Substrate support, lithographic apparatus, method of manipulating a charge distribution, and method of preparing a substrate

Abstract

The substrate support is configured to support a substrate. The substrate support includes a plurality of burls protruding from a base surface of the substrate support. The burls have tips in a plane for supporting the underside of the substrate with a gap between the base surface of the substrate support and the underside of the substrate. The substrate support includes a liquid supply channel for supplying a conductive liquid to the gap to fill the gap between the base surface of the substrate support and the underside of the substrate, thereby allowing charge to pass between the substrate support and the substrate. The substrate support has a controlled potential to manipulate the charge distribution on the underside of the substrate.

Description

Technical Field

[0001] Cross - reference to related applications

[0001] This application claims priority to European Patent Application No. 19209256.7, filed on November 14, 2019, the entire disclosure of which is incorporated herein by reference.

[0002]

[0002] The present invention relates to a substrate support, a lithographic apparatus, a method of manipulating a charge distribution, and a method of preparing a substrate.

Background Art

[0003]

[0003] A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs).

[0004]

[0004] The substrate is placed on a substrate table such that the desired pattern is applied to the substrate. The substrate table can be subject to aging degradation, particularly in immersion lithography.

[0005]

[0005] It is desirable to reduce the degradation of the substrate table.

Summary of the Invention

[0006]

[0006] According to an aspect of the present invention, there is provided a substrate support configured to support a substrate, the substrate support comprising: a plurality of bars protruding from a base surface of the substrate support and having tip portions in a plane for supporting a lower surface of the substrate with a gap provided between the base surface of the substrate support and the lower surface of the substrate; and a liquid supply channel for making charge passable between the substrate support and the substrate by supplying a conductive liquid to the gap to fill the gap between the base surface of the substrate support and the lower surface of the substrate, wherein the substrate support has a potential controlled such that it can manipulate the charge distribution on the lower surface of the substrate.

[0007]

[0007] According to an aspect of the present invention, there is provided a substrate support configured to support a substrate, the substrate support including a plurality of bars protruding from a base surface of the substrate support and having tip portions in a plane for supporting a lower surface of the substrate with a gap provided between the base surface of the substrate support and the lower surface of the substrate, and a vapor supply channel for allowing charges to pass between a region of the lower surface of the substrate and the bars by supplying vapor of a conductive liquid to a region of the lower surface of the substrate adjacent to the tip portions of at least one of the bars, the tip portions having a potential controlled so as to be able to manipulate a charge distribution on the lower surface of the substrate.

[0008]

[0008] According to an aspect of the present invention, there is provided a method of manipulating a charge distribution on a lower surface of a substrate, the method including supporting the lower surface of the substrate on a plurality of bars protruding from a base surface of a substrate support and having tip portions in a plane with a gap provided between the base surface of the substrate support and the lower surface of the substrate, and allowing charges to pass between the substrate support and the substrate by supplying a conductive liquid to the gap to fill the gap between the base surface of the substrate support and the lower surface of the substrate, the substrate support having a potential controlled so that the charge distribution on the lower surface of the substrate is manipulated.

[0009]

[0009] According to an aspect of the present invention, there is provided a method of manipulating a charge distribution on a lower surface of a substrate, the method including supporting the lower surface of the substrate on a plurality of bars protruding from a base surface of a substrate support and having tip portions in a plane with a gap provided between the base surface of the substrate support and the lower surface of the substrate, and allowing charges to pass between a region of the lower surface of the substrate and the bars by supplying vapor of a conductive liquid to a region of the lower surface of the substrate adjacent to the tip portions of at least one of the bars, the tip portions having a potential controlled so that the charge distribution on the lower surface of the substrate is manipulated.

[0010] According to one aspect of the present invention, there is provided a method of preparing a substrate to be exposed by a patterned radiation beam, the method comprising loading the substrate into a lithographic apparatus, supporting the substrate on a substrate support, drying the lower surface of the substrate, and moving the dried substrate to a substrate table where the upper surface, opposite to the lower surface of the substrate, is exposed to the patterned radiation beam.

Brief Description of the Drawings

[0011] Embodiments of the present invention will be described below with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, which are merely illustrative.

[0012]

Figure 1

Figure 2

Figure 3

[0013] A part of a lithographic apparatus according to an embodiment of the present invention is shown.

Figure 4

[0014] A substrate on a substrate support according to an embodiment of the present invention is shown.

Figure 5

[0015] The configuration of a substrate on a substrate support is shown.

Figure 6

[0015] The configuration of a substrate on a substrate support is shown.

Figure 7

[0016] Another configuration of a substrate on a substrate support is shown.

Figure 8

[0016] Another configuration of a substrate on a substrate support is shown.

Figures 9-10

[0017] The state in which the conductive liquid is removed from the configurations shown in FIGS. 5 and 6 is shown.

Figures 11-12

[0018] The state in which the conductive liquid is removed from the configurations shown in FIGS. 7 and 8 is shown.

Figure 13

[0019] Shows a substrate on a substrate support according to an embodiment of the present invention.

Figure 14

[0020] Shows the drying of the lower surface of a substrate on a substrate support according to an embodiment of the present invention.

Figure 15

[0020] Shows the drying of the lower surface of a substrate on a substrate support according to an embodiment of the present invention.

Figure 16

[0021] Shows a substrate on a substrate support according to an embodiment of the present invention.

Figure 17

[0022] Shows a substrate on a substrate support according to an alternative embodiment of the present invention.

Figure 18

[0023] Shows a substrate on a substrate support according to an alternative embodiment of the present invention.

Figure 19

[0024] Shows another view of a substrate support according to an embodiment of the present invention.

Figure 20

[0025] Shows another view of a substrate support according to an embodiment of the present invention.

Mode for Carrying Out the Invention

[0013]

[0026] Figure 1 schematically shows a lithographic apparatus 100 according to an embodiment of the invention. The lithographic apparatus 100 includes an illumination system (illuminator) IL configured to condition a radiation beam B (e.g., UV radiation or any other suitable radiation), and a mask support structure (e.g., a mask table) MT constructed to support a patterning device (e.g., a mask) MA and connected to a first positioning device PM configured to accurately position the patterning device according to certain parameters. The lithographic apparatus 100 also includes a substrate table (e.g., a wafer table) WT constructed to hold a substrate (e.g., a resist-coated wafer) W and connected to a second positioning device PW configured to accurately position the substrate W according to certain parameters. Further, the lithographic apparatus 100 includes a projection system (e.g., a refractive projection lens system) PS configured to project a pattern imparted to the radiation beam B by the patterning device MA onto a target portion C (e.g., including one or more dies) of the substrate W.

[0014]

[0027] The illumination system IL can include various types of optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof, for guiding, shaping, or controlling the radiation.

[0015]

[0028] The mask support structure MT supports, i.e., bears the weight of, the patterning device MA. The mask support structure MT holds the patterning device MA in a manner corresponding to the direction of the patterning device MA, conditions such as the design of the lithographic apparatus 100, for example, whether the patterning device MA is held in a vacuum environment or not. The mask support structure MT can use clamping techniques such as mechanical, vacuum, electrostatic, etc. to hold the patterning device. The mask support structure MT may be, for example, a frame or a table, and may be fixed or movable as required. The mask support structure MT can ensure that the patterning device MA comes to a desired position with respect to, for example, the projection system PS. When the terms "reticle" or "mask" are used in this specification, those terms can be regarded as synonymous with the more general term "patterning device".

[0016]

[0029] The term "patterning device" as used in this specification should be construed broadly to refer to any device that can be used to impart a pattern to a cross-section of the radiation beam B so as to generate a pattern on the target portion C of the substrate W. It should be noted that the pattern imparted to the radiation beam B may not exactly correspond to the desired pattern in the target portion C of the substrate W, for example, when the pattern includes phase shift features or so-called assist features. Assist features may be arranged on the patterning device MA so as to be able to pattern isolated and / or semi-isolated design features as if they were denser than they actually are. Generally, the pattern imparted to the radiation beam B will correspond to a particular functional layer of the device being generated in the target portion such as an integrated circuit.

[0017]

[0030] The patterning device MA may be transmissive or reflective. Examples of patterning devices include masks, programmable mirror arrays, and programmable LCD panels. Masks are well-known in lithography and include mask types such as binary masks, alternating phase shift masks, attenuated phase shift masks, and also various hybrid mask types. As an example of a programmable mirror array, a matrix array of small mirrors is used, and each mirror can be individually tilted so as to reflect an incident radiation beam in a different direction. The tilted mirrors impart a pattern to the radiation beam reflected by the mirror matrix.

[0018]

[0031] As used herein, the term "projection system" should be construed broadly to encompass any type of projection system PS, including, for example, refractive optical systems, reflective optical systems, catadioptric optical systems, magneto-optical systems, electro-magneto-optical systems, and electro-static optical systems, or any combination thereof, as appropriate in accordance with other factors such as the exposure radiation used, or the use of an immersion liquid or the use of a vacuum. When the term "projection lens" is used herein, this can be considered to be synonymous with the more general term "projection system".

[0019]

[0032] The illumination system IL may comprise an adjuster AD configured to adjust the angular intensity distribution of the radiation beam B. Usually, the outer and / or inner radius ranges of the intensity distribution in the pupil plane of the illumination system IL (generally referred to as σ-outer and σ-inner, respectively) can be adjusted. The illumination system IL may also comprise various other components such as an integrator IN and a condenser CN. The radiation beam B may be adjusted using the illumination system IL such that a desired uniformity and intensity distribution are obtained across its cross-section. The illumination system IL may or may not be considered to form part of the lithographic apparatus 100. For example, the illumination system IL may be an integral part of the lithographic apparatus 100 or it may be a separate component from the lithographic apparatus 100. In the latter case, the lithographic apparatus 100 may also be configured to allow the illumination system IL to be mounted thereon. Optionally, the illumination system IL may be detachable and provided separately (e.g., by the manufacturer of the lithographic apparatus or another supplier).

[0020]

[0033] As shown herein, the lithographic apparatus 100 is of the transmissive type (e.g., using a transmissive mask). Alternatively, the lithographic apparatus 100 may be of the reflective type (e.g., using a programmable mirror array of the type mentioned above or a reflective mask).

[0021]

[0034] The lithographic apparatus 100 may be of the type having two (dual-stage) or more substrate tables WT (and / or two or more mask support structures MT, e.g., a mask table). In such a “multi-stage” lithographic apparatus 100, additional substrate tables WT and / or mask support structures MT may be used in parallel or one or more other substrate tables WT and / or mask support structures MT may be used to perform preparatory steps while one or more substrate tables WT and / or mask support structures MT are being used for exposure.

[0022]

[0035] The patterning device MA is held in the mask support structure MT. The radiation beam B is incident on the patterning device MA. The radiation beam B is patterned by the patterning device MA. After being reflected from the patterning device MA, the radiation beam B passes through the projection system PS. The projection system PS focuses the radiation beam B onto the target portion C of the substrate W. The first positioner PM and the first position sensor (e.g., an interference device, a linear encoder, or a capacitance sensor) can be used to accurately position the patterning device MA with respect to the path of the radiation beam B. The first position sensor is not explicitly shown in FIG. 1. With the help of the second positioner PW and the second position sensor PS2 (e.g., an interference device, a linear encoder, or a capacitance sensor), the substrate table WT can be accurately moved, for example, to position different target portions C within the path of the radiation beam B.

[0023]

[0036] Generally, the movement of the mask support structure MT may be realized using a long-stroke module (coarse positioning) and a short-stroke module (fine positioning) that form part of the first positioning device PM. Similarly, the movement of the substrate table WT may also be realized using a long-stroke module and a short-stroke module that form part of the second positioner PW. In the case of a stepper (in contrast to a scanner), the mask support structure MT may be connected only to a short-stroke actuator or may be fixed. The patterning device MA may be aligned using mask alignment marks M 1 , M 2 . The substrate W may be aligned using substrate alignment marks P 1 , P 2 . The illustrated substrate alignment marks P 1 , P 2occupies a dedicated target portion C, but may be located between the target portions C (these are known as scribe line alignment marks). Similarly, in a situation where two or more dies are provided on the patterning device MA, the mask alignment marks M 1 , M 2 may be located between die and die.

[0024]

[0037] Immersion techniques can be used to increase the numerical aperture NA of the projection system PS. As shown in FIG. 1, in one embodiment, the lithographic apparatus 100 is of a type in which at least a portion of the substrate W can be covered with a liquid having a relatively high refractive index, such as water, so as to fill the space between the projection system PS and the substrate W. The immersion liquid may also be added, for example, to other spaces of the lithographic apparatus 100 between the patterning device MA and the projection system PS. As used herein, the term "immersion" does not mean that a structure such as the substrate W must be immersed in a liquid, but only means that the liquid is located between the projection system PS and the substrate W during exposure.

[0025]

[0038] Referring to FIG. 1, the illuminator IL receives a radiation beam from the source module SO. For example, when the source module SO is an excimer laser, the source module SO and the lithographic apparatus 100 may be separate. In such a case, the source module SO is not considered to form part of the lithographic apparatus 100, and the radiation is transferred from the source module SO to the illumination system IL using the beam delivery system BD. In one embodiment, the beam delivery system BD comprises, for example, suitable guiding mirrors and / or a beam expander. In another case, when the source module SO is, for example, a mercury lamp, the source module SO may be an integral part of the lithographic apparatus 100. The source module SO and the illumination system IL, together with the beam delivery system BD if required, may sometimes be referred to as the radiation system.

[0026]

[0039] The configurations that provide liquid between the final element of the projection system PS and the substrate W can be broadly classified into three types. These are the bath configuration, the so-called local immersion system, and the all-wet immersion system. In the bath configuration, substantially the entire substrate W and optionally a part of the substrate table WT are immersed in a liquid bath.

[0027]

[0040] As shown in FIG. 1, the liquid supply system is provided with a liquid confinement structure IH that extends along at least a part of the boundary of the space between the final element of the projection system PS and the substrate W, the substrate table WT, or both of them. Such a configuration is shown in FIG. 2. The configuration shown in FIG. 2 and described later may be applied to the lithographic apparatus shown in FIG. 1 above.

[0028]

[0041] FIG. 2 schematically shows a local liquid supply system or a fluid handling system having a liquid confinement structure IH. The liquid confinement structure IH extends along at least a part of the boundary of the space 11 between the final element of the projection system PS and the substrate table WT or the substrate W. (In the following text, it should be noted that unless otherwise explicitly stated, references to the surface of the substrate W are also, additionally or alternatively, references to the surface of the substrate table WT.) In one embodiment, a seal is formed between the liquid confinement structure IH and the surface of the substrate W. This seal may be a non-contact seal such as a gas seal 16 (a system having such a gas seal is disclosed in European Patent Application Publication No. EP-A-1,420,298) or a liquid seal.

[0029]

[0042] The liquid confinement structure IH confines liquid at least partially in the space 11 between the final element of the projection system PS and the substrate W. The space 11 is at least partly formed by a liquid confinement structure IH which is arranged below the final element of the projection system PS and surrounds this final element. The liquid is supplied by a liquid inlet / outlet 13 to the space 11 below the projection system PS and inside the liquid confinement structure IH. The liquid may be removed by the liquid inlet / outlet 13. In certain embodiments, depending on the scan direction, one of the two liquid inlets / outlets 13 supplies liquid while the other liquid inlet / outlet 13 removes liquid. At least one of the two inlets / outlets 13 may be arranged above or below the bottom surface of the final element of the projection system PS.

[0030]

[0043] The liquid may be confined in the space 11 by a gas seal 16. In use, the gas seal 16 is formed between the bottom of the liquid confinement structure IH and the surface of the substrate W. The gas of the gas seal 16 is provided under pressure via an inlet 15 into the gap between the liquid confinement structure IH and the substrate W. The gas is withdrawn via an outlet 14. The overpressure at the gas inlet 15, the vacuum level at the outlet 14 and the geometry of the gap are configured such that there is a high-speed gas flow towards the inside confining the liquid. The force of the gas acting on the liquid between the liquid confinement structure IH and the substrate W confines the liquid in the space 11. Such a system is disclosed in US Patent Application Publication No. US-2004-0207824, which is hereby incorporated by reference in its entirety. In certain embodiments, the liquid confinement structure IH does not have a gas seal.

[0031]

[0044] In a local area liquid supply system, the substrate W moves under the projection system PS and the liquid supply system. When an end of the substrate W is imaged, the end of the substrate W (or another object) will pass under the space 11. When a sensor on the substrate table WT (or on the measurement table) is imaged, the end of the substrate W (or another object) will pass under the space 11. A dummy substrate or a so-called closing plate can be arranged under the liquid supply system, for example, so that substrate exchange can be performed. When the substrate table WT moves so that a dummy substrate or a so-called closing plate can be arranged under the liquid supply system, the end of the substrate W (or another object) will pass under the space 11. Liquid may leak into the gap between the substrate W and the substrate table WT. This liquid may be pushed under the force of hydrostatic pressure or hydrodynamic pressure or a gas knife or other gas flow generating device.

[0032]

[0045] FIG. 3 is a side cross-sectional view showing a further liquid supply system or fluid handling system according to an embodiment. The configuration shown in FIG. 3 described below may be applied to the lithographic apparatus 100 shown in FIG. 1 above. The liquid supply system comprises a liquid confinement structure IH extending along at least a part of the boundary of the space 11 between the final element of the projection system PS and the substrate table WT or the substrate W. (It should be noted that, unless otherwise specified, the following description regarding the surface of the substrate W also means, additionally or alternatively, the surface of the substrate table WT.)

[0033]

[0046] The liquid confinement structure IH confines liquid at least partially in the space 11 between the final element of the projection system PS and the substrate W. The space 11 is at least partly formed by a liquid confinement structure IH which is arranged below the final element of the projection system PS and surrounds this final element. In certain embodiments, the liquid confinement structure IH includes a body member 53 and a porous member 83. The porous member 83 is plate-shaped and has a plurality of holes (i.e., openings or pores). In certain embodiments, the porous member 83 is a mesh plate in which a large number of small holes 84 are formed in a mesh pattern. Such a system is disclosed in US Patent Application Publication No. US2010 / 0045949A1, which is hereby incorporated by reference in its entirety.

[0034]

[0047] The body member 53 includes a supply port 72 through which liquid can be supplied to the space 11, and a recovery port 73 through which liquid can be recovered from the space 11. The supply port 72 is connected to a liquid supply device 75 via a passage 74. The liquid supply device 75 can supply liquid to the supply port 72. The liquid supplied from the liquid supply device 75 is supplied to each supply port 72 through the corresponding passage 74. The supply port 72 is arranged at a predetermined position of the body member 53 facing the optical path near the optical path. The recovery port 73 can recover liquid from the space 11. The recovery port 73 is connected to a liquid recovery device 80 via a passage 79. The liquid recovery device 80 includes a vacuum system and can recover liquid by sucking the liquid through the recovery port 73. The liquid recovery device 80 recovers the liquid LQ recovered through the passage 79 via the recovery port 73. The porous member 83 is arranged at the recovery port 73.

[0035]

[0048] In one embodiment, in order to form a space 11 having liquid on one side between the projection system PS and the liquid confinement structure IH, and on the other side between the substrate W, the liquid is supplied from the supply port 72 to the space 11, and the pressure in the recovery chamber 81 within the liquid confinement structure IH is adjusted to a negative pressure so as to recover the liquid through the holes 84 (i.e., the recovery ports 73) of the porous member 83. By performing the liquid supply operation using the supply port 72 and the liquid recovery operation using the porous member 83, a space 11 is formed between the projection system PS, the liquid confinement structure IH on one side, and the substrate W on the other side.

[0036]

[0049] When using the lithographic apparatus 100, various lithographic processes and process steps are performed on the substrate W. The substrate W may be cleaned, for example, by wet chemical treatment. The substrate W may be heated to a temperature sufficient to drive out moisture that may be present on the surface of the substrate W. The substrate W may be covered with a layer of resist (e.g., photoresist). The substrate W may be pre-baked to drive out excess photoresist solvent. And the substrate W is exposed so that the pattern in the radiation beam B is transferred onto the substrate W. Thereafter, development, etching, and resist removal may be performed on the substrate W. These steps may be repeated for further layers on the substrate W.

[0037]

[0050] As shown in FIG. 1, in one embodiment, the lithographic apparatus 100 comprises a substrate table WT. The substrate table WT is configured to support the substrate W for the exposure process. In the exposure process, the substrate W is exposed to the radiation beam B through a liquid (i.e., the immersion liquid) in order to form a pattern on the substrate W.

[0038]

[0051] In one embodiment, the lithography apparatus 100 comprises a receiving unit. The receiving unit may be part of a substrate handler that controls the movement of the substrate W within the lithography apparatus 100. When the substrate W is introduced into the lithography apparatus 100, the substrate W is first placed on the receiving unit. Subsequently, after the substrate W has moved from the receiving unit, it is placed on the substrate table WT for the exposure process. Thus, the substrate W is placed on the receiving unit before moving onto the substrate table WT.

[0039]

[0052] In one embodiment, the receiving unit comprises a substrate support 20. FIG. 4 shows the substrate W on the substrate support 20. The substrate support 20 is configured to support the substrate W.

[0040]

[0053] As shown in FIG. 4, the substrate support 20 comprises a body 21. The body 21 has a plate-like shape and may be substantially the same shape as the substrate W. For example, when the substrate W is circular, the body 21 may correspondingly be circular. However, the shape of the body 21 is not particularly limited. The body 21 has an upper surface that forms the base surface 23 of the substrate support 20. In one embodiment, the base surface 23 of the substrate support 20 is conductive. In one embodiment, the substrate support 20 includes a coating for the base surface 23. The coating has a fairly low electrical resistance. In some embodiments, the coating is electrically dissipative. For example, in one embodiment, the coating has a resistance of up to 100 MΩ. In one embodiment, the coating has an electrical resistance of at least 10 kΩ. In one embodiment, the coating includes diamond-like carbon, silicon carbide (such as silicon infiltrated silicon carbide) and / or chromium nitride.

[0041]

[0054] As shown in FIG. 4, in one embodiment, the substrate support 20 includes a plurality of bars 22. The bars 22 protrude from the base surface 23 of the substrate support 20. The bars 22 have tip portions 24. The tip portions 24 are at the ends of the bars 22 opposite to the ends where the bars 22 are connected to the base surface 23 of the substrate support 20. The tip portions 24 of the bars 22 are in a plane for supporting the lower surface 25 of the substrate W.

[0042]

[0055] The lower surface 25 of the substrate W is flat regardless of whether the base surface 23 of the substrate support 20 is flat. When the base surface 23 of the substrate support 20 is flat, all of the bars 22 may have the same height. In an alternative embodiment, the base surface 23 is not flat. The base surface 23 may have, for example, a conical or bowl shape. When the base surface 23 is not flat, the bars 22 may have different heights depending on their positions on the base surface 23.

[0043]

[0056] As shown in FIG. 4, in one embodiment, a gap 26 is formed between the base surface 23 of the substrate support 20 and the lower surface 25 of the substrate W. The bars 22 extend across the gap 26 between the base surface 23 of the substrate support 20 and the lower surface 25 of the substrate W. The gap 26 exists between the bars 22.

[0044]

[0057] In one embodiment, the substrate W is configured to be clamped onto the bars 22 by a negative pressure, such as a vacuum. The gap 26 may have a pressure lower than the pressure above the substrate W. The pressure difference between above and below the substrate W tends to clamp the substrate W onto the substrate support 20. The size of the gap 26 is not particularly limited. As just one example, the gap 26 may be in the range of about 5 μm to about 200 μm. The size of the gap 26 may match the height of the bars 22.

[0045]

[0058] As shown in FIG. 4, in one embodiment, the substrate support 20 includes a liquid supply channel 28. The liquid supply channel 28 is for supplying the conductive liquid 27 to the gap 26. The conductive liquid 27 fills the gap 26 between the base surface 23 of the substrate support 20 and the lower surface 25 of the substrate W. This enables charges to pass between the substrate support 20 and the substrate W. The charges can pass through the conductive liquid 27 between various portions of the lower surface 25 of the substrate W. The charge distribution on the lower surface 25 of the substrate W may change as a result of the presence of the conductive liquid 27. The charge distribution may tend to be uniform across the lower surface 25 of the substrate W. In one embodiment, the liquid supply channel 28 is configured to supply a gas that condenses the conductive medium to the lower surface 25 of the substrate W.

[0046]

[0059] In one embodiment, the substrate support 20 has a controlled potential so as to be able to manipulate the charge distribution on the lower surface 25 of the substrate W. For example, as shown on the left side of FIG. 4, in one embodiment, the substrate support 20 is electrically grounded. When charges pass between the substrate support 20 and the substrate W, the lower surface 25 of the substrate W tends to reach the same potential as the substrate support 20. For example, the lower surface 25 of the substrate W may reach the ground potential when charges can pass through the conductive liquid 27 to / from the substrate support 20.

[0047]

[0060] With the substrate support 20 being electrically grounded, charges can be removed from the lower surface 25 of the substrate W through the conductive liquid 27 filling the gap 26. However, it is not essential for the substrate support 20 to be electrically grounded. In an alternative embodiment, the substrate support 20 is electrically biased. With the substrate support 20 being electrically biased, charges redistributed to the lower surface 25 of the substrate W can be provided through the conductive liquid 27 filling the gap 26. By controlling the potential of the substrate support 20, it is possible to manipulate the charge distribution on the lower surface 25 of the substrate W. In one embodiment, the substrate support 20 is controlled to have the same potential as the pedestal or pins supporting the substrate W when the substrate W is loaded onto or unloaded from the substrate support 20.

[0048]

[0061] When the substrate W moves onto the substrate table WT (e.g., for an exposure process), its lower surface 25 has substantially grounded charges (or redistributed charges). This reduces the likelihood of the substrate table WT being oxidized when the substrate W is placed on the substrate table WT.

[0049]

[0062] In one embodiment, the substrate table WT includes a bar for supporting the lower surface 25 of the substrate W. The top of the bar of the substrate table WT may oxidize in the presence of moisture and charges. By reducing the charges on the lower surface 25 of the substrate W, the oxidation process is reduced. Some embodiments of the present invention are expected to reduce the deterioration of the substrate table WT.

[0050]

[0063] In one embodiment, the substrate support 20 includes a thermal conditioner configured to thermally condition the substrate W. In one embodiment, the substrate W is on the substrate support 20 while being thermally conditioned. For example, the substrate W may be on the substrate support 20 for about 10 seconds for thermal conditioning. In one embodiment, the process of manipulating the charge distribution through the conductive liquid 27 on the lower surface 25 of the substrate W is performed while the substrate W is being thermally conditioned. The substrate W is thermally conditioned in preparation for the exposure process. For example, the substrate W may be heated, cooled, or may have a uniform temperature across its lower surface 25.

[0051]

[0064] FIGS. 5 and 6 show the substrate W on the substrate support 20 according to an embodiment of the present invention. FIG. 5 shows a plan view from above the substrate support 20. The substrate W is not shown in FIG. 5. FIG. 6 shows a side view of the radius of the substrate W and the substrate support 20. In FIG. 6, the axis Q represents the center points of the substrate W and the substrate support 20.

[0052]

[0065] As shown in FIGS. 5 and 6, in one embodiment, the substrate support 20 has a hole in its center. The hole may be used to allow a cylinder to pass through for raising and lowering the substrate W relative to the substrate support 20 (e.g., for loading and unloading the substrate W). However, it is not essential for such a hole to be provided at the center of the substrate support 20. In an alternative embodiment, the center of the substrate support 20 is filled, and a plurality of holes are provided at a certain radius of the substrate support 20. These holes may be used to allow pins to control the loading and unloading of the substrate W.

[0053]

[0066] As shown in FIG. 6, in one embodiment, the substrate support 20 includes a chamber 33. The chamber 33 is configured to be filled with a sufficient amount of the conductive liquid 27. The conductive liquid 27 is stored in the chamber 33 and is released when the conductive liquid 27 is injected into the gap 26.

[0054]

[0067] As shown in FIGS. 5 and 6, in one embodiment, the conductive liquid 27 fills the gap 26 over most of the lower surface 25 of the substrate W. As shown in FIGS. 5 and 6, in one embodiment, the conductive liquid 27 is injected to create a complete conductive layer between the substrate W and the substrate support 20. The conductive layer forms a conductive bridge between the substrate W and the substrate support 20. In one embodiment, the conductive liquid 27 fills the gap 26 over substantially the entire lower surface 25 of the substrate W. Of course, there may be small portions of the lower surface 25 of the substrate W that are not covered by the conductive liquid 27. For example, there may be no conductive liquid at the very outer periphery or the center of the lower surface 25. The charge can be made uniform over substantially the entire lower surface 25 of the substrate W. Certain embodiments of the present invention are expected to reduce degradation over most or substantially the entire substrate table WT.

[0055]

[0068] As described above, in one embodiment, the substrate W is clamped on the substrate support 20. In one embodiment, the conductive liquid 27 is applied between the substrate W and the substrate support 20 before the substrate W is clamped on the substrate support 20 (e.g., by applying a negative pressure to the gap 26). Additionally or alternatively, in one embodiment, the conductive liquid 27 is applied during the clamping of the substrate W onto the substrate support 20. The conductive liquid 27 can be applied before the load / clamping of the substrate W and / or supplied during the clamping of the substrate W via the liquid supply channel 28.

[0056]

[0069] As shown in FIG. 6, in one embodiment, the substrate support 20 includes a gas supply channel 31. The gas supply channel 31 is configured to supply gas to the gap 26. For example, the gas may be supplied to the gap 26 to displace the conductive liquid 27 from the gap 26. In one embodiment, the gas supply channel 31 is configured to supply gas to dry the lower surface 25 of the substrate W.

[0057]

[0070] As shown in FIG. 6, in one embodiment, the liquid supply channel 28 and the gas supply channel 31 share a common opening 32 in the base surface 23 of the substrate support 20. The channels can be controlled to control which of the gas and the conductive liquid 27 is supplied from the common opening 32 to the gap 26. However, it is not essential to provide the common opening 32. In an alternative embodiment, independent supply channels are provided for supplying the gas and for supplying the conductive liquid 27.

[0058]

[0071] As shown in FIG. 6, in one embodiment, the substrate support 20 includes valves 34-36 for controlling the conductive liquid 37 and gas supplied to the common opening 32. For example, as shown in FIG. 6, in one embodiment, the substrate support 20 includes a first valve 34 at the upstream end of the chamber 33. The first valve 34 is configured to control the flow of the conductive liquid 27 into the chamber 33 in which the conductive liquid 27 is stored. The first valve 34 may be referred to as a droplet generator. In one embodiment, the substrate support 20 includes a second valve 35. The second valve 35 is disposed at the downstream end of the chamber 33. The second valve 35 controls the flow of the conductive liquid 27 from the chamber 33 to the common opening 32. In one embodiment, the substrate support 20 includes a third valve 36. The third valve 36 is configured to control the flow of gas to the common opening 32.

[0059]

[0072] In an alternative embodiment, the liquid supply channel 28 and the gas supply channel 31 do not share a common opening. The liquid supply and the gas supply may be provided from separate supply sections. In such an alternative embodiment, the valve arrangement may be different from the arrangement shown in FIG. 6. Valves may be provided for independently controlling the liquid supply and the gas supply.

[0060]

[0073] As described above, in certain embodiments, the conductive liquid 27 is supplied before clamping the substrate W onto the substrate support 20. For example, in certain embodiments, the conductive liquid 27 is supplied to the gap 26 by closing the third valve 36 for a short time and opening the first valve 34 and the second valve 35. The liquid supply channel 28 may have an overpressure for forming an annular flow of the conductive liquid 27 in the region of the common opening 32. The supply of the conductive liquid 27 can be stopped by closing the first valve 34 and the second valve 35. Subsequently, as a result of clamping the substrate W onto the substrate support 20, the annular flow of the conductive liquid 27 is pushed so that the conductive liquid 27 spreads along the lower surface 25 of the substrate W.

[0061]

[0074] Alternatively, the substrate W may be clamped to the substrate support 20 before the conductive liquid 27 is supplied to the gap 26. For example, as shown in FIGS. 5 and 6, in certain embodiments, the substrate support 20 includes an inner extraction channel 29 and an outer extraction channel 30. The inner extraction channel 29 and the outer extraction channel 30 are connected to a negative pressure, for example, for clamping, to remove substances from the gap 26. In certain embodiments, the extraction channels 29, 30 are used to clamp the substrate W to the substrate support 20 while the second valve 35 and the third valve 36 are closed. Subsequently, the first valve 34 and the second valve 35 are opened for a short time to supply a certain amount of the conductive liquid 27 into the gap 26. The conductive liquid 27 spreads into the gap 26 across the lower surface 25 of the substrate W. Then the second valve 35 and optionally the first valve 34 are closed to stop the supply of the conductive liquid 27. This results in a complete or partial wet area between the substrate W and the substrate support 20 as shown in FIGS. 5 and 6.

[0062]

[0075] In a configuration alternative to the configuration shown in FIGS. 5 and 6, the conductive liquid 27 is injected to generate a conductive annular liquid layer that forms a conductive bridge between the substrate W and the substrate support 20. FIGS. 7 and 8 show such a configuration in which the substrate W is disposed on the substrate support 20.

[0063]

[0076] In any configuration, in the area where the conductive liquid 27 fills the gap between the lower surface of the substrate W and the substrate support 20, there is a possibility that charges are discharged to the substrate support 20. The flow of charges depends on the bias potential and the conductivity of the conductive liquid. In one embodiment, the conductive liquid 27 is conductive enough so that the charges are substantially completely discharged towards the ground storage unit. In an alternative embodiment, a bias potential is applied to the substrate support 20 so that the remaining net charge is evenly distributed in the area where the conductive liquid 27 fills the gap 26. The average net charge corresponds to the potential applied to the substrate support 20. For example, in one embodiment, the substrate W is charged to ensure a net potential greater than the open circuit potential of the electrochemical open circuit, and as a result, oxidation does not occur. One embodiment is expected to reduce or prevent oxidation of the substrate table WT.

[0064]

[0077] As shown in FIGS. 7 and 8, in one embodiment, an annular layer of the conductive liquid 27 is disposed radially inside and radially outside the common opening 32 of the liquid supply channel 28. As shown in FIGS. 7 and 8, the gap 26 is not filled over most of the lower surface 25 of the substrate W. FIGS. 7 and 8 show unfilled sections 37. As shown in FIGS. 7 and 8, in one embodiment, the unfilled section 37 is radially inside the annular layer of the conductive liquid 27. As shown in FIGS. 7 and 8, in one embodiment, the unfilled section 37 is radially outside the annular layer of the conductive liquid 27. However, this is not necessarily the case. In an alternative embodiment, the annular layer of the conductive liquid 27 is on the outer periphery of the lower surface 25 of the substrate W so that there is no large unfilled section 37 radially outside the annular layer. In a further alternative embodiment, the annular layer of the conductive liquid 27 is closer to the center of the lower surface 25 of the substrate W so that there is no large unfilled section 37 radially inside the annular layer of the conductive layer 27.

[0065]

[0078] In one embodiment, the conductive liquid 27 is supplied to the gap 26 to form one or more control segments in which the gap 26 is filled with the conductive liquid 27. For example, in one embodiment, the conductive liquid 27 is supplied to form a plurality of concentric rings. The position of the segment may be controlled based on locations on the lower surface 25 of the substrate W where charges are known to be undesirable. Other portions of the lower surface 25 of the substrate W may be uncharged or, for example, have a charge that is acceptably low. Certain embodiments of the present invention are expected to reduce the time required to adequately manipulate the charges on the lower surface 25 of the substrate W.

[0066]

[0079] In one embodiment, the conductive liquid 27 remains substantially stationary while charges flow between the substrate W and the substrate support 20. This means that the area where the conductive liquid 27 fills the gap 26 remains substantially unchanged during the manipulation of the charge distribution on the lower surface 25 of the substrate W. However, this is not necessarily the case. In an alternative embodiment, the conductive liquid 27 moves. For example, in one embodiment, the conductive liquid 27 moves radially along the lower surface 25 of the substrate W across the gap 26. The conductive liquid 27 is sufficiently conductive such that charges flow between the substrate W and the substrate support 20 while the conductive liquid 27 fills the gap 26 in each area. For example, in one embodiment, gas 38 is supplied to the gap 26 to move the conductive liquid 27 radially within the gap 26. When the conductive liquid 27 moves and contacts a charged location on the lower surface 25 of the substrate W, charges pass between that charged location and the base surface 23 of the substrate support 20. For example, the conductive liquid 27 may be removed by injecting the gas 38 after injecting the conductive liquid 27. The gas 38 forms an annular bubble that pushes the conductive liquid 27 radially. For example, the bubble may push the conductive liquid 27 radially inward and outward toward the inner extraction channel 29 and the outer extraction channel 30 of the substrate support 20.

[0067]

[0080] In an alternative embodiment, the substrate W and the body of the conductive liquid 27 move relative to each other in rotational movement and / or translational movement. For example, the substrate W may rotate and / or translate relative to the substrate support 20. The body of the conductive liquid 27 forms the edge of the liquid. In certain embodiments, the body of the conductive liquid 27 is continuously refreshed. In certain embodiments, the body of the conductive liquid 27 is bounded by at least one extraction channel 29, 30 and / or at least one gas supply channel 31. In certain embodiments, the lower surface 25 of the substrate W is coated with a coating (described below) behind the body of the conductive liquid 27. The body of the conductive liquid 27 may be formed as a liquid wall.

[0068]

[0081] In certain embodiments, the lower surface 25 of the substrate W comprises at least one groove (not shown). In certain embodiments, the conductive liquid 27 is supplied to the groove and flows along the groove. The conductive liquid 27 may be extracted from another position of the groove. For example, the conductive liquid 27 may be supplied to one end of the groove and extracted from the other end of the groove. In certain embodiments, a gas such as clean dry air (CDA), extreme clean dry air (XCDA) or nitrogen is supplied to the groove following the conductive liquid 27. The gas flow path may be the same as the flow path of the conductive liquid 27. In certain embodiments, a coating (described below) is applied to the groove following the gas. The flow path of the coating material may be the same as the gas flow path. In certain embodiments, the coating is applied in liquid form.

[0069]

[0082] In certain embodiments, one or more grooves are configured such that, in combination with the relative movement of the substrate W and the substrate support 20, fluid is extruded through the grooves. In certain embodiments, the grooves have a cross-sectional shape that varies along the length of the grooves. This may help to accommodate changes in the relative linear velocity of the substrate W and the substrate support 20. Such changes in relative linear velocity may occur when the substrate W rotates relative to the substrate support 20.

[0070]

[0083] In one embodiment, the conductive liquid 27 is locally applied to one or more areas of the lower surface 25 of the substrate W without directly applying the conductive liquid 27 over the entire lower surface 25. In one embodiment, the conductive liquid 27 spreads over the lower surface 25 due to the movement of the substrate W. In one embodiment, a gas bearing is used between the one or more areas to which the conductive liquid 27 is applied. The gas bearing is configured to control the height of the lower surface 25 above the substrate support 20. This may help to maintain any one or more grooves at a controlled height above the substrate support 20.

[0071]

[0084] As shown in FIGS. 5 and 6 and described above, in one embodiment, a complete conductive layer may be formed between the substrate W and the substrate support 20. Charge may be discharged towards the substrate support 20 from the moment the area between the lower surface 25 of the substrate W and the substrate support 20 gets wet. Alternatively, when an annular layer of the conductive liquid 27 is formed (as shown in FIGS. 7 and 8), charge discharge occurs when the annular layer of the conductive liquid 27 is forced through the gap 26.

[0072]

[0085] In one embodiment, the substrate W is prepared for exposure by a patterned radiation beam. The method includes loading the substrate W into the lithographic apparatus 100. The substrate W is then supported on the substrate support 20. In one embodiment, the substrate support 20 is stationary. The substrate support 20 is not part of the lithographic apparatus 100 that is controlled to move during use.

[0073]

[0086] As will be described in more detail below, in one embodiment, the method includes drying the lower surface 25 of the substrate W before the dried substrate W is moved to a substrate table WT on which exposure with a patterned radiation beam is performed on the upper surface opposite to the lower surface 25 of the substrate W. By drying the lower surface 25 of the substrate W before the substrate W is placed on the substrate table WT, the substrate W has less moisture on its lower surface 25. When the substrate W is loaded onto the substrate table WT, there is less moisture in contact with the substrate table WT. One embodiment of the present invention is expected to reduce the deterioration of the substrate table WT. Specifically, one embodiment of the present invention is expected to reduce the oxidation of the substrate table WT.

[0074]

[0087] In one embodiment, the lower surface 25 of the substrate W is dried by applying a deep vacuum to the gap 26 between the substrate W and the substrate support 20. Optionally, the gap 26 may be purged with a moisture-free gas to better remove moisture. For example, the moisture-free gas may be supplied from the gas supply channel 31. In one embodiment, a deep vacuum is applied by extracting gas through the inner extraction channel 29 and / or the outer extraction channel 30. The deep vacuum is a pressure lower than the pressure required to clamp the substrate W to the substrate support 20. When the substrate W is clamped on the substrate support 20, a negative pressure is provided in the gap 26. However, this negative pressure is not low enough to remove water from the lower surface 25 of the substrate W. In contrast, when a deep vacuum is applied, moisture is removed from the lower surface 25. Drying is achieved by applying a negative pressure to the gap 26 between the lower surface 25 of the substrate W and the base surface 23 of the substrate support 20 to remove droplets from the lower surface 25 of the substrate W. Drying may be pressure-induced. In one embodiment, a negative pressure is applied to the gap 26 to remove all liquids (e.g., water) from the lower surface 25 of the substrate W. For example, a liquid film may be removed from the lower surface 25 of the substrate W.

[0075]

[0088] In some embodiments, the process of manipulating the charge distribution is performed without drying the substrate W. In alternative embodiments, the drying process is performed without manipulating the charge distribution. In still further alternative embodiments, both the charge distribution manipulation and the drying process are performed. In such embodiments, the manipulation of the charge distribution is first performed using the conductive liquid 27. The conductive liquid 27 is then removed. For example, gas 38 may be provided through the gas supply channel 31 to remove the conductive liquid 27 from the gap 26. In one embodiment, the gas 38 supplied to the gap 26 is clean dry air (CDA), extreme clean dry air (XCDA), nitrogen, or moisture-free gas. In one embodiment, the conductive liquid 27 includes IPA. IPA evaporates faster than water. Certain embodiments of the present invention are expected to reduce the effect of evaporation on the substrate W.

[0076]

[0089] In the figure, the gas supply channel 31 is shown at an intermediate radius. However, this is not necessarily the case. In alternative embodiments, the gas supply channel 31 may be near the center of the substrate support 20 or at the outer periphery of the substrate support 20.

[0077]

[0090] In one embodiment, the conductive liquid 27 is pushed towards the inner extraction channel 29 and / or the outer extraction channel 30. FIGS. 9 and 10 show the gas 38 pushing the conductive liquid 27 towards the extraction channels 29, 30. The conductive liquid 27 is removed from the gap 26 through the extraction channels 29, 30.

[0078]

[0091] FIG. 13 shows a further possible feature of the configuration between the substrate W and the substrate support 20. As shown in FIG. 13, in one embodiment, the base surface 23 of the substrate support 20 is shaped such that the gap 26 narrows towards the extraction channel 30. This enables the capillary effect to facilitate or simplify the movement of the conductive liquid 27 towards the extraction channel, for example the outer extraction channel 30. In one embodiment, the base surface 23 is hydrophilic. In one embodiment, the lower surface 25 of the substrate W is hydrophilic. As shown in FIG. 13, in one embodiment, a geometry configuration such as a wedge is formed for the gap 26.

[0079]

[0092] FIGS. 11 and 12 show the manner in which the gas 38 is supplied to extrude the conductive liquid 27 from the gap 26. FIGS. 11 and 12 show the conductive liquid 27 being pushed through the gap 26 when the conductive liquid 27 forms an annular layer as shown in FIGS. 7 and 8. In contrast, FIGS. 9 and 10 correspond to the configuration in which the entire layer of the conductive liquid 27 is formed as shown in FIGS. 5 and 6.

[0080]

[0093] In one embodiment, the drying of the lower surface 25 of the substrate W may be by flow induction. In one embodiment, the drying is by supplying a gas flow to the gap 26 between the lower surface 25 of the substrate W and the base surface 23 of the substrate support 20 from the substrate support 20. For example, a strong flow of moisture-free gas may dry the substrate W. The gas may be supplied via the gas supply channel 31.

[0081]

[0094] In one embodiment, the gas flow provides a gas film for supporting the substrate W above the substrate support 20 without the substrate W contacting the substrate support 20. When exceeding a certain flow rate, a gas bearing is formed and the substrate W is peeled off from the bead 22 of the substrate support 20. The substrate W floats on the gas film above the bead 22. In one embodiment, the gas 38 continues to be extracted through the extraction channels 29, 30 so as to maintain a negative pressure sufficient to hold the substrate W on the bead 22 or to hold the substrate W at a limited floating height above the bead 22. In one embodiment, the gas 38 is extracted through the extraction channels 29, 30 to extract all of the supplied flow. By providing a gas film for supporting the substrate W without contacting the substrate support 20, any influence of the bead 22 on the charge distribution or the drying of the substrate W can be reduced. In one embodiment, the substrate support W is designed as a gas bearing in which a large flow of pure radially directed gas dries the lower surface 25 of the substrate W.

[0082]

[0095] As described above, in one embodiment, the substrate support 20 includes the bead 22. However, this is not necessarily the case. In an alternative embodiment, the substrate support 20 does not have the bead 22. The substrate support 20 may have the form of a flat plate having only supply and extraction channels. The substrate support 20 is configured not to contact the substrate W during use. In one embodiment, the substrate support 20 is configured to thermally condition the substrate W and dry the lower surface of the substrate W. The substrate support 20 may not be configured to manipulate the charge distribution by using the conductive liquid 27. This reduces the risk of capillary clamping, which may make it more difficult to remove the liquid in a short time.

[0083]

[0096] In one embodiment as described above, the conductive liquid 27 is removed by injecting the gas 38 after injecting the conductive liquid 27. The gas 38 pushes the conductive liquid 27 through the gap 26. In one embodiment, the gas 38 is a vapor of an organic liquid soluble in the conductive liquid 27 and includes a vapor that dissolves in the meniscus 39 (e.g., shown in FIG. 12) of the conductive liquid 27 while the meniscus 39 crosses the lower surface 25 of the substrate W. This promotes drying of the lower surface 25 of the substrate W. For example, in one embodiment, isopropyl alcohol (IPA) vapor is added to the gas 38. This creates a Marangoni drying pocket adjacent to the meniscus 39. Marangoni drying promotes good drying of the lower surface 25 of the substrate W. IPA (or other alcohol solvents) reduces the surface tension of the meniscus 39. In one embodiment, the solvent used is easy to evaporate.

[0084]

[0097] FIG. 16 schematically shows a substrate W on a substrate support 20 according to an alternative embodiment of the present invention. FIG. 19 schematically shows another view of the substrate W on the substrate support 20. FIG. 19 is a cross-sectional view without passing through the bar 22 at all. Many features of the substrate support 20 are the same as the substrate support 20 described above. The following description focuses on the different features of the substrate support 20 shown in FIGS. 16 and 19.

[0085]

[0098] As shown in FIG. 19, in one embodiment, the substrate support 20 includes a vapor supply channel 191. The vapor supply channel 191 is for supplying the vapor of the conductive liquid 27 to a certain region of the lower surface 25 of the substrate W. In one embodiment, the vapor supply channel 191 is configured to supply moist air containing the vapor of the conductive liquid 27. When the vapor is supplied to the gap 26, a moisture layer of the conductive liquid 27 is formed on the lower surface 25 of the substrate W as shown in FIGS. 16 and 19. The conductive liquid 27 covers a certain region of the lower surface 25 of the substrate W.

[0086]

[0099] The region of the lower surface 25 of the substrate W on which the water layer of the conductive liquid 27 is applied is adjacent to at least one tip portion 24 of the bar 22. Thereby, electric charges can pass between the region of the lower surface 25 of the substrate W (on which the water layer is applied) and the bar 22.

[0087]

[0100] FIG. 20 schematically shows the passage of electric charges between one of the lower surface 25 of the substrate W and the bar 22. FIG. 20 shows a plurality of positive charges on the lower surface 25 of the substrate W. Specifically, FIG. 20 shows the positive charges in the portion of the lower surface 25 of the substrate W that is in physical contact with the tip portion 24 of the bar 22. FIG. 20 further shows the positive charges in another portion of the lower surface 25 that is not in direct contact with the tip portion 24 of the bar 22. In one embodiment, at least a portion of the substrate support 20 is electrically grounded or electrically biased. For example, as described above, the base surface 23 of the substrate 20 is electrically grounded or electrically biased. Additionally or alternatively, the tip portion 24 of the bar 22 is electrically grounded or electrically biased.

[0088]

[0101] The charges in the portion of the lower surface 25 of the substrate W that is in physical contact with the bar 22 may pass between the lower surface 25 and the bar 22. By providing a water layer of the conductive liquid 27 in the region of the lower surface 25 adjacent to the tip portion 24 of the bar 22, other positive charges can pass between the lower surface 25 and the bar 22. In one embodiment, the tip portion 24 has a controlled potential so as to be able to manipulate the charge distribution on the lower surface 25 of the substrate W.

[0089]

[0102] In one embodiment, the substrate support 20 is used to support the substrate W before it is moved onto the substrate table WT on which the substrate W is used during the exposure process. By supplying the vapor of the conductive liquid 27 to a region of the lower surface 25 adjacent to at least one tip 24 of the bar 22, the charge can be removed from the substrate W before the substrate W is placed on the substrate table WT. In one embodiment, the bar 22 is conductive. The tip 24 of the bar 22 of the substrate support 20 may oxidize. This may help reduce the amount of oxidation that occurs when the substrate W is on the substrate table WT used in the exposure process.

[0090]

[0103] In one embodiment, the substrate table WT includes a plurality of bars having tips in a plane for supporting the lower surface 25 of the substrate W during the exposure process. In one embodiment, the pattern of the bars 22 of the substrate support 20 is the same as the pattern of the bars on the substrate table WT. In one embodiment, the position of the center of the bars 22 of the substrate support 20 in plan view is the same as the position of the center of the bars of the substrate table WT. As shown in FIG. 20, the charge can be removed from each portion of the lower surface 25 of the substrate W that contacts the tip 24 of the bar 22. By making the bar pattern the same for the substrate support 20 and the substrate table WT, the charge is removed from the substrate W, specifically from the portion that was most likely to cause the oxidation problem of the substrate table WT. Some embodiments of the present invention are expected to reduce the deterioration of the substrate table WT.

[0091]

[0104] It is not essential that the pattern of the bars 22 of the substrate support 20 be the same as the pattern of the bars of the substrate table WT. The charge can be removed from the section of the lower surface 25 that will contact the bars of the substrate table WT through the water layer of the conductive liquid 27.

[0092]

[0105] As shown in FIGS. 16, 19, and 20, in one embodiment, a moisture layer is provided around the bar 22 of the substrate support 20. The moisture layer of the conductive liquid 27 enables the removal of charge from a section of the lower surface 25 that is not in direct contact with the tip 24 of the bar 22.

[0093]

[0106] It is not essential to provide the moisture layer on the lower surface 25 of the lower substrate W. Charge can be removed from the portion of the lower surface 25 that is in direct contact with the bar 22 of the substrate support 20 without requiring a moisture layer for the conductive liquid 27. The conductive liquid 27 enables the removal of charge from a larger area of the substrate W.

[0094]

[0107] The conductive liquid 27 is configured to mobilize the charge fixed at the lower surface 25 in another way. As shown in FIG. 16, in one embodiment, the substrate support 20 includes a coating 162 at the tip 24 of the bar 22. The coating 162 has a fairly low electrical resistance. In one embodiment, the coating is electrically dissipative. For example, in one embodiment, the coating 162 has a resistance of at most 100 MΩ, optionally at most 10 MΩ, and optionally at most 1 MΩ. In one embodiment, an electrical resistance of at least 10 kΩ. In one embodiment, the coating 162 includes diamond-like carbon (DLC), silicon carbide (e.g., silicon infiltrated silicon carbide, SiSiC), and / or chromium nitride.

[0095]

[0108] As shown in FIG. 16, in certain embodiments, the bar 22 comprises a further coating layer 163. The further coating layer 163 is disposed between the coating 162 and the bulk of the bar 22. The further coating layer 163 may comprise a material susceptible to oxidation, such as carbon. The further coating layer 163 may comprise a catalyst configured to chemically reduce the vapor at the lower surface 25. This may serve to generate cations to at least partially neutralize the charge on the substrate W. FIG. 17 shows an alternative embodiment of the substrate support 20. As shown in FIG. 17, in certain embodiments, the further coating layer 163 is not provided.

[0096]

[0109] FIG. 18 shows an alternative embodiment of the substrate support 20. In the embodiment shown in FIG. 18, the bar 22 of the substrate support 20 has a larger diameter compared to, for example, the bar 22 shown in the substrate support of FIG. 16 or FIG. 17. In certain embodiments, the bar 22 of the substrate support 20 has a larger diameter than the bar of the substrate table WT. By having the bar 22 with a larger diameter, the possibility of charge remaining in certain regions of the lower surface 25 that would come into contact with the bar of the substrate table WT can be reduced. When the substrate W is placed on the substrate table WT, misalignment or inconsistency may occur. The larger diameter bar 22 shown in FIG. 18 removes charge from a larger local area of the lower surface 25 of the substrate W. This allows for errors when the substrate W is placed on the substrate table WT. The bar of the substrate table WT is contained within the area of the lower surface 25 whose charge has been removed by the bar 22 of the substrate support 20.

[0097]

[0110] Optionally, a water layer of the conductive liquid 27 may be provided around the bar 22 so as to remove charge from a larger area of the lower surface 25 of the substrate W. The charge is removed from the lower surface 25 through the conductive tip 24 of the bar 22.

[0098]

[0111] For example, as shown in FIG. 16, in one embodiment, the lower surface 25 of the substrate W includes an insulating layer 161. In one embodiment, the insulating layer 161 includes SiO 2 and. Other possible materials for the insulating layer are known to those skilled in the art.

[0099]

[0112] As shown in FIG. 19, in one embodiment, the substrate support 20 includes a gas supply channel 31. In one embodiment, the gas supply channel 31 and the vapor supply channel 191 share a common opening 32 on the base surface 23 of the substrate support 20. In one embodiment, a vapor valve 192 is provided to control the supply of the vapor of the conductive liquid 27 through the opening 32.

[0100]

[0113] In an alternative embodiment, the vapor supply channel 191 and the gas supply channel 31 may be a single channel. The gas supply channel 31 may function as the vapor supply channel 191 by supplying the vapor of the conductive liquid 27 to the gap 26.

[0101]

[0114] In one embodiment, the gas supply channel 31 is configured to supply gas to the gap 26 to remove the moisture layer of the conductive liquid 27 from the lower surface 25 of the substrate W.

[0102]

[0115] In one embodiment, the charge manipulation and the drying of the substrate W are performed while the substrate W is thermally regulated on the substrate support 20. Some embodiments of the present invention are expected to reduce the deterioration of the substrate table WT without substantially reducing the throughput. In an alternative embodiment, the thermal regulation is performed after the charge removal and / or drying.

[0103]

[0116] In one embodiment, the conductive liquid 27 is water saturated with carbon dioxide. In an alternative embodiment, the conductive liquid 27 is IPA. The conductive liquid 27, such as IPA, can be thermally conditioned before contacting the substrate W. The conductive liquid 27 can be used to thermally condition the substrate W. The conductive liquid 27 is configured to improve heat transfer between the substrate support 20 and the substrate W. For example, IPA can improve the heat transfer coefficient between the substrate W and the substrate support 20.

[0104]

[0117] In the embodiment shown in the figure, the supply channels 28, 31 are provided at an intermediate radius, and the extraction channels 29, 30 are provided radially inward and radially outward. However, other configurations are also possible. In one embodiment, the supply channels 28, 31 and the extraction channels 29, 30 are provided to promote the radial flow of the lower surface 25 of the substrate W. The flow rate and pressure can be controlled.

[0105]

[0118] In one embodiment, the lower surface 25 of the substrate W is coated. The coating is configured to reduce the surface free energy at the lower surface 25 of the substrate W. In one embodiment, the coating is applied after the lower surface 25 of the substrate W is dried. In one embodiment, the bubbler is configured to evaporate the liquid coating material into a gaseous carrier medium. In an alternative embodiment, a controlled evaporation mixture can be used to evaporate the liquid coating material into a gaseous carrier medium.

[0106]

[0119] The embodiments in which the substrate support 20 is included in the accommodation unit have been described above. In an alternative embodiment, the substrate support 20 is arranged in another unit or another position within the lithographic apparatus 100. For example, the substrate support 20 may be included in a temperature stabilization unit configured to stabilize the temperature of the substrate W. The temperature stabilization unit may be thermally conditioned, for example, by a flow of a thermally conditioning liquid and / or a gas shower. In one embodiment, the substrate support 20 is arranged at a threshold over which the substrate W translates as the substrate W moves within the lithographic apparatus 100.

[0107]

[0120] The substrate support 20 may be arranged to translate relative to the substrate support 20 before the substrate W is placed on the substrate table WT.

[0108]

[0121] In certain embodiments, the substrate support 20 is outside the lithographic apparatus 100. For example, the substrate support 20 may be in a position through which the substrate W translates before entering the lithographic apparatus 100, or the substrate support 20 may be provided in a separate stand-alone unit (accommodation unit or temperature stabilization unit) separate from the lithographic apparatus 100.

[0109]

[0122] In certain embodiments, a device is manufactured by a device manufacturing method that includes using the lithographic apparatus 100 described above. The lithographic apparatus 100 transfers a pattern from the patterning device MA to the substrate W. In certain embodiments, the device manufacturing method includes methods of manipulating the charge distribution and / or methods of drying the substrate W as described above.

[0110]

[0123] Although this document particularly refers to the use of a lithographic apparatus in the manufacture of ICs, it should be understood that the lithographic apparatus described herein has other applications. For example, this includes the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads, etc. In light of such alternative applications, it will be recognized by those skilled in the art that when the terms "wafer" or "die" are used herein, they may be regarded as synonymous with the more general terms "substrate" or "target portion", respectively. The substrates described herein can be processed, before or after exposure, by, for example, a track (a tool that typically applies a layer of resist to the substrate and develops the exposed resist), a metrology tool and / or an inspection tool. Appropriately, the disclosure herein can be applied to the above and other substrate processing tools. Further, the substrate can be processed multiple times, for example, to produce a multilayer IC, and thus the term "substrate" as used herein can also refer to a substrate that already includes multiple processed layers.

[0111]

[0124] As used herein, the terms "radiation" and "beam" encompass not only particle beams such as ion beams or electron beams, but also any type of electromagnetic radiation including ultraviolet (UV) radiation (e.g., having a wavelength of 365 nm, 248 nm, 193 nm, 157 nm or 126 nm, or around these wavelengths) and extreme ultraviolet (EUV) radiation (e.g., having a wavelength in the range of 5 nm to 20 nm).

[0112]

[0125] Although specific embodiments of the invention have been described above, it will be understood that the invention can be practiced in a different manner than described. The above description is illustrative and not restrictive. Thus, it will be apparent to those skilled in the art that the invention as described can be modified without departing from the scope of the claims.

Claims

1. A substrate support for supporting a substrate before moving the substrate on a substrate table for an exposure process, wherein the substrate support, a plurality of bars protruding from a base surface of the substrate support and having tip portions in a plane for supporting a lower surface of the substrate with a gap provided between the base surface of the substrate support and the lower surface of the substrate; a liquid supply channel for allowing charge to pass between the substrate support and the substrate by supplying a conductive liquid only to the gap to fill the gap between the base surface of the substrate support and the lower surface of the substrate; the substrate support having a potential controlled so as to be able to manipulate a charge distribution on the lower surface of the substrate.

2. A substrate support for supporting a substrate before moving the substrate on a substrate table for an exposure process, wherein the substrate support, a plurality of bars protruding from a base surface of the substrate support and having tip portions in a plane for supporting a lower surface of the substrate with a gap provided between the base surface of the substrate support and the lower surface of the substrate; a vapor supply channel for allowing charge to pass between a region of the lower surface of the substrate adjacent to the tip portion of at least one of the bars and the bar by supplying a vapor of a conductive liquid only to the region of the lower surface of the substrate; the tip portion having a potential controlled so as to be able to manipulate a charge distribution on the lower surface of the substrate.

3. Further comprising a gas supply channel for supplying gas to the gap to displace the conductive liquid from the gap, and / or the conductive liquid or the vapor of the conductive liquid is supplied such that a moisture layer of the conductive liquid is formed on the lower surface of the substrate, the substrate support according to claim 1 or 2.

4. The substrate support according to any one of claims 1 to 3, wherein at least a part of the substrate support is electrically grounded or electrically biased.

5. Comprising one or more extraction channels for extracting at least one of gas and liquid from the gap, Optionally, the base surface has a shape in which the gap narrows towards the one or more extraction channels, the substrate support according to any one of claims 1 to 4.

6. The conductive liquid is CO ２ contains at least one selected from the group consisting of saturated water and isopropyl alcohol, and / or The substrate support according to any one of claims 1 to 5, wherein the substrate support utilizes a mechanical clamping technique for holding the substrate.

7. A lithographic apparatus comprising a substrate support according to any one of claims 1 to 6, wherein the substrate support is stationary.

8. A method of manipulating the charge distribution on the lower surface of a substrate before moving the substrate onto a substrate table for an exposure process, the method comprising: supporting the lower surface of the substrate on a plurality of bars protruding from a base surface of a substrate support and having a tip portion in a plane, with a gap provided between the base surface of the substrate support and the lower surface of the substrate; and making it possible for charge to pass between the substrate support and the substrate by supplying a conductive liquid only to the gap in order to fill the gap between the base surface of the substrate support and the lower surface of the substrate, wherein the substrate support has a potential controlled such that the charge distribution on the lower surface of the substrate is manipulated.

9. The method of claim 8, comprising supplying a gas to the gap in order to move the conductive liquid radially within the gap, such that when the conductive liquid moves and contacts a charged portion on the lower surface of the substrate, charge passes between the charged portion and the base surface of the substrate support.

10. The method according to claim 8 or 9, comprising supplying a gas to the gap in order to displace the conductive liquid from the gap, the gas being a vapor of an organic liquid soluble in the conductive liquid and including a vapor that dissolves in the meniscus while the meniscus of the conductive liquid traverses the lower surface of the substrate, thereby promoting drying of the lower surface.

11. A method of manipulating the charge distribution on the lower surface of a substrate before moving the substrate onto a substrate table for an exposure process, the method comprising: supporting the lower surface of the substrate on a plurality of bars protruding from a base surface of a substrate support and having a tip portion in a plane, with a gap provided between the base surface of the substrate support and the lower surface of the substrate; and making it possible for charge to pass between a region of the lower surface of the substrate adjacent to the tip portion of at least one of the bars and the bar by supplying a vapor of a conductive liquid only to the region. A method in which the tip has a potential controlled such that the charge distribution on the lower surface of the substrate is manipulated. **Claim 12** A method according to any one of claims 8 to 11, carried out while the substrate is thermally conditioned for an exposure process. **Claim 13** A method of providing a substrate to be exposed by a patterned radiation beam, the method comprising: loading the substrate into a lithographic apparatus; supporting the substrate on a substrate support according to any one of claims 1 to 6; drying the lower surface of the substrate; and moving the dried substrate to a substrate table where the upper surface of the substrate, opposite the lower surface, is exposed to the patterned radiation beam. **Claim 14** The method of claim 13, wherein drying is by supplying a gas flow to a gap between the lower surface of the substrate and the base surface of the substrate support from the substrate support. **Claim 15** The method of claim 14, wherein the gas flow provides a gas film for supporting the substrate above the substrate support without the substrate and the substrate support contacting each other.

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