WO2022200267A1

WO2022200267A1 - Tool for modifying a support surface

Info

Publication number: WO2022200267A1
Application number: PCT/EP2022/057339
Authority: WO
Inventors: Matthew Stephen Beaton MOLITERNO; Peter Conrad KOCHERSPERGER
Original assignee: Asml Holding N.V.
Priority date: 2021-03-24
Filing date: 2022-03-21
Publication date: 2022-09-29
Also published as: JP2024511313A; KR20230158515A; CN117063127A

Abstract

Devices and methods are disclosed for modifying substrate support elements of a substrate holder. According to some embodiments, device is disclosed, the device including a substrate holder having a plurality of support elements protruding from a first side of the substrate holder, a support structure configured to hold the substrate holder in a transverse manner from a second side of the substrate holder, and a cleaning tool having a spherical main body. The device also includes a processor that aligns a predetermined region of interest of the substrate holder with a predetermined location of the cleaning tool, manipulates movement of the support structure such that the alignment produces a contact between the predetermined region of interest and the predetermined location, and initiates a cleaning operation of the predetermined region of interest.

Description

TOOL FOR MODIFYING A SUPPORT SURFACE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority of U.S. Provisional Patent Application Number

63/165,327, which was filed on March 24, 2021, and which is incorporated herein in its entirety by reference.

FIELD

[0002] The present disclosure relates to tools for modifying a holder, methods for modifying a holder using the tool, and lithographic apparatus comprising the tool.

BACKGROUND

[0003] A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such a case, a patterning device, which is alternatively referred to as a mask or a reticle, can be used to generate a circuit pattern to be formed on an individual layer of the IC. This pattern can be transferred onto a target portion (e.g. including part of, one, or several dies) on a substrate (e.g. a silicon wafer). Transfer of the pattern is typically via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate. In general, 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 once, and so-called scanners, in which each target portion is irradiated by scanning the pattern through a radiation beam in a given direction (the “scanning” direction) while synchronously scanning the substrate parallel or anti parallel to this direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.

[0004] There is a continuing desire to manufacture devices, e.g. integrated circuits, with ever smaller features. Integrated circuits and other microscale devices are often manufactured using optical lithography, but other manufacturing techniques, such as imprint lithography, e-beam lithography and nano scale self-assembly are known.

[0005] During manufacturing, a device is irradiated. It is important to ensure that the irradiation process is as accurate as possible. One of the issues with making the irradiation processes as accurate as possible is ensuring that the device to be irradiated is in the correct position. In order to control the position of the device, a substrate holder can be used. Generally, a substrate will be supported by the substrate holder whilst the substrate is being irradiated. When the substrate is positioned on the substrate holder, friction between the substrate and the substrate holder can prevent the substrate from flattening out over a surface of the substrate holder. To address this issue, the substrate holder can be provided with support elements that minimize the contact area between the substrate and the substrate holder. The support elements on the surface of the substrate holder can otherwise be referred to as burls or protrusions. 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 elements reduce the contact area between the substrate holder and the substrate, thus reducing friction, and allowing the substrate to move to a flatter position on the substrate holder.

[0006] The support elements generally extend substantially perpendicularly from a surface of the substrate holder. In operation, the backside of the substrate is supported on the support elements, at a small distance from the main body surface of the substrate holder, in a position substantially perpendicular to the direction of propagation of the projection beam. Thus, the tops of the support elements (i.e. support surfaces), rather than the main body surface of the substrate holder, define an effective support surface for the substrate.

[0007] Known tools and methods can still be improved to provide support elements with improved flatness. Additional or alternative methods and tools can be desirable to achieve a preferred flatness in a different way. Furthermore, it is beneficial to achieve this flatness whilst also providing a desired level of roughness on the support elements to provide some friction between the support elements and the substrate.

SUMMARY

[0008] It is desirable for cost of ownership, cost of goods and/or quality of overlay to provide an improved height adjustment tool for use in a lithographic apparatus, or at least an alternative therefor. Furthermore, it is desirable to provide a method for use of such improved or alternative height adjustment tool and a lithographic apparatus comprising such an improved or alternative height adjustment tool. [0009] According to some embodiments, there is described a device for modifying substrate support elements of a substrate holder, the device includes a substrate holder having a plurality of support elements protruding from a first side of the substrate holder. The device also includes a support structure configured to hold the substrate holder in a transverse manner from a second side of the substrate holder. The device also includes a cleaning tool having a spherical main body; and a processor that aligns a predetermined region of interest of the substrate holder with a predetermined location of the cleaning tool, manipulates movement of the support structure such that the alignment produces a contact between the predetermined region of interest and the predetermined location, and initiates a cleaning operation of the predetermined region of interest. [0010] According to some embodiments, the predetermined region of interest includes one or more support elements and/or one support element having a support surface. According to some embodiments, the contact produced between the predetermined region of interest and the predetermined location includes a contact between the support surface and the predetermined location of the cleaning tool. According to some embodiments, the device includes a detector that measures physical parameters of the support surface. The physical parameters may include a degree of roughness of the support surface. Furthermore, the physical parameters can include a height deviation measurement of one or more support elements of the substrate holder, the height deviation measurement being a detected height deviation from a predetermined degree of surface flatness of the substrate holder. According to some embodiments, the processor controls the cleaning operation to modify a height of the support element corresponding to the detected height deviation of the support element.

[0011] According to some embodiments, the processor also controls the alignment to lower and tilt the support structure to align the predetermined region of interest with the predetermined location. According to some embodiments, the processor further controls the performance of the alignment based on a calculated correlation between a convexity measurement of the cleaning tool and a position of the support element intended for a height or a roughness modification. According to some embodiments, the processor may further select the predetermined location based on the calculated correlation and may further control the alignment operation to rotate the support structure about a horizontal axis.

[0012] According to some embodiments, the cleaning tool may be made of quartz (Si02), and the quartz may be coated with any one of Chromium Nitride (CrN), Chromium Oxide (CrOx), or Tantalum Boride.

[0013] According to some embodiments a method is discloses for modifying substrate support elements of a substrate holder, the method being performed by one or more processors and includes aligning a predetermined region of interest of a substrate holder with a predetermined location of a cleaning tool, the substrate holder having a plurality of support elements protruding from a first side of the substrate holder, and the cleaning tool having a spherical main body, manipulating a movement of a support structure such that the alignment produces a contact between the predetermined region of interest and the predetermined location, the support structure holding the substrate holder in a transverse manner from a second side of the substrate holder, and initiating a cleaning operation of the predetermined region of interest.

[0014] According to some embodiments, a lithographic apparatus may be disclosed including a material removing device for modifying substrate support elements of a substrate holder. According to some embodiments, the device includes a substrate holder having a plurality of support elements protruding from a first side of the substrate holder. The device may also include a support structure configured to hold the substrate holder in a transverse manner from a second side of the substrate holder, and a cleaning tool having a spherical main body. The device may also include a processor that aligns a predetermined region of interest of the substrate holder with a predetermined location of the cleaning tool, manipulates movement of the support structure such that the alignment produces a contact between the predetermined region of interest and the predetermined location, and initiates a cleaning operation of the predetermined region of interest.

[0015] Further features and advantages of the disclosure, as well as the structure and operation of various embodiments of the disclosure, are described in detail below with reference to the accompanying drawings. It is noted that the disclosure is not limited to the specific embodiments described herein. Such embodiments are presented herein for illustrative purposes only. Additional embodiments will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying schematic drawings, in which:

[0017] Figure 1 depicts a lithographic apparatus;

[0018] Figures 2A-2C depict schematic drawings of a tool system according to some embodiments;

[0019] Figures 3A-3C depict an alignment operation, according to some embodiments;

[0020] Figures 4A and 4B depict a cross-section of the tool of figures 2A-2C being used to modify a substrate holder;

[0021] Figures 5 A and 5B illustrate a cleaning operation, according to some embodiments; and

[0022] Figure 6 illustrates a cleaning method, according to some embodiments

[0023] The drawings provide an indication of certain features included in some embodiments of the disclosure. However, the drawings are not to scale. Examples of the size and range of sizes of certain features are described in the description below.

DETAILED DESCRIPTION

[0024] In order to avoid overlay errors during projection of a patterned beam of radiation on a substrate, it is desirable that the substrate top surface be flat. Unevenness of the supporting surfaces of the substrate support can lead to an uneven top surface of the substrate. Therefore, it is desirable to avoid unevenness in the substrate support.

[0025] Unevenness of the supporting surfaces can be caused by dissimilarity between the heights of material that makes up the support elements themselves. This is typically the case when a new substrate holder has been manufactured. Wear and contamination can also lead to unevenness. In a known embodiment, a substrate support contains a substrate table WT (otherwise referred to as a chuck) on which the substrate holder with the support elements is supported. In an alternative embodiment the substrate table WT and substrate holder can be integrated in a single unit. Unevenness can 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. Therefore these elements are carefully made level. Nevertheless it has been found that unevenness can also result when the substrate table WT and the substrate holder (and any other elements) are assembled or installed. Similar problems can be encountered with support tables or holders for other articles that have to be supported in a well-defined plane across the beam path, such as reflective patterning devices or transmission patterning devices.

[0026] US 2005/0061995 Al, the content of which is herein incorporated by reference in its entirety, provides a lithographic projection apparatus including a detector to detect height deviations of the support elements that affect a surface flatness of the article, a height adjustment device arranged to independently modify a height of the support element material of individual support elements when the support table is operable in the apparatus, and a controller (or a controlling processor) coupled between the detector and the height adjustment device and arranged to control the height adjustment device to adjust the height of the support elements corresponding to the detected height deviations of the support elements that affect the surface flatness of the article. It can be appreciated that the controller may be a central processing unit (CPU), a digital signal processor (DSP), or a device including circuitry that can perform processing. The controller may implement a combination of hardware, software, firmware, and computer readable code to be executed on the controller or on a readable medium. The controller and/or the computer readable medium can be distributed over a network coupled computer system so that the computer readable code is stored and executed in a distributed fashion.

[0027] An in situ height adjustment device can be used to alter the height of the material that at least the top of individual support elements are integrally made of, when the support table is at an operable position in the lithographic projection apparatus. By “operable,” it is meant that the support holder can be moved to a pattern projection position in the apparatus from the operable position without movements that are more disruptive to the support table assembly than during normal use. “Integrally made” refers to material that is used to manufacture the support holder or coatings or other material layers on the support elements, but not to accidental foreign material such as pollution. By adjusting the height of the support elements in the assembled support holder in the lithographic apparatus, at such an operable position, a reliable local and global height adjustment can be realized.

[0028] A detector can determine which of the support elements have a height deviation and a control unit controls the height adjustment device, for example, to remove a part of the material of selected support elements with excess height, but not from other support elements that do not have an excess height, or an excess height below a threshold. Such detector and height deviation adjustment tools are further described in Figure 1 herein.

[0029] Figure 1 schematically depicts a lithographic apparatus 100 according to one embodiment of the disclosure. The apparatus includes an illumination system (illuminator) IL configured to condition a radiation beam B (e.g. UV 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 positioning device 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 positioning device PW configured to accurately position the substrate in accordance with certain parameters. The substrate support can comprise a substrate table WT (otherwise referred to as a chuck) on which a substrate holder is supported. The substrate holder can be configured to support the substrate W. The apparatus further 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. including one or more dies) of the substrate W.

[0030] The illumination system can include various types of optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic or other types of optical components, or any combination thereof, to direct, shape, or control radiation.

[0031] 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 can use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterning device. The patterning device support can be a frame or a table, for example, which can be fixed or movable as required. The patterning device support can 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 can be considered synonymous with the more general term “patterning device”.

[0032] The term “patterning device” used herein can refer to any device that can be used to impart a radiation beam with a pattern in its cross-section so 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 can not exactly correspond to the desired pattern in the target portion of the substrate W, 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 a device being created in the target portion, such as an integrated circuit. [0033] The patterning device MA can be transmissive or reflective. Examples of patterning devices 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 a radiation beam that is reflected by the mirror matrix.

[0034] The term “projection system” used herein can be 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 can be considered as synonymous with the more general term “projection system”.

[0035] As here depicted, the apparatus is of a transmissive type (e.g. employing a transmissive mask). Alternatively, the apparatus can be of a reflective type (e.g. employing a programmable mirror array of a type as referred to above, or employing a reflective mask).

[0036] The lithographic apparatus can 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 can be used in parallel, or preparatory steps can be carried out on one or more tables or supports while one or more other tables or supports are being used for exposure. [0037] The lithographic apparatus can also be of a type wherein at least a portion of the substrate

W can 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. An immersion liquid can 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 a liquid is located between the projection system PS and the substrate W during exposure.

[0038] Referring to figure 1 , the illuminator IL receives a radiation beam B from a radiation source

SO. The source and the lithographic apparatus can 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 including, for example, suitable directing mirrors and/or a beam expander. In other cases the source can 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, can be referred to as a radiation system.

[0039] The illuminator IL can include an adjuster AD configured to adjust the angular intensity distribution of the radiation beam. Generally, at least the outer and/or inner radial extent (commonly referred to as s-outer and s-inner, respectively) of the intensity distribution in a pupil plane of the illuminator can be adjusted. In addition, the illuminator IL can include various other components, such as an integrator IN and a condenser CO. The illuminator can be used to condition the radiation beam, to have a desired uniformity and intensity distribution in its cross-section.

[0040] 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 is patterned by the patterning device. Having traversed 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 positioning device 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 positioning device 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 can 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 positioning device PM. Similarly, movement of the substrate table WT or “substrate support” can 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 can be connected to a short-stroke actuator only, or can be fixed. Patterning device (e.g. mask) MA and substrate W can be aligned using patterning device alignment marks Ml, M2 and substrate alignment marks PI, P2. Although the substrate alignment marks as illustrated occupy dedicated target portions, they can be located in spaces between target portions (these are known 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 can be located between the dies.

[0041] The depicted apparatus could be used in at least one of the following modes:

[0042] 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 at one time (i.e. a single static exposure). The substrate table WT or “substrate support” is then shifted in the X and/or 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.

[0043] 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” can 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.

[0044] 3. In another mode, the patterning device (e.g. mask table) MT or “mask support” is kept essentially stationary 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.

[0045] Combinations and/or variations on the above described modes of use or entirely different modes of use can also be employed.

[0046] As shown in figure 1 , the lithographic apparatus can include an in situ material removing device (MRD) configured to remove material from one or more support elements of the substrate holder of the lithographic apparatus. This MRD is configured to remove material from one or more support elements of the substrate holder in order to obtain a more even support for a substrate W supported on the substrate holder. The MRD can be located at a substantially stationary location and includes a material removal tool MRT, which is to be brought into contact with the one or more support elements to remove material of the one or more support elements. According to some examples, the MRT can also be located at a substantially stationary location and the one or more support elements can be moved in a motion (e.g., circular motion or the like) with respect to the MRT so as to remove material from the one or more support elements. According to some examples, the MRT can be movable with respect to the support elements such that the MRT can be moved in a motion (e.g., circular motion or the like) with respect to the support elements. Aspects of the material removal operation according to the present disclosure are further described with respect to Figures 2-6 below. [0047] The lithographic apparatus can further include a detector HDD configured to detect height deviations of the support elements that affect a surface flatness of an substrate W supported on the substrate holder. The detector HDD can for instance be a level sensor configured to measure the upper surface of a substrate W supported on the substrate holder. Such a level sensor is for instance disclosed in U.S. Pat. No. 5,191,200, which is herein incorporated 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 substrate itself, and which are caused by the substrate support, i.e. the support elements. According to some embodiments, detector HDD may be a combination of one or more components, including, for example, a light detector and/or a reticle with alignment marks, a light source, and a WS TIS sensor(s).

[0048] The detector HDD can be connected to a controller MRC coupled between the detector

HDD and the MRD. The controller can be configured to control the MRD to adjust the height of the support elements corresponding to the detected height deviations of the protrusions 4 that affect the surface flatness of the substrate. The controller MRC can be a separate controller adapted to create a flat surface by removing material of the support elements of the substrate holder, or it can be integrated in a controller configured to perform multiple control tasks in the lithographic apparatus.

[0049] Further details on the general operation of the MRD is disclosed in US 2005/0061995 Al, which is herein incorporated by reference in its entirety.

[0050] According to some embodiments, the removal of material from one or more support elements can be carried out by a relative movement between the material removal tool MRT and the one or more support elements. This relative movement can be performed by translating the one or more support elements with respect to the material removal tool MRT and/or translating the material removal tool MRT with respect to the one or more support elements. The material removal tool MRT can be rotated to enhance the removal of material of the support elements. According to some examples, as will be further described herein, the material removal tool MRT can be moved vertically and rotated about an axis in order to target a specific support element at a time.

[0051] Figures 2A-2C describe an MRT system 200 that can be used to modify the substrate holder to improve the flatness of the support elements (e.g., burls) of the substrate holder (e.g., clamp). MRT system 200 can correspond to the material removal tool MRT as described above. MRT system 200 can otherwise be referred to as a height adjustment tool. MRT system 200 can include components that can be manufactured to different shapes in order best suited to reach each support element individually. According to one embodiment, MRT system 200 can include a cleaning tool manufactured to have a spherical surface. As will be further described herein, the spherical surface of the cleaning tool enables the system to make contact with one support element of the substrate holder at a time. This enables more specific targeting and customized cleaning operations. [0052] According to one embodiment, there is provided MRT system 200 including a tool for modifying a substrate holder. The tool can be used, more specifically, for modifying substrate support elements of a substrate holder. The support elements can otherwise be referred to as burls. An example of MRT system 200 is shown in figures 2A-2C. As illustrated in Figures 2A-2C, MRT system 200 can include a substrate holder 204 having support elements 206. Substrate holder 204 can be secured by and have its movement controlled by support element 202. While the embodiment described in Figures 2A-2C illustrate support element 202 supporting substrate holder 204, it can be appreciated that support element 202 can be configured to support different components within MRT system 200. In one such embodiment, support element 202 can be configured to support cleaning tool 208. This can be in a situation where relative movement between cleaning tool and substrate holder is driven by movement of the tool instead of movement of the substrate holder (illustrated in Figures 2A-2C).

[0053] Support element 202 can control the movement of substrate holder 204 in an X-axis direction (lateral movement), Y-axis (longitudinal movement), and Z-axis (rotation about the axis). In this manner, support element 202 can move substrate holder 204 into a position where a surface of cleaning tool 208 aligns with a specific support element 206 in preparation for a cleaning operation. This can include movement, tilt, and lowering operations as will be further discussed herein.

[0054] According to some embodiments, Figures 2B and 2C show the surface of cleaning tool 208 contacting the substrate holder 204 at different support element locations (different burls). The surface of cleaning tool 208 shown in Figures 2A-2C can be a convex surface, where the substrate holder can be lowered (as shown in Figure 2B) and/or rotated at different angles (as shown in Figure 2C) in order to make contact with certain points of the convex surface of tool 1 as will be further described herein.

[0055] Figures 2A-2C illustrate an example of a substrate holder 204 having support elements 206 wherein cleaning tool 208 can be used for modifying the support elements 206 of the substrate holder 204. In other words, cleaning tool 208 1 can be used to remove material from the support elements 206. This can alter the overall height of at least one support element 206a and/or alter the roughness of at least one support element 206a. Support elements 206 can have support surfaces. The support surfaces can be used to contact an underside of a substrate W. Ideally, the support surfaces provide a flat plane on which the substrate W can be supported as described above. This enables the substrate W to be relatively flat when being irradiated, to reduce errors.

[0056] As described herein cleaning tool 208 can be part of a MRD and/or material removing tool

MRT. Cleaning tool 208 can be secured by base 210 where cleaning tool 208 can be removable for servicing/cleaning and can be placed in a fitted position within base 210.

[0057] Substrate holder 204 can be part of a substrate support configured to support a substrate W during projection of an image on the substrate W. The substrate holder 204 can be provided on a substrate table WT. The substrate holder 204 can for instance be held on the substrate table WT using a vacuum system (not shown). Similarly, during cleaning operations, substrate holder 204 can be held on support element 202 using a vacuum system (not shown).

[0058] The configuration of the multiple support elements 206 is designed to obtain an improved support for a substrate W supported thereon. Part of the substrate holder 204 is shown in cross-section in Figures 2A-2C, whereby some support elements 206 lie in the plane of the cross section and some support elements 206 lie behind this plane.

[0059] As described, the substrate holder 204 may not provide a flat supporting surface for the substrate W for a number of reasons. The substrate holder 204 can degrade over time as the support elements 206 are worn down due to interaction with various substrates. Wear of the support elements 206 leads to variation in the height of the support elements across the substrate holder 204.

[0060] Friction between the substrate W and the substrate holder 204 contributes to shape of the substrate W when positioned on the substrate holder 204. This friction changes over time due to contamination and smoothing of the support elements 206 due to wear. This can lead to variation in the roughness and height of the support elements 206 over the lifetime of the substrate holder 204. Current correction methods (Alignment, APC, Baseliner) can not always limit the impact on overlay error that can result in a reduced yield of patterned substrates. The friction can change as the support elements 208 are worn down, which can increase the contact area between the substrate W and the substrate holder 204. [0061] According to some embodiments, a larger contact area generates more van der Waals forces that causes “sticking” of the substrate W on the substrate holder 204. Providing a lower degree of roughness on the support surfaces of the support elements 206 can reduce the overall contact area and help reduce or avoid such sticking.

[0062] Generally, the support surfaces of support elements 206 that are used to contact the underside of the substrate W have a desired level of roughness. If the roughness of the support surfaces are too low then this leads to the substrate holder having increased friction, which can lead to sticking and overlay errors. Therefore, it is beneficial to reduce the friction by increasing the roughness of the support surface of the support elements. Thus, it is desirable to maintain the roughness at a desired level.

[0063] The roughness of the support surfaces is generally in the nm scale. In other words, the support surfaces of the support elements 208 generally have structures that are of the order of a few or tens of nanometers. For example, a substrate table WT can have contact roughness of at least 12 nm. Atomic force microscopy (AFM) can be used to characterize the contact roughness.

[0064] Additionally or alternatively, a white light interferometer can be used to measure roughness. White light measurements can roughly match atomic force microscopy (AFM) measurements. If the contact roughness is below approximately 12 nm, van der Waals bonding can generally increase contact pressure and effectively increase friction.

[0065] According to some embodiments, the substrate W, when positioned on the substrate holder

204, will rest on top of the peak structures of each of the support surfaces of the support elements 208. While not shown, it is understood that in these scenarios, substrate holder 204 can be positioned where support elements 206 are upwards facing to receive and support the substrate W. Thus, the flatness of the overall substrate holder 204 can be improved by reducing the peaks of roughness on support surfaces, which can have peaks higher than other support surfaces.

[0066] The roughness of the support surfaces can be determined by looking at contact pads to see where the contact pad contacts the support element. The amount of surface area of the contact pad that contacts the support surface for one support element (e.g., 206a) can indicate the roughness of that support element 206.

[0067] According to some embodiments, substrate holder 204 is modified to remove material using cleaning tool 208. This could otherwise be referred to as polishing. The material and roughness of cleaning tool 208 can be chosen (or formed) so that the resulting roughness and sticking of the substrate W on the substrate holder 204 are kept at a desired level. The cleaning tool 208 can be used regularly, perhaps daily, which can reduce or avoid system drift. Ideally, the roughness of the cleaning tool 208 will enable flatness, a desired roughness of the support surfaces and improved van der Waals forces.

[0068] According to some embodiments, cleaning tool 208 can be in contact with the support elements 206 and can have its relative position moved with respect to support elements 206. According to some embodiments illustrated herein, the relative movement can be generated by manipulating the positioning of substrate holder 204 relative to cleaning tool 208, as illustrated, for example, in Figures 2A- 2C. It can be appreciated that depending on the lithographic apparatus setup, some configurations can rely on relative movement being generated by manipulating the position of cleaning tool 208 relative to substrate holder 204 instead. According to one embodiment, cleaning tool 208 can be used to scratch the support surfaces of support elements 206 to alter the roughness of the support surfaces, which affects the friction between the support surfaces and the substrate W. Additionally or alternatively, cleaning tool 208 can be used to wear down at least one of the support surfaces in order to flatten the overall support plane provided by the support surfaces. Cleaning tool 208 can be used to make the substrate table WT more flat whilst also achieving a desired level of roughness. It can be beneficial to use cleaning tool 208 in a manner, which improves flatness without affecting the roughness (which can be at a preferred level). Alternatively, it can be beneficial to use tool 208 in a manner, which improves roughness without affecting the flatness (which can be at a preferred level). Modifying the support surfaces can generally refer to altering the flatness and/or roughness of the support surfaces. [0069] Multiple tools can be used. For example, a first tool can be used to generally improve the flatness of the substrate holder 204, without affecting the roughness too much, and a second tool can be used to generate the preferred roughness, without affecting the overall flatness too much (or vice versa). For example, the first tool and the second tool can have different configurations (i.e. protrusions arranged in different formations), which are more suited to affecting the flatness and/or roughness of the substrate table WT.

[0070] The design of cleaning tool 208 can alter how cleaning tool 208 affects the roughness and the flatness of the substrate holder 204 (e.g., table WT). Thus, for example, the composition and convexity of cleaning tool 208 can alter the effect the tool has on the cleaning operation. The desired radius of the convex surface of the cleaning tool is dependent on the flatness of the substrate holder, the distance between support elements 206, the desired contact area between the convex surface and the support elements, and the angular movement range of the support 202. Increasing the radius (i.e., decreasing the curvature) of the surface will result in a larger contact area.

[0071] According to some embodiments, cleaning tool 208 can have a uniform outer surface.

Alternatively, cleaning tool 208 can have different patches with different levels of roughness about its surface to generate different impact results when in contact with substrate holder 204. For example, some patches may have high degree of roughness on the cleaning tool with high special frequency (e.g., on the order of several grooves per support element). This provides an ability to collect debris that is generated from a resurfacing operation.

[0072] During wear and modification of the substrate support elements 206, debris can be generated. Debris generally refers to any contaminating material, but particularly, any material removed from the substrate support elements 206 and also from cleaning tool 208 itself. The debris can affect the roughness and overall flatness of the substrate holder 204.

[0073] According to some embodiments, contact between different locations within cleaning tool

208 and support elements 206 can help reduce the accumulation of debris in one specified location that can degrade the performance of cleaning tool 208. Additionally, cleaning tool 208 can have protrusions at predetermined locations creating a storage room for debris inside cleaning tool 208 (e.g., allowing debris to accumulate in the gaps between the multiple protrusions). Accordingly, debris is less likely to remain on the top of the support surfaces of the substrate support elements 206. This reduces or prevents contamination on the support surfaces.

[0074] The convexity of cleaning tool 208 can provide several benefits. For example, the surface area of cleaning tool 208 in contact with the substrate holder 204 can be controlled to average out smaller spatial frequencies in the overall flatness of the substrate holder 204. [0075] Additionally, the convexity means that smaller areas of cleaning tool 208 are in contact with the substrate holder 204 when in use. This allows for scratching to occur to provide a desired level of roughness to the support surfaces, which improves “sticking” issues. The smaller contact areas also provide the ability to perform cleaning operations targeting one support element at a time. This can provide a more targeted cleaning operation, thereby expediting the cleaning process. The targeted cleaning operations will be further discussed with reference to Figures 3-6 below.

[0076] Cleaning tool 208 can be made of various materials. According to some embodiments, the hardness of cleaning tool 208 has a hardness, which is the same or higher than the hardness of the support surfaces of support elements 206. Advantageously, if the hardness of cleaning tool 208 is harder than support elements 206, then interaction between cleaning tool 208 and the support surfaces of support elements 206 will wear down substrate holder 204 rather than cleaning tool 208. Advantageously, if the hardness of cleaning tool 208 is similar to the hardness of the support surfaces, then this can lead to high roughness of the support surfaces due to interaction between cleaning tool 208 and the support surface. [0077] Preferably, cleaning tool 208 is made of a relatively hard and tough material. Cleaning tool

208 can comprise quartz (Si02) and can further be coated with any one of Chromium Nitride (CrN), Chromium Oxide (CrOx), or Tantalum Boride. Cleaning tool 208 can be formed from a single piece of material. Thus, cleaning tool 208 can be formed of one of these materials. Alternatively, cleaning tool 208 can be formed of a combination of materials including at least one of these materials. In particular, the material chosen can be at least one of carbon reinforced silicon carbide, silicone carbide, aluminum oxide and/or diamond like carbon. Additionally or alternatively, cleaning tool 208 can have a layer or coating formed of at least one of these materials.

[0078] The back surface 8 of cleaning tool 208 can be provided in various shapes such that cleaning tool 208 is more easily and/or securely kept in place within base 210. Cleaning tool 208 can be connected or connectable to a tool support within base 210 (not shown) or can be connectable to support element 202 depending on the configuration. As noted previously, the relative movement driven by support element 202 can be provided by manipulating movement of substrate holder 204, as is shown in Figures 2A-2C, or alternatively, can be provided by manipulating movement of cleaning tool 208. The back surface 8 of cleaning tool 208 can comprise at least one indent to fit with support 210.

[0079] During use, it can be preferable for cleaning tool 208 to be kept substantially flat with respect to the substrate holder 204. In other words, it can be preferable to keep the main body/base of cleaning tool 208 substantially parallel to the surface of the substrate holder 204. However, variation in the orientation of cleaning tool 208 can allow for uneven support surfaces to be more efficiently worn down or flattened. Moreover, cleaning tool support 202 can be connected in a manner than allows variation of the orientation. [0080] Cleaning tool 208 can be part of a larger system comprising multiple tools. The multiple tools can have the same or different convexities based on surface areas and other parameters that are to be cleaned. Cleaning tool 208 can be used to clean over a whole substrate holder 204. In other words, cleaning tool 208 can be used to contact each support element 206 at least once.

[0081] A method can be provided using cleaning tool 208 described above. More specifically, the method can be for modifying substrate support elements 206 of a substrate holder 204. The substrate support elements 206 can include support surfaces for supporting a substrate W. The method can comprise providing a cleaning tool 208 as described above. The method can further comprise contacting at least some of the support surfaces of the substrate holder 204 with the distal convex portion of cleaning tool 208 and using cleaning tool 208 to modify the support surfaces.

[0082] Substrate holder 204 can be moved along cleaning tool 208 in order to remove material from the tops of the substrate support elements 206, which cleaning tool 208 contacts. Alternatively, cleaning tool 208 can be moved relative to the substrate holder 204, e.g. whilst the substrate holder 204 is kept stationary. For example, an MRD can be configured to move cleaning tool 208 over the substrate support elements 22, while the substrate holder 204 is not moved, or vice versa. Alternatively, the substrate holder 204 and cleaning tool 208 can be simultaneously moved. According to some embodiments, a degree of relative motion is desired to achieve the desired cleaning results, independent of whether cleaning tool 208 or substrate holder 204 is moved.

[0083] The pressure in the z-direction between cleaning tool 208 and the substrate support elements 206, used to obtain an abrasive effect, can be exerted by the substrate holder 204 or cleaning tool 208 (or more specifically the MRD) or by both. Preferably, the use support 202 (supporting either cleaning tool 208 or substrate holder 204 in the alternative) can be accurately controlled because if the force imparted by cleaning tool 208 is too large, then this can have a negative impact on flatness of the substrate holder 204.

[0084] Cleaning tool 208 be used in a variety of ways. For example, cleaning tool 208 can be used to modify the whole substrate holder 204, i.e. to process the whole substrate holder 204 in one sitting. Alternatively, cleaning tool 208 can be used to modify a localized area, i.e. a portion of the whole substrate holder 204. The convex shape properties of cleaning tool 208 enable strategic cleaning of localized areas. In some examples, the localized areas by include one or more support elements 206. In some examples, the localized area can include one support element 206. The frequency of using cleaning tool 208 can vary. For example, local cleaning of a specific portion of the substrate holder 208 can be carried out several times a day, e.g. 4-5 times daily. Larger cleaning of the whole of the substrate holder 204 can be carried out less frequently, e.g. daily or weekly. The frequency and type of modification can be determined based on, for example, measurements taken indicating the flatness of the substrate W and/or the substrate holder 204. The flatness of the substrate holder 204 is considered to be the flatness of the support elements 206 (and their respective support surfaces) on which the substrate W is positioned.

[0085] A lithographic apparatus can be provided comprising cleaning tool 208 as described above.

A lithographic apparatus, incorporating cleaning system 200, can be configured to modify substrate support elements 206 of a substrate holder 202 using cleaning tool 208. The lithographic apparatus can comprise a substrate holder 204 having a plurality of support elements 206 that are configured to support a substrate. [0086] The lithographic apparatus comprising cleaning tool 208 can be all or part of the lithographic apparatus described above in relation to Figure 1. The lithographic apparatus comprising cleaning tool 208 can be at least part of a metrology device and/or an inspection device (e-beam). The lithographic apparatus comprising cleaning tool 208 can be used in conjunction with the lithographic apparatus described in Figure 1. The lithographic apparatus comprising cleaning tool 208 can more generally be referred to as an apparatus configured to modify substrate support elements 206 of a substrate holder.

[0087] The lithographic apparatus comprising cleaning tool 208 can further comprise a detector configured to detect a height deviation of one or more of the support elements that affect a surface flatness of the substrate supported on the substrate holder. The detector can correspond to the detector FIDD described earlier. Cleaning tool 208 can be configured to modify a height of the one or more support elements corresponding to the detected height deviation of the support elements.

[0088] Figures 2B and 2C illustrate a lowering operation and a rotating operation respectively, according to some embodiments. These operations are further described herein after with regard to the remaining figures.

[0089] Figures 3A-3C illustrate lowering and rotating operations 300 according to some embodiments. Figure 3A, for example, depicts a lowered portion of cleaning system 200. Specifically, the lowered portion can include support structure 302, substrate holder 304, and substrate support elements 306. It can be appreciated that elements 302, 304, 306 and 308 are described in greater detail with respect to Figures 2A-2C, and the depiction of Figures 3 A-3C illustrate movement and alignment between cleaning tool 308 and the combination of elements 302, 304, and 306 (specifically, substrate holder 304).

[0090] According to some embodiments, Figure 3A illustrates an operation that aligns a predetermined region of interest (e.g., region 314) of substrate holder 304 with a predetermined location (e.g., location 312) of cleaning tool 308. Such alignment can be performed based on one or more measurements performed by a detector that can be configured to detect height deviation of support elements as further described herein below. Upon a detection reading, the detector can be configured to transmit a reading signal to the controller providing measured parameters of the support elements. In one example, the measured parameters can include a height deviation of the support elements. Height deviation can be understood as a deviation from an average height of all the support elements of the substrate holder 304 that would be considered as creating a flat surface for substrate holder 304 to receive a substrate. In other words, the deviation can be understood as a length of a support element that is beyond this average, which causes the substrate holder to be unable to provide a flat surface. The detector can also detect roughness levels of the support surfaces of support elements 306. This enables the controller to determine if additional cleaning can be desired/required and/or debris removal.

[0091] Figures 3B and 3C illustrate relative movement between cleaning tool 308 and the combination of support element 302, substrate holder 304 and support elements 306. According to some embodiments, upon detection of a second support element from amongst support elements 306, the controller can align a new region of interest 314 with a new location 316. It can be appreciated that the region of interest 314 can correspond to one or more support elements. For example, how cleaning tool 308 aligns with the combination of elements 302, 304, and 306 can depend on the convexity of cleaning tool 308 and the size of the region of interest 314. According to some examples, the convexity of cleaning tool 308 can be uniform throughout cleaning tool 308. According to yet another embodiment, upon detection of yet another support element that can be a candidate for a removal operation, the controller can align new region of interest 314 (corresponding to one or more support elements) with a predetermined location 318. It can be understood that the alignment operation can include a series of movements along the X, Y, and Z direction including lateral movements, longitudinal movements, tilt movements and rotation movements of support element 302.

[0092] Figure 4 represents section views of an exemplary cleaning operation. For example, according to some embodiments, a cleaning operation relying on an initial alignment between support element 404 and cleaning tool 408 can begin by tilting the support element 404 in a direction that brings one or more support elements 406 into closer proximity with cleaning tool. In a second step, support element 402 can be lowered by a distance sufficient to establish a level of contact between one or more support elements. According to some embodiments, the level of contact and pressure of contact can be determined by the controller based on the type of cleaning that is to be performed. For example, resurfacing operations can require a higher level of pressure applied by support element 402 onto cleaning tool 408.

[0093] Figures 5A and 5B illustrate a cleaning operation according to exemplary embodiments.

Figure 5A illustrates a planar view of a substrate holder having a plurality of support elements 506 within dimensions 520 and 530. Figure 5B illustrates an enlarged view of the substrate holder. Figure 5B illustrates an exemplary targeted cleaning operation according to some embodiments. In one example, targeted cleaning can be a cleaning operation of a few targeted support elements 506 determined to have undesirable physical parameters (e.g., height deviation measurement, etc.). In yet another example, the cleaning operation can be carried out for the entire substrate holder in a series of raster scan motions that perform a targeted cleaning operation on an individual support element basis. According to some embodiments, the cleaning operation may comprise a circular motion performed by MRT system 200 for a predetermined duration and within a predetermined radius. For example, the predetermined duration can depend on factors such as the roughness of a support surface and/or a measured height deviation. In other words, the predetermined duration may depend on time required to resurface/clean the support element (e.g., support element 206a) to a desired height, flatness, and/or level of roughness.

[0094] According to some embodiments, each targeted cleaning operation of a support element

506 can include an operation where a support element is tilted, moved and aligned in a manner targeting a predetermined support element 506. Next, upon contact between the support element and a surface of the cleaning tool, the support element can be moved in a small diameter circle to perform a cleaning operation of the predetermined support element. According to some embodiments, the cleaning operation can include a scrubbing operation. According to some embodiments, the small diameter can be 1mm diameter. According to some embodiments, the support element can be moved across the cleaning tool in order to make contact with a next desired support element. Such movement can be movement to the right, to the left, up, or down, based on the location of the support element and the type of scan being performed (e.g., a raster scan pattern) as illustrated in Figure 5B. According to some embodiments, for a more expedient cleaning operation, the movement between support elements (e.g., the transition to cleaning one support element to the next) may be achieved by a tilt operation of substrate holder 202.

[0095] Figure 6 illustrates an exemplary method 600 for modifying substrate support elements 206 of a substrate holder 204 according to some embodiments. Method 600 can include aligning a predetermined region of interest of a substrate holder (e.g., region 314) with a predetermined location of a cleaning tool (e.g., location 312), as illustrated in step 602. Moreover, method 600 can also include manipulating a movement of a support structure (e.g., 302) such that the alignment produces a contact between the predetermined region of interest and the predetermined location, as illustrated in step 604. Additionally, method 600 can further include initiating a cleaning operation of the predetermined region of interest, as illustrated in step 606.

[0096] It can be appreciated that method 600 can include additional modifying steps based on the measurements and the structural components involved. For example, according to some embodiments, the predetermined region of interest can include one or more support elements. According to some embodiments, the predetermined region of interest comprises one support element having a support surface. In one example, the produced contact between the predetermined region of interest and the predetermined location comprises a contact between the support surface and the predetermined location of the cleaning tool. [0097] According to some embodiments, method 600 can further include measuring, with a detector, physical parameters associated with the support surface. In one example, the physical parameters include a degree of roughness of the support surface. Moreover, the physical parameters can include a height deviation measurement of one or more support elements of the substrate holder, the height deviation measurement being a detected height deviation from a predetermined degree of surface flatness of the substrate holder. The cleaning operation of method 600 can also include modifying a height of the support element corresponding to the detected height deviation of the support element.

[0098] According to some embodiments, the aligning operation of method 600 can further include a lowering operation and a tilting operation of the support structure to align the predetermined region of interest with the predetermined location. Method 600 can also include calculating a correlation between a convexity measurement of the cleaning tool and a position of the support element intended for a height or a roughness modification, and aligning the predetermined region of interest with the predetermined location based on the calculated correlation. According to some embodiments, such correlation measurement can enable the controller to determine which portion of the cleaning tool is best suited to be in contact with a support element intended for a modification in view of the location of the intended support element.

[0099] According to some embodiments, method 600 can further include selecting the predetermined location based on the calculated correlation wherein the aligning includes a rotation operation of the support structure about a vertical axis (e.g., Y axis). Within method 600, the cleaning tool used can be composed of material comprising silicon-infiltrated silicon carbide, silicon carbide, aluminum oxide, or diamond like carbon.

[0100] Hereinabove the use of cleaning system is described for the removal of material of one or more substrate support elements 206 of a support holder 204 to provide a more even support for a substrate support thereon. A similar cleaning system also be used for other article support systems, such as a patterning device support. Thus, cleaning tool 208 can be used more generally to contact support surfaces. For example, a lithographic apparatus is provided in an embodiment. In this embodiment, the lithographic apparatus is configured to modify support elements of an article holder.

[0101] The lithographic apparatus comprising cleaning tool 208 can be ah or part of the lithographic apparatus described above in relation to Figure 1. The lithographic apparatus comprising cleaning tool 208 can be at least part of a metrology device and/or an inspection device (e-beam). The lithographic apparatus comprising cleaning tool 208 can be used in conjunction with the lithographic apparatus described in Figure 1. The lithographic apparatus comprising cleaning tool 208 can more generally be referred to as an apparatus configured to modify support elements of an article holder.

[0102] According to some embodiments, the lithographic apparatus comprising cleaning tool 208 can further comprising a detector that detects a height deviation of one or more of the support elements that affect a surface flatness of the article supported on the article holder. The detector can correspond to the detector HDD described earlier. The detector can be similar to the detector HDD but can be used to detect a surface flatness of an article, rather than a substrate. Cleaning tool 208 can be configured to modify a height of the one or more support elements corresponding to the detected height deviation of the support elements.

[0103] The tool used in this embodiment for modifying an article can have any or all of the variations described above for cleaning tool 208 used specifically to modify the substrate holder 204. [0104] The provision of cleaning tool 208 according to an embodiment of the disclosure in a lithographic apparatus offers a number of benefits over existing systems. A first benefit is that the substrate table/holder (or other support surfaces) can be installed in a lithographic apparatus with a smaller flatness and thus at a lower cost, as the substrate holder can be flattened in the lithographic apparatus by using cleaning tool 208. Further, wear of the substrate holder is no longer of great importance as the non-flatness due to wear can be corrected. As a result, less stringent restrictions on the wafer table/ substrate holder 204 material can be used. Moreover, by using cleaning tool 208, the flatness of the support surfaces can be improved in the course of time therewith improving the overlay performance of the lithographic apparatus. [0105] The embodiments may further be described using the following clauses:

1. A device for modifying substrate support elements of a substrate holder, the device comprising: a substrate holder having a plurality of support elements protruding from a first side of the substrate holder; a support structure configured to hold the substrate holder in a transverse manner from a second side of the substrate holder; a cleaning tool having a spherical main body; and a processor configured to align a predetermined region of interest of the substrate holder with a predetermined location of the cleaning tool, manipulate movement of the support structure such that the alignment produces a contact between the predetermined region of interest and the predetermined location, and initiate a cleaning operation of the predetermined region of interest.

2. The device of clause 1 , wherein the predetermined region of interest comprises one or more support elements.

3. The device of clause 1 , wherein the predetermined region of interest comprises one support element having a support surface. 4. The device of clause 3, wherein the contact produced between the predetermined region of interest and the predetermined location comprises a contact between the support surface and the predetermined location of the cleaning tool.

5. The device of clause 4, further comprising a detector, the detector being configured to measure physical parameters of the support surface.

6. The device of clause 5, wherein the physical parameters comprise a degree of roughness of the support surface.

7. The device of clause 5, wherein the physical parameters comprise a height deviation measurement of one or more support elements of the substrate holder, the height deviation measurement being a detected height deviation from a predetermined degree of surface flatness of the substrate holder.

8. The device of clause 7, wherein the processor is further configured to control the cleaning operation to modify a height of the support element corresponding to the detected height deviation of the support element.

9. The device of clause 1, wherein the processor is further configured to control the alignment to lower and tilt the support structure to align the predetermined region of interest with the predetermined location.

10. The device of clause 9, wherein the processor is further configured to control the performance of the alignment based on a calculated correlation between a convexity measurement of the cleaning tool and a position of the support element intended for a height or a roughness modification.

11. The device of clause 10, wherein the processor is further configured to select the predetermined location based on the calculated correlation.

12. The device of clause 9, wherein the processor is further configured to control the alignment operation to rotate the support structure about a horizontal axis.

13. The device of clause 1, wherein the cleaning tool is comprised of quartz (Si02), and wherein the quartz is coated with any one of Chromium Nitride (CrN), Chromium Oxide (CrOx), or Tantalum Boride.

14. A method for modifying substrate support elements of a substrate holder, the method being performed by a processor comprising: aligning a predetermined region of interest of a substrate holder with a predetermined location of a cleaning tool, the substrate holder having a plurality of support elements protruding from a first side of the substrate holder, and the cleaning tool having a spherical main body; manipulating a movement of a support structure such that the alignment produces a contact between the predetermined region of interest and the predetermined location, the support structure holding the substrate holder in a transverse manner from a second side of the substrate holder; and initiating a cleaning operation of the predetermined region of interest. 15. The method of clause 14, wherein the predetermined region of interest comprises one or more support elements.

16. The method of clause 14, wherein the predetermined region of interest comprises one support element having a support surface.

17. The method of clause 16, wherein the contact produced between the predetermined region of interest and the predetermined location comprises a contact between the support surface and the predetermined location of the cleaning tool.

18. The method of clause 17, further comprising measuring, with a detector, physical parameters associated with the support surface.

19. The method of clause 18, wherein the physical parameters comprise a degree of roughness of the support surface.

20. The method of clause 18, wherein the physical parameters comprise a height deviation measurement of one or more support elements of the substrate holder, the height deviation measurement being a detected height deviation from a predetermined degree of surface flatness of the substrate holder.

21. The method of clause 20, wherein the cleaning operation further comprises modifying a height of the support element corresponding to the detected height deviation of the support element.

22. The method of clause 14, wherein the aligning further comprises a lowering operation and a tilting operation of the support structure to align the predetermined region of interest with the predetermined location.

23. The method of clause 22, further comprising: calculating a correlation between a convexity measurement of the cleaning tool and a position of the support element intended for a height or a roughness modification; and aligning the predetermined region of interest with the predetermined location based on the calculated correlation.

24. The method of clause 23, further comprising selecting the predetermined location based on the calculated correlation.

25. The method of clause 22, wherein the aligning further comprises a rotation operation of the support structure about a horizontal axis.

26. The method of clause 14, wherein the cleaning tool is comprised of quartz (Si02), and wherein the quartz is coated with any one of Chromium Nitride (CrN), Chromium Oxide (CrOx), or Tantalum Boride.

27. A lithographic apparatus comprising: a material removing device for modifying substrate support elements of a substrate holder, the device comprising: a substrate holder having a plurality of support elements protruding from a first side of the substrate holder; a support structure configured to hold the substrate holder in a transverse manner from a second side of the substrate holder; a cleaning tool having a spherical main body; and a processor configured to align a predetermined region of interest of the substrate holder with a predetermined location of the cleaning tool, manipulate movement of the support structure such that the alignment produces a contact between the predetermined region of interest and the predetermined location, and initiate a cleaning operation of the predetermined region of interest.

[0106] Although specific reference can 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 can 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. The skilled artisan will appreciate that, in the context of such alternative applications, any use of the terms “wafer” or “die” herein can be considered as synonymous with the more general terms “substrate” or “target portion”, respectively. The substrate referred to herein can 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 can be applied to such and other substrate processing tools. Further, the substrate can be processed more than once, for example in order to create a multi-layer IC, so that the term substrate used herein can also refer to a substrate that already contains multiple processed layers.

[0107] Although specific reference can have been made above to the use of embodiments of the disclosure in the context of optical lithography, it will be appreciated that the disclosure can 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 can be pressed into a layer of resist supplied to the substrate whereupon the resist is cured by applying electromagnetic radiation, heat, pressure or a combination thereof. The patterning device is moved out of the resist leaving a pattern in it after the resist is cured.

[0108] The terms “radiation” and “beam” used herein encompass ah 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.

[0109] The term “lens”, where the context allows, can refer to any one or combination of various types of optical components, including refractive, reflective, magnetic, electromagnetic and electrostatic optical components.

[0110] While specific embodiments of the disclosure have been described above, it will be appreciated that the disclosure can be practiced otherwise than as described. The descriptions above are intended to be illustrative, not limiting. Thus it will be apparent to one skilled in the art that modifications can be made to the disclosure as described without departing from the scope of the claims set out below. [0111] The descriptions above are intended to be illustrative, not limiting. Thus, it will be apparent to one skilled in the art that modifications can be made to the disclosure as described without departing from the scope of the claims set out below.

Claims

2. The device of claim 1, wherein the predetermined region of interest comprises one or more support elements.

3. The device of claim 1, wherein: the predetermined region of interest comprises one support element having a support surface; the contact produced between the predetermined region of interest and the predetermined location comprises a contact between the support surface and the predetermined location of the cleaning tool; the device further comprises a detector, the detector being configured to measure physical parameters of the support surface; the physical parameters comprise a degree of roughness of the support surface; and the physical parameters comprise a height deviation measurement of one or more support elements of the substrate holder, the height deviation measurement being a detected height deviation from a predetermined degree of surface flatness of the substrate holder.

4. The device of claim 3, wherein the processor is further configured to control the cleaning operation to modify a height of the support element corresponding to the detected height deviation of the support element.

5. The device of claim 1 , wherein the processor is further configured to control the alignment to lower and tilt the support structure to align the predetermined region of interest with the predetermined location.

6. The device of claim 5, wherein the processor is further configured to: control the performance of the alignment based on a calculated correlation between a convexity measurement of the cleaning tool and a position of the support element intended for a height or a roughness modification; and select the predetermined location based on the calculated correlation.

7. The device of claim 5, wherein the processor is further configured to control the alignment operation to rotate the support structure about a horizontal axis.

8. The device of claim 1, wherein the cleaning tool is comprised of quartz (Si02), and wherein the quartz is coated with any one of Chromium Nitride (CrN), Chromium Oxide (CrOx), or Tantalum Boride.

9. A method for modifying substrate support elements of a substrate holder, the method being performed by a processor comprising: aligning a predetermined region of interest of a substrate holder with a predetermined location of a cleaning tool, the substrate holder having a plurality of support elements protruding from a first side of the substrate holder, and the cleaning tool having a spherical main body; manipulating a movement of a support structure such that the alignment produces a contact between the predetermined region of interest and the predetermined location, the support structure holding the substrate holder in a transverse manner from a second side of the substrate holder; and initiating a cleaning operation of the predetermined region of interest.

10. The method of claim 9, wherein the predetermined region of interest comprises one or more support elements.

11. The method of claim 9, wherein: the predetermined region of interest comprises one support element having a support surface; the contact produced between the predetermined region of interest and the predetermined location comprises a contact between the support surface and the predetermined location of the cleaning tool; the method further comprising measuring, with a detector, physical parameters associated with the support surface; the physical parameters comprise a degree of roughness of the support surface; and the physical parameters comprise a height deviation measurement of one or more support elements of the substrate holder, the height deviation measurement being a detected height deviation from a predetermined degree of surface flatness of the substrate holder.

12. The method of claim 11, wherein the cleaning operation further comprises modifying a height of the support element corresponding to the detected height deviation of the support element.

13. The method of claim 9, wherein the aligning further comprises a lowering operation and a tilting operation of the support structure to align the predetermined region of interest with the predetermined location, and the method further comprises: calculating a correlation between a convexity measurement of the cleaning tool and a position of the support element intended for a height or a roughness modification; aligning the predetermined region of interest with the predetermined location based on the calculated correlation; and selecting the predetermined location based on the calculated correlation, wherein the aligning further comprises a rotation operation of the support structure about a horizontal axis.

14. The method of claim 9, wherein the cleaning tool is comprised of quartz (Si02), and wherein the quartz is coated with any one of Chromium Nitride (CrN), Chromium Oxide (CrOx), or Tantalum Boride.

15. A lithographic apparatus comprising: a material removing device for modifying substrate support elements of a substrate holder, the device comprising: a substrate holder having a plurality of support elements protruding from a first side of the substrate holder; a support structure configured to hold the substrate holder in a transverse manner from a second side of the substrate holder; a cleaning tool having a spherical main body; and a processor configured to align a predetermined region of interest of the substrate holder with a predetermined location of the cleaning tool, manipulate movement of the support structure such that the alignment produces a contact between the predetermined region of interest and the predetermined location, and initiate a cleaning operation of the predetermined region of interest.