阅读说明：本技术 用于修改支撑表面的工具 (Tool for modifying a support surface ) 是由 B·D·肖尔滕 P·A·M·比勒肯斯 关天男 T·林德伊杰 H·A·梅哈格诺尔 J·M·W 于 2019-06-27 设计创作，主要内容包括：一种用于修改衬底保持器(20)的衬底支撑元件(21)的工具(1),所述衬底支撑元件具有用于支撑衬底的支撑表面(22),所述工具包括具有主体表面(3)的主体(2),其中所述工具包括自所述主体表面的多个突起部(4),所述多个突起部具有被配置成接触所述支撑表面并且修改所述衬底支撑元件的远端(5)。此外,公开了一种光刻设备和包括这种工具的方法。(A tool (1) for modifying a substrate support element (21) of a substrate holder (20), the substrate support element having a support surface (22) for supporting a substrate, the tool comprising a body (2) having a body surface (3), wherein the tool comprises a plurality of protrusions (4) from the body surface, the plurality of protrusions having distal ends (5) configured to contact the support surface and modify the substrate support element. Furthermore, a lithographic apparatus and a method comprising such a tool are disclosed.)

1. A tool for modifying a substrate support element of a substrate holder, the substrate support element having a support surface for supporting a substrate, the tool comprising a body having a body surface, wherein the tool comprises a plurality of projections from the body surface, the plurality of projections having distal ends configured to contact the support surface to modify the substrate support element.

2. The tool of claim 1, wherein the pitch between adjacent projections is greater than or equal to about 5mm, or preferably greater than or equal to about 7mm, or more preferably greater than or equal to about 12 mm.

3. The tool of claim 1 or claim 2, wherein at least one of the plurality of projections has a thickness greater than or equal to about 9mm²Or more preferably greater than or equal to about 20mm²Cross-sectional area of (a).

4. The tool of claim 1, wherein the distal end of at least one of the plurality of protrusions comprises a plurality of protrusions, wherein a distance between adjacent protrusions of the plurality of protrusions is between about 50nm and 1 mm.

5. The tool of claim 4, wherein the plurality of protrusions extend between about 50nm and 1mm from the distal end.

6. The tool of claim 1, wherein a distance between adjacent projections of the plurality of projections is between about 50nm and 1 mm.

7. The tool of claim 6, wherein the distance between the distal end and the body surface 3 is between about 50nm and 1 mm.

8. The tool of claim 1,2, 4 or 6, wherein the body is plate-like.

9. The tool of claim 8, wherein the diameter of the body is less than or equal to about 50mm, or preferably less than or equal to about 35 mm.

10. The tool of claim 1,2, 4, or 6, wherein the tool does not include a through hole.

11. The tool of claim 1,2, 4, or 6, wherein the body surface is substantially flat.

12. The tool of claim 1,2, 4 or 6, wherein the tool comprises silicon-infiltrated silicon carbide, aluminum oxide and/or diamond-like carbon.

13. A method for modifying a substrate support element of a substrate holder, the substrate support element having a support surface for supporting a substrate, the method comprising:

providing a tool according to any one of claims 1 to 12;

contacting at least some of the support surfaces with the distal end of the protrusion of the tool and modifying the support surfaces using the tool.

14. A lithographic apparatus, comprising:

a substrate holder having a plurality of support elements configured to support a substrate;

a material removal device configured to modify the substrate supporting element of the substrate holder, the material removal device having a tool for modifying the substrate supporting element of the substrate holder according to any one of claims 1 to 12.

15. The lithographic apparatus of claim 14, further comprising:

a detector configured to detect a height deviation of one or more of the support elements that affects a flatness of a surface of the substrate supported on the substrate holder, wherein the tool is configured to modify a height of the one or more support elements corresponding to the detected height deviation of the support elements.

16. A method for modifying a substrate support element of a substrate holder, the substrate support element having a support surface for supporting a substrate, the method comprising:

providing a lithographic apparatus according to any of claims 14 to 15;

contacting at least some of the support surfaces with the distal end of the protrusion of the tool and modifying the support surfaces using the tool.

17. A lithographic apparatus, comprising:

an item holder having a plurality of support elements having support surfaces configured to support an item;

a material removal device configured to modify a support element of the article holder, the material removal device having a tool comprising a body having a body surface, wherein the tool comprises a plurality of projections from the body surface, the plurality of projections having distal ends configured to contact the support surface to modify the support element.

18. The lithographic apparatus of claim 17, further comprising:

a detector configured to detect a height deviation of one or more of the support elements that affects a surface flatness of the item supported on the item holder, wherein the tool is configured to modify a height of the one or more support elements corresponding to the detected height deviation of the support elements.

19. A method for modifying a support element of an item holder, the support element having a support surface for supporting an item, the method comprising:

providing a lithographic apparatus according to any of claims 17 to 18;

contacting at least some of the support surfaces with the distal end of the protrusion of the tool and modifying the support surfaces using the tool.

Technical Field

This application claims priority from european application 18185938.0, filed 2018 on month 7, 27 and incorporated herein by reference in its entirety.

Technical Field

The present invention relates to a tool for modifying a holder, a method for modifying a holder using the tool, and a lithographic apparatus comprising the tool.

Background

A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. For example, lithographic apparatus can be used in the manufacture of Integrated Circuits (ICs). In this case, a patterning device (alternatively referred to as a mask or a reticle) may be used to generate the circuit patterns to be formed on the various layers of the IC. The pattern can be transferred onto a target portion (e.g., comprising a portion of one or more dies) on a substrate (e.g., a silicon wafer). The transfer of the pattern is typically via imaging onto a layer of radiation-sensitive material (resist) disposed on the substrate. Generally, a single substrate will contain a network of adjacent target portions that are successively patterned. Conventional lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing an entire pattern onto the target portion at one time; and so-called scanners, in which each target portion is irradiated by scanning the pattern through the radiation beam in a given direction (the "scanning" -direction) while synchronously scanning the substrate parallel or anti-parallel to this direction. The pattern may also be transferred from the patterning device to the substrate by imprinting the pattern onto the substrate.

There is a continuing need to fabricate devices, such as integrated circuits, with smaller features. Integrated circuits and other micro devices are typically fabricated using optical lithography, but other fabrication techniques (such as imprint lithography, electron beam lithography, and nano-self assembly) are known.

During manufacture, the device is irradiated. It is important to ensure that the irradiation process is as accurate as possible. One of the problems with making the irradiation process as accurate as possible is to ensure that the device to be irradiated is in the correct position. To control the position of the device, a substrate holder may be used. Typically, the substrate will be supported by the substrate holder while the substrate is being irradiated. When the substrate is positioned on the substrate holder, friction between the substrate and the substrate holder may prevent the substrate from flattening above the surface of the substrate holder. To solve this problem, the substrate holder may be provided with support elements that minimize the contact area between the substrate and the substrate holder. In other cases, the support elements on the surface of the substrate holder may be referred to as nubs or projections. The support elements are generally regularly spaced (e.g., in a uniform array) and of uniform height, and define a very flat overall support surface on which the substrate can be positioned. The support member reduces the contact area between the substrate holder and the substrate, thereby reducing friction and allowing the substrate to move to a flatter position on the substrate holder.

The support member generally extends generally perpendicularly from a surface of the substrate holder. In operation, the back surface of the substrate is supported on the support element at a small distance from the main body surface of the substrate holder, in a position substantially perpendicular to the propagation direction of the projection beam. Thus, the top of the support element (i.e. the support surface) defines the effective support surface for the substrate instead of the body surface 3 of the substrate holder.

To avoid overlay errors during projection of the patterned beam of radiation onto the substrate, it is desirable that the top surface of the substrate is flat. Irregularities in the support surface of the substrate support may result in non-uniformity of the top surface of the substrate. Therefore, it is desirable to avoid non-uniformity of the substrate support.

The unevenness of the support surface may be caused by the difference between the heights of the materials constituting the support element itself. This is typically the case when a new substrate holder is manufactured. Wear may also result in non-uniformities. In a known embodiment, the substrate support comprises a substrate table WT (otherwise referred to as a chuck) on which a substrate holder having a support element is supported. In an alternative embodiment, the substrate table WT and the substrate holder may be integrated in a single unit. The non-uniformity may be the result of differences between the heights of the support elements or in the backside of the substrate holder or in the substrate table WT. Thus, care is taken to flush these elements. However, it has been found that irregularities may also result when assembling or mounting the substrate table WT and substrate holder (and any other components). Similar problems may also be encountered with support tables or holders for other articles that must be supported in a well-defined plane across the beam path, such as reflective patterning devices or transmissive patterning devices.

US2005/0061995a1 (the contents of which are incorporated herein by reference in their entirety) provides a lithographic projection apparatus comprising: a detector to detect a height deviation of the support element affecting a surface flatness of the article; height adjustment means arranged to independently modify the height of the support element material of each support element when the support table is operable in the apparatus; and a controller coupled between the detector and the height adjustment device and arranged to control the height adjustment device to adjust the height of the support element affecting the surface flatness of the article corresponding to the detected height deviation of the support element.

An in-situ height adjustment device is used to modify the height of material integrally formed into at least the top portion of each support element when the support table is in an operable position in the lithographic projection apparatus. By "operable" is meant that the support holder can be moved from an operable position to a pattern projection position in the apparatus without movement that would otherwise damage the support table assembly than during normal use. "integrally manufactured" refers to the material used to make the coating or other material layer on the support holder or support element, and not to incidental foreign matter such as contaminants. By adjusting the height of the support elements in an assembled support holder in a lithographic apparatus at such an operable position, reliable local and global height adjustments may be achieved.

The detector determines which support elements have a height deviation and the control unit controls the height adjustment means, for example, to remove a portion of material of a selected support element having an excessive height, but not to remove a portion of material from other support elements having an excessive height that is not excessive or below a threshold value.

The known tools and methods can still be modified to provide a support element with improved flatness. Additional or alternative methods and tools may be desired to achieve the preferred flatness in different ways. Furthermore, it is beneficial to obtain this flatness while also providing a desired level of roughness on the support member to provide some friction between the support member and the substrate.

Disclosure of Invention

It is desirable to provide an improved height adjustment tool or at least one alternative method for use in a lithographic apparatus with respect to cost of ownership, cost of goods and/or overlay quality. Furthermore, it is desirable to provide a method of using such an improved or alternative height adjustment tool and a lithographic apparatus comprising such an improved or alternative height adjustment tool.

According to the present invention, there is provided a tool for modifying substrate supporting elements of a substrate holder, the substrate supporting elements having a supporting surface for supporting a substrate, the tool comprising a body having a body surface, wherein the tool comprises a plurality of protrusions from the body surface, the plurality of protrusions having distal ends configured to contact the supporting surface to modify the substrate supporting elements.

According to the present invention, there is provided a method for modifying substrate support elements of a substrate holder, the substrate support elements having a support surface for supporting a substrate, the method comprising: providing a tool according to any one of claims 1 to 12; at least some of the support surfaces are brought into contact with the distal end of the protrusion of the tool, and the tool is used to modify the support surfaces.

According to the invention, there is provided a lithographic apparatus comprising: a substrate holder having a plurality of support elements configured to support a substrate; material removal device configured to modify a substrate supporting element of a substrate holder, the material removal device having a tool for modifying a substrate supporting element of a substrate holder according to any of claims 1 to 12.

According to the present invention, there is provided a method for modifying substrate support elements of a substrate holder, the substrate support elements having a support surface for supporting a substrate, the method comprising: providing a lithographic apparatus according to any of claims 14 to 15; at least some of the support surfaces are brought into contact with the distal end of the protrusion of the tool, and the tool is used to modify the support surfaces.

According to the invention, there is provided a lithographic apparatus comprising: an item holder having a plurality of support elements having support surfaces configured to support an item; a material removal device configured to modify a support element of an article holder, the material removal device having a tool comprising a body having a body surface, wherein the tool comprises a plurality of projections from the body surface, the plurality of projections having distal ends configured to contact the support surface to modify the support element.

According to the present invention, there is provided a method for modifying support elements of an article holder, the support elements having support surfaces for supporting an article, the method comprising: providing a lithographic apparatus according to any of claims 17 to 18; at least some of the support surfaces are brought into contact with the distal end of the protrusion of the tool, and the tool is used to modify the support surfaces.

Drawings

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

FIG. 1 depicts a lithographic apparatus;

figures 2A, 2B and 2C depict schematic views of the tool of the present invention;

fig. 3 depicts a cross-section of the tool of fig. 2A, 2B and 2C, which is used to modify a substrate holder;

figures 4A, 4B and 4C show a variant of the tool of the invention;

fig. 5 shows another variant of the tool of fig. 2A, 2B and 2C;

FIG. 6 shows another variant of the tool of FIGS. 2A, 2B and 2C, an

Figure 7 shows a further variant of the tool of the invention.

The figures provide an indication of certain features included in some embodiments of the invention. However, the drawings are not to scale. Examples of dimensions and dimensional ranges for certain features are described in the following description.

Detailed Description

FIG. 1 schematically depicts a lithographic apparatus according to one embodiment of the invention. The apparatus comprises: an illumination system (illuminator) IL configured to condition a radiation beam B (e.g. ultraviolet radiation or any other suitable radiation); a patterning device support or support structure (e.g. a mask table) MT constructed to support a patterning device (e.g. a mask) MA and connected to a first positioner PM configured to accurately position the patterning device in accordance with certain parameters. The lithographic apparatus also includes a substrate table (e.g. a wafer table) WT or "substrate support" constructed to hold a substrate (e.g. a resist-coated wafer) W and connected to a second positioner PW configured to accurately position the substrate in accordance with certain parameters. The substrate support may comprise a substrate table WT (otherwise referred to as a chuck) on which a substrate holder is supported. The substrate holder may be configured to support a substrate W. The apparatus also includes a projection system (e.g. a refractive projection lens system) PS configured to project a pattern imparted to the radiation beam B by patterning device MA onto a target portion C (e.g. comprising one or more dies) of the substrate W.

The illumination system may include various types of optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic or other types of optical components, or any combination thereof, for directing, shaping, or controlling radiation.

The patterning device support holds the patterning device MA in a manner that depends on the orientation of the patterning device MA, the design of the lithographic apparatus, and other conditions, such as for example whether or not the patterning device MA is held in a vacuum environment. The patterning device support may use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterning device. The patterning device support may be a frame or a table, for example, which may be fixed or movable as required. The patterning device support may ensure that the patterning device MA is at a desired position, for example with respect to the projection system PS. Any use of the terms "reticle" or "mask" herein may be considered synonymous with the more general term "patterning device".

The term "patterning device" used herein should be broadly interpreted as referring to any device that can be used to impart a radiation beam with a pattern in its cross-section such as to create a pattern in a target portion of the substrate. 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 of the substrate, for example if the pattern includes phase-shifting features or so called assist features. Generally, the pattern imparted to the radiation beam B will correspond to a particular functional layer in the device being created in the target portion, such as an integrated circuit.

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

The term "projection system" used herein should be broadly interpreted as encompassing any type of projection system, including refractive, reflective, catadioptric, magnetic, electromagnetic and electrostatic optical systems, or any combination thereof, as appropriate for the exposure radiation being used, or for 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 synonymous with the more general term "projection system".

As depicted herein, the apparatus is of a transmissive type (e.g., employing a transmissive mask). Alternatively, the apparatus may be of a reflective type (e.g. employing a programmable mirror array of a type as referred to above, or employing a reflective mask).

The lithographic apparatus may be of a type having two (dual stage) or more substrate tables or "substrate supports" (and/or two or more mask tables or "mask supports"). In such "multiple stage" machines the additional tables or supports may be used in parallel, or preparatory steps may be carried out on one or more tables or supports while one or more other tables or supports are being used for exposure.

The lithographic apparatus may also be of a type wherein at least a portion of the substrate W may be covered by a liquid having a relatively high refractive index, e.g., water, so as to fill a space between the projection system PS and the substrate W. Immersion liquids may also be applied to other spaces in the lithographic apparatus, for example, between the patterning device (e.g. mask) MA and the projection system PS. Immersion techniques can be used to increase the numerical aperture of projection systems. The term "immersion" as used herein does not mean that a structure, such as a substrate, must be submerged in liquid, but rather only means that liquid is located between the projection system PS and the substrate W during exposure.

Referring to FIG. 1, the illuminator IL receives a radiation beam B from a radiation source SO. The source and the lithographic apparatus may be separate entities, for example when the source is an excimer laser. In such cases, the source is not considered to form part of the lithographic apparatus and the radiation beam B is passed from the source SO to the illuminator IL with the aid of a beam delivery system BD comprising, for example, suitable directing mirrors and/or a beam expander. In other cases, the source may be an integral part of the lithographic apparatus, for example when the source is a mercury lamp. The source SO and the illuminator IL, together with the beam delivery system BD if required, may be referred to as a radiation system.

The illuminator IL may comprise an adjuster AD configured to adjust the angular intensity distribution of the radiation beam. Generally, at least an outer radial extent and/or an inner radial extent (commonly referred to as σ -outer and σ -inner, respectively) of the intensity distribution in a pupil plane of the illuminator can be adjusted. IN addition, the illuminator IL may comprise various other components, such as an integrator IN and a condenser CO. The illuminator may be used to condition the radiation beam, to have a desired uniformity and intensity distribution in its cross-section.

The radiation beam B is incident on the patterning device (e.g., mask) MA, which is held on the mask support structure (e.g., mask table) MT and patterned by the patterning device. After passing through the patterning device (e.g. mask) MA, the radiation beam B passes through the projection system PS, which focuses the beam onto a target portion C of the substrate W. With the aid of the second positioner PW and position sensor IF (e.g. an interferometric device, linear encoder or capacitive sensor), the substrate table WT can be moved accurately, e.g. so as to position different target portions C in the path of the radiation beam B. Similarly, the first positioner PM and another position sensor (which is not explicitly depicted in fig. 1) can be used to accurately position the patterning device (e.g. mask) MA with respect to the path of the radiation beam B, e.g. after mechanical retrieval from a mask library, or during a scan. In general, movement of the patterning device support (e.g. mask table) MT may be realized with the aid of a long-stroke module (coarse positioning) and a short-stroke module (fine positioning), which form part of the first positioner PM. Similarly, movement of the substrate table WT or "substrate support" may be realized using a long-stroke module and a short-stroke module, which form part of the second positioner PW. In the case of a stepper (as opposed to a scanner) the patterning device support (e.g. mask table) MT may be connected to a short-stroke actuator only, or may be fixed. Patterning device (e.g. mask) MA and substrate W may be aligned using patterning device alignment marks M1, M2 and substrate alignment marks P1, P2. Although the substrate alignment marks as illustrated occupy dedicated target portions, these substrate alignment marks may be located in spaces between target portions (these are referred to as scribe-lane alignment marks). Similarly, in situations in which more than one die is provided on the patterning device (e.g. mask) MA, the patterning device alignment marks may be located between the dies.

The depicted apparatus may be used in at least one of the following modes:

1. in step mode, the patterning device support (e.g. mask table) MT or "mask support" and the substrate table WT or "substrate support" are kept essentially stationary, while an entire pattern imparted to the radiation beam B is projected onto a target portion C in one go (i.e. a single static exposure). The substrate table WT or "substrate support" is then shifted in the X-direction and/or the Y-direction so that a different target portion C can be exposed. In step mode, the maximum size of the exposure field limits the size of the target portion C imaged in a single static exposure.

2. In scan mode, the patterning device support (e.g. mask table) MT or "mask support" and the substrate table WT or "substrate support" are scanned synchronously while a pattern imparted to the radiation beam B is projected onto a target portion C (i.e. a single dynamic exposure). The velocity and direction of the substrate table WT or "substrate support" relative to the patterning device support (e.g. mask table) MT or "mask support" may be determined by the (de-) magnification and image reversal characteristics of the projection system PS. In scan mode, the maximum size of the exposure field limits the width (in the non-scanning direction) of the target portion in a single dynamic exposure, whereas the length of the scanning motion determines the height (in the scanning direction) of the target portion.

3. In another mode, the patterning device (e.g. mask table) MT or "mask support" is kept essentially stationary, thereby holding a programmable patterning device, and the substrate table WT or "substrate support" is moved or scanned while a pattern imparted to the radiation beam is projected onto a target portion C. In this mode, generally a pulsed radiation source is employed and the programmable patterning device is updated as required after each movement of the substrate table WT or "substrate support" or in between successive radiation pulses during a scan. This mode of operation can be readily applied to maskless lithography that utilizes programmable patterning device, such as a programmable mirror array of a type as referred to above.

Combinations and/or variations on the above described modes of use or entirely different modes of use may also be employed.

As shown in fig. 1, the lithographic apparatus may comprise an in-situ material removal device MRD configured to remove material from one or more support elements of a substrate holder of the lithographic apparatus. The material removal device MRD is configured to remove material from one or more support elements of the substrate holder in order to obtain a more uniform support for the substrate W supported on the substrate holder. The material removal device MRD may be located at a substantially stationary site and comprises a material removal tool MRT to be brought into contact with the one or more support elements for removing material of the one or more support elements.

The lithographic apparatus may further comprise a detector HDD configured to detect a height deviation of the support element affecting the flatness of the surface of the substrate W supported on the substrate holder. The detector HDD may be, for example, a level sensor configured to measure the upper surface of the substrate W supported on the substrate holder. Such a level sensor is disclosed, for example, in U.S. patent No. 5,191,200, which is incorporated herein by reference in its entirety. The detector HDD can be used to measure the top surface of multiple substrates to determine which errors in the surface are caused by the substrates themselves and which are caused by the substrate supports (i.e., support elements).

The detector HDD may be connected to a controller MRC which is coupled between the detector HDD and the material removal device MRD. The controller may be configured to control the material removal device MRD to adjust the height of the support element corresponding to the detected height deviation of the protrusions 4 affecting the surface flatness of the substrate. The controller MRC may be a separate controller particularly adapted for creating a flat surface by removing material of the support elements of the substrate holder when needed, or it may be integrated in a controller configured to perform a plurality of control tasks in the lithographic apparatus.

Further details regarding the general operation of the material removal device MRD are disclosed in US2005/0061995A1, which is incorporated herein by reference in its entirety.

In general, the removal of material from one or more support elements may be carried out by a relative movement between the material removal tool MRT and the one or more support elements. The relative movement may be performed by translating the one or more support elements relative to the material removal tool MRT and/or translating the material removal tool MRT relative to the one or more support elements. The material removal tool MRT may be rotated to enhance the removal of material of the support element.

Embodiments of the present invention provide a tool that can be used to modify a substrate holder to improve the flatness of the support elements of the substrate holder. The tool may correspond to the material removal tool MRT as described above. In other cases, the tool may refer to a height adjustment tool.

The invention provides a tool for modifying a substrate holder. The tool may more specifically be used to modify a substrate support element of a substrate holder. In other cases, the support elements may be referred to as nubs. An example of the tool 1 is shown in fig. 2A to 2C. Fig. 2A shows a surface of the tool 1 for contacting a substrate holder, fig. 2B shows a perspective view of the tool 1, and fig. 2C shows a cross-sectional view through X-X of fig. 2A. The surface of the tool 1 shown in fig. 2A may be referred to as the base of the tool 1. This is because the tool 1 is generally arranged with the surface facing downwards towards the substrate W as shown in figure 2A when in use.

Fig. 3 shows an example of a substrate holder 20 with a support element 21, wherein the tool 1 may be used to modify the support element 21 of the substrate holder 20. In other words, the tool 1 may be used to remove material from the support element 21. This may alter the overall height of the at least one support element 21 and/or alter the roughness of the at least one support element 21. As shown in fig. 3, the support element 21 has a support surface 22. The support surface 22 is used to contact the underside of the substrate W. Ideally, the combined support surface 22 provides a flat plane that can support the substrate W as described above. This allows the substrate W to be relatively flat when irradiated to reduce errors.

The tool 1 may optionally be part of a material removal device MRD as shown in fig. 3. The material removal device MRD may comprise a tool support 10 as shown in fig. 3. The tool support 10 may be configured to secure the tool 1. The tool support 10 may provide a connection between the tool 1 and the rest of the lithographic apparatus.

Fig. 3 shows a portion of a substrate holder 20 of a lithographic apparatus. The substrate holder 20 may be part of a substrate support configured to support the substrate W during projection of an image on the substrate W. The substrate holder 20 may be provided on the substrate table WT. For example, the substrate holder 20 may be held on the substrate table WT using a vacuum system (not shown).

The substrate holder 20 is configured such that the surface of a substrate W supported on the substrate holder 20 lies in a predefined plane with respect to the propagation direction of the projection beam B. The surface is preferably oriented transverse to the direction of propagation of the projection beam B. The substrate holder 20 has a support surface 23 and a plurality of support members 21 extending from the support surface 23 to support the substrate W on the support members 21. The configuration of the plurality of support elements 21 is designed to obtain an optimal support of the substrate W supported thereon. A part of the substrate holder 20 is shown in cross-section in fig. 3, whereby some support elements 21 are located in the plane of the cross-section and some support elements 21 are located behind this plane.

As described, the substrate holder 20 may not provide a flat support surface for the substrate W for a variety of reasons. The substrate holder 20 may deteriorate over time due to wear from the interaction of the support elements 21 with the respective substrates. Wear of the support elements 21 results in a change in height of the support elements across the substrate holder 20.

When friction between the substrate W and the substrate holder 20 is positioned on the substrate holder 20, the friction contributes to the shape of the substrate W. This friction varies over time due to contamination and smoothing of the support element 21 due to wear. This situation may cause the roughness and height of the support element 21 to vary over the lifetime of the substrate holder 20. Current correction methods (alignment, APC, baseline scriber) do not completely limit the impact on overlay error, which may result in reduced yield of patterned substrates. As the support member 21 is worn, which may increase the contact area between the substrate W and the substrate holder 20, friction may change.

The larger contact area generates more van der waals forces, which causes the substrate to "stick" to the substrate holder 20. Providing a preferred roughness on the support surface of the support element 21 may reduce the overall contact area and help reduce or avoid such sticking.

Generally, the support surface 21, which is used to contact the underside of the substrate W, has a desired level of roughness. If the roughness of the support surface is too low, this situation may result in increased friction of the substrate holder, which may lead to sticking and overlay errors. It is therefore beneficial to reduce friction by increasing the roughness of the support surface of the support element. Therefore, it is preferable to maintain the roughness at a desired level.

The roughness of the support surface is typically on the order of nanometers. In other words, the support surface 22 of the support element 21 generally has a structure in the order of a few nanometers or a few tens of nanometers. For example, the substrate table WT may have a contact roughness of at least 12 nm. Atomic Force Microscopy (AFM) can be used to characterize contact roughness. Additionally or alternatively, a white light interferometer may be used to measure roughness. White light measurements can roughly match Atomic Force Microscope (AFM) measurements. If the contact roughness is below about 12nm, van der Waals bonding may generally increase the contact pressure and effectively increase friction.

When positioned on the substrate holder 20, the substrate W will rest on top of the peak structures of each of the support surfaces 22. Therefore, the flatness of the entire substrate holder 20 can be improved by reducing the peak of the roughness on the support surface 22 having a higher peak than the other support surfaces 22.

The roughness of the support surface 22 can be determined by observing where the contact pads contact the support element. The amount of surface area of the contact pad contacting the support surface 21 of one support member 20 is indicative of the roughness of the support member 20.

The tool 1 may be used to modify the substrate holder 20 to remove material. In other cases, this may be referred to as polishing. The material and roughness of the tool 1 may be selected such that the resulting roughness and adhesion of the substrate W on the substrate holder 20 are maintained at an optimum level. The tool 1 may be used periodically (possibly daily), which may reduce or avoid system drift. Ideally, the roughness of the tool 1 will enable flatness of the support surface, a desired roughness and improved van der waals forces. In other cases, the tool 1 may refer to a puck and/or a flawless stone.

The tool 1 can be brought into contact with the support element 21 and can be moved relative to the support element 21 to modify the support surface 22. Thus, the tool 1 may be used to scrape the support surface 22 to modify the roughness of the support surface, which affects the friction between the support surface 22 and the substrate W. Additionally or alternatively, the tool 1 may be used to wear at least one of the support surfaces 22 in order to wear the at least one support surface 22 to flatten the overall support plane provided by the support surface 22. The tool 1 may be used to make the substrate table WT flatter while also achieving a desired level of roughness. It may be beneficial to use a tool 1 that improves flatness without affecting roughness (possibly at a preferred level). Alternatively, it may be beneficial to use a tool 1 that improves roughness without affecting flatness (possibly at a preferred level). Modifying the support surface 22 may generally refer to altering the flatness and/or roughness of the support surface 22.

Multiple tools may be used. For example, a first tool may be used to generally improve the flatness of the substrate table WT without affecting the roughness too much, and a second tool may be used to generate a preferred roughness without affecting the overall flatness too much (or vice versa). For example, the first and second tools may have different configurations (i.e. protrusions arranged in different formations) that are more suitable for affecting the flatness and/or roughness of the substrate table WT. Using two tools may be beneficial because it provides greater design freedom to optimize both tools.

The design of the projections 4 on the tool 1 may alter the way in which the tool 1 affects the roughness and flatness of the substrate table WT. Thus, for example, the spacing (i.e. frequency) of the protrusions 4 on the tool 1 may alter the effect of the tool 1 on the substrate table WT. The influence of the tool 1 on the roughness and/or flatness of the substrate table WT may additionally depend on other parameters, such as the cross-sectional area of the protrusions 4, the roughness of the tool 1 and/or the weight of the tool 1.

A tool 1 with a low spatial frequency may have well-spaced protrusions with a distance between the protrusions 4 of more than about 32 mm. A low spatial frequency tool may have minimal or no effect on local flatness or roughness, but may be used to alter global substrate table WT flatness.

A tool with medium spatial frequency may have a distance between the projections 4 that is less than about 32mm and greater than the distance between the support elements 21 (e.g., greater than about 1.5-2.5 mm). A medium spatial frequency tool may improve the flatness of the substrate table WT but may have minimal to no effect on the roughness of the substrate table WT. This type of tool may not have a beneficial effect on the flatness of the substrate table WT around the edge of the substrate table WT.

The high spatial frequency tool may have a distance between the projections 4 that is less than the distance between the support elements 21 and the projections 4, for example less than about 1.5-2.5 mm. Preferably, the distance between the protrusions 4 on the high spatial frequency tool is smaller than the diameter of the support element 21, for example preferably smaller than or equal to about 210 and 350 μm. A high spatial frequency tool may be beneficial to improve the roughness of the substrate table WT. High spatial frequency tools may not have a beneficial effect on the flatness of the substrate table.

Alternatively, both functions may be provided by the same tool. For example, the support element 21 may be modified using a tool having a medium to high spatial frequency to improve the roughness and flatness of the substrate table WT. The distance between the protrusions may be selected depending on the desired effect on roughness and flatness. Efficiency may be improved using only one tool.

When the tool 1 is moved over the support element 21 (to modify the substrate holder 20), the tool 1 will generally hit the highest raised peak of the support surface 22 and reduce the size of the peak. This reduces the overall higher peaks and improves the overall flatness of the combined support surface 22.

As shown in fig. 2A, 2B and 2C, the tool 1 comprises a body 2 having a body surface 3. The tool 1 comprises a plurality of protrusions 4 from a body surface 3. In other words, a plurality of projections 4 extend from the main body 2. The plurality of projections 4 have distal ends 5 configured to contact the support surface 22 to modify the substrate support member 21. In other cases, the protrusion 4 may refer to an island or a pad. The distal end 5 is the end surface of the plurality of protrusions that is furthest from the body surface 3.

During wear and modification of the substrate support member 21, debris may be generated. Debris refers generally to any contaminating material, but specifically refers to any material removed from the substrate support member 21 and from the tool 1 itself. Debris can affect the roughness and overall flatness of the substrate holder 20.

An advantage of having a plurality of protrusions 4 is that there are gaps between the protrusions 4 which allow debris to be collected and possibly pushed into the gaps between the substrate support elements 21. Additionally, the plurality of projections 4 create a storage space for debris within the tool 1 itself, thereby allowing debris to accumulate in the gaps between the plurality of projections 4. For both reasons, debris is less likely to remain on top of the support surface 22 of the substrate support member 21. This reduces or prevents contamination on the support surface 22. Additionally, having a plurality of protrusions 4 means that an increased number of edges contact the substrate table WT surface, which may be more effective in creating substrate table WT roughness.

Additionally, the provision of a plurality of protrusions 4 means that the surface area of the tool 1 in contact with the substrate holder 20 can be controlled to average out the smaller spatial frequencies in the overall flatness of the substrate holder 20.

Additionally, the provision of a plurality of projections 4 means that, in use, a smaller area of the tool 1 is in contact with the substrate holder 20. This allows scratching to occur to provide the desired level of roughness to the support surface, thereby improving the "sticking" problem.

As will be seen in the figures, the tool 1 may be generally in the shape of a circular disc or puck. In other words, the body 2 may be plate-shaped. Accordingly, the body 2 may be formed as a circular object having a relatively thin thickness. For example, the tool 1 may be of the order of a few millimeters thick or a few tens of millimeters thick. For exemplary purposes only, the tool 1 may have a thickness of about 1-10mm thick or preferably about 2-6mm thick.

The tool 1 should have general dimensions that can be used to modify the support surface 22 of the support element 21. The diameter of the tool 1 is therefore typically of the order of a few tens of millimetres. Ideally, the tool 1 should be large enough not to fall into any gaps between the substrate support members 21.

The diameter of the tool 1 is indicated by the distance L in fig. 2C. The diameter L of the body 2 may be less than or equal to about 50 mm. The diameter L of the body 2 may be less than or equal to about 35mm or more preferably about 32 mm. In general, it is advantageous to have a tool 1 of less than or equal to about 50mm, or preferably less than or equal to about 35mm, since this allows more careful control of the modifications made to the support surface 22. The tool 1 will generally begin to filter any contents that are smaller than its own size. Therefore, it is generally advantageous that the diameter of the tool 1 is larger than the exposure slit size of the lithographic apparatus, which is typically about 28 mm. In general, it is advantageous to make the tool 1 as large as possible, since the tool 1 can be used at any time for modifying a large number of substrate support elements 21, and thus the effective use of the tool 1 is improved. Thus, the diameter of the body 2 of the tool 1 may be greater than 50 mm.

The tool 1 may not comprise a through hole. In other words, the tool 1 may not comprise a hole through the body 2, i.e. the tool 1 may not comprise a hole or cavity from the body surface 3 to the opposite surface of the body 2. It may be advantageous to avoid having through holes in the tool 1 to make the manufacturing process of the tool 1 simpler and easier.

The tool 1 may not have an overall annular shape. The tool 1 may not comprise, for example, only one recess substantially in the center of the tool 1. The tool 1 may not be shaped to provide an annular surface for contacting the substrate holder 20. It may be advantageous to avoid having these shapes (e.g. annular or having a single recess) to make the manufacturing process of the tool 1 simpler and easier.

Providing a tool 1 without through holes and/or recesses may be advantageous, since the tool 1 may be used to modify a large number of substrate support elements 21 at a time, and thus the effect of the tool 1 may be greater. This may be the case because the area of the tool 1 in contact with the substrate support member 21 is increased at any time.

Preferably, the main body surface 3 is substantially flat. This situation means that the body surface 3 ideally has only a small variation along the surface. Thus, preferably, the main body surface 3 is arranged substantially in one plane. The surface may have a certain amount of roughness. Generally, the portion of the tool 1 that contacts the substrate support member 21 is the distal end 5 of the tool 1. Thus, the specific roughness of the body surface 3 may not be controllable to the same extent as the distal ends 5 of the plurality of projections 4.

The plurality of projections 4 and the main body 2 may be provided integrally with each other. Thus, for example, the body 2 and the plurality of projections 4 may be formed from a single piece of material. Alternatively, a plurality of protrusions 4 may be provided on the body 2 by attaching the protrusions 4 to the body surface 3, for example, with an adhesive.

The tool 1 may be made of a variety of materials. Preferably, the hardness of the tool 1, and in particular the material forming the distal end 5, is the same or higher than the hardness of the support surface 22 of the substrate holder 20. Advantageously, if the tool 1 and in particular the distal end 5 is harder than the support surface 22, the interaction between the tool 1 and the support surface 22 will wear the substrate holder 20 instead of the tool 1. Advantageously, if the hardness of the tool 1 and in particular of the distal end 5 is similar to that of the support surface 22, this may result in a high roughness of the support surface 22 due to the interaction between the tool 1 and the support surface 22.

Preferably, the tool 1 is made of a relatively hard and tough material. The tool 1 may comprise carbon reinforced silicon carbide (CSiC), siliconized silicon carbide (SiSiC), silicon carbide (SiC), alumina (Al)₂O₃) And/or diamond-like carbon (DLC). The tool 1 may be formed from a single piece of material. Thus, the entire tool 1 may be formed from one of these materials. Alternatively, the tool 1 may be formed of a combination of materials including at least one of these materials. In particular, since the distal end 5 of the tool 1 is the portion of the tool 1 arranged to be in contact with the substrate support element 21, in particular, the material selected for the plurality of protrusions 4 may be at least one of: carbon enhanced silicon carbide, aluminum oxide, and/or diamond-like carbon. Additionally or alternatively, the tool 1 may have a layer or coating on the distal end 5 formed of at least one of these materials.

Preferably, the plurality of protrusions 4 have a height h of between about 50 nanometers and 1 mm. More preferably, the plurality of protrusions 4 have a height of about 1 μm. The height h of the protrusion 4 is considered to be the distance from the main body surface 3 to the distal end 5 of one of the plurality of protrusions 4, as shown in fig. 2C. The height h may vary and it will be appreciated that the height h of the plurality of projections 4 may slowly wear away slightly over time. However, the protrusion 4 is at a distance from the main body surface 3 to ensure that the distal end 5 of the protrusion 4, rather than the main body surface 3, contacts the support surface 22 is preferred.

The number of projections 4 on a single tool 1 may vary. Preferably, the number of projections 4 is greater than or equal to 20. Preferably, the number of projections 4 is less than or equal to 50. The number may vary and may be less than 20 or greater than 50. Desirably, the number of projections 4 is about 20-30. Providing at least three protrusions 4 may reduce or prevent tilting of the tool 1 on the surface of the substrate table WT.

Preferably, at least one of the plurality of protrusions 4 has a thickness greater than or equal to about 9mm²Or more preferably greater than or equal to about 20mm²Cross-sectional area of (a). Preferably, the cross-sectional area of the plurality of projections 4 is the same as the area of the distal ends 5 of the plurality of projections 4. Thus, the cross-sectional area describes the area of the plurality of protrusions 4 that may be in contact with the support surface 22. It is preferable that the area of the plurality of projections 4 is larger than the pitch size of the substrate support member 21. By way of example only, an approximately 32mm tool 1 may cover approximately 130 substrate support elements 21 with a pitch dimension between the support elements of approximately 2.5mm, or approximately 360 substrate support elements 21 with a pitch dimension of approximately 1.5 mm. The preferred total number of protrusions may be about half the number of substrate support members 21 covered. Thus, in these examples, the total number of protrusions is 65 or 180. The preferred number of projections 4 may be up to 180, but there may be more projections 4.

The total area of the plurality of protrusions 4 may be optimized to ensure that a certain pressure is applied to the substrate holder 20 through each protrusion of the plurality of protrusions 4. Preferably, 10% or more of the surface area of the tool 1 is formed with protrusions. If the projection 4 is formed to be larger than 10% of the surface area of the tool 1, the interaction with the substrate table WT may be increased and, thus, the effectiveness of the tool 1 may be increased. The width of the plurality of protrusions 4 may be selected to be greater than the distance between adjacent substrate support elements 21 in order to maintain contact between the distal end 5 of the tool 1 and the support surface 22.

The plurality of projections 4 shown in the various figures are shown generally as squares. Thus, the distal end 5 is shown generally as a square. However, this is not necessarily the case. The plurality of projections 4 may be provided in any shape. For example, the plurality of protrusions 4 may have a circular cross-sectional area or a triangular cross-sectional area. Other more complex shapes may be used. The shape of the plurality of projections 4 may be selected to improve debris removal and thus reduce contamination. However, having a simple shape (such as square, triangular or circular) would be easier to manufacture. The plurality of projections 4 may be uniform in that they all have similar heights and/or shapes. Alternatively, at least one protrusion of the plurality of protrusions 4 may differ in height and/or shape from the other plurality of protrusions 4.

Preferably, the pitch between adjacent projections 4 is greater than or equal to about 5mm, or preferably greater than or equal to about 7mm, or preferably greater than or equal to about 12 mm. As will be appreciated, the pitch between adjacent projections 4 may vary depending on the type of pattern provided. For example, the patterns in fig. 4A to 4C each have an equal pitch provided between adjacent protrusions 4. However, as shown in fig. 2A to 2C, this may not be the case. The pitch may be the distance from the center of one protrusion to the center of the adjacent protrusion 4. Furthermore, the pitch may be determined by the distance between the center of one projection 4 and the nearest center of another nearest projection 4. Thus, the pitch may refer to the minimum distance between the protrusions 4.

The size, shape and/or pitch of the projections 4 may be selected to optimize the effect of the tool 1 on the substrate holder 20. Ideally, at least about 10-15 support surfaces are in contact with the tool 1 at any one time (during use) to ensure uniform contact of the tool 1 with the substrate holder 20.

The plurality of protrusions 4 on the body surface 3 may be provided in a variety of different patterns. Examples of these patterns are shown in fig. 2A to 2C and 4A to 4C, as will be described below. As shown in these figures, the plurality of protrusions 4 may be provided in a uniform pattern. Although various patterns are shown, the protrusions 4 need not be provided in a pattern, and a plurality of protrusions 4 may be provided without a clearly identifiable pattern.

The patterns shown in fig. 2A to 2C have a protrusion at the center of the main body surface 3, wherein the additional protrusions 4 are arranged along a radially outward line. An alternative pattern is depicted in fig. 4A to C, where the rows and columns of protrusions 4 are provided with a uniform distance between each row and column. Another alternative pattern is depicted in fig. 7A and 7B, wherein the protrusions 4 have an elongated shape in the radial, respectively circular direction. It is understood that other different types of patterns may be used.

Optionally, at least one of the plurality of protrusions 4 may comprise a plurality of protrusions 6, as shown in fig. 5. The protrusion 6 is an additional extension on any one of the protrusions 4. Thus, any one of the plurality of protrusions 4 including the protrusion 6 has a distal end 5 at a point farthest from the main body surface 3 (i.e., at an end of the protrusion 6). This means that the distal end 5 of the projection 4 is formed on the end of the protrusion 6. As will be seen, this generally means that the projections 4 have smaller protrusions 6 extending from the intermediate surface 7. When no protrusion 6 is provided, the intermediate surface 7 may correspond to the distal end of the protrusion 4. As shown in fig. 5, a protrusion 6 may be provided on each of the protrusions 4.

The distance d between adjacent protrusions 6 may typically be between about 50 nanometers and 1 mm. The plurality of protrusions 6 may extend between about 50 nanometers to 1 mm. In other words, the protrusion 6 may have a height of about 50nm to 1mm from the start of the protrusion to the end of the protrusion 6.

The protrusions 6 may form thin lines. The thread may be linear or wavy or curved.

The plurality of protrusions 6 and the protruding portion 4 may be provided integrally with each other. Thus, for example, the protrusion 6 and the projection 4 may be formed from a single piece of material. Alternatively, the protrusion 6 may be provided on the protrusion 4 by attaching the protrusion 4 to the surface of the protrusion 4 by, for example, an adhesive.

Providing protrusions 6 as described may be particularly useful for capturing debris between protrusions 6 to reduce contamination of substrate holder 20. Additionally, the protrusion 6 allows the contact area of the tool 1 to be optimized and, thus, the pressure under the tool 1 may be increased, which may be beneficial for controlling the roughness of the support surface 22.

Alternatively, a plurality of projections 4 may be provided in a similar manner to the projections 6. In other words, the plurality of protrusions 4 may be provided in a shape that is much smaller than the shape described above with respect to fig. 2, 3, and 4. For example, the distance x between adjacent protrusions of the plurality of protrusions 4 may be between about 50 nanometers and 1 mm. Thus, in this way, the projections 4 may generally be used to form grooves in the surface of the tool 1. An example of this is shown in fig. 6.

The projections 4 may form thin lines. The thread may be linear or wavy or curved.

In this case, the height of the protrusion 4 may be between about 50 nanometers and 1 mm. In other words, the distance between the distal end 5 of the protrusion 4 and the body surface 3 is between about 50 nanometers and 1 mm. It may be advantageous when a small amount of debris is trapped in the grooves formed between the plurality of projections 4.

Providing a plurality of protrusions 4 having these dimensions may be particularly beneficial for capturing debris between the plurality of protrusions 4 to reduce contamination of the substrate holder 20. Additionally, having a plurality of protrusions 4 of these dimensions allows the contact area of the tool 1 to be optimized and, therefore, the pressure under the tool 1 may be increased, which may be beneficial to control the roughness of the support surface 22.

The rear surface 8 of the tool 1 may be provided in various shapes to make it easier and/or more secure that the tool 1 is held in place. The tool 1 may be connected or connectable to a tool support 10. The rear surface 8 of the tool 1 may comprise at least one indentation (index) to cooperate with the tool support 10. The rear surface 8 of the tool 1 is a surface that is not used to modify the substrate holder 20. The diameter of the rear surface 8 of the tool 1 may be smaller than the diameter of the body surface 3, for example, to improve the connection between the tool 1 and the tool support 10.

It may be preferred that the tool 1 remains substantially flat relative to the substrate holder 20 during use. In other words, it may be preferred to have the body surface 3 of the tool 1 substantially parallel to the substrate holder 20. However, this is not necessary, and variations in the orientation of the tool 1 may allow the uneven support surface 22 to be worn or flattened more effectively. The tool 1 may be connected to the tool support 10 in a manner allowing for orientation changes, for example by using a ball and socket type connection.

The tool 1 may be part of a larger system comprising a plurality of tools 1 s. The plurality of tools 1s may have the same or similar plurality of projections 4 and/or protrusions 6. At least one of the tools 1s may be different from the other tools 1 s.

The tool 1 may be used across the entire substrate holder 20. In other words, the tool 1 may be used to contact each support element 21 at least once.

The tool 1 described above may be used to provide a method. More specifically, the method may be used to modify the substrate support element 21 of the substrate holder 20. The substrate support member 21 has a support surface 22 for supporting the substrate W. The method may comprise providing a tool 1 as described above. The method may further comprise bringing at least some of the support surfaces 22 of the substrate holder 20 into contact with the distal ends 5 of the protrusions 4 of the tool 1, and modifying the support surfaces 22 using the tool 1.

The substrate holder 20 may be moved along the tool 1 in order to remove material from the top of the substrate support member 21 contacted by the tool 1. Alternatively, the tool 1 may be moved relative to the substrate holder 20, for example while the substrate holder 20 is held stationary. For example, the material removal device MRD may be configured to move the tool 1 over the substrate support element 21 while the substrate holder 20 is not moved. Alternatively, the substrate holder 20 and the tool 1 may be moved simultaneously.

To improve the removal of material, the tool 1 may be rotated about an axis (relative to the substrate holder) parallel to the z-direction shown in fig. 3. However, this may not be required to obtain the desired modifications to the substrate holder 20.

The pressure in the z-direction between the tool 1 and the substrate support element 21, which pressure is used to obtain the abrasive effect, may be applied by the substrate holder 20 or the tool 1 (or more specifically the material removal device MRD) or by both. Preferably, the use of the tool 1 should be accurately controlled, since this situation may have a negative effect on the flatness of the substrate holder 20 if the force imparted by the tool 1 is too great.

The tool 1 may be used in various ways. For example, the tool 1 may be used to modify the entire substrate holder 20, i.e. across the entire substrate holder 20 in one setting. Alternatively, the tool 1 may be used to modify a local area, i.e. a part of the entire substrate holder 20. The frequency of use of the tool 1 may vary. For example, the local cleaning of a particular portion of the substrate holder 20 may be performed several times per day (e.g., 4-5 times per day). Greater cleaning of the entire substrate holder 20 may be performed less frequently (e.g., daily or weekly). For example, the frequency and type of modification may be determined based on measurements taken indicative of the flatness of the substrate W and/or substrate holder 20. The flatness of the substrate holder 20 is considered to be the flatness of the support surface 22 on which the substrate W is positioned.

A lithographic apparatus may be provided comprising a tool 1 as described above. The lithographic apparatus may be configured to modify the substrate support element 21 of the substrate holder 20 using the tool 1. The lithographic apparatus may comprise a substrate holder 20 having a plurality of support elements configured to support a substrate.

The lithographic apparatus comprising the tool 1 may be all or part of the lithographic apparatus described above with respect to fig. 1. The lithographic apparatus comprising the tool 1 may be at least part of a metrology device and/or an inspection device (e-beam). The lithographic apparatus comprising the tool 1 may be used in combination with the lithographic apparatus described in fig. 1. A lithographic apparatus comprising the tool 1 may more generally refer to an apparatus configured to modify a substrate support element 21 of a substrate holder.

The lithographic apparatus comprising the tool 1 may further comprise a detector configured to detect a height deviation of one or more of the support elements that affect the surface flatness of a substrate supported on the substrate holder. The detector may correspond to the detector HDD described previously. The tool 1 may be configured to modify the height of one or more support elements corresponding to the detected height deviation of the support elements.

A corresponding method may be provided using a lithographic apparatus.

In the above, the use of the tool 1 is described as being for removing material of one or more substrate support elements 21 supporting a holder to provide a more uniform support for a substrate support thereon. Similar tools 1 may also be used for other article support systems, such as patterning device supports. Thus, the tool 1 may be used more generally for contacting a support surface. For example, in an embodiment, a lithographic apparatus is provided. In this embodiment, the lithographic apparatus is configured to modify a support element of the article holder. The lithographic apparatus comprises an article holder having a plurality of support elements having a support surface configured to support the article. The lithographic apparatus further comprises a material removal device comprising a tool 1 comprising a body 2 having a body surface 3, wherein the tool 1 comprises a plurality of protrusions 4 from the body surface 3, the plurality of protrusions 4 having distal ends configured to contact the support surface to modify the support element.

The lithographic apparatus comprising the tool 1 may be all or part of the lithographic apparatus described above with respect to fig. 1. The lithographic apparatus comprising the tool 1 may be at least part of a metrology device and/or an inspection device (e-beam). The lithographic apparatus comprising the tool 1 may be used in combination with the lithographic apparatus described in fig. 1. A lithographic apparatus comprising the tool 1 may more generally refer to an apparatus configured to modify a support element of an article holder.

In this embodiment, the lithographic apparatus comprising the tool 1 may further comprise a detector configured to detect a height deviation of one or more of the support elements that affect the surface flatness of an article supported on the article holder. The detector may correspond to the detector HDD described previously. The detector may be similar to the detector HDD, but may be used to detect the surface flatness of the article rather than the substrate. The tool 1 may be configured to modify the height of one or more support elements corresponding to the detected height deviation of the support elements.

A corresponding method for modifying a support element of an article holder, the support element having a support surface for supporting an article, may be provided. The method comprises the following steps: providing a lithographic apparatus according to this embodiment; at least some of the support surfaces are brought into contact with the distal ends of the projections of the tool, and the tool is used to modify the support surfaces.

The tool used to modify the article in this embodiment may have any or all of the variations described above for the tool 1 specifically used to modify the substrate holder 20.

Providing a tool 1 according to an embodiment of the invention in a lithographic apparatus provides many advantages over prior art lithographic apparatus. A first advantage is that the substrate table/holder (or other support surface) can be mounted in the lithographic apparatus with less flatness and therefore at lower cost, since the substrate holder can be planarized in the lithographic apparatus by using the tool 1. Further, since unevenness due to abrasion can be corrected, abrasion of the substrate holder is no longer of great significance. Therefore, less stringent constraints on the wafer stage/substrate holder 20 material may be used. Furthermore, by using the tool 1, the flatness of the support surface 22 may be improved over time, thereby improving the overlay performance of the lithographic apparatus.

Although specific reference may be made in this text to the use of lithographic apparatus in the manufacture of ICs, it should be understood that the lithographic apparatus described herein may have other applications, such as 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. Those skilled in the art will appreciate that, in the context of such alternative applications, any use of the terms "wafer" or "die" herein should be considered as synonymous with the more general terms "substrate" or "target portion", respectively. The substrate referred to herein may be processed, before or after exposure, in for example a track (a tool that typically applies a layer of resist to a substrate and develops the exposed resist), a metrology tool and/or an inspection tool. Where applicable, the disclosure herein may be applied to such and other substrate processing tools 1 s. Further, the substrate may be processed more than once, for example in order to create a multi-layer IC, so that the term substrate used herein may also refer to a substrate that already contains multiple processed layers.

Although specific reference may have been made above to the use of embodiments of the invention in the context of optical lithography, it will be appreciated that the invention may be used in other applications, for example imprint lithography, and where the context allows, is not limited to optical lithography. In imprint lithography, a topography in a patterning device defines the pattern created on a substrate. The topography of the patterning device may be pressed into a layer of resist supplied to the substrate, the resist being subsequently cured by the application of electromagnetic radiation, heat, pressure or a combination thereof. The patterning device is removed from the resist leaving a pattern in it after the resist is cured.

The terms "radiation" and "beam" used herein encompass all types of electromagnetic radiation, including Ultraviolet (UV) radiation (e.g. having a wavelength of or about 365, 248, 193, 157 or 126 nm) and extreme ultra-violet (EUV) radiation (e.g. having a wavelength in the range of 5-20 nm), as well as particle beams, such as ion beams or electron beams.

The term "lens", where the context allows, may refer to any one or combination of various types of optical components, including refractive, reflective, magnetic, electromagnetic and electrostatic optical components.

While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. The above description is intended to be illustrative, and not restrictive. Thus, it will be apparent to one skilled in the art that modifications may be made to the invention as described without departing from the scope of the claims set out below.

The above description is intended to be illustrative, and not restrictive. Thus, it will be apparent to one skilled in the art that modifications may be made to the invention as described without departing from the scope of the claims set out below.