Method of substrate support repair

Abstract

A method of joining a support member to a substrate support, the method comprising: inserting the support member into a recess in the substrate support with a bonding material between facing surfaces of the support member and the substrate support; and applying a bonding temperature and a bonding pressure to the bonding material, wherein the bonding material comprises a first material and a second material, wherein the first material comprises a powder of an oxalate, and the second material comprises nanoparticles.

Description

METHOD OF SUBSTRATE SUPPORT REPAIRCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority of EP application 23214448.5 which was filed on 5 December 2023 and which is incorporated herein in its entirety by reference.FIELD

[0002] The present invention relates to a method of joining a support member to a substrate support, a method of substrate support repair and to a substrate support.BACKGROUND

[0003] A lithographic apparatus is a machine constructed to apply a desired pattern onto a substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). A lithographic apparatus may, for example, project a pattern (also often referred to as “design layout” or “design”) of a patterning device (e.g., a mask) onto a layer of radiation- sensitive material (resist) provided on a substrate (e.g., a wafer).

[0004] As semiconductor manufacturing processes continue to advance, the dimensions of circuit elements have continually been reduced while the amount of functional elements, such as transistors, per device has been steadily increasing over decades, following a trend commonly referred to as “Moore’s law”. To keep up with Moore’s law the semiconductor industry is chasing technologies that enable to create increasingly smaller features. To project a pattern on a substrate a lithographic apparatus may use electromagnetic radiation. The wavelength of this radiation determines the minimum size of features which are patterned on the substrate. Typical wavelengths currently in use are 365 nm (i-line), 248 nm, 193 nm and 13.5 nm.

[0005] A lithographic apparatus may include an illumination system for providing a projection beam of radiation, and a support structure for supporting a patterning device. The patterning device may serve to impart the projection beam with a pattern in its cross-section. The apparatus may also include a projection system for projecting the patterned beam onto a target portion of a substrate.

[0006] In a lithographic apparatus, the substrate to be exposed (which may be referred to as a production substrate) may be held on a substrate support. The substrate support may be supported on a stage. The substrate support includes a substrate -facing surface of a main body and a stage-facing surface opposite the substrate-facing surface. Grooves may be formed in the stage-facing surface of the main body of the substrate support. Fluid flow through the grooves may be used to provide negative pressure, for example such that the grooves act as vacuum channels, which may aid in securing the substrate support to the stage. There may be a plurality of through holes in the grooves extending to the substrate-facing side of the substrate support. The plurality of through holes enable the flow to provide negative pressure to aid in securing the substrate to the substrate support.

[0007] The substrate support may comprise a plurality of protrusions (or support members) which support the substrate. These protrusions may need to be repaired or replaced, as the protrusions may become damaged in use.

[0008] Repair of protrusions is a cumbersome, complicated process. This is because protrusions are small in size.

[0009] In addition, high temperatures are typically required to adhere a new protrusion to the substrate support. High temperatures may lead to undesired changes in the substrate support (such as a change in flatness or in roughness of the substrate support). Furthermore, high temperatures may lead to damage of the substrate support.

[0010] Therefore, there is a need to provide a simple process for joining a support member to a substrate support which does not utilise high temperatures.

[0011] When two surfaces are joined (bonded) a bond is formed between them. Two important parameters of a bond are the adhesive strength of the bond and the cohesive strength of the bond. In addition to other parameters, the adhesive strength and the cohesive strength are important to consider when designing a strong adhesive bond. The adhesive strength is the strength of a bond at the interface between the bonding material and a substrate. The cohesive strength refers to the strength of the bulk of the bonding material.

[0012] Known methods of repairing a substrate support result in a bond having either poor adhesive strength and / or poor cohesive strength. Poor adhesive strength of a bond can lead to delamination. Poor cohesive strength can lead to a weak bonding layer which degenerated total bond stability.

[0013] In addition, it is desirable to minimise the complexity of repairing a substrate support. It is desirable to have a bonding technology that reduces or eliminates the need for adhesive layers.

[0014] KR20210035991 discloses a method for repairing a working stage having a plurality of substrate supporting protrusions using an UV photosensitive liquid cured by ultraviolet irradiation. The UV photosensitive liquid may contain silver nanowires or metal nanoparticles.

[0015] JP2008028052A discloses a repairing method of electrostatic chuck electrode having protrusions thereon by thermal spraying an insulator in the recess to remove a damaged area.

[0016] There is a need to provide a convenient method of joining a support member to a substrate support which forms a strong bond and overcomes the problems discussed above.SUMMARY

[0017] According to an aspect of the present disclosure there is provided a method of joining a support member to a substrate support, the method comprising: inserting the support member into a recess in the substrate support with a bonding material between facing surfaces of the support member and the substrate support; and applying a bonding temperature and a bonding pressure to the bonding material, wherein :the bonding material comprises a first material and a second material, wherein the first material comprises a powder of an oxalate, and the second material comprises nanoparticles.

[0018] According to an aspect of the present disclosure, there is provided a method of repairing a substrate support, the method comprising: forming a recess at a target location, and joining a support member to the substrate support at the target location using the method of any preceding claim.

[0019] According to an aspect of the present disclosure, there is provided a substrate support comprising a plurality of support members protruding from a surface thereof, wherein the substrate support is produced by repairing a substrate support using the method of the present disclosure.

[0020] According to an aspect of the present disclosure, there is provided a substrate support comprising silicon or a compound of silicon, the substrate support comprising: at least one support member protruding from a surface thereof, the support member comprising silicon or a compound of silicon; and a connecting body disposed between the substrate support and the support member, the connecting body comprising the following layers in sequence: a first layer comprising silicon oxalate; a second layer comprising silver; and a third layer comprising silicon oxalate.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Embodiments of the invention will now be described by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:Figure 1 schematically depicts an overview of a lithographic apparatus;Figure 2 depicts a plan view of a substrate support;Figure 3 depicts a cross-sectional view of the substrate support of Figure 2;Figures 4A and 4B show a schematic of a joining method. Figures 4C is a schematic representation of a fractured bond formed, the bond having been formed by the method shown on Figures 4A-4B;Figures 5 A and 5B show a schematic of a joining method. Figures 5C is a schematic representation of a fractured bond formed, the bond having been formed by the method shown on Figures 5A-5B;Figures 6A and 6B show a schematic of a joining method according to the present disclosure. Figures 6C is a schematic representation of a fractured bond formed, the bond having been formed by the method shown on Figures 6A-6B;Figure 7 shows a microstructure of a cross section of a stack formed by the joining method shown on Figures 4 A and 4B;Figure 8 shows a microstructure of a cross section of a stack formed by the method shown on Figures 5A and 5B;Figure 9 shows a microstructure of a cross section of a stack formed by a joining method according to the present disclosure;Figure 10A shows a schematic of cross-section of a substrate support and support member prior to bonding. Figure 10B shows a substrate support and a support member after bonding.;Figure 11 shows a schematic of a cross-section of a substrate support.

[0023] The features shown in the figures are not necessarily to scale, and the size and / or arrangement depicted is not limiting. It will be understood that the figures include optional features which may not be essential to the invention. Furthermore, not all of the features of the substrate support are depicted in each of the figures, and the figures may only show some of the components relevant for describing a particular feature.DETAILED DESCRIPTION

[0024] In the present document, the terms “radiation” and “beam” are used to encompass all types of electromagnetic radiation, including ultraviolet radiation (e.g. with a wavelength of 436, 405, 365, 248, 193, 157, 126 or 13.5 nm).

[0025] The term “reticle”, “mask” or “patterning device” as employed in this text may be broadly interpreted as referring to a generic patterning device that can be used to endow an incoming radiation beam with a patterned cross-section, corresponding to a pattern that is to be created in a target portion of the substrate. The term “light valve” can also be used in this context. Besides the classic mask (transmissive or reflective, binary, phase- shifting, hybrid, etc.), examples of other such patterning devices include a programmable mirror array and a programmable LCD array.

[0026] Figure 1 schematically depicts a lithographic apparatus LA. The lithographic apparatus includes an illumination system (also referred to as illuminator) IL configured to condition a radiation beam B (e.g., EUV radiation or DUV radiation), a mask support (e.g., a mask table) MT constructed to support a patterning device (e.g., a mask) MA and connected to a first positioner PM configured to accurately position the patterning device MA in accordance with certain parameters, a substrate table (e.g., a support table or a substrate support) WT constructed to hold a substrate (e.g., a resist coated wafer) W and connected to a second positioner PW configured to accurately position the substrate table WT in accordance with certain parameters, and a projection system (e.g., a refractive projection lens system) PS configured to project a pattern imparted to the radiation beam B by patterning device MA onto a target portion C (e.g., comprising one or more dies) of the substrate W. The substrate table WT may optionally comprise a substrate support or a substrate holder (not shown in Figure 1) constructed to hold the substrate W.

[0027] In operation, the illumination system IL receives the radiation beam B from a radiation source SO, e.g. via a beam delivery system BD. The illumination system IL may include various types of optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic, and / or other types of optical components, or any combination thereof, for directing, shaping, and / or controlling radiation. The illuminator IL may be used to condition the radiation beam B to have a desired spatial and angular intensity distribution in its cross section at a plane of the patterning device MA.

[0028] The term “projection system” PS used herein should be broadly interpreted as encompassing various types of projection system, including refractive, reflective, catadioptric, anamorphic, magnetic, electromagnetic and / or electrostatic optical systems, or any combination thereof, as appropriate for the exposure radiation being used, and / or for other factors such as the use of an immersion liquid or the use of a vacuum. Any use of the term “projection lens” herein may be considered as synonymous with the more general term “projection system” PS.

[0029] The lithographic apparatus may be of a type wherein at least a portion of the substrate W may be covered by an immersion liquid having a relatively high refractive index, e.g., water, so as to fill an immersion space between the projection system PS and the substrate W - which is also referred to as immersion lithography. More information on immersion techniques is given in US 6,952,253, which is incorporated herein by reference.

[0030] The lithographic apparatus may be of a type having two or more substrate tables WT (also named “dual stage”). In such “multiple stage” machine, the substrate tables WT may be used in parallel, and / or steps in preparation of a subsequent exposure of the substrate W may be carried out on the substrate W located on one of the substrate table WT while another substrate W on the other substrate table WT is being used for exposing a pattern on the other substrate W.

[0031] In addition to the substrate table WT, the lithographic apparatus may comprise a measurement stage (not depicted in Figure 1). The measurement stage is arranged to hold a sensor and / or a cleaning device. The sensor may be arranged to measure a property of the projection system PS or a property of the radiation beam B. The measurement stage may hold multiple sensors. The cleaning device may be arranged to clean part of the lithographic apparatus, for example a part of the projection system PS or a part of a system that provides the immersion liquid. The measurement stage may move beneath the projection system PS when the substrate table WT is away from the projection system PS.

[0032] In operation, the radiation beam B is incident on the patterning device, e.g. mask, MA which is held on the mask support MT, and is patterned by the pattern (design layout) present on patterning device MA. Having traversed the mask MA, the radiation beam B passes through the projection system PS, which focuses the beam onto a target portion C of the substrate W. With the aid of the second positioner PW and a position measurement system PMS, 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 at a focused and aligned position. Similarly, the first positioner PM and possibly another position sensor (which is not explicitly depicted in Figure 1) may be used to accurately position the patterning device MA with respect to the path of the radiation beam B. Patterning device MA and substrate W may be aligned using mask alignment marks Ml, M2 and substrate alignment marks Pl, P2. Although the substrate alignment marks Pl, P2 as illustrated occupy dedicated target portions, they may be located in spaces between target portions. Substrate alignment marks Pl, P2 are known as scribe-lane alignment marks when these are located between the target portions C.

[0033] In this specification, a Cartesian coordinate system is used. The Cartesian coordinate system has three axes, i.e., an x-axis, a y-axis and a z-axis. Each of the three axes is orthogonal to the other two axes. A rotation around the x-axis is referred to as an Rx-rotation. A rotation around the y-axis is referred to as an Ry -rotation. A rotation around about the z-axis is referred to as an Rz-rotation. The x-axis and the y-axis define a horizontal plane, whereas the z-axis is in a vertical direction. The Cartesian coordinate system is not limiting the invention and is used for clarification only. Instead, another coordinate system, such as a cylindrical coordinate system, may be used to clarify the invention. The orientation of the Cartesian coordinate system may be different, for example, such that the z-axis has a component along the horizontal plane.

[0034] In a lithographic apparatus it is necessary to position with great accuracy the upper surface of a substrate to be exposed in the plane of best focus of the aerial image of the pattern projected by the projection system. To achieve this, the substrate can be held on a substrate support. The surface of the substrate support that supports the substrate can be provided with a plurality of burls whose distal ends can be coplanar in a nominal support plane. The burls, though numerous, may be small in cross- sectional area parallel to the support plane so that the total cross-sectional area of their distal ends is a few percent, e.g. less than 5%, of the surface area of the substrate. The gas pressure in the space between the substrate support and the substrate may be reduced relative to the pressure above the substrate to create a force clamping the substrate to the substrate support.

[0035] A plan view of a substrate support 1 is shown in Figure 2. A partial cross section of the substrate support 1 is depicted in Figure 3. The substrate support 1 may be a separate component of or integral with the substrate table WT shown in Figure 1. The substrate support 1 may comprise a main body 10 having an upper surface 11. The main body 10 may form a substantial portion of the substrate support 1. The upper surface 11 may be a top surface of the main body 10 when positioned as shown in Figure 3. That is, the upper surface 11 may be top surface in the Z-direction (the vertical direction).

[0036] The substrate support 1 may comprise a plurality of burls (or protrusions) 20 connected to, and protruding from, the upper surface 11 of the main body 10. Optionally, the substrate support 1 may comprise a plurality of burls (or protrusions or support members) 20 connected to, and protruding from, the lower surface (opposite the upper surface 11) of the main body 10. The plurality of burls 20 may have proximal ends 21, which are situated near the main body 10 when in position, and distal ends 22. The distal ends 22 may be at opposite ends of the plurality of burls 20 to the proximal ends 21. That is, the distal ends 22 may be situated at an end of the burl 20 away from the main body 10.

[0037] The plurality of burls 20 may have a central longitudinal axis 23, with the proximal end 21 at one end of the burl 20 and the distal end 22 at the other end of the burl 20 along the central longitudinal axis 23. Thus, each of the plurality of burls 20 may have a central longitudinal axis 23 from the proximal end 21 to the distal end 22.

[0038] The distal ends 22 of the plurality of burls 20 form a support plane for a substrate W. Specifically, the distal ends 22 of the plurality of burls 20 may support a lower surface 31 of the substrate W. An upper surface 32 of the substrate W may be a surface opposite the lower surface 31. The upper surface 32 may be a surface which is configured to receive the radiation beam B.

[0039] The support plane may be formed in a substantially flat plane. Consequently, the substrate W can be positioned on the support plane to also be substantially flat, which can reduce errors in the pattern printed onto the substrate W (i.e., defectivity).

[0040] As shown in Figure 3, the plurality of burls 20 may be substantially frusto-conical, i.e. a truncated cone, or may be conical in shape. They may instead be substantially cylindrical. A frustoconical burl 20 may be stronger than a cylindrical burl 20 and thus have less likelihood of breaking. Preferably the plurality of burls 20 have the same shape as each other.

[0041] The plurality of burls 20 may be connected to the upper surface 11 of the main body 10 in any suitable way. The plurality of burls 20 may be separate components which are attached to the upper surface 11 of the main body 10. Alternatively, the plurality of burls 20 may be integral to the main body 10. In other words, the plurality of burls 20 may be formed as protrusions from the upper surface 11 of the main body 10, i.e. the plurality of burls 20 may be formed as a single part with the main body 10.

[0042] The substrate support 1 may be configured to enable fluid to be extracted from between the substrate W supported on the support plane and the upper surface 11. Fluid at the edge of the substrate W may be drawn under the substrate W. As fluid is extracted the pressure beneath the substrate W is reduced relative to pressure above the substrate W, and the edge of the substrate W will lower towards the substrate support 1. The substrate W can be clamped by extracting fluid in the space below the substrate W to provide a reduced relative pressure in the space between the substrate support 1 and the substrate W.

[0043] Substrate support 500 referred to in Figures 4A-4C, 5A-5C, 6A-6C, 10 and 11 may be the substrate support 1 described with reference to Figure 3.

[0044] The main body 10 may comprise at least one extraction opening 12 through which the fluid is extracted. There may be a plurality of extraction openings 12.

[0045] It is beneficial to reduce leakage of fluid into the space between the substrate W and the main body 10 when the substrate W is clamped. Therefore, it may be beneficial to provide a physical boundary positioned near the edge of the substrate support 1. The physical boundary could be formed towards an edge of the main body 10 as shown in Figures 2 and 3. The physical boundary could be formed by a sealing member 40. The sealing member 40 may be a wall type protrusion formed around the edge of the main body 10, for example, around the circumference of the main body 10. The sealing member 40 may be formed to provide a seal between the lower side, e.g., lower surface 31, of the substrate W and the substrate support 1 around the edge of the substrate W. The sealprovided by the sealing member 40 need not be a perfect seal but may be a partial seal that reduces but does not eliminate flow of fluid into the space between the substrate support 1 and substrate W.

[0046] The sealing member 40 may surround the plurality of burls 20. The sealing member 40 may protrude from the upper surface 11 of the main body 10. The sealing member 40 may be connected to the main body 10 in any way. The sealing member 40 may be integral with the main body 10.

[0047] A pressure sensor (not depicted in the drawings) may be used to measure the pressure between the substrate W and the upper surface 11 of the main body 10. Various sensors for measuring the pressure in the space below the substrate W are known. For example, a pressure sensor as disclosed in WO 2017 / 137129 Al, which is hereby incorporated by reference in its entirety, provides an example of an appropriate pressure sensor which might be used.

[0048] A flow rate sensor (not depicted in drawings) may be used to measure the flow rate of the fluid extracted via the extraction opening 12. Various sensors for measuring the flow rate from the space below the substrate W are known.

[0049] As mentioned in the introductory part of the description, the protrusions (burls 20) may become damaged during use, meaning that there exists a problem of providing a suitable method of repairing a protrusion or providing a new support member in place of the damaged protrusion. Preferably, the method must be convenient, avoid high temperatures and result in a bond with high adhesive and high cohesive strength. In addition, it may be preferable that a bond which is formed between the support member and the substrate support during repair does not change the thermal conductivity of the substrate support.

[0050] The term support member may be used to mean a protrusion (burl) of a substrate support, or may be used to refer to a component which is being joined to a substrate support to form the protrusion of the substrate support.

[0051] It is known that it may be possible to reduce the temperature at which the support member is joined to a substrate support by using metal nanoparticles as a bonding material. Nanoparticles show a reduced melting temperature compared to their bulk counterparts.

[0052] Therefore, that it may be possible to join a support member to a substrate support by melting a layer of nanoparticles which are disposed at an interface between a support member and a substrate support. A schematic of an example of this method is shown on Figures 4A-4C.

[0053] According to this method, a support member 100 is adhered to a substrate support 500 by applying a layer of nanoparticles 303 to the interface between support member 100 and substrate support 500. As nanoparticles 303 have a melting temperature which is less than the melting temperature of their bulk counterparts, applying a temperature which is less than the melting temperature of bulk material may cause the nanoparticles 303 to melt. Upon cooling, the melted nanoparticles 303 solidify to form a bonding layer 300. Therefore, a support member 100 may be joined to a substrate support 500without applying high temperatures.

[0054] For example, silver nanoparticles have a reduced melting temperature compared to bulk silver (the melting temperature of silver nanoparticles depends on their diameter, so the melting point can be reduced to temperatures below 450°C for diameters below 100 nm), whereas bulk silver has a constant melting temperature of 961.8°C). Therefore, applying a temperature of 450°C causes silver nanoparticles to melt. Upon cooling, a bonding layer 300 comprising elemental silver is formed.

[0055] The method illustrated in Figures 4A-4B may be performed with a support member 100 and a substrate support 500 which are formed from SiSiC (sintered silicon carbide). According to this embodiment, it has been found that the adhesive strength of a bonding layer 300 comprising elemental silver bond formed by the method shown is poor, and that the bond delaminates upon application of a relatively low shear force F. Accordingly, upon application of shear force F, the structure formed according to this joining method may delaminate as shown in Figure 4C.

[0056] However, the adhesive strength of bonding layer 300 would be relatively low if the support member 100 and the substrate support 500 were formed of another material, such as silicon carbide (SiC) or elemental silicon. This problem would also be observed if the nanoparticles 303 were not silver nanoparticles, and were silicon nanoparticles for example. Therefore, joining a support member 100 to a substrate support 500 according to the method shown on Figures 4A-4B may result in low adhesive strength.

[0057] An example of a cross-section of a structure formed by this method is shown on Figure 7. The micrograph shown on Figure 7 was obtained via optical microscopy. The resulting micro structure reveals that the support member 100 and substrate support 500 are joined by bonding layer 300 comprising elemental silver. The features seen between bonding layer 300 and substrate support 500 approximately in the centre of Figure 7 are due to an uneven surface of the substrate support 500, and do not represent any specific features of a bond formed by the method described with reference to Figures 4A-4C.

[0058] An alternative known way of joining two surfaces at a relatively low temperature (such as a surface of a support member 100 and a surface of a substrate support 500) by utilising the thermal decomposition of a metal oxalate. A schematic of this method is shown on Figures 5A-5B.

[0059] According to the method shown on Figures 5A-5B, an oxalate powder layer 304 applied between the support member 100 and the substrate support 500. Applying heat to the oxalate powder layer 304 causes the oxalate to decompose and react with a surface of the support member 100 facing the oxalate powder layer 304 and a surface of the substrate support 500 facing the oxalate powder layer 304. As a result, an oxide layer 200 is formed on the surface of the support member 100 and on the surface of the substrate support 500. The oxide layers 200 forms a strong bond with the support member 100 and the substrate support 500, meaning that the adhesive strength of the bond is relatively high.

[0060] The support member 100 and the substrate support 500 may be formed from sintered silicon carbide (SiSiC). The oxalate powder may be silver oxalate powder. Applying heat to the oxalatepowder layer 304 comprising silver oxalate powder causes the silver oxalate to decompose and react with the SiSiC. A relatively low temperature (such as 450°C) can be applied to initiate thermal decomposition of silver oxalate. As a result of this reaction, the oxide layer 200 comprising a layer of silicon oxide is formed on the surface of the support member 100 and on the surface of the substrate support 500. The oxide layers 200 comprising silicon oxide forms a strong bond with the support member 100 and the substrate support 500, meaning that the adhesive strength of the bond is relatively high.

[0061] According to the method shown on Figures 5A-5B, a porous bonding layer 301 is formed between oxide layers 200. In the example comprising silver oxalate powder, the porous bonding layer 301 is formed of elemental silver. The porous bonding layer 301 is porous. Therefore, the porous bonding layer 301 has inhomogeneous properties, leading to locally varying cohesive strengths. As a consequence, the resulting bond between the support member 100 and the substrate support 500 has poor overall bonding strength, and the porous bonding layer 301 fails under application of shear force F as shown in Figure 5C. Application of shear force F may thus result in a mixed fracture of cohesive fracture in the porous bonding layer 301 and fracture of the bulk material of support member 100 and / or substrate 500.

[0062] An example of a cross-section of a structure formed by this method is shown on Figure 8. The resulting microstructure reveals that the support member 100 and substrate support 500 are joined by porous bonding layer 301 which is porous. A oxide layer 200 comprising silicon oxide is formed between the support member 100 and porous bonding layer 301 and another oxide layer 200 comprising silicon oxide is formed between the porous bonding layer 301 and the substrate support 500.

[0063] While the methods described with reference to Figures 4A-4C and Figures 5A-5C refer to examples comprising particular materials, these methods may be performed with other materials, which would result in a bond having similar properties.

[0064] For example, using nanoparticles of a material other than silver may also result in a bonding layer 300 having high cohesive strength but low adhesive strength. Nanoparticles such as silicon nanoparticles may be used.

[0065] For example, the support member 100 and substrate support 500 are not necessarily formed of SiSiC. The support member 100 and substrate support 500 may be formed from a different material which may react in a similar way with an oxalate powder, to form an oxide layer providing a high adhesive strength to a bond.

[0066] The joining methods described with reference to Figures 4A-4C and Figures 5A-5C exhibit certain advantages over the method known in the art, because they are relatively simple and allow for a support member 100 to be bonded to a substrate support 500 at relatively low temperatures.

[0067] However, the method described with reference to Figures 4A-4C shows poor adhesive strength. The method described with reference to Figures 5A-5C shows poor boding strength.

[0068] According to the present disclosure, there is provided a method of joining a support member to a substrate support which utilises the relatively low melting point of nanoparticles in addition to the high adhesive strength provided by a bond formed by thermal decomposition of an oxalate.Accordingly, there is provided a method of joining a support member 100 to a substrate support 500, the method comprising: inserting the support member 100 into a recess 600 in the substrate support 500 with a bonding material 305 between facing surfaces of the support member 100 and the substrate support 500; and applying a bonding temperature and a bonding pressure to the bonding material 305, wherein: the bonding material 305 comprises a first material and a second material, wherein the first material comprises a powder of an oxalate, and the second material comprises nanoparticles.

[0069] An example of a bond formed according to this method is illustrated schematically on Figures 6A-6C.

[0070] According to this method, a bonding material 305 comprising a first material and a second material is provided between the surface of a support member 100 and the surface of a substrate support 500. When a bonding temperature is applied and a bonding pressure is applied to the bonding material 305, a bond comprising a bonding layer 302 is formed between two oxide layers 200. Due to the presence of the first material, oxide layers 200 are formed on the surfaces of the support member 100 and the substrate support 500 respectively. Accordingly, high adhesive strength is achieved. Oxide layers 200 are shown as bold lines on Figures 6A-6B.

[0071] When the second material melts due to application of the bonding temperature, the second material fills the pores which would have been formed in porous bonding layer 301. Accordingly, the bonding layer 302 is formed which is not porous.

[0072] Due to the presence of the second material, the bonding layer 302 formed between the oxide layers 200 is not porous (or is at least less porous than the porous bonding layer 301). Accordingly, cohesive strength of the bond is achieved.

[0073] The bonding temperature depends on various parameters of the system, and may be selected as described below. The bonding pressure depends on various parameters of the system, and may be selected as described below.

[0074] The first material is provided as a power, so that it may be mixed with the second material to form a homogenous mix. The bonding material 305 may be a homogeneous mix so that there is homogeneous contact of particles of the first material with the second material nanoparticles. This may improve the strength of a bond between the support member 100 and the substrate support 500.

[0075] In an embodiment, the oxalate comprises an oxalate of a first element and the nanoparticles comprise nanoparticles of a second element.

[0076] In an embodiment, the first element and the second element are the same.

[0077] In an embodiment, the first element is silver, and the second element is silver.

[0078] In an embodiment, the bonding temperature is greater than a thermal decomposition temperature of the first material. Accordingly, upon application of the bonding temperature, theoxalate begins thermal decomposition. The thermal decomposition of an oxalate of element A may be represented by Formula 1.

[0079] [Formula 1] AXC2O4 xA + CO + O2, wherein x represents the number of atoms of x in accordance with the stoichiometric ratio. O2 reacts with the surface of the support member 100 and the surface of a substrate support 500 to form oxide layers 200 at the interface.

[0080] When the first element is silver and the first material comprises a powder of an oxalate, the thermal decomposition of the silver oxalate may be represented by Formula 2.

[0081] [Formula 2] AgzCzCh — 2Ag + 2CO2

[0082] Thermal decomposition of silver oxalate occurs at temperatures of approximately between 200-250°C.

[0083] While reference is made to silver nanoparticles, the second material is not limited thereto.The second material may comprise silicon nanoparticles. In this case, the bonding material 305 may comprise a powder of an oxalate of element A (A ’zOi) and silicon nanoparticles. In this case, bonding layer 301 may comprise a silicon-rich phase and a phase rich in element A, formed by the thermal decomposition according to Formula 1 and melting of silicon nanoparticles.

[0084] In an embodiment, the powder of the first material is formed of particles having a diameter which is approximately maximal one third of a final bond thickness (i.e. the final bond thickness is the combined thickness of two oxide layers 200 and bonding layer 302). This ensures that a homogeneous thick and smooth bond layer 305 is present prior bonding. Particles that are too large would first, prevent uniform contact between the support member 100 and the bonding layer 305, and second prevent uniform contact between the substrate support 500 and the bonding layer 305. This would reduce the adhesive strength.

[0085] Optionally, the first material comprises a powder formed of particles of approximately 3 pm in diameter or less. However, the size of powder particles may be greater than 3 pm, depending on the desired final bond thickness.

[0086] According to an embodiment, the bonding temperature is a temperature at which the second material of the bonding material is caused to melt. The bonding temperature is selected so that the nanoparticles of the second material melt. After melting, the second material melt solidifies to form the bonding layer 302.

[0087] According to an embodiment, the bonding temperature is equal to or greater than the melting point of the second material.

[0088] Alternatively, the bonding temperature may be lower than the melting point of the second material. This is because thermal decomposition of the oxalate may be an exothermic reaction which releases heat. Therefore, heat provided thermal decomposition of the oxalate may assist in melting the second material. Accordingly, as the oxalate decomposes it releases heat, causing the nanoparticle to melt and make a dense bonding layer 302.

[0089] In an embodiment, the nanoparticles comprise nanoparticles of a diameter equal to or less than 100 nm. It is known that the melting point of nanoparticles (Tmnano is less than that of bulk materials (Tmbuik).

[0090] According to an embodiment in which silver nanoparticles of 100 nm are used, a bonding temperature of 450°C is sufficient to cause the silver nanoparticles to melt. However, using smaller silver nanoparticles (or nanoparticles of the same size but of a lower Tmbuik may not require a temperature as high as 450°C for the nanoparticles to melt and form a bond. Optionally, the bonding temperature may be selected so that no undesirable heat-induced deformations are inflicted on the substrate support 500 by application of the bonding temperature.

[0091] The bonding temperature may be selected as appropriate to cause the nanoparticles to melt, and so the bonding temperature may depend on the second material, the size of the nanoparticles, and / or the amount of heat released by thermal decomposition of the oxalate.

[0092] In an embodiment, the method further comprises, prior to the inserting the support member 100, applying the bonding material 305 to either or both of the facing surfaces of the support member 100 and the substrate support 500, wherein the applied bonding material 305 comprises a solvent.

[0093] By including a solvent in the bonding material 305, the ease of application of a bonding material 305 may be improved. This addition of solvent to the bonding material 305 enables the bonding material 305 to be formed in the form of a paste or a liquid, rather than a powder, which may make it easier to handle. Alternatively, the bonding material 305 does not include a solvent, and the bonding material 305 may be disposed between facing surfaces of the support member 100 and the substrate support 500 as a powder.

[0094] The solvent may be readily available solvent, and may not chemically react with the support member 100 and the substrate support 500 or the constituents of the bonding material 305. Therefore, solvents such as acetone, isopropyl alcohol, ethanol, and others may be used. In an embodiment, the solvent is acetone.

[0095] In an embodiment, the bonding material 305 comprises silver nanoparticles, silver oxalate and acetone. According to this non-limiting embodiment, the constituents of bonding material 305 may be mixed according to the following a weight ratio. According to an example, silver oxalate powder, silver nanoparticle paste and acetone may be mixed in a weight ratio of 1:4:4 (silver oxalate: silver nanoparticles paste:acetone). The nanoparticle paste may be a commercially available paste of silver nanoparticles mixed in a solvent, such as the Conductive Silver Paste, Purity: >99%, average particle size: 80nm, CAS-No. 7440-22-4 available from Intelligent Materials Pvt. Ltd. A cross section of a bonding layer 302 formed according to this method is shown on Figure 9, which is described in detail below. This is one example which can be used as the bonding material 305 in a method according to an embodiment.

[0096] In an embodiment, the inserting the support member 100 into the recess 600 is performed after the solvent has evaporated. The solvent may be partially, substantially or completely evaporated.

[0097] In an embodiment, after the applying the bonding material 305 and prior to the inserting the support member 100 into the recess 600 the method comprises applying an evaporating temperature to the solvent to cause the solvent to evaporate. The evaporating temperature may be any suitable temperature which causes or accelerated solvent evaporation.

[0098] In an example, the evaporation temperature may be room temperatures (such as 20°C or higher and / or 25°C or lower). The evaporation temperature may be selected as appropriate for the solvent being used in the bonding material 305. For example, when the solvent is acetone, applying an evaporation temperature of 20°C or higher or 25°C or lower may be sufficient to cause the solvent to evaporate. Therefore, using acetone as a solvent does not require additional high temperatures to be applied, as room temperature may be sufficient to evaporate the solvent.

[0099] In an embodiment, the evaporating temperature is below 140°C, and preferably, below 100 °C. The evaporating temperature may be relatively low, because higher temperatures than the examples discussed here may not be required to cause partial, substantial or complete evaporation of the solvent. However, the evaporating temperature may be selected as appropriate for a particular solvent (e.g. a higher evaporating temperature may be appropriate for a solvent having a higher boiling point).

[0100] Applying an evaporation temperature may be desirable, because the solvent is not a necessary component for the final bond that is formed, meaning it may be desirable for the solvent to be removed prior to application of bonding temperature and bonding pressure, for example, by evaporation. Applying an evaporating temperature causes the solvent to evaporate. Evaporation of the solvent may also aid even dispersion of the bonding material 305 between the facing surfaces of the support member 100 and the substrate support 500.

[0101] Furthermore, it may not be necessary to apply an evaporation temperature to cause all of the solvent to evaporate. It may be sufficient to cause some of the solvent to evaporate prior to inserting the support member 100 into the recess 600.

[0102] It may not be necessary to apply an evaporation temperature, because the solvent may partially, substantially or fully evaporate upon application of the bonding temperature.

[0103] In an embodiment, the bonding pressure is in the region of equal to or greater than 1 MPa and equal or lower than the compressive strength of bulk substrate material and equal or lower than the compressive strength of the support member. For example, the bonding pressure may be 5 MPa.

[0104] Applying a pressure of less than IMPa may result in increased porosity of the bonding layer 302 and / or of the oxide layers 200. This may result in reduced adhesive and / or cohesive strength of the bond. Therefore, a pressure of IMPa or higher may be applied.

[0105] Applying a pressure which is higher than the compressive strength of bulk substrate material and higher than the compressive strength of the support member 100 may result in the substrate material or support member 100 fracturing (for example, if bonding pressure is applied to the bonding material 305 by applying pressure to the substrate support 500 and the support member 100).

[0106] In an embodiment, the substrate support 500 comprises sintered silicon carbide.

[0107] In an embodiment, the support member 100 comprises sintered silicon carbide.

[0108] However, the support member 100 and the substrate support 500 may comprise another material, such as elemental silicon or silicon carbide. Furthermore, the support member 100 and the substrate support 500 may comprise different materials and are not necessarily formed from the same material.

[0109] In an embodiment, a shape of the recess 600 is such that the facing surface of the recess 600 conforms to a shape of the facing surface of the support member 100. An example of this is shown schematically in Figure 10A, which shows a support member 100 and a substrate support 500 having a recess 600 with bonding material 305 disposed therein prior to bonding.

[0110] For example, as shown on Figure 10A, the shape of a recess 600 may conform to the shape of the facing surface of the support member 100. According to this embodiment, a close fit between the recess 600 and the shape of the facing surface of the support member 100 may be achieved which may lead to a stronger bond between the support member 100 and substrate support 500. Figure 10B shows an example of a support member 100 which has been bonded to the substrate support 500.

[0111] Alternatively, the shape of the recess 600 may not confirm to the shape of the facing surface of the support member 100. This embodiment may be more convenient for the user performing the method if the shape of the recess 600 happens to not correspond to the shape of the facing surface of the support member 100 available. The bonding material 305 disposed between the support member 100 and the recess 600 may counteract the variations in shape where the support member 100 and the recess 600 do not conform, because the bonding material 305 is malleable prior to bonding.

[0112] In an embodiment, the substrate support 500 is configured to support a substrate W in a substrate plane and a cross-section of the recess 600 in a plane perpendicular to the substrate plane is substantially a rectangle or a trapezoid, optionally such that the facing surface of the recess 600 defines a chamfered surface. An example of this embodiment is shown in Figures 10A and 10B.

[0113] In an embodiment, the support member 100 defines a protrusion configured to protrude above a planar surface surrounding the protrusion and further configured to support a substrate W, the protrusion protruding from the surface by a distance in the range of 100 pm to 250 pm. In Figure 11, the protrusion protrudes from a planar surface surrounding the protrusion by a distance di.

[0114] In Figure 11, the longitudinal size of the protrusion is labelled di. In Figure 11, the longitudinal size of the support member 100 is labelled d.

[0115] Optionally, the longitudinal size di of the protrusion is equal to or greater than 150 pm and is equal to or less than 200 pm. Thus, protrusion formed by support member 100 protrudes from thesurface by a distance in the range of equal to or greater than 150 |im and is equal to or less than 200 |im.

[0116] Optionally, in an embodiment, the depth of the recess 600 perpendicular to the substrate plane is equal to or greater than 150 pm and is equal to or less than 250 pm. In Figure 11 the depth of the recess 600 corresponds to d - di + the thickness of the bonding material 350. However, the depth of the recess 600 is not particularly limited. A deeper recess 600 may enable a stronger bond to be formed between the support member 100 and the recess 600, as a deeper recess 600 has a larger surface area available for bonding with support member 100. However, a deeper recess 600 is more cumbersome to form in the surface of substrate support 500. Therefore, the depth of the recess 600 may be a compromise between ease of formation and the strength of the bond.

[0117] In an embodiment, at least a portion of the facing surface of the recess 600 has a local peak- to-valley distance of less than 3pm. The peak-to-valley distance is the distance between the peak (maximal value) and valley (minimal height value) on the facing surface of the recess 600 surface, representing the flatness of the surface. The peak-to-valley distance may be measured by interferometry.

[0118] By providing a portion of the facing surface of the recess 600 with a local peak-to-valley distance flatness of less than 3pm, greater adhesive strength may be achieved.

[0119] An example of a cross-section of a structure formed by this method is shown on Figure 9.The resulting microstructure reveals that the support member 100 and substrate support 500 are joined by a bonding layer 302 disposed therebetween. Oxidation layers 200 are not visible in the micrograph as they are too thin to be seen by an optical microscope; however their presence may be confirmed by a higher resolution technique such as transmission electron microscopy (TEM).

[0120] The method according to the present disclosure described above may be used to repair a substrate support 500. For example, the method may be used to repair a substrate support 500 having a broken protrusion by joining a new support member 100 by the method described above.

[0121] According to the disclosure, there is provided a method of repairing a substrate support 500, the method comprising: forming a recess 600 at a target location, and joining a support member 100 to the substrate support 500 at the target location using the method described above.

[0122] It may be advantageous to form a recess 600 at a target location prior to performing the joining method described above. The target location may be the location of a protrusion which needs to be repaired. For example, if a protrusion is damaged and needs to be removed, the protrusion may be removed and a recess may be formed at the location of the damaged protrusion. Forming a recess 600 may be advantageous, because it provides a greater surface area for a bond to be formed between a support member 100 and a substrate support 500.

[0123] Alternatively, the joining method described above may be performed by joining a support member 100 to a substrate support 500 at a target location without forming a recess 600.

[0124] In an embodiment, prior to forming the recess 600, damaged support member 100 is removed from the target location.

[0125] In an embodiment, while forming the recess 600, the remaining damaged portion of the substrate support 500 is removed at the target location. This may be advantageous as regions of the substrate support 500 adjacent to the damaged protrusion may also become damaged, and removing them will improve the strength of the substrate support 500.

[0126] The depth of the recess 600 may be larger than the depth of the damaged location in the substrate support 500. Accordingly, the likelihood of damaged locations remaining in the substrate support 500 is reduced. In an example, the depth of the recess 600 is in the range of 50 pm to 3100 pm.

[0127] According to the present disclosure, there is provided a substrate support 500 comprising a plurality of support members 100 protruding from a surface thereof, wherein the substrate support 500 is produced by repairing a substrate support 500 using any of the methods according to the present disclosure. A schematic of a cross section of such a substrate support 500 is shown on Figure 11.

[0128] According to the present disclosure, there is provided a substrate support 500 comprising silicon or a compound of silicon, the substrate support 500 comprising: at least one support member 100 protruding from a surface thereof, the support member 100 comprising silicon or a compound of silicon; and a connecting body disposed between the substrate support 500 and the support member 100, the connecting body comprising the following layers in sequence: a first layer comprising silicon oxide 200; a second layer comprising silver 302; and a third layer comprising silicon oxide 200. The connecting body may be a bond which is formed between a substrate support 500 and a support member 100 by any of the methods according to the present disclosure. When a substrate support 500 having a broken burl is repaired by joining a support member 100 via a method according to the present disclosure, the connecting body is formed between the substrate support 500 and the support member 100.

[0129] Either or both of the substrate support 500 and the support member 100 may comprise sintered silicon carbide.

[0130] In an embodiment, the support member 100 and the substrate support 500 are formed of SiSiC, and the oxide layer 200 comprises silicon oxide.

[0131] Where the term “comprising”, “comprise” or “comprises” is used, said term may substituted by “consisting of’ , “consist of’ or “consists of’ respectively, or by “consisting essentially of’ , “consist essentially of’ or “consists essentially of’ respectively. Any reference to a numerical range or single numerical value also includes values that are about that range or single value.

[0132] It will also be appreciated that the principles of the present invention can be applied to metrology or lithographic tools and clamping systems that employ electrostatic clamps. In such a case, rather than controlling the flow rate of an evacuation flow, other relevant parameters such as the voltage applied to the electrostatic clamp may be controlled.

[0133] Although specific reference may be made in this text to the use of a metrology system in the context of the manufacture of ICs, it should be understood that the metrology system described herein may have other applications, such as in 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 may be considered as synonymous with the more general terms “substrate” or “target portion", respectively. The substrate referred to herein may be processed, before or after exposure, in for example a track (a tool that typically applies a layer of resist to a substrate and develops the exposed resist), a metrology tool and / or an inspection tool. Where applicable, the disclosure herein may be applied to such and other substrate processing tools. Further, the substrate may be processed more than once, for example in order to create a multi-layer IC, so that the term substrate used herein may also refer to a substrate that already contains one or multiple processed layers.

[0134] Although specific reference may have been made above to the use of embodiments of the invention in the context of optical lithography, it will be appreciated that the invention may be used in other applications.

[0135] While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described.

[0136] The descriptions above are intended to be illustrative, not limiting. Thus, it will be apparent to one skilled in the art that modifications may be made to the invention as described without departing from the scope of the clauses set out below.1. A method of joining a support member to a substrate support, the method comprising: inserting the support member into a recess in the substrate support with a bonding material between facing surfaces of the support member and the substrate support; and applying a bonding temperature and a bonding pressure to the bonding material, wherein: the bonding material comprises a first material and a second material, wherein the first material comprises a powder of an oxalate, and the second material comprises nanoparticles.2. The method of clause 1, wherein the oxalate comprises an oxalate of a first element and the nanoparticles comprise nanoparticles of a second element.3. The method of clause 2, wherein the first element and the second element are the same.4. The method of clause 1 or 2, wherein the first element is silver, and the second element is silver.5. The method of any of clauses 1 to 4, wherein the bonding temperature is greater than a thermal decomposition temperature of the first material.6. The method of any of clauses 1 to 5, wherein the bonding temperature is a temperature at which the second material of the bonding material is caused to melt.7. The method of any of clauses 1 to 6, wherein the bonding temperature is equal to or greater than the melting point of the second material.8. The method of any of clauses 1 to 7, wherein the nanoparticles comprise nanoparticles of a diameter equal to or less than 100 nm.9. The method of any of clauses 1 to 8, wherein the bonding temperature is equal to or lower than 450°C.10. The method of any of clauses 1 to 9, further comprising, prior to the inserting the support member, applying the bonding material to either or both of the facing surfaces of the support member and the substrate support, wherein the applied bonding material comprises a solvent.11. The method of clause 10, wherein the solvent comprises acetone.12. The method of clause 10 or 11, wherein the inserting the support member into the recess is performed after the solvent has evaporated.13. The method of any of clauses 10 to 12, comprising after the applying the bonding material and prior to the inserting the support member into the recess applying an evaporating temperature to the solvent to cause the solvent to evaporate.14. The method of clause 13, wherein the evaporating temperature is below 140°C, and preferably, below 100°C.15. The method of any preceding clause, wherein the bonding pressure is in the region of equal to or greater than 1 MPa and equal or lower than the compressive strength of the substrate support and equal or lower than the compressive strength of the support member.16. The method of clause 15, wherein the bonding pressure is in the region of equal to or greater than 1 MPa and equal or lower than the compressive strength of bulk substrate material.17. The method of any preceding clause, wherein the substrate support comprises sintered silicon carbide.18. The method of any preceding clause, wherein the support member comprises sintered silicon carbide.19. The method of any preceding clause, wherein a shape of the recess is such that the facing surface of the recess conforms to a shape of the facing surface of the support member.20. The method of any preceding clause, wherein the substrate support is configured to support a substrate in a substrate plane and a cross-section of the recess in a plane perpendicular to the substrate plane is a rectangle or a trapezoid, optionally such that the facing surface of the recess defines a chamfered surface.21. The method of any preceding clause, wherein the support member defines a protrusion configured to protrude above a planar surface surrounding the protrusion and further configured to support a substrate, the protrusion protruding from the surface by a distance in the range of equal to or greater than 100 pm and equal to or less than 250 pm.22. The method of clause 21, wherein the protrusion protrudes from the surface by a distance in the range of equal to or greater than 150 pm and is equal to or less than 200 pm.23. The method of any of clauses 20 to 22, wherein a depth of the recess perpendicular to the substrate plane is equal to or greater than 50 pm and is equal to or less than 3100 pm.24. The method of any of clauses 20 to 23, wherein at least a portion of the facing surface of the recess has a local peak-to-valley distance of less than 3pm.25. A method of repairing a substrate support, the method comprising: forming a recess at a target location, and joining a support member to the substrate support at the target location using the method of any preceding clause.26. The method of clause 25, wherein the method comprises, prior to forming the recess, removing a damaged support member at the target location.27. The method of clause 25 or 26, wherein the forming the recess further comprises removing a damaged portion of the substrate at the target location.28. The method of clause 27, wherein the depth of the recess is larger than the depth of the damaged portion of the substrate.29. The method of any of clauses 25 to 28, wherein the depth of the recess is in the range of 50 pm to 3100 pm.30. A substrate support comprising a plurality of support members protruding from a surface thereof, wherein the substrate support is produced by repairing a substrate support using the method of any of clauses 25 to 29.31. A substrate support comprising silicon or a compound of silicon, the substrate support comprising: at least one support member protruding from a surface thereof, the support member comprising silicon or a compound of silicon; and a connecting body disposed between the substrate support and the support member, the connecting body comprising the following layers in sequence: a first layer comprising silicon oxalate; a second layer comprising silver; and a third layer comprising silicon oxalate.32. The substrate support of clause 31, wherein either or both of the substrate support and the support member comprise sintered silicon carbide.

Claims

CLAIMS1. A method of joining a support member to a substrate support, the method comprising: inserting the support member into a recess in the substrate support with a bonding material between facing surfaces of the support member and the substrate support; and applying a bonding temperature and a bonding pressure to the bonding material, wherein: the bonding material comprises a first material and a second material, wherein the first material comprises a powder of an oxalate, and the second material comprises nanoparticles.

2. The method of claim 1, wherein the oxalate comprises an oxalate of a first element and the nanoparticles comprise nanoparticles of a second element, desirably wherein the first element and the second element are the same, and / or wherein the first element is silver, and the second element is silver.

3. The method of claim 1 or 2, wherein the bonding temperature is greater than a thermal decomposition temperature of the first material, and / or wherein the bonding temperature is a temperature at which the second material of the bonding material is caused to melt, and / or wherein the bonding temperature is equal to or greater than the melting point of the second material, and / or wherein the bonding temperature is equal to or lower than 450°C, and / or wherein the nanoparticles comprise nanoparticles of a diameter equal to or less than 100 nm.

4. The method of any of claims 1-3, further comprising, prior to the inserting the support member, applying the bonding material to either or both of the facing surfaces of the support member and the substrate support, wherein the applied bonding material comprises a solvent, desirably wherein the solvent comprises acetone, desirably wherein the inserting the support member into the recess is performed after the solvent has evaporated, desirably comprising after the applying the bonding material and prior to the inserting the support member into the recess applying an evaporating temperature to the solvent to cause the solvent to evaporate, desirably wherein the evaporating temperature is below 140°C, and preferably, below 100°C.

5. The method of any of the preceding claims, wherein the bonding pressure is in the region of equal to or greater than 1 MPa and equal or lower than the compressive strength of the substrate support and equal or lower than the compressive strength of the support member, desirably wherein the bonding pressure is in the region of equal to or greater than 1 Mpa and equal or lower than the compressive strength of bulk substrate material.

6. The method of any of the preceding claims, wherein the substrate support comprises sintered silicon carbide, and / or wherein the support member comprises sintered silicon carbide, desirably wherein a shape of the recess is such that the facing surface of the recess conforms to a shape of the facing surface of the support member, desirably wherein the substrate support is configured to support a substrate in a substrate plane and a cross-section of the recess in a plane perpendicular to the substrate plane is a rectangle or a trapezoid, optionally such that the facing surface of the recess defines a chamfered surface.

7. The method of any of the preceding claims, wherein the support member defines a protrusion configured to protrude above a planar surface surrounding the protrusion and further configured to support a substrate, the protrusion protruding from the surface by a distance in the range of equal to or greater than 100 pm and equal to or less than 250 pm, desirably wherein the protrusion protrudes from the surface by a distance in the range of equal to or greater than 150 pm and is equal to or less than 200 pm.

8. The method of claim 6 or 7, wherein a depth of the recess perpendicular to the substrate plane is equal to or greater than 50 pm and is equal to or less than 3100 pm, and / or wherein at least a portion of the facing surface of the recess has a local peak-to-valley distance of less than 3pm.

9. A method of repairing a substrate support, the method comprising: forming a recess at a target location, and joining a support member to the substrate support at the target location using the method of any of the preceding claims.

10. The method of claim 9, wherein the method comprises, prior to forming the recess, removing a damaged support member at the target location, and / or wherein the forming the recess further comprises removing a damaged portion of the substrate at the target location, desirably wherein the depth of the recess is larger than the depth of the damaged portion of the substrate, and / or wherein the depth of the recess is in the range of 50 pm to 3100 pm.

11. A substrate support comprising a plurality of support members protruding from a surface thereof, wherein the substrate support is produced by repairing a substrate support using the method of claim 9 or 10.

12. A substrate support comprising silicon or a compound of silicon, the substrate support comprising:at least one support member protruding from a surface thereof, the support member comprising silicon or a compound of silicon; and a connecting body disposed between the substrate support and the support member, the connecting body comprising the following layers in sequence: a first layer comprising silicon oxalate; a second layer comprising silver; and a third layer comprising silicon oxalate.

13. The substrate support of claim 12, wherein either or both of the substrate support and the support member comprise sintered silicon carbide.

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