Fluid processing system, method and lithographic apparatus

Abstract

Disclosed herein is a fluid processing system for a lithographic apparatus wherein the fluid processing system is configured to confine immersion fluid in a liquid confinement space between a portion of a projection system in the lithographic apparatus and a surface of a substrate, a fluid treatment system whereby a radiation beam projected from the projection system is able to illuminate the surface of the substrate by passing through the immersion fluid, the fluid treatment system comprising a meniscus control surface for controlling movement of a meniscus of the immersion fluid; wherein, in a first operating state, the meniscus control surface is configured to maintain a meniscus of the immersion fluid substantially stationary between the meniscus control surface and the surface of the substrate; and wherein, in a second operating state, the meniscus control surface is configured to allow the movement of the meniscus of the immersion fluid.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to European patent application 22183583.8 filed on July 7, 2022, and the entire contents of that application are incorporated herein by reference. Technical Field

[0003] The present invention relates to a fluid processing system and a device manufacturing method. The present invention also relates to a photolithography apparatus. Background Art

[0004] A lithographic apparatus is a machine constructed to apply a desired pattern to a substrate. For example, a lithographic apparatus can be used in the manufacture of integrated circuits (ICs). For example, a lithographic apparatus can project a pattern (also referred to as a "design layout" or "design") of a patterned device (e.g., a mask) onto a layer of radiation-sensitive material (resist) disposed on a substrate (e.g., a wafer). Known lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing the entire pattern to the target portion at once, and so-called scanners, in which each target portion is irradiated by scanning the pattern with a radiation beam in a given direction (the "scanning" direction) while synchronously scanning the substrate parallel or antiparallel to that direction.

[0005] As semiconductor manufacturing processes continue to improve, the size of circuit elements continues to decrease, while the number of functional elements (such as transistors) per device has steadily increased for decades, a trend often referred to as "Moore's Law." To keep up with Moore's Law, the semiconductor industry is chasing technologies that can create smaller and smaller features. To project a pattern onto a substrate, a lithography device can use electromagnetic radiation. The wavelength of this radiation determines the minimum size of the features that can be patterned on the substrate. Typical wavelengths currently in use are 365nm (i-line), 248nm, 193nm, and 13.5nm.

[0006] Further improvements in resolution of smaller features can be achieved by providing an immersion fluid with a relatively high refractive index, such as water, on the substrate during exposure. The effect of the immersion fluid is to enable imaging of smaller features because the wavelength of the exposing radiation in the fluid is shorter than that in the gas. The effect of the immersion fluid can also be seen as increasing the effective numerical aperture (NA) of the system and also increasing the depth of focus.

[0007] The immersion fluid may be confined to a localized region between the projection system and the substrate of the lithographic apparatus by means of a fluid handling structure. The use of such an immersion fluid may result in the presence of droplets on the surface of the substrate. Such droplets may be a problem because they may cause dry spots on the substrate and because when the droplets strike the meniscus of the immersion liquid this may result in the formation of bubbles due to trapped gases in the immersion liquid. Bubbles in the immersion liquid may result in printing defects on the substrate. The likelihood of introducing such bubbles may be reduced by reducing the relative speed of the substrate, however this limits the throughput of the lithographic apparatus. Summary of the invention

[0008] It is an object of the present invention to provide a fluid handling system and method that takes steps to increase throughput and / or reduce defects on substrates.

[0009] According to a first aspect of the present invention, there is provided a fluid handling system for a lithographic apparatus, wherein the fluid handling system is configured to confine an immersion fluid in a liquid confinement space between a portion of a projection system in the lithographic apparatus and a surface of a substrate, whereby a radiation beam projected from the projection system can irradiate the surface of the substrate by passing through the immersion fluid, the fluid handling system comprising a meniscus control surface for controlling movement of a meniscus of the immersion fluid; wherein, in a first operating state, the meniscus control surface is configured to keep the meniscus of the immersion fluid substantially stationary between the meniscus control surface and the surface of the substrate; and wherein, in a second operating state, the meniscus control surface is configured to allow movement of the meniscus of the immersion fluid.

[0010] According to a second aspect of the present invention, there is provided a fluid handling system for a lithographic apparatus, wherein the fluid handling system is configured to confine an immersion fluid in a liquid confinement space between a portion of a projection system in the lithographic apparatus and a surface of a substrate, whereby a radiation beam projected from the projection system can irradiate the surface of the substrate by passing through the immersion fluid, the fluid handling system comprising: a meniscus liquid surface control surface and an extraction member, both of which are configured to extract the immersion fluid; wherein the meniscus liquid surface control surface is configured to support a meniscus of the immersion fluid between the meniscus liquid surface control surface and the surface of the substrate in a first operating state and a second operating state; in the first operating state, the meniscus is fixed to the meniscus liquid surface control surface; and in the second operating state, the meniscus can move along the meniscus liquid surface control surface.

[0011] According to a third aspect of the present invention, there is provided a fluid handling system for a lithographic apparatus, wherein the fluid handling system is configured to confine an immersion fluid in a liquid confinement space between a portion of a projection system in the lithographic apparatus and a surface of a substrate, whereby a radiation beam projected from the projection system can irradiate the surface of the substrate by passing through the immersion fluid, the fluid handling system comprising: a first extraction member and a second extraction member, both of which are configured to extract the immersion fluid; and a meniscus control surface, which is between the first extraction member and the second extraction member and is configured to extract the immersion fluid; wherein the meniscus control surface is configured to support a meniscus of the immersion liquid between a surface of the meniscus control surface and the surface of the substrate.

[0012] According to a fourth aspect of the present invention, there is provided a lithographic apparatus comprising the fluid handling system according to the first to third aspects.

[0013] According to a fifth aspect of the present invention, there is provided a device manufacturing method in a lithography apparatus, the lithography apparatus having a substrate holder configured to hold a substrate, a projection system configured to project a radiation beam onto a substrate held by the substrate holder, and a fluid handling system according to any one of the first to third aspects, the method comprising: using the fluid handling system to confine an immersion fluid in a space between at least a portion of the fluid handling system and a surface of the substrate; projecting a patterned radiation beam onto the substrate through the immersion fluid in the space; supporting a curved liquid surface of the immersion fluid between a curved liquid surface control surface or a damper of the fluid handling system and the substrate; and moving the substrate in a scanning direction substantially perpendicular to a propagation direction of the radiation beam; wherein, in a first operating state, the curved liquid surface control surface is configured to keep the curved liquid surface of the immersion fluid substantially stationary between the curved liquid surface control surface and the surface of the substrate; and wherein, in a second operating state, the curved liquid surface control surface is configured to allow the curved liquid surface of the immersion fluid to move relative to the curved liquid surface control surface.

[0014] According to a sixth aspect of the present invention, there is provided a fluid handling system for a lithography apparatus, wherein the fluid handling system is configured to confine an immersion fluid in a liquid confinement space between a portion of a projection system in the lithography apparatus and a surface of a substrate, whereby a radiation beam projected from the projection system can irradiate the surface of the substrate by passing through the immersion fluid, the fluid handling system comprising an electrowetting structure; wherein: the electrowetting structure comprises one or more electrodes, the one or more electrodes being arranged to apply an electrowetting effect to at least a portion of a surface of the fluid handling system facing the substrate; and the one or more electrodes of the electrowetting structure are controllable to change the contact angle and / or contact line of the curved liquid surface of the immersion fluid.

[0015] According to a seventh aspect of the present invention, there is provided a lithography apparatus, comprising the fluid handling system according to the sixth aspect.

[0016] Further embodiments, features, and advantages of the present invention, as well as the structure and operation of the various embodiments, features, and advantages of the present invention are described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, wherein corresponding reference characters indicate corresponding parts, and wherein:

[0018] Figure 1 A schematic diagram of a photolithography apparatus is depicted;

[0019] Figure 2a , Figure 2b , Figure 2c and Figure 2d Two different versions of a fluid handling system are each depicted in cross-section, with different features shown on the left and right sides of each version, which features may extend around a complete circumference;

[0020] Figure 3a and Figure 3b schematically illustrates a portion of a known fluid handling system in respective first and second operating states;

[0021] Figure 4 schematically illustrates a portion of a fluid treatment system according to a first embodiment;

[0022] Figure 5 schematically illustrates a portion of a fluid treatment system according to a second embodiment;

[0023] Figure 6a and Figure 6b A portion of a fluid treatment system according to a third embodiment is schematically shown.

[0024] The features shown in the figures are not necessarily drawn to scale, and the sizes and / or arrangements depicted are not limited. It should be understood that the drawings include optional features that may not be essential to the present invention. In addition, not all features of the device are depicted in each of the figures in the drawings, and the figures may only show some of the components relevant to describing a particular feature. 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 nm, 248 nm, 193 nm, 157 nm 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 that corresponds to the pattern to be created in a target portion of the substrate. In this context, the term "light valve" may also be used. 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 includes an illumination system (also referred to as an illuminator) IL configured to condition a radiation beam B (e.g., UV radiation or DUV radiation), a mask support (e.g., a masking stage) MT configured to support a patterned device (e.g., a mask) MA and connected to a first positioner PM configured to accurately position the patterned device MA according to certain parameters, a substrate support (e.g., a substrate stage) WT configured to hold a substrate (e.g., a wafer coated with a resist) W and connected to a second positioner PW configured to accurately position the substrate support WT according to certain parameters, and a projection system (e.g., a refractive projection lens system) PS configured to project a pattern imparted to the radiation beam B by the patterned device MA onto a target portion C (e.g., including one or more dies) of the substrate W. A controller 500 controls the overall operation of the apparatus. The controller 500 may be a centralized control system or a system of multiple individual sub-controllers within various subsystems of the lithographic apparatus.

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

[0029] The term "projection system" PS as used herein should be broadly interpreted as including various types of projection systems, including refractive, reflective, catadioptric, anamorphic, magnetic, electromagnetic and / or electrostatic optical systems, or any combination thereof, depending on 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 a synonym for the more general term "projection system" PS.

[0030] The lithographic apparatus is of a type in which at least a portion of the substrate W may be covered by an immersion liquid having a relatively high refractive index (e.g. water) to fill an immersion space 11 between the projection system PS and the substrate W - this is also known as immersion lithography. More information on immersion technology is given in US 6,952,253, which is incorporated herein by reference.

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

[0032] In addition to the substrate support WT, the lithographic apparatus may also comprise a measuring table (not depicted in the figure). The measuring table is arranged to hold sensors and / or cleaning equipment. The sensors may be arranged to measure characteristics of the projection system PS or characteristics of the radiation beam B. The measuring table may hold a plurality of sensors. The cleaning equipment may be arranged to clean a part of the lithographic apparatus, for example a part of the projection system PS or a part of a system for providing immersion liquid. The measuring table 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) which is held on a mask support MT and is patterned by a pattern (design layout) present on the patterning device MA. After passing through the mask MA, the radiation beam B passes through a projection system PS which focuses the beam onto a target portion C of the substrate W. With the help of a second positioner 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 positioner PM and possibly another position sensor ( Figure 1 The patterned 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 as shown occupy dedicated target portions, they may be positioned in spaces between target portions. When the substrate alignment marks P1, P2 are positioned between target portions C, they are referred to as scribe lane alignment marks.

[0034] In order to illustrate the present invention, a Cartesian coordinate system is used. The 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. The rotation around the x-axis is called an Rx rotation. The rotation around the y-axis is called an Ry rotation. The rotation around the z-axis is called 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 and is only used for illustration. On the contrary, another coordinate system such as a cylindrical coordinate system can be used to illustrate the present invention. The direction 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 inserted into an immersion space 11 between the projection system PS of the apparatus (a patterned light beam is projected toward the substrate W by the projection system PS) and the substrate W. The immersion liquid covers at least a portion of the substrate W below the final element of the projection system PS. Thus, at least the portion of the substrate W that is subject to exposure is immersed in the immersion liquid.

[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 typically purified, and it may undergo additional processing steps before being supplied to the immersion space 11 as an immersion liquid. In addition to water as an immersion liquid, other liquids with a high refractive index may be used, for example: hydrocarbons, such as fluorinated hydrocarbons; and / or aqueous solutions. Furthermore, other fluids than liquids are also contemplated for use in immersion lithography.

[0037] In this specification, reference will be made to partial immersion in the description, wherein in use the immersion liquid is confined in an immersion space 11 between the final element 100 and a surface facing the final element 100. The facing surface is the surface of the substrate W or the surface of the support table (or substrate support WT) which is coplanar with the surface of the substrate W. (Note that, unless expressly stated otherwise, references to the surface of the substrate W hereinafter also refer to the surface of the substrate support WT in addition to or as an alternative to the surface of the substrate support WT; and vice versa). A fluid handling structure 12 present between the projection system PS and the substrate support WT serves to confine the immersion liquid in the immersion space 11. The immersion space 11 filled with the immersion liquid is smaller in plane than the top surface of the substrate W, and the immersion space 11 remains substantially stationary relative to the projection system PS, while the substrate W and the 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 an unconfined immersion system, the immersion liquid covers an area larger than the surface below the final element 100. The liquid outside the immersion space 11 is in the form of 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 that supplies immersion liquid to the immersion space 11, removes immersion liquid from the immersion space 11 and thereby confines immersion liquid in the immersion space 11. It includes functionality as part of a fluid supply system. The arrangement disclosed in PCT patent application publication number WO 99 / 49504 is an early fluid handling structure that includes conduits that supply or withdraw immersion liquid from the immersion space 11 and whose operation depends on relative movement of the stage below the projection system PS. In more recent designs, the fluid handling structure extends along at least a portion of the boundary of the immersion space 11 between the final element 100 of the projection system PS and the substrate support WT or substrate W so as to partially define the immersion space 11.

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

[0041] As a barrier member, the fluid handling structure 12 is a barrier to the flow of immersion liquid from the immersion space 11. As a liquid confinement structure, the structure confines the immersion liquid in the immersion space 11. As a sealing member, the sealing features of the fluid handling structure 12 form a seal to confine the immersion liquid in the immersion space 11. The sealing features may include an additional gas flow from an opening in the surface of the sealing member, 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 thus the fluid handling structure 12 may be referred to as a sealing member; such a sealing member 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 handling system. With reference to the above description, the features mentioned in this paragraph regarding the definition of fluid may be understood to include features regarding the definition of 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 from the projection system PS passes through an immersion liquid confined by a fluid handling structure 12 between the projection system PS and the substrate W. The projection system PS has a last lens element in the beam path that is in contact with the immersion liquid, i.e. the lens element in contact with the immersion liquid may be referred to as the "last lens element" or the "final element". The final element 100 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 100 and above the facing surface.

[0049] Figure 2a , Figure 2b , Figure 2c and Figure 2d The different features that may be present in variations of the fluid handling system are shown. Unless otherwise specified, these designs may be used with Figure 2a , Figure 2b , Figure 2c and Figure 2d The features described herein may be selected individually or in combination as shown in the figures or as desired. The figures depict different versions of the fluid treatment system, where different features are shown on the left and right sides, and these features may extend around the complete circumference. Thus, for example, the fluid treatment system may have the same features extending around the complete circumference. For example, the fluid treatment system may only have Figure 2a on the left side, or Figure 2a on the right side, or Figure 2b on the left side, or Figure 2b on the right side, or Figure 2c on the left side, or Figure 2c on the right side, or Figure 2d left side or Figure 2dAlternatively, the fluid handling system may be provided with any combination of features from these figures at different locations around the circumference. The fluid handling system may include a fluid handling structure 12 as described in the following variations.

[0050] Figure 2a A fluid handling structure 12 is shown around the bottom surface of the final element 100. The final element 100 has an inverted truncated cone shape. The truncated cone has a flat bottom surface and a conical surface. The truncated cone 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 a portion of the truncated cone. The fluid handling structure 12 has an inner surface facing the conical surface of the truncated cone. The inner surface and the conical surface may have complementary shapes. The top surface of the fluid handling structure 12 may be substantially flat. The fluid handling structure 12 may be assembled around the truncated cone shape of the final element 100. The bottom surface of the fluid handling structure 12 may be 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. Therefore, the bottom surface of the fluid handling structure 12 may be referred to as a surface facing the substrate W surface. The distance between the bottom surface and the facing surface may be in the range of 20 microns to 500 microns, desirably in the range of 70 microns to 200 microns.

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

[0052] Immersion liquid is supplied to the immersion 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 bottom surface of the fluid handling structure 12. The lower supply opening 23 may surround the path of the radiation beam B, and the lower supply opening may be formed by a series of openings in an array or a single slit. Immersion liquid is supplied to fill the immersion space 11 so that the flow through the immersion space 11 below the projection system PS is laminar. Supplying immersion liquid from the lower supply opening 23 also prevents bubbles from entering the immersion space 11. Such a supply of immersion liquid may act as a liquid seal.

[0053] The immersion liquid may be recovered from a recovery opening 21 formed in the inner surface. Recovery of the immersion liquid through the recovery opening 21 may be achieved by applying a negative pressure; recovery through the recovery opening 21 may be achieved due to the speed at which the immersion liquid flows through the immersion space 11; or recovery may be the result of both. From a plan view, 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 by an overflow recovery member 24 located on the top surface of the fluid handling structure 12. The functions of the supply opening 20 and the recovery opening 21 may be interchanged (i.e., the direction of flow of the liquid is reversed). This allows the direction of flow to be changed depending on 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 through a recovery opening 25 formed in the bottom surface of the fluid handling structure 12. The recovery opening 25 may be used to hold 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 serves 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 substantially single-phase flow. The recovery openings in the bottom surface may be a series of fixed openings 32 through which the immersion liquid is recovered. The fixed openings 32 may recover the immersion liquid in a two-phase flow.

[0055] Radially outwardly relative to the inner surface of the fluid handling structure 12 is optionally an air knife opening 26. Gas may be supplied at high velocity through the air knife opening 26 to assist in liquid confinement of the immersion liquid in the immersion space 11. The supplied gas may be humidified and it may contain a significant amount of carbon dioxide. Radially outwardly of the air knife opening 26 is a gas recovery opening 28 for recovering gas supplied through the air knife opening 26.

[0056] In the bottom surface of the fluid handling structure 12, ie in the fluid handling structure 12 facing the substrate W, there may be further openings, for example openings to atmosphere, a gas source or a vacuum. Examples of such optional further openings 50 are shown in FIG. Figure 2a . As shown in dotted lines on the right side of . As shown, the additional opening 50 can be a supply member or an extraction member, as indicated by the double-headed arrow. For example, if configured to supply, the additional opening 50 can be connected to a liquid supply or a gas supply, just like any of the supply members. Alternatively, if configured to extract, the additional opening 50 can be used to extract fluid, and can be connected to the atmosphere or a gas source or a vacuum, for example. For example, at least one additional opening 50 can be present between the air knife opening 26 and the gas recovery opening 28, and / or between the fixed opening 32 and the air knife opening 26.

[0057] Figure 2aThe two different versions of the fixed meniscus 33 of the left and right sides of the fluid handling structure 12. Due to the fixed position of the fixed opening 32, Figure 2a The version of the fluid handling structure 12 on the right side of may fix the meniscus 33 in a substantially fixed position relative to the final element 100 . Figure 2a A version of the fluid handling structure 12 on the left side of the apparatus may fix the meniscus 33 below the recovery opening 25, and the meniscus 33 may therefore be movable along the length and / or width of the recovery opening 25. In order for the radiation beam B to be directed to the full side of the substrate W under exposure, the substrate support WT supporting the substrate W is moved relative to the projection system PS. In order to maximize the output of the substrate W exposed by the lithographic apparatus, the substrate support WT (and the substrate W) are moved as fast as possible. However, there is a critical relative speed (commonly referred to as the critical scanning speed) above which the meniscus 33 between the fluid handling structure 12 and the substrate W becomes unstable. An unstable meniscus 33 carries a greater risk of loss of immersion liquid, for example in the form of one or more droplets. In addition, an unstable meniscus 33 carries a greater risk of causing bubbles to be contained in the immersion liquid, particularly when the confined immersion liquid passes through the edge of the substrate W.

[0058] Droplets present on the surface of the substrate W may apply a thermal load and may be a source of defects. Droplets may evaporate leaving behind dried stains, droplets may move and transport contaminants such as particles, droplets may collide with larger immersion liquids and introduce bubbles into larger objects, droplets may evaporate and apply a thermal load to the surface on which it is located. If the surface is associated with the positioning of a component of the lithographic apparatus relative to the substrate W being imaged, such thermal loads may be a cause of deformations and / or a source of positioning errors. Therefore, the formation of droplets on the surface is undesirable. In order to avoid the formation of such droplets, the speed of the substrate support WT is therefore limited to a critical scanning speed at which the meniscus 33 remains stable. This limits the throughput of the lithographic apparatus.

[0059] Figure 2a The left side of the fluid handling system in may include a spring 60. The spring 60 may be an adjustable passive spring configured to apply a biasing force to the fluid handling structure 12 in the direction of the substrate W. Thus, the spring 60 may be used to control the height of the fluid handling structure 12 above the substrate W. Such an adjustable passive spring is described in US 7,199,874, which is incorporated herein by reference in its entirety. Other biasing devices may also be suitable, for example, using electromagnetic force. Although the spring 60 is Figure 2a is shown on the left, but it is optional and does not need to be included. Figure 2a The spring 60 is not shown in any of the other figures, but may also include other features on the left side. Figure 2a , Figure 2b, Figure 2c or Figure 2d Other variations of the described fluid handling systems.

[0060] Figure 2b Two different versions of the fluid handling structure 12 are shown on its left and its right, which allow the meniscus 33 to move relative to the final element 100. The meniscus 33 can move in the direction of the moving substrate W. This reduces the relative speed between the meniscus 33 and the moving substrate W, which can improve stability and reduce the risk of the meniscus 33 breaking. The speed of the substrate W when the meniscus 33 breaks is increased to allow the substrate W to move faster under the projection system PS. Therefore, the throughput is improved.

[0061] Figure 2b As shown in Figure 2a Common features share the same reference numerals.The fluid handling structure 12 has an inner surface that is complementary to the conical surface of the frustoconical shape.The bottom surface of the fluid handling structure 12 is closer to the facing surface than the bottom flat surface of the frustoconical shape.

[0062] Immersion liquid is supplied to the immersion 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 frusto-conical bottom surface. The supply openings 34 are located around the inner surface, spaced around the path of the radiation beam B.

[0063] Immersion liquid is recovered from the immersion space 11 through a recovery opening 25 in the bottom surface of the fluid handling structure 12. When the facing surface moves below the fluid handling structure 12, the meniscus 33 can be transferred above 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. The immersion liquid can be recovered in 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.

[0064] An inner periphery 39 of the bottom surface of the fluid handling structure 12 extends away from the inner surface into the immersion space 11 to form a plate 40. The inner periphery 39 forms a small hole, the size of which can be set to match the shape and size of the radiation beam B. The plate 40 can be used to isolate immersion liquid at either side thereof. The supplied immersion liquid flows inwardly towards the hole, passes through the inner hole, and then flows radially outwardly under the plate 40 towards the surrounding recovery openings 25.

[0065] As in Figure 2bAs shown on the right side of , the fluid handling structure 12 can be divided into two parts: an inner part 12a and an outer part 12b. The inner part 12a and the outer part 12b can move relative to each other mainly in a plane parallel to the facing surface. The inner part 12a can have a supply opening 34, and the inner part 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 for recovering the immersion liquid flowing between the inner part 12a and the outer part 12b.

[0066] therefore, Figure 2b The two different versions of the fluid handling structure allow the meniscus 33 to move in the same direction as the substrate W, thereby achieving faster scanning speeds and increased throughput of the lithography apparatus. Figure 2b The transfer speed on the surface of the recovery opening 25 in the left side fluid handling structure 12 may be slow. Figure 2b The fluid handling structure 12 on the right side allows the meniscus 33 to move faster by moving the outer portion 12b relative to the inner portion 12a and the final element 100. However, it may be difficult to control the intermediate recovery member 42 to ensure that sufficient immersion liquid is provided between the inner portion 12a and the outer portion 12b to prevent contact therebetween.

[0067] Figure 2c On its left and its right are shown two different versions of the fluid handling structure 12 which may be used to secure the meniscus 33 of the immersion liquid to the fluid handling structure 12 as described above with respect to Figure 2a and / or Figure 2b described. Figure 2c As shown in Figure 2a and / or Figure 2b Common features share the same reference number.

[0068] The fluid handling structure 12 has an inner surface complementary to the conical surface of the truncated cone shape. The bottom surface of the fluid handling structure 12 is closer to the facing surface than the bottom flat surface of the truncated cone. The immersion liquid is supplied to the immersion space 11 through an opening formed in the surface of the fluid handling structure 12. The immersion liquid can be supplied through the supply opening 34 in the inner surface of the fluid structure 12. Alternatively or additionally, the immersion liquid can be supplied through the supply opening 20 in the inner surface of the fluid structure 12. Alternatively or additionally, the immersion liquid is supplied through the lower supply opening 23. The immersion liquid can be recovered via an extraction member, for example, via a recovery opening 21 formed in the inner surface and / or an overflow recovery member 24 and / or one or more openings in the surface of the fluid handling structure 12, as described below.

[0069] Figure 2cThe left and right sides of the two different versions of the fluid handling structure 12 have a fixed meniscus 33. Due to the fixed position of the recovery opening 32a, Figure 2c The version of the fluid handling structure 12 on the right side of may fix the meniscus 33 in a substantially fixed position relative to the final element 100 . Figure 2c The version of the fluid handling structure 12 on the left side of the embodiment may fix the meniscus 33 below the recovery opening 25 , and thus the meniscus 33 may move along the length and / or width of the recovery opening 25 .

[0070] As mentioned above about Figure 2b As described, the inner periphery of the bottom surface of the fluid handling structure 12 may extend away from the inner surface into the immersion space 11 to form a plate 40 as shown on the left. As described above, this may form a small hole and may isolate the immersion liquid at either side and / or cause the immersion liquid to flow inwardly toward the hole, through the inner hole, and then radially outwardly under the plate 40 toward the surrounding recovery openings 25. Although this feature is not Figure 2c , but is optional in combination with the other features shown. Preferably, as shown on the left side, immersion liquid is supplied to the immersion 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 truncated cone. The supply openings 34 are located around the inner surface, spaced around the path of the radiation beam B. Alternatively or additionally, the immersion liquid may be supplied through supply openings 20 in the inner surface of the fluid structure 12. Alternatively or additionally, the immersion liquid is supplied through the lower supply openings 23. Although the supply openings 34 are the preferred liquid supply, any combination of supply openings 34, supply openings 20 and / or lower supply openings 23 may be provided.

[0071] As in Figure 2c As shown on the left side of FIG. 1 , the fluid handling system may include a fluid handling structure 12 as described above and another device 3000. The fluid handling structure 12 may have an extraction member such as a recovery opening 25, and a liquid supply opening such as a lower supply opening 23. It should be understood that the fluid handling structure 12 may include the fluid handling structure 12 as described above. Figure 2a The left side of Figure 2a on the right side, Figure 2b The left side, and Figure 2b or (as described below) Figure 2c Any configuration disclosed on the right side, combined with another device 3000.

[0072] Another device 3000 may be referred to as a droplet catcher. Another device 3000 is provided to reduce the appearance of liquid on the surface of substrate W after the fluid handling structure 12 moves over the surface of substrate W. Another device 3000 may include a liquid supply member 3010 and at least one extraction member 3020. At least one extraction member 3020 may be formed in a shape that surrounds at least one supply member 3010 in a plan view. At least one liquid supply member 3010 may be configured to provide another liquid to a space 3110 between at least a portion of another device 3000 and the surface of substrate W. Another device 3000 may be configured to recover at least some of the liquid via at least one extraction member 3020. Another device 3000 may be used to combine any liquid left on the surface of substrate W with the liquid in space 3110, and then extract the liquid using another device 3000, thereby reducing the amount of liquid remaining on the surface of substrate W.

[0073] exist Figure 2c 3 , the further device 3000 is shown as a separate device from the fluid handling structure 12. The further device 3000 may be positioned adjacent to the fluid handling structure 12. Alternatively, the further device 3000 may be part of the fluid handling structure 12, i.e. integral with the fluid handling structure (as shown in FIG. 3 d , but any arrangement may be chosen).

[0074] Another device 3000 can be configured to provide liquid to a space 3110 that is separate from the liquid provided by the fluid handling structure 12.

[0075] Additionally or alternatively, the fluid handling structure 12 may have a Figure 2c . More specifically, the fluid handling structure 12 may include at least one liquid supply member, two extraction members (e.g., recovery openings 32a and 32b), and two gas supply members (e.g., gas supply openings 27a and 27b) formed on the surface of the fluid handling structure 12. The gas supply opening 27a may be omitted, i.e., is optional. The at least one liquid supply member may be the same as the lower supply opening 23 in the bottom surface of the fluid handling structure 12 described above, or may be the same as the lower supply opening 23 in the bottom surface of the fluid handling structure 12 described above. Figure 2b The supply opening 20 or the liquid supply opening 34 formed on the inner surface of the fluid handling structure 12 described on the left side of FIG. The liquid supply member, the extraction member and the gas supply member may be formed on the surface of the fluid handling structure 12. Specifically, these components may be formed on the surface of the fluid handling structure 12 facing the substrate W, that is, the bottom surface of the fluid handling structure 12.

[0076] At least one of the two extraction members may include a porous material 37 therein. The porous material 37 may be disposed within an opening (e.g., recovery opening 32a) through which the fluid handling structure 12 extracts fluid from below the fluid handling structure 12 and may recover immersion liquid in a single-phase flow. The other of the two extraction members, e.g., recovery opening 32b, may recover immersion fluid as a two-phase extractor. The porous material 37 need not be flush with the bottom surface of the fluid handling structure 12.

[0077] Specifically, the fluid handling structure 12 may include a liquid supply member (e.g., lower supply opening 23), having a first extraction member (e.g., recovery opening 32a) radially outward from the liquid supply member, and a first gas supply member (e.g., gas supply opening 27a) radially outward from the first extraction member, and a second gas supply member (e.g., gas supply opening 27b) radially outward from the second extraction member. Figure 2a Similarly, as described above (with respect to the fluid handling structure 12), there may be another opening in the bottom surface of the fluid handling structure 12, such as an opening to atmosphere, a gas source, or a vacuum.

[0078] For example, at least one further opening (not shown) may be provided in the bottom surface of the fluid handling structure 12. The further opening is optional. As described in the above arrangement, the further opening may be arranged between the first extraction member (e.g., recovery opening 32a) and the first gas supply member (e.g., gas supply opening 27a). Alternatively or additionally, as described in the above arrangement, the further opening may be arranged between the second extraction member (e.g., recovery opening 32b) and the second gas supply member (e.g., gas supply opening 27b). The further opening may be the same as the further opening 50 described above.

[0079] Optionally, the fluid handling structure 12 includes a recess 29. The recess 29 may be disposed between the recovery opening 32a and the recovery opening 32b, or between the gas supply opening 27a and the recovery opening 32b. The shape of the recess 29 may be uniform around the fluid handling structure 12, and may optionally include an inclined surface. In the case where the recess 29 is disposed between the recovery opening 32a and the recovery opening 32b, the gas supply opening 27b may be disposed on an inclined surface, such as Figure 2c As shown. In the case where the recess 29 is provided between the supply opening 27a and the recovery opening 32b, the gas supply opening 27b may be provided on a portion of the inclined surface or the bottom surface of the fluid handling structure 12 that is parallel to the surface of the substrate W. Alternatively, the shape of the recess 29 may vary around the circumference of the fluid handling structure 12. The shape of the recess 29 may vary to change the effect of the gas supplied from the gas supply member on the fluid below the fluid handling structure 12.

[0080] Figure 2d Two different versions of the fluid handling structure 12 are shown in the left and right halves thereof. Figure 2d The fluid handling structure 12 of the left half has a liquid injection buffer 41a and a liquid injection hole 41, the liquid injection buffer 41a holds a buffered amount of immersion liquid, and the liquid injection hole 41 supplies the immersion liquid from the liquid injection buffer to the space 11. The outer side of the liquid injection hole 41 is an inner liquid recovery hole 43 for guiding the liquid to the inner recovery buffer 43a provided with a porous member. A recess 29 is provided on the outer side of the inner liquid recovery hole 43, which is similar to the recess 29 described with respect to Figure 2c The recess described. On the outside of the recess 29, in the lower surface of the fluid handling structure 12 is a gas guide groove 44, to which an outer recovery hole 44a leads. The outer recovery hole 44a guides the two-phase recovery flow to an outer recovery buffer 44b also provided with a porous member. The outermost is a gas sealing hole 45, which communicates between the gas sealing buffer volume 45a and the space below the fluid handling structure 12 to provide a gas flow to contain the immersion liquid.

[0081] Figure 2d The fluid handling structure 12 in the right half has a liquid supply opening 20 on its inner inclined surface. On the lower side of the fluid handling structure 12 (from the inside to the outside), there is an extraction opening 25 provided with a porous member 37; a first gas knife opening 26a, a second gas knife opening 26b and a third gas knife opening 26c. Each of these openings leads to a groove in the lower side of the fluid handling structure 12, which provides a buffer volume. The outermost part of the fluid handling structure 12 is stepped to provide a larger spacing between the fluid handling structure 12 and the substrate W.

[0082] Figure 2a to Figure 2dThe example of different configurations that can be used as a part of a fluid treatment system is shown.It should be understood that the examples provided above refer to specific extraction components and recovery components, but it is not necessary to use the exact type of extraction components and / or recovery components.In some cases, different terms are used to indicate the position of the components, but the same functional characteristics can be provided.The examples of the extraction components mentioned above include recovery opening 21, overflow recovery device 24, recovery opening 25 (may include perforated plate and / or chamber 35), gas recovery opening 28, fixed opening 32, recovery opening 32a, recovery opening 32b and / or intermediate recovery device 42.The example of the supply component provided above includes supply opening 20, lower supply opening 23, air knife opening 26, gas supply opening 27a, gas supply port 27b and / or supply opening 34.Usually, the extraction component for extracting / recovering fluid, liquid or gas can be interchanged with any example in other examples used for extracting / recovering fluid, liquid or natural gas respectively.Similarly, the supply component for supplying fluid, liquid or gas can be interchanged with any example in other examples used for supplying fluid, liquid or gas respectively. The extraction member may extract / recover fluid, liquid or gas from the space by connecting to a negative pressure that draws the fluid, liquid or gas into the extraction member. The supply member may supply fluid, liquid or gas to the space by connecting to an associated supply device.

[0083] As previously mentioned, while the use of immersion fluids / liquids is advantageous for improving the resolution of smaller features on a substrate, the use of immersion fluids or liquids also presents problems associated with defects introduced into the substrate.

[0084] Typically, when an immersion liquid is used, droplets of the immersion liquid may remain on the surface of the substrate W. The meniscus 33 at the edge of the immersion liquid may collide with any droplets on the surface of the substrate W. When droplets hit the meniscus 33, gas may become trapped in the immersion liquid. This results in bubbles in the immersion liquid. The formation of bubbles in the immersion liquid may lead to defects on the substrate W. Droplets remaining on the surface of the substrate W may cause dry spots and / or affect the chemical properties of the resist, also leading to defects.

[0085] It is well known that the incidence of droplets increases with the speed of movement of the substrate W relative to the fluid handling system. In some cases, there is no or negligible droplet formation below the critical scanning speed, while there is significant droplet formation above the critical scanning speed. The critical scanning speed is related to the static receding contact angle between the immersion liquid and the resist disposed on the substrate W. Increasing the static receding contact angle increases the critical scanning speed. Since the critical scanning speed may be a limiting factor in the throughput of the lithographic apparatus, it is desirable to increase the critical scanning speed. Efforts to increase the critical scanning speed include increasing the static receding contact angle by changing the formulation of the resist or by providing a top coating over the resist.

[0086] A technique for increasing the critical scan speed is disclosed in a document referred to herein as RD681087. The entire contents of RD681087 are incorporated herein by reference. RD681087 is a publication of QUESTEL RESEARCH DISCLOSURE. RD681087 is a document entitled A FLUID HANDLING SYSTEM, METHOD AND LITHGRAPHIC APPARATUS, with a database number of 681087 and a digital publication date of December 21, 2020. The link to RD681087 is: https: / / www.researchdisclosure.com / database / RD681087 (Viewed on 26 June 2022)

[0087] RD681087 discloses increasing the maximum permissible speed of relative motion between a fluid handling system and a substrate without significant droplet formation by providing a fluid handling system in which a meniscus of a fluid moves in response to relative motion of the substrate and the fluid handling system. Figure 3a and Figure 3b Some of the techniques disclosed in RD681087 are described.

[0088] Figure 3a and Figure 3b A portion of a fluid handling system 301 is shown. The fluid handling system 301 may confine an immersion liquid in a liquid confinement space between a portion of the projection system PS and the surface of the substrate W. The immersion liquid may be any of the immersion fluids described above. For example, the immersion liquid may be water. A radiation beam B projected from the projection system PS may irradiate the surface of the substrate W through the immersion liquid.

[0089] Figure 3a Only a portion of the fluid handling system 301 is shown supporting a meniscus 310 of immersion liquid. The meniscus 310 forms a boundary between the immersion liquid and the surroundings of the fluid handling system 301. Although Figure 3a 306, but the main part of the fluid handling system 301 is positioned in the direction shown by arrow 306. The main part of the fluid handling system 301 may include immersion liquid, and may include the above reference Figure 2a to Figure 2d Any part of the various structures disclosed, or the main part of the fluid handling system is indeed any other system that positions the immersion liquid below the projection system PS. In particular, the main part of the fluid handling system 301 may include an immersion space, such as the one described in reference Figure 2a to Figure 2d An immersion space 11 is described.

[0090] like Figure 3aAs shown, a fluid handling system 301 is arranged above a substrate W. The substrate W may include a wafer 305 and a resist coating 304 on the wafer 305. A channel 308 exists between the fluid handling system 301 and the substrate W. A portion of the channel 308 between the main portion 301 of the fluid handling system positioned in direction 306 and the meniscus 310 may include immersion liquid. A portion of the channel 308 between the meniscus 310 and the external environment of the fluid handling system 301 positioned in direction 307 may include a gas.

[0091] The fluid handling system 301 comprises a first extraction member 302. The first extraction member 302 comprises a first extraction conduit 302b. The first extraction conduit 302b is a fluid conduit and may provide a flow of immersion liquid out of the fluid handling system 301. The first extraction member 302 also comprises a first extraction opening 302a arranged in an upper surface of the channel 308. The first extraction opening 302a is an end of the first extraction conduit 302b.

[0092] The fluid handling system 301 comprises a second extraction member 303. The second extraction member 303 comprises a second extraction conduit 303b. The second extraction conduit 303b is a conduit for a fluid such as a gas. The second extraction member 303 also comprises a second extraction opening 303a arranged in the upper surface of the channel 308. The second extraction opening 303a is the end of the second extraction conduit 303b.

[0093] There is an upper surface of the channel 308 between the first and second extraction members 302, 303, which is referred to herein as a dampener 311. The length of the dampener 311 defines the spacing of the first and second extraction members 302, 303 along the length of the channel 308.

[0094] The first extraction member 302 may be configured to extract immersion liquid via a fluid flow 309. The only fluid flow through the first extraction member 302 may be substantially the fluid flow 309 of the immersion liquid. However, the first extraction member 302 may also extract some gas from the external environment of the fluid treatment system 301. Thus, the fluid flow through the first extraction member 302 may be a two-phase flow. When there is a fluid flow through the first extraction member 302, there may be a gas flow 314 through the second extraction member 303 at the same time.

[0095] The second extraction member 303 may be configured to extract gas from the channel 308 . Figure 3b A gas flow 314 of the gas extraction is shown. The gas flow 314 may create a negative pressure in the channel 308.

[0096] although Figure 3a and Figure 3b306, but the main part of the fluid handling system 301 positioned in direction 306 may include a fluid handling structure having an inner surface that is configured to confine immersion liquid. The first extraction member 302 and the second extraction member 303 are positioned radially away from the main part of the fluid handling system 301. The second extraction member 303 may be positioned further away from the inner surface of the fluid handling structure than the first extraction member 302. Alternatively, the first extraction member 302 and the second extraction member 303 may be part of the main part of the fluid handling system 301. The second extraction member 303 may be positioned further away from the midpoint of the fluid handling system 301 than the first extraction member 302.

[0097] The first operating state of the fluid treatment system 301 is as follows Figure 3a As shown. In the first operating state, there may be no relative motion between the substrate W and the fluid handling system 301. The first extraction member 302 may be configured such that when in the first operating state, the amount of immersion liquid extracted through it does not substantially exceed the amount required to maintain the meniscus 310 at substantially the same position along the channel 308. When there is no relative motion between the substrate W and the fluid handling system 301, the fluid flow rate through the first extraction member 302 is substantially the minimum flow rate capable of keeping the meniscus 310 stationary.

[0098] The second operating state of the fluid handling system is as follows Figure 3b In the second operating state, the substrate W may be moved relative to the fluid handling system 301. The second operating state comprises a scanning motion in a scanning direction. The scanning direction may be substantially perpendicular to the propagation direction of the radiation beam B. The scanning direction may be as follows: Figure 3b The second operating state may include other relative movements between the substrate W and the fluid handling system 301 besides the scanning movement. For example, the second operating state may include a preparation movement before the scanning movement.

[0099] The first extraction member 302 may be configured such that the amount of immersion liquid extracted by it is substantially the same in the first operating state and the second operating state. The movement of the substrate W in the direction 312 generates a shear force on the immersion liquid in the channel 308. As a result, the meniscus 310 moves in the direction 313 along the channel 308. The increased flow of immersion liquid into the channel 308 may be referred to as Couette flow, and may also be referred to as shear-driven flow or pressure-driven flow. The negative pressure generated in the channel 308 by the gas flow 314 also supports the movement of the meniscus 310 along the channel 308.

[0100] In the second operating state, the fluid flow through the first extraction member 302 does not keep the meniscus 310 stationary. When there is no relative motion between the fluid handling system 301 and the substrate W, the fluid flow through the first extraction member 302 is only sufficient to maintain the meniscus 310 stationary. Therefore, in the second operating state, the meniscus 310 moves along the channel 308.

[0101] Advantageously, the maximum permissible speed of relative motion between the fluid handling system 301 and the substrate W is increased. The speed of relative motion between the meniscus 310 and the substrate W may be less than or equal to a critical scan speed, so that significant droplet formation does not occur. The speed of relative motion between the fluid handling system 301 and the meniscus 310 increases the speed of relative motion between the fluid handling system 301 and the substrate W. The speed of relative motion between the fluid handling system 301 and the substrate W may be up to twice the critical scan rate of known systems where the meniscus 310 is substantially stationary within the channel 308.

[0102] The damper 311 may be configured such that its surface properties support proper movement along it of the end of the meniscus 310. In particular, the surface of the damper 311 may be coated or otherwise configured to be any of hydrophobic, hydrophilic, or porous.

[0103] The surface of the damper 311 may be configured such that it is substantially parallel to the surface of the substrate W.

[0104] Alternatively, the surface of the damper 311 may be curved or inclined away from the surface of the substrate W. That is, a first end of the surface of the damper 311 is located at the first extraction member 302, and a second end of the surface of the damper 311 is located at the second extraction member 303. The surface of the damper 311 may be configured such that a spacing between the surface of the damper 311 and the surface of the substrate W is larger at the second end than at the first end.

[0105] The damper 311 may be referred to as the first damper 311. Figure 3a and Figure 3b As shown, the fluid handling system 301 may include a second damper 315. The surface of the second damper 315 is the length of the first damper 311 from the upper surface of the channel 308 on the other side of the first extraction member 302. The second damper 315 may be configured so that the immersion liquid is supported between the surface of the second damper 315 and the surface of the substrate W.

[0106] The surface of the second damper 315 may be parallel to the surface of the substrate W. The interval between the surface of the second damper 315 and the surface of the substrate W may be the same as the interval between the entire or at least a portion of the surface of the first damper 311 and the surface of the substrate W. Alternatively or additionally, the distance between the first damper 311 and the surface of the substrate W may be greater than the interval between at least a portion of the surface of the second damper 315 and the surface of the substrate W.

[0107] An upper surface 316 of the channel 308 starting at the second extraction member 303 and extending in the direction 307 to the external environment of the fluid handling system 301 can be parallel to the surface of the substrate W. Alternatively, the upper surface 316 of the channel 308 can be inclined / curved so that the spacing between the lower surface 316 of the channel 308 and the surface of the substrate W changes. The pressure of the gas in the channel 308 can depend on the shape of the upper surface 316. The shape of the surface 316 can be determined so as to generate an appropriate gas pressure in the channel 308 for supporting the movement of the meniscus 310 under the expected operating conditions.

[0108] It has been found that the above technology works well during the exposure process that usually only includes relatively small meandering motion. However, when long-distance high-speed motion is required, problems arise. Long motion can include motion to avoid sensors and motion during substrate support changes. Long motion can be over a distance of up to about 30 cm. When high-speed motion is performed over a long distance, the distance that the curved liquid surface 310 moves along the channel 308 increases. Therefore, the minimum length required for the surface of the damper 311 between the first extraction member 302 and the second extraction member 303 increases. During exposure only, the required minimum length of the damper 311 can be about 2 cm to 5 cm. However, for possible long high-speed motions, the required minimum length of the damper 311 can be increased to about 10 cm to 20 cm. This increase in the damper length greatly increases the occupied space of the fluid handling system 301, and also increases the risk of water loss outside the wetting area on the substrate W.

[0109] Embodiments solve the above problems by providing a meniscus control surface that allows two different operating states. In a first operating state, liquid is extracted through the meniscus control surface so that the meniscus remains stationary within the channel 308, i.e., the meniscus 310 is fixed to the meniscus control surface. In a second operating state, substantially no liquid is extracted through the meniscus control surface so that the meniscus 310 is able to move along the channel 308, as described above with reference to Figure 3a and Figure 3b described.

[0110] The first operating state is used when high speed motion over long distances is required, so no long damper is required. In the first operating state, the speed of relative motion between the substrate W and the fluid handling system 301 can be limited to a speed below the speed at which a large amount of droplet formation occurs on the substrate W. The second operating state is used when high speed motion over short distances is required. In the second operating state, the speed of relative motion between the substrate W and the fluid handling system 301 can be faster than in the first operating state due to the motion of the meniscus 310. Figure 4 and Figure 5 The embodiments are described in more detail.

[0111] Figure 4 A portion of a fluid treatment system 301 according to a first embodiment is schematically shown. In the first embodiment, the portion of the fluid treatment system 301 may be similar to that described above with reference to Figure 3a and Figure 3b The described portion is different in that this portion of the fluid handling system further comprises a meniscus control surface 401. The meniscus control surface 401 is constituted by the upper surface of the channel 308, ie the meniscus control surface is located on the side of the channel 308 opposite to the substrate W.

[0112] The meniscus control surface 401 may be located proximate to the damper 311 and between the first extraction member 302 and the second extraction member 303. The meniscus control surface 401 is preferably located proximate to the first extraction member 302.

[0113] It should be noted that Figure 4 A meniscus control surface 401 is schematically shown, and Figure 4 Not drawn to scale. Meniscus control surface 401 is preferably much shorter than damper 311. For example, the length of meniscus control surface 401 may be between about 1 mm and 10 mm, preferably less than 5 mm. The length of damper 311 may be about 20 mm to 50 mm or longer.

[0114] The meniscus control surface 401 may be made of any of a variety of materials known in the art. For example, the meniscus control surface 401 may be made of metal or plastic. Preferably, the meniscus control surface 401 is coated so that its surface properties depend on the coating. In particular, a coating may be applied that makes the meniscus control surface 401 hydrophilic. Preferably, the damper 311 is configured so that its surface is hydrophobic. Such surface properties of the meniscus control surface 401 and the damper 311 support different first and second operating states, as described in detail later.

[0115] The meniscus control surface 401 may be the surface of a microsieve. The microsieve includes small openings that are arranged so that a fluid (such as an immersion liquid) can flow through them. On the side of the microsieve opposite to the channel 308, there may be a bypass flow path. The bypass flow path may be arranged to provide a liquid flow along the side of the meniscus control surface 401 opposite to the substrate W. The bypass flow path may include a liquid inlet 402 that is configured to supply a liquid flow 403 to the bypass flow path. The bypass flow path may also include a liquid outlet 405 that is configured to provide a liquid flow 404 that flows out of the bypass flow path.

[0116] The bypass flow path can be arranged to wet the openings of the microsieve. That is, even when there is substantially no liquid flow through the openings, the liquid flow along the bypass flow path can ensure that the openings of the microsieve are substantially completely covered by liquid. Therefore, the microsieve can have a wetted surface in all operating states of the fluid treatment system 301. The microsieve is preferably configured so that the liquid in its openings has a high capillary pressure.

[0117] although Figure 4 Although not shown, the first embodiment may also include a flow control system configured to control the flow of liquid through the liquid outlet 405. The flow control system may include, for example, a variable displacement pump, a multi-way valve system that can apply different flow restrictions, or any other technology for controlling the flow of liquid through the liquid outlet 405.

[0118] The liquid received by the liquid inlet 402 may be branched from the same liquid supply as the main portion of the fluid handling system 301. Alternatively, a separate liquid supply may be provided for the bypass flow path.

[0119] The flow control system may be configured to control a portion of the fluid treatment system 301 in accordance with the first embodiment to be in at least one of a first operating state and a second operating state.

[0120] In the first operating state, the flow control system can be configured to apply negative pressure above the microsieve. The flow control system can be configured so that the flow of the liquid flow 404 flowing out of the liquid outlet 405 is greater than the flow of the supply liquid flow 403 through the liquid inlet 402. The additional liquid in the liquid flow 404 flowing out of the bypass flow path is provided by the immersion liquid flow through the microsieve opening. The effect of the liquid flow through the microsieve is that the curved liquid surface 310 is fixed to the surface of the microsieve. In other words, the curved liquid surface 310 of the immersion liquid remains substantially stationary between the surface of the microsieve and the surface of the substrate W. The flow control system is preferably configured so that, in the first operating state, the negative pressure applied above the microsieve is less than the capillary pressure of the microsieve opening. This ensures that all openings of the microsieve remain wetted in the first operating state.

[0121] The micro-sieve is preferably positioned proximate to the first extraction member 302 so as to reduce the overall wetted area when in the first operating state.

[0122] In the second operating state, the flow control system can be configured so that the flow control system applies a negative fluid pressure to the microsieve opening, which is less than, preferably significantly less than, the capillary pressure of the opening. The pressure difference at both ends of the microsieve is preferably minimal and can be substantially zero. The flow rate of the liquid through the liquid outlet 405 can be substantially the same as the flow rate of the liquid through the liquid inlet 402. There can be substantially no flow of immersion liquid or gas through the microsieve opening. If there is a small amount of liquid flow from the channel 308 through the opening of the microsieve covering the liquid in the channel 308, this can be compensated by reducing the liquid extraction through the first extraction member 302.

[0123] In the second operating state, the meniscus 310 is free to move relative to the surface of the microsieve and the surface of the damper 311. Thus, the fluid handling system 301 may operate with a movable meniscus, substantially as described in RD681087.

[0124] In the second operating state, the flow control system may alternatively be configured to apply a slight overpressure above the microsieve, so that a small amount of liquid flows from the bypass flow path through the microsieve into the channel 308. This may increase the permissible movement speed of the substrate W relative to the fluid handling system 301 in the second operating state.

[0125] In the first operating state, the flow rate of the liquid flow 404 flowing out of the bypass flow path may be a first fluid flow rate. In the second operating state, the flow rate of the liquid flow 404 flowing out of the bypass flow path may be a second fluid flow rate. The first fluid flow rate may be greater than the second fluid flow rate.

[0126] In the first embodiment, Figure 4 The portion of the fluid handling system 301 shown in FIG. 3 may be connected to Figure 3a and Figure 3b The parts of the fluid handling system 301 shown in and described in RD681087 are substantially the same.

[0127] Advantageously, the arrangement of the meniscus control surface 401 allows for proper control of the meniscus 310 when long movements are required. An advantage of wetting the meniscus control surface 401 in all operating states is that in all operating states substantially only liquid flows through the meniscus control surface 401. This single-phase flow does not exert large forces on the substrate W. Different operating states can also be switched quickly.

[0128] If the fixing of the meniscus 310 is alternatively performed at the first extraction member 302, it is impossible to avoid that both liquid and gas flow through the first extraction member 302. Such a two-phase flow will increase the extraction force required through the first extraction member 302 and exert a large force on the substrate W. In addition, the time required to switch from the second operating state to the first operating state may exceed 100 ms, which may be much slower than the switching time when using the technology according to the embodiment.

[0129] Figure 5 A portion of a fluid handling system 301 according to a second embodiment is schematically shown. The second embodiment may differ from the first embodiment and the technique disclosed in RD681087 in that the second embodiment does not have a first extraction member 302. In the second embodiment, the meniscus control surface 401 additionally provides fluid extraction, which is performed by the first extraction member 302 in the first embodiment and the technique disclosed in RD681087.

[0130] In the second embodiment, fluid flow through the microsieve can be increased by substantially the same amount as fluid flow through the first extraction member 302 in the first embodiment. As fluid flow through the microsieve is increased, fluid extraction through the liquid outlet 405, i.e., liquid flow 404 out of the bypass flow path, can be similarly increased.

[0131] In the first operating state and the second operating state, the fluid flow rate may be appropriately changed without the first extraction member 302. The operation of the second embodiment may be otherwise the same as the first embodiment.

[0132] Advantageously, in the second embodiment there is no first extraction member 302. This reduces the space occupied by the extraction member and also reduces the cost.

[0133] As previously described, the rate of occurrence of droplets and / or bubbles increases with the speed of movement of the substrate W relative to the fluid handling system. Below a critical scan speed, there may be no or negligible formation of droplets and / or bubbles, while above the critical scan speed, there may be significant formation of droplets and / or bubbles. The critical scan speed is related to the static receding contact angle between the immersion liquid and the resist disposed on the substrate W. Therefore, the critical scan speed may be increased by appropriately controlling the contact angle.

[0134] According to a third embodiment, a new technique is provided for increasing the maximum permissible speed of relative motion between a fluid handling system and a substrate W. The electrowetting effect is used to change the contact angle and thus increase the critical scan speed. The electrowetting effect can additionally or alternatively be used to increase the critical scan speed by changing the contact line of the immersion fluid. The contact line is the boundary line of the meniscus of the immersion fluid on the substrate-facing surface of the fluid handling structure.

[0135] Figure 6a and Figure 6b A portion of a fluid handling system 601 according to a third embodiment is schematically shown. The fluid handling system 601 comprises an electrowetting structure 605. At least a portion of the substrate-facing surface of the fluid handling system 601 is provided by the substrate-facing surface of the electrowetting structure 605. Between the substrate-facing surface of the electrowetting structure 605 and the substrate W there is a meniscus 602 of an immersion fluid.

[0136] like Figure 6a As shown, when the fluid handling system 601 is stationary and the substrate W moves in direction 603, the meniscus 602 can move in direction 604 along the surface of the electrowetting structure 605 facing the substrate. Figure 6b As shown, when the fluid handling system 601 is stationary and the substrate W moves in the direction 606, the meniscus 602 can move in the direction 607 along the substrate-facing surface of the electrowetting structure 605. The movement of the meniscus 602 along the surface of the electrowetting structure 605 is similar to the movement of the meniscus 310 along the surface of the damper 311 in the first and second embodiments described above. Therefore, the movement of the meniscus 602 increases the maximum allowable speed of the relative movement between the fluid handling system 601 and the substrate W.

[0137] The electrowetting structure 605 is configured to use the electrowetting effect to change the contact angle and / or contact line of the meniscus 602. The electrowetting effect is a known technique in which an electric field is used to change the properties of a surface for a fluid, see https: / / en.wikipedia.org / wiki / Electrowetting (Viewed on 25 May 2023)

[0138] The electrowetting structure 605 includes one or more embedded electrodes. Each electrode can be covered by an electrical insulator (not shown) at least on its side facing the substrate. The electrical insulator can be a dielectric. The surface of the electrical insulator facing the substrate can be coated to make it hydrophobic. The surface of the electrical insulator facing the substrate can be the surface along which the curved liquid surface 602 can move. A voltage relative to the ground potential can be applied to each electrode to generate an electric field. The ground potential can be set in the fluid handling system 601, the substrate support WT, the substrate W or another part of the lithographic apparatus. Due to the electrowetting effect, the electric field depending on the applied voltage can change the characteristics of the surface facing the substrate of the electrowetting structure 605. The contact angle and / or contact line of the curved liquid surface 602 can therefore change in response to the applied voltage.

[0139] According to the following formula, the contact angle θ EW Depends on the voltage applied to the electrodes:

[0140]

[0141] in:

[0142] -θ EW is the contact angle;

[0143] -γ SV is the surface free energy of the interface between the substrate-facing surface of the electrowetting structure 605 and the gas in the surrounding environment (which may be air);

[0144] -γ S L is the surface free energy of the interface between the substrate-facing surface of the electrowetting structure 605 and the immersion fluid (which may be water);

[0145] -γ LV is the surface free energy of the interface between the immersion fluid and the gas in the surrounding environment;

[0146] - C is the capacitance per unit area; and

[0147] -V is the applied voltage.

[0148] The electrowetting structure 605 may be used to change the contact angle and thereby reduce the contact line movement speed at the substrate end of the meniscus 602 .

[0149] like Figure 6a As shown, the fluid handling system 601 can be stationary and the substrate W is moved in direction 603. By applying a voltage to one or more electrodes in the electrowetting structure 605, the contact angle at the fluid handling system end of the meniscus 602 is reduced. This also causes the contact line to move in direction 604, and thereby partially reduces the contact line motion at the substrate end of the meniscus 602. This allows for faster relative motion of the fluid handling system 601 and the substrate W.

[0150] like Figure 6b As shown, the fluid handling system 601 can be stationary and the substrate W is moved in direction 606. Alternatively, the electrowetting structure 605 can be operated so that no voltage or a voltage of reduced magnitude is applied to one or more electrodes of the electrowetting structure. The hydrophobic properties of the substrate-facing surface of the electrowetting structure 605 can increase the movement of the contact line in direction 607. This partially reduces the contact line movement at the substrate end of the meniscus 602. This has the effect of changing the contact angle and thereby allowing faster relative movement of the fluid handling system 601 and the substrate W.

[0151] In the third embodiment, one or more electrodes of the electrowetting structure 605 are controllable to change the contact angle and / or contact line of the meniscus 602 of the immersion fluid. Thus, the third embodiment allows for faster relative movement of the fluid handling system 601 and the substrate W without significantly increasing the formation of droplets and / or bubbles.

[0152] The implementation of the third embodiment includes an electrowetting structure 605 used in combination with the techniques of the first and second embodiments described above. In particular, as previously described with reference to Figures 3a to 5 As described, the damper 311 may include an electrowetting structure 605 . Movement of the meniscus 310 along a surface of at least a portion of the damper 311 may depend on control of the electrowetting structure 605 .

[0153] According to a fourth embodiment, the electrowetting structure 605 comprises a plurality of electrodes (not shown) arranged in an array. The electrodes can be controlled independently of each other. The properties of different regions of the surface facing the substrate of the electrowetting structure 605 can be varied by the operation of the electrodes. This can allow advantageous control of the contact line and / or contact angle of the immersion fluid, as well as the movement of any droplets of the immersion fluid on the surface of the electrowetting structure 605.

[0154] In a first implementation of the fourth embodiment, the electrowetting structure 605 may be used to pre-wet at least a portion of a surface of the electrowetting structure 605. Using known techniques, the meniscus 602 wets a portion of a surface of the fluid handling system 601 in response to movement of the substrate W. The pre-wetting technique of the fourth embodiment moves the immersion fluid over at least a portion of the surface of the fluid handling system 601 prior to wetting caused by movement of the substrate W. The pre-wetted surface is at least a portion of the surface of the electrowetting structure 605 that faces the substrate. The pre-wetted surface may be referred to as a precursor film of the immersion fluid.

[0155] The electrodes within the electrowetting structure 605 may be controlled so that some of the immersion fluid pre-wets at least some of the surfaces of the electrowetting structure. The effect of the pre-wetting is that the contact line advances before the substrate W moves. As a result, the contact line travels a smaller distance in response to the movement of the substrate W.

[0156] Pre-wetting may be performed for all movements of the substrate W. In particular, pre-wetting may be performed for a scanning movement and a positioning movement between the scanning movements.

[0157] In a second implementation of the fourth embodiment, the electrodes of the electrowetting structure 605 may be operated to slow down the movement of the meniscus 602 as it passes the edge of the substrate W.

[0158] In a third implementation of the fourth embodiment, the electrowetting structure 605 may be used to move any droplets of immersion fluid on the surface of the electrowetting structure 605. The droplets may be moved to a position where they can be extracted.

[0159] In a fourth implementation of the fourth embodiment, the electrowetting structure 605 can be used in combination with the techniques of the first and second embodiments described previously. Figures 3a to 5 As described, the damper 311 may include an electrowetting structure 605 . Movement of the meniscus 310 along a surface of at least a portion of the damper 311 may depend on control of the electrowetting structure 605 .

[0160] Embodiments include many modifications and variations of the above-described techniques.

[0161] In the third and fourth embodiments described above, Figure 6a and Figure 6b The illustrated exemplary implementation includes a liquid-filled conduit proximate the inner end of the electrowetting structure 605. The liquid-filled conduit is optional and may not be present in all implementations of the third and fourth embodiments.

[0162] In the first and second embodiments described above, the meniscus control surface 401 is a micro-sieve. Embodiments also include a meniscus control surface 401 that is any other type of surface over which a liquid can flow. For example, the meniscus control surface 401 may be a porous member, include micro-slits, or include capillaries.

[0163] In the above-described embodiment, a first extraction member 302 and a second extraction member 303 are described. Embodiments include the presence of a plurality of such first extraction members 302 and / or a plurality of such second extraction members 303. A plurality of first extraction members 302 may be arranged around the midpoint of the fluid handling system 301. A plurality of first extraction members 302 may be arranged in any configuration. For example, they may be circular, square, rectangular, or star-shaped. The first extraction opening 302a of each first extraction member 302 may have any shape. For example, each first extraction opening 302a may be circular, square, rectangular, or slot-shaped. A plurality of second extraction members 303 may be arranged around the midpoint of the fluid handling system 301. For example, they may be circular, square, rectangular, or star-shaped. The configuration of the second extraction member 303 may be the same as or different from the configuration of the first extraction member 302.

[0164] The determination of whether to use the first operating state or the second operating state, and the speed of relative movement between the fluid handling system 301 and the substrate W in each operating state, may depend on a variety of different circumstances. These may include the desired length of movement, the type of process being performed, and the surface characteristics of the substrate W or substrate support. For example, the use of the first operating state and the speed of movement may depend on the hydrophobicity of the surface of the substrate W.

[0165] In the above-described embodiments, the bypass flow path substantially only includes liquid flow. Embodiments also include bypass flow paths that provide fluid flow, wherein the fluid is a bubbly flow. That is, the fluid flow in the bypass flow path may include both liquid flow and gas flow.

[0166] In a first operating state, an embodiment includes a flow control system configured such that in addition to the immersion liquid flow through the openings of the microsieve, there is also a small amount of gas flow through the microsieve. This may allow a greater force to be applied to keep the meniscus 310 stationary relative to the surface of the microsieve.

[0167] The addition of the meniscus control surface 401 according to the embodiments may be applied to all techniques disclosed in RD681087, as well as other types of fluid handling systems.

[0168] In the above embodiments, the meniscus control surface 401 and the surface of the damper 311 are described as being located at the upper surface of the channel 308. In a typical configuration with a horizontally arranged substrate W, this surface would be the upper surface of the channel 308. However, more generally, embodiments include the meniscus control surface 401 and the surface of the damper 311 arranged in the surface of the fluid handling system 301, the surface of the damper being substantially parallel to the surface of the substrate W. The surface of the substrate W is not limited to a horizontal arrangement.

[0169] The present invention may provide a lithographic apparatus. The lithographic apparatus may have any / all other features or components of the lithographic apparatus described above. For example, the lithographic apparatus may optionally include at least one or more of the following: a source SO, an illumination system IL, a projection system PS, a substrate support WT, etc.

[0170] In particular, the lithographic apparatus may include a projection system PS configured to project a radiation beam B towards a surface area of ​​a substrate W. The lithographic apparatus may further include a fluid handling system 301 as described in any of the above embodiments and variations.

[0171] The lithographic apparatus may include an actuator configured to move the substrate W relative to the fluid handling system 301. Thus, the actuator may be used to control the position of the substrate W (or alternatively, the position of the fluid handling system 301). The actuator may be or may include a substrate support (e.g., substrate table) WT and / or a substrate holder configured to hold the substrate W and / or a second positioner PW configured to accurately position the substrate support WT.

[0172] Although the use of lithography apparatus in IC manufacturing may be specifically mentioned herein, it should be understood that the lithography apparatus described herein may have other applications. Other possible applications include the manufacture of integrated optical systems, guidance and detection modes of magnetic domain memory, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads, etc.

[0173] Where the context permits, embodiments of the present invention may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the present invention may also be implemented by instructions stored on a machine-readable medium, which may be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium may include a read-only memory (ROM); a random access memory (RAM); a magnetic storage medium; an optical storage medium; a flash memory device; an electrical, optical, acoustic, or other form of propagation signal (e.g., a carrier wave, an infrared signal, a digital signal, etc.), etc. In addition, firmware, software, routines, instructions may be described herein as performing certain actions. However, it should be understood that such descriptions are merely for convenience, and that such actions are actually caused by a computing device, processor, controller, or other device that executes the firmware, software, routines, instructions, etc., and that doing so may cause an actuator or other device to interact with the physical world.

[0174] Although embodiments of the invention may be specifically referred to herein in the context of a lithographic apparatus, embodiments of the invention may also be used in other apparatuses. Embodiments of the invention may form part of a mask inspection apparatus, a metrology apparatus, or any apparatus that measures or processes an object, such as a wafer (or other substrate) or a mask (or other patterned device). These apparatuses may generally be referred to as lithographic tools. Such lithographic tools may use ambient (non-vacuum) conditions.

[0175] Although specific reference has been made above to embodiments of the invention being used in the context of optical lithography, it will be appreciated that the invention is not limited to optical lithography where the context permits.

[0176] The examples include the following numbered clauses:

[0177] 1. A fluid handling system for a lithographic apparatus, wherein the fluid handling system is configured to confine an immersion fluid in a liquid confinement space between a portion of a projection system in the lithographic apparatus and a surface of a substrate, whereby a radiation beam projected from the projection system can illuminate the surface of the substrate by passing through the immersion fluid, the fluid handling system comprising a meniscus control surface for controlling movement of a meniscus of the immersion fluid;

[0178] wherein, in a first operational state, the meniscus control surface is configured to maintain a meniscus of the immersion fluid substantially stationary between the meniscus control surface and the surface of the substrate; and

[0179] Wherein, in a second operational state, the meniscus control surface is configured to allow said movement of the meniscus of the immersion fluid.

[0180] 2. The system according to clause 1 further comprising a damper;

[0181] Wherein, in the second operating state, the damper is configured to support the movement of the meniscus of the immersion fluid between a surface of the damper and the surface of the substrate.

[0182] 3. A system according to clause 1 or 2, wherein the meniscus control surface comprises a surface of a micro-sieve or a porous member.

[0183] 4. A system according to any of the preceding clauses, wherein the meniscus control surface comprises a wetting surface.

[0184] 5. The system of any of the preceding clauses, further comprising a bypass flow path configured to provide a fluid flow to the substrate along an opposite side of the meniscus control surface.

[0185] 6. The system according to clause 5, further comprising: a fluid inlet configured to supply a fluid flow to the bypass flow path; and

[0186] The fluid outlet is configured to provide the fluid flow out of the bypass flow path.

[0187] 7. The system of clause 6, further comprising a flow control system configured to control the flow of fluid through the fluid outlet.

[0188] 8. The system according to clause 7, wherein the flow control system is configured to control the fluid flow through the fluid outlet to a first fluid flow rate or a second fluid flow rate;

[0189] The first fluid flow rate is greater than the second fluid flow rate;

[0190] The first fluid flow rate is used to provide the first operating state; and

[0191] The second fluid flow rate is used to provide the second operating state.

[0192] 9. The system according to any of clauses 5 to 8, wherein the fluid flow in the bypass flow path is a liquid flow.

[0193] 10. A system according to any of the preceding clauses, wherein the meniscus control surface is hydrophilic.

[0194] 11. A system according to any of the preceding clauses, wherein the damper surface is hydrophobic, and / or wherein the damper is provided with an electrowetting structure, the electrowetting structure comprising one or more electrodes, the one or more electrodes being arranged to apply an electrowetting effect to at least a portion of a surface facing a substrate of the fluid handling system; and the one or more electrodes of the electrowetting structure are controllable so as to change the contact angle and / or contact line of the curved liquid surface of the immersion fluid.

[0195] 12. A system according to any of the preceding clauses, wherein:

[0196] The system comprises a fluid handling structure having an inner surface configured to confine the immersion fluid;

[0197] The system further comprises an extraction member configured to extract the immersion fluid;

[0198] The meniscus control surface and the extraction member are positioned radially away from the inner surface of the fluid handling structure; and

[0199] The extraction member is positioned further away from the inner surface of the fluid handling structure than the meniscus control surface.

[0200] 13. A system according to clause 12, wherein the extraction member is configured such that, in use, substantially only gas flows through the extraction member.

[0201] 14. A system according to any of clauses 12 or 13, comprising a plurality of extraction components.

[0202] 15. A system according to any of clauses 12 to 14, wherein each extraction member is a first extraction member and the system further comprises a second extraction member configured to extract the immersion fluid;

[0203] the second extraction member being positioned radially away from the inner surface of the fluid handling structure;

[0204] the second extraction member being positioned closer to the inner surface of the fluid handling structure than the meniscus control surface; and

[0205] The meniscus control surface is positioned between the first extraction member and the second extraction member.

[0206] 16. The system of clause 15, comprising a plurality of second extraction components.

[0207] 17. A system according to clause 15 or 16, wherein each second extraction member is configured such that, in use, substantially only liquid flows through the second extraction member.

[0208] 18. A system according to any of the preceding clauses, wherein, in the second operating state, the meniscus control surface is configured such that, in use, the meniscus moves relative to the meniscus control surface in response to movement of the substrate relative to the fluid handling system.

[0209] 19. A fluid handling system for a lithographic apparatus, wherein the fluid handling system is configured to confine an immersion fluid in a liquid confinement space between a portion of a projection system in the lithographic apparatus and a surface of a substrate, whereby a radiation beam projected from the projection system can illuminate the surface of the substrate by passing through the immersion fluid, the fluid handling system comprising:

[0210] a meniscus control surface and an extraction member, both configured to extract the immersion fluid;

[0211] wherein the meniscus control surface is configured to support a meniscus of the immersion fluid between the meniscus control surface and the surface of the substrate in a first operating state and a second operating state;

[0212] In the first operating state, the meniscus is secured to the meniscus control surface; and

[0213] In the second operating state, the meniscus is movable along the meniscus control surface.

[0214] 20. A fluid handling system for a lithographic apparatus, wherein the fluid handling system is configured to confine an immersion fluid in a liquid confinement space between a portion of a projection system in the lithographic apparatus and a surface of a substrate, whereby a radiation beam projected from the projection system can illuminate the surface of the substrate by passing through the immersion fluid, the fluid handling system comprising:

[0215] first and second extraction members, both configured to extract the immersion fluid; and

[0216] a meniscus control surface between the first extraction member and the second extraction member and configured to extract the immersion fluid;

[0217] wherein the meniscus control surface is configured to support a meniscus of immersion liquid between a surface of the meniscus control surface and the surface of the substrate.

[0218] 21. A lithographic apparatus comprising a fluid handling system according to any of the preceding clauses.

[0219] 22. The apparatus of clause 21, further comprising a positioning system configured to move a substrate holder relative to the projection system in a plane substantially parallel to the surface of the substrate, the substrate holder being configured to support the substrate.

[0220] 23. A device manufacturing method in a lithographic apparatus having a substrate holder configured to hold a substrate, a projection system configured to project a radiation beam onto the substrate held by the substrate holder, and a fluid handling system according to any of clauses 1 to 20, the method comprising:

[0221] using the fluid handling system to confine an immersion fluid in a space between at least a portion of the fluid handling system and the surface of the substrate;

[0222] projecting a patterned beam of radiation onto the substrate through the immersion fluid in the space;

[0223] supporting a meniscus of the immersion fluid between a meniscus control surface or damper of the fluid handling system and the substrate; and

[0224] moving the substrate in a scanning direction substantially perpendicular to the propagation direction of the radiation beam;

[0225] wherein, in a first operational state, the meniscus control surface is configured to maintain a meniscus of the immersion fluid substantially stationary between the meniscus control surface and the surface of the substrate; and

[0226] Wherein, in a second operational state, the meniscus control surface is configured to allow the meniscus of the immersion fluid to move relative to the meniscus control surface.

[0227] 24. A fluid handling system for a lithography device, wherein the fluid handling system is configured to confine an immersion fluid in a liquid confinement space between a portion of a projection system in the lithography device and a surface of a substrate, whereby a radiation beam projected from the projection system can irradiate the surface of the substrate by passing through the immersion fluid, the fluid handling system comprising an electrowetting structure; wherein: the electrowetting structure comprises one or more electrodes, the one or more electrodes being arranged to apply an electrowetting effect to at least a portion of a surface of the fluid handling system facing the substrate; and the one or more electrodes of the electrowetting structure are controllable to change the contact angle and / or contact line of the curved liquid surface of the immersion fluid.

[0228] 25. A lithographic apparatus comprising a fluid handling system according to clause 24.

[0229] Although specific embodiments of the present invention have been described above, it should be understood that the present invention may be practiced in a manner other than that 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 appended claims.

Claims

1. A fluid handling system for a lithographic apparatus, wherein the fluid handling system is configured to confine an immersion fluid in a liquid confinement space between a portion of a projection system in the lithographic apparatus and a surface of a substrate, whereby a radiation beam projected from the projection system can illuminate the surface of the substrate by passing through the immersion fluid, the fluid handling system comprising a meniscus control surface for controlling movement of a meniscus of the immersion fluid; in, in a first operational state, the meniscus control surface is configured to maintain a meniscus of the immersion fluid substantially stationary between the meniscus control surface and the surface of the substrate; and Wherein, in a second operational state, the meniscus control surface is configured to allow said movement of the meniscus of the immersion fluid.

2. The system of claim 1, further comprising a damper; in, In the second operational state, the damper is configured to support the movement of the meniscus of the immersion fluid between a surface of the damper and the surface of the substrate.

3. A system according to claim 1 or 2, wherein the curved liquid surface control surface comprises the surface of a microsieve or a porous member, and / or wherein the curved liquid surface control surface comprises a wetted surface, and / or further comprises a bypass flow path, which is configured to provide fluid flow along a side of the curved liquid surface control surface opposite to the substrate.

4. The system according to claim 3, further comprising: fluid an inlet, the fluid inlet being configured to supply a fluid flow to the bypass flow path; as well as The fluid outlet is configured to provide the fluid flow out of the bypass flow path. 5 . The system of claim 4 , further comprising a flow control system configured to control a flow rate of the fluid through the fluid outlet.

6. The system of claim 5, wherein the flow control system is configured to control the flow rate of the fluid through the fluid outlet to be a first fluid flow rate or a second fluid flow rate; The first fluid flow rate is greater than the second fluid flow rate; The first fluid flow rate is used to provide the first operating state; and The second fluid flow rate is used to provide the second operating state.

7. The system of any one of claims 3 to 6, wherein the fluid flow in the bypass flow path is a liquid flow.

8. A system according to any of the preceding claims, wherein the meniscus control surface is hydrophilic, and / or wherein the damper surface is hydrophobic, and / or wherein the damper is provided with an electrowetting structure, the electrowetting structure comprising one or more electrodes, the one or more electrodes being arranged to apply an electrowetting effect to at least a portion of the substrate-facing surface of the fluid handling system; and the one or more electrodes of the electrowetting structure are controllable so as to change the contact angle and / or contact line of the meniscus of the immersion fluid.

9. A system according to any one of the preceding claims, wherein: The system comprises a fluid handling structure having an inner surface configured to confine the immersion fluid; The system further comprises an extraction member configured to extract the immersion fluid; The meniscus control surface and the extraction member are positioned radially away from the inner surface of the fluid handling structure; and The extraction member is positioned further away from the inner surface of the fluid handling structure than the meniscus control surface, and / or Wherein, in the second operating state, the meniscus control surface is configured such that, in use, the meniscus moves relative to the meniscus control surface in response to movement of the substrate relative to the fluid handling system.

10. A system according to claim 9, wherein the extraction member is configured such that, in use, substantially only gas flows through the extraction member, and / or the extraction member comprises a plurality of extraction members.

11. A system according to claim 9 or 10, wherein each of the extraction members is a first extraction member and the system further comprises a second extraction member configured to extract the immersion fluid; the second extraction member being positioned radially away from the inner surface of the fluid handling structure; the second extraction member being positioned closer to the inner surface of the fluid handling structure than the meniscus control surface; and The meniscus control surface is positioned between the first extraction member and the second extraction member.

12. A system according to claim 11, comprising a plurality of second extraction members, and / or wherein each second extraction member is configured such that, in use, substantially only liquid flows through the second extraction member.

13. A fluid handling system for a lithographic apparatus, wherein the fluid handling system is configured to confine an immersion fluid in a liquid confinement space between a portion of a projection system in the lithographic apparatus and a surface of a substrate, whereby a radiation beam projected from the projection system can illuminate the surface of the substrate by passing through the immersion fluid, the fluid handling system comprising: a meniscus control surface and an extraction member, both configured to extract the immersion fluid; wherein the meniscus control surface is configured to support a meniscus of the immersion fluid between the meniscus control surface and the surface of the substrate in a first operating state and a second operating state; In the first operating state, the meniscus is secured to the meniscus control surface; and In the second operating state, the meniscus is movable along the meniscus control surface.

14. A fluid handling system for a lithographic apparatus, wherein the fluid handling system is configured to confine an immersion fluid in a liquid confinement space between a portion of a projection system in the lithographic apparatus and a surface of a substrate, whereby a radiation beam projected from the projection system can illuminate the surface of the substrate by passing through the immersion fluid, the fluid handling system comprising: a first extraction member and a second extraction member, both of the first extraction member and the second extraction member being configured to extract the immersion fluid; and a meniscus control surface between the first extraction member and the second extraction member and configured to extract the immersion fluid; wherein the meniscus control surface is configured to support a meniscus of immersion liquid between a surface of the meniscus control surface and the surface of the substrate.

15. A lithographic apparatus comprising a fluid handling system according to any preceding claim.

Images