrated substrate support 200 can be incorporated into a configuration such as the substrate support 20 shown in FIG. 4. However, a part of the substrate support 200 can also be incorporated into other configurations of the substrate support.

[0059]

[0058] The substrate support 200 includes a support 221. The support 221 includes a plurality of bars 241. When the substrate W is supported by the support 221, the substrate W is in direct contact with the support 221. The support 221 is a part of the substrate support 200 that physically supports the lower side of the substrate W. The distal ends of the bars 241 form a plane on which the lower side of the substrate W is supported. The lower side of the substrate W contacts the distal ends of the bars 241. The bars 241 are on the upper side of the support 221.

[0060]

[0059] As shown in FIGS. 5 and 6, the substrate support 200 further includes a plurality of seals 231, 232, 233. The seals 231, 232, 233 are circumferential rings protruding from the substrate support 200. In this example, there are at least three seals, namely an inner seal 231, an intermediate seal 232 radially outside the inner seal 231, and an outer seal 233 radially outside the intermediate seal 232.

[0061]

[0060] The plurality of seals 231, 232, 233 define a plurality of regions 251, 252 between the substrate support 200 and the substrate W. The multifunctional groove 251 is a region that extends circumferentially around the substrate support 200 between the inner seal 231 and the intermediate seal 232. The fluid extraction groove 252 is a region that extends circumferentially around the substrate support 200 between the intermediate seal 232 and the outer seal 233.

[0062] As shown in FIGS. 5 and 6, the substrate support 200 further includes a plurality of openings 261, 262. In one embodiment, the support 221 includes a multi-functional opening 261 between the inner seal 231 and the intermediate seal 232 (within the multi-functional groove 251), and a fluid extraction opening 262 between the intermediate seal 232 and the outer seal 233 (within the fluid extraction groove 252).

[0063]

[0062] The multi-functional opening 261 may be configured to supply gas to the multi-functional groove 252 or extract gas from the multi-functional groove 252, and the fluid extraction opening 262 may be configured to extract fluid from the fluid extraction groove 252.

[0064]

[0063] The region radially inside the inner seal 231 is the clamp region 253. In one embodiment, the substrate support 200 may further include a clamp opening 263 that is radially inside the inner seal 231 (within the clamp region 253) and is configured to extract gas from the clamp region 253. When the substrate W is loaded onto the substrate support 200, the substrate W is first received by a plurality of e-pins in the extended position (not shown). Next, the e-pins contract, causing the substrate W to descend toward the substrate support 200. When the lower side of the substrate W contacts the plurality of bars 241, the e-pins continue to contract, the substrate W no longer contacts the e-pins, and the substrate W is fully supported by the plurality of bars 241.

[0065]

[0064] In this "loading state" (FIG. 5), gas is supplied to the multi-functional groove 251 by the multi-functional opening 261, thereby increasing the pressure within the multi-functional groove 251. As a result, the pressure within the multi-functional groove 251 becomes greater than the ambient pressure, and an upward force (i.e., a force away from the substrate support 200) is applied to the lower side of the substrate W. This upward force causes the edge of the substrate W to deform upward. This may reduce or completely eliminate the umbrella-shaped deformation. The upward force may even reverse the direction of deformation of the substrate, causing the edge of the substrate W to curve upward (i.e., form a bowl shape).

[0066]

[0065] During the loading stage, gas can be extracted from the clamp region 253 through the clamp opening 263, thereby establishing a negative pressure (a pressure lower than the ambient pressure) in the clamp region 253, and a force is applied in the direction towards the substrate support 200 on the lower side of the substrate W, whereby the substrate W is clamped to the substrate support 200.

[0067]

[0066] The fluid extraction opening 262 may be closed during the loading stage. This means that the fluid extraction opening 262 does not extract fluid.

[0068]

[0067] FIG. 6 shows the subsequent "clamped state". In the clamped state, the immersion fluid that has flowed through the gap 5 between the substrate W and the cover ring 201 also passes through the outer seal 233 and exists in the fluid extraction groove 252. This immersion fluid is extracted by the fluid extraction port 262. Also, in the clamped state, since pressure continues to be supplied to the multifunctional groove 251 through the multifunctional opening 261, the immersion fluid does not pass over the intermediate seal 232. The pressure supplied to the multifunctional groove 251 during this clamped state may be the ambient pressure.

[0069]

[0068] In this clamped state, the multifunctional opening 261 continues to supply gas to the multifunctional groove 251 in order to prevent the immersion fluid from passing over the intermediate seal 232.

[0070]

[0069] This configuration has several drawbacks. First, it is impossible to satisfy the edge lift requirement and the flatness requirement. To obtain the necessary edge lift deformation due to the edge lift force, it is necessary to increase the distance between the inner seal 231 and the intermediate seal 232. However, to avoid the presence of flat bumps in the clamped state, it is necessary to reduce the distance between the inner seal 231 and the intermediate seal 232. Unless otherwise specified, the distance between the seals (or the distance between the circumferential walls in the claims) refers to the distance between the opposing surfaces of the seals. For example, the distance between the inner seal 231 and the intermediate seal 232 is the distance between the radially outer surface of the inner seal 231 and the radially inner surface of the intermediate seal 232.

[0071]

[0070] It is necessary to humidify the air flowing in from the multi-functional opening 261 during the clamping state. This is because if the humidity is too low, an excessive cold load will be applied to the substrate support 200. For example, an excessive cold load is applied around the fluid extraction region 252 and the fluid extraction opening 262. As a result, temporary structural deformation of the substrate support 200 may occur, which may ultimately lead to an overlay penalty. The second drawback of the above example is that when the humidity of the air entering the multi-functional opening 261 during the clamping state is too high, the air may move radially inward toward the clamping region 253. If there is a humidity gradient in the clamping region 253, an electrochemical reaction will occur on the bar 241, leading to flatness drift in the clamping region 253 of the substrate support 200. This means that when the substrate support 200 supports the substrate W, drift occurs in the flatness of the substrate W.

[0072]

[0071] Further, in the above example, uncontrolled air (for example, air containing contaminants or air at an uncontrolled temperature) may flow between the substrate W and the substrate support 200.

[0073]

[0072] <Embodiment> Figures 7 to 10 show a part of the substrate support 300 according to the present invention. The substrate support 300 is similar to the substrate support 200 shown in the comparative example, but includes an additional seal (inner intermediate seal 334) and an additional opening (peripheral opening 364). Similar to the part of the substrate support 200 in the above comparative example, a part of the substrate support 300 can be incorporated into a structure like the substrate support 20. However, the present invention is not limited to this, and a part of the substrate support 300 may be incorporated into a substrate support having a different configuration.

[0074]

[0073] Similar to the comparative example, the substrate support 300 includes a support 321. The support 321 includes a plurality of bars 341. When the substrate W is supported by the substrate support 300, the substrate W is in direct contact with the support 321. The support 321 is a part of the substrate support 300 that physically supports the lower side of the substrate W. The distal ends of the bars 341 form a plane on which the lower side of the substrate W is supported. The lower side of the substrate W contacts the distal ends of the bars 341. The bars 341 are on the upper side of the support 321.

[0075]

[0074] As shown in FIGS. 7-10, the substrate support 300 includes a plurality of seals 331, 332, 333, and 334. These seals 331, 332, 333, and 334 are circumferential rings protruding from the substrate support 300. In one embodiment, there are at least four seals, namely, an inner seal 331, an inner intermediate seal 334 that is radially outside the inner seal 331, an intermediate seal 332 that is radially outside the inner intermediate seal 334, and an outer seal 333 that is radially outside the intermediate seal 332. The inner seal 331 is an example of a first circumferential wall, the inner intermediate seal 334 is an example of a second circumferential wall, the intermediate seal 332 is an example of a third circumferential wall, and the outer seal 333 is an example of a fourth circumferential wall. In the embodiment shown in FIGS. 7-10, the inner seal 331, the inner intermediate seal 334, the intermediate seal 332, and the outer seal 333 are circumferential rings protruding from the surface of the support 321.

[0076]

[0075] The plurality of seals 331, 332, 333, and 334 define a plurality of regions between the substrate support 300 and the substrate W. The multifunctional groove 351 is a region that extends circumferentially around the substrate support 300 between the inner seal 331 and the inner intermediate seal 334. The peripheral groove 354 is a region that extends circumferentially around the substrate support 300 between the inner intermediate seal 334 and the intermediate seal 332. The fluid extraction groove 352 is a region that extends circumferentially around the substrate support 300 between the intermediate seal 332 and the outer seal 333.

[0077]

[0076] In FIGS. 7 - 10, the support 321 further includes a plurality of openings 361, 364, and 362. These are a multi - function opening 361 (within the multi - function groove 351) disposed between the inner seal 331 and the inner intermediate seal 334, a peripheral opening 364 (within the peripheral groove 354) disposed between the inner intermediate seal 334 and the intermediate seal 332, and a fluid extraction opening 362 (within the fluid extraction groove 352) disposed between the intermediate seal 332 and the outer seal 333. The multi - function opening 361 is an example of a first opening, the peripheral opening 364 is an example of a second opening, and the fluid extraction opening 362 is an example of a third opening.

[0078]

[0077] In one embodiment, the multi - function opening 361 is configured to supply and extract gas to and from the multi - function groove 351. However, the multi - function opening 361 may be configured to perform only gas supply. The peripheral opening 364 can be configured to be in fluid communication with the ambient pressure. The ambient pressure can be provided from the atmosphere or from a fluid source within the system. The peripheral opening 364 can also be configured to be in fluid communication with a positive pressure (a pressure higher than the ambient pressure). The fluid extraction opening 362 is configured to extract fluid from the fluid extraction groove 352. The fluid extraction opening 362 is an example of the second opening 117 of the substrate support 20 shown in FIG. 4. Similar to the second opening 117 of the substrate support 20, the fluid extraction opening 362 may be part of a drain system such as the second drain 12 of the substrate support 20, which includes a plurality of channels and passages configured to accommodate the fluid.

[0079]

[0078] Similar to the comparative example, the region radially inside the inner seal 331 is the clamp region 353. In one embodiment, the support 321 may further include a clamp opening 363 radially inside the inner seal 331 (within the clamp region 353) configured to extract gas from the clamp region 353.

[0080]

[0079] Similar to the comparative example, when the substrate W is loaded onto the substrate support 300, the substrate W is first received by a plurality of e-pins (not shown) in the extended position. Next, as the e-pins contract, the substrate W is lowered toward the substrate support 300. When the lower side of the substrate W contacts the plurality of bars 341, the e-pins continue to contract, whereby the substrate W no longer contacts the e-pins and the substrate W is completely supported by the plurality of bars 341.

[0081]

[0080] In this "loading state" (FIG. 7), gas is supplied to the multifunctional groove 351 through the multifunctional opening 361, and the pressure in the multifunctional groove 351 increases. As a result, the pressure in the multifunctional groove 351 becomes greater than the ambient pressure. Since the pressure in the multifunctional groove 351 is greater than the pressure above the substrate W, an upward force (i.e., a force away from the substrate support 300) is applied to the substrate W.

[0082]

[0081] The substrate support 300 is configured such that the multifunctional groove 351 is disposed near the edge of the substrate W. As a result, the upward force applied to the substrate W is applied to the edge region of the substrate W. In the case of a substrate W with a diameter of 300 mm, the edge region may be a region where the distance to the center of the substrate W (i.e., the radial distance) exceeds 135 mm. Generally, the edge region may be a region where the distance to the center of the substrate W exceeds 45% of the diameter of the substrate W. Applying an upward force to this region causes the edge of the substrate W to deform upward. This ensures that the outermost circumferential ring in the radial direction of the bar 342 becomes the last contact point between the substrate support 300 and the substrate W during loading of the substrate W. This may not be the case when an "umbrella"-shaped substrate W is loaded onto the substrate support 300. This reduces the variability of the friction between the outermost circumferential ring in the radial direction of the bar 342 and the lower side of the substrate W, and reduces the load reproducibility of the substrate W.

[0083]

[0082] The peripheral opening 364 and the fluid extraction opening 362 may be closed during the loading stage. This means that the peripheral opening 364 is not in fluid communication with the ambient pressure and the fluid extraction opening 362 does not extract fluid.

[0084]

[0083] In the method of the present invention, gas is extracted from the clamp opening 363 during the loading stage, thereby establishing a negative pressure (a pressure lower than the ambient pressure) in the clamp region 353. Since the pressure in the clamp region 353 is lower than the pressure above the substrate W, a force is applied to the substrate W towards the substrate support 300, whereby the substrate W is clamped to the substrate support 300. This force is applied radially inside the multifunctional groove 361. This means that the edge lift force can be applied while applying the clamp force.

[0085]

[0084] At a certain point, the substrate support 300 transitions from the loading state to the "clamp state". This clamp state is an example of the "normal state". Preferably, the substrate support 300 transitions from the loading state to the clamp state according to the measured value of the pressure in the clamp region 353. Specifically, when the measured value of the pressure in the clamp region 353 falls below a predetermined threshold value, the substrate support 300 transitions from the loading state to the clamp state. However, the present invention is not limited to this, and the substrate support 300 may transition from the loading state to the clamp state according to other measured values or at a predetermined timing.

[0086]

[0085] In the clamp state (FIG. 8), the multifunctional opening 361 can extract gas from the multifunctional groove 351, thereby establishing a negative pressure in the multifunctional groove 351. This means that, similar to the clamp region 353, a clamp force is applied to a part of the lower side of the substrate W corresponding to the multifunctional groove 351. Alternatively, the multifunctional opening 361 may be closed so as not to be in fluid communication with any of the ambient pressure, overpressure, or negative pressure.

[0087]

[0086] In the clamped state, the peripheral opening 364 and the fluid extraction opening 362 are open. That is, the peripheral opening 364 is in fluid communication with the ambient pressure, and the fluid extraction opening 362 extracts fluid from the fluid extraction groove 352. Alternatively, the peripheral opening 364 may be in fluid communication with a positive pressure source. FIG. 8 shows that when the substrate W is in the clamped state, the immersion fluid flowing through the gap 5 between the substrate W and the cover ring 301 also passes between the outer seal 333 and the lower side of the substrate W and is present in the fluid extraction groove 352. This immersion fluid is extracted by the fluid extraction port 362. The extraction pressure of the fluid extraction opening 362, the intermediate seal 332, and the ambient pressure in the ambient groove 354 prevent the immersion fluid from flowing radially inward of the intermediate seal 332.

[0088]

[0087] It is important to prevent the immersion fluid from flowing inward and reaching the multifunctional groove 351 or the multifunctional opening 361. This is because when the multifunctional opening 361 supplies gas, the immersion fluid is blown toward important surfaces such as the grid plate, sensors (transmission image sensor (TIS), (Integrated Lens Interferometer At Scanner) (ILLIAS), parallel ILLIAS (PARIS)), and the upper surface of the substrate W. This can lead to serious system performance problems such as stage positioning measurement (SPM) errors and substrate defects. In the present invention, when the substrate support 300 is in the clamped state, there are two seals (the intermediate seal 332 and the inner intermediate seal 334) between the multifunctional groove 351 and the immersion fluid. This means that the possibility of the immersion fluid reaching the multifunctional groove 351 is significantly lower compared to a comparative example where there is only one seal (the intermediate seal 232) between the immersion fluid and the multifunctional groove 251.

[0089]

[0088] In the clamped state, the clamp opening 363 may continue to extract gas, thereby increasing the magnitude of the pressure difference between the clamp region 353 and the area above the substrate W. Alternatively, the clamp opening 363 can be closed to substantially maintain the magnitude of the pressure within the clamp region 353. As yet another method, gas can be periodically extracted through the clamp opening 363 such that the magnitude of the pressure within the clamp region 353 is substantially maintained.

[0090]

[0089] The substrate support 300 can also be configured to operate in an "alternative state" (see FIG. 9), which is an alternative to the clamped state. In the bypass state, the clamp opening 363 and the multi-functional opening fluid extraction opening 362 operate in the same manner as in the clamped state. However, the peripheral opening 364 may be closed. This means that the peripheral opening 364, and thus the peripheral groove 354, is not in fluid communication with the ambient pressure. Alternatively, the peripheral opening 364 may remain open, but it is not sufficient to prevent the immersion fluid from moving radially inward beyond the intermediate seal 332. As a result, the immersion fluid surrounds the intermediate seal 332 and the outer peripheral ring of the bead 342. In this bypass state, the multi-functional opening 361 supplies ambient pressure or positive pressure to the multi-functional groove 351 to prevent the immersion fluid from moving radially inward towards the clamp region 353 beyond the inner intermediate seal 334. This scenario where the outer peripheral ring of the bead 342 is "wet" may be preferred in some cases because the outer peripheral ring of the bead 342 being "wet" affects the friction between the distal end of the bead 342 and the underside of the substrate W.

[0091]

[0090] In one embodiment, the following operations are performed to unload the substrate W from the substrate support 300. First, the immersion liquid around the substrate W is removed. There is no particular limitation on how the immersion liquid is removed. This may be performed by the channel 13 in the fluid handling structure IH as shown in FIG. 2, or may be performed by the porous member 33 in the fluid handling structure IH as shown in FIG. 3. Next, the multi-functional opening 361 is switched and gas is supplied to the multi-functional groove 351, thereby increasing the pressure in the multi-functional groove 351 as in the loading stage. As a result, the pressure in the multi-functional groove 351 becomes greater than the ambient pressure. Since the pressure in the multi-functional groove 351 is greater than the pressure above the substrate W, an upward force (i.e., a direction away from the substrate support 300) is applied to the lower side of the substrate W.

[0092]

[0091] Next, the clamp opening 363 is closed. As a result, the pressure in the clamp region 353 gradually increases toward the ambient pressure, thereby reducing the clamping force applied to the substrate W. To remove the substrate W from the substrate support 300, an e-pin (not shown) is extended from the retracted position. When the e-pin extends, its distal portion contacts the lower side of the substrate W. As the e-pin continues to extend, the substrate W is lifted from the plurality of bars 341, 342.

[0093]

[0092] In one embodiment, when the substrate W is supported by the substrate support 300, the upper surfaces of the plurality of seals 331, 332, 333, and 334 (i.e., the surfaces of the plurality of seals 331, 332, 333, and 334 that are substantially parallel to the substrate W and closest to the substrate W) do not contact the lower side of the substrate W. However, the distance between the upper surfaces of the plurality of seals 331, 332, 333, and 334 and the lower side of the substrate W is such that at least a partial seal is formed between the upper surfaces of the seals 331, 332, 333, and 334 and the lower side of the substrate W. That is, the plurality of seals 331, 332, 333, and 334 prevent the flow of fluid between the plurality of grooves 351, 352, and 354 and the clamp region 353, but do not completely prevent it.

[0094]

[0093] The distance between the upper surfaces of the seals 331, 332, 333, and 334 and the lower side of the substrate W is preferably less than 10 μm, more preferably less than 5 μm, preferably greater than 1 μm, and more preferably greater than 3 μm.

[0095]

[0094] In one embodiment, the distance between the upper surfaces of the seals 331, 332, 333, and 334 and the lower side of the substrate W may not be the same for each of the seals 331, 332, 333, and 334. For example, for the seals that define the multi-functional groove 351 (i.e., the inner seal 331 and the inner intermediate seal 334), the distance between the upper surface of the seal and the lower side of the substrate W may be smaller. This is to restrict the flow of fluid from the multi-functional groove 351 to other regions, thereby enabling a higher pressure to be established within the multi-functional groove 351 to provide an edge lift function. Further, restricting the flow through the inner seal 331 and the inner intermediate seal 334 is beneficial for separating the multi-functional groove 351 and the clamp region 353 from the surrounding groove 354. To optimize the substrate support 300 for the clamped state, the distance between the upper surface of the outer seal 333 and the lower side of the substrate W may be made smaller than the distance between the upper surface of the intermediate seal 332 and the lower side of the substrate W. To optimize the substrate support 300 for the bypass state, the distance between the upper surface of the intermediate seal 332 and the lower side of the substrate W may be made smaller. This is to increase the capillary force on the immersion fluid in the gap between the intermediate seal 332 and the substrate W and ensure that the intermediate seal 332 is surrounded by the immersion fluid and the burr 342 is "wet".

[0096]

[0095] In the present invention, an edge lift force is applied to the lower side of the substrate W in a region corresponding to the multifunctional groove 351 between the inner seal 331 and the inner intermediate seal 334. During the clamping state, the atmospheric pressure or overpressure required to prevent the immersion fluid from flowing radially inward of the intermediate seal 332 is supplied by the peripheral opening 364. There is an inner intermediate seal 334 between the multifunctional opening 361 and the peripheral opening 364. This means that the magnitude of the edge lift force depends on the distance between the inner seal 331 and the inner intermediate seal 334, and the size of the flatness bump depends on the distance between the inner intermediate seal 334 and the intermediate seal 332. As a result, the distance between the inner seal 331 and the inner intermediate seal 334 (i.e., the size of the multifunctional groove 351) can be made large enough to provide sufficient edge lift force in the loading state.

[0097]

[0096] Separately from this, the distance between the inner intermediate seal 334 and the intermediate seal 332 can also be made small enough to minimize the flatness bumps of the substrate W when the substrate support 300 is in the clamping state. This is different from the comparative example in which the multifunctional opening 261 provides the ambient pressure or overpressure required to prevent the immersion fluid from flowing radially inward of the intermediate seal 232. This means that the problem shown in the comparative example, where the distance between the inner seal 231 and the intermediate seal 232 cannot satisfy the edge lift force requirement and the flatness requirement, is avoided in the present invention.

[0098]

[0097] In consideration of this, in one embodiment, the distance between the inner seal 331 and the inner intermediate seal 334 is greater than the distance between the inner intermediate seal 334 and the intermediate seal 332, and the distance between the intermediate seal 332 and the outer seal 333. As the substrate support 300 configured to support a substrate W with a diameter of 300 mm, the following dimensions are preferable. The radial distance between the inner seal 331 and the inner intermediate seal 334 needs to be 0.5 mm or more, preferably 1 mm or more, and more preferably 1.5 mm or more. This is to ensure that the edge lift force applied to the lower side of the substrate W in the area corresponding to the multifunctional groove 351 is sufficient to deform the edge of the substrate W, so that when the substrate support 300 is in the loading state, the outer peripheral ring of the bar 342 can be ensured to be the last contact point with the lower side of the substrate W. Preferably, the distance between the inner seal 331 and the inner intermediate seal 334 is less than 10 mm.

[0099]

[0098] The distance between the inner intermediate seal 334 and the intermediate seal 332, the distance between the intermediate seal 332 and the outer seal 333, and the distance between the outer seal 333 and the peripheral edge of the substrate W must be small enough so that the multifunctional groove approaches the edge of the substrate W sufficiently. In this context, "sufficiently close" means that the edge lift force applied to the lower side of the substrate W in the area corresponding to the multifunctional groove 351 is close enough so that the edge region of the substrate W deforms upward, and when the substrate support 300 is in the loading state, the outer peripheral ring of the bar 342 can be ensured to be the last contact point with the lower side of the substrate W.

[0100]

[0099] Preferably, the distance between the inner intermediate seal 334 and the intermediate seal 332 is less than 1 mm, more preferably less than 0.8 mm, and even more preferably less than 0.6 mm. Preferably, the distance between the inner intermediate seal 334 and the intermediate seal 332 is greater than 0.2 mm. As described above, this distance ensures that the multifunctional groove 351 is located at a position sufficiently close to the peripheral edge of the substrate W, and minimizes the flatness bumps of the substrate W between the inner intermediate seal 334 and the intermediate seal 332 when the substrate W is clamped to the substrate support 300.

[0101]

[0100] The distance between the radial center of the intermediate seal 332 and the radial center of the outer seal 333 may be about half of the burr pitch (the distance between a plurality of burrs 341). That is, the distance between the radial center of the intermediate seal 332 and the radial center of the outer seal 333 is preferably greater than 30% of the burr pitch, more preferably greater than 40% of the burr pitch, and even more preferably greater than 45% of the burr pitch. The distance between the radial center of the intermediate seal 332 and the radial center of the outer seal 333 is preferably less than 70% of the burr pitch, more preferably less than 60% of the burr pitch, and even more preferably less than 55% of the burr pitch. For example, when the burr pitch is 1.5 mm, the distance between the radial center of the intermediate seal 332 and the radial center of the outer seal 333 is preferably greater than 0.45 mm, more preferably greater than 0.6 mm, and even more preferably greater than 0.68 mm. In this case, the distance between the radial center of the intermediate seal 332 and the radial center of the outer seal 333 is preferably less than 1.05 mm, more preferably less than 0.9 mm, and even more preferably less than 0.83 mm. As described above, the distance between the radial center of the intermediate seal 332 and the radial center of the outer seal 333 is small, ensuring that the multifunctional groove 351 is sufficiently close to the edge of the substrate W. Furthermore, the above-defined range ensures that the balance of the bending moment acting on the substrate W is achieved, thus ensuring the optimal flatness of the substrate W.

[0102]

[0101] Further, the distance between the outer seal 333 and the peripheral edge of the substrate W is preferably less than 5 mm, more preferably less than 3 mm, and even more preferably less than 2.5 mm. The distance between the outer seal 333 and the peripheral edge of the substrate W is preferably greater than 1 mm. As described above repeatedly, this distance is small to ensure that the multifunctional groove 351 is disposed close enough to the peripheral edge of the substrate W.

[0103]

[0102] For a substrate W having a diameter other than 300 mm, the dimensions need to be enlarged or reduced according to the diameter of the substrate W. Generally, the distance between the inner seal 331 and the inner intermediate seal 334 is greater than 0.15% of the diameter of the substrate W, preferably greater than 0.3% of the diameter of the substrate W, more preferably greater than 0.5% of the diameter of the substrate W, and must be less than 3.3% of the diameter of the substrate W. The distance between the inner intermediate seal 334 and the intermediate seal 332 is less than 0.5% of the diameter of the substrate W, preferably less than 0.25% of the diameter of the substrate W, more preferably less than 0.2% of the diameter of the substrate W, and must be greater than 0.05% of the diameter of the substrate W. Further, the distance between the outer seal 333 and the edge of the substrate W is preferably less than 1.7% of the diameter of the substrate W, more preferably less than 1% of the diameter of the substrate W, and even more preferably less than 0.8% of the diameter of the substrate W. The distance between the outer seal 333 and the peripheral edge of the substrate W is preferably greater than 0.3% of the diameter of the substrate W.

[0104]

[0103] It should be noted that the range cited above for the distance between the radius center of the intermediate seal 332 and the radius center of the outer seal 333 is not limited to being advantageous for the above-described embodiment. For example, this range can be implemented in the substrate support 200 of the comparative example to produce the same technical effect (ensuring the flatness of the substrate W by balancing the bending moment).

[0105]

[0104] The width of each of the plurality of seals 331, 332, 333, and 334 (i.e., the radial distance between the inner peripheral edge of the seal and the outer peripheral edge of the seal) is preferably greater than 0.1 mm, more preferably greater than 0.2 mm. The width of each of the plurality of seals 331, 332, 333, and 334 is preferably less than 1 mm, more preferably less than 0.6 mm.

[0106]

[0105] The widths of the plurality of seals 331, 332, 333, and 334 do not have to be the same. The width of some of the seals may be made larger in order to ensure that the ring of the burr 342 can be reliably placed on the upper surface of the seal 332. In one embodiment, the widths of the intermediate seal 332 and the outer seal 333 are larger than the widths of the inner seal 331 and the inner intermediate seal 334. Preferably, the widths of the intermediate seal 332 and the outer seal are greater than 0.4 mm and less than 0.6 mm, for example 0.5 mm. The widths of the inner seal 331 and the inner intermediate seal 334 are preferably less than 0.3 mm, greater than 0.2 mm, for example 0.25 mm.

[0107]

[0106] In one embodiment, the plurality of burrs 341 are arranged in a circumferential ring shape. The outermost circumferential ring of the burr 342 may be arranged on or around the intermediate seal 332. This is because when the substrate support 300 supports the substrate W, it is preferable that the outer peripheral ring of the burr 342 remains dry, that is, does not come into contact with the immersion fluid. This is to prevent wear of the outer peripheral ring of the burr 342 and reduce the risk of edge roll-off (ERO).

[0108]

[0107] In one embodiment, when a substrate W having a diameter of 300 mm is clamped on the substrate support 300, it is preferable that the outermost circumferential ring in the radial direction of the bar 342 is less than 10 mm from the peripheral edge of the substrate W, more preferably less than 5 mm from the peripheral edge of the substrate W, still more preferably less than 4 mm from the peripheral edge of the substrate W, and still more preferably less than 3.5 mm from the peripheral edge of the substrate W. When a substrate W having a diameter of 300 mm is clamped on the substrate support 300, it is preferable that the outermost circumferential ring in the radial direction of the bar 342 is more than 1 mm away from the peripheral edge of the substrate W.

[0109]

[0108] The respective diameters of the bars 341 and 342 may not be the same. For example, each circumferential ring of the bars 342 to 346 may have a different diameter. The diameters of the bars 342 to 346 within the circumferential ring can be determined by the radial distance from the center of the substrate support 300. This is because the hardness of the bar is proportional to its diameter. As a result, by changing the diameters of the bars 341 and 342, the amount of deformation at the interface between the bar and the substrate can be adjusted. This means that the diameters of the bars 341 and 342 can be controlled so that the substrate W remains within the required flatness tolerance range despite the complex pressure profile under the substrate W. The required diameter for each ring of the bars 342 to 346 can be determined by optimization through experiments or simulations.

[0110]

[0109] FIG. 10 shows the five outer circumferential beads 342 to 346. In one embodiment, the diameter of the bead 342 in the outermost circumferential ring in the radial direction is larger than the diameter of the bead 341 in the other circumferential rings. In another embodiment, the outermost circumferential ring in the radial direction of the bead 342, the third outermost circumferential ring in the radial direction of the bead 344, and the fourth outermost circumferential ring 345 in the radial direction have a larger diameter than the beads in the other circumferential rings 343 and 346. Preferably, the diameters of the beads in the outermost circumferential ring 342 in the radial direction, the third outermost circumferential ring 344 in the radial direction, and the fourth outermost circumferential ring 345 in the radial direction are 200 μm to 350 μm, and the diameters of the beads in the other rings 343 and 346 are 150 μm to 250 μm. More preferably, the diameters of the beads in the outermost circumferential ring 342 in the radial direction, the third outermost circumferential ring 344 in the radial direction, and the fourth outermost circumferential ring 345 in the radial direction are 250 μm to 330 μm, and the diameters of the beads in the other circumferential rings 343 and 346 are 190 μm to 240 μm. Even more preferably, the diameters of the beads in the outermost circumferential ring 342 in the radial direction, the third outermost circumferential ring 344 in the radial direction, and the fourth outermost circumferential ring 345 in the radial direction are 260 μm to 280 μm, for example 270 μm, and the diameters of the beads in the other rings 343 and 346 are 200 μm to 220 μm, for example 210 μm.

[0111]

[0110] Depending on the configuration of the substrate support 300, the ratio of the diameter of the bar 341 to the diameters of the other bars 341 may be important in order to ensure the flatness of the substrate W. Considering this, in one embodiment, the diameters of the bars in the outermost circumferential ring 342 in the radial direction, the third outermost circumferential ring 344 in the radial direction, and the fourth outermost circumferential ring 345 in the radial direction are more than 10% larger than the diameters of the bars in the other rings 343 and 346, preferably more than 20% larger than the diameters of the bars in the other rings 343 and 346, and even more preferably more than 25% larger than the diameters of the bars in the other rings 343 and 346. In an embodiment, the diameters of the bars 342, 344, and 345 are less than 100% larger than the diameters of the bars in the other rings 343 and 346, preferably less than 50% of the diameters of the bars in the other rings 343 and 346, and even more preferably less than 30% of the diameters of the bars in the other rings 343 and 346.

[0112]

[0111] When adjusting the relative ratio of the diameters of the bars 341 and 342, it is preferable to increase the diameters of the bars 341 and 342 rather than decreasing the diameters of the bars 341 and 342. This is because the bars 341 and 342 with small diameters are likely to wear out quickly, meaning that the substrate support 300 (or the support 321) needs to be replaced more regularly. In order to avoid the bars 341 and 342 from wearing out rapidly, it is necessary to make the diameters of all the bars 341 and 342 larger than 150 μm.

[0113]

[0112] To adjust the rigidity of the bars 341 and 342, other techniques can also be used, such as changing the material or applying coatings such as diamond and DLC. However, since the rigidity of the substrate W is typically lower than that of the bars 341 and 342, the deformation at the interface between the substrate and the bars is not significantly affected by the material or coating of the bars. As a result, these techniques are not particularly effective in controlling the flatness of the substrate W.

[0114]

[0113] In the above embodiment, the bar pitch (the distance between bars 341 and 342) is preferably greater than 0.5 mm, more preferably greater than 1 mm, and even more preferably greater than 1.4 mm. The bar pitch is preferably less than 3 mm, more preferably less than 2 mm, even more preferably less than 1.6 mm, for example, 1.5 mm.

[0115]

[0114] Controlling the flatness of the substrate W on the substrate support 300 by adjusting the bar diameter according to its radial position is not limited to the arrangement of the seals 331, 332, 333, and 334 described in the present invention. This technique and the above dimensions can be implemented in a wide range of substrate supports 300 with different seal arrangements.

[0116]

[0115] The height of bar 341 (i.e., the dimension from the surface of the support 321 to the distal end of the bar) may be about 150 μm. However, bar 341 may be any suitable height.

[0117]

[0116] The gases supplied through the openings 361, 362, 363, and 364, for example, through the multi-functional opening 361 in the loading state and through the peripheral opening 364 in the clamping state, are not particularly limited. For example, clean dry air (CDA), humidified air, or N2 can be supplied. Preferably, humidified air is supplied particularly through the peripheral opening 364 in the loading state. This is because CDA with a very low humidity can evaporate the immersion fluid on the outer seal 333, resulting in a large cooling load on the outer seal 333. This can cause temporary structural deformation of the substrate support 300 and lead to an overlay penalty. Humidified air means that less immersion fluid evaporates from around the outer seal 333, reducing the cooling load.

[0118]

[0117] In the substrate support 200 of the comparative example shown in FIGS. 5 and 6, it is not preferable to supply humidified air to the multifunctional opening 261 during the clamping state. This is because there is a risk that moisture will move radially inward toward the clamp region 253, which can cause an electrochemical reaction on the burr 341 in the clamp region 353 and lead to drift in the flatness of the substrate W. However, in the present invention, two seals (inner seal 331 and inner intermediate seal 334) are provided between the peripheral opening 364 (which supplies humidified air in the clamped state) and the clamp region 353. As a result, any moisture that enters from the peripheral opening 364 reaching the clamp region 353 is significantly suppressed. The presence of these two seals 331 and 334 between the peripheral opening 364 and the clamp region 353 also minimizes the risk of uncontrolled air (air containing contaminants and / or air having an uncontrolled temperature) flowing between the substrate W and the substrate support 300.

[0119]

[0118] In the above description, in each of the groove regions 351, 352, 354 and the clamp region 353, a single opening 361, 362, 363, 364 is mentioned. The openings 361, 362, 363, 364 can extend circumferentially across the entire periphery of the substrate support 300. Alternatively, the openings 361, 362, 363, 364 may be circular holes. Preferably, a plurality of hole-shaped openings are evenly distributed around each of the regions 351, 352, 353, 354. If there are a plurality of hole-shaped openings within each region, each opening within the region can be configured in the same way (i.e., the same way as the openings already defined within a particular region). For example, the fluid extraction groove 352 may have a plurality of openings, and each opening may be configured to extract fluid in the same way as the fluid extraction opening 362. However, the additional openings may be configured to operate in a different way from the already defined openings. For example, the fluid extraction groove 352 may further include an opening configured to supply fluid. The multi-functional opening 361 within the multi-functional groove 351 is configured to supply and / or extract gas. If there are a plurality of openings within the multi-functional groove 351, each opening may be configured to perform both gas extraction and supply. Alternatively, some openings may be configured only for gas supply and other openings may be configured only for gas extraction.

[0120]

[0119] The multi-functional opening 361 is a restrictive feature within the fluid circuit. Therefore, the diameter of the multi-functional opening 361 may be smaller than the diameter of the surrounding opening 364. Preferably, the diameter of the multi-functional opening 361 is 100 μm to 200 μm. For the other openings 362, 363 and 364, the diameter is not particularly limited. In order for the fluid to flow freely and minimize the risk of blockage, it is preferable that their diameters are large. However, the diameters of these openings 362, 363 and 364 must be small enough to fit between the seals.

[0121]

[0120] The mechanism for opening and closing these openings 361, 362, 363, and 364 is not particularly limited, and any standard valve or equivalent can be used. Similarly, the system for supplying gas to and extracting gas from the openings 361, 362, 363, and 364 (providing positive and negative pressures) is not particularly limited, and can include any suitable standard components or methods.

[0122]

[0121] <Multi-functional channel>

[0123]

[0122] As described above in connection with FIG. 4, the openings 107, 117 on the upper surface of the substrate support WT may be connected to the channels 102, 113 within the substrate support WT via the passages 103, 114. The channels 102, 113 are cavities extending around the substrate support WT and can carry fluid between the openings 107, 117 within the substrate support WT and, for example, a fluid management system external to the substrate support WT. WT. The passages 103, 114 may be substantially vertical holes extending upward from the channels 102, 113 to the openings 107, 117, facilitating fluid communication therebetween.

[0124]

[0123] FIG. 11A shows an example of a channel. The illustrated channel may be a multi-functional channel 381. As shown in FIG. 11A, a number of multi-functional passages 371 can extend vertically upward from the multi-functional channel 381. The openings at the ends of the multi-functional passages 371 on the opposite side of the multi-functional channel 381 may be multi-functional openings 361. The multi-functional channel 381 may be connected to an external fluid management system 391 at a connection point 382. The fluid management system 391 can control the inflow and outflow of fluid to and from the multi-functional channel 381. The fluid management system 391 may include, for example, a flow restrictor (not shown).

[0125]

[0124] The multi-functional channel 381 may be circular, but does not form a complete circle. This may be because there is a discontinuity 385 in the circle formed by the multi-functional channel 381. This may mean that the fluid cannot flow around the entire multi-functional channel 381 without changing direction from the fluid management system 391. The discontinuity 385 may be disposed on the opposite side of the connection point 382 of the multi-functional channel 381. That is, the discontinuity 385 and the connection point 382 in the multi-functional channel 381 may be approximately 180° apart.

[0126]

[0125] To provide the above-described edge lift force, gas can flow from the fluid management system 391 into the multi-functional channel 381 through the connection point 382. After entering the multi-functional channel 381, the gas flow is split, and approximately half of the gas flow moves in the right direction (i.e., counterclockwise as shown in FIG. 11A), and the remaining half of the gas flow can flow in the left direction (i.e., clockwise as shown in FIG. 11A). As the gas flow passes through the multi-functional passage 371, a part of the gas flow flows upward through the multi-functional passage 371. A part of this gas flow then passes through the multi-functional opening 361 and flows into the multi-functional groove 351, resulting in an increase in pressure within the multi-functional groove 351. The gas flows in the left and right directions can move around the multi-functional channel 381 until they reach the discontinuity 385. By doing so, the gas flows in the left and right directions each move half way around the multi-functional channel 381, thereby supplying gas to all of the multi-functional passages 371. In this way, an edge lift force can be applied across the entire circumference of the substrate W.

[0127]

[0126] To effectively provide the edge lift function, it is desirable that the flow rate through each of the multi-functional passages 371 is substantially the same. If the flow rate through each of the multi-functional passages 371 is not the same, especially when the flow rate of the multi-functional passage 371 in some regions is greater than that of the multi-functional passage 371 in other regions, the substrate W may tilt during loading due to the application of the edge lift force. To ensure that the flow rate in each of the multi-functional passages 371 is substantially the same, it is desirable that the flow rate in the multi-functional channel 381 is substantially uniform around its circumference.

[0128]

[0127] The multi-functional channel 381 and the multi-functional passage 371 may be small due to limited geometric constraints within the substrate support WT. The limited geometric constraints exist because there are many features that need to be accommodated within the substrate support WT, such as channels corresponding to each of the different types of openings, cooling channels, heaters, etc.

[0129]

[0128] Due to the small size of the multi-functional channel 381, pressure loss may occur when gas flow flows from the fluid management system 391 to the multi-functional opening 361. That is, the pressure of the fluid in the multi-functional channel 381 may decrease as the distance from the connection point 382 increases. For example, there may be a pressure difference of about 0.01 - 0.05 bar (1 - 5 kPa) between the connection point 382 and the portion of the multi-functional channel 381 adjacent to the discontinuity 385. This may mean that the edge lift force provided to a part of the substrate W located near the connection point 382 is greater than the edge lift force provided to a part of the substrate W located near the discontinuity 385. Applying a non-uniform edge lift force may cause a non-zero resultant moment to act on the substrate W and tilt the substrate W during loading.

[0130]

[0129] Further, due to the pressure difference within the multi-functional channel 381, the substrate support WT may be deformed. As a result, the flatness of the substrate support WT and the substrate W supported by the substrate support WT may decrease. Thereby, defects may occur in the pattern printed on the substrate W. Further, when the substrate support WT is formed by laminating two or more layers, the layers may be delaminated due to the high pressure difference within the multi-functional channel 381.

[0131]

[0130] In order to improve the uniformity of the edge lift force around the circumference of the substrate W (even though the pressure within the multi-functional channel 381 changes), the multi-functional opening 361 can be made smaller to limit the flow rate passing therethrough. For example, the diameter of the multi-functional opening 361 may be about 0.15 mm. This means that the risk of clogging may increase. Further, this means that it is necessary to manufacture the multi-functional opening 361 with high precision (that is, a low tolerance range). This is because a deviation in the diameter of the multi-functional opening may lead to a change in the flow rate passing through the multi-functional opening when the edge lift force is applied. The conditions for manufacturing the multi-functional opening 361 with a low tolerance range mean that the manufacturing and cleaning processes may become complicated. Further, when the multi-functional opening 361 is manufactured inaccurately or when the multi-functional opening 361 is clogged, the substrate W may be deformed due to the non-uniform edge lift force resulting from being applied to the substrate W.

[0132]

[0131] Figure 11B shows an alternative configuration for supplying fluid to the multi-functional opening 361. In Figure 11B, three multi-functional channels 381a, 381b, and 381c are provided. Each of the multi-functional channels 381a, 381b, and 381c may correspond to a part of the circumference of the substrate support WT such that the multi-functional channels 381a, 381b, and 381c can provide fluid to the multi-functional passage 371 across the entire circumference of the substrate support WT. Each of the multi-functional channels 381a, 381b, and 381c may be of the same size. For example, the three multi-functional channels 381a, 381b, and 381c may each correspond to approximately 120° of the circumference of the substrate support WT. Discontinuities 385ac, 385ab, and 385bc may exist between each of the multi-functional channels 381a, 381b, and 381c. Each multi-functional channel 381a, 381b, and 381c may be directly connected to the fluid management system 391. That is, each multi-functional channel 381a, 381b, and 381c can be connected to the fluid management system 391 via its own connection means (e.g., a pipe or a tube). The connection points 382a, 382b, and 382c of each of the multi-functional channels 381a, 381b, and 381c may be arranged approximately at the center of the multi-functional channels 381a, 381b, and 381c.

[0133]

[0132] As described above, by providing a plurality of the multi-functional channels 381a, 381b, and 381, the inclination of the substrate W can be suppressed. This is because even if the flow rates in each of the multi-functional channels 381a, 381b, and 381c are non-uniform, the tilting moments applied to the substrate W cancel each other out, so that the resultant moment when the substrate W is flat becomes almost zero.

[0134]

[0133] Also, by providing a plurality of multi-functional channels 381a, 381b, and 381c, the size (circumferential direction) of each multi-functional channel 381a, 381b, and 381c can be made smaller than in the configuration where there is only one multi-functional channel 381. For example, in a configuration having three multi-functional channels 381a, 381b, and 381c, the size (circumferential direction) of each multi-functional channel 381a, 381b, and 381c may be one-third of the size (circumferential direction) of the configuration having a single multi-functional channel 381.

[0135]

[0134] Also, by providing a plurality of multi-functional channels 381a, 381b, and 381c, the flow rate flowing through each multi-functional channel 381a, 381b, and 381c can be made smaller than in the configuration where there is only one multi-functional channel 381. For example, in a configuration having three multi-functional channels 381a, 381b, and 381c, the flow rate in each multi-functional channel 381a, 381b, and 381c may be one-third of the flow rate in the multi-functional channel of the configuration having a single multi-functional channel 381.

[0136]

[0135] When the flow rate in the multi-functional channels 381a, 381b, and 381c decreases, it means that the magnitude of the pressure drop of the fluid flowing through the multi-functional channels 381a, 381b, and 381c decreases. This means that the pressure difference in the multi-functional channels 381a, 381b, and 381c becomes smaller (compared to the pressure difference in the multi-functional channel 381 in the configuration where there is only one multi-functional channel 381). This means that the occurrence of warping of the substrate support and / or peeling of the adhesive layer can be reduced. This also means that a multi-functional opening 361 having a larger diameter can be provided without the risk of reducing the uniformity of the edge lift force provided on the lower side of the substrate W. By being able to increase the diameter of the multi-functional opening 361, the possibility of clogging is reduced, and the manufacturing process and the cleaning process can be simplified.

[0137]

[0136] The fluid management system 391 may include adjustable flow restrictors for each of the multi-functional channels 381a, 381b, and 381c. The adjustable flow restrictors may be configured to individually adjust the flow rate of the fluid provided to each of the three multi-functional channels 381a, 381b, and 381c. The adjustable flow restrictors may be electrical and / or mechanical. The exact configuration of the adjustable flow restrictors may not be particularly limited. Using the adjustable flow restrictors may make it possible to calibrate the flow rates provided to each of the multi-functional channels 381a, 381b, and 381c to ensure that the edge lift forces provided to each of the three portions of the substrate W corresponding to the three multi-functional channels 381a, 381b, and 381c are the same. This can further ensure that the substrate W does not tilt during loading. In the calibration process, factors such as clogging of the multi-functional opening 361 and variations in the size of the multi-functional opening 361 may be considered. As a result, by providing a plurality of multi-functional channels 381a, 381b, and 381c, it is possible to ensure that the substrate W does not tilt even if the multi-functional opening 361 becomes clogged or the size of the multi-functional opening 361 varies. This means that manufacturing errors and clogging can be reduced, making the operation of the multi-functional opening 361 more robust. This also means that the manufacturing tolerance can be expanded (i.e., relaxed), and the manufacturing process can be made simpler.

[0138]

[0137] FIG. 12 shows diagrams of the moment about the horizontal axis (M) with respect to the tilt angle (0) at several flow rates for a substrate support WT having a single multi-functional channel and a substrate support WT having three multi-functional channels 381a, 381b, and 381c. Specifically, the various dashed lines in FIG. 12 correspond to a substrate support WT having a single multi-functional channel 381 when the flow rate in the multi-functional channel 381 is 0 NLM (normal liter / minute), 1.5 NLM, and 5 NLM. The solid line in FIG. 12 corresponds to a substrate support WT having three multi-functional channels 381a, 381b, and 381c when the total flow rate of the three multi-functional channels 381a, 381b, and 381c is 5 NLM.

[0139]

[0138] When the substrate W is placed on the substrate support WT, the tilt angle of the substrate W becomes the angle of tilt, which means that the resultant moment around the horizontal axis becomes zero. This angle of tilt can be called the stable tilt angle. For a substrate support WT having a single multifunctional channel 381, as the flow rate increases, the magnitude of the stable tilt angle increases. When the flow rate through the single multifunctional channel 381 is 0 NLM, due to the influence of other openings in the substrate support WT such as the clamp opening 363, the stable tilt angle may not become zero. The stable tilt angle at a flow rate of 5 NLM may be one-tenth smaller for a substrate support WT having three multifunctional channels 381a, 381b, and 381c than for a substrate support WT having a single multifunctional channel 381. The stable tilt angle for a substrate support WT having three multifunctional channels 381a, 381b, and 381c at 5 NLM may not be zero. This can be due to the influence of other openings in the substrate support WT such as the clamp opening 363.

[0140]

[0139] With reference to the configuration having three multifunctional channels 381a, 381b, and 381c, it was described above that a plurality of multifunctional channels are provided. However, by providing a configuration in which the number of multifunctional channels is two or more, the above-described technical effects can also be obtained. For example, the number of multifunctional channels may be 2, 3, 4, 5, or 10. Providing more multifunctional channels may mean that the control over the tilt of the substrate W is improved and the pressure difference within the multifunctional channels 381a, 381b, and 381c can be further reduced. However, providing more multifunctional channels 381a, 381b, and 381c may also make the manufacture of the substrate support WT more difficult. By providing three multifunctional channels 381a, 381b, and 381c, the above-described technical effects are realized without overly complicating the manufacturing process.

[0141] Regarding the provision of multiple channels, although it has been described above in relation to the multi-functional channel 381, this technique can also be implemented in other channels within the substrate support WT.

[0142] <General>

[0141] The material of the substrate support 300 is not particularly limited and may be any suitable material known in the art. Preferably, the substrate support 300 may be made of silicon carbide (SiSiC).

[0143]

[0142] The manufacture of the substrate support 300 may include standard techniques known in the art. Some of the openings 361, 362, 363 and 364 may be too small for methods such as electrical discharge machining (EDM). In this case, laser drilling can be utilized.

[0144]

[0143] The present invention can provide a lithographic apparatus. The lithographic apparatus can have any / all of the other features or components of the lithographic apparatus as described above. For example, the lithographic apparatus may optionally include at least one or more of a radiation source SO, an illumination system IL, a projection system PS, a substrate table WT, etc.

[0145]

[0144] Specifically, the lithographic apparatus can include a projection system PS configured to project a radiation beam B towards an area on the surface of the substrate W. The lithographic apparatus may further include a substrate support 300 as described in any of the above embodiments and variations.

[0146]

[0145] Although specific mention has been made in this specification of the use of the lithographic apparatus in IC manufacturing, it should be understood that the lithographic apparatus described in this specification may have other uses. Possible other uses include the manufacture of integrated optical systems, guidance patterns and detection patterns for magnetic domain memories, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads, etc.

[0147]

[0146] Embodiments of the present invention may be implemented, if the circumstances allow, in hardware, firmware, software, or any combination thereof. Embodiments of the present invention may also be implemented as instructions stored on a machine-readable medium and readable and executable by one or more processors. The machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer device). For example, the machine-readable medium may include read-only memory (ROM), random access memory (RAM), magnetic storage media, optical storage media, flash memory devices, or electrical, optical, acoustic, or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.). Also, in this specification, firmware, software, routines, instructions may sometimes be described as performing some action. However, such descriptions are for convenience only, and such actions are actually performed by a computer device, processor, controller, or other device that executes firmware, software, routines, instructions, etc., and it should be understood that actuators or other devices may interact with the physical world at that time.

[0148]

[0147] Although specific reference has been made in this specification to embodiments of the present invention in the context of a lithographic apparatus, embodiments of the present invention can also be used in other apparatuses. Embodiments of the present invention may form part of any apparatus for measuring or processing an object such as a mask inspection apparatus, a metrology apparatus, or a wafer (or other substrate) or a mask (or other patterning device). These apparatuses are sometimes generally referred to as lithography tools.

[0149]

[0148] Although specific reference has been made above to the use of embodiments of the present invention in the context of optical lithography, it will of course be appreciated that the present invention is not limited to optical lithography if the circumstances allow.

[0150]

[0149] As described above, specific embodiments of the present invention have been explained. However, it is obvious that the present invention can be implemented in modes other than those described above. The above description is intended as an illustration rather than a limitation. Therefore, as will be apparent to those skilled in the art, modifications may be made to the invention described herein without departing from the scope of the appended claims.

Claims

1. A substrate support configured to support a substrate within a lithographic apparatus, a first circumferential wall, a first opening that is radially outside the first circumferential wall and configured to supply and / or extract gas, a second circumferential wall that is radially outside the first opening, a second opening that is in fluid communication with the ambient pressure and is radially outside the second circumferential wall, a third circumferential wall that is radially outside the second opening, a third opening that is radially outside the third circumferential wall and configured to extract fluid, and a fourth circumferential wall that is radially outside the third opening, the substrate support comprising.

2. further comprising a fourth opening that is radially inside the first circumferential wall and configured to extract gas, and / or the substrate support is configured such that the first circumferential wall, the second circumferential wall, the third circumferential wall, and the fourth circumferential wall form at least a partial seal with the bottom surface of the substrate, the substrate support according to claim 1.

3. The distance between the bottom surface of the substrate and the upper surfaces of the third circumferential wall and the fourth circumferential wall is greater than that of the first circumferential wall and the second circumferential wall, and / or the distance between the bottom surface of the substrate and the upper surface of at least one of the first circumferential wall, the second circumferential wall, the third circumferential wall, and the fourth circumferential wall is between 1 and 10 μm, preferably between 1 and 5 μm, more preferably between 3 and 5 μm, the substrate support according to claim 2.

4. The substrate support is configured such that when gas is supplied through the first opening, the pressure in the first region between the first circumferential wall and the second circumferential wall can be made greater than the ambient pressure around the substrate, and / or the widths of the third circumferential wall and the fourth circumferential wall are greater than those of the first circumferential wall and the second circumferential wall, and / or the distance between the first circumferential wall and the second circumferential wall is greater than the distance between the second circumferential wall and the third circumferential wall and the distance between the third circumferential wall and the fourth circumferential wall, and / or the distance between the second circumferential wall and the third circumferential wall is less than 0.5% of the diameter of the substrate, preferably less than 0.25% of the diameter of the substrate, more preferably less than 0.2% of the diameter of the substrate and greater than 0.05% of the diameter of the substrate, the substrate support according to any one of claims 1 to 3.

5. The distance between the first circumferential wall and the second circumferential wall is greater than 0.5 mm, preferably greater than 1 mm, more preferably greater than 1.5 mm and less than 10 mm, and / or the distance between the second circumferential wall and the third circumferential wall is less than 1 mm, preferably less than 0.8 mm, more preferably less than 0.6 mm and greater than 0.2 mm, and / or the distance between the first circumferential wall and the second circumferential wall is greater than 0.15% of the diameter of the substrate, preferably greater than 0.3% of the diameter of the substrate, more preferably greater than 0.5% of the diameter of the substrate and less than 3.3% of the diameter of the substrate, and / or the distance between the radial center of the third circumferential wall and the radial center of the fourth circumferential wall is greater than 0.45 mm, preferably greater than 0.6 mm, preferably greater than 0.68 mm and less than 1.05 mm, preferably less than 0.9 mm, more preferably less than 0.83 mm, the substrate support according to any one of claims 1 to 4.

6. The substrate support according to any one of claims 1 to 5, further comprising a plurality of bars arranged in a plurality of circumferential rings.

7. The diameter of the beads depends on their radial position on the substrate support, and / or the outermost circumferential ring of beads is arranged on or around the third circumferential wall, and / or the diameter of the beads in the outermost circumferential ring, the third outermost circumferential ring, and the fourth outermost circumferential ring is larger than the diameter of the beads in the other rings. The substrate support according to claim 6.

8. The diameter of the curl in the outermost circumferential ring in the radial direction, the third outermost circumferential ring in the radial direction, and the fourth outermost circumferential ring in the radial direction is more than 10% larger than the diameter of the curl in other rings, preferably more than 20% larger than the diameter of the curl in other rings, more preferably more than 25% larger than the diameter of the curl in other rings, less than 100% larger than the diameter of the curl in other rings, preferably less than 50% of the diameter of the curl in other rings, preferably less than 30% of the diameter of the curl in other rings, and / or the diameter of the curl in the outermost circumferential ring in the radial direction, the third outermost circumferential ring in the radial direction, and the fourth outermost circumferential ring in the radial direction is between 200 μm and 350 μm, and the diameter of the curl in other rings is between 150 μm and 250 μm. Preferably, the diameter of the curl in the outermost circumferential ring in the radial direction, the third outermost circumferential ring in the radial direction, and the fourth outermost circumferential ring in the radial direction is between 250 pm and 330 pm, and the diameter of the curl in other rings is between 190 μm and 240 μm. More preferably, the diameter of the curl in the outermost circumferential ring in the radial direction, the third outermost circumferential ring in the radial direction, and the fourth outermost circumferential ring in the radial direction is between 260 μm and 280 μm, and the diameter of the curl in other rings is between 200 μm and 220 μm, and / or the distance between the radial center of the third circumferential wall and the radial center of the fourth circumferential wall is larger than 30% of the curl pitch, preferably larger than 40% of the curl pitch, preferably larger than 45% of the curl pitch, less than 70% of the curl pitch, preferably less than 60% of the curl pitch, more preferably less than 55% of the curl pitch, the substrate support according to claim 6 or 7.

9. The diameter of the first opening is smaller than that of the second opening, and / or the second opening is further in fluid communication with a positive pressure source, the substrate support according to any one of claims 1 to 8.

10. The second opening is configured to supply dry gas or humidified gas, the substrate support according to claim 9.

11. The substrate support is made of SiSiC, and / or a plurality of first openings are distributed in the circumferential direction around the substrate support, a first part of the multi-functional opening is in fluid communication with a first multi-functional channel, and a second part of the multi-functional opening is in fluid communication with a second multi-functional channel. The substrate support according to any one of claims 1 to 10.

12. A third part of the multi-functional opening is in fluid communication with a third multi-functional channel. The substrate support according to claim 11.

13. The first multi-functional channel, the second multi-functional channel, and the third multi-functional channel are cavities in the substrate support extending around a part of the substrate support in the circumferential direction, and / or the first multi-functional channel, the second multi-functional channel, and the third multi-functional channel are each directly connected to a fluid management system, whereby the flow rate of the gas supplied to each of the first multi-functional channel, the second multi-functional channel, and the third multi-functional channel can be individually controlled. The substrate support according to claim 12.

14. A lithographic apparatus comprising the substrate support according to any one of claims 1 to 13.

15. A method of loading a substrate onto a substrate support having a first circumferential wall, a second circumferential wall radially outside the first circumferential wall, a third circumferential wall radially outside the second circumferential wall, and a fourth circumferential wall radially outside the third circumferential wall, wherein there is a first region between the first circumferential wall and the second circumferential wall, a second region between the second circumferential wall and the third circumferential wall, and a third region between the third circumferential wall and the fourth circumferential wall, the method comprising: A substrate loading step, in which gas is supplied to the first region; and A substrate clamping step, in which the gas is extracted from the first region and fluid is extracted from the third region.

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