System for changing shape of substrate

Abstract

Disclosed herein is a substrate support apparatus configured to support a substrate, the substrate support apparatus comprising: a substrate support having a substantially planar support surface for the substrate; and a substrate forming system comprising one or more substrate forming devices; wherein each substrate forming device is movable relative to the substrate support; and wherein when the substrate is disposed on the support surface, each substrate shaping device is arranged to apply an electrostatic force to a periphery of the substrate.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to EP application 23156107.7 filed on February 10, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to a technique for changing the shape of a substrate. Electrostatic force may be applied to the periphery of a substrate W to at least partially reduce deformation of the substrate's shape. Background Art

[0004] A lithographic apparatus is a machine configured 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 from a patterning device (e.g., a mask or reticle) onto a layer of radiation-sensitive material (resist) disposed on a substrate.

[0005] As semiconductor manufacturing processes continue to advance, the size of circuit elements continues to decrease, while the number of functional elements (such as transistors) per device has been steadily increasing for decades, a trend often referred to as "Moore's Law." To keep up with Moore's Law, the semiconductor industry is pursuing technologies that can create smaller and smaller features.

[0006] To project a pattern onto a substrate, a lithographic apparatus can use electromagnetic radiation. The wavelength of this radiation determines the minimum size of features that can be formed on the substrate. Typical wavelengths currently used are 365 nm (i-line), 248 nm, 193 nm, and 13.5 nm. Compared to lithographic apparatuses that use radiation with a wavelength of, for example, 193 nm, lithographic apparatuses that use extreme ultraviolet (EUV) radiation with a wavelength in the range of 4-20 nm (e.g., 6.7 nm or 13.5 nm) can be used to form smaller features on a substrate.

[0007] In conventional lithographic equipment, the substrate to be exposed can be supported by a substrate support (i.e., an object that directly supports the substrate), which in turn is supported by a substrate table (a mirror block or stage, i.e., an object that supports the substrate support and provides an upper surface around the substrate support, such as a table). The substrate support is typically a flat, rigid disk corresponding to the size and shape of the substrate (although it can have different sizes or shapes). It has a series of protrusions, called bumps or pimples, protruding from at least one side. The substrate support can have a series of protrusions on two opposing sides. In this case, when the substrate support is placed on the substrate table, the main body of the substrate support is held a small distance above the substrate table, with the ends of the bumps on one side of the substrate support resting on the surface of the substrate table. Similarly, when the substrate is placed on top of the bumps on the opposite side of the substrate support, the substrate is spaced apart from the main body of the substrate support. The purpose of this is to help prevent particles that may be present on the substrate table or substrate support (i.e., contaminants such as dust particles) from distorting the substrate support or substrate. Since the total surface area of ​​the bumps is only a small fraction of the total area of ​​the substrate or substrate support, any particles are likely to be located between the bumps and their presence will have no effect. Typically, the substrate support and substrate are housed within a recess in the substrate table such that the upper surface of the substrate is substantially coplanar with the upper surface of the substrate table.

[0008] Since the substrate experiences high accelerations when used in high-throughput lithographic equipment, it is not enough to simply allow the substrate to rest on the bumps of the substrate support. It is clamped in place. Two methods are known for clamping the substrate in place - vacuum clamping and electrostatic clamping. In vacuum clamping, the space between the substrate support and the substrate and (optionally) the space between the substrate table and the substrate support is partially evacuated so that the substrate is held in place by a higher gas or liquid pressure above it. However, in cases where the beam path and / or the environment near the substrate or substrate support is maintained at low pressure or very low pressure, such as in extreme ultraviolet (EUV) radiation lithography, vacuum clamping may not be used. In this case, it may not be possible to generate a sufficiently large pressure difference on the substrate (or substrate support) to clamp it. Therefore, electrostatic clamping can be used. In electrostatic clamping, a potential difference is established between the substrate or an electrode coated on its lower surface and an electrode arranged on or in the substrate table and / or substrate support. The two electrodes behave like a large capacitor and a considerable clamping force can be generated using a reasonable potential difference. The electrostatic arrangement may be such that a pair of electrodes, one on the substrate table and one on the substrate, clamps the entire stack of substrate table, substrate support and substrate together. In known arrangements, one or more electrodes may be provided on or in the substrate support so that the substrate support is clamped to the substrate table and the substrate is separately clamped to the substrate support.

[0009] There is a need for improvements in substrate supports including one or more electrostatic clamps for clamping the substrate support to a substrate table and / or clamping a substrate to the substrate support. More generally, there is a need for improvements in object holders, such as patterned device holders, including one or more electrostatic clamps for holding the object holder on a table and / or holding an object on the object holder. Summary of the Invention

[0010] According to a first aspect of the present invention, there is provided a substrate support apparatus configured to support a substrate, the substrate support apparatus comprising: a substrate support having a substantially planar support surface for the substrate; and a substrate forming system comprising one or more substrate forming devices; wherein each substrate forming device is movable relative to the substrate support; and wherein each substrate forming device is arranged to apply an electrostatic force to a periphery of the substrate when the substrate is disposed on the support surface.

[0011] According to a second aspect of the present invention, there is provided a lithographic apparatus comprising a substrate support device according to the first aspect.

[0012] According to a third aspect of the present invention, there is provided a method of changing the shape of a substrate, the method comprising: loading a substrate onto a substrate support of the substrate support apparatus according to the first aspect; and applying an electrostatic force to a periphery of the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0014] Figure 1 schematically depicts an EUV lithography system including a lithographic apparatus and a radiation source;

[0015] Figure 2 is a cross-sectional view of an object holder according to an embodiment of the present invention;

[0016] Figure 3 A DUV lithography apparatus is schematically depicted;

[0017] Figure 4 A substrate support is schematically depicted in cross-section;

[0018] Figure 5 schematically depicts a substrate support apparatus for an EUV system according to a first embodiment;

[0019] Figure 6 schematically illustrates a substrate support device for a DUV system according to a second embodiment; and

[0020] Figure 7 A portion of a seal according to a second embodiment is schematically shown.

[0021] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and may be described in detail herein. The drawings may not be drawn to scale. However, it should be understood that the drawings and detailed description thereof are not intended to limit the invention to the particular forms disclosed, but rather are intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. DETAILED DESCRIPTION

[0022] Figure 1 A lithographic system is shown comprising a radiation source SO and a lithographic apparatus LA. The radiation source SO is configured to generate an EUV radiation beam B and provide the EUV radiation beam B to the lithographic apparatus LA. The lithographic apparatus LA comprises an illumination system IL, a support structure MT configured to support a patterning device MA (e.g., a mask or reticle), a projection system PS, and a substrate table WT configured to support a substrate W.

[0023] The illumination system IL is configured to condition the EUV radiation beam B before it is incident on the patterning device MA. To this end, the illumination system IL may include a faceted field mirror device 10 and a faceted pupil mirror device 11. The faceted field mirror device 10 and the faceted pupil mirror device 11 together provide a desired cross-sectional shape and a desired intensity distribution for the EUV radiation beam B. In addition to or instead of the faceted field mirror device 10 and the faceted pupil mirror device 11, the illumination system IL may include other mirrors or devices.

[0024] After being so conditioned, the EUV radiation beam B interacts with the patterned device MA. As a result of this interaction, a patterned EUV radiation beam B' is generated. The projection system PS is configured to project the patterned EUV radiation beam B' onto the substrate W. To this end, the projection system PS may include a plurality of mirrors 13, 14 configured to project the patterned EUV radiation beam B' onto the substrate W held by the substrate table WT. The projection system PS may apply a reduction factor to the patterned EUV radiation beam B' so as to form an image having features that are smaller than corresponding features on the patterned device MA. For example, a reduction factor of 4 or 8 may be applied. Although the projection system PS is Figure 1 1. Although shown in FIG. 1 with only two mirrors 13, 14, the projection system PS may comprise a different number of mirrors (eg six or eight mirrors).

[0025] The substrate W may comprise a pre-formed pattern. In this case, the lithographic apparatus LA aligns the image formed by the patterned EUV radiation beam B′ with the pattern previously formed on the substrate W.

[0026] A relative vacuum, ie, a small amount of gas (eg, hydrogen) at a pressure well below atmospheric pressure, may be provided in radiation source SO, illumination system IL, and / or projection system PS.

[0027] The radiation source SO may be a laser produced plasma (LPP) source, a discharge produced plasma (DPP) source, a free electron laser (FEL), or any other radiation source capable of generating EUV radiation.

[0028] Figure 2 2 is a cross-sectional view of the substrate support 20. The substrate support 20 is configured to support a substrate W.

[0029] The substrate table WT comprises a substrate support 20 and a substrate stage (not shown). The substrate stage comprises a recess into which the substrate support 20 is held. The substrate support 20 is configured to hold a substrate W relative to the substrate stage of the substrate table WT.

[0030] like Figure 2 As shown, the substrate support 20 includes a support body 21. The support body 21 is a plate-shaped disk. Figure 2 As shown, the support body 21 includes a plurality of bumps 22. The bumps 22 are protrusions protruding from the surface of the support body 21. Figure 2 As shown, the bump 22 has a distal end 23. The support body 21 is configured such that the distal end 23 defines a support plane 24 for supporting the substrate W. The underside of the substrate W contacts the distal end 23 of the bump 22. The position of the underside of the substrate W corresponds to the support plane 24. The bump 22 is arranged such that the substrate W lies substantially flat on the substrate support 20.

[0031] Bump 22 Figure 2 In a practical embodiment, there may be hundreds, thousands, or tens of thousands of bumps 22 distributed on a substrate support 20 having a diameter of 200 mm, 300 mm, or 450 mm. The tip (i.e., distal end 23) of the bump 22 has a relatively small area, for example, less than 1 mm. 2 , so that the total area of ​​all bumps 22 on one side of the substrate support 20 is less than about 10% of the total surface area of ​​the substrate support 20. Due to the arrangement of the bumps 22, any particles that may be located on the surface of the substrate W, substrate support 20 or substrate table WT are likely to fall between the bumps 22 and therefore not cause deformation of the substrate W or substrate support 20. The bump arrangement, which may form a pattern, may be regular or may be varied as required to provide an appropriate force distribution on the substrate W and substrate table WT. The bumps 22 may have any planar shape, but are typically circular. The bumps 22 may have the same shape and size throughout their height, but are typically conical. The bumps 22 may protrude above the remaining object-facing surface of the substrate support 20 (i.e., the top surface of the electrostatic sheet 25) by a distance of about 1 μm to about 5 mm, desirably about 5 μm to 250 μm, desirably about 10 μm. Therefore, the vertical distance between the distal end 23 of the bump 22 and the top surface of the electrostatic sheet 25 is about 1 μm to about 5 mm, preferably about 5 μm to 250 μm, and preferably about 10 μm. The thickness of the support body 21 of the substrate support member 20 can be in the range of about 1 mm to about 50 mm, preferably about 5 mm to 20 mm, and typically 10 mm.

[0032] The support body 21 can be made of a rigid material. Desirably, the material has a high thermal conductivity and a coefficient of thermal expansion close to that of the object being held. Desirably, the material is electrically conductive. Desirably, the material has a high hardness. Suitable materials include SiC (silicon carbide), SiSiC (siliconized silicon carbide), Si3N4 (silicon nitrite), quartz, and / or various other ceramics and glass ceramics, such as Zerodur.TM Glass ceramics. The support body 21 can be made by selectively removing material from a solid disk of the relevant material to leave a protruding bump 22. Suitable techniques for removing material include electrical discharge machining (EDM), etching, machining and / or laser ablation. The support body 21 can also be made by growing the bump 22 through a mask. The bump 22 can be made of the same material as the substrate and can be grown by a physical vapor deposition process or sputtering. The support body 21 may include one or more internal channels (not shown in the figure). The support body 21 may include a plurality of layers bonded together. These layers may be formed of different materials. As just one example, in the support body 21, a SiSiC layer, a glass layer, and another layer of SiSiC may be included in sequence. Combinations of other layers are also possible.

[0033] like Figure 2 As shown, the substrate support 20 may include one or more electrodes 26 for electrostatic clamping. A potential difference may be generated to provide an electrostatic clamping force between the substrate W and the substrate support 20 and / or between the substrate support 20 and the substrate table of the substrate table WT. The electrodes 26 may be enclosed between dielectric layers 27, 28 (also referred to as electrical isolation layers). The potential difference generated may be on the order of 10 to 5000 volts. An arrangement for locally controlling the temperature of a substrate using one or more heaters and temperature sensors is described in U.S. Publication No. 2011-0222033, the entire contents of which are incorporated herein by reference, and the teachings therein may be applied to the technology herein.

[0034] like Figure 2 As shown, the substrate support 20 may include an electrostatic sheet 25. The electrostatic sheet 25 includes one or more electrodes 26. For the electrodes 26, the two halves of the continuous metal film (but isolated from the distal end 23 of the bump 22) may be separated from each other by a spacing distance and deposited to form the positive and negative elements of the electrostatic chuck. The spacing distance is not particularly limited. The spacing distance may be at least about 20 μm, optionally at least about 50 μm, optionally at least about 100 μm, optionally at least about 200 μm, optionally at least about 500 μm. The spacing distance may be at most about 2 mm, optionally at most about 1 mm, optionally at most about 500 μm. The spacing distance may be about 500 μm. Thus, there may be two electrodes 26. However, the number of electrodes 26 in the electrostatic sheet 25 is not particularly limited and may be one or three or more. The metal wire of the electrode 26 may have a layer thickness greater than about 20 nm, desirably greater than about 40 nm. The metal lines desirably have a layer thickness less than or equal to about 1 μm, desirably less than about 500 nm, desirably less than about 200 nm.

[0035] The electrodes 26 of the upper electrostatic plate 25 may be configured to electrostatically clamp the substrate W to the substrate support 20. The electrodes 26 of the lower electrostatic plate 25 may be configured to electrostatically clamp the substrate support 20 to the remainder, eg a substrate table of the substrate table WT.

[0036] The material of the support body 21 and the bump 22 can be conductive. For example, the material of the bump 22 can be SiSiC. However, the material of the support body 21 and the bump 22 is not necessarily conductive. A ground layer can be provided, which electrically connects the distal ends 23 of two or more bumps 22 (optionally, all bumps 22) to the ground or a common potential. The ground layer can be formed by depositing a relatively thick layer of conductive material. There is no particular limitation on the conductive material. The conductive material can be Cr or CrN. The deposited layer can then be patterned to form a ground layer. The pattern can include a series of metal lines connecting the distal ends 23 of the bumps 22 together. This pattern is sometimes called a "Manhattan" pattern. In an alternative arrangement, the deposited layer is not patterned. The ground layer or another layer can be arranged to cover the surface of the support body 21 and / or the bump 22. The ground layer or another layer can help smooth the surface, making it easier to clean the surface.

[0037] like Figure 2 As shown, the electrostatic sheet 25 may include an electrode 26 sandwiched between dielectric layers 27, 28. Figure 2 As shown, the bumps 22 and the electrostatic sheet 25 may be provided on both main surfaces of the substrate support 20. In an alternative arrangement, the bumps 22 and the electrostatic sheet 25 are provided on only one of the two main surfaces of the substrate support 20. Figure 2 As shown, the electrostatic sheet 25 may be interposed between the bumps 22. For example, Figure 2 As shown, holes 34 are provided in the electrostatic sheet 25. The holes 34 are arranged so that their positions correspond to the bumps 22 of the support body 21. The bumps 22 protrude through the corresponding holes 34 of the electrostatic sheet 25, so that the electrodes 26 sandwiched between the dielectric layers 27 and 28 are provided in the area between the bumps 22.

[0038] like Figure 2 As shown, substrate support 20 may include bonding material 29. Bonding material 29 may have a thickness of at least 100 nm, for example, about 50 μm. Bonding material 29 secures the position of electrostatic plate 25 relative to support body 21. Bonding material 29 aligns holes 34 in electrostatic plate 25 with bumps 22. Bumps 22 may be positioned at the center of corresponding holes 34 in electrostatic plate 25.

[0039] like Figure 2As shown, bonding material 29 can be formed in discrete portions that are not connected to each other. There can be some variation in the thickness of different portions of bonding material 29. Individual portions of bonding material 29 can have substantially the same thickness as each other.

[0040] As described above, the substrate table WT includes a substrate support 20 and a substrate work table. The substrate work table includes a recess into which the substrate support 20 is held. The substrate support 20 and the substrate work table may be referred to as a substrate table WT.

[0041] A substrate support 20 for an EUV lithography system is described above. Next, a configuration of a substrate in a DUV system is described.

[0042] Figure 3 A lithographic apparatus is schematically depicted. The lithographic apparatus comprises an illumination system (also called illuminator) IL configured to condition a radiation beam B (e.g., UV radiation or DUV radiation), a support structure (e.g., mask table) MT configured to support a patterning device (e.g., mask) MA and connected to a first positioner PM configured to precisely position the patterning device MA according to certain parameters, a substrate table WT, optionally comprising a substrate support, configured to hold a substrate (e.g., a resist-coated wafer) W and connected to a second positioner PW configured to precisely position the substrate table WT according to certain parameters, and a projection system PS (e.g., a refractive projection lens system) configured to project a pattern imparted to the radiation beam B by the patterning device MA onto a target portion C (e.g., comprising one or more dies) of the substrate W.

[0043] 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 it has a desired spatial and angular intensity distribution in its cross-section at the plane of the patterned device MA.

[0044] The term "projection system" PS as used herein should be interpreted broadly 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 an immersion liquid or the use of a vacuum. Any use of the term "projection lens" herein may be considered as a synonym for the more general term "projection system" PS.

[0045] The lithographic apparatus is of a type in which at least a portion of the substrate W may be covered by an immersion liquid (e.g. water) having a relatively high refractive index to fill an immersion space 11 between the projection system PS and the substrate W, which is also referred to as immersion lithography. More information on immersion technology is given in US 6,952,253, which is incorporated herein by reference.

[0046] The lithographic apparatus may be of a type having two or more substrate tables WT (also called "dual stage"). In such a "multi-stage" machine, the substrate tables WT may be used in parallel, and / or preparatory steps for subsequent exposure of a substrate W may be performed on a substrate W on one substrate table WT, while another substrate W on another substrate table WT is being used to expose a pattern on yet another substrate W.

[0047] In addition to the substrate table WT, the lithographic apparatus may further comprise a measurement stage (not shown in the figure). The measurement stage is arranged to hold sensors and / or cleaning devices. The sensors may be arranged to measure properties of the projection system PS or properties of the radiation beam B. The measurement stage may accommodate a plurality of sensors. The cleaning devices 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 measurement stage may be moved under the projection system PS when the substrate support WT is away from the projection system PS.

[0048] In operation, a radiation beam B is incident on a patterning device MA (e.g., a mask) held on the support structure MT and is patterned by a pattern (design layout) present on the patterning device MA. After traversing the patterning device MA, the radiation beam B passes through a projection system PS, which focuses the beam onto a target portion C of the substrate W. With the aid of a second positioner PW and a position measurement system IF, the substrate table WT can be precisely moved, for example, to position different target portions C in the path of the radiation beam B at focused and aligned positions. Similarly, a first positioner PM and possibly another position sensor ( Figure 1 The mask alignment marks M1, M2 and substrate alignment marks P1, P2 can be used to precisely position the patterned device MA relative to the path of the radiation beam B. The patterned device MA and substrate W can be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2. Although the substrate alignment marks P1, P2 are shown as occupying dedicated target portions, they can be located in the spaces between target portions. When the substrate alignment marks P1, P2 are located between target portions C, they are referred to as scribe lane alignment marks.

[0049] To illustrate this specification, a Cartesian coordinate system is used. A Cartesian coordinate system has three axes, namely the x-axis, the y-axis, and the z-axis. Each of these three axes is orthogonal to the other two axes. A rotation around the x-axis is called an Rx rotation. A rotation around the y-axis is called an Ry rotation. A 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 the vertical direction. The Cartesian coordinate system does not limit this specification, but is merely used for illustration. Conversely, another coordinate system (such as a cylindrical coordinate system) can be used to illustrate this specification. The orientation of the Cartesian coordinate system can be different, for example, so that the z-axis has a component along the horizontal plane.

[0050] Immersion technology has been introduced into lithography systems to improve the resolution of smaller features. In an immersion lithography apparatus, a layer of immersion liquid having a relatively high refractive index is placed in the immersion space between the apparatus's projection system PS (through which a patterned beam is projected toward the substrate W) and the substrate W. The immersion liquid covers at least the portion of the substrate W beneath the final element of the projection system PS. Thus, at least the exposed portion of the substrate W is immersed in the immersion liquid.

[0051] In commercial immersion lithography, the immersion liquid is water. Typically, the water is high-purity distilled water, such as the ultrapure water (UPW) commonly used in semiconductor manufacturing plants. In immersion systems, the UPW is typically purified, and it may undergo additional processing steps before being supplied to the immersion space as the immersion liquid. In addition to water, other liquids with a high refractive index can be used as immersion liquids, for example: hydrocarbons, such as fluorocarbons; and / or aqueous solutions. Furthermore, other fluids besides liquids are also contemplated for use in immersion lithography.

[0052] In this specification, reference will be made to local immersion in the description, wherein, in use, immersion liquid is confined in an immersion space between a final element and a surface facing the final element. The facing surface is the surface of the substrate W or a surface of a support table (or substrate table WT or substrate support) that is coplanar with the surface of the substrate W. (Note that, unless expressly stated otherwise, references to the surface of the substrate W in the following text are also in addition to or instead of the surface of the substrate table WT or substrate support; and vice versa). A fluid handling structure IH present between the projection system PS and the substrate table WT or substrate support serves to confine the immersion liquid in the immersion space. The immersion space filled with immersion liquid is smaller in plane than the top surface of the substrate W and remains substantially stationary relative to the projection system PS as the substrate W and substrate support move underneath.

[0053] Other immersion systems have been envisioned, such as unconfined immersion systems (so-called "all-wet" immersion systems) and bath immersion systems. In unconfined immersion systems, the immersion liquid covers an area larger than the surface beneath the final component. The liquid outside the immersion volume is present as a thin film. The liquid can cover the entire surface of the substrate W, even covering the substrate W and the substrate support WT coplanar with the substrate W. In bath systems, the substrate W is completely immersed in the immersion liquid bath.

[0054] The fluid handling structure IH is a structure for supplying immersion liquid to the immersion space, removing immersion liquid from the immersion space, and thereby confining the immersion liquid within the immersion space. It includes features that are part of the fluid supply system. The arrangement disclosed in PCT Patent Application Publication No. WO 99 / 49504 is an early fluid handling structure that includes conduits that supply or withdraw immersion liquid from the immersion space and whose operation depends on the relative movement of the worktable below the projection system PS. In more recent designs, the fluid handling structure extends along at least a portion of the boundary of the immersion space between the final element of the projection system PS and the substrate support WT or substrate W, thereby partially defining the immersion space.

[0055] The fluid handling structure 1H can have a variety of different functions. Each function can be derived from corresponding features that enable the fluid handling structure 1H to perform that function. The fluid handling structure 1H can be referred to by many different terms, each 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.

[0056] Immersion liquid can be used as immersion fluid. In this case, the fluid handling structure IH can be a liquid handling system. With reference to the above description, the features defined with respect to fluid mentioned in this paragraph can be understood to include features defined with respect to liquid.

[0057] The lithographic apparatus has a projection system PS. During exposure of a substrate W, the projection system PS projects a patterned radiation beam onto the substrate W. 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 IH between the projection system PS and the substrate W. The projection system PS has a lens element, the last one in the beam path, which is in contact with the immersion liquid. 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 is at least partially surrounded by the fluid handling structure IH. The fluid handling structure IH may confine the immersion liquid below the final element and above a facing surface.

[0058] like Figure 3As shown, the lithographic apparatus comprises a controller 500. The controller 500 is configured to control a substrate table WT.

[0059] Figure 4 There is shown a portion of a lithographic apparatus which is not in accordance with the invention but which may be used to demonstrate features of the invention. Figure 4 The arrangement shown and described below can be applied to the above and Figure 3 The lithographic apparatus shown. Figure 4 is a cross section through the substrate support 20 and the substrate W. Figure 3 The substrate table WT may comprise a substrate support 20 and a substrate table (not shown) configured to support the substrate support 20, or the substrate support 20 itself may be formed integrally with the substrate table WT as a single piece. In one embodiment, the substrate support 20 comprises one or more conditioning channels 61 of a thermal regulator 60, which will be described in more detail below. A gap 5 exists between the edge of the substrate W and the edge of the substrate support 20. When imaging the edge of the substrate W, or at other times, such as when the substrate W is first moved under the projection system PS (as described above), the immersion space filled with liquid (for example) by the fluid handling structure IH will at least partially pass through the gap 5 between the edge of the substrate W and the edge of the substrate support 20. This may cause liquid to enter the gap 5 from the immersion space.

[0060] The substrate W is held by a support body 21 (e.g., a bump or bump stage) that includes one or more bumps 41 (i.e., protrusions from the surface). The support body 21 is an example of an object holder. Another example of an object holder is a support structure MT. The underpressure applied between the substrate W and the substrate support 20 helps ensure that the substrate W is securely held in place. However, if immersion liquid enters between the substrate W and the support body 21, this can cause difficulties, particularly when unloading the substrate W.

[0061] In order to deal with the immersion liquid that enters the gap 5, at least one drain 10, 12 is provided at the edge of the substrate W to remove the immersion liquid that enters the gap 5. Figure 4 In FIG, two exhaust ports 10, 12 are shown, although there may be only one exhaust port or more than two exhaust ports. Each of the exhaust ports 10, 12 is annular so that the entire periphery of the substrate W is surrounded.

[0062] The primary function of the first drain port 10 (which is located radially outward of the edge of the substrate W / support body 21) is to help prevent bubbles from entering the immersion space of the fluid handling structure IH, where liquid is present. Such bubbles could adversely affect the imaging of the substrate W. The presence of the first drain port 10 is to help prevent gas in the gap 5 from escaping into the immersion space in the fluid handling structure IH. If gas does escape into the immersion space, this could cause bubbles to float within the immersion space. Such bubbles could cause imaging errors if they are in the path of the projection beam. The first drain port 10 is configured to remove gas from the gap 5 between the edge of the substrate W and the edge of a recess in the substrate support 20 in which the substrate W is placed. The edge of the recess in the substrate support 20 can be defined by a cover ring 101, which is optionally separate from the support body 21 of the substrate support 20. The cover ring 101 can be shaped as a ring in plan view and surrounds the outer edge of the substrate W. The first drain port 10 extracts primarily gas and only a small amount of immersion liquid.

[0063] A second drain 12 (which is located radially inwardly of the edge of the substrate W / support body 21) is provided to help prevent liquid flowing from the gap 5 under the substrate W from hindering efficient release of the substrate W from the substrate table WT after imaging. The provision of the second drain 12 reduces or eliminates any problems that may arise due to liquid flowing under the substrate W.

[0064] like Figure 4 As shown, in one embodiment, the lithographic apparatus includes a first extraction channel 102 for passing a two-phase flow. The first extraction channel 102 is formed in the support body 21. The first exhaust port 10 and the second exhaust port 12 are each provided with a corresponding opening 107, 117 and a corresponding extraction channel 102, 113. The extraction channels 102, 113 are in fluid communication with the corresponding openings 107, 117 through corresponding channels 103, 114.

[0065] like Figure 4As shown, the cover ring 101 has an upper surface. The upper surface extends circumferentially around the substrate W on the support body 21. When the lithographic apparatus is in use, the fluid handling structure IH moves relative to the substrate support 20. During this relative movement, the fluid handling structure IH moves through the gap 5 between the cover ring 101 and the substrate W. In one embodiment, the relative movement is caused by the substrate support 20 moving under the fluid handling structure IH. In another embodiment, the relative movement is caused by the fluid handling structure IH moving on the substrate support 20. In another alternative embodiment, the relative movement is provided by both the substrate support 20 moving under the fluid handling structure IH and the fluid handling structure IH moving on the substrate support 20. In the following description, the movement of the fluid handling structure IH will be used to represent the relative movement of the fluid handling structure IH relative to the substrate support 20.

[0066] In both EUV and DUV systems, the substrate W held on the substrate support 20 may warp. That is, the shape of the substrate W is deformed so that it is not completely flat. Typical shape deformations of the substrate W are bowl-shaped and umbrella-shaped. This shape deformation of the substrate W can be at least partially corrected by moving a portion of the substrate W toward or away from the substrate support 20 in the z direction. However, there is currently no known technology that can be used to quickly provide such movement outside the last row of bumps. Therefore, the shape deformation at the periphery (i.e., the edge region) of the substrate W can be the main cause of overlay errors.

[0067] Embodiments address the above-mentioned problems by providing a new technique for moving the periphery of a substrate W in the z-direction to at least partially correct the shape deformation of the substrate W.

[0068] Figure 5 A substrate supporting device for an EUV system according to a first embodiment is schematically shown.

[0069] The substrate support device includes a substrate support 20 and a substrate forming system 700. The substrate support 20 may be the substrate support 20 described above. Figure 1 and Figure 2 The substrate support 20 can provide a support plane, which is a substantially planar support surface of the substrate W. Figure 2 As described above with reference to the supporting plane 24 , the supporting surface 24 may be provided by the distal ends 23 of the plurality of protrusions 22 .

[0070] The substrate shaping system 700 includes at least one substrate shaping device 701. When a substrate W is disposed on a support surface, each substrate shaping device 701 is arranged to apply an electrostatic force to the periphery of the substrate W. Each substrate shaping device 701 may include an electrode arrangement configured to generate an electrostatic force applied by the substrate shaping device 701 to the substrate W. Each electrode arrangement may include a ground electrode 706 and a force generating electrode 702. Figure 5 As shown, the ground electrode 706 can be provided on the upper surface of a portion of the substrate forming device 701 or embedded therein. The force generating electrode 702 can be provided on the lower surface of a portion of the substrate forming device 701 or embedded therein. The force generating electrode 702 can be located above the substrate W so that the applied electrostatic force moves the substrate W away from the substrate support 20. The electrostatic force applied to the substrate W can be generated by the potential difference between the force generating electrode 702 and the substrate W. The substrate support device may further include a controller (not shown) that is arranged to control the magnitude of the potential difference between the ground electrode 706 and the force generating electrode 702. The magnitude of the electrostatic force applied by the force generating electrode 702 can depend on the potential difference between the ground electrode 706 and the force generating electrode 702. Thus, the controller can control the magnitude of the electrostatic force applied to the substrate W.

[0071] The substrate shaping system 700 may include a plurality of substrate shaping devices 701. In a plan view, the plurality of substrate shaping devices 701 may be arranged around a support surface. The plurality of substrate shaping devices 701 may be equally spaced around the circumference of the support surface. Each substrate shaping device 701 may be configured to apply an electrostatic force to a different portion of the substrate W. The substrate shaping devices 701 may be independently controllable. Thus, the substrate shaping devices 701 may be configured to independently apply an electrostatic force to different portions of the periphery of the substrate W.

[0072] Each substrate forming device 701 is movable between a first position and a second position. In the first position, the substrate forming device 701 may be located near and above the periphery of the substrate W. Electrostatic force is a short-range force. Positioning the substrate forming device 701 near and above the periphery of the substrate W ensures that the electrostatic force is applied to the periphery of the substrate W. As the distance between the central region of the substrate W and the force generating electrode 702 increases, it is substantially unaffected by the electrostatic force.

[0073] When each substrate forming device 701 is in its first position, it may be difficult to load a substrate W onto the substrate support 20 due to the risk of collision between the substrate W and at least one substrate forming device. To address this issue, each substrate forming device 701 may be movable to a second position, in which each substrate forming device 701 may be located further from the midpoint of the substrate support 20. When each substrate forming device 701 is in its second position, the substrate W may be easily positioned on the substrate support 20. Thus, each substrate forming device 701 may be moved to its second position during loading and unloading of the substrate W, and moved to its first position when the substrate W is loaded onto the substrate support 20.

[0074] Figure 5 A substrate forming device 701 is schematically shown in a first position. The substrate forming device 701 may comprise a generally L-shaped portion of the substrate forming system 700. When in the first position, the substrate forming device 701 may be arranged to overhang the periphery of the substrate W. An xy-direction separation distance 705 exists between the edge of the substrate W and the vertical rods of the substrate forming device 701. This separation distance 705 may be referred to as a lateral gap. A z-direction separation distance 704 exists between the upper surface of the substrate W at the periphery of the substrate W and the overhanging substrate forming device 701. This separation distance 705 may be referred to as a vertical gap.

[0075] To move between the first position and the second position, each substrate forming device 701 can be movable relative to the substrate support 20 in a direction parallel to the plane of the support surface, i.e., in a direction that increases or decreases the xy-direction separation distance 705. Each substrate forming device 701 can additionally or alternatively be movable relative to the substrate support 20 in a direction perpendicular to the plane of the support surface, i.e., in a direction that increases or decreases the z-direction separation distance 704. The substrate forming system 700 can include one or more piezoelectric actuators (not shown) for moving each substrate forming device 701 relative to the substrate support 20.

[0076] When each substrate-forming device 701 is in its first position, its force-generating electrodes 702 are arranged so that the electrostatic force applied to the substrate W includes a component that is perpendicular to the plane of the support surface and is directed to move the substrate W away from the support surface. The force-generating electrodes 702 can be located at the periphery of the substrate W, directly above the upper surface of the substrate W, such that the electrostatic force is at an angle of approximately 90° to the plane of the support surface. Alternatively, the force-generating electrodes 702 can be located at the periphery of the substrate W, above the upper surface of the substrate W and laterally away from the upper surface, such that the electrostatic force is at an angle of approximately 80° to the plane of the support surface.

[0077] The first position of each substrate forming device 701 can be changed based on the actual shape of the substrate W currently loaded on the substrate support 20. The type of substrate shape deformation that may need to be corrected may be a bowl shape or an umbrella shape. The degree of substrate shape deformation will also vary between substrates W. If the first position of each substrate forming device is a fixed predetermined position for all substrates W, then each substrate forming device 701 may not be sufficiently close to the surface of the substrate W due to variations in the actual shape of the substrate W. Therefore, to ensure that the first position of each substrate forming device 701 is sufficiently close to the surface of the substrate W, the first position of each substrate forming device 701 can be determined based on the actual shape of the substrate W currently loaded on the substrate support 20.

[0078] To determine the appropriate first position of each substrate forming device 701, the substrate forming system 700 may include a sensor system (not shown) configured to determine the relative position of each substrate forming device 701 and the substrate W. For example, the sensor system may determine the size of the xy-direction separation distance 705 and / or the z-direction separation distance 704. The sensor system may include one or more capacitors and / or light sources for determining / measuring the size of the xy-direction separation distance 705 and / or the z-direction separation distance 704.

[0079] The appropriate first position of each substrate forming device 701 can be determined as a position where the xy-direction spacing distance 705 and / or the z-direction spacing distance 704 are within a predetermined range. For example, the movement of each substrate forming device 701 can be controlled by the controller so that its xy-direction spacing distance 705 is less than or equal to 10 μm and its z-direction spacing distance 704 is less than or equal to 10 μm.

[0080] The substrate shaping system 700 described above applies an electrostatic force to the periphery of the substrate W, wherein the applied electrostatic force moves the substrate W away from the substrate support 20 .

[0081] Embodiments also include techniques for applying an electrostatic force to the periphery of the substrate W, wherein the applied electrostatic force causes the substrate W to move toward the substrate support 20 .

[0082] like Figure 5As shown, embodiments include providing one or more additional force generating electrodes 703. Each of the one or more additional force generating electrodes 703 can be disposed on or embedded in the surface of the substrate support 20 and / or surrounding structures of the substrate support 20. The one or more additional force generating electrodes 703 can be positioned such that when the substrate W is loaded onto the substrate support 20, the one or more additional force generating electrodes 703 are located below the periphery of the substrate W. There can be a plurality of additional force generating electrodes 703. In a plan view, the plurality of additional force generating electrodes 703 can be arranged around the support surface. The plurality of additional force generating electrodes 703 can be equally spaced around the circumference of the support surface. Each additional force generating electrode 703 can be arranged to apply an electrostatic force to a different portion of the substrate W. The plurality of additional force generating electrodes 703 can be independently controllable. Thus, the additional force generating electrodes 703 can be arranged to independently apply an electrostatic force to different portions of the periphery of the substrate W.

[0083] Each of the one or more additional force generating electrodes 703 can be electrically insulated. The substrate support 20 and / or surrounding structures of the substrate support 20 can be electrically grounded. For each of the one or more additional force generating electrodes 703, an electric potential difference can be generated between the force generating electrode 703 and ground. Each additional force generating electrode 703 can apply an electrostatic force to the substrate W, wherein the applied force depends on the electric potential difference. A controller (not shown) can control each electric potential difference, thereby controlling the electrostatic force applied by each of the one or more additional force generating electrodes 703.

[0084] Thus, the one or more further force generating electrodes 703 may generate an electrostatic force to move the substrate W towards the substrate support 20 .

[0085] Advantageously, the first embodiment provides a technique for moving the periphery of a substrate W toward and / or away from the plane of the substrate W's support surface. Consequently, any shape deformation at the edge of the substrate W can be at least partially corrected by applying a force to the substrate W to correct the shape deformation. The applied force can be substantially perpendicular to the substrate W's support plane. This avoids applying significant lateral forces to the substrate W. The use of electrostatic forces is preferable to contacting the substrate W to directly apply mechanical forces, which could damage the substrate.

[0086] According to a second embodiment, a technique is provided for changing the shape of a substrate W in a DUV system to at least partially correct shape deformation of the substrate W. Similar to the first embodiment, the second embodiment also applies electrostatic force to the periphery of the substrate W using force generating electrodes.

[0087] In a DUV system, immersion fluid is present between at least a portion of the surface of the substrate W and the projection system PS. If immersion fluid flows into the region between the force generating electrodes and the substrate W, the immersion fluid will significantly attenuate the electrostatic force applied to the substrate W. The second embodiment includes at least one seal to ensure that there is substantially no immersion fluid between each force generating electrode and the substrate W.

[0088] Figure 6 A substrate supporting device for a DUV system according to a second embodiment is schematically shown.

[0089] The substrate support device includes a substrate support 20 and a substrate forming system 800. The substrate support 20 may be the substrate support 20 described above. Figure 3 and Figure 4 The substrate support 20 may provide a support plane, which is a substantially planar support surface for the substrate W. The support surface may be defined by distal ends of the plurality of bumps 41 .

[0090] The substrate shaping system 800 includes at least one substrate shaping device 802 and at least one pedestal 801. When a substrate W is disposed on a support surface, each substrate shaping device 802 is arranged to apply an electrostatic force to the periphery of the substrate W. Each substrate shaping device 802 may include an electrode arrangement configured to generate an electrostatic force applied by the substrate shaping device 802 to the substrate W. Each electrode arrangement may include a ground electrode 803 and at least one force generating electrode 804, 805. Figure 6 As shown, each ground electrode 803 may be disposed on an upper surface of a portion of the substrate forming device 802 or embedded therein.

[0091] Figure 6 An upper force generating electrode 804 and a lower force generating electrode 805 are shown. The upper force generating electrode 804 can be located directly above the lower force generating electrode 805. The upper force generating electrode 804 can be located directly below the ground electrode 803. Both the upper force generating electrode 804 and the lower force generating electrode 805 can be proximate to the substrate-facing edge of the substrate forming device 802. The upper force generating electrode 804 can be disposed on an upper surface of a portion of the substrate forming device 802 or embedded therein. The lower force generating electrode 805 can be disposed on a lower surface of a portion of the substrate forming device 802 or embedded therein.

[0092] A controller (not shown) can generate a potential difference between the ground electrode 803 and the upper force generating electrode 804 and / or the lower force generating electrode 805. This causes an electrostatic force to be applied to the substrate W by the upper force generating electrode 804 and / or the lower force generating electrode 805. The upper force generating electrode 804 can be positioned farther from the support surface than the upper surface of the substrate W. The lower force generating electrode 804 can be positioned closer to the support surface than the lower surface of the substrate W. The electrostatic forces applied to the periphery of the substrate W by the upper force generating electrode 804 and the lower force generating electrode 805 can both include xy-direction components and z-direction components. The z-direction component of the electrostatic force applied by the upper force generating electrode 804 can be used to move the periphery of the substrate W away from the support plane. The z-direction component of the electrostatic force applied by the lower force generating electrode 804 can be used to move the periphery of the substrate W toward the support plane. Thus, the upper force generating electrode 804 and the lower force generating electrode 805 may be used to apply a force to the periphery of the substrate W, which force respectively moves the periphery of the substrate W away from or towards the support plane. As described with respect to the first embodiment, the substrate support apparatus may include a controller arranged to control the magnitude of the potential difference between the ground electrode 803 and the upper force generating electrode 804 and / or the lower force generating electrode 805.

[0093] In a preferred implementation of the second embodiment, the upper force generating electrode 804 is positioned so that the direction of the electrostatic force applied by the upper force generating electrode 804 to the periphery of the substrate W is at an angle of approximately 80° to the plane of the support surface. Preferably, the lower force generating electrode 805 is also positioned so that the direction of the electrostatic force applied by the lower force generating electrode 805 to the periphery of the substrate W is at an angle of approximately 80° to the plane of the support surface.

[0094] The ground electrode 803 may be at least partially located on an upper surface of the substrate forming device 802. The ground electrode 803 may be substantially coplanar with an upper surface of the substrate W.

[0095] In this embodiment, a seal 807 is present that covers the substrate forming device 802 and at least a portion of the substrate W. The seal 807 may extend in the xy direction from above the substrate forming device 802 to above the upper surface of the substrate W. The seal 807 may be a liquid seal that substantially prevents any immersion fluid on the upper surface of the substrate W from flowing over the edge of the substrate W. The seal 807 ensures that there is substantially no immersion fluid between the periphery of the substrate W and the upper force generating electrode 804 or the lower force generating electrode 805.

[0096] The substrate shaping system 800 may include a plurality of substrate shaping devices 802. In a plan view, the plurality of substrate shaping devices 802 may be arranged around a support surface. The plurality of substrate shaping devices 802 may be equally spaced around the circumference of the support surface. Each substrate shaping device 802 may be configured to apply an electrostatic force to a different portion of the substrate W. The substrate shaping devices 802 may be independently controllable. Thus, the substrate shaping devices 802 may be configured to independently apply an electrostatic force to different portions of the periphery of the substrate W.

[0097] As described with respect to the first embodiment, each substrate forming device 802 can be movable between a first position and a second position. In the first position, the substrate forming device 802 can be located close to the periphery of the substrate W so that it can apply an electrostatic force to the periphery of the substrate W. The second position of each substrate forming device 802 can be located further from the midpoint of the substrate support 20 so that the substrate W can be easily positioned on the substrate support 20. Therefore, each substrate forming device 802 can be moved to its second position during loading and unloading of the substrate W, and moved to its first position when the substrate W is loaded onto the substrate support 20.

[0098] Figure 6 The substrate shaping device 802 is schematically shown in a first position. Between the edge of the substrate W and the substrate-facing edge of the substrate shaping device 802 there is an xy-direction separation distance 806, which may be referred to as a lateral gap.

[0099] To move between the first position and the second position, each substrate forming device 802 may be movable relative to the substrate support 20 in a direction parallel to the plane of the support surface, i.e., in a direction that increases or decreases the xy-direction separation distance 806. Each substrate forming device 802 may be located on a base 801 that includes one or more piezoelectric actuators (not shown) for moving the substrate forming device 802 relative to the substrate support 20.

[0100] As described with respect to the first embodiment, in order to determine the appropriate first position of each substrate forming device 802, the substrate forming system 800 may include a sensor system (not shown) configured to determine the relative position of each substrate forming device 802 and the substrate W. For example, the sensor system may determine the size of the xy-direction separation distance 806. The sensor system may include one or more capacitors and / or light sources for determining / measuring the size of the xy-direction separation distance 806. The appropriate first position of each substrate forming device 802 may be determined as a position where the size of the xy-direction separation distance 806 is within a predetermined range. For example, the movement of each substrate forming device 802 may be controlled by a controller so that its xy-direction separation distance 806 is less than or equal to 10 μm.

[0101] Figure 7 A portion of a seal 807 according to an embodiment is schematically shown. The seal 807 may be a mechanical edge seal (MES). The seal 807 may include a groove 901 in its surface facing the substrate. An immersion fluid (which may be water) may be present in a fluid region 903 above the substrate W. Due to surface tension, the immersion fluid forms a meniscus 902 at the edge of the groove 901, preventing the immersion fluid from flowing further along the length of the seal 807. Thus, the groove 901 provides a capillary stop. Advantageously, the seal 807 does not physically contact the substrate W. Furthermore, the presence of the seal 807 reduces the amount of immersion fluid that flows over the edge of the substrate W, thereby reducing both the heat load and the variation in heat load experienced by each substrate W. Additionally or alternatively, gas may be supplied to a region below the periphery of the substrate W to increase the gas pressure. The overpressure of the gas may reduce or prevent the flow of immersion liquid over the edge of the substrate W.

[0102] The seal 807 can be static or movable. In plan view, the static seal 807 can be a single annular structure that covers the entire circumference of the substrate W. When the static seal 807 is used, the seal 807 can maintain its relative position relative to the substrate W as each substrate forming device 802 moves between its first position and second position. After the substrate W is loaded onto the substrate support 20, the static seal 807 can be positioned above the substrate W using a separate mechanism. Before the substrate W is unloaded, the static seal 807 can be moved from above the substrate W using the same mechanism.

[0103] Alternatively, to provide a movable seal 807, a seal 807 can be fixed to each substrate forming device 802. In plan view, each seal 807 can be shaped like a truncated sector of a circle. As the substrate forming device 802 moves between its first and second positions, each seal 807 can move with the substrate forming device 802 to which it is fixed. When all of the plurality of substrate forming devices 802 are in their first positions, their seals 807 can contact one another, thereby combining to form an annular seal around the circumference of the substrate W in plan view.

[0104] In a manner similar to the first embodiment, in the second embodiment, one or more additional force generating electrodes 808 may be disposed on or embedded in the surface of the substrate support 20 and / or surrounding structures of the substrate support 20. The one or more additional force generating electrodes 808 may be positioned such that, when a substrate W is loaded onto the substrate support 20, the one or more additional force generating electrodes 808 are located below the periphery of the substrate W. There may be a plurality of additional force generating electrodes 808. In a plan view, the plurality of additional force generating electrodes 808 may be arranged around the support surface. The plurality of additional force generating electrodes 808 may be equally spaced around the circumference of the support surface. Each additional force generating electrode 808 may be arranged to apply an electrostatic force to a different portion of the substrate W. The plurality of additional force generating electrodes 808 may be independently controllable. Thus, the additional force generating electrodes 808 may be arranged to independently apply an electrostatic force to different portions of the periphery of the substrate W.

[0105] Each of the one or more additional force generating electrodes 808 can be electrically isolated. The substrate support 20 and / or surrounding structures of the substrate support 20 can be electrically grounded. For each of the one or more additional force generating electrodes 808, an electric potential difference can be generated between the force generating electrode 808 and ground. Each additional force generating electrode 808 can apply an electrostatic force to the substrate W, wherein the applied force depends on the electric potential difference. A controller can control each electric potential difference, thereby controlling the electrostatic force applied by each additional force generating electrode in the one or more additional force generating electrodes 808.

[0106] Thus, the one or more further force generating electrodes 808 may generate an electrostatic force to move the substrate W towards the substrate support 20 .

[0107] The above-described embodiments provide a new technique for at least partially correcting shape deformation of a substrate W. An electrostatic force may be applied to the periphery of the substrate W to change the shape of the substrate W, thereby reducing deformation of the substrate W. The technique of the embodiments may be applied to both EUV and DUV systems.

[0108] Embodiments include many modifications and variations of the above-described techniques.

[0109] In the first and second embodiments, it is optional to provide the force generating electrodes 703, 808 on the surface of or embedded in the substrate support 20 and / or surrounding structures of the substrate support 20. At least partial correction of the umbrella deformation of the substrate W is still possible.

[0110] In the second embodiment, the provision of the lower force generating electrode 805 is optional. The electrode arrangement of each substrate forming device 802 may only include the ground electrode 803 and the upper force generating electrode 804.

[0111] The use of a capillary stop in the seal 807 is optional. The seal 807 may instead contact the upper surface of the substrate W.

[0112] Figure 5 The substrate shaping device 701 shown can be adjusted so that the end of the portion overhanging the substrate W includes a groove (not shown). The groove can be similar to the reference Figure 7 The groove 901 is described so that it can be a capillary stop. A capillary stop is not required in a vacuum system (such as an EUV system) because there is no liquid on the surface of the substrate W. However, providing the substrate forming device 701 with a capillary stop can allow the same substrate forming device 701 to be used in both EUV and DUV systems.

[0113] Figure 2 The bump arrangement shown is exemplary. Embodiments include embodiments in which the number of bumps 22, 41 protruding from the surface facing the substrate W is much greater than the number of bumps further away from the substrate W.

[0114] Although specific reference may be made herein to the use of lithographic apparatus in IC manufacturing, it should be understood that the lithographic apparatus described herein may have other applications. Other possible applications include 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, and the like.

[0115] Although specific reference may be made herein to embodiments of the present invention in the context of lithographic apparatus, embodiments of the present invention may also be used in other apparatus. Embodiments of the present invention may form part of a mask inspection apparatus, a metrology apparatus, or any apparatus for measuring or processing 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 vacuum conditions or ambient (non-vacuum) conditions.

[0116] Although specific reference may be made above to the use of embodiments of the invention in the context of object inspection and / or optical lithography, it will be appreciated that the invention is not limited to these contexts and may also be used in other applications, such as imprint lithography, where the context permits.

[0117] The Examples include the following numbered sections:

[0118] 1. A substrate support device configured to support a substrate, the substrate support device comprising:

[0119] a substrate support having a substantially planar support surface for the substrate; and

[0120] a substrate forming system comprising one or more substrate forming devices;

[0121] wherein each substrate forming device is movable relative to the substrate support; and

[0122] Wherein each substrate shaping device is arranged to apply an electrostatic force to a periphery of the substrate when the substrate is disposed on the support surface.

[0123] 2. The substrate support apparatus according to section 1, wherein each substrate shaping device is arranged to move relative to the substrate support in a direction parallel to the plane of the support surface.

[0124] 3. A substrate support apparatus according to section 1 or 2, wherein each substrate shaping device is arranged to move relative to the substrate support in a direction perpendicular to the plane of the support surface.

[0125] 4. A substrate support apparatus according to any one of the preceding sections, wherein the substrate shaping system comprises a plurality of substrate shaping devices, and in a plan view, the plurality of substrate shaping devices are arranged around the support surface.

[0126] 5. The substrate support device according to any of the preceding sections, further comprising one or more piezoelectric actuators;

[0127] Each piezoelectric actuator is arranged to move at least one substrate shaping device relative to the substrate support.

[0128] 6. A substrate support apparatus according to any of the preceding sections, wherein each substrate shaping device comprises an electrode arrangement configured to generate the electrostatic force applied by the substrate shaping device.

[0129] 7. The substrate support device according to Section 6, wherein the electrode arrangement comprises a ground electrode and a force generating electrode; and

[0130] The ground electrode and the force generating electrode are arranged such that, when a substrate is disposed on the support surface, the electrostatic force is generated between the force generating electrode and the periphery of the substrate.

[0131] 8. The substrate supporting device according to Chapter 7 further includes a controller, which is arranged to control the magnitude of the potential difference between the ground electrode and the force generating electrode of each substrate forming device, thereby controlling the magnitude of the electrostatic force applied by the substrate forming device.

[0132] 9. A substrate support device according to section 7 or 8, wherein the force generating electrodes are arranged so that: when the substrate is set on the support surface, the electrostatic force applied by each substrate forming device includes a component perpendicular to the plane of the support surface and is directed to move the substrate away from the support surface.

[0133] 10. A substrate support device according to any one of Chapters 7 to 9, wherein the force generating electrodes are arranged so that: when the substrate is set on the support surface, the electrostatic force applied by each substrate forming device is directed at an angle of approximately 90° to the plane of the support surface.

[0134] 11. A substrate support device according to any one of Chapters 7 to 9, wherein the force generating electrodes are arranged so that: when the substrate is set on the support surface, the electrostatic force applied by each substrate forming device is directed at an angle of approximately 80° to the plane of the support surface.

[0135] 12. A substrate support apparatus according to any one of Chapters 7 to 11, wherein the force generating electrode of each substrate forming device is embedded within the substrate forming device.

[0136] 13. The substrate support device according to any one of Chapters 7 to 12, wherein the ground electrode of each substrate forming device is located on the upper surface of the substrate forming device.

[0137] 14. The substrate support apparatus of any one of Sections 7 to 13, wherein each substrate shaping device comprises more than one force generating electrode; and

[0138] At least one force generating electrode is arranged such that, when a substrate is disposed on the support surface, the electrostatic force applied by each substrate shaping device includes a component perpendicular to the plane of the support surface and directed to move the substrate towards the support surface.

[0139] 15. A substrate support apparatus according to any of the preceding clauses, wherein when a substrate is disposed on the support surface, a lateral gap is formed between an edge of the substrate and an edge of each substrate forming device.

[0140] 16. The substrate support device according to Section 15, further comprising a sensor system configured to measure the size of each lateral gap.

[0141] 17. The substrate support apparatus of clause 16, further comprising a controller configured to control the movement of each substrate forming device according to the measured size of each lateral gap.

[0142] 18. The substrate support apparatus according to Section 17, wherein the controller is configured to control the movement of each substrate forming device so that each lateral gap is less than or equal to 10 μm.

[0143] 19. A substrate support apparatus according to any one of Chapters 15 to 18, wherein the upper surface of each substrate forming device is substantially coplanar with the upper surface of the substrate when the substrate is disposed on the support surface.

[0144] 20. The substrate support device according to Section 19, further comprising one or more seals;

[0145] wherein each seal is arranged such that, when a substrate is disposed on the support surface, each seal spans the lateral gap formed between the edge of the substrate and the edge of each substrate-forming device.

[0146] 21. The substrate support device according to Section 20, wherein each seal is arranged not to contact the substrate when the substrate is placed on the support surface.

[0147] 22. A substrate support device according to Chapter 20 or 21, wherein each seal comprises a capillary stop when the substrate is disposed on the support surface.

[0148] 23. A substrate support device according to any one of Chapters 1 to 14, wherein when a substrate is set on the support surface, each substrate forming device is moved so that a vertical gap is formed between the upper surface of the substrate and the lower surface of each substrate forming device.

[0149] 24. The substrate support device according to Section 23, further comprising a sensor system configured to measure the size of each vertical gap.

[0150] 25. The substrate support apparatus according to Section 24, further comprising a controller configured to control the movement of each substrate forming device according to the measured size of each vertical gap.

[0151] 26. The substrate support apparatus according to Section 25, wherein the controller is configured to control the movement of each substrate forming device so that each vertical gap is less than or equal to 10 μm.

[0152] 27. The substrate support device according to any of the preceding sections, further comprising one or more further force generating electrodes embedded in the substrate support and / or in a surrounding structure of the substrate support;

[0153] wherein the one or more further force generating electrodes are arranged such that: when a substrate is disposed on the support surface, each of the one or more further force generating electrodes is arranged to apply an electrostatic force to the periphery of the substrate; and

[0154] Each electrostatic force includes a component that is perpendicular to the plane of the support surface and is directed to move the substrate toward the support surface.

[0155] 28. A substrate support device according to Chapter 27, wherein a plurality of additional force generating electrodes are embedded in the substrate support and / or the surrounding structure of the substrate support, and in a plan view, the plurality of additional force generating electrodes are arranged around the support surface.

[0156] 29. A lithographic apparatus comprising a substrate support device according to any one of the preceding sections.

[0157] 30. A method for changing the shape of a substrate, the method comprising:

[0158] loading a substrate onto the substrate support of the substrate support device according to any one of Sections 1 to 28; and

[0159] An electrostatic force is applied to the periphery of the substrate.

[0160] Although specific embodiments of the present invention have been described above, it should be understood that the present invention may be practiced in other ways than those described. The above description is intended to be illustrative and not limiting. Therefore, it will be understood by those skilled in the art that modifications may be made to the described invention without departing from the scope of the following claims.

Claims

1. A substrate support device configured to support a substrate, the substrate support device comprising: a substrate support having a substantially planar support surface for a substrate; as well as a substrate forming system comprising one or more substrate forming devices; wherein each substrate shaping device is movable relative to the substrate support; and Wherein each substrate shaping device is arranged to apply an electrostatic force to a periphery of the substrate when the substrate is disposed on the support surface.

2. A substrate support device according to claim 1, wherein each substrate forming device is arranged to move relative to the substrate support in a direction parallel to the plane of the support surface, and / or wherein each substrate forming device is arranged to move relative to the substrate support in a direction perpendicular to the plane of the support surface.

3. A substrate support device according to claim 1 or 2, wherein the substrate forming system comprises a plurality of substrate forming devices, and in a plan view, the plurality of substrate forming devices are arranged around the support surface, and / or the substrate support device further comprises one or more piezoelectric actuators, wherein each piezoelectric actuator is arranged to move at least one substrate forming device relative to the substrate support, and / or wherein each substrate forming device comprises an electrode arrangement, which is configured to generate the electrostatic force applied by the substrate forming device.

4. The substrate support device of claim 3 , wherein the electrode arrangement comprises a ground electrode and a force generating electrode; and The ground electrode and the force generating electrode are arranged such that, when a substrate is disposed on the support surface, the electrostatic force is generated between the force generating electrode and the periphery of the substrate.

5. The substrate support apparatus according to claim 4 , further comprising a controller arranged to control the magnitude of the potential difference between the ground electrode and the force generating electrode of each substrate shaping device, thereby controlling the magnitude of the electrostatic force applied by the substrate shaping device, and / or wherein the force generating electrodes are arranged such that, when a substrate is disposed on the support surface, the electrostatic force applied by each substrate shaping device includes a component that is perpendicular to the plane of the support surface and is directed to move the substrate away from the support surface, and / or wherein the force generating electrodes are arranged such that, when a substrate is disposed on the support surface, the electrostatic force applied by each substrate shaping device is directed at an angle of approximately 90° to the plane of the support surface, and / or wherein the force generating electrodes are arranged such that, when a substrate is disposed on the support surface, the electrostatic force applied by each substrate shaping device is directed at an angle of approximately 80° to the plane of the support surface.

6. The substrate support device according to claim 5, wherein the force generating electrode of each substrate forming device is embedded in the substrate forming device, and / or wherein the ground electrode of each substrate forming device is located on the upper surface of the substrate forming device, and / or wherein each substrate forming device includes more than one force generating electrode; and At least one force generating electrode is arranged such that, when a substrate is disposed on the support surface, the electrostatic force applied by each substrate shaping device includes a component perpendicular to the plane of the support surface and directed to move the substrate towards the support surface.

7. A substrate support arrangement according to any one of the preceding claims, wherein when a substrate is arranged on the support surface, a lateral gap is formed between an edge of the substrate and an edge of each substrate forming device.

8. The substrate support device according to claim 7 further includes a sensor system configured to measure the size of each lateral gap, and desirably further includes a controller configured to control the movement of each substrate forming device based on the measured size of each lateral gap, desirably, wherein the controller is configured to control the movement of each substrate forming device so that each lateral gap is less than or equal to 10 μm, and / or wherein when the substrate is set on the support surface, the upper surface of each substrate forming device is substantially coplanar with the upper surface of the substrate.

9. The substrate support apparatus of claim 8, further comprising one or more seals; wherein each seal is arranged such that, when a substrate is disposed on the support surface, each seal spans the lateral gap formed between the edge of the substrate and the edge of each substrate-forming device.

10. The substrate support device of claim 9, wherein each seal is arranged not to contact the substrate when the substrate is disposed on the support surface, and / or wherein each seal comprises a capillary stop when the substrate is disposed on the support surface.

11. The substrate support apparatus according to any one of claims 1 to 6, wherein when a substrate is disposed on the support surface, each substrate forming device is moved so that a vertical gap is formed between an upper surface of the substrate and a lower surface of each substrate forming device.

12. The substrate support device according to claim 11 further includes a sensor system configured to measure the size of each vertical gap, and preferably also includes a controller configured to control the movement of each substrate forming device according to the measured size of each vertical gap, preferably, wherein the controller is configured to control the movement of each substrate forming device so that each vertical gap is less than or equal to 10μm.

13. The substrate support device according to any of the preceding claims, further comprising one or more further force generating electrodes embedded in the substrate support and / or in a surrounding structure of the substrate support; wherein the one or more further force generating electrodes are arranged such that: when a substrate is disposed on the support surface, each of the one or more further force generating electrodes is arranged to apply an electrostatic force to the periphery of the substrate; and Each electrostatic force comprises a component perpendicular to the plane of the support surface and directed to move the substrate towards the support surface, desirably wherein a plurality of further force generating electrodes are embedded in the substrate support and / or in the surrounding structure of the substrate support and, in plan view, are arranged around the support surface.

14. A lithographic apparatus comprising a substrate support device according to any preceding claim.

15. A method for changing the shape of a substrate, the method comprising: loading a substrate onto the substrate support of the substrate support device according to any one of claims 1 to 13; as well as An electrostatic force is applied to the periphery of the substrate.

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