Covering, substrate support, and lithography equipment

Abstract

This specification discloses a covering for use as a substrate support, comprising: a flexible structure having an opening for receiving a substrate; a closed region within the covering; and a fluid conduit configured to supply fluid to and / or receive fluid from the closed region, wherein the flexible structure is configured to change between a first state and a second state in response to fluid inflow into or outflow from the closed region, and in the first state, the diameter of the opening is larger than in the second state.

Description

Technical Field

[0001] (Cross - reference to related applications)

[0001] This application claims priority to European Application 23166755.1 filed on April 5, 2023 and European Application 23215658.8 filed on December 11, 2023, the entire contents of which are incorporated herein by reference.

[0002]

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

Background Art

[0003]

[0003] A lithographic apparatus is a machine configured 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 referred to as a "design layout" or "design", onto a layer of radiation - sensitive material (resist) provided on a substrate (e.g., a wafer) using a projection system. Known lithographic apparatuses include so - called steppers, in which each target portion is irradiated by exposing the entire pattern once onto the target portion, and so - called scanners, in which each target portion is irradiated by scanning the pattern in a given direction (the "scan" direction) with a radiation beam while synchronously scanning the substrate parallel or antiparallel to this direction.

[0004]

[0004] As semiconductor manufacturing processes continue to advance, the dimensions of circuit elements have continuously decreased, while the number of functional elements such as transistors per device has steadily increased over decades, following a trend commonly known as Moore's Law. To keep up with Moore's Law, the semiconductor industry is pursuing technologies that enable the creation of increasingly smaller features. To project patterns onto a substrate, lithography equipment can use electromagnetic radiation. The wavelength of this radiation determines the minimum size of the feature that can be patterned on the substrate. Typical wavelengths currently in use are 365 nm (i-line), 248 nm, 193 nm, and 13.5 nm.

[0005]

[0005] Further improvement in the resolution of smaller features can be achieved by providing an immersion fluid with a relatively high refractive index, such as water, on the substrate during exposure. Since exposure radiation has shorter wavelengths in a fluid than in a gas, the effect of the immersion fluid is that it enables imaging of smaller features. The effect of the immersion fluid can also be thought of as increasing the effective numerical aperture (NA) and depth of field of the system.

[0006]

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

[0007]

[0007] According to a first aspect of the present invention, a covering for use as a substrate support is provided, comprising: a flexible structure having an opening for receiving a substrate; a closed region within the covering; and a fluid conduit configured to supply fluid to and / or receive fluid from the closed region, wherein the flexible structure is configured to change between a first state and a second state in response to fluid inflow into or outflow from the closed region, and in the first state, the diameter of the opening is larger than in the second state.

[0008]

[0008] According to a second aspect of the present invention, a substrate support is provided which is configured to support a substrate and is equipped with a covering according to the first aspect.

[0009]

[0009] According to a third aspect of the present invention, a lithography apparatus is provided that is equipped with a substrate support according to the second aspect.

[0010]

[0010] According to a fourth aspect of the present invention, a method for supporting a substrate is provided, which includes the use of a substrate support according to the second aspect.

[0011]

[0011] A fifth aspect of the present invention provides a method for performing lithography, comprising projecting a radiation beam onto a substrate in an exposure operation, wherein the substrate is supported by a substrate support according to the second aspect.

[0012]

[0012] According to a sixth aspect of the present invention, a covering for use as a substrate support is provided, comprising an aperture mechanism having an opening for receiving a substrate, wherein the aperture mechanism comprises a plurality of curved segments configured to move in a direction that rotates at least partially about a center point of the opening so as to change the diameter and / or shape of the opening.

[0013]

[0013] According to a seventh aspect of the present invention, a substrate support is provided which is configured to support a substrate and is equipped with a covering according to a sixth aspect.

[0014]

[0014] According to an eighth aspect of the present invention, a lithography apparatus is provided that is equipped with a substrate support according to the seventh aspect.

[0015]

[0015] According to a ninth aspect of the present invention, a method for supporting a substrate is provided, which includes the use of a substrate support according to a seventh aspect.

[0016]

[0016] According to a tenth aspect of the present invention, a method for performing lithography is provided, comprising projecting a radiation beam onto a substrate in an exposure operation, wherein the substrate is supported by a substrate support according to a seventh aspect.

[0017]

[0017] Further embodiments, features and advantages of the present invention, as well as 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 explanation of the drawing]

[0018]

[0018] Next, embodiments of the present invention will be described as merely examples with reference to the attached schematic drawings. In the drawings, corresponding reference symbols indicate corresponding parts.

[0019] [Figure 1] This is a schematic diagram of a lithography machine. [Figure 2] This is a cross-sectional view of a substrate support that does not conform to the present invention. [Figure 3A-3B] This is a schematic cross-sectional view of the covering according to the first embodiment. [Figure 4A-4B] This is a schematic cross-sectional view of the covering according to the second embodiment. [Figure 5A-5B] This is a schematic cross-sectional view of the covering according to the third embodiment. [Figure 6A-6B] This is a schematic cross-sectional view of the covering according to the fourth embodiment. [Figures 7A-7B] This is a schematic plan view of the covering according to the fifth embodiment. [Figure 8] This is a schematic cross-sectional view of a substrate support according to one embodiment.

[0020] The features shown in the drawings are not necessarily to scale, and the sizes and / or arrangements shown are not limiting. It will be understood that the drawings may include optional features that may not be essential to the invention. Also, not all features of the device are shown in each drawing, and in some cases only a portion of the components relevant to the description of a particular feature may be shown.

Embodiments of the Invention

[0021]

[0019] In this document, the terms "radiation" and "beam" are used to encompass all types of electromagnetic radiation including ultraviolet light (e.g., having wavelengths of 365 nm, 248 nm, 193 nm, 157 nm, or 126 nm).

[0022]

[0020] As used herein, the terms "reticle", "mask", or "patterning device" can be broadly construed to refer to a general-purpose patterning device that can be used to impart a patterned cross-section to an incoming radiation beam corresponding to a pattern created on a target portion of a substrate. The term "light valve" can also be used in this context. Examples of such patterning devices other than classical masks (transmission or reflection masks, binary masks, phase-shift masks, hybrid masks, etc.) include programmable mirror arrays and programmable LCD arrays.

[0023]

[0021] Figure 1 schematically illustrates 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 according to 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 according to certain parameters, and a projection system (e.g., a refractive projection lens system) PS configured to project a pattern imparted to the radiation beam B by the patterning device MA onto a target portion C (e.g., including one or more dies) of the substrate W.

[0024]

[0022] 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 may 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 its cross-section has a desired spatial and angular intensity distribution in the plane of the patterning device MA.

[0025]

[0023] As used herein, the term “projection system” PS should be interpreted broadly to encompass various types of projection systems, including refractive optical systems, reflective optical systems, reflective refractive optical systems, anamorphic optical systems, magneto-optical systems, electromagnetic optical systems, and / or electrostatic optical systems, or any combination thereof, as appropriate in accordance with the exposure radiation used and / or other factors such as the use of immersion liquid or vacuum. Where the term “projection lens” is used herein, it can be considered synonymous with the more general term “projection system” PS.

[0026]

[0024] The lithography apparatus is of a type in which at least a portion of the substrate W is covered with an immersion liquid having a relatively high refractive index, such as water, so as to fill the immersion space between the projection system PS and the substrate W, and this is also called immersion lithography. Further information on immersion technology is described in U.S. Patent No. 6,952,253, which is incorporated herein by reference.

[0027]

[0025] The lithography apparatus may be of a type that has two or more substrate support WTs (also called a “dual-stage”). In such a “multi-stage” machine, the substrate support WTs may be used in parallel, and / or, while a substrate W on one substrate support WT is being used to expose a pattern onto that substrate W, a preparation step for subsequent exposure of the substrate W may be performed on a substrate W located on another substrate support WT.

[0028]

[0026] In addition to the substrate support WT, the lithography apparatus may include a measurement stage (not shown in the drawings). The measurement stage is positioned to hold sensors and / or cleaning devices. The sensors may be positioned to measure the characteristics of the projection system PS or the characteristics of the radiating beam B. The measurement stage may hold multiple sensors. The cleaning devices may be positioned to clean parts of the lithography apparatus, such as a part of the projection system PS or a part of the system that provides the immersion fluid. The measurement stage may move below the projection system PS when the substrate support WT is away from the projection system PS.

[0029]

[0027] During operation, the radiating beam B is incident on a patterning device MA, such as a mask held on a mask support MT, and a pattern is formed by the pattern (design layout) present on the patterning device MA. The radiating beam B, having crossed the mask MA, passes through a projection system PS, which focuses the beam onto a target portion C of the substrate W. Using a second positioner PW and a position measuring system IF, the substrate support WT can be precisely moved to position various target portions C at focused and aligned positions within the path of the radiating beam B, for example. Similarly, a first positioner PM and optionally another position sensor (not explicitly shown in Figure 1) may be used to precisely position the patterning device MA relative to the path of the radiating beam B. The patterning device MA and the substrate W can be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2. The illustrated substrate alignment marks P1, P2 occupy dedicated target portions, but may also be located in the space between target portions. When substrate alignment marks P1 and P2 are located between target portions C, they are called scribe line alignment marks.

[0030]

[0028] To clarify the present invention, the Cartesian coordinate system is used. The Cartesian coordinate system has three axes, namely the x-axis, y-axis, and 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 a Ry rotation. A rotation about the z-axis is called an Rz rotation. The x-axis and y-axis define the horizontal plane, while the z-axis is perpendicular. The Cartesian coordinate system is used only for clarification and not to limit the present invention. Alternatively, another coordinate system, such as a cylindrical coordinate system, may be used to clarify the present invention. The orientation of the Cartesian coordinate system may be different, for example, such that the z-axis has a component along the horizontal plane.

[0031]

[0029] Immersion technology has been introduced into lithography systems to enable improved resolution of smaller features. In an immersion lithography apparatus, a liquid layer of immersion fluid having a relatively high refractive index is interposed in the immersion space between the apparatus's projection system PS (the patterned beam is projected through the projection system PS toward the substrate W) and the substrate W. The immersion fluid covers at least the portion of the substrate W below the final element of the projection system PS. Thus, at least the portion of the substrate W that is exposed is immersed in the immersion fluid.

[0032]

[0030] In commercial immersion lithography, the immersion fluid is water. Typically, the water is highly purified distilled water, such as ultrapure water (UPW), which is commonly used in semiconductor manufacturing plants. In immersion systems, UPW is often purified and may undergo additional processing steps before being supplied to the immersion space as the immersion fluid. In addition to water, other liquids with a high refractive index, such as hydrocarbons including fluorinated hydrocarbons, and / or aqueous solutions, can be used as the immersion fluid. It is also conceivable that other fluids other than liquids may be used in immersion lithography.

[0033]

[0031] In this specification, local immersion refers to a situation in which, during use, the immersion fluid is confined to an immersion space between the final element and the surface facing the final element. This opposing surface is the surface of the substrate W, or the surface of a support stage (or substrate support WT) that is coplanar with the surface of the substrate W (note that when the surface of the substrate W is referred to below, unless otherwise specified, the surface of the substrate support WT is also referred to, and vice versa). A fluid handling structure IH located between the projection system PS and the substrate support WT is used to confine the immersion fluid to the immersion space. The immersion space, filled with the immersion fluid, is smaller than the top surface of the substrate W when viewed from above, and the immersion space remains substantially stationary relative to the projection system PS while the substrate W and substrate support WT move below.

[0034]

[0032] Other immersion systems are also envisioned, such as non-confined immersion systems (so-called "all-wet" immersion systems) and tank immersion systems. In non-confined immersion systems, the immersion liquid covers more than the surface beneath the final element. The liquid outside the immersion space exists as a thin liquid film. The liquid can cover the entire surface of the substrate W, or even the substrate W and the substrate support WT that is coplanar with the substrate W. In tank-type systems, the substrate W is completely immersed in a tank of immersion liquid.

[0035]

[0033] A fluid handling structure IH is a structure that supplies immersion fluid to an immersion space, removes immersion fluid from the immersion space, and thereby confines immersion fluid in the immersion space. It includes features that are part of a fluid supply system. The configuration disclosed in PCT Patent Application Publication WO99 / 49504 is an early fluid handling structure that includes a pipe that supplies or retrieves immersion fluid from the immersion space and operates in accordance with the relative motion of the stage below the projection system PS. In more recent designs, the fluid handling structure extends along at least a portion of the boundary of the immersion space between the final element of the projection system PS and the substrate support WT or substrate W so as to partially define the immersion space.

[0036]

[0034] The fluid handling structure IH may have a variety of functions. Each function may be derived from a corresponding feature that enables the fluid handling structure IH to achieve that function. The fluid handling structure IH may be referred to by several different terms, each referring to a single function, such as barrier members, sealing members, fluid supply systems, fluid removal systems, and liquid containment structures.

[0037]

[0035] The immersion liquid may be used as an immersion fluid. In that case, the fluid handling structure IH may be a liquid handling system. When referring to features defined in this paragraph in accordance with the preceding description, it can be understood that these features include features defined in relation to liquids.

[0038]

[0036] The lithography apparatus has a projection system PS. During exposure of the substrate W, the projection system PS projects a beam of patterned radiation onto the substrate W. To reach the substrate W, the path of the radiation beam B is from the projection system PS 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 at the end of the beam path, which is in contact with the immersion liquid. This lens element in contact with the immersion liquid may 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 can confine the immersion liquid below and on the opposite surface of the final element.

[0039]

[0037] As shown in Figure 1, the lithography apparatus includes a controller 600. The controller 600 is configured to control the substrate support WT.

[0040]

[0038] Figure 2 shows some known lithography apparatus that do not conform to the present invention. The configuration shown in Figure 2 and described below may be applied to the lithography apparatus described above and shown in Figure 1. Figure 2 is a cross-sectional view of the substrate support 20 and the substrate W. In one embodiment, the substrate support 20 includes one or more adjustment channels 61 of a thermal conditioner. A gap 5 exists 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 other times such as when the substrate W first moves under the projection system PS (as described above), the immersion space filled with liquid by the fluid handling structure IH (for example) will pass at least partially over the gap 5 between the edge of the substrate W and the edge of the substrate support 20. This may allow the liquid to enter the gap 5 from the immersion space.

[0041]

[0039] The substrate W is held by a support 21 (e.g., a pimple or prick table) having one or more pry bars 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, i.e., vacuum, applied between the substrate W and the substrate support 20 defining the clamping area helps to ensure that the substrate W is held firmly in place by applying a clamping force. However, if immersion liquid enters between the substrate W and the support 21, it can cause problems, especially when unloading the substrate W.

[0042]

[0040] To address the ingress of immersion liquid into the gap 5, at least one drain 10, 12 is provided on the edge of the substrate W to remove the immersion liquid that enters the gap 5. In the embodiment shown in Figure 2, two drains 10, 12 are shown, but there may be only one drain or there may be three or more drains. In one embodiment, each of the drains 10, 12 is annular so as to surround the entire circumference of the substrate W.

[0043]

[0041] The primary function of the first drain 10 (radially outward from the edge of the substrate W / support 21) is to help prevent gas bubbles from entering the immersion space where the liquid of the fluid handling structure IH is present. Such bubbles can have a detrimental effect on imaging of the substrate W. The first drain 10 is present to help prevent gas in the gap 5 from escaping into the immersion space of the fluid handling structure IH. If gas escapes into the immersion space, this can cause bubbles to float in the immersion space. If such bubbles are in the path of the projection beam, it can 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 in which the substrate W is placed. The edge of the recess in the substrate support 20 may be defined by a covering 101 which is optionally separated from the support 21 of the substrate support 20. In the x / y plane, the covering 101 may be in the shape of a ring surrounding the outer edge of the substrate W. The first drain 10 extracts mostly gas, with only a small amount of immersion liquid.

[0044]

[0042] The second drain 12 (located radially inward from the edge of the substrate W / support 21) is provided to help prevent liquid advancing under the substrate W from the gap 5 from hindering the efficient release of the substrate W from the substrate support WT after imaging. Providing the second drain 12 mitigates or eliminates any problems that may arise due to liquid advancing under the substrate W.

[0045]

[0043] As shown in Figure 2, the lithography apparatus includes a first extraction channel 102 through which a two-phase flow passes. The first extraction channel 102 is formed within the block. The first and second drains 10 and 12 are provided with corresponding openings 107 and 117 and corresponding extraction channels 102 and 113, respectively. The extraction channels 102 and 113 are in fluid communication with the corresponding openings 107 and 117 through corresponding passages 103 and 114.

[0046]

[0044] As shown in Figure 2, the covering 101 has an upper surface. The upper surface extends circumferentially around the substrate W on the support 21. When the lithography apparatus is used, the substrate support 20 moves relative to the fluid handling structure IH. During this relative movement, the fluid handling structure IH passes 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 on top of 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 on top of the substrate support 20. In the following description, movement of the fluid handling structure IH is used to mean the relative movement of the substrate support 20 with respect to the fluid handling structure IH.

[0047]

[0045] Known designs of the covering 101 have a circular opening for receiving the substrate W in plan view. This opening has a fixed diameter. The diameter of this opening is designed to be larger than the diameter of the substrate W under all circumstances that can reasonably be predicted to occur. If the diameter of the opening is too small, the covering 101 may not be usable with the substrate W under all circumstances. The minimum allowable diameter of the opening is determined by the diameter of the substrate W that the covering 101 is designed to surround and the required tolerances. The required tolerances include the manufacturing tolerance of the substrate W, the manufacturing tolerance of the opening of the covering 101, and the change in the diameter of the substrate W and the opening of the covering 101 during use.

[0048]

[0046] The gap 5 between the covering 101 and the substrate W is provided by an opening having a larger diameter than the substrate W. In some places, the gap 5 may be about 200 μm. When the fluid handling structure IH passes through the gap 5, at least a portion of the immersion liquid flows through the gap 5.

[0049]

[0047] A problem with the known art is that the flow of immersion liquid through the gap 5 increases the thermal load on the substrate W and the substrate support 20. The flow of immersion liquid through the gap 5 can also generate bubbles in the immersion liquid. Bubbles can cause imaging defects, and large bubbles, which can have a diameter of up to 100 μm, are particularly problematic. Because the diameter of the opening is fixed, the average size of the gap 5 cannot be reduced. Therefore, in the known art, reducing the size of the gap 5 does not reduce the flow of immersion liquid through the gap 5.

[0050]

[0048] The embodiments improve upon known technology by providing novel coverings. In the covering according to the embodiments, the opening for receiving the substrate W has an adjustable diameter and / or shape. The covering may otherwise be substantially the same as known coverings. Before the substrate W is loaded onto the substrate support, the diameter of the opening may be substantially the same as the fixed diameter of the opening of known coverings 101. After the substrate W is loaded onto the substrate support, the diameter of the opening may be reduced to reduce the size of the gap between the covering and the substrate W.

[0051]

[0049] A cross-section of the covering 301 according to the first embodiment of the present invention is schematically shown in Figures 3A and 3B.

[0052]

[0050] Figures 3A and 3B show a cross-section of the lower part of the fluid handling structure 308. The fluid handling structure 308 may be substantially the same as the fluid handling structure IH used in the known techniques described earlier. The fluid handling structure 308 is located above the substrate W and the substrate support 300.

[0053]

[0051] The substrate W is supported by a crowbar 312 protruding from the support 310 of the substrate support 300. The crowbar 312 may be substantially the same as the crowbar 41 in the previously described known art. The support 310 may be substantially the same as the support 21 in the previously described known art. The substrate support 300 includes a fluid inlet located below the substrate W and a fluid extraction channel 309 which may be substantially the same as the fluid extraction passage 114 and / or channel 113 in the previously described known art. The substrate support 300 includes a fluid inlet located beside the substrate W and a fluid extraction channel 311 which may be substantially the same as the fluid extraction passage 103 and / or channel 102 in the previously described known art. The fluid extraction channel 311 may alternatively be connected to ambient pressure and not used for fluid extraction. The substrate support 300 includes a covering 301 surrounding the substrate W in plan view. The upper surface of the covering 301 may be substantially coplanar with the upper surface of the substrate W.

[0054]

[0052] An immersion fluid, which may contain liquid, is present in an immersion fluid region 314, which may be substantially the same as the immersion space described above. Between the substrate W and the fluid handling structure 308 is a first meniscus 307 of the immersion fluid. Between the covering 301 and the fluid handling structure 308 is a second meniscus 307 of the immersion fluid. Between the substrate W and the covering 301 is a gap 306.

[0055]

[0053] The covering 301 has a flexible structure. The flexible structure may be a bellows and / or may include a bellows. The flexible structure includes a first surface 302, a second surface 303, a third surface 304, and a fourth surface 305. There is a first corner 302a between the first surface 302 and the second surface 303. There is a second corner 303a between the second surface 303 and the third surface 304. There is a third corner 304a between the third surface 304 and the fourth surface 305. There is a fourth corner 305a between the fourth surface 305 and the body of the covering 301. The first surface 302 of the flexible structure is part of the planar top surface of the covering 301 and may have one end connected to the body of the covering 101. The second surface 303 may be the substrate-facing surface of the covering 301. The third surface 304 may be the bottom surface of the covering 301 facing away from the substrate W. The fourth surface 304 may be the bottom surface of the covering 301 facing towards the substrate W. Each of the surfaces 302, 303, 304, and 305 may have a substantially straight cross-section.

[0056]

[0054] The body and flexible structure of the covering 301 define a closed region within the covering 301. There is a fluid conduit 313 configured to supply fluid to the closed region and / or extract fluid from the closed region. The fluid may be a gas, such as air. Alternatively, the fluid may be a liquid, such as water. The fluid may be a mixture of gas and liquid.

[0057]

[0055] The flexible structure is configured such that one or more of its surfaces 302, 303, 304, 305 move in response to fluid inflow into and outflow from the enclosed region. Fluid flow into the enclosed region may increase the volume of the enclosed region and / or the fluid pressure within the enclosed region. Fluid flow out of the enclosed region may decrease the volume of the enclosed region and / or the fluid pressure within the enclosed region. The flexible structure may be the only part of the covering 301 configured to move in response to changes in volume and / or pressure within the enclosed region. This movement may be enabled by one or more of the surfaces 302, 303, 304, 305 of the flexible structure bending, stretching, and / or bending one or more of the corners 302a, 303a, 304a, 305a. This movement causes the flexible structure to change between several different states. The cross-sectional shape of the flexible structure may differ in each state. To ensure that only clearly defined shape changes occur in the flexible structure, the surfaces 302, 303, 304, and 305 of the flexible structure may have different flexities. Specifically, the second surface 303 may be more flexible than the first surface 302. The fourth surface 305 may be more flexible than the third surface 304. The second surface 303 may have substantially the same flexibility as the fourth surface 305. The first surface 302 may have substantially the same flexibility as the third surface 304.

[0058]

[0056] Figure 3A shows the flexible structure in a first state. The first state is sometimes referred to as the contracted state of the covering 301. The second corner 303a of the second surface 303 of the flexible structure is away from the substrate W. The gap 306 between the substrate W and the second surface 303 may be similar to the gap when a known covering 101 is used. Thus, the gap 306 is sufficient to load the substrate W onto the substrate support 300 and remove it from the substrate support 300, taking into account the required tolerances. The average size of the gap 306 may be greater than about 125 μm, preferably greater than 200 μm.

[0059]

[0057] Figure 3B shows the flexible structure in the second state. The second state is sometimes referred to as the expanded state of the covering 301. The second corner 303a of the second surface 303 of the flexible structure is closer to the substrate W than in the first state. Therefore, the minimum size of the gap 306 between the substrate W and the closest part of the second surface 303 is smaller than in the first state. The average size of the gap 306 may be less than approximately 35 μm, and preferably less than 5 μm.

[0060]

[0058] When the flexible structure is in the second state, the small size of the gap 306 may significantly reduce or completely prevent the flow of immersion fluid from the immersion fluid region 314 through the gap 306. Advantageously, this mitigates or avoids the problems described above that such immersion fluid flow can cause.

[0061]

[0059] When the substrate W is loaded onto the substrate support 300, the flexible structure of the covering 301 may be controlled to be in a first state. After the substrate W is loaded, the flexible structure of the covering 301 may be controlled to be in a second state to reduce the size of the gap 306. This reduces the amount of immersion fluid that can flow through the gap 306 as the fluid handling structure 308 passes over the gap 306. Before the substrate W is unloaded, the flexible structure of the covering 301 may be controlled to return to the first state.

[0062]

[0060] A cross-section of the covering 401 according to a second embodiment of the present invention is schematically shown in Figures 4A and 4B.

[0063]

[0061] A second embodiment provides a substrate support 400 with an alternative covering 401. The covering 401 of the second embodiment also comprises a closed region surrounded at least partially by a flexible structure. The flexible structure may be a bellows. The covering 401 of the second embodiment may differ from the covering 301 of the first embodiment by having a different shape for the flexible structure. The substrate support 400 and all other features shown in Figures 4A and 4B may otherwise be the same as those described in the first embodiment.

[0064]

[0062] In the second embodiment, the flexible structure comprises a first surface 402, a second surface 403, a third surface 404, and a fourth surface 405. There is a first corner 402a between the first surface 402 and the second surface 403. There is a second corner 403a between the second surface 403 and the third surface 404. There is a third corner 404a between the third surface 404 and the fourth surface 405. There is a fourth corner 405a between the fourth surface 405 and the body of the covering 401. The first surface 402 of the flexible structure is part of the upper surface of the covering 401 and may have one end connected to the body of the covering 401. The second surface 403 may be the substrate-facing surface of the covering 401. The third surface 404 may be the lower surface of the covering 401 facing in the opposite direction to the first surface 402. The fourth surface 404 may be the underside of the covering 401 facing the substrate W. Each surface 402, 403, 404, and 405 may have a substantially straight cross-section.

[0065]

[0063] The body and flexible structure of the covering 401 define a closed region within the covering 401. There is a fluid conduit 406 configured to supply fluid to the closed region and / or extract fluid from the closed region. The fluid may be a gas, such as air. Alternatively, the fluid may be a liquid, such as water. The fluid may be a mixture of gas and liquid.

[0066]

[0064] As described in the first embodiment, the flexible structure is configured to change shape in response to fluid inflow into and outflow from the enclosed region. The flexible structure may be the only part of the covering 401 configured to move in response to changes in volume and / or pressure within the enclosed region. This movement may be enabled by one or more of the surfaces 402, 403, 404, 405 of the flexible structure bending, stretching, and / or bending one or more of the corners 402a, 403a, 404a, 405a. This movement causes the flexible structure to change between several different states. The shape of the flexible structure may differ in each state. To ensure that only clearly defined shape changes of the flexible structure occur, the surfaces 402, 403, 404, 405 of the flexible structure may each have different flexibility. Specifically, the second surface 403 may be more flexible than the first surface 402. The fourth surface 405 may be more flexible than the third surface 404. The second surface 403 may have substantially the same flexibility as the fourth surface 405. The first surface 402 may have substantially the same flexibility as the third surface 404.

[0067]

[0065] Figure 4A shows the flexible structure in a first state. The first state is sometimes referred to as the contracted state of the covering 401. The second corner 403a of the second surface 403 of the flexible structure is away from the substrate W. The gap 306 between the substrate W and the second surface 403 may be similar to the gap when a known covering 101 is used. Thus, the gap 306 is sufficient to load the substrate W onto the substrate support 400 and remove it from the substrate support 400, taking into account the required tolerances. The average size of the gap 306 may be greater than about 125 μm, preferably greater than 200 μm.

[0068]

[0066] Figure 4B shows the flexible structure in the second state. The second state is sometimes referred to as the expanded state of the covering 401. The second corner 403a of the second surface 403 of the flexible structure is closer to the substrate W than in the first state. Therefore, the minimum size of the gap 306 between the substrate W and the closest part of the second surface 403 is smaller than in the first state. The average size of the gap 306 may be less than about 35 μm, preferably less than 5 μm.

[0069]

[0067] The covering 401 of the second embodiment has the same or the same advantages as those previously described for the covering 301 of the first embodiment.

[0070]

[0068] When the substrate W is loaded onto the substrate support 400, the flexible structure of the covering 401 may be controlled to be in a first state. After the substrate W is loaded, the flexible structure of the covering 401 may be controlled to be in a second state to reduce the size of the gap 306. This reduces the amount of immersion fluid that can flow through the gap 306 as the fluid handling structure 308 passes over the gap 306. Before the substrate W is unloaded, the flexible structure of the covering 401 may be controlled to return to the first state.

[0071]

[0069] In the second embodiment, the third surface 404 of the covering 401 remains substantially parallel to the upper surface of the support 310 when transitioning between different states. Therefore, the shape of the flexible structure reduces the risk of fluids such as air and / or water being trapped in this region. If fluid is trapped in this region, the movement of the flexible structure may cause undesirable pressure changes. This is an advantage over the first embodiment, where there is a high risk of fluid being trapped in the corresponding region between the lower surface of the flexible structure and the upper surface of the support 310. Another advantage over the first embodiment is that the volume of the region between the lower surfaces 404, 405 of the covering 401 and the support 310 does not substantially change when the flexible structure moves.

[0072]

[0070] A cross-section of the covering 501 according to a third embodiment of the present invention is schematically shown in Figures 5A and 5B.

[0073]

[0071] A third embodiment provides a substrate support 500 with an alternative covering 501. The covering 501 of the third embodiment also comprises a closed region surrounded at least partially by a flexible structure. The flexible structure may be a bellows. The covering 501 of the third embodiment may differ from the coverings 301, 401 of the first or second embodiment by having a different shape for the flexible structure. The substrate support 500 and all other features shown in Figures 5A and 5B may otherwise be the same as those described in the first or second embodiment.

[0074]

[0072] In the third embodiment, the flexible structure comprises a first surface 502, a second surface 503, a third surface 504, a fourth surface 505, and a fifth surface 506. A first corner 502a is located between the first surface 502 and the second surface 503. A second corner 503a is located between the second surface 503 and the third surface 504. A third corner 504a is located between the third surface 504 and the fourth surface 505. A fourth corner 505a is located between the fourth surface 505 and the fifth surface 506. A fifth corner 506a is located between the fifth surface 506 and the body of the covering 501. The first surface 502 of the flexible structure is part of the upper surface of the covering 501 and may have one end connected to the body of the covering 501. The second surface 503 may be the substrate-facing surface of the covering 501. The third surface 504 may be the bottom surface of the covering 501 facing in the opposite direction to the first surface 502. The fourth surface 505 may be the bottom surface of the covering 501 facing away from the substrate W. The fifth surface 506 may be the bottom surface of the covering 501 facing towards the substrate W. Each of the surfaces 502, 503, 504, 505, and 506 may have a substantially straight cross-section.

[0075]

[0073] The body and flexible structure of the covering 501 define a closed region within the covering 501. There is a fluid conduit 507 configured to supply fluid to the closed region and / or extract fluid from the closed region. The fluid may be a gas, such as air. Alternatively, the fluid may be a liquid, such as water. The fluid may be a mixture of gas and liquid.

[0076]

[0074] As described in the first or second embodiment, the flexible structure is configured to change shape in response to fluid inflow into and outflow from the enclosed region. The flexible structure may be the only part of the covering 501 configured to move in response to changes in volume and / or pressure within the enclosed region. This movement may be enabled by one or more of the surfaces 502, 503, 504, 505, 506 of the flexible structure bending, stretching, and / or bending one or more of the corners 502a, 503a, 504a, 505a, 506a. This movement causes the flexible structure to change between several different states. The shape of the flexible structure may differ in each state. To ensure that only clearly defined shape changes of the flexible structure occur, the surfaces 502, 503, 504, 505, 506 of the flexible structure may have different flexibility. Specifically, the second surface 503 may be more flexible than the first surface 502. The fourth surface 505 may be more flexible than the third surface 504. The second surface 503 may have substantially the same flexibility as the fourth surface 505. The first surface 502 may have substantially the same flexibility as the third surface 504.

[0077]

[0075] Figure 5A shows the flexible structure in a first state. The first state is sometimes referred to as the contracted state of the covering 501. The second corner 503a of the second surface 503 of the flexible structure is away from the substrate W. The gap 306 between the substrate W and the second surface 503 may be similar to the gap when a known covering 101 is used. Thus, the gap 306 is sufficient to load the substrate onto the substrate support 500 and remove it from the substrate support 500, taking into account the required tolerances. The average size of the gap 306 may be greater than about 125 μm, preferably greater than 200 μm.

[0078]

[0076] Figure 5B shows the flexible structure in the second state. The second state is sometimes referred to as the expanded state of the covering 501. The second corner 503a of the second surface 503 of the flexible structure is closer to the substrate W than in the first state. Therefore, the minimum size of the gap 306 between the substrate W and the closest part of the second surface 503 is smaller than in the first state. The average size of the gap 306 may be less than about 35 μm, and preferably less than 5 μm.

[0079]

[0077] The covering 501 of the third embodiment has the same or the same advantages as those previously described for the covering 301 of the first embodiment and / or the second embodiment.

[0080]

[0078] When the substrate W is loaded onto the substrate support 500, the flexible structure of the covering 501 may be controlled to be in a first state. After the substrate W is loaded, the flexible structure of the covering 501 may be controlled to be in a second state to reduce the size of the gap 306. This reduces the amount of immersion fluid that can flow through the gap 306 as the fluid handling structure 308 passes over the gap 306. Before the substrate W is unloaded, the flexible structure of the covering 501 may be controlled to return to the first state.

[0081]

[0079] In the third embodiment, the length of the fourth surface 505 and the fifth surface 506 is relatively long, which may facilitate the shape change of the flexible structure. This may be an advantage over the second embodiment, in which relatively high stress may be generated on the fourth surface 405.

[0082]

[0080] A cross-section of the covering 301 according to the fourth embodiment of the present invention is schematically shown in Figures 6A and 6B.

[0083]

[0081] A fourth embodiment provides a substrate support 300 with another alternative covering 301. The covering 301 of the fourth embodiment may include a flexible cover 601. The substrate support 300 of the fourth embodiment may otherwise be the same as the substrate support 300 described earlier for the first embodiment.

[0084]

[0082] The flexible cover 601 may be a flexible solid material such as a polymer. Alternatively, the flexible cover 601 may be an elastic band with one end fixed to or near the second corner 303a and the other end fixed to or near the fourth corner 305a. The purpose of the flexible cover 601 is to prevent fluids such as air and / or water from being trapped in the region between the lower surface of the flexible structure and the upper surface of the support 310. This can reduce undesirable pressure changes caused by the movement of the flexible structure.

[0085]

[0083] In all of the first to fourth embodiments, the neutral state of the flexible structure may be defined as being near or in the center of its range of motion as the fluid enters and exits the enclosed region. The flexible structure may be designed so that its neutral state is near or in the intermediate position between the first and second states. Thus, the flexible structure may contract from the neutral state to transition to the first state and expand from the neutral state to transition to the second state. This ensures efficient use of the range of motion of the flexible structure.

[0086]

[0084] The first state of the flexible structure may be a predetermined position of the flexible structure which can be used with almost all or all substrates W. In the first state, the diameter of the opening for receiving the substrate W in the flexible structure may be substantially the same as the opening for receiving the substrate W in a known covering 101.

[0087]

[0085] When the flexible structure is in the first state and the substrate W is loaded onto the substrate supports 300, 400, 500, the size of the gap 306 may change along the perimeter of the substrate W. The change in the size of the gap 306 may be caused by inaccuracies in the positioning of the substrate W. Further causes of the change may include changes in the diameter of the substrate W or changes in the shape of the flexible structure.

[0088]

[0086] The shape of the flexible structure in the second state may be determined by the minimum size of the gap 306 along the perimeter of the substrate 306. When changing from the first state to the second state, the flexible structure may be moved until the minimum size of the gap 306 is less than about 35 μm, preferably less than about 5 μm, and more preferably less than about 3 μm. Preferably, in the second state, the flexible structure does not contact the substrate W. However, embodiments also include the flexible structure contacting the substrate W. The advantage of the flexible structure contacting the substrate W is that it can completely close the gap 306 and prevent fluid flow through the gap 306. However, contact can result in a force being applied from the flexible structure to the substrate W, which may cause a local position change of the substrate W. Nevertheless, if the rigidity of the flexible structure is low and the force applied by contact with the flexible structure is small, the local position change of the substrate W may not be significant.

[0089]

[0087] In order to determine the second state of the flexible structure, the diameter and roundness of the substrate W may be determined. The position of the substrate W on the substrate supports 300, 400, and 500 may also be determined when the substrate W is loaded onto the substrate supports 300, 400, and 500. By determining the roundness and position of the substrate, the size of the gap 306 around the substrate W when the flexible structure is in the first state can be determined. Next, the second state of the flexible structure may be determined depending on the determined size of the gap 306 around the substrate W. Next, the flexible structure may transition to the second state by the inflow of fluid into the closed region, which increases the pressure within the closed region. The amount of fluid flow used to move the flexible structure may be determined depending on the expected movement of the flexible structure in response to the fluid flow.

[0090]

[0088] In all of the first to fourth embodiments, the flexible structure is described as having multiple surfaces. These surfaces are the outer surfaces of each wall of the enclosed region. Each wall of the enclosed region may be made separately from each other and then joined together.

[0091]

[0089] The material of the flexible structure is preferably resistant to DUV radiation irradiating the substrate. The flexible structure may be made of, for example, titanium, spring steel, or nickel. One or more of the outer surfaces of the flexible structure may be coated. The coating may help to control the flow of the immersion fluid.

[0092]

[0090] The material of the remaining parts of the substrate supports 300, 400, and 500 is not particularly limited and may be any suitable material known in the art. Preferably, the substrate supports 300, 400, and 500 may be made of silicon-impregnated silicon carbide (SiSiC). Alternatively, the substrate supports 300, 400, and 500 may be formed of Zerodur® (lithium aluminosilicate glass ceramic), cordierite, silicon carbide (SiC), or diamond SiSiC.

[0093]

[0091] The radial stroke of the flexible structure, i.e., the maximum change in the radius of the opening of the flexible structure, may be about 100 μm. The operating pressure range in the closed region may range from -0.5 barg to 0.5 barg. The applied material stress may be less than 275 MPa. Coverings 301, 401, and 501 according to the embodiment may have the same volume as the known covering 101. The wall thickness of the flexible structure may be about 10 μm or less. The vertical stiffness of the flexible structure may be greater than about 4E5 N / m. The radial stiffness of the flexible structure may be greater than about 1E5 N / m.

[0094]

[0092] Figures 7A and 7B are schematic plan views of the covering 700 according to the fifth embodiment. The covering 700 provides the upper surface of the substrate support (not shown).

[0095]

[0093] The covering 700 includes an aperture mechanism 701 having an opening for receiving the substrate W. The aperture mechanism 701 includes a plurality of segments 703a to h. Although eight segments 703a to h are shown in Figures 7A and 7B, embodiments include aperture mechanisms having more or fewer segments 703a to h. Each segment 703a to h may be in direct contact with two other segments 703a to h. The contact surface between two adjacent segments 703a to h is the curved side surface of the segments 703a to h. The side surface of each segment 703a to h may have a depth which may be the thickness of each segment 703a to h in a direction perpendicular to the planar top and / or bottom surface of each segment 703a to h. The width of each segment 703a to h may be defined in a plane parallel to the planar top and / or bottom surface of each segment. The width of each segment 703a to h is maximum at the outer periphery of the aperture mechanism 701 and may gradually narrow to a minimum in an inward spiral direction parallel to the planar upper and / or lower surfaces of each segment 703a to h. The upper surfaces of each segment 703a to h may be substantially coplanar with each other and with the upper surface of the substrate W.

[0096]

[0094] Figures 7A and 7B show a substrate W loaded onto a substrate support. As previously described, the substrate W may be supported by the bar of the substrate support. The substrate W is located within the opening of the aperture mechanism 701. There is a gap 702 between the inner surface of the aperture mechanism 701 and the substrate W. Segments 703a to h of the aperture mechanism 701 are arranged to move relative to each other in order to change the size of the gap 702.

[0097]

[0095] Figure 7A shows the aperture mechanism 701 in a first state. In the first state, the diameter of the opening is as previously described for the first state of the flexible structure in the first to fourth embodiments. That is, the diameter of the opening is large enough to accommodate almost all of the substrate W, taking tolerances into consideration.

[0098]

[0096] Figure 7B shows the aperture mechanism 701 in a second state. In the second state, the diameter of the opening is as previously described for the second state of the flexible structure in the first to fourth embodiments. That is, the diameter of the opening is reduced to reduce, and in some cases to obstruct, the flow of immersion fluid through the gap 702 as the fluid handling structure IH passes over the gap 702.

[0099]

[0097] In order to change between the first state and the second state, the contact surfaces of segments 703a to h may slide relative to each other. The movement of each segment 703a to h may include at least a partial rotation about the center point of the opening. The aperture mechanism 701 may include an actuation system (not shown) configured to move each of the segments 703a to h. The actuation system may include one or more piezoelectric actuators, one or more pneumatic actuators, and / or one or more hydraulic actuators. The actuation system may be configured so that all of the segments 703a to h move substantially the same amount simultaneously. However, embodiments also include the fact that the movement of two or more segments 703a to h is independently controllable. This allows some of the segments 703a to h to move by different amounts. This allows the shape of the opening to be appropriately modified to account for positioning errors and roundness errors of the substrate W. Modifying the shape of the opening may reduce the change in the size of the gap 702 along the perimeter of the substrate W. When the aperture mechanism 701 is in the second state, the average minimum size of the gap 702 may also decrease. Embodiments also include moving segments 703a-h to reduce the gap 702 only in the area covered by the fluid handling structure IH of the covering 700, or to close it completely. The movement of segments 703a-h required to reach the second state may be determined in the same way as described for flexible structures in other embodiments.

[0100]

[0098] In one embodiment, one or more surfaces of each segment 703a to h may have a plurality of openings (not shown), and these surfaces are sieve-like. Preferably, the diameter of all openings is large enough so that the sieve-like surface can permeate the gas. Preferably, the diameter of the openings is too small for substantial liquid flow to exist through the openings. Advantageously, the use of openings reduces the weight of segments 703a to h.

[0101]

[0099] One or more surfaces of each segment 703a to h may be coated. For example, the upper surface of each segment 703a to h may be coated with either a hydrophobic or hydrophilic coating. The lower surface of each segment 703a to h may be coated with a hydrophobic coating to prevent droplets from remaining on these lower surfaces. This may also reduce the sliding resistance when adjacent segments 703a to h move relative to each other. The coating on the upper surface of each segment 703a to h may be called the first coating. The coating on the lower surface of each segment 703a to h may be called the second coating. The first and second coatings may be different from each other.

[0102]

[0100] Embodiments include the aperture mechanism 701 being in a first state when the substrate W is being loaded and unloaded. The aperture mechanism 701 may be moved to be in a second state most of the time. Embodiments also include, alternatively, the aperture mechanism 701 transitioning to the second state only when the fluid handling structure IH is near and / or passing over the gap 702. The aperture mechanism 701 may be in the first state most of the time.

[0103]

[0101] Each of segments 703a to h may be made (at least in part) of a metal, such as titanium or stainless steel, a ceramic material, or a polymer.

[0104]

[0102] Embodiments include several modifications and variations of the above-described technology.

[0105]

[0103] In the first to fourth embodiments described above, the flexible structure is a single annular structure. Embodiments also include flexible structures having multiple segments. The segments are arranged around the opening, and each segment may provide a different portion around the annular flexible structure. The number of segments may be, for example, 10, or any other appropriate number. Each segment may include a closed region and a fluid conduit to the closed region. This may allow the movement of each segment to be controlled independently of the movement of the other segments. Each segment may be configured to change between at least the first and second states described above in response to fluid inflow into and outflow from the closed region. If the fluid inflow and outflow to the segments are all controlled simultaneously and in the same way as to each other, the flexible structure may respond in substantially the same way as described in the first to fourth embodiments. However, the fluid inflow and outflow to the segments may also be controlled in different ways, resulting in one or more segments moving more than one or more of the other segments. This makes it possible to appropriately change the shape of the opening of the flexible structure to account for positioning errors and roundness errors of the substrate W. Advantageously, by changing the shape of the opening, the change in the size of the gap 306 along the perimeter of the substrate W may be reduced. In the second state of the flexible structure, the average size of the gap 306 may also be reduced. Therefore, both the cross-sectional and planar shapes of the flexible structure may be changed by the inflow and outflow of fluid to and from the segment.

[0106]

[0104] The first to fourth embodiments and their variations also include other techniques for determining the second state into which the flexible structure is transitioned. For example, the substrate supports 300, 400, and 500 may be equipped with sensors (not shown) for directly measuring the size of the gap 306 and controlling the movement of the flexible structure depending on the measured size of the gap 306. These sensors may be, for example, capacitive sensors or optical sensors.

[0107]

[0105] In the first to fourth embodiments described above, and their variations, it is preferable that at least the first corners 302a, 402a, and 502a have a smooth curvature. That is, the first corners 302a, 402a, and 502a have a defined smooth shape / radius curvature. The smooth curvature of the first corners 302a, 402a, and 502a reduces turbulence and fixation of the immersion liquid flow beyond the first corners 302a, 402a, and 502a. This may result in clearer suction, reduced liquid loss, and reduced bubble generation.

[0108]

[0106] In the first to fourth embodiments described above, and their variations, at least the top surfaces 302, 402, 502 and the substrate-facing surfaces 303, 403, 503 of each flexible structure may be adapted to facilitate the flow of liquids and moisture toward the flexible structure and their absorption therein. This adaptation may include unidirectional roughness or micrometer-level patterns.

[0109]

[0107] In the first to fourth embodiments, there is one fluid conduit 313, 406, 507 for the inflow and outflow of fluid into the enclosed region. Embodiments also include the use of separate conduits for the inflow and outflow of fluid into the enclosed region.

[0110]

[0108] The first to fourth embodiments and their variations also include other techniques for moving the flexible structure. For example, the flexible structure may be moved by one or more piezoelectric actuators, or the flexible structure may include a shape memory alloy.

[0111]

[0109] In the first to fourth embodiments and their variations, the flexible structure may be transitioned to the second state only when the fluid handling structure IH is near and / or passing over the gap 306. The flexible structure may otherwise be in the first state.

[0112]

[0110] In all embodiments, the movement of the coverings 301, 401, 501, 700 to change the diameter of the openings may be automatically controlled by a control system (not shown). The control system may be the same as the controller 600 configured to control the substrate support WT. An actuator (not shown) may be provided, configured to communicate with the control system (or controller). The actuator may drive the covering directly or indirectly to change between a first state and a second state.

[0113]

[0111] Embodiments also include different mounting configurations of the support 310 of the substrate supports 300, 400, and 500. As shown below, embodiments include support 310 that provide fluid flow to the clamping region at the edge of the substrate W. Fluid flow may locally reduce the clamping force at the edge of the substrate W, thereby reducing deformation of the substrate W. Fluid flow may also reduce the risk of unintended contact between the flexible structure and the substrate W.

[0114]

[0112] Figure 8 is a schematic cross-sectional view of another embodiment of the support 310 of the substrate support 400. The support 310 in Figure 8 is a different mounting configuration of the support 310 of the substrate support 400 of the second embodiment. The support 310 further comprises a ventilation groove 801 and one or more ventilation conduits 802. The substrate support 400 may otherwise be substantially the same as that of the second embodiment.

[0115]

[0113] In plan view, the ventilation groove 801 may be an annular groove on the substrate-facing surface of the support 310. In plan view, the annular ventilation groove 801 may extend along the entire circumference of the substrate W and be close to the edge of the substrate W. One or more ventilation conduits 802 are each configured to supply fluid to the same region in which the ventilation groove 801, and by extension the fluid extraction channel 311, is configured to extract fluid. The fluid supplied by each ventilation conduit 802 may be, for example, air or another suitable gas. There may be multiple ventilation conduits 802 within the annular ventilation groove 801 that are radially spaced apart. The number of ventilation conduits 802 may be, for example, three. Although not shown in Figure 8, there may be a valve system configured to control the flow rate of fluid through each ventilation conduit 802.

[0116]

[0114] The substrate W is held to the support 310 by a negative pressure, i.e., a vacuum, on the underside of the substrate W, which applies a clamping force to the substrate W. The negative pressure generated by the vacuum may cause the edges of the substrate W to curl toward the support 310. This curling of the edges of the substrate W is a deformation of the substrate W that can increase manufacturing tolerances.

[0117]

[0115] Embodiments include supplying a fluid flow, such as an airflow, to the ventilation groove 801 via one or more ventilation conduits 802. This fluid flow may locally reduce the negative pressure generated by the vacuum around the substrate W so that the clamping force at the edges of the substrate W is reduced. Advantageously, this may prevent or reduce curling at the edges of the substrate W, thereby reducing errors caused by such shape deformation. A further advantage of the fluid flow to the ventilation groove 801 is that it may prevent or reduce the risk of the gap 306 closing unintentionally. If the gap 306 closes unintentionally, the flexible structure will come into contact with the substrate W. Such contact may alter the shape of the substrate W, thereby causing shape deformation errors. Contact may also damage the substrate W and / or the flexible structure.

[0118]

[0116] Embodiments include the above-described ventilation grooves 801 and ventilation conduits 802 used in any of the substrate supports 300, 400, 500 of all embodiments described throughout this specification.

[0119]

[0117] The fluid flow into the ventilation groove 801 may be automatically controlled by a control system (not shown). This control system may be the same control system that controls the movement of the openings in the coverings 301, 401, 501, and 700.

[0120]

[0118] The embodiments include the following numbered clauses: 1. A covering for use as a support for a circuit board, A flexible structure having an opening for receiving a substrate, The enclosed area within the covering, A fluid conduit configured to supply fluid to and / or receive fluid from a closed region, The flexible structure is configured to change between a first state and a second state in response to fluid inflow into or outflow from a closed region. A covering in which, in the first state, the diameter of the opening is larger than in the second state. 2. The covering according to Clause 1, wherein the flexible structure is configured to change from a first state to a second state in response to fluid inflow into a closed region. 3. The covering according to Clause 1 or 2, wherein the flexible structure is configured to change from a second state to a first state in response to fluid outflow from a closed region. 4. Coverings described in any of clauses 1 to 3, in which the fluid includes air. 5. Coverings as described in any of clauses 1 to 4, wherein the cross-sectional shape in the first state of the flexible structure is different from the cross-sectional shape in the second state of the flexible structure. 6. A covering as described in any of clauses 1 to 5, wherein the flexible structure includes bellows. 7. Coverings as described in any of Clauses 1 to 6, wherein the neutral state of the flexible structure is between the first and second states. 8. The covering according to any one of the clauses 1 to 7, wherein a substrate is present in the opening of the flexible structure, and when the flexible structure is in the first state, the average distance between the outer surface of the substrate and the inner surface of the flexible structure is greater than about 125 μm, preferably about 200 μm. 9. The covering according to any one of the clauses 1 to 8, wherein a substrate is present in the opening of the flexible structure, and when the flexible structure is in the second state, the average distance between the outer surface of the substrate and the inner surface of the flexible structure is less than about 35 μm, preferably less than about 5 μm. 10. The flexible structure comprises multiple segments arranged around the opening, Each segment is configured to have a closed region and to change between a first state and a second state in response to fluid inflow into or outflow from the closed region. A covering according to any one of the clauses 1 to 9, wherein the flow of fluid into multiple enclosed regions can be independently controlled to change the shape and / or diameter of the opening. 11. A cross-section of a part of the flexible structure, A first surface for providing the top surface of the covering, A second surface for providing a substrate-facing surface for the covering, Including a corner between the first surface and the second surface, The covering is configured such that the first surface and / or the second surface bend and / or stretch when the covering changes between the first state and the second state, and / or A covering according to any of the clauses 1 to 10, wherein the second surface is configured to bend at the corners. 12. Covering as described in Clause 11, wherein the corners have a smooth curvature. 13. The corner between the first surface and the second surface is the first corner, and a cross-section of a part of the flexible structure is further, A third surface for providing the underside of the covering facing away from the second surface, A fourth surface for providing the underside of the covering facing the third surface, The second corner between the second surface and the third surface, The third corner between the third surface and the fourth surface, Including a fourth corner which is the connection point between the fourth surface and the body of the covering, The covering is configured such that when it changes between a first state and a second state, the third surface and / or the fourth surface bend and / or stretch, and / or The third surface is configured to curve at the third corner, and / or The covering according to clause 11 or 12, wherein the fourth surface is configured to curve at the fourth corner. 14. The covering according to Clause 13, further comprising a flexible cover configured to substantially close off an area enclosed by the third surface, the fourth surface and the outer surface of the flexible cover. 15. The corner between the first surface and the second surface is the first corner, and a cross-section of a part of the flexible structure is further, A third surface to provide a lower surface of the covering facing in the opposite direction to the first surface, A fourth surface to provide a lower surface of the covering facing the same direction as the second surface, The second corner between the second surface and the third surface, The third corner between the third surface and the fourth surface, Including a fourth corner which is the connection point between the fourth surface and the body of the covering, The covering is configured such that when it changes between a first state and a second state, the third surface and / or the fourth surface bend and / or stretch, and / or The third surface is configured to curve at the third corner, and / or The covering according to clause 11 or 12, wherein the fourth surface is configured to curve at the fourth corner. 16. The corner between the first surface and the second surface is the first corner, and a cross-section of a part of the flexible structure is further, A third surface to provide a lower surface of the covering facing in the opposite direction to the first surface, A fourth surface to provide a lower surface of the covering facing in the opposite direction to the second surface, A fifth surface for providing the underside of the covering facing the fourth surface, The second corner between the second surface and the third surface, The third corner between the third surface and the fourth surface, The fourth corner between the fourth surface and the fifth surface, Including a fifth corner which is the connection point between the fifth surface and the body of the covering, The covering is configured such that when it changes between a first state and a second state, the third surface, the fourth surface and / or the fifth surface bends and / or stretches, and / or The third surface is configured to curve at the third corner, and / or The fourth surface is configured to bend at the fourth corner, and / or The covering according to clause 11 or 12, wherein the fifth surface is configured to curve at the fifth corner. 17. A covering according to any of the clauses 13 to 16, wherein the fourth surface is more flexible than the third surface. 18. A covering according to any one of the clauses 11 to 17, wherein the second surface is more flexible than the first surface. 19. Coverings as described in any of clauses 11 to 18, wherein the neutral state of each surface of the flexible structure is substantially straight. 20. A substrate support configured to support a substrate, Covering as set out in any of clauses 1 through 19, A support, comprising, The support is The annular ventilation groove on the opposing surface of the substrate, A fluid supply configured to supply fluid to a ventilation groove, A circuit board support equipped with the following features. 21. A substrate support as described in Clause 20, wherein the fluid supply is configured to supply air to the ventilation groove. 22. A substrate support according to Clause 20 or 21, wherein, when the substrate is supported by the substrate support, the ventilation groove is located at or near the edge of the substrate in a plan view. 23. A lithography apparatus equipped with a substrate support as described in any of clauses 20 to 22. 24. Lithography apparatus according to Clause 23, further comprising a control system configured to control the state of a flexible structure so as to change the diameter and / or shape of an opening for a substrate. 25. Lithography apparatus according to Clause 24, wherein the control system is configured to control the state of the flexible structure according to a determined diameter and / or shape of the substrate within the opening. 26. The lithography apparatus according to Clause 24 or 25, wherein the control system is configured to control the state of a flexible structure according to the relative position of a substrate loaded onto a substrate support with respect to a fluid handling structure of the lithography apparatus used to project a radiation beam. 27. A lithography apparatus according to any one of the clauses 23 to 26, wherein the lithography apparatus is configured to perform immersion lithography. 28. A lithography apparatus according to any one of the clauses 23 to 27, wherein the lithography apparatus is a DUV lithography apparatus. 29. A method for supporting a substrate, comprising the use of a substrate support as described in any of the clauses 20 to 22. 30. A method for performing lithography, comprising projecting a radiation beam onto a substrate in an exposure operation, A method by which a substrate is supported by a substrate support as described in any of clauses 20 to 22. 31. The method according to clause 30, further comprising controlling the covering state of the substrate support according to the position of the substrate relative to a fluid handling structure used to project a radiation beam. 32. A covering for use as a support for a circuit board, It is equipped with an aperture mechanism having an opening for receiving a substrate, A covering comprising a plurality of curved segments configured to move in a direction that rotates at least partially around the center point of an opening, thereby changing the diameter and / or shape of the opening. 33. Further comprising an actuation system configured to move the segments of the aperture mechanism, The covering according to Clause 32, wherein the operating system comprises one or more piezoelectric actuators, one or more pneumatic actuators, and / or one or more hydraulic actuators. 34. Covering as described in Clause 33, wherein the operating system is configured to move at least two segments of the aperture mechanism independently. 35. A covering according to any one of the clauses 32 to 34, wherein the movement of a segment that changes the diameter and / or shape of an opening includes the sliding of the contact surfaces of adjacent segments relative to each other. 36. A covering according to any one of the clauses 32 to 35, wherein each segment has an opening to allow gas to pass through. 37. The diameter of the opening is too small to allow a liquid to flow substantially through the opening of the covering as described in Clause 36. 38. A covering according to any one of the clauses 32 to 37, wherein the upper surface of each segment has a first coating. 39. The covering described in Clause 38, wherein the first coating is hydrophobic or hydrophilic. 40. A covering according to any one of the clauses 32 to 39, wherein the lower surface of each segment has a second coating. 41. The covering described in Clause 40, wherein the second coating is hydrophobic. 42. A substrate support configured to support a substrate, Covering as set out in any of clauses 32 to 41, A support, comprising, The support is The annular ventilation groove on the opposing surface of the substrate, A fluid supply configured to supply fluid to a ventilation groove, A circuit board support equipped with the following features. 43. A substrate support as described in Clause 42, wherein the fluid supply is configured to supply air to the ventilation groove. 44. A substrate support according to Clause 42 or 43, wherein, when the substrate is supported by the substrate support, the ventilation groove is located at or near the edge of the substrate in a plan view. 45. A lithography apparatus equipped with a substrate support as described in any of clauses 42 to 44. 46. ​​Lithography apparatus according to Clause 45, further comprising a control system configured to control the aperture mechanism to change the diameter and / or shape of the opening for the substrate. 47. Lithography apparatus according to Clause 46, wherein the control system is configured to control the state of the aperture mechanism according to a determined diameter and / or shape of the substrate within the aperture. 48. The lithography apparatus according to Clause 46 or 47, wherein the control system is configured to control the state of the aperture mechanism according to the relative position of the substrate loaded onto the substrate support with respect to the fluid handling structure of the lithography apparatus used to project a radiation beam. 49. A lithography apparatus according to any one of the clauses 45 to 48, wherein the lithography apparatus is configured to perform immersion lithography. 50. A lithography apparatus as described in any of clauses 45 to 49, wherein the lithography apparatus is a DUV lithography apparatus. 51. A method for supporting a substrate, comprising the use of a substrate support as described in any of clauses 42 to 44. 52. A method for performing lithography, comprising projecting a radiation beam onto a substrate in an exposure operation, A method by which a substrate is supported by a substrate support as described in any of clauses 42 to 44. 53. The method according to clause 52, further comprising controlling the covering state of the substrate support according to the position of the substrate relative to a fluid handling structure used to project a radiation beam.

[0121]

[0119] The present invention may provide a lithography apparatus. The lithography apparatus may have any / all of the other features or components of the lithography apparatus described above. For example, the lithography apparatus may optionally include at least one of the following: a radiation source SO, an illumination system IL, a projection system PS, a substrate support WT, etc.

[0122]

[0120] Specifically, the lithography apparatus may include a projection system PS configured to project a radiation beam B toward a region of the surface of the substrate W. The lithography apparatus may further include substrate supports 300, 400, 500 as described in any of the above embodiments and modifications.

[0123]

[0121] Although this text specifically refers to the use of lithography equipment in the manufacture of ICs, it should be understood that lithography equipment described herein may have other applications. Possible other applications include the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memory, flat panel displays, liquid crystal displays (LCDs), thin-film magnetic heads, and the like.

[0124]

[0122] Where permitted by context, embodiments of the present invention may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the present invention may also be implemented as instructions stored in a machine-readable medium that can be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium may include read-only memory (ROM), random access memory (RAM), magnetic storage media, optical storage media, flash memory devices, propagating signals of electrical, optical, acoustic or other forms (e.g., carrier waves, infrared signals, digital signals, etc.), and others. Furthermore, firmware, software, routines, and instructions may be described herein as performing specific actions. However, it should be understood that such descriptions are merely for convenience, and that such actions actually result from a computing device, processor, controller, or other device that executes the firmware, software, routines, instructions, etc., and that in execution, actuators or other devices may interact with the material world.

[0125]

[0123] Although embodiments of the present invention are referred to in the context of lithography apparatus in this text, embodiments of the present invention may be used in other apparatuses. Embodiments of the present invention may form part of a mask inspection apparatus, a metrology apparatus, or any apparatus for measuring or processing objects such as wafers (or other substrates) or masks (or other patterning devices). These apparatuses may generally be referred to as lithography tools.

[0126]

[0124] Although the above has specifically referred to the use of embodiments of the present invention in the context of photolithography, it will be understood that the present invention is not limited to photolithography where permitted in the context.

[0127]

[0125] Although specific embodiments of the present invention have been described above, it will be understood that the present invention can be implemented in ways other than those described. The above description is for illustrative purposes only and is not limiting. Accordingly, it will be apparent to those skilled in the art that modifications to the described invention can be made without departing from the following claims.

Claims

1. A covering for use as a circuit board support, A flexible structure having an opening for receiving a substrate, The closed region within the covering, A fluid conduit configured to supply fluid to the closed region and / or receive fluid from the closed region, The flexible structure is configured to change between a first state and a second state in response to fluid inflow into or outflow from the closed region. A covering in which, in the first state, the diameter of the opening is larger than in the second state.

2. The flexible structure is configured to change from the first state to the second state in response to fluid inflow into the closed region, and / or The covering according to claim 1, wherein the flexible structure is configured to change from the second state to the first state in response to fluid outflow from the closed region.

3. The fluid includes air and / or The cross-sectional shape of the flexible structure in the first state is different from the cross-sectional shape of the flexible structure in the second state, and / or The flexible structure comprises a bellows and / or The neutral state of the flexible structure is between the first state and the second state, and / or A substrate is present in the opening of the flexible structure, and when the flexible structure is in the first state, the average distance between the outer surface of the substrate and the inner surface of the flexible structure is greater than approximately 125 μm, preferably about 200 μm, and / or The covering according to claim 1 or 2, wherein a substrate is present in the opening of the flexible structure, and when the flexible structure is in the second state, the average distance between the outer surface of the substrate and the inner surface of the flexible structure is less than about 35 μm, preferably less than about 5 μm.

4. The flexible structure comprises a plurality of segments arranged around the opening, Each segment is provided with a closed region and is configured to change between a first state and a second state in response to fluid inflow into or outflow from the closed region. The fluid flow into the multiple closed regions can be independently controlled to change the shape and / or diameter of the opening, and / or A cross-section of a portion of the flexible structure includes a first surface for providing the upper surface of the covering, a second surface for providing the substrate-facing surface of the covering, and a corner between the first surface and the second surface, wherein the first surface and / or the second surface bend and / or stretch when the covering changes between the first state and the second state, and / or The covering according to any one of claims 1 to 3, wherein the second surface is configured to curve at the corner, and preferably the corner has a smooth curvature.

5. The corner between the first surface and the second surface is the first corner. The cross-section of a part of the flexible structure is further A third surface for providing the lower surface of the covering facing away from the second surface, A fourth surface for providing the lower surface of the covering facing the third surface, The second corner between the second surface and the third surface, The third corner between the third surface and the fourth surface, Including a fourth corner which is a connection between the fourth surface and the body of the covering, The covering is configured such that when it changes between the first state and the second state, the third surface and / or the fourth surface bend and / or stretch, and / or The third surface is configured to bend at the third corner, and / or The fourth surface is configured to bend at the fourth corner. Or, The corner between the first surface and the second surface is the first corner. The cross-section of a part of the flexible structure is further A third surface for providing the lower surface of the covering facing in the opposite direction to the first surface, A fourth surface for providing the lower surface of the covering which faces the same direction as the second surface, The second corner between the second surface and the third surface, The third corner between the third surface and the fourth surface, Including a fourth corner which is a connection between the fourth surface and the body of the covering, The covering is configured such that when it changes between the first state and the second state, the third surface and / or the fourth surface bend and / or stretch, and / or The third surface is configured to bend at the third corner, and / or The fourth surface is configured to bend at the fourth corner. Or, The corner between the first surface and the second surface is the first corner. The cross-section of a part of the flexible structure is further A third surface for providing the lower surface of the covering facing in the opposite direction to the first surface, A fourth surface for providing the lower surface of the covering facing in the opposite direction to the second surface, A fifth surface for providing the lower surface of the covering facing the fourth surface, The second corner between the second surface and the third surface, The third corner between the third surface and the fourth surface, The fourth corner between the fourth surface and the fifth surface, Including a fifth corner which is a connection between the fifth surface and the body of the covering, The covering is configured such that when it changes between the first state and the second state, the third surface, the fourth surface and / or the fifth surface bend and / or stretch, and / or The third surface is configured to bend at the third corner, and / or The fourth surface is configured to bend at the fourth corner, and / or The covering according to claim 4, wherein the fifth surface is configured to curve at the fifth corner.

6. The covering further comprises a flexible cover configured to substantially close the area enclosed by the third surface, the fourth surface and the outer surface of the flexible cover, and / or The fourth surface is more flexible than the third surface, and / or The second surface is more flexible than the first surface, and / or The covering according to claim 5, wherein the neutral state of each surface of the flexible structure is substantially straight.

7. A substrate support configured to support a substrate, A covering according to any one of claims 1 to 6, A support, comprising, The aforementioned support is The annular ventilation groove on the opposing surface of the substrate, A fluid supply configured to supply fluid to the ventilation groove, A circuit board support equipped with the following features.

8. The fluid supply is configured to supply air to the ventilation groove, and / or The covering according to claim 7, wherein, when the substrate is supported by the substrate support, the ventilation groove is located at or near the edge of the substrate in a plan view.

9. A lithography apparatus comprising the substrate support described in claim 7 or 8.

10. The system further comprises a control system configured to control the state of the flexible structure so as to change the diameter and / or shape of the opening for the substrate, Preferably, the control system is configured to control the state of the flexible structure according to a determined diameter and / or shape of the substrate within the opening, and / or The control system is configured to control the state of the flexible structure according to the relative position of the substrate loaded onto the substrate support with respect to the fluid handling structure of the lithography apparatus used to project the radiation beam, and / or The lithography apparatus is configured to perform immersion lithography, and / or The lithography apparatus according to claim 9, wherein the lithography apparatus is a DUV lithography apparatus.

11. A method for supporting a substrate, A method comprising the use of a substrate support as described in claim 7 or 8.

12. A method for performing lithography, comprising projecting a radiation beam onto a substrate during an exposure operation, A method wherein the substrate is supported by the substrate support described in claim 7 or 8.

13. The method according to claim 12, further comprising controlling the state of the covering of the substrate support according to the position of the substrate with respect to a fluid handling structure used to project the radiation beam.

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