Substrate holder for use in lithographic equipment

Abstract

The present invention provides a substrate holder for a lithographic device and a lithographic device. The substrate holder is configured to support a substrate and includes a main body, a plurality of support elements and a sealing unit. The main body has a main body surface. A plurality of support elements protrude from the main body surface, and each support element has a distal end surface configured to support the substrate. The sealing unit may include a first sealing member, which is radially located outside the plurality of support elements and surrounds the plurality of support elements. The upper surface of the first sealing member may have a contact area configured to contact the substrate during loading and / or unloading of the substrate.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to European application 17206912.2 filed on December 13, 2017 and European application 18183119.9 filed on July 12, 2018. Both European applications are incorporated herein by reference in their entirety. Technical Field

[0003] The present invention relates to a substrate holder for use in a lithographic apparatus. Background Art

[0004] A lithographic apparatus is a machine configured to apply a desired pattern onto a substrate. For example, a lithographic apparatus may be used to manufacture integrated circuits (ICs). For example, a lithographic apparatus may project a pattern (also often referred to as a "design layout" or "design") of a patterning device (e.g., a mask) onto a layer of radiation-sensitive material (resist) disposed on a substrate (e.g., a wafer).

[0005] As semiconductor manufacturing processes continue to advance, the size of circuit elements continues to decrease, while the number of functional elements (such as transistors) per device has been steadily increasing for decades, following a trend often referred to as "Moore's Law." In order to keep up with Moore's Law, the semiconductor industry has been pursuing technologies that can create smaller and smaller features. In order to project a pattern on a substrate, a lithographic device can use electromagnetic radiation. The wavelength of this radiation determines the minimum size of the features patterned on the substrate. Typical wavelengths currently used are 365 nanometers (i-line), 248 nanometers, 193 nanometers, and 13.5 nanometers. Compared to lithographic equipment using radiation with a wavelength of, for example, 193nm, lithographic equipment using extreme ultraviolet (EUV) radiation with a wavelength in the range of 4nm to 20nm (e.g., 6.7nm or 13.5nm) can be used to form smaller features on a substrate.

[0006] In an immersion lithographic apparatus, an immersion liquid is interposed in the space between the substrate and the projection system of the apparatus. The path of this immersion liquid may reach the lower surface of the substrate from the edge of the substrate. This may be detrimental due to contamination of the lower surface of the substrate by this immersion liquid and / or thermal loads applied to the lower surface of the substrate at a location close to the edge of the substrate due to evaporation of the immersion liquid. A substrate holder configured to support the substrate may have features that reduce the amount and / or distance of radially inward movement of the immersion liquid along the lower surface of the substrate.

[0007] Typically, the substrate will be supported by a substrate holder while the substrate is being irradiated. The substrate holder may include specific parts, such as support elements, which contact the bottom of the substrate during the period of supporting the substrate. After the substrate has been irradiated, it can be removed from the substrate holder. Specific steps can be performed to unload the substrate from the substrate holder. During the process of unloading the substrate, the substrate may deform. This deformation typically causes the center of the substrate to rise away from the substrate holder, causing the substrate to hang downwardly in a cantilevered manner toward the substrate holder above the outermost holder below the substrate.

[0008] During the unloading process, the deformed substrate may come into contact with and wear against different parts of the substrate holder, which may cause various problems. First, during unloading, the interaction between the support element of the substrate holder and the underside of the substrate may cause wear of the support element. Since the support element is used to support the substrate to irradiate another layer or support another substrate, any wear of the support element may cause focusing and / or overlay problems. Wear of any support element may mean that the substrate table needs to be replaced at an appropriate time. In other words, wear of the support element may limit the service life of the substrate holder. Secondly, the bottom of the substrate tends to contact the features used to reduce the amount and / or distance of the immersion liquid moving radially inward from the outer edge. This means that the substrate will wear the features and the features will scratch against the bottom of the substrate located at the outer edge of the substrate. This will produce particles that contaminate the system and cause focusing and / or overlay problems. Summary of the invention

[0009] It is an object of the present invention to provide a substrate holder which reduces wear on support elements used to support the substrate and / or reduces damage to the underside of the substrate which could contaminate the system.

[0010] In one embodiment of the present invention, a substrate holder for use in a lithography device and configured to support a substrate is provided, the substrate holder comprising: a body having a body surface; a plurality of support elements protruding from the body surface, wherein each support element has a distal end surface configured to support the substrate and a first height; a sealing unit comprising a first sealing member protruding from the body surface, the first sealing member having an upper surface and a second height less than the first height and positioned radially outside of and surrounding the plurality of support elements, the upper surface having a contact area configured to contact the substrate during substrate loading and / or unloading; and the position of the contact area is arranged at a sufficiently sufficient distance from the plurality of support elements so that during loading and / or unloading of the substrate, the force applied by the substrate to the first sealing member is greater than the force applied by the substrate to the plurality of support elements.

[0011] In one embodiment of the present invention, a substrate holder for use in a lithography device and configured to support a substrate is provided, the substrate holder comprising: a body having a body surface; a plurality of support elements protruding from the body surface, wherein each support element has a distal end surface configured to support the substrate and a first height; a sealing unit comprising a first sealing member protruding from the body surface, the first sealing member having a second height less than the first height and positioned radially outward of and surrounding the plurality of support elements, the upper surface having a contact area configured to contact the substrate during substrate loading and / or unloading, at least one additional member protruding from the body surface and having an upper surface and having a third height less than the first height, the at least one additional member being located in the sealing unit radially outward and surrounding the plurality of support elements, the at least one additional component comprising a coating forming an upper surface of the additional component, the coating having a contact area configured to contact the substrate during loading and / or unloading of the substrate, the coating having a contact area configured to contact the substrate during loading and / or unloading of the substrate, wherein the coating is made of diamond-like carbon (e.g., a-CH), diamond, silicon carbide (e.g., SiSiC or SiC), boron nitride or boron nitride carbon (BCN); and wherein the contact area of ​​the additional component is arranged at a sufficiently sufficient distance from the plurality of support elements so that during loading and / or unloading of the substrate, the force applied by the substrate to the additional component is greater than the force applied by the substrate to the plurality of support elements.

[0012] In one embodiment of the present invention, a substrate holder for use in a lithography device and configured to support a substrate is provided, the substrate holder comprising: a body having a body surface; a plurality of support elements protruding from the body surface, wherein each support element has a distal end surface configured to support the substrate and a first height; a sealing unit comprising a first sealing member protruding from the body surface, the first sealing member having an upper surface and a second height less than the first height and positioned radially outside and surrounding the plurality of support elements, and the upper surface having a contact area configured to contact the substrate during substrate loading and / or unloading, and wherein in a cross-section radially passing through the first sealing member, a profile of the contact area has a shape configured such that during loading and / or unloading of the substrate, the substrate contacts the first sealing member via at least two different points of the profile.

[0013] In one embodiment of the present invention, a lithographic apparatus is provided, the lithographic apparatus comprising a substrate holder configured to support a substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, and in which:

[0015] - Figure 1 depicts a schematic overview of a lithography apparatus;

[0016] - Figure 2A and 2B Two different versions of a fluid handling structure are depicted in cross-section, with different features shown on the left and right, which may extend around the entire circumference;

[0017] - Figure 3A A substrate holder according to the prior art is depicted in cross section, Figure 3B Depicted Figure 3A , showing an enlarged portion of the outermost support element and the sealing member;

[0018] - Figure 4 The edge of a substrate holder according to the invention is depicted in cross section;

[0019] - Figure 5 The edge of a substrate holder according to the invention is depicted in cross section;

[0020] - Fig. 6A and 6B The edge of a substrate holder according to the invention is depicted in cross section;

[0021] - Figures 7A-7G each depicts a sealing unit according to the invention in cross section;

[0022] - Figure 8 The edge of a substrate holder according to the invention is depicted in cross section;

[0023] - Fig. 9 depicts in cross section the edge of a substrate holder according to the invention; and

[0024] - Fig.10 The edge of a substrate according to the invention is depicted in cross section. DETAILED DESCRIPTION

[0025] In this document, the terms "radiation" and "beam" are used to cover all types of electromagnetic radiation, including ultraviolet radiation (eg, having a wavelength of 365, 248, 193, 157 or 126 nm).

[0026] The terms "reticle", "mask" or "patterning device" as used herein may be broadly interpreted as referring to a general patterning device that can be used to impart a patterned cross-section to an incident radiation beam, the patterned cross-section corresponding to the pattern to be created in a target portion of the substrate. The term "light valve" may also be used in this context. In addition to classical masks (transmissive or reflective masks, binary masks, phase-shift masks, hybrid masks, etc.), other examples of such patterning devices include programmable mirror arrays and programmable LCD arrays.

[0027] Figure 1 A lithographic apparatus is schematically depicted. The lithographic apparatus comprises 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 stage) MT configured to support a patterning device (e.g., a mask) MA and connected to a first positioning device PM configured to accurately position the patterning device MA according to certain parameters, a substrate support (e.g., a wafer stage) WT configured to hold a substrate (e.g., a wafer coated with a resist) W and connected to a second positioning device 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 of the substrate W (e.g., a target portion comprising one or more dies).

[0028] In operation, the illumination system IL receives a radiation beam B from a radiation source SO, for example via a beam transport system BD. The illumination system IL may include various types of optical components for directing, shaping and / or controlling the radiation, such as refractive, reflective, magnetic, electromagnetic, electrostatic and / or other types of optical elements, or any combination thereof. The illuminator IL may be used to condition the radiation beam B to have a desired spatial and angular intensity distribution in its cross-section at the plane of the patterning device MA.

[0029] The term "projection system" PS as used herein should be broadly interpreted as covering various types of projection systems, including refractive, reflective, catadioptric, anamorphic, magnetic, electromagnetic and / or electrostatic optical systems, or any combination thereof, as appropriate for the exposure radiation used, and / or other factors, such as the use of immersion liquid or the use of a vacuum. Any use of the term "projection lens" herein may be considered synonymous with the more general term "projection system" PS.

[0030] The lithographic apparatus may be of a type in which at least a portion of the substrate may be covered by an immersion liquid having a relatively high refractive index, such as water, so as to fill the space 11 between the projection system PS and the substrate W, which is also referred to as immersion lithography. More information on immersion techniques is given in US 6,952,253, which is incorporated by reference into the present disclosure.

[0031] The lithographic apparatus may also be of a type having two or more substrate supports WT (also known as a "dual stage"). In such a "multi-stage" machine, the substrate supports WT may be used in parallel, and / or a step of preparing a substrate W for subsequent exposure may be performed on a substrate W on one of the substrate supports WT, while another substrate W on another substrate support WT is being used to expose a pattern on another substrate W.

[0032] In addition to the substrate support WT, the lithographic apparatus may comprise a measurement platform. The measurement platform is arranged to hold sensors and / or cleaning means. The sensors may be arranged to measure properties of the projection system PS or properties of the radiation beam B. The measurement platform may hold a plurality of sensors. The cleaning means may be arranged to clean a part of the lithographic apparatus, e.g. a part of the projection system PS or a part of the system for providing immersion liquid. The measurement platform may be moved under the projection system PS when the substrate support WT is away from the projection system PS.

[0033] In operation, a radiation beam B is incident on a patterning device (e.g. a mask MA) held on a mask support MT and is patterned by a pattern (design layout) present on the patterning device MA. Having traversed the entire mask MA, the radiation beam B passes through a projection system PS which focuses the beam onto a target portion C of the substrate W. With the aid of a second positioning device PW and a position measurement system IF, the substrate support WT can be accurately moved, for example in order to position different target portions C in the path of the radiation beam B in a focused and aligned position. Similarly, the first positioning device PM and possibly another position sensor (which is not in the Figure 1 The patterning device MA may be accurately positioned relative to the path of the radiation beam B using the mask alignment marks M1, M2 and the substrate alignment marks P1, P2. Although the substrate alignment marks P1, P2 occupy dedicated target portions as illustrated, they may be located in spaces between target portions. When the substrate alignment marks P1, P2 are located between target portions C, they are referred to as scribe lane alignment marks.

[0034] In order to clearly illustrate the present invention, a Cartesian coordinate system is used. A Cartesian coordinate system has three axes, i.e., an x-axis, a y-axis, and a z-axis. Each of the three axes is orthogonal to the other two axes. A rotation around the x-axis is referred to as an Rx rotation. A rotation around the y-axis is referred to as an Ry rotation. A rotation around the z-axis is referred to as an Rz rotation. The x-axis and the y-axis define a horizontal plane, while the z-axis is in a vertical direction. The Cartesian coordinate system does not limit the present invention, but is only used for illustration. Alternatively, another coordinate system (such as a cylindrical coordinate system) can be used to illustrate the present invention. The orientation of the Cartesian coordinate system can be different, for example, so that the z-axis has a component along the horizontal plane.

[0035] Immersion technology has been introduced into lithography systems to enable improved resolution of smaller features. In an immersion lithography apparatus, a liquid layer of an immersion liquid having a relatively high refractive index is interposed in the space 11 between the apparatus's projection system (through which a patterned light beam is projected onto the substrate W) and the substrate W. The immersion liquid covers at least the portion of the substrate under the final element of the projection system PS. Thus, at least the portion of the substrate W that is undergoing exposure is immersed in the immersion liquid. The effect of the immersion liquid is to enable imaging of smaller features, because the wavelength of the exposure radiation is shorter in the liquid than in the gas. (The effect of the immersion liquid can also be seen as increasing the effective numerical aperture (NA) of the system and also increasing the depth of focus.)

[0036] In commercial immersion lithography, the immersion liquid is water. Typically, the water is high purity distilled water, such as ultrapure water (UPW) commonly used in semiconductor manufacturing plants. In an immersion system, the UPW is often purified and it may undergo additional processing steps before being supplied to the immersion space 11 as an immersion liquid. In addition to using water as the immersion liquid, other liquids with a high refractive index may also be used, for example: hydrocarbons (such as fluorinated hydrocarbons); and / or aqueous solutions. Furthermore, it has been envisioned that other fluids besides liquids may be used for immersion lithography.

[0037] In this specification, reference will be made to localised immersion in the description, wherein the immersion liquid is confined, in use, to a space 11 between a final element and a surface facing the final element. The facing surface is the surface of the substrate W, or a surface of a support platform (or substrate support WT) that is coplanar with the surface of the substrate W. (Note that references hereinafter to the surface of the substrate W also refer additionally or alternatively to the surface of the substrate support, unless otherwise expressly stated, and vice versa). A fluid handling structure 12 between the projection system PS and the substrate support WT serves to confine the immersion liquid to the immersion space 11. The space 11 filled with the immersion liquid is smaller in plane than the top surface of the substrate W, and the space 11 remains substantially stationary relative to the projection system PS whilst the substrate W and substrate support WT move underneath.

[0038] Other immersion systems have been envisaged, such as unconfined immersion systems (so-called "all-wet" immersion systems) and bath immersion systems. In unconfined immersion systems, the immersion liquid covers an area larger than the surface under the final component. The liquid outside the immersion space 11 is present as a thin liquid film. The liquid may cover the entire surface of the substrate W, or even the substrate W and a substrate support WT coplanar with the substrate W. In a bath system, the substrate W is completely immersed in a bath of immersion liquid.

[0039] The fluid handling structure 12 is a structure which supplies immersion liquid to the immersion space 11, removes immersion liquid from the space 11 and thereby confines immersion liquid to the immersion space 11. It comprises features that are part of a fluid supply system. An early fluid handling structure which comprises conduits which supply immersion liquid to the space 11 or withdraw immersion liquid from the space 11 and which relies on relative movement of a platform beneath the projection system PS for operation is the arrangement disclosed in PCT patent application publication number WO99 / 49504. In more recent designs, the fluid handling structure extends along at least a part of the boundary of the space 11 between the final element of the projection system PS and the substrate support WT or substrate W so as to partially define the space 11.

[0040] The fluid handling structure 12 may have a range of different functions. Each function may be derived from a corresponding feature that enables the fluid handling structure 12 to perform the function. The fluid handling structure 12 may be referred to by a number of different terms, each term referring to a function, such as a barrier member, a sealing unit, a fluid supply system, a fluid removal system, a liquid confinement structure, and the like.

[0041] As a barrier member, the fluid handling structure 12 is a barrier to the flow of immersion liquid from the space 11. As a liquid confinement structure, the structure confines the immersion liquid to the space 11. As a sealing unit, the sealing features of the fluid handling structure form a seal to confine the immersion liquid to the space 11. The sealing features may include an additional gas flow from an opening in the surface of a sealing member of the sealing unit, such as an air knife.

[0042] In an embodiment, the fluid handling structure 12 may supply immersion fluid and is therefore a fluid supply system.

[0043] In an embodiment, the fluid handling structure 12 may at least partially confine immersion fluid and thereby be a fluid confinement system.

[0044] In an embodiment, the fluid handling structure 12 may provide a barrier to the immersion fluid and thereby be a barrier member, such as a fluid confinement structure.

[0045] In an embodiment, the fluid handling structure 12 may create or use a gas flow, for example to help control the flow and / or position of the immersion fluid.

[0046] The gas flow may form a seal to confine the immersion fluid and therefore the fluid handling structure 12 may be referred to as a sealing unit; this sealing unit may be a fluid confinement structure.

[0047] In an embodiment, an immersion liquid is used as the immersion fluid. In this case, the fluid handling structure 12 may be a liquid delivery system. With reference to the preceding description, references in this paragraph to features defined relative to a fluid may be understood to include features defined relative to a liquid.

[0048] The lithographic apparatus has a projection system PS. During exposure of the substrate W, the projection system PS projects a patterned radiation beam onto the substrate W. In order to reach the substrate W, the path of the radiation beam B passes from the projection system PS through an immersion liquid, which is confined by a fluid handling structure 12 located between the projection system PS and the substrate W. The projection system PS has a lens element in contact with the immersion liquid, which is the last element in the path of the beam. This lens element in contact with the immersion liquid may be referred to as a "last lens element" or a "final element". The final element is at least partially surrounded by the fluid handling structure 12. The fluid handling structure 12 may confine the immersion liquid below the final element and above the facing surface.

[0049] Figure 2A and 2B Different features that may be present in variations of the fluid handling structure 12 are shown. Unless described differently, the designs may share similarities with Figure 2A and 2B Some of the same features. The features described herein may be selected individually or in combination as shown or as required.

[0050] Figure 2AA fluid handling structure 12 is shown surrounding the bottom surface of the final element 100. The final element 100 has an inverted frustoconical shape. The frustoconical shape has a flat bottom surface and a conical surface. The frustoconical shape protrudes from the flat surface and has a bottom flat surface. The bottom flat surface is an optically active portion of the bottom surface of the final element 100 through which the radiation beam B can pass. The final element 100 may have a coating 30. The fluid handling structure 12 surrounds at least part of the frustoconical shape. The fluid handling structure 12 has an inner surface, which faces the conical surface of the frustoconical shape. The inner surface and the conical surface have complementary shapes. The top surface of the fluid handling structure 12 is substantially flat. The fluid handling structure 12 can be assembled around the frustoconical shape of the final element 100. The bottom surface of the fluid handling structure 12 is substantially flat, and in use, the bottom surface may be parallel to the facing surface of the substrate support WT and / or the substrate W. The distance between the bottom surface and the facing surface may be in the range of 30 to 500 microns, ideally in the range of 80 to 200 microns.

[0051] The fluid handling structure 12 extends closer to said facing surfaces of the substrate W and substrate support WT than the final element 100. Thus, a space 11 is defined between the inner surface of the fluid handling structure 12, the flat surface of the frustoconical portion and said facing surface. During use, the space 11 is filled with immersion liquid. The immersion liquid fills at least part of the buffer space between the complementary surfaces between the final element 100 and the fluid handling structure 12, and in one embodiment fills at least part of the space between the complementary inner surface and the conical surface.

[0052] Immersion liquid is supplied to the space 11 through openings formed in the surface of the fluid handling structure 12. The immersion liquid may be supplied through supply openings 20 in the inner surface of the fluid handling structure 12. Alternatively or additionally, the immersion liquid is supplied from a lower supply opening 23 formed in the lower surface of the fluid handling structure 12. The lower supply opening 23 may surround the path of the radiation beam B and it may be formed by a series of openings in an array. Immersion liquid is supplied to fill the space 11 so that the flow through the space 11 under the projection system PS is laminar. Additionally, supplying the immersion liquid from the lower supply opening 23 below the fluid handling structure 12 also prevents bubbles from entering the space 11. This supply of immersion liquid acts as a liquid seal.

[0053] The immersion liquid may be recovered from a recovery opening 21 formed in the interior surface. The recovery of the immersion liquid through the recovery opening 21 may be achieved by applying a negative pressure; the recovery through the recovery opening 21 is a result of the speed at which the immersion liquid flows through the space 11; or the recovery may be a result of both. When viewed in plan, the recovery opening 21 may be located on the opposite side of the supply opening 20. Additionally or alternatively, the immersion liquid may be recovered through an overflow opening 24 located on the top surface of the fluid handling structure 12. In an embodiment, the supply and recovery openings 20, 21 may swap their functions (i.e., the flow direction of the liquid is opposite). This allows the flow direction to be changed according to the relative movement of the fluid handling structure 12 and the substrate W.

[0054] Additionally or alternatively, the immersion liquid may be recovered from below the fluid handling structure 12 via a recovery opening 25 formed in the bottom surface of the fluid handling structure 12. The recovery opening 25 may be used to hold (or "pin") a meniscus 33 of the immersion liquid to the fluid handling structure 12. The meniscus 33 is formed between the fluid handling structure 12 and the facing surface, and the meniscus 33 acts as a boundary between the liquid space and the gaseous external environment. The recovery opening 25 may be a porous plate that may recover the immersion liquid in a single-phase flow. The recovery openings in the bottom surface may be a series of pinning openings 32 through which the immersion liquid is recovered. The pinning openings 32 may recover the immersion liquid of a two-phase fluid.

[0055] Optionally, the air knife opening 26 is radially outward relative to the interior surface of the fluid handling structure 12. Gas can be supplied at an increased rate through the air knife opening 26 to assist in confining the immersion liquid in the space 11. The supplied gas can be humidified and it can substantially contain carbon dioxide. The gas recovery opening 28 for recovering the gas supplied through the air knife opening 26 is radially outward from the air knife opening 26. Additional openings may be present in the bottom surface of the fluid handling structure 12, for example, open to the atmosphere or a gas source. For example, additional openings may be present between the air knife opening 26 and the gas recovery opening 28, and / or between the pinning opening 32 and the air knife opening 26.

[0056] Figure 2B Shown with Figure 2A Common features share the same reference numerals.The fluid handling structure 12 has an inner surface which is complementary to the conical surface of the frustoconical shape.The lower surface of the fluid handling structure 12 is closer to the facing surface than the bottom flat surface of the frustoconical shape.

[0057] Immersion liquid is supplied to the space 11 through supply openings 34 formed in the inner surface of the fluid handling structure 12. The supply openings 34 are located towards the bottom of the inner surface, possibly below the bottom surface of the frustoconical shape. The supply openings 34 are located around the inner surface, spaced around the path of the radiation beam B.

[0058] The immersion liquid is recovered from the space 11 through the recovery opening 25 in the lower surface of the fluid handling structure 12. When the facing surface moves below the fluid handling structure 12, the meniscus 33 can migrate on the surface of the recovery opening 25 in the same direction as the movement of the facing surface. The recovery opening 25 can be formed by a porous member. The immersion liquid can be recovered in a single phase. In one embodiment, the immersion liquid is recovered as a two-phase flow. The two-phase flow is received in a chamber 35 within the fluid handling structure 12, in which the two-phase flow is separated into liquid and gas. The liquid and gas are recovered from the chamber 35 through separate channels 36, 38.

[0059] The inner periphery 39 of the lower surface of the fluid handling structure 12 extends away from the inner surface into the space 11 to form a plate 40. The inner periphery 39 forms a small hole, which can be sized to match the shape and size of the radiation beam B. The plate 40 can be used to isolate immersion liquid on either side thereof. The supplied immersion liquid flows inwardly towards the hole, through the inner hole, and then flows radially outwardly under the plate 40 to around the recovery opening 25.

[0060] In one embodiment, the fluid handling structure 12 may be in two parts, such as Figure 2B : an inner part 12a and an outer part 12b. The inner part 12a and the outer part 12b can be moved relative to each other in a plane parallel to the facing surfaces. The inner part 12a can have a supply opening 34 and it can have an overflow recovery member 24. The outer part 12b can have a plate 40 and a recovery opening 25. The inner part 12a can have an intermediate recovery member 42, which is used to recover immersion liquid flowing between the inner part 12a and the outer part 12b.

[0061] exist Figure 2A and 2B In the example of Figure 2A Recycling opening 21, Figure 2A and 2B Overflow recovery part 24, Figure 2A and 2B The recovery opening 25 in both Figure 2A The pinning opening 32 in the Figure 2B channels 36, 38) and / or supply openings (e.g. Figure 2A The supply opening 20, Figure 2AThe lower supply opening 23 in the Figure 2B At least one of the supply openings 34 in the fluid delivery system 12 can be used to control the amount of immersion liquid in the space 11. The position of the meniscus 33 and the position of the meniscus 22 will vary depending on the amount of immersion liquid in the space 11, the meniscus 22 being similar to the meniscus 33 except that it is formed between another part of the fluid delivery system 12 and the final element 100.

[0062] The substrate support WT may comprise a substrate holder 200 configured to support the substrate W. Figure 3A The substrate holder 200 and an associated substrate W supported by the substrate holder 200 are illustrated in cross section. The substrate holder 200 comprises a body 201 having a body surface 202. The body surface 202 faces a lower surface of a substrate W, ie the lower surface of the substrate W facing the substrate holder 200, in use.

[0063] In the central region of the main body surface 202, a plurality of support elements 210 protrude from the main body surface 202. Each support element 210 has a distal end surface 211 (eg, Figure 3B ), the distal end surface 211 is configured to support the substrate W. For example, during illumination of the substrate W, the support element 210 may be configured to contact the lower surface of the substrate W. The support elements 210 are arranged in a pattern relative to each other in a plan view. The pattern is to support the substrate W and reduce any bending of the substrate W toward the body surface 202 to an acceptable amount.

[0064] The plan area of ​​each support element 210 is relatively small compared to the plan area of ​​the substrate W. Therefore, the support element 210 only contacts a small area of ​​the lower surface of the substrate W. This reduces the chance of contaminants being transferred from the substrate holder 200 to the substrate W.

[0065] A pressure differential is established across the substrate W. For example, the space between the body 201 of the substrate holder 200 and the substrate W is connected to a negative pressure that is lower than the higher pressure above the substrate W. When in use, for example when the substrate W is irradiated, the pressure differential generates a force that holds the substrate W to the substrate holder 200. In other words, the substrate holder 200 has a member for clamping the substrate W to the substrate holder 200.

[0066] In an immersion lithography apparatus, liquid will be present near the edge of the substrate W at least at some time during exposure of the substrate W. Due to the negative pressure between the body 201 of the substrate holder 200 and the lower surface of the substrate W, this liquid will be sucked around the edge of the substrate W and below the substrate W. In order to reduce the contact of the liquid with the lower surface of the substrate W, and in particular the contact occurring at the area where the support element 210 contacts the substrate W, a sealing unit may be provided, the sealing unit comprising at least one member protruding from the body surface 202 of the body 201. In general, the liquid between the substrate W and the body surface 202 passes through the sealing unit radially inwardly. The sealing unit may include a first sealing member and a second sealing member. The first sealing member may be radially outward of the second sealing member and surround the second sealing member. The first sealing member may be used to reduce the pressure in the area between the first sealing member and the second sealing member. The second sealing member may be configured to limit or prevent the liquid from flowing or passing radially inwardly through the second sealing member. The first sealing member may also at least partially limit the liquid from passing radially inwardly through the first sealing member. The sealing unit may be configured to restrict the passage of liquid around substantially the entire circumference of the sealing unit (i.e. around the entire substrate W). In other words, due to the presence of the sealing unit, the amount of liquid at a position radially outward of the sealing unit is restricted or prevented from moving radially inward to a position radially inward of the sealing unit. This means that the presence of the sealing unit reduces the amount of liquid at a position radially inward of the sealing device compared to the case where no sealing device is provided. Liquid can be prevented from simply bypassing the sealing unit.

[0067] The sealing unit may be part of a sealing mechanism, such as a seal formed close to or around a radially outer edge of the substrate W. The sealing unit may include further components for limiting the passage of liquid radially inwards.

[0068] One purpose of the sealing unit is to restrict the flow of gas (which may be undesirably wet) radially inwards towards the support element 210. This enables the generation of a negative pressure around the support element 210, which is necessary to clamp the substrate W to the substrate holder 200. It is advantageous to allow some gas to flow over the sealing unit so that the substrate W can be quickly removed from the substrate holder 200 when the negative pressure source generating the negative pressure around the support element 210 is turned off. If the gas flow through the sealing unit is too low, the pressure around the support element 210 balances or equalizes with the pressure above the substrate W, thereby releasing the substrate W and taking too much time. The substrate holder 200 may be configured to generate an overpressure below the lower surface of the substrate W to enable faster removal of the substrate W.

[0069] The sealing unit may include at least one sealing element. The sealing element may include a first sealing member 220 and a second sealing member 240. The first sealing member 220 may include a Figure 3Aand 3B The second sealing member 240 will be described in further detail below. The first sealing member 220 may be configured to restrict the flow of gas / fluid radially inwardly toward the first sealing member 220. For example, in a dry lithography system, the sealing unit may include only the first sealing member 220.

[0070] The first sealing member 220 has an upper surface 221, which is the distal end of the first sealing member 220. Thus, the upper surface 221 is positioned away from the contact point between the first sealing member 220 and the main body surface 202 (even if the first sealing member 220 and the main body 201 are integrated with each other). In use, the upper surface 221 is configured to form a gap between the upper surface 221 and the lower surface of the substrate W, that is, the upper surface 221 is configured to be slightly closer to the main body surface 202 than the distal end surface 211 of the support element 210. This is advantageous because this arrangement allows gas to be sucked in above the first sealing member 220 (below the substrate W) just before the substrate W is removed, while allowing the passage of liquid in the same direction to be restricted. This is achieved without contacting the large area of ​​the lower surface of the substrate W, which will cause contaminants to be transferred to the substrate W from the first sealing member 220 in a harmful manner. This will also make it more problematic to remove the substrate W from the substrate holder 200.

[0071] like Figure 3A and Figure 3B As shown, the radially outward most of the plurality of support elements 210 is at some distance from the edge of the substrate W. In the absence of any other features supporting the substrate W radially outwardly at the radially outward most support element 210, downward bending of the edge of the substrate W may occur, in particular during an unloading process of the substrate W. This is due to the negative pressure below the substrate W compared to above the substrate W.

[0072] In use, an underpressure may be provided in a central region of the substrate holder 200 between the body surface 202 and the substrate W. This underpressure is the reason why the substrate W may be clamped to the substrate holder 200 during use. This clamping underpressure may be of a lower magnitude (i.e. a less severe vacuum) than the underpressure at radially outward regions of the support element 210.

[0073] During unloading of the substrate W, the pressure between the body surface 202 and the substrate W may be controlled to allow unloading of the substrate W. The unloading of the substrate W may include a step of increasing the pressure between the body surface 202 and the substrate W. This is accomplished by Figure 3A. For example, when the substrate W is to be unloaded, the vacuum under the substrate W can be removed by injecting high-pressure air under the substrate W. Thus, the unloading of the substrate W includes at least one release step, for example, increasing the pressure between the body 201 and the lower surface of the substrate W. The advantage of generating an overpressure under the substrate W during unloading is that any fluid between the substrate W and the body surface 202 will be pushed radially outward. However, this usually results in an overpressure under the center of the substrate W and a negative pressure around the edge of the substrate W. Thus, the substrate W may deform and bulge upward in the middle of the substrate W, and extend downward as a cantilever at the edge of the substrate W.

[0074] Figure 3A and 3B 2 represents the prior art and shows that when the substrate W bulges upward in the middle thereof, the side edges of the substrate W will scrape over the radially outermost support element 210 and the first sealing member 220. Figure 3B As shown in the enlargement in FIG. 2 , there is interaction between the distal end surface 211 of the radially outermost support element 210 and the substrate W, and between the upper surface 221 of the first sealing member 220 and the substrate W. As indicated above, this may have a detrimental effect on the system.

[0075] The scraping of the substrate W over the distal end face 211 of the support element 210 exerts a force on the support element 210. Any interaction between the substrate W and one of the support elements 210 may result in wear on the support element 210. This is a problem because it may change the exact height of the support element 210. If the height of the support element 210 is changed, this may lead to focusing and / or coverage problems when irradiating further substrates W and / or further layers of the same substrate W. If the support element 210 becomes too damaged, it may be necessary to replace the substrate holder 200. Therefore, preventing damage to the support element 210 provides a more stable long-term performance of the substrate holder 200.

[0076] When the lower surface of substrate W scrapes over the edge of first sealing member 220, interaction between substrate W and first sealing member 220 occurs, i.e., in known systems, the lower surface of substrate W contacts first sealing member 220 via single point contact (in cross section) during unloading. This results in high stress points on the lower surface of substrate W, and causes scratches on the lower surface of substrate W. Scratches can produce particles of substrate W or even first sealing member 220, which can contaminate the system. These particles are usually close to the edge of substrate W, and therefore may end up on the top of substrate W. In addition, interaction may cause wear of first sealing member 220 in an undesirable manner, i.e., cause wear of first sealing member 220 in a manner that affects the first sealing member 220 (and thus affects the entire sealing unit) to achieve the desired function. Thus, it is desirable to reduce the interaction between first sealing member 220 and substrate W in a manner that may affect the ability of first sealing member 220 to control the pressure between first sealing member 220 and second sealing member 240 and / or control liquid through the inward movement of first sealing member 220. Therefore, preventing damage to the first sealing member 220 in certain areas for providing a seal provides more stable long-term performance of the substrate holder 200 .

[0077] Wear is detrimental because it leads to contamination of the substrate W and changes in the clamping properties of the substrate holder 200, and thus to deformation of the substrate W. The presence of liquid between the support element 210 and the underside of the substrate W can also lead to wear (if the substrate holder 200 is ceramic), and can cause friction changes. Deformations of the substrate W can lead to imaging errors (e.g. overlay errors and / or focus errors), as can contamination. The presence of liquid on the underside of the substrate W is generally detrimental because it can lead to thermal stability problems of the substrate W, or difficulties when droplets are lost during the unloading process of the substrate W.

[0078] A similar problem may occur during loading of a substrate W onto the substrate holder 200. Thus, during loading, the substrate W may be deformed in a certain manner, causing the substrate W to scratch the substrate holder 200 as described above. Additionally or alternatively, during loading of the substrate W in a dry lithography apparatus, the substrate W may tilt during loading, which may cause the edge of the substrate W to contact the edge of the support element 210, causing wear.

[0079] As will be described below, the substrate holder 200 of the present invention eliminates some of these difficulties due to the position and shape of the first sealing member 220, which is configured to interact with the substrate W during unloading (or loading) of the substrate W while still providing a mechanism as part of the sealing unit (e.g., by restricting the passage of fluid / gas radially inward through the first sealing member 220). In addition, the unloading step may be referred to as a releasing step, and thus, the term "releasing" may be interchanged in the portion of the description regarding unloading of the substrate W below.

[0080] In the present invention, there is provided Figure 3A and 3B The substrate holder 200 described above. However, the first sealing member 220 is configured to solve some of the above problems. Figure 3A and 3B The differences between at least the first sealing member 220 are described.

[0081] In more detail, the present invention provides a substrate holder 200 for a lithographic apparatus, and it is configured to support a substrate W. The substrate holder 200 includes a body 201 having a body surface 202. The substrate holder 200 also includes a plurality of support elements 210 protruding from the body surface 202, wherein each support element 210 has a distal end surface 211 configured to support the substrate W. The support element 210 may have a first height. The substrate holder 200 also includes a sealing unit. The sealing unit may be configured to limit the liquid between the substrate W and the body surface 202 from passing radially inward through the sealing unit. The sealing unit may include a first sealing member 220 protruding from the body surface 202 and having an upper surface 221. The first sealing member 220 may have a second height, which is less than the first height. Thus, the support element 210 may be higher than the first sealing member 220. Similarly, the support element 210 may be higher than the second sealing member 240 (if the second sealing member is provided). The sealing unit may include a second sealing member 240 protruding from the body surface 202. The second sealing member 240 may be positioned radially inward of the first sealing member 220. The first sealing member 220 may be positioned radially outward of and surrounding the plurality of support elements 210. The second sealing member 240 is optional and may be particularly beneficial for an immersion system in order to prevent liquid from passing radially inward.

[0082] The first sealing member 220 and the second sealing member 240 can be configured together to limit or prevent liquid and gas from passing radially inward through the sealing unit. The first sealing member 220 can be configured to form a low pressure area between the first sealing member 220 and the second sealing member 240. Thus, the pressure of the space (i.e., the sealing area) between the first sealing member 220 and the second sealing member 240 can be lower than the pressure around the sealing unit. The low pressure area between the first sealing member 220 and the second sealing member 240 reduces the amount of liquid that moves radially inward in the space between the first sealing member 220 and the second sealing member 240.

[0083] The first sealing member 220 may be configured to provide a radially inward pressure drop of the first sealing member 220 relative to the pressure in the radially outward region of the sealing unit. For example, the first sealing member 220 may be mainly used to form a pressure drop from the surrounding environment to about -500mbar, and thus form a vacuum for clamping the substrate W. The second sealing member 240 may be used to maintain a pressure difference of about 25mbar between the interior of the substrate holder 200 and the sealing area, such as -475mbar. This small pressure difference may cause a water body (capillary) to be generated in a small gap between the second sealing member 240 and the substrate W. The main function of the second sealing member 240 may be to limit water to move further inward. The second sealing member 240 may be configured to reduce or prevent liquid from passing radially to the interior of the sealing unit.

[0084] The cross-sectional area of ​​the first sealing member 220 in plan view may be much larger than the cross-sectional area of ​​the support element 210. In plan view, the relatively large area of ​​the first sealing member 220 results in a greater resistance to liquid passing radially inwardly through the first sealing member 220 between the substrate W and the body surface 202. The cross-sectional shape of the first sealing member 220 in plan view may be circular, or more specifically, annular or ring-shaped. Thus, the first sealing member 220 may have an annular shape.

[0085] The cross-sectional area of ​​the second sealing member 240 in plan view may be much larger than the cross-sectional area of ​​the support element 210. In plan view, the relatively large area of ​​the second sealing member 240 results in a greater resistance to the liquid passing radially inwardly through the second sealing member 240 between the substrate W and the body surface 202. The first sealing member 220 and the second sealing member 240 may have similar or identical cross-sectional areas. The cross-sectional shape of the second sealing member 240 in plan view may be circular, or more specifically, ring-shaped or annular. Therefore, the second sealing member 240 may have an annular shape.

[0086] The first sealing member 220 can surround or surround the plurality of support elements 210. Thus, the first sealing member 220 can generally surround the entire circumference of the plurality of support elements 210. In other words, for example, when viewed in a plan view, the first sealing member 220 can surround or circle the plurality of support elements 210. The first sealing member 220 can be a continuous (although not necessarily uniform in cross section) barrier member around the support element 210. Alternatively, the first sealing member 220 can be formed by a plurality of sections. The plurality of sections can substantially form an entire annular ring. In other words, the first sealing member 220 can be formed by a plurality of separated or separate sections that substantially form an annular ring. In a segmented annular ring, there may be a plurality of sealing member parts, with a gap between each adjacent sealing member part. The gap between adjacent sealing member parts can be the same length as or shorter than the length of any one or two of the adjacent parts. The distance between each sealing member part can be equal to the width of one or both of the adjacent sealing member parts, or smaller than the width of one or both of the adjacent sealing member parts. At least one of the gaps between adjacent sealing member parts (that is, the interval between adjacent parts) can be about tens or hundreds of microns. At least one of the gaps between adjacent sealing member parts can be roughly 10 microns narrow. At least one of the gaps can be between 0.5 and 5mm. Some or all of the intervals can have these sizes. It may be advantageous to set a small gap, because any contaminant such as from the interaction between the lower side of the substrate W and the first sealing member 220 can be captured in the gap, while still providing a relatively large contact area on the first sealing member 220.

[0087] The second sealing member 240 may be located radially inward of the first sealing member 220. The second sealing member 240 may be radially outward of some or all of the plurality of support elements 210. Some of the plurality of support elements 210 may be disposed radially outward of the second sealing member 240. Thus, some of the plurality of support elements 210 may be disposed between the first sealing member 220 and the second sealing member 240. This will be described below with reference to Fig.10 Described in further detail.

[0088] The second sealing member 240 may surround at least part (if not most) of the plurality of support elements 210. Thus, the second sealing member 240 may substantially surround the entire circumference of at least some (if not most) of the plurality of support elements 210. In other words, for example, when viewed in a plan view, the second sealing member 240 may enclose at least some (if not most) of the plurality of support elements 210. The second sealing member 240 may be a continuous (although not necessarily uniform in cross section) barrier member surrounding the support element 210. Alternatively, the second sealing member 240 may be formed by a plurality of sections. The plurality of sections may substantially form an entire annular ring. In other words, the second sealing member 240 may be formed by a plurality of separate or separated sections that substantially form an annular ring. In a segmented annular ring, there may be a plurality of sealing member parts, with a gap between each adjacent sealing member part. The gap between adjacent sealing member parts may be the same length as or shorter than the length of any one or two of the adjacent parts. The distance between each sealing member part can be equal to the width of one or both of the adjacent sealing member parts, or smaller than the width of one or both of the adjacent sealing member parts. At least one of the gaps between adjacent sealing member parts (that is, the gap between adjacent parts) can be about tens or hundreds of microns. At least one of the gaps between adjacent sealing member parts can be approximately 10 microns narrow. At least one of the gaps can be between 0.5 and 5mm. Some or all of the intervals can have these sizes. It may be advantageous to set a small gap, because any contaminant such as from the interaction between the lower side of the substrate W and the first sealing member 220 can be captured in the gap.

[0089] The upper surface 221 of the first sealing member 220 has a contact area 222, which is configured to contact the substrate W during the unloading of the substrate W. The upper surface 221 of the first sealing member 220 is configured so that it will not contact the substrate W when the substrate W is irradiated, that is, the first sealing member 220 is not used to support the substrate W during irradiation. The contact area 222 is configured so that it will not contact the substrate W when the substrate W is irradiated, that is, the contact area 222 is not used to support the substrate W during irradiation. The contact area 222 can be configured to contact only the substrate W during the unloading of the substrate W. In the previously known system, it is not expected that the upper surface of any sealing member provided will contact the substrate W during the unloading (or loading) of the substrate W. In addition, in the previously known system, during loading or unloading, there may not be any contact between the sealing member and the substrate, so all wear may have occurred on the support element 210.

[0090] In the present invention, the contact area 222 may be arranged at a sufficiently sufficient distance from the plurality of support elements 210 so that during unloading of the substrate W, the force applied by the substrate W to the first sealing member 220 is greater than the force applied by the substrate W to the plurality of support elements 210. This means that during unloading of the substrate W, the wear of the support element 210 is less than the wear of the first sealing member 220. This means that, in contrast to the case of using Figure 3A and 3B The configuration shown can reduce the wear of the support element 210 compared to the wear of the first sealing member 220 when releasing the substrate. Ideally, the first sealing member 220 can be the main feature that contacts the substrate W during unloading (i.e., ideally, at some point during unloading), and the substrate W only contacts the contact surface 222 and does not contact the support element 210.

[0091] In other words, the point and / or area of ​​the first sealing member 220 configured to contact the substrate W during unloading of the substrate W is sufficiently far away from the support element 210 so that the wear on the radially outermost support element 210 is less than the wear on the first sealing member 220. For example, Figure 4 As shown, if the first sealing member 220 is formed with a uniform cross-section around the circumference, the cross-section shows a single point of contact, but this will be provided around the circumference of the first sealing member 220 and the contact area 222 will be provided by the area around the entire first sealing member 220.

[0092] The contact region 222 may simply be an area of ​​the first sealing member 220 that is configured to make contact with the substrate W at some point during the unloading process. This will typically be a known, defined area. Figure 4 , the contact area 222 is shown as the radially outermost point on the upper surface 221 of the first sealing member 220. The contact area 222 may be a point located between the upper surface 221 of the first sealing member 220 and the radially outer edge 223 of the first sealing member 220. In other words, the contact area 222 may provide an area between the upper surface 221 and the radially outer edge 223. Thus, the contact area 222 may form a connection between the upper surface 222 and the radially outer edge 223. This may be a point where the upper surface 221 and the radially outer edge 223 would otherwise meet, such as Figure 4 Alternatively, the contact area 222 may be an area between the two surfaces, for example, Fig. 6A As shown. There may be a gradient change between the upper surface 221 and the contact area 222. There may be a gradient change between the surface of the radial outer edge 223 and the contact area 222.

[0093] The contact area 222 may not be uniform around the first sealing member 220 and may be configured to provide increased contact area in certain locations where particulate contaminants are known to be larger.

[0094] As is known, the first sealing member 220 should be arranged within a certain distance of the radially outermost support element 210 in order to maintain a desired pressure between the substrate W and the body 201. Thus, the present invention teaches a departure from or opposite to this by providing a certain distance between the contact area 222 and the radially outer edge of the radially outermost support element 210 and at the same time maintaining the desired pressure.

[0095] The position of the contact area 222 relative to the support element 210 can be controlled in a variety of different ways. Figure 4 As shown, the main dimensions relate to the distance between the radially outer edge 212 of the distal end face 211 of the radially outermost support element 210 and the outer upper edge of the upper surface 221 of the first sealing member 220. The dimensions relate to these specific parts of the support element 210 and the first sealing member 220, because these specific parts are the parts of these parts that will be in contact with the lower surface of the substrate W during unloading of the substrate W.

[0096] The distance may be defined by a radial distance D. The distance may additionally or alternatively be defined by a distance y between the distal end surface 211 of the support element 210 and the upper surface 221 of the first sealing member 220. Both distances will affect how the substrate W interacts with each of these components during the unloading process.

[0097] In this example, the contact area 222 is shown as an edge contact point in cross section. Thus, in this embodiment, the contact area 222 is formed by the same contact point around the circumference of the first sealing member 220. This contact area 222 is formed by the same contact point around the circumference of the first sealing member 220. Figure 4 The Vice Premier will be with Figure 3A and 3B However, the position of the contact area 222 relative to the support element 210 will differ from the relative position of the contact area of ​​the prior art and will be configured to reduce wear of the support element 210 during unloading of the substrate W.

[0098] In one embodiment, the radial distance D from the radially outer edge 212 of the distal end surface 211 to the contact area 222 is greater than 1000 microns, and preferably greater than 1500 microns. This means that the contact area 222 can be far enough away from the support element 210 to reduce the contact between the support element 210 and the substrate W during loading and / or unloading. Additionally or alternatively, the height difference between the radially outermost support element 210 and the first sealing member 220 is greater than 1000 microns, and preferably greater than 1500 microns. Figure 4 y, between about 2 microns and 8 microns. The height difference between the radially outermost support element 210 and the first sealing member 220 is the distance between the upper surface 221 of the first sealing member 220 and the distal end surface 211 in the y direction, wherein the y direction is orthogonal to the plane including the radial direction. During loading and / or unloading, having a height difference can also reduce the contact between the support element 210 and the substrate W.

[0099] Providing the contact area 222 at such a distance means that during loading and / or unloading of the substrate, the substrate W will have a greater interaction with the first sealing member 220 rather than the radially outermost support element 210. In practice, this means that the first sealing member 220 acts as a sacrificial wear area. This may result in a significant reduction in the wear of the outermost support element 210. The distance between the radially outer edge 212 and the contact area 222 may be optimized in the radial direction and / or in the y-direction to minimize the friction between the outermost support element 210 and the substrate W during loading and / or unloading of the substrate W. The optimal values ​​of the distance D and the distance y may vary depending on the substrate holder 200 and / or the substrate W and / or the application to which the substrate W is applied.

[0100] The length x of the first sealing member 220 in the radial direction may be greater than 300 microns, or preferably greater than 500 microns. This may be beneficial because the contact area 222 of the first sealing member 220 may be gradually worn away by the interaction between the substrate W and the first sealing member 220 during unloading. If the first sealing member 220 is long enough in the radial (i.e. x) direction, the wear of the first sealing member 220 will be less likely to affect the ability of the first sealing member 220 to perform the function of limiting the passage of liquid radially inward from the first sealing member 220. Thus, providing a first sealing member 220 with a sufficient length (e.g. greater than 300 microns, or preferably greater than 500 microns) may mean that the first sealing member 220 is configured to better control the liquid at the edge of the substrate holder 200 over a longer period of time than known sealing elements, because the first sealing member 220 of the present invention will not be worn away by the interaction with the substrate W in the same way.

[0101] Optionally, the substrate holder 200 may include a coating. The coating may be used to cover at least a portion of the substrate holder 200. For example, as described below, the coating may form a portion of the first sealing member 220 and / or a portion of at least one of the plurality of support elements 210. The coating may be made of diamond-like carbon (DLC, such as a-CH), diamond, silicon carbide (such as SiSiC or SiC), boron nitride (BN) or boron nitride carbon (BCN). The coating may be made substantially or entirely of these materials and / or any derivatives of these materials. These materials may be particularly beneficial due to a combination of hardness and Young's modulus. Thus, these materials may have a desired degree of toughness (hardness / Young's modulus).

[0102] The coating can be a thin layer such as having a thickness as described below. This coating can be used to cover the surface of the various parts of the substrate holder 200. The coating can be substantially uniform over any part of the substrate holder 200 including the coating. For example, the coating can be set to a substantially uniform layer of thickness on the first sealing member 220 and / or at least one of the plurality of support elements 210. For example, the thickness of the coating can vary less than 50% of the coating thickness of the thickest part of the coating in any part. Preferably, the thickness variation is less than or equal to 30%, or more preferably less than or equal to 20%.

[0103] For example, the coating may be beneficial to reduce wear of the substrate holder 200 and / or scratching of the substrate W on any portion of the substrate holder 200 that contacts the substrate during a loading or unloading process of the substrate W. The coating may be beneficial to improve the wear resistance of the coated features. This may prevent the features having the coating from wearing.

[0104] The coating may be thin. More specifically, the coating may have a thickness between about 0.2 μm and 2 μm. Preferably, the coating has a thickness between about 0.2 μm and 1.5 μm. Preferably, the coating has a thickness between about 0.2 μm and 1 μm. More generally, preferably, the thickness is less than or equal to 2 μm, or preferably less than or equal to 1.5 μm, or preferably less than or equal to 1 μm. The thickness referred to here may be an average thickness over a particular portion of the substrate holder 200.

[0105] like Figure 5 As shown, at least one of the plurality of support elements 210 may include a coating 214. The coating 214 may have the above-described properties. Figure 5As shown, the coating 214 may form the distal end surface 211 of at least one of the plurality of support elements 210. In other words, the coating 214 may be disposed on the distal end of the protrusion forming at least one of the plurality of support elements 210. The coating 214 may provide a protective layer on the distal end of at least one of the plurality of support elements 210. Figure 5 As shown, the coating 214 may be disposed on a single one or more of the plurality of support elements 210 , and optionally, disposed on all of the plurality of support elements 210 .

[0106] The coating 214 of at least one support element of the plurality of support elements 210 may be otherwise referred to as a support member coating. As already described, the coating 214 may reduce the wear of the at least one support member 210. Reducing the wear of the at least one support member 210 is beneficial because it may increase the useful life of the substrate holder 200 so that it may be used to process more substrates.

[0107] In addition, if Figure 5 As shown, the first sealing member 220 may include a coating 224. The coating 224 may have the above-mentioned properties. Figure 5 As shown, the coating 224 may form an upper surface 221 of the first sealing member 220. In other words, the coating 224 may be provided on the distal end of the protrusion forming the first sealing member 220. The coating 224 may provide a protective layer on the end of the first sealing member 220. When the coating 224 is provided on the first sealing member 220, the contact area 222 of the first sealing member 220 may be on the coating 224. The coating 224 on the first sealing member 220 may be additionally referred to as a sealing member coating.

[0108] The coating 224 can reduce the wear of the first sealing member 220. Reducing the wear of the first sealing member 220 is beneficial because it means that the first sealing member 220 can continue to act as a seal more effectively for a larger number of substrates W being processed than if the coating was not provided. In addition, if the first sealing member 220 is worn, the substrate W may contact the at least one support member 210 during loading and unloading, which may reduce the useful life of the substrate holder 200. Thus, it is beneficial to prevent the wear of the first sealing member 220 to protect the at least one support member 210 for as long as possible / for the processing of as many substrates as possible.

[0109] like Figure 5As shown, the coating 214 may be provided on at least one of the plurality of support elements 210, and the coating 224 may be provided on the first sealing member 220. However, it is not necessary to provide coatings for multiple parts of the substrate holder 200. Thus, for example, a coating may be provided on only one or the other (i.e., the first sealing member 220, or at least one of the plurality of support elements 210).

[0110] Although the above features can reduce wear on the outermost support element 210, this can be improved by changing the shape of the contact area 222. In addition or alternatively to the above features, the contact area 222 of the first sealing member 220 can have a specific geometry. For example, in a cross section through the first sealing member 220 in the radial direction, the profile of the contact area 222 can have a shape configured so that during unloading of the substrate W, the substrate W contacts the sealing first member 220 via at least two different points of the profile. Fig. 6A An example of a contact area 222 configured so that the substrate W contacts the first sealing member 220 via at least two different points during unloading is shown in FIG.

[0111] The contour of the contact region 222 is shaped in such a way that the substrate W contacts the region in the cross section through the first sealing member 220 rather than a single point (eg, Figure 3A , 3B 4). Additionally or alternatively, the substrate W may interact with the contact area 222 via various different points, for example, the contact point may change during unloading of the substrate W, as will be described in some examples below.

[0112] It is beneficial to contact the substrate W with the first sealing member 220 via at least two different points on the profile, because the local stress on the first sealing member 220 can be reduced. This is because during loading and / or unloading, there is an increased contact area between the substrate W and the first sealing member 220, and / or the force from the substrate W is applied to the different points of the first sealing member 220. Although different geometric shapes can be set, different geometric shapes provide the contact between the substrate W and the first sealing member 220 at multiple points, which spreads the force and reduces the local stress. Thus, this reduces the force acting on the lower side of the substrate W. Then, this reduces the formation of scratches on the lower surface of the substrate W (scratches may produce particles that contaminate the system). Thus, setting such a contact area 222 can be beneficial to reduce pollution.

[0113] Various different geometries of the profile may be provided. For example, the profile may be linear from the upper surface 221 of the first sealing member 220 to the radially outer edge 223 of the first sealing member 220. Fig. 6A, where the contact area 222 is formed by an inclined portion having an angle θ. In other words, the first sealing member 220 may have a beveled edge or a chamfered edge that forms the contact area 222. The linear profile from the upper surface 221 of the first sealing member 220 to the radially outer edge 223 of the first sealing member 220 may be at a negative gradient of between about 0.15 microns / mm and 3 microns / mm relative to the upper surface 221 of the first sealing member 220.

[0114] as Figure 4 The distance between the first sealing member 220, the contact area 222 and the support element 210 can be determined by Fig. 6A The distance D in the radial direction shown is defined. The distance may be additionally or alternatively defined by the distance y1 between the distal end surface 211 of the support element 210 and the upper surface 221 of the first sealing member 220. This may be related to Figure 4 The distance y referred to in is the same as the distance y described above. Both distances affect how the substrate W interacts with each of these components during the unloading process.

[0115] Distance x1 can be within the range defined above for x. Distance x is the full length of the first sealing member 220. Additionally or alternatively, distance x2 can be within the range defined above for x. Distance x2 is the length of the upper surface 221 of the first sealing member 220. In other words, distance x2 is the length of the first sealing member 220 in the radial direction minus the length of the contact area 222. It may be beneficial for x2 to be higher than a certain value. Upper surface 221 provides the following functions: limit the gas / fluid radially inward of the first sealing member 220, and / or provide a low pressure area between the first sealing member 220 and the second sealing member 240, and / or provide a pressure drop radially inward from the first sealing member 220, therefore, the portion of upper surface 211 (having length x2) should be long enough to enable the first sealing member 220 to provide this function.

[0116] As described above, the coating layer 224 may be provided on the upper surface of the first sealing member 220. Figure 6B As shown, the coating 224 may be provided only on the contact region 222 where it may have the greatest effect. Thus, the coating 224 may be formed as part of the first sealing member 220 and may form the contact region 222 as described above and below.

[0117] In one embodiment, the profile may include a plurality of linear portions from the upper surface 221 of the first sealing member 220 to the radially outer edge 223 of the first sealing member 220. Fig. 7A , 7BIn one embodiment, the shape of the profile may be curved from the upper surface 221 of the first sealing member 220 to the radially outer edge 223 of the first sealing member 220. Fig.7D , 7E Additionally or alternatively, the outer edge of the first sealing member 220 may be rounded. This may be a rounded chamfer on the outer edge forming the contact area 222. The shape of the profile may be a portion of an ellipse or a circle. For example, the shape of the profile may be Fig.7D The shape of the contour can be as follows: Figure 7F and 7G The substantially stepped shape shown. Any shape that provides multiple contact points will reduce the local stress on the substrate W compared to a single point contact in cross section. The substrate W may contact the contact area 222 via a line contact, for example, when the edge is bent, there are more than a single contact point between the substrate W and the first sealing member 220, so that a contact line can be seen in the cross section. A shape with multiple discrete contact points (rather than line contact) will generally have a smaller total contact area and will wear faster. Figures 7A-7G The shapes shown in are examples of shapes that may be particularly advantageous in the case of specific substrates and / or systems and / or substrate unloading arrangements / sequences. Some of these shapes may have improved manufacturability and / or have an improved effect on the properties of the substrate W used, such as reducing the warpage of the substrate W.

[0118] It is beneficial to make the surface of the contact region 222 as smooth as possible. This reduces local stress on the lower surface of the substrate W. Thus, the contact region 222 may be configured to reduce friction between the substrate W and the first sealing member 220 when they interact. For example, the contact region 222 may be polished.

[0119] Fig. 6A and 7A -7G means that the contact region 222 can provide a contact area between the substrate W and the first sealing member 220. This is beneficial because it distributes the force applied to the first sealing member 220 and the substrate W, and means that local stress is reduced to reduce or prevent the formation of scratches on the lower surface of the substrate W, that is, to reduce or prevent damage to the lower surface of the substrate W. The contact area can be provided by multiple discrete contact points or line contacts in cross section.

[0120] Despite Figures 7A-7G The various profiles shown are not depicted, but any sealing member having these profiles may have a coating 224 as described above.

[0121] The first sealing member 220 is configured to surround a plurality of support elements 210 and is positioned radially outward of the plurality of support elements 210, meaning that all support elements 210 are radially inward of the first sealing member 220 in a plane. Thus, the first sealing member 220 may form an outermost contact point with the lower surface of the substrate W during loading and / or unloading. This allows for reduced wear on the support elements 210 as described above. The first sealing member 220 may surround the support elements 210 as a discrete member surrounding all support elements 210 in a plane, for example, the first sealing member 220 may be circular in a plane. The first sealing member 220 may not have a uniform cross-section and therefore, as Figure 4 -6. Figures 7A-7G , Figure 8 or Fig. 9 The shape of the first sealing member 220 shown may be different. The first sealing member 220 may optionally have gaps, such that the first sealing member 220 may be provided by a plurality of discrete members surrounding all of the support elements 210.

[0122] Due to the liquid close to this part of the system, the space between the lower surface of the substrate W and the body 201 of the substrate holder 200 may have a humid atmosphere. The disadvantage of a humid atmosphere is that oxidation of the support element 210 may occur. Oxidation of the support element 210 is harmful because it reduces the achievable flatness of the substrate W supported by the support element 210. The substrate holder 200 may include at least one extraction opening 230 formed in the body 201 for extracting fluid from between the body surface 202 and the substrate W into the body 201. The at least one extraction opening 230 may be part of a sealing mechanism. The extraction opening 230 as described below may be provided to help avoid having a humid atmosphere between the body surface 202 and the substrate W.

[0123] At least one extraction opening 230 may be arranged radially inward of the first sealing member 220 and adjacent to the first sealing member 220. Thus, there may be no other features such as a support element 210 between the at least one extraction opening 230 and the first sealing member 220. The extraction opening 230 may be connected to a low pressure source. Therefore, any liquid reaching the extraction opening 230 may be extracted through the body 201. This means that the liquid is restricted from further entering the space between the body surface 202 and the substrate W. For example, when there is no liquid to be extracted, the extraction opening 230 is also capable of extracting gas. A mixture of liquid and gas may be extracted through the extraction opening 230. At least one extraction opening 230 may be used to help provide the above-mentioned pressure drop and / or low pressure area.

[0124] At least one extraction opening 230 may be formed by a plurality of openings. The extraction openings 230 may be spaced apart from each other around the first sealing member 220. The extraction openings 230 may be discrete openings in the body surface 202. Alternatively, the extraction openings 230 may be grooves formed in the body surface 202. Alternatively, the grooves may be formed in the body surface 202 of the extraction opening 230, and may be exposed from the body 202 at the bottom of the grooves. The grooves may be segmented, with one or more openings in each segment. These segments may be considered as a plurality of recesses.

[0125] By connecting at least one extraction opening 230 to underpressure, liquid that does flow to the edge of the substrate W can be removed through said extraction opening 230. Once the edge of the substrate W is no longer covered by liquid, the lower surface of the substrate W is dried while the liquid is removed.

[0126] As described above, the substrate holder 200 may additionally include a second sealing member 240. Figure 4 , Figure 5 , Fig. 6A , Figure 6B , Figure 8 and Fig. 9 A second sealing member 240 is depicted, but this sealing member is optional and may not be provided with the first sealing member 220. The second sealing member 240 may be positioned radially inward of at least one extraction opening 230 (if provided). The second sealing member 240 may be positioned radially outward of the support element 210. The second sealing member 240 may be configured to surround or enclose at least one support element 210. Thus, all support elements 210 may be located radially inward of the second sealing member 240. Alternatively, at least one of the support elements 210 may be located radially outward of the second sealing member 240. In other words, the second sealing member 240 may be located radially inward of one or more support elements 210. For example, at least the radially outermost support element 210 may be positioned between the first sealing member 220 and the second sealing member 240. At least the radially outermost support element 210 may be arranged alternately with at least one extraction opening 230 in a line around the second sealing member 240.

[0127] As a supplement or alternative to the embodiments described above, the substrate holder 200 may include at least one additional member 250. The additional member 250 may have a contact area 252 configured to contact the substrate W during loading or unloading of the substrate W. The contact area 252 of the additional member 250 may be similar to the contact area 222 of the first sealing member 220 and have similar characteristics as described above for the contact area 222 of the first sealing member 220. In addition to the above-mentioned sealing unit / first sealing member 220, the additional member 250 may also be provided. In this embodiment, both the first sealing member 220 and the additional member 250 may be configured to contact the substrate W during loading and unloading of the substrate W. The additional member 250 may have a third height, which is less than the first height. In other words, the support element 210 may be higher than the additional 250.

[0128] The at least one further member 250 may be referred to hereinafter as further member 250, but it should be understood that reference to a further member may also include a plurality of further members. Thus, further member 250 may be formed from a plurality of separate parts or protrusions.

[0129] The further member 250 may provide a similar support function as the first sealing member 220 described above. Thus, the further member 250 may be configured to contact the substrate W during loading and / or unloading of the substrate W. By adding the further member 250 radially outwardly of the at least one support member 210, damage to the at least one support member 210 may be reduced or prevented. The further member 250 may act as a sacrificial burl / region.

[0130] In more detail, the substrate holder 200 may include a further member 250 protruding from the body surface 202 and having an upper surface 251. At least one further member 250 may be positioned radially outwards of the first sealing member 220 and surround the first sealing member. The upper surface 251 of the further member 250 may have a contact area 252 configured to contact the substrate W during loading and / or unloading of the substrate W. The contact area 252 of the further member 250 is located at a sufficient distance from the plurality of support elements 210 so that during loading and / or unloading of the substrate W, the force applied by the substrate W to the further member 250 is greater than the force applied by the substrate W to the plurality of support elements 210.

[0131] The further component 250 may include a coating 254 as described above. Thus, the coating may be formed of diamond-like carbon (DLC, such as a-CH), diamond, silicon carbide (such as SiSiC or SiC), boron nitride (BN) or boron nitride carbon (BCN). The coating 254 may form an upper surface 251 of the further component 250, and the contact area 252 of the further component 250 may be located on the coating 254. The coating 254 may have other characteristics as described above with respect to the sealing component coating 224 and / or the support component coating 214, such as thickness, etc. The coating 254 of the further component 250 may be further referred to as a further component coating.

[0132] Coating 254 as Figure 8 However, without the coating 254 , the further framework 250 may be provided in combination with the first sealing member 220 , as described above. The coating 254 of the further member 250 may be provided only on the contact area 252 of the further member 250 .

[0133] In another embodiment, the substrate holder 200 may include an alternative sealing member 260 and the additional member 250. The alternative sealing member 260 may replace the first sealing member 220 described above. In this embodiment, only the additional member 250 may have a contact area 252 configured to contact the substrate W during loading and / or unloading of the substrate W. In other words, in this embodiment, the alternative sealing member 260 is not configured to contact the substrate W during loading and / or unloading of the substrate W as in the embodiments described above. For example, the alternative sealing member 260 may be positioned so that it does not contact the substrate W during loading or unloading, for example, the alternative sealing member 260 may be located too far radially inward and does not contact the substrate W during loading and / or unloading. Thus, the alternative sealing member 260 may provide a seal, for example, by reducing or affecting the gas / fluid flow as described above with respect to the first sealing member 220, but does not contact the substrate W during loading or unloading, as done by the first sealing member 220.

[0134] In more detail, the substrate holder 200 includes a body 201, a plurality of support elements 210, a sealing unit and at least one additional member 250. The body 201 has a body surface 202. A plurality of support elements 210 protrude from the body surface 202. Each support element 210 may have a distal end surface 211 configured to support the substrate W and a first height. The sealing unit may be configured to restrict the flow or passage of liquid and / or gas radially inward through the sealing unit between the substrate W and the body surface 202. The sealing unit may include a first sealing member 220 protruding from the body surface 202. The first sealing member 220 may have a second height less than the first height. The first sealing member 220 may be positioned radially outward of the plurality of support elements 210 and surround the plurality of support elements. At least one additional member 250 protrudes from the body surface 202 and has an upper surface 251. At least one additional member 250 may be positioned radially outward of the plurality of support elements 210 and surround the plurality of support elements. Additionally, at least one further member 250 may be positioned radially outward of the sealing unit and surround the sealing unit. At least one further member 250 may include a coating 254, which forms an upper surface 251 of the further member 250. The coating 254 may have a contact area 252 configured to contact the substrate W during loading and / or unloading of the substrate W. The coating 254 may be made of diamond-like carbon (DLC, such as a-CH), diamond, silicon carbide (such as SiSiC or SiC), boron nitride (BN) or boron nitride carbon (BCN). The position of the contact area 252 of the further member 250 may be arranged at a sufficient distance from the plurality of support elements 210, so that during loading and / or unloading of the substrate W, the force applied by the substrate W to the further member 250 is greater than the force 210 applied by the substrate W to the plurality of support elements.

[0135] In this embodiment, the sealing unit may include an alternative sealing member 260 as described above. The alternative sealing member 260 may protrude from the main body surface 202. The alternative sealing member 260 may be radially outward of a plurality of support elements 210. The alternative sealing member 260 may surround a plurality of support elements 210. The alternative sealing member 260 may work in the same manner as the above-mentioned first sealing member 220. However, in this embodiment, the alternative sealing member 260 may be configured so that it is generally not in contact with the substrate W during loading and / or unloading. The sealing unit may include a second sealing member 240 as described above. Thus, the second sealing member 240 may protrude from the main body surface and may be positioned radially outward of the alternative sealing member 260.

[0136] In any of the embodiments described, the further member 250 may have similar properties to the first sealing member 220 described above. Fig. 6A ,6B 7A-7G, in addition, the member 250 may have a contact area, which may have a contact area as described above with respect to Fig. 6A , Figure 6B and FIG. 7A to FIG. 7G In more detail, in a cross section through the further component 250 in the radial direction, the profile of the contact area 252 of the further component 250 may have a certain shape, which is configured so that during loading and / or unloading of the substrate W, the substrate W contacts the further component 250 via at least two different points of the profile. The further component 250 may include a coating 254 only on the contact area 252 having the profile, such as for example Figure 6B The first sealing member 220 shown in FIG.

[0137] In addition, the member 250 can be arranged in the shape of a continuous loop. In other words, the member 250 can be circular on a plane, or more specifically, annular or ring-shaped. Thus, the member 250 can have an annular shape. The member 250 can include multiple sections, and can be optionally a segmented loop. In the segmented loop, multiple additional member parts can be present, and there is a gap between each adjacent additional member part. The additional member part can be called a radial spoke. The gap between adjacent additional member parts can be the same length as any one or both of the adjacent parts, or smaller than the length of any one or both of the adjacent parts. In other words, the distance between each additional member part can be equal to or less than the width of one or both of the adjacent additional member parts. At least one of the gaps between adjacent additional member parts (i.e., the intervals between adjacent parts) can be about tens or hundreds of microns. At least one of the gaps between adjacent additional member parts can be approximately 10 microns narrow. At least one of the gaps can be between 0.5 and 5 mm. Some or all of the gaps can have these sizes. Providing a small gap may be advantageous because any contaminants, for example from the interaction between the further member 250 and the underside of the substrate W, may be trapped in the gap while still providing a relatively large contact area.

[0138] The additional member 250 can be provided by a row of multiple individual knobs or protrusions, which are spaced apart from each other to form an annular shape on a plane. In other words, the additional member 250 can include multiple additional support elements. For example, the individual knobs or protrusions can have a diameter of approximately 100 to 1000 microns. The distance from the middle of a knob or protrusion to the middle of an adjacent knob or protrusion can be approximately 1 to 3 mm. The upper surface 251 of the additional member 250 can be slightly rounded or polished, as described above with respect to the first sealing component 220, to reduce the wear of the additional component 250.

[0139] The further member 250 may have a height (third height) that is smaller than the height of the at least one support member 210. This means that the further member 250 may bear the load during loading and unloading of the substrate W. However, during use, such as during exposure of the substrate W, the further member 250 may not be in contact with the substrate W. For the first sealing member 220, the distance between the further member 250 and the at least one support member 210 may be as follows: Figure 4 Optimize as described.

[0140] The position of the contact area 252 of the further component 250 relative to the support element 210 can be controlled in various ways. Fig. 9 As shown, the main dimensions relate to the distance between the radially outer edge 212 of the distal end face 211 of said radially outermost support element 210 and the outer upper edge of the upper surface 251 of the further member 250. Said dimensions relate to these specific parts of the further member 250 and the support element 210, as these parts are the parts of these components that will be in contact with the lower surface of the substrate W during loading and / or unloading of the substrate W.

[0141] The distance may be defined by a radial distance D. The distance may additionally or alternatively be defined by a distance y between the distal end surface 211 of the support element 210 and the upper surface 251 of the further member 250. Both distances will affect how the substrate W interacts with each of these components during loading and / or unloading.

[0142] In this example, the contact area 252 is shown as an edge contact point in cross section. Thus, in this embodiment, the contact area 252 is formed by the same contact point around the circumference of the further member 250. This contact area 252 can be similar to the contact point for Figure 4 The contact area of ​​the first sealing member 220 is shown. The position of the contact area 252 relative to the support element 210 is configured to reduce wear of the support element 210 during unloading of the substrate W.

[0143] In an embodiment, the radial distance D from the radially outer edge 212 of the distal end surface 211 to the contact area 252 is greater than 1000 microns, and preferably greater than 1500 microns. The radial distance D is preferably between about 1000 and 3000 microns, i.e. 1 to 3 mm. This means that the contact area 252 can be far enough away from the support element 210 to reduce the contact between the support element 210 and the substrate W during loading and / or unloading. Additionally or alternatively, the height difference between the radially outermost support element 210 and the further member 250 is between about 0.5 microns and 5 microns, such as Fig. 9y in the figure. Preferably, the height difference is greater than or equal to 3 micrometers to reduce the possibility that the further member 250 contacts the underside of the substrate W during exposure of the substrate W. The height difference between the radially outermost support element 210 and the further member 250 is the distance between the upper surface of the further member 20 and the distal end surface 211 in the y direction, wherein the y direction is orthogonal to the plane including the radial direction. Having a height difference can also reduce contact between the support element 210 and the substrate W during loading and / or unloading.

[0144] Providing the contact area 252 at such a distance means that during loading and / or unloading of the substrate W, the substrate W will have a greater interaction with the further member 250 rather than the radially outermost support element 210. In practice, this means that the further member 250 is used as a sacrificial wear area. This may result in a significant reduction in the wear of the outermost support element 210. The distance between the radially outer edge 212 and the contact area 252 in the radial and / or y direction may be optimized to minimize the friction between the outermost support element 210 and the substrate W during loading and / or unloading of the substrate W. The optimal values ​​of the distance D and the distance y may vary depending on the substrate holder 200 and / or the substrate W and / or the application on which the substrate W is applied.

[0145] As indicated above, the substrate holder 200 may include at least one support element 210 between the first sealing member 220 and the second sealing member 240. Fig.10 Thus, the outermost support element 210 may be disposed adjacent to the first sealing member 220 and the second sealing member 240. Therefore, the second sealing member 240 may only surround a portion of the support element 210 instead of the entirety.

[0146] In this example, as Figure 4 For the first sealing member 220 depicted in FIG. 1 , the distance between the contact area 222 and the support element 210 may be determined by Fig.10 This can be defined by the radial distance D shown in Figure 4 The distance D referred to in the above description is the same value / range. The distance may be additionally or alternatively defined by the distance y between the distal end surface 211 of the support element 210 and the upper surface 221 of the first sealing member 220. This may be Figure 4 The distance y referred to in and described above is the same value / range. The distance x is the full length of the first sealing member 220. This can be Figure 4 The same values / ranges as the distances x referred to in and described above. All of these distances will affect how the substrate W interacts with each of these components during the unloading process.

[0147] A plurality of support elements 210 may be provided between the first sealing member 220 and the second sealing member 240. Optionally, at least one extraction opening 230 may also be provided. For example, the support elements 210 and the extraction openings 230 may alternate in the space between the first sealing member 220 and the second sealing member 240. In other words, Fig.10 A cross section through a portion of the substrate holder 200 is shown through the outermost support element 210 between the first sealing member 220 and the second sealing member 240, however, at a different radial position, a similar cross section may show the extraction opening 230 between the first sealing member 220 and the second sealing member 240, as shown in FIG. Figure 4 shown.

[0148] At least one outermost support element 210 may also be disposed in a similar position in other embodiments. Figure 8 Set in, or Fig. 9 When disposed between the alternative sealing member 260 and the second sealing member 240, the outermost support element 210 may be disposed between the first sealing member 220 and the second sealing member 240. These members may include contact areas 222, 252 and / or coatings 254, as described in any of the embodiments or variations described above.

[0149] As described above, the substrate holder 200 may be configured to control the pressure between the body 201 and the substrate W when the substrate W is unloaded. This can be done in various ways, and any known method / system can be used. The present invention may include a lithographic apparatus as described in any of the examples of the above variations. The lithographic apparatus may include a substrate holder 200 configured to support the substrate according to any of the embodiments or variations.

[0150] Although specific reference may be made herein to the use of lithographic equipment in IC manufacturing, it should be understood that the lithographic equipment described herein may have other applications. Possible other applications include the manufacture of integrated optical systems, guidance and detection modes for magnetic domain memory, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads, etc.

[0151] Although embodiments of the present invention may be specifically mentioned herein in the context of lithographic equipment, embodiments of the present invention may be used in other equipment. Embodiments of the present invention may form part of a mask inspection equipment, a metrology equipment, or any equipment that measures or processes an object such as a wafer (or other substrate) or a mask (or other graphic device). These equipment are generally referred to as lithographic tools. Such lithographic tools may use vacuum conditions or ambient (non-vacuum) conditions.

[0152] Although specific reference may have been made above to the use of embodiments of the invention in the context of optical lithography, it will be appreciated that the invention is not limited to optical lithography and may be used in other applications, such as imprint lithography, where the context permits.

[0153] The accompanying drawings are intended to illustrate the various features described above. The accompanying drawings are not drawn to scale. The relative width and height of different features may vary relative to other features. For example, the additional member 250 is shown to be narrower than the first sealing member 220 and the second sealing member 240. However, the additional member 250 can be the same width (i.e., the same length in the x-direction), or can be wider (i.e., having a greater length in the x-direction).

[0154] Although specific embodiments of the present invention have been described above, it should be appreciated that the present invention may be practiced in other ways than those described. The above description is intended to be illustrative rather than restrictive. Therefore, it will be appreciated by those skilled in the art that modifications may be made to the described invention without departing from the scope of the claims set forth below.

Claims

1. A substrate holder configured to support a substrate for use in a lithographic apparatus, the substrate holder comprising: a body having a body surface; a plurality of support elements protruding from the body surface, wherein each support element has a distal end surface configured to support the substrate and a first height; a sealing unit including a first sealing member protruding from a surface of the body, the first sealing member having an upper surface and a second height less than the first height and positioned radially outward of the plurality of support elements and surrounding the plurality of support elements, the upper surface having a contact area configured to contact the substrate during substrate loading and / or unloading; and wherein the contact area is located at a sufficient distance from the plurality of support elements so that during loading and / or unloading of the substrate, a force applied by the substrate to the first sealing member is greater than a force applied by the substrate to the plurality of support elements; and Therein, in a cross section through the first sealing member in a radial direction, a profile of the contact area has a shape configured such that during loading and / or unloading of the substrate the substrate contacts the first sealing member via at least two different points of the profile.

2. The substrate holder according to claim 1, wherein The radial distance is greater than 1500 microns.

3. The substrate holder according to claim 1, wherein The length of the first sealing member in the radial direction is greater than 300 micrometers.

4. The substrate holder according to claim 3, wherein: The length of the first sealing member in the radial direction is greater than 500 micrometers.

5. The substrate holder according to claim 1, wherein In a cross section through the first sealing member in a radial direction, the profile of the contact area has a shape configured such that during loading and / or unloading of the substrate the substrate contacts the first sealing member via at least two different points of the profile.

6. The substrate holder according to claim 1 , further comprising at least one further member protruding from a surface of the main body and having an upper surface, the at least one further member being located radially outward of the sealing unit and surrounding the sealing unit, the upper surface of the further member having a contact area configured to contact with the substrate during loading and / or unloading of the substrate, in, The contact area of ​​the further member is positioned at a sufficient distance from the plurality of support elements so that during loading and / or unloading of the substrate, the force applied by the substrate to the further member is greater than the force applied by the substrate to the plurality of support elements.

7. The substrate holder according to any one of claims 1 to 6, wherein: The multiple support elements, the first sealing member, or both include a coating made of diamond-like carbon, diamond, silicon carbide, boron nitride or boron nitride carbon, which forms the distal end faces of the multiple support elements and / or forms the upper surface of the first sealing member, and the contact area of ​​the first sealing member is located on the coating.

8. The substrate holder according to claim 7, wherein: The thickness of the coating is between 0.2 μm and 2 μm.

9. The substrate holder according to claim 8, wherein: The thickness is between 0.2 μm and 1.5 μm.

10. The substrate holder according to claim 9, wherein The thickness is between 0.2 μm and 1 μm.

11. The substrate holder according to claim 6, wherein: The at least one further component comprises a coating made of diamond-like carbon, diamond, silicon carbide, boron nitride or silicon boron nitride, wherein the coating forms an upper surface of the further component and the contact area of ​​the further component is located on the coating of the further component.

12. The substrate holder according to claim 11, wherein The thickness of the coating is between 0.2 μm and 2 μm.

13. The substrate holder according to claim 12, wherein: The thickness is between 0.2 μm and 1.5 μm.

14. The substrate holder according to claim 13, wherein: The thickness is between 0.2 μm and 1 μm.

15. The substrate holder according to any one of claims 1 to 6, wherein: The contact area is located adjacent to the radially outer edge of the first sealing member and the radial distance from the radially outer edge of the distal end face to the contact area is greater than 1000 microns and / or the height difference between the radially outermost support element and the first sealing member is between 2 microns and 8 microns.

16. The substrate holder according to any one of claims 1 to 6, wherein the substrate holder further comprises: At least one extraction opening is formed in the body for extracting fluid from between the body surface and the substrate into the body when the substrate is supported by the plurality of support elements, and the at least one extraction opening is arranged outside the plurality of support elements and near the radial inner side of the first sealing member.

17. A substrate holder for use in a lithographic apparatus and configured to support a substrate, the substrate holder comprising: a body having a body surface; a plurality of support elements protruding from the body surface, wherein each support element has a distal end surface configured to support the substrate and a first height; a sealing unit including a first sealing member protruding from a surface of the body, the first sealing member having a second height smaller than the first height and positioned radially outward of the plurality of support elements and surrounding the plurality of support elements, at least one further member protruding from the body surface and having an upper surface and having a third height less than the first height, the at least one further member being positioned radially outward of the sealing units and surrounding the plurality of sealing units, the at least one further member comprising a coating forming an upper surface of the further member, the coating having a contact area configured to contact with a substrate during loading and / or unloading of the substrate; and wherein the contact area of ​​the further member is located at a sufficiently sufficient distance from the plurality of support elements such that during loading and / or unloading of the substrate, a force applied by the substrate to the further member is greater than a force applied by the substrate to the plurality of support elements; and Therein, in a cross section through the further member in a radial direction, a profile of a contact region of the further member has a shape configured such that during loading and / or unloading of the substrate the substrate contacts the further member via at least two different points of the profile.

18. The substrate holder according to claim 17, wherein The thickness of the coating is between 0.2 μm and 2 μm.

19. The substrate holder according to claim 18, wherein The thickness is between 0.2 μm and 1.5 μm.

20. The substrate holder according to claim 19, wherein The thickness is between 0.2 μm and 1 μm.

21. The substrate holder of claim 17, wherein the substrate holder further comprises: At least one extraction opening is formed in the body for extracting fluid from between the body surface and the substrate into the body when the substrate is supported by the plurality of support elements, and the at least one extraction opening is arranged outside the plurality of support elements and near the inner side of the first sealing member.

22. The substrate holder according to any one of claims 17 to 21, wherein: The further member has a ring shape and comprises a plurality of segments.

23. The substrate holder according to any one of claims 17 to 21, wherein: The further means comprises a plurality of further support elements.

24. The substrate holder according to any one of claims 17 to 21, wherein the coating is made of diamond-like carbon, diamond, silicon carbide, boron nitride or silicon boron nitride.

25. A substrate holder configured to support a substrate for use in a lithographic apparatus, the substrate holder comprising: a body having a body surface; a plurality of support elements protruding from the body surface, wherein each support element has a distal end surface configured to support the substrate and a first height; a sealing unit including a first sealing member protruding from a surface of a body, the first sealing member having an upper surface and a second height smaller than the first height and positioned radially outward of the plurality of support elements and surrounding the plurality of support elements, and the upper surface having a contact area configured to contact the substrate during substrate loading and / or unloading, and Therein, in a cross section through the first sealing member in a radial direction, the profile of the contact area has a shape configured such that during loading and / or unloading of the substrate, the substrate contacts the first sealing member via at least two different points of the profile.

26. A substrate holder according to claim 1, 17 or 25, wherein: The shape of the profile is linear from an upper surface of the first sealing member to a radially outer edge of the first sealing member.

27. The substrate holder according to claim 26, wherein A linear profile from an upper surface of the first sealing member to a radially outer edge of the first sealing member has a negative gradient of between 0.15 microns / mm and 3 microns / mm relative to the upper surface of the first sealing member.

28. The substrate holder of claim 1, 17 or 25, wherein: The shape of the profile includes a plurality of linear portions from an upper surface of the first sealing member to a radially outer edge of the first sealing member.

29. The substrate holder of claim 1, 17 or 25, wherein: The shape of the profile is substantially stepped.

30. The substrate holder of claim 1, 17 or 25, wherein: The shape of the profile curves from an upper surface of the first sealing member to a radially outer edge of the first sealing member.

31. The substrate holder of claim 30, wherein: The shape of the contour is an ellipse or a portion of a circle.

32. A substrate holder according to any one of claims 1-6, 17-21 and 25, wherein the sealing unit includes a second sealing member protruding from the main body surface and positioned radially inward of the first sealing member, the second sealing member being configured to restrict the flow or passage of liquid radially inward through the second sealing member between the substrate and the main body surface, and / or wherein the first sealing member is configured to provide a pressure drop radially inward of the first sealing member relative to the pressure in the radially outer region of the sealing unit.

33. The substrate holder of claim 32, wherein: The first sealing member is configured to provide a low pressure region between the first sealing member and the second sealing member.

34. The substrate holder according to any one of claims 1-6, 17-21 and 25, wherein The first sealing member is configured to provide a pressure drop radially inwardly from the first sealing member relative to a pressure in a region radially outwardly of the sealing unit.

35. The substrate holder of any one of claims 1-6, 17-21 and 25, further comprising at least one extraction opening formed in the body for extracting fluid from between the body surface and the substrate into the body, the at least one extraction opening being arranged radially inwardly and adjacent to the first sealing member, and / or wherein, The substrate holder is configured to control pressure between the body and the substrate when the substrate is loaded and / or unloaded.

36. The substrate holder according to any one of claims 1-6, 17-21 and 25, wherein The substrate holder is configured to control pressure between the body and the substrate when the substrate is loaded and / or unloaded.

37. A lithographic apparatus comprising a substrate holder according to any one of claims 1-36 configured to support the substrate.

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