CN115698864A

CN115698864A - Substrate holder for use in a lithographic apparatus and method of manufacturing a substrate holder

Info

Publication number: CN115698864A
Application number: CN202180041129.5A
Authority: CN
Inventors: A·F·J·德格鲁特; M·A·阿克巴斯; A·齐弗契桑迪奇; J·J·邓; M·涅可柳多娃; R·迈尔; S·古普塔; R·C·斯坦尼肯; J·M·W·范登温凯尔; C·M·奥利索维奇; M·佩里
Original assignee: ASML Holding NV
Current assignee: ASML Holding NV
Priority date: 2020-06-08
Filing date: 2021-05-25
Publication date: 2023-02-03
Also published as: JP7477652B2; JP2023529577A; KR20230007508A; TW202212984A; EP4162324A1; TWI824252B; WO2021249768A1

Abstract

Described herein is a method of producing a substrate holder for use in a lithographic apparatus, the substrate holder comprising a plurality of burls projecting from the substrate holder and each burl having a distal surface configured to engage with a substrate. The method includes applying a coating of an abrasion resistant material at a distal surface of one or more of the plurality of burls via plasma enhanced chemical vapor deposition. The applying of the coating comprises adjusting a Radio Frequency (RF) power of an RF electrode in a range of 100W to 1000W to generate a plasma; and exposing the one or more burls to a precursor gas at a gas flow rate of between 20sccm to 300sccm in the chamber, the precursor gas being hexane.

Description

Substrate holder for use in a lithographic apparatus and method of manufacturing a substrate holder

Cross Reference to Related Applications

This application claims priority from U.S. provisional patent application No. 62/036,028, filed on 8/6/2020, which is incorporated herein by reference in its entirety.

Technical Field

The present disclosure relates to a substrate holder for use in a lithographic apparatus and a method of manufacturing a substrate holder.

Background

A lithographic apparatus is a machine that is configured to apply a desired pattern onto a substrate. Lithographic apparatus can be used, for example, in the manufacture of Integrated Circuits (ICs). A lithographic apparatus may, for example, project a pattern (also commonly referred to as a "design layout" or "design") of a patterning device (e.g., a mask) onto a layer of radiation-sensitive material (resist) disposed on a substrate (e.g., a wafer).

As semiconductor manufacturing processes continue to advance, the size of circuit elements has continued to decrease over decades, while the amount of functional elements, such as transistors, per device has steadily increased, following a trend commonly referred to as "moore's law". To satisfy moore's law, the semiconductor industry is seeking technologies that can produce smaller and smaller features. To project a pattern onto a substrate, a lithographic apparatus may use electromagnetic radiation. The wavelength of this radiation determines the minimum size of features patterned on the substrate. Typical wavelengths currently used are 365nm (i-line), 248nm (KrF), 193nm (ArF) and 13.5nm (EUV).

In a lithographic apparatus, a substrate to be exposed (which may be referred to as a production substrate) is held on a substrate holder (sometimes referred to as a wafer stage). The substrate holder is movable relative to the projection system. The substrate holder typically comprises a solid body made of a rigid material and having similar dimensions in a plane as the production substrate to be supported. The surface of the solid body facing the substrate is provided with a plurality of protrusions (called burls). The distal surfaces of the burls conform to the flat plane and support the substrate. Burls provide several advantages: contaminant particles on the substrate holder or on the substrate are likely to fall between the burls and thus not cause deformation of the substrate; machining the burls to make their ends conformal to a plane easier than flattening the surface of the solid body; and the properties of the burls can be adjusted, for example, to control the clamping of the substrate.

However, the burls of the substrate holder wear during use, e.g. due to repeated loading and unloading of substrates. Uneven wear of the burls can result in unevenness of the substrate during exposure, which can lead to a reduction in the process window and, in extreme cases, imaging and or overlay errors. Due to the very precise manufacturing specifications, the substrate holder is expensive to manufacture, making it desirable to extend the working life of the substrate holder.

Disclosure of Invention

In an embodiment, a method of manufacturing a substrate holder for use in a lithographic apparatus is provided. The substrate holder includes a plurality of burls projecting from the substrate holder, and each burl has a distal surface configured to engage a substrate. The method includes applying a coating of an abrasion resistant material at a distal surface of one or more of the plurality of burls via plasma enhanced chemical vapor deposition. The applying of the coating comprises adjusting a Radio Frequency (RF) power of an RF electrode in a range of 100W to 1000W to generate a plasma; and exposing the one or more burls to a precursor gas at a gas flow rate between 20sccm to 300sccm in the chamber, the precursor gas being hexane.

Furthermore, in an embodiment, a method of manufacturing a substrate holder for use in a lithographic apparatus is provided. The substrate holder includes a plurality of burls projecting from the substrate holder, and each burl has a distal surface configured to engage a substrate. The method includes applying a coating of an abrasion resistant material at a distal surface of one or more of the plurality of burls via plasma enhanced chemical vapor deposition. The applying of the coating comprises adjusting a Radio Frequency (RF) power of an RF electrode in a range of 50W to 750W to generate a plasma; and exposing the one or more burls to a precursor gas at a gas flow rate of between 10 seem to 100 seem in the chamber, the precursor gas being acetylene.

Furthermore, in an embodiment, there is provided a substrate holder for use in a lithographic apparatus and configured to support a substrate. The substrate holder includes a body having a body surface and a plurality of burls projecting from the body surface. Each burl has a distal surface configured to engage with the substrate. The distal surface of the burls is substantially conformal with a support plane and is configured for supporting the substrate; and the distal surface of one or more of the plurality of burls is coated with a wear resistant material having a hardness in a range of 20GPa to 27GPa or 25GPa to 35GPa and a corrosion rate in a range of 0.1nm/hr to 2 nm/hr. The corrosion rate is measured by chronoamperometry (chronoamperometry) in dilute NaCl solution in a three-electrode electrochemical cell having a potential difference of about +2.5V between the working and counter electrodes and applied relative to a reference electrode.

Drawings

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

FIG. 1 is a block diagram of various subsystems of a lithography system, according to an embodiment.

FIG. 2A illustrates a substrate or wafer loaded onto a substrate holder (also referred to as a Wafer Table (WT)) via an electrostatic clamp (ESC) according to an embodiment, the substrate being supported on e-pins or lift pins in an unload position;

fig. 2B illustrates a substrate in a loading position on a substrate holder, in accordance with an embodiment;

2C-2F illustrate a sequence of loading a substrate onto a substrate holder, according to an embodiment;

FIG. 3A illustrates a substrate loaded on a substrate holder, the surface of the substrate holder including burls having a roughness on which the substrate rests, according to an embodiment;

fig. 3B is an example burl of the substrate holder of fig. 3A, according to an embodiment;

FIG. 4 is a flow diagram of a method for manufacturing a substrate holder according to an embodiment;

FIG. 5 illustrates an example plasma enhanced chemical vapor deposition arrangement, according to an embodiment;

embodiments will now be described in detail with reference to the accompanying drawings, which are provided as illustrative examples to enable those skilled in the art to practice the embodiments. It should be noted that the figures and examples below are not intended to limit the scope to a single embodiment, but rather other embodiments are possible by way of interchange of some or all of the described or illustrated elements. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. Where certain elements of the embodiments may be partially or fully implemented using known components, only those portions of such known components that are necessary for an understanding of the described embodiments will be described, and detailed descriptions of other portions of such known components will be omitted so as not to obscure the description of the embodiments. In this specification, embodiments showing a singular component should not be taken as limiting; rather, unless explicitly stated otherwise herein, the scope is intended to encompass other embodiments comprising a plurality of the same components, and vice versa. Moreover, applicants do not intend for any term in the specification or claims to be ascribed an uncommon or special meaning unless explicitly set forth as such. Further, the scope encompasses present and future known equivalents to the components referred to herein by way of illustration.

Detailed Description

Although the present disclosure describes features herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those skilled in the art with access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the invention would be of significant utility.

In the present disclosure, the term "mask" or "patterning device" as used herein may be broadly interpreted as referring to a generic patterning device that can be used to impart an incident beam with a patterned cross-section corresponding to a pattern to be created in a target portion of a substrate; the term "light valve" may also be used in this context. Examples of other such patterning devices besides classical masks (transmissive or reflective; binary, phase-shifting, hybrid, etc.) include:

a programmable mirror array. An example of such a device is a matrix-addressable surface having a viscoelastic control layer and a reflective surface. The underlying principles underlying such a device are (for example): addressed areas of the reflective surface reflect incident radiation as diffracted radiation, whereas unaddressed areas reflect incident radiation as undiffracted radiation. With the use of suitable filters, the non-diffracted radiation can be filtered out of the reflected beam, leaving only diffracted radiation; in this manner, the beam becomes patterned according to the addressing pattern of the matrix-addressable surface. The required matrix addressing can be performed using suitable electronic means. More information about such mirror arrays can be gleaned, for example, from U.S. Pat. nos. 5,296,891 and 5,523,193, which are incorporated herein by reference.

-a programmable LCD array. An example of such a configuration is given in U.S. Pat. No. 5,229,872, which is incorporated herein by reference.

By way of brief introduction, FIG. 1 illustrates an exemplary lithographic projection apparatus 10A. The main component is a radiation source 12A, which may be a deep ultraviolet excimer laser source or other type of source including an Extreme Ultraviolet (EUV) source (as discussed above, the lithographic projection apparatus need not have a radiation source itself); illumination optics that define partial coherence (expressed as standard deviation) and may include optics 14A, 16Aa, and 16Ab that shape radiation from source 12A; a patterning device 18A; and transmission optics 16Ac that project an image of the patterning device pattern onto the substrate plane 22A. A tunable filter or aperture 20A at the pupil plane of the projection optics may define a range of beam angles impinging on the substrate plane 22A, with the largest possible angle defining the numerical aperture NA = sin (Θ) of the projection optics _max )。

In a lithographic projection apparatus, a source provides illumination (i.e., light); the projection optics direct and shape the illumination via the patterning device and project the illumination onto the substrate. The term "projection optics" is broadly defined herein to include any optical component that can alter the wavefront of a radiation beam. For example, the projection optics may include at least some of the components 14A, 16Aa, 16Ab, and 16 Ac. The Aerial Image (AI) is the radiation intensity distribution at the substrate level. A resist layer on a substrate is exposed, and an aerial image is transferred to the resist layer as a latent "resist image" (RI) therein. A Resist Image (RI) can be defined as the spatial distribution of the solubility of the resist in the resist layer. A resist model may be used to compute a resist image from an aerial image, an example of which may be found in commonly assigned U.S. patent application No. 12/315,849, the disclosure of which is hereby incorporated by reference in its entirety. The resist model is only related to the properties of the resist layer (e.g., the effects of chemical processes that occur during exposure, PEB, and development). The optical properties of the lithographic projection apparatus (e.g., the properties of the source, patterning device and projection optics) dictate the aerial image. Since the patterning device used in a lithographic projection apparatus can be varied, it is desirable to separate the optical properties of the patterning device from the optical properties of the rest of the lithographic projection apparatus, including at least the source and the projection optics.

In this document, the terms "radiation" and "beam" are used to encompass all types of electromagnetic radiation, including ultraviolet radiation (e.g. having a wavelength of 365nm, 248nm, 193nm, 157nm or 126 nm) and EUV (extreme ultra-violet radiation, e.g. having a wavelength in the range of 5nm to 20 nm).

Furthermore, the lithographic projection apparatus may be of a type having one or more substrate holders, e.g., two substrate holders (and/or one or more patterning device tables, e.g., two patterning device tables). In such "multiple stage" machines the additional tables may be used in parallel, or preparatory steps may be carried out on one or more tables while one or more other tables are being used for exposure. A dual stage lithographic projection apparatus is described, for example, in US 5,969,441, which is incorporated herein by reference.

In a lithographic apparatus (e.g., fig. 1), a substrate to be exposed (which may be referred to as a production substrate) is held on a substrate holder (sometimes referred to as a wafer table or substrate holder). The substrate holder WT is designed to accurately position the substrate during exposure. The substrate table (e.g., WT in fig. 2A and 3A) may be movable relative to the projection apparatus. The substrate holder usually comprises a solid body made of a rigid material and having similar dimensions in the plane XY as the production substrate to be supported. The surface of the solid body facing the substrate is provided with a plurality of protrusions or protruding portions (called burls). The distal surface of the burls (see fig. 3B) conforms to the flat plane and supports the substrate. Burls provide several advantages: contaminant particles on the substrate holder or on the substrate are likely to fall between the burls and thus not cause deformation of the substrate; machining the burls to conform their ends to a plane is easier than flattening the surface of a solid body; and the properties of the burls can be adjusted, for example, to control the clamping of the substrate. In an embodiment, the burls reduce the contact area, thereby reducing friction and adhesion between the substrate holder WT and the substrate W.

However, the burls of the substrate holder wear during use, e.g., due to repeated loading and unloading of substrates. Uneven wear of the burls results in unevenness of the substrate during exposure (e.g., out-of-specification surface profile in the z-direction), which can lead to a reduction in process window and, in extreme cases, imaging and/or overlay errors. Due to the very precise manufacturing specifications, the substrate holder is expensive to manufacture and it is therefore desirable to increase the working life of the substrate holder.

Some substrate holders may be provided with a diamond-like carbon coating (DLC), typically SiC or SiSiC, on the body. However, wear, oxidation, and unstable friction of DLC-coated burls are considered to be important/significant problems causing deterioration of the substrate holder.

It is therefore desirable to coat the substrate holder, or at least the burls of the substrate holder, with a coating such as diamond or other superhard material. However, available manufacturing CVD techniques, such as for diamond growth, require higher deposition temperatures (400-1200 ℃), which can create higher thermal stresses and thus cause bending of the substrate holder. This in turn would require additional time consuming manufacturing steps to bring the substrate holder to the flatness specification.

Fig. 2A and 2B illustrate loading and unloading of a substrate W onto and from a substrate holder WT by means of a wafer handler WH. The substrate holder WT typically has a plurality of burls for supporting the substrate W. For example, more than 10,000 burls are provided on top of the substrate holder WT, which burls are in contact with the substrate W. When a substrate W is first loaded onto the substrate holder WT in preparation for exposure, the substrate W is supported by three or more ejector pins (e-pins, i.e., lift pins) (e.g., two pins are labeled PI1 and PI 2) that hold the substrate W. The wafer handler WH retraces when the substrate is positioned on the e-pin. To hold and support the substrate W on the substrate holder WT during stepping and scanning, the substrate W is clamped on burls (see, e.g., FIGS. 2A and 3A). The clamping mechanism may comprise, for example, a vacuum force in DUV, or an electrostatic force in EUV.

Although the substrate W is held by the e-pins, the substrate W will deform, e.g. become convex or concave, due to its own weight and the stress of the processed layer and the backside coating. To load the substrate W onto the substrate holder WT, the e-pins are retracted so that the substrate W is supported by the burls of the substrate holder WT. As the substrate W is lowered onto the burls of the substrate holder WT, the substrate W will contact at some locations (e.g., near the edges) before other locations (e.g., near the center). Any friction between the burls (see fig. 2C-2F) and the lower surface of the substrate W may prevent the substrate from relaxing completely to a flat, stress-free state. This may lead to focus and overlay errors during exposure of the substrate W.

Thicker and thicker layers on the wafer can result in bowed, i.e., bowed, wafers, e.g., wafers bowed to 400 μm. These deviations result in overlay defects on the wafer due to misalignment and distortion patterns. In-plane stress is introduced when the arcuate wafer is loaded and clamped on the substrate holder WT. Fig. 2C to 2F illustrate an example loading sequence of the substrate W, and the friction between the burls and the substrate W. Sequence of loading wafers from e-pins to the substrate holder WT or electrostatic clamp (ESC). For example, the wafer W on the E-pins travels down to the substrate table WT (see fig. 2C), the arcuate wafer W' contacts the substrate holder WT on the edge (see fig. 2D), the wafer W is clamped on the substrate holder WT (see fig. 2E) and the stress is locked into the wafer (fig. 2F). In such cases, the combination of wafer shape, coefficient of friction, and normal force cause WLG problems, such as positioning errors with respect to the reference grid.

The substrate holder WT is typically made of a ceramic material, such as silicon carbide (SiC) or SiSiC (a material having SiC particles in a silicon matrix). Such ceramic materials can be readily machined into desired shapes using conventional manufacturing methods. The ceramic material may wear out rapidly when the substrate is loaded and unloaded from the substrate holder WT. The relatively high coefficient of friction of the ceramic material may also prevent the substrate W from relaxing into a flat, stress-free state when loaded onto the substrate holder WT.

Referring to fig. 3A and 3B, in an embodiment, one or more burls 310 of the substrate holder WT comprise a burl body 312 coated with a coating 311 of a wear resistant material, e.g. diamond-like carbon (DLC). Such a coating 311 resists wear and reduces friction between the substrate holder and the substrate W. In an example, DLC can be deposited directly onto the burls of the substrate holder WT. In an example, the DLC can be deposited directly onto the entire substrate holder WT. Deposition of DLC is possible at temperatures below 300 ℃. Temperatures in excess of 300 ℃ may risk damage to the substrate holder.

In an embodiment, the coating 311 may include a first coating and a second coating of a wear resistant material (e.g., DLC). The first coating and the second coating may include features similar to those of coating 311. The first coating may be deposited directly onto the substrate holder such that the substrate holder will be coated by the first coating. A second coating may be deposited onto the first coating. The second coating may comprise a different composition and/or different properties than the first coating as described herein.

The inventors have recognized that the performance of such DLC-coated substrate holders, using existing coating techniques, does not meet substrate performance specifications (e.g., flatness, focus and overlay) (wear and corrosion of the substrate holder are fundamental to focus and overlay issues at the substrate). The DLC deposited on the substrate holder WT (those areas arranged to be in contact with the substrate) wears about 10 times faster than expected, i.e. about 10 times faster, thus requiring the substrate holder to be reground/refinished and reconditioned much earlier than the expected period of operation. In an embodiment, the substrate holder WT performance is measured using parameters such as Wafer Loading Grid (WLG) and flatness.

The deterioration of the substrate holder WT leads to a limited lifetime and therefore an earlier exchange of the substrate holder WT or repair of the surface may be required. The substrate holder may wear in terms of flatness and smoothness of the burl tops, e.g. a flower-like pattern. The origin of such degradation may be chemical wear, mechanical wear, or a combination thereof. Current substrate holder WT designs with DLC coatings show significant WLG drift and flatness degradation. For example, WLG drift rate is 20nm per 1 million substrate passes and flatness degradation is 10nm per 1 million substrate passes due to wear. In an embodiment, wear refers to a combination of all wear.

In an embodiment, the coating 311 is configured to improve substrate holder performance by reducing mechanical and chemical wear achieved via high coating hardness and corrosion inertness. An improved DLC coating process or an improved DLC coating as described in this disclosure reduces WLG drift from the current value of, for example, 20nm per 1 million substrate passes to below 15nm per million substrate passes. DLC coatings as depicted herein may also improve flatness degradation, for example from mechanical wear. For example, flatness degradation may also be reduced from 10nm per 1 million substrate passes to below 7nm per 1 million substrate passes.

According to an embodiment, flatness degradation occurs due to non-uniform wear of the DLC coating caused by a large number of substrate clamping and de-clamping. The mechanics of the process impose higher lateral displacements on the periphery of the substrate holder WT, thus causing higher edge wear. Such non-uniform wear of the coating is responsible for the degradation and flatness of the substrate holder, reducing process yield and resulting in the need for earlier replacement of the substrate holder and machine downtime. As such, the coating process should be tailored to produce a coating composition with high hardness and wear resistance properties to minimize edge wear and maximize substrate holder WT life.

According to embodiments, a low coefficient of friction is required to minimize WLG. Most commercially available coatings (e.g., DLC coatings) can meet specifications during their early stages of use on WT burls. However, increasing the number of substrate passes removes the top surface roughness of the burls, thus causing the substrate to adhere to the substrate WT via, for example, van der waals and capillary forces. This chemical adhesion of the substrate to the top surface of the burls causes an increase in the coefficient of friction and WLG. The increase in WLG translates directly into an overlay problem, reducing process yield and forcing an earlier replacement of the substrate holder WT in the field.

The present disclosure describes an improved coating composition and manner to coat a substrate holder. For example, coating may be performed using a parallel plate plasma enhanced chemical vapor deposition (PE-CVD) reactor. The current setup for PE-CVD is an RF power of about 1500W for the RF electrode and a hexane gas flow of 300sccm or greater. However, with such a process, existing a-c H DLC coatings have a hardness of about 21GPa or less, and a corrosion rate of 2.7nm/H or more. According to the present embodiment, an improved coating hardness of 23GPa or more and a corrosion rate of 1.1nm/h or less are obtained.

In an embodiment, a manufacturing process for coating a substrate is described in further detail below with reference to fig. 4. Through a series of experiments, it has been found that reducing the RF power increases the corrosion resistance of the film for a given gas flow rate when hexane is used as the source gas. Moreover, when this reduction in RF power is coupled with a reduction in gas flow rate, the resulting film will have excellent corrosion resistance as well as high hardness values. As discussed herein, the substrate holder WT comprises a plurality of burls (see, e.g., fig. 3B) protruding from the substrate holder and each burl has a distal surface configured to engage a substrate.

In an embodiment, operation P401 includes applying a coating of an abrasion resistant material at a distal surface of one or more of the plurality of burls via plasma enhanced chemical vapor deposition. In an embodiment, operation P401 includes several sub-operations, such as P403 and P405.

In an embodiment, operation P403 includes adjusting a Radio Frequency (RF) power of the RF electrode in a range of 100W to 1000W for generating the plasma. In an embodiment, operation P403 comprises exposing the one or more plurality of burls to a precursor gas at a gas flow rate of between 20 seem to 300 seem (e.g., 20 to 200 seem) in the chamber, the precursor gas being hexane. In an embodiment, the chamber has a geometry described with respect to the distance between different components inside the chamber. For example, the distance or diameter inside the chamber (see, e.g., D1 in fig. 5), the distance between the top of the chamber and the turntable TT (see, e.g., D2 in fig. 5), the distance between the substrate holder and the gas distribution line (see, e.g., D3 in fig. 5), or other suitable geometric measurement. In an example, in fig. 5, distance D1 may be about 23 inches, distance D2 may be about 6 inches, and distance D3 may be about 5.25 inches. It will be appreciated that the geometry of the chamber is presented by way of example and that other geometries of the chamber may be used.

In an embodiment, the operation P401 of applying the coating further comprises adjusting one or more process parameters comprising at least one of: in a chamber in which a substrate holder is placed at 1X 10 ^-3 To 5X 10 ^-2 Vacuum level in the mbar range; or a turntable speed of a table on which the substrate holder is placed in a range of 5rpm to 100 rpm.

In an embodiment, the coating of wear resistant material is such that the distal surface of the one or more plurality of burls further has at least one of the following properties: a coefficient of friction of the resulting coating in the range of 0.05 to 0.5; a surface of the resulting coating having high spots of less than 10nm and a thickness uniformity of a plurality of burls across the entire substrate holder in the range of up to and down to 10% of the coating thickness of a diameter of 300mm or less; or a wafer loading grid in the range of 0.1nm to 1.5nm, the wafer loading grid being a relative positioning error of the substrate with respect to a reference.

In an embodiment, the wear resistant material is one of Diamond Like Carbon (DLC). In an embodiment, the DLC comprises: (i) DLC doped with B, N, si, O, F, S; and/or (ii) a metal-doped DLC doped with Ti, ta, cr, W, fe, cu, nb, zr, mo, co, ni, ru, al, au or Ag. In an embodiment, a combination of DLC materials may be used to form the wear resistant material.

In an embodiment, the coating of wear resistant material is such that the distal surface of the one or more burls has a hardness property in a range of 20GPa to 27GPa, and a corrosion rate property in a range of 0.1nm/hr to 1.5nm/hr, the corrosion rate being characterized by chronoamperometry in a three-electrode electrochemical cell having an approximately +2.5V potential difference between the working electrode and the counter electrode and the potential difference being applied relative to the reference electrode in a dilute NaCl solution. The coating using hexane may comprise 50 to 65% sp ³ And 25 to 35% hydrogen.

In an embodiment, the hardness is measured by a nanoindentation method, where the measurement is performed using a glass (berkovich) diamond indenter using a nanodma transducer and the indentation depth is kept below 10% of the coating thickness. In an embodiment, the coating has a thickness between 200nm and 3 microns.

In an embodiment, the method 400 further includes an operation P410, the operation P410 including cleaning the plurality of burls with argon (Ar) gas prior to applying the coating. In an embodiment, the cleaning step includes generating a plasma with an Ar gas at an RF power of about 1000W; the Ar gas flow rate was adjusted between 75sccm for 100 seconds. In an embodiment, the method 400 further comprises gradually decreasing the Ar flow rate while increasing the hexane flow rate; and gradually tuning the RF power between 100W to 1000W for applying the coating.

In an embodiment, the method 400 may be performed for different precursor gases (e.g., acetylene gas) and process settingsAs discussed below. For example, the method 400 may be modified as follows. Operation P401 comprises applying a coating of an abrasion resistant material at the distal surface of one or more of the plurality of burls via plasma enhanced chemical vapor deposition. The applying of the coating includes (e.g., modification at operation P403) adjusting a Radio Frequency (RF) power of an RF electrode in a range of 50W to 750W for generating a plasma; and exposing one or more of the plurality of burls to a precursor gas that is acetylene with a gas flow rate between 10sccm to 100sccm in the chamber (e.g., the modification at operation P405). In an embodiment, the coating using acetylene results in a coating having a relatively high hardness (compared to hexane), for example a hardness of greater than 25GPa to 35GPa, and a corrosion resistance between 0.1nm/hr and 2nm/hr may be achieved. The coating with acetylene may comprise 60% to 80% sp% ³ And 20% to 30% hydrogen.

In an embodiment, the application of the coating may further comprise adjusting one or more process parameters, the one or more process parameters comprising at least one of: a vacuum level of the chamber in which the substrate holder is placed, the vacuum level being 1 x 10 ^-3 mbar to 5X 10 ^-2 In the mbar range; or a table on which the substrate holder is placed, the turntable speed being in the range of 5rpm to 100 rpm. In an embodiment, the coating of the wear resistant material is such that the distal surface of one or more burls of the plurality of burls further has at least one of the following properties: the coefficient of friction of the resulting coating, which is in the range of 0.05 to 0.5; a surface of the resulting coating having high spots of less than 10nm and a thickness uniformity of the plurality of burls across the substrate holder in a range of up to and down to 10% of a coating thickness of a diameter of 300mm or less; or a wafer loading grid in the range of 0.1nm to 1.5nm, the wafer loading grid being a relative positioning error of the substrate with respect to a reference.

In an embodiment, the method 400 may be modified such that a first coating using hexane as the precursor gas, as previously described, and a second coating using acetylene as a precursor gas, as previously described, are applied at the distal surface of one or more of the plurality of burls. For example, referring to fig. 3B, the first coating layer may include a coating layer using hexane, and the second coating layer may include a coating layer using acetylene. A coating using hexane as a precursor gas may be applied at a distal surface of one or more of the plurality of burls and a second coating using hexane as a precursor gas may be applied over the first coating. In one example, the method 400 can include applying a first coating of an abrasion resistant material at the distal surface of one or more of the plurality of burls via plasma enhanced chemical vapor deposition. Applying the first coating may include adjusting a Radio Frequency (RF) power of an RF electrode in a range of 100W to 1000W for generating a plasma; and exposing one or more burls of the plurality of burls to a precursor gas at a gas flow rate between 20sccm to 300sccm in the chamber, the precursor gas being hexane. The first layer may include features similar to those of the coating using hexane previously described. The method 400 may further include applying a second coating of an abrasion-resistant material at a distal surface of one or more of the plurality of burls (e.g., to the first coating) via plasma-enhanced chemical vapor deposition. Applying the second coating may include adjusting a Radio Frequency (RF) power of an RF electrode in a range of 50W to 750W for generating a plasma; and exposing one or more of the plurality of burls to a precursor gas at a gas flow rate between 10sccm to 100sccm in the chamber, the precursor gas being acetylene. The second coating may include features similar to those of the previously described coating using acetylene.

In an embodiment, the method 400 may be modified to provide a precursor gas selected from the group consisting of: cyclohexane, n-hexane, or a mixture of carbon-rich and hydrogen-rich gases. For example, the mixture of carbon-rich and hydrogen-rich gas includes at least one of: acetylene and methane, acetylene and hexane, acetylene and cyclohexane, or acetylene and hydrogen. Depending on the precursor gas, the process parameters of the PE-CVD may be adjusted such that burls with a coating having a hardness of more than 21GPa and a corrosion resistance between 0.1nm/hr and 2nm/hr may be achieved.

In an embodiment, the coating of wear resistant material includes, but is not limited to, diamond, WC, crN, and TiN. The coatings described above can be deposited on various types of ceramic or glass substrates, including but not limited to Si, CVD-Si SiC, siSiC, CVD-SiC, microcrystalline glass (zerodur), ULE, fused silica, BK-7, and Corning XG glass substrates, by depositing thin adhesion layers such as Cr, crN, and other coatings with known good adhesion to DLC coatings.

Fig. 5 illustrates an example reactor 500 for performing a plasma enhanced chemical vapor deposition process to apply a coating on a substrate holder. The PE-CVD process requires a tight control of a number of parameters to achieve the desired coating properties. For example, the control parameters include (but are not limited to) pressure P, airflow, exhaust excitation frequency f, power P. During deposition, the overall plasma parameters generally control the rate at which chemically reactive molecular fragments-radicals and energetic species such as electrons and ions are generated and accelerated under electrical potential toward the substrate surface exposed to the plasma. Even for relatively simple gas mixtures, several plasma reactions occur and several new coating species are generated. However, most of the reaction rates are not readily available, making theoretical modeling of the process inefficient and inaccurate. Thus, experimental methods for process optimization are employed to determine process recipes that produce the desired material properties.

In fig. 5, the PE-CVD reactor 500 comprises a chamber CBR in which PE-CVD is performed on a substrate holder WT. The substrate holder WT is placed on the turntable TT. The velocity of the turntable TT is controlled during the coating process of the substrate holder WT. The chamber CBR also contains a plasma generated therein. In an embodiment, the plasma is generated by controlling the Radio Frequency (RF) power of the RF electrode. For example, the RF power may be between 100W to 1000W, or 50W to 750W.

The chamber CBR comprises a gas distribution line GD via which precursor gases are supplied in the chamber CBR. In embodiments, the gas is hexane, acetylene, or other gases discussed herein. In an example, the gas flow rate of hexane is controlled between 20sccm to 300sccm while the RF power is controlled between 100W to 1000W. In another example, the gas flow rate of acetylene is controlled between 10sccm to 100sccm and the RF power can be between 50W to 750W.

In an embodiment, the reactor 500 may be connected to a vacuum system VS to control the vacuum level of the chamber CBR. In an embodiment, the reactor 500 is connected to a gas inlet through which gases such as argon (Ar) and oxygen (O) may be supplied to the chamber CBR. In an embodiment, a gas may be supplied for cleaning the substrate holder WT before applying the coating on the substrate holder WT.

In an embodiment, the PE-CVD reactor 500 comprises Optical Modulation Spectroscopy (OMS) which may be used to study CVD growth on said substrate holder WT. In an embodiment, the reactor 500 is water-cooled to control the temperature of said turret TT.

In an embodiment, the chamber has the geometry described with respect to the different components inside the chamber. For example, the geometry may be characterized as a distance D1 or diameter D1 inside the chamber, a distance D2 between the top of the chamber and the turntable TT, a distance D3 between the substrate or turntable and the gas distribution line (see D3 in fig. 5), or other suitable geometric measurement. In an example, in fig. 5, distance D1 may be about 23 inches, distance D2 may be about 6 inches, and distance D3 may be about 5.25 inches. It will be appreciated that the geometry of the chamber is presented by way of example and that other geometries of the chamber may be used.

Supporting examples 1, 2 and 3 for process parameters in the PE-CVD process and the resulting coating are discussed below.

In example 1, si and SiSiC substrates (e.g., burls) were coated with a DLC film of about 650nm using hexane as a source gas. This coating pass (run) was performed using a hexane flow rate of 150sccm and an RF power of 750W. The resulting coating is uniform and dense. The hardness of these coatings was measured to be between 23 ± 1.5GPa using a hysitron nanoindenter equipped with a glass diamond indenter at a maximum contact depth of < 50 nm. Furthermore, the corrosion characteristics of these coatings were characterized using chronoamperometry measured in a three-electrode electrochemical cell having a +2.5V potential difference between the working and counter electrodes and applied relative to a reference electrode in dilute NaCl solution. The calculated corrosion rate was determined to be 1.1nm/hr. These values indicate an increase in hardness and corrosion resistance of about 15% and 250%, respectively, when compared to standard DLC coatings deposited using factory set power and gas flow parameters of about 1500W and 300sccm, respectively.

In example 2, si and SiSiC substrates (e.g., burls) were coated with a DLC film of about 650nm using acetylene as a source gas. This coating pass was performed using an acetylene flow rate of 50sccm and an RF power of 300W. The resulting coating is uniform and dense. The hardness of these coatings was measured between 28 ± 1.5GPa using a hysitron nanoindenter equipped with a glass diamond indenter at a maximum contact depth of < 50 nm. Furthermore, the corrosion characteristics of these coatings were characterized using chronoamperometry measured in a three-electrode electrochemical cell having a +2.5V potential difference between the working and counter electrodes and applied relative to a reference electrode in dilute NaCl solution. The calculated etch rate was determined to be 1.6nm/hr. These values indicate an increase in hardness and corrosion resistance of about 40% and 250%, respectively, when compared to standard DLC films deposited using factory set power and gas flow parameters of about 1500W and 300sccm, respectively.

In example 3, si and SiSiC substrates (e.g., burls) were coated with a DLC film of about 650nm using acetylene as a source gas. This coating pass was performed using an acetylene flow rate of 30sccm and an RF power of 150W. The resulting coating is uniform and dense. The hardness of these coatings was measured between 31 ± 1.5GPa using a hysitron nanoindenter equipped with a glass diamond indenter at a maximum contact depth of < 50 nm. Furthermore, the corrosion characteristics of these coatings were characterized using chronoamperometry measured in a three-electrode electrochemical cell having a +2.5V potential difference between the working and counter electrodes and applied relative to a reference electrode in dilute NaCl solution. The calculated etch rate was determined to be 1.6nm/hr. These values indicate an increase in hardness and corrosion resistance of about 40% and 250%, respectively, when compared to standard DLC films deposited using factory set power and gas flow parameters of about 1500W and 300sccm, respectively.

In an embodiment, a substrate holder manufactured according to the method of fig. 4 is provided (see, e.g., fig. 3A and 3B). A substrate holder for use in a lithographic apparatus and configured to support a substrate includes a body (e.g., siSiC) having a body surface, and a plurality of burls projecting from the body surface. In an embodiment, each burl has a distal surface configured to engage with the substrate; the distal surface of the burls is substantially conformal to a support plane and is configured for supporting the substrate; and the distal surface of one or more of the plurality of burls coated with the wear resistant material has a hardness in the range of 20GPa to 27GPa or 25GPa to 35GPa and a corrosion rate in the range of 0.1nm/hr to 2nm/hr measured by chronoamperometry in a three-electrode electrochemical cell having a +2.5V potential difference between the working electrode and the counter electrode and applied relative to the reference electrode in a dilute NaCl solution. In an embodiment, the distal surface has a hardness in a range of 20GPa to 27GPa, and a corrosion rate in a range of 0.1nm/hr to 2 nm/hr.

As previously discussed, the distal surface has a hardness in the range of 25GPa to 35GPa and a corrosion rate in the range of 0.1nm/hr to 1.5 nm/hr. As previously discussed, hardness is measured by, for example, nanoindentation. Measurements were made using a glass diamond indenter using a nano-DMA transducer and the indentation depth was kept below 10% of the coating thickness. In an embodiment, the thickness of the coating is between 200nm and 3 microns. In an embodiment, the wear resistant material is one of Diamond Like Carbon (DLC). In an embodiment, the DLC comprises: (i) DLC doped with B, N, si, O, F, S; and/or (ii) a metal-doped DLC doped with Ti, ta, cr, W, fe, cu, nb, zr, mo, co, ni, ru, al, au or Ag.

In an embodiment, the distal surface further has at least one of the following properties: a coefficient of friction of the resulting coating, the coefficient of friction being in the range of 0.05 to 0.5; a surface of the resulting coating having nano-bumps of less than 10nm and a thickness uniformity of the plurality of burls across the substrate holder in a range of up to and down 10% of a coating thickness of a diameter of 300nm or less; or a wafer loading grid in the range of 0.1nm to 1.5nm, the wafer loading grid being the relative positioning error of the substrate with respect to a reference.

Although the concepts disclosed herein may be used to image on substrates such as silicon wafers, it should be understood that the disclosed concepts may be used with any type of lithographic imaging system, such as those used to image on substrates other than silicon wafers.

Embodiments may be further described in the following aspects.

1. A method of producing a substrate holder for use in a lithographic apparatus, the substrate holder comprising a plurality of burls projecting from the substrate holder and each burl having a distal surface configured to engage with a substrate, the method comprising:

applying a coating of a wear-resistant material at a distal surface of one or more of the plurality of burls via plasma enhanced chemical vapor deposition,

the application of the coating comprises:

adjusting a Radio Frequency (RF) power of an RF electrode in a range of 100W to 1000W to generate a plasma; and

the one or more burls are exposed to a precursor gas at a gas flow rate between 20sccm to 300sccm in the chamber, the precursor gas being hexane.

2. The method of aspect 1, wherein the applying of the coating further comprises:

adjusting one or more process parameters, the one or more process parameters including at least one of:

a vacuum level of the chamber in which the substrate holder is placed, the vacuum level being 1 x 10 ^-3 To 5X 10 ^-2 In the mbar range; or

A turntable speed of a table on which the substrate holder is placed, the turntable speed being in a range of 5rpm to 100 rpm.

3. The method of any of aspects 1-2, wherein the coating of wear resistant material is such that the distal surface of the one or more burls further has at least one of the following properties:

a coefficient of friction of the resulting coating, the coefficient of friction being in the range of 0.05 to 0.5;

a surface of the resulting coating having high spots of less than 10nm and a thickness uniformity across the plurality of burls of the substrate holder and within a range of 300nm or less in diameter in the range of up to and down 10% of the coating thickness; or

A wafer loading grid in the range of 0.1nm to 1.5nm, the wafer loading grid being a relative positioning error of the substrate with respect to a reference.

4. The method of any of aspects 1-3, wherein the wear resistant material is diamond-like carbon (DLC).

5. The method of aspect 4, wherein the DLC comprises: (i) DLC doped with B, N, si, O, F, S; and/or (ii) a metal-doped DLC doped with Ti, ta, cr, W, fe, cu, nb, zr, mo, co, ni, ru, al, au or Ag.

6. The method of any of aspects 1-5, wherein the coating of the wear resistant material is such that the distal surface of the one or more burls has hardness properties in a range of 20-27 GPa and corrosion rate properties in a range of 0.1-2 nm/hr, the corrosion rate being measured by potentiostat chronoamperometry at approximately +2.5V in dilute NaCl solution.

7. The method of any of aspects 1-6, wherein the hardness is measured by nanoindentation, wherein the measurement is performed with a glass diamond indenter using a nanoimdma transducer and the indentation depth remains below 10% of the coating thickness.

8. The method of any of aspects 1-7, wherein the coating has a thickness of between 200nm and 3 microns.

9. The method of any of aspects 1 to 8, further comprising:

cleaning the plurality of burls with argon (Ar) gas prior to applying the coating.

10. The method of aspect 9, wherein the cleaning further comprises:

generating plasma using Ar gas at RF power of about 1000W;

the Ar gas flow rate was adjusted between 75sccm for 100 seconds.

11. The method of aspect 10, further comprising:

gradually decreasing the Ar flow rate while increasing the hexane flow rate; and

the RF power was gradually tuned between 100W to 1000W for applying the coating.

12. The method of any of aspects 1-11, wherein the chamber has a geometry characterized by:

a diameter of an interior of the chamber;

the distance between the top of the chamber and the turntable; and/or

The distance between the substrate or turntable and the gas distribution line.

13. A method of producing a substrate holder for use in a lithographic apparatus, the substrate holder comprising a plurality of burls projecting from the substrate holder and each burl having a distal surface configured to engage with a substrate, the method comprising:

the application of the coating comprises:

adjusting a Radio Frequency (RF) power of an RF electrode in a range of 50W to 750W to generate a plasma; and

exposing the one or more burls to a precursor gas at a gas flow rate of between 10sccm to 100sccm in a chamber, the precursor gas being acetylene.

14. The method of aspect 13, wherein the applying of the coating further comprises:

a vacuum level of the chamber in which the substrate holder is placed, the vacuum level being 1 × 10 ^-3 To 5X 10 ^-2 In the mbar range; or

15. The method of any of aspects 13-14, wherein the coating of wear resistant material is such that the distal surface of the one or more burls further has at least one of the following properties:

the coefficient of friction of the resulting coating, which is in the range of 0.05 to 0.5;

a surface of the resulting coating having nano-bumps of less than 10nm and a thickness uniformity across the plurality of burls of the substrate holder and within a range of 300nm or less in diameter in the range of up and down 10% of the coating thickness; or

16. The method of any of aspects 13-15, wherein the wear resistant material is diamond-like carbon (DLC).

17. The method of aspect 16, wherein the DLC comprises: (i) DLC doped with B, N, si, O, F, S; and/or (ii) a metal-doped DLC doped with Ti, ta, cr, W, fe, cu, nb, zr, mo, co, ni, ru, al, au or Ag.

18. The method of any of aspects 13-17, wherein the coating of the wear resistant material is such that the distal surface of the one or more burls has hardness properties in a range of 25GPa to 35GP and corrosion rate properties in a range of 0.1nm/hr to 2nm/hr, the corrosion rate measured by chronoamperometry in a three-electrode electrochemical cell having a potential difference of about +2.5V between a working electrode and a counter electrode and the potential difference applied relative to a reference electrode in a dilute NaCl solution.

19. The method of any of aspects 13-18, wherein the hardness is measured by nanoindentation, wherein the measurement is performed with a glass diamond indenter using a nanoimdma transducer and the indentation depth remains below 10% of the coating thickness.

20. The method of any of aspects 13-19, wherein the coating has a thickness of between 200nm and 3 microns.

21. The method of any of aspects 13-20, further comprising:

22. The method of aspect 21, wherein the cleaning further comprises:

generating plasma using Ar gas at RF power of about 1000W;

the Ar gas flow rate was adjusted between 75sccm for 100 seconds.

23. The method of aspect 22, further comprising:

24. The method of any of aspects 13-23, wherein the chamber has a geometry characterized by:

a diameter of an interior of the chamber;

the distance between the top of the chamber and the turntable; and/or

The distance between the substrate or turntable and the gas distribution line.

25. A substrate holder for use in a lithographic apparatus and configured to support a substrate, the substrate holder comprising:

a body having a body surface;

a plurality of burls projecting from the body surface, wherein:

each burl having a distal surface configured to engage with the substrate;

the distal surface of the burls is substantially conformal with a support plane and is configured for supporting the substrate; and is

The distal surface of one or more of the plurality of burls coated with the wear resistant material has a hardness in the range of 20GPa to 27GPa or 25GPa to 35GPa and a corrosion rate in the range of 0.1nm/hr to 2nm/hr as measured by chronoamperometry in a three-electrode electrochemical cell having a potential difference of about +2.5V between the working electrode and the counter electrode and applied relative to the reference electrode in a dilute NaCl solution.

26. The substrate holder of any of aspects 25, wherein the distal surface has a hardness in a range of 20GPa to 27GPa and a corrosion rate in a range of 0.1nm/hr to 2 nm/hr.

27. The substrate holder of any of aspects 26, wherein the distal surface has a hardness in a range of 25GPa to 35GPa and a corrosion rate in a range of 0.1nm to 1.5 nm/hr.

28. The substrate holder of any of aspects 25-27, wherein the distal surface further has at least one of the following properties:

a surface of the resulting coating having nano-bumps of less than 10nm and a thickness uniformity across the plurality of burls of the substrate holder within a range of 300nm or less in diameter and within up to and down 10% of a coating thickness; or

29. The substrate holder of any of aspects 25-28, wherein the hardness is measured by nano-indentation using a nano DMA transducer with a glass diamond indenter and the indentation depth remains below 10% of the coating thickness.

30. The method of any of aspects 25-29, wherein the coating has a thickness of between 200nm and 3 microns.

31. The substrate holder of any of aspects 25-30, wherein the wear resistant material is one of diamond-like carbon (DLC).

32. The substrate holder of aspect 31, wherein the DLC comprises: (i) DLC doped with B, N, si, O, F, S; and/or (ii) a metal-doped DLC doped with Ti, ta, cr, W, fe, cu, nb, zr, mo, co, ni, ru, al, au or Ag.

33. A method of producing a substrate holder for use in a lithographic apparatus, the substrate holder comprising a plurality of burls projecting from the substrate holder and each burl having a distal surface configured to engage with a substrate, the method comprising:

applying a first coating of an abrasion resistant material at a distal surface of one or more burls of the plurality of burls via plasma enhanced chemical vapor deposition,

the applying of the first coating comprises:

adjusting a Radio Frequency (RF) power of an RF electrode in a range of 100W to 1000W for generating a plasma; and

exposing one or more of the plurality of burls to a precursor gas at a gas flow rate between 20sccm to 300sccm in a chamber, the precursor gas being hexane;

applying a second coating of an abrasion resistant material at a distal surface of one or more of the plurality of burls via plasma enhanced chemical vapor deposition,

the application of the second coating comprises:

adjusting a Radio Frequency (RF) power of an RF electrode in a range of 50W to 750W for generating a plasma; and

exposing one or more of the plurality of burls to a precursor gas at a gas flow rate between 10sccm to 100sccm in a chamber, the precursor gas being acetylene.

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 as described without departing from the scope of the claims set out below.

Claims

the application of the coating comprises:

2. The method of claim 1, wherein the applying of the coating further comprises:

a vacuum level of the chamber in which the substrate holder is placed, the vacuum level being 1 × 10 ^-3 To 5X 10 ^- ² In the mbar range; or

3. The method of any one of claims 1 to 2, wherein the coating of wear resistant material is such that the distal surface of the one or more burls further has at least one of the following properties:

the coefficient of friction of the resulting coating is in the range of 0.05 to 0.5;

A wafer loading grid, in the range of 0.1nm to 1.5nm, the wafer loading grid being a relative positioning error of the substrate with respect to a reference.

4. Method according to any of claims 1-3, wherein the wear resistant material is Diamond Like Carbon (DLC) and/or the DLC comprises: (i) DLC doped with B, N, si, O, F, S; and/or (ii) a metal-doped DLC doped with Ti, ta, cr, W, fe, cu, nb, zr, mo, co, ni, ru, al, au or Ag.

5. The method of any of claims 1 to 4, wherein the coating of the wear resistant material is such that the distal surface of the one or more burls has hardness properties in the range of 20GPa to 27GPa and corrosion rate properties in the range of 0.1nm/hr to 2nm/hr, the corrosion rate being measured by potentiostat chronoamperometry at about +2.5V in dilute NaCl solution; and/or

Wherein the hardness is measured by nanoindentation with a glass diamond indenter using a nanodMA transducer and with an indentation depth maintained below 10% of the coating thickness.

6. The method of any of claims 1 to 5, further comprising:

cleaning the plurality of burls with argon (Ar) gas prior to applying the coating, wherein the cleaning comprises generating a plasma with the Ar gas at an RF power of about 1000W and adjusting an Ar gas flow rate between 75sccm for 100 seconds;

7. The method of any one of claims 1 to 6, wherein the chamber has a geometry characterized by:

a diameter of an interior of the chamber;

the distance between the top of the chamber and the turntable; and/or

The distance between the substrate or turntable and the gas distribution line.

8. A method of producing a substrate holder for use in a lithographic apparatus, the substrate holder comprising a plurality of burls protruding from the substrate holder and each burl having a distal surface configured to engage with a substrate, the method comprising:

applying a coating of a wear resistant material at a distal surface of one or more of the plurality of burls via plasma enhanced chemical vapor deposition,

the application of the coating comprises:

9. The method of claim 8, wherein the applying of the coating further comprises:

a vacuum level of the chamber in which the substrate holder is placed, the vacuum level being 1 x 10 ^-3 To 5X 10 ^- ² In the mbar range; or

10. The method of any one of claims 8 to 9, wherein the coating of wear resistant material is such that the distal surface of the one or more burls further has at least one of the following properties:

11. The method of any one of claims 8 to 10, wherein the wear resistant material is diamond-like carbon (DLC); and/or the DLC comprises: (i) DLC doped with B, N, si, O, F, S; and/or (ii) a metal-doped DLC doped with Ti, ta, cr, W, fe, cu, nb, zr, mo, co, ni, ru, al, au or Ag.

12. The method of any of claims 8 to 11, wherein the coating of the wear resistant material is such that the distal surface of the one or more burls has hardness properties in a range of 25GPa to 35GP and corrosion rate properties in a range of 0.1nm/hr to 2nm/hr, the corrosion rate measured by chronoamperometry in a three-electrode electrochemical cell having an approximately +2.5V potential difference between a working electrode and a counter electrode and the potential difference applied relative to a reference electrode in a dilute NaCl solution; and/or

13. The method of any of claims 8 to 12, further comprising:

cleaning the plurality of burls with argon (Ar) gas prior to applying the coating, wherein the cleaning further comprises generating a plasma at an RF power of about 1000W using the Ar gas and adjusting an Ar gas flow rate between 75sccm for 100 seconds;

14. The method of any one of claims 8 to 13, wherein the chamber has a geometry characterized by:

a diameter of an interior of the chamber;

the distance between the top of the chamber and the turntable; and/or

The distance between the substrate or turntable and the gas distribution line.

15. A substrate holder for use in a lithographic apparatus and configured to support a substrate, the substrate holder comprising:

a body having a body surface;

a plurality of burls projecting from the body surface, wherein:

each burl having a distal surface configured to engage with the substrate;

The distal surface of one or more of the plurality of burls coated with the wear resistant material has a hardness in the range of 20GPa to 27GPa or 25GPa to 35GPa and a corrosion rate in the range of 0.1nm/hr to 2nm/hr measured by chronoamperometry in a three-electrode electrochemical cell having a potential difference of about +2.5V between the working electrode and the counter electrode and applied relative to the reference electrode in a dilute NaCl solution.