Method of manufacturing electrode for object holder

Abstract

A method of manufacturing an electrode for an object holder, the method comprising forming at least two electrode portions on a first insulating layer, the at least two electrode portions being spaced apart from each other, forming at least one insulating portion on the first insulating layer between the at least two electrode portions, the at least two electrode portions are disposed such that the at least one insulating portion fills a space between the at least two electrode portions and the at least two electrode portions and the at least one insulating portion form a planar surface, and bonding a second insulating layer to the planar surface.

Description

Cross Reference to Related Applications

[0001] This application claims priority from EP application 23180448.5, filed on 20 June 2023, and incorporated herein in its entirety by reference. TECHNICAL FIELD

[0002] The present invention relates to an electrode for an object holder, an object holder and a method of manufacturing the electrode. The object holder can be part of a stage of a lithographic apparatus or a lithographic tool. BACKGROUND

[0003] A lithographic apparatus is a machine constructed to apply a desired pattern onto a substrate. The lithographic apparatus can be used, for example, to manufacture integrated circuits (ICs). For example, the lithographic apparatus can project a pattern from a patterning device (for example a mask) onto a layer of radiation-sensitive material (resist) provided on a substrate.

[0004] To project the pattern, the lithographic apparatus can use electromagnetic radiation. The wavelength of this radiation determines the minimum size of features which can be formed on the substrate. A lithographic apparatus which uses extreme ultraviolet (EUV) radiation, having a wavelength within a range of 4-20 nm, for example 6.7 nm or 13.5 nm, can be used to form smaller features on a substrate than a lithographic apparatus which uses, for example, radiation with a wavelength of 193 nm.

[0005] A substrate to be exposed can be supported by a substrate holder (i.e. an object which directly supports the substrate), which in turn is supported by a substrate table. As the substrate can experience high accelerations when using high-throughput lithographic apparatuses, it can not be enough to allow the substrate to simply rest on the substrate holder. It is clamped in place. Two methods can be used to clamp the substrate in place - vacuum clamping and electrostatic clamping. In vacuum clamping, the space between the substrate holder and the substrate and optionally the space between the substrate table and the substrate holder is partially evacuated, such that the substrate is held in place by the higher gas or liquid pressure above it. However, vacuum clamping can not be used in cases where the environment near the beam path and / or the substrate or substrate holder is kept at low or very low pressure, for example for extreme ultraviolet (EUV) radiation lithography. In such cases, it can not be possible to generate a large enough pressure difference on the substrate (or substrate holder) to clamp it. Therefore, electrostatic clamping can be used. In electrostatic clamping, a potential difference is established between the substrate and the substrate table and / or the substrate holder. The potential difference can generate a clamping force. The substrate holder can comprise an electrode configured to generate the potential difference.

[0006] There is a need for an improved electrode which can be used in a substrate holder. SUMMARY

[0007] According to a first aspect of the present invention, there is provided a method of manufacturing an electrode for an object holder, the method comprising forming at least two electrode portions on a first insulating layer, the at least two electrode portions being spaced apart from each other, forming at least one insulating portion on the first insulating layer between the at least two electrode portions such that the at least one insulating portion fills a space between the at least two electrode portions, and the at least two electrode portions form a planar surface with the at least one insulating portion, and bonding a second insulating layer to the planar surface.

[0008] The method can allow for manufacturing of improved electrodes of an object holder. For example, by forming at least one insulating portion on the first insulating layer between the at least two electrode portions such that the at least one insulating portion fills a space between the at least two electrode portions, and the at least two electrode portions form a planar surface with the insulating portion, a distance between the at least two electrode portions can be reduced, for example while the at least one insulating portion provides electrical insulation between the at least two electrode portions. The reduced distance between the at least two electrode portions can allow for an increased number of electrode portions on the first insulating layer. This in turn can result in an increased yield of electrodes. Forming at least one insulating portion between the at least two electrode portions such that the at least one insulating portion fills a space between the at least two electrode portions can result in an increased breakdown voltage of the electrode. Forming at least one insulating portion on the first insulating layer between the at least two electrode portions such that the at least two electrode portions and the at least two electrode portions form a planar surface can allow for improved bonding of the second insulating layer with the at least two electrode portions and the at least one insulating portion.

[0009] The at least two electrode portions and the at least one insulating portion can have the same height, for example substantially the same height. This can allow for improved bonding of the second insulating layer with the at least two electrode portions and the at least one insulating portion.

[0010] The at least two electrode portions and the at least one insulating portion can be formed on: at least one side of the first insulating layer, or each of at least two opposite sides of the first insulating layer. For example, when the at least two electrode portions and the at least one insulating portion are formed on each of at least two opposite sides of the first insulating layer, the method can comprise bonding the second insulating layer to the planar surface formed on each of the at least two opposite sides of the first insulating layer.

[0011] The method can comprise forming at least two electrode portions on each of the plurality of first insulating layers. The method can comprise forming at least one insulating portion on each of the plurality of first insulating layers, for example between the at least two electrode portions, such that the at least one insulating portion fills a space between the at least two electrode portions and the at least two electrode portions form a planar surface with the at least one insulating portion. The method can comprise bonding the plurality of first insulating layers and / or the second insulating layer together, for example such that the at least two electrode portions and the at least insulating portion on each of the plurality of first insulating layers are arranged: between the second insulating layer and a respective one of the plurality of first insulating layers, or between a respective one of the plurality of first insulating layers and at least one other of the plurality of first insulating layers.

[0012] The at least two electrode portions and the at least one insulating portion can be formed on at least one side of each of the plurality of first insulating layers and / or each of at least two opposing sides of at least one of the plurality of first insulating layers.

[0013] The method can comprise bonding the second insulating layer to the planar surface and / or bonding the plurality of first insulating layers and / or the second insulating layer together, for example using at least one of: a diffusion bonding process, an anodic bonding process, a discharge plasma assisted thermal compression process, and / or an optical contact bonding process.

[0014] Forming the at least one insulating portion on the first insulating layer and / or each of the plurality of first insulating layers can comprise depositing a layer of insulating material on the at least two electrode portions and the first insulating layer and / or each of the plurality of first insulating layers. Forming the at least one insulating portion on the first insulating layer and / or each of the plurality of first insulating layers can comprise removing a portion of the layer of insulating material, for example such that the at least two electrode portions form a planar surface with at least one remaining portion of the layer of insulating material. The at least one remaining portion can form or comprise the at least one insulating portion.

[0015] The first insulating layer, the second insulating layer, and / or the at least one or each of the first insulating layers of the plurality of first insulating layers can comprise a ceramic material or a glass material. The ceramic material or the glass material of the first insulating layer, the at least one or each of the first insulating layers of the plurality of first insulating layers, and / or the at least one of the second insulating layer can be the same or different from the ceramic material or the glass material of the other of the first insulating layer, the at least one or each of the first insulating layers of the plurality of first insulating layers, and / or the at least one of the second insulating layer. By providing the first insulating layer, the at least one or each of the first insulating layers of the plurality of first insulating layers, and / or the at least one of the second insulating layer comprising a ceramic material, the robustness and / or the fracture toughness of the electrode can be improved. The ceramic material can comprise a light- impermeable or non-transparent ceramic material.

[0016] The at least two electrode portions can comprise an electrically conductive material. The at least one insulating portion can comprise an insulating material. The insulating material can have a hardness that is less than a hardness of the electrically conductive material. The use of an insulating material having a hardness that is less than a hardness of the electrically conductive material can allow the insulating portion to be formed at the same height as the at least two electrode portions, e.g. using a polishing or planarization process. Additionally or alternatively, this can facilitate the formation of a planar surface.

[0017] The electrically conductive material comprises at least one of: an electrically conductive ceramic material, a semiconductor material, and / or doped diamond. The insulating material comprises at least one of: a quartz material, a glass material, and / or a ceramic material.

[0018] The first insulating layer, the at least one of the plurality of first insulating layers, and / or the second insulating layer can comprise one or more electrically conductive portions. The one or more electrically conductive portions can be configured and / or arranged to electrically connect one or more respective electrode portions of the at least two electrode portions, e.g. arranged or formed on each of the at least two opposite sides of the first insulating layer and / or the at least one of the plurality of first insulating layers. The one or more electrically conductive portions can be configured and / or arranged to electrically connect one or more electrode portions of the at least two electrode portions formed on the first insulating layer and / or the at least one of the plurality of first insulating layers together with another portion or component of the object holder.

[0019] According to a second aspect of the present invention, there is provided an electrode for an object holder, comprising: at least two electrode portions arranged or formed on a first insulating layer, the at least two electrode portions being spaced apart from each other; and at least one insulating portion arranged or formed on the first insulating layer between the at least two electrode portions, such that the at least one insulating portion fills a space between the at least two electrode portions, and the at least two electrode portions form a planar surface with the at least one insulating portion; and a second insulating layer bonded to the planar surface.

[0020] The at least two electrode portions and the at least one insulating portion can be arranged or formed on at least one side of the first insulating layer or each of at least two opposite sides of the first insulating layer. For example, when the at least two electrode portions and the at least one insulating portion are arranged or formed on each of at least two opposite sides of the first insulating layer, the second insulating layer can be bonded to the planar surfaces formed on each of the at least two opposite sides of the first insulating layer.

[0021] The electrode can comprise a plurality of first insulating layers. The at least two electrode portions can be formed or arranged on each of the plurality of first insulating layers. The electrode can comprise at least one insulating portion arranged or formed on each of the plurality of first insulating layers between the at least two electrode portions, for example such that the at least one insulating portion fills a space between the at least two electrode portions and the at least two electrode portions form a planar surface with the at least one insulating portion. The plurality of first insulating layers and / or the second insulating layer can be bonded together, for example such that the at least two electrode portions and the at least one insulating portion on each of the plurality of first insulating layers are arranged between the second layer and a respective one of the plurality of first insulating layers. The plurality of first insulating layers and / or the second insulating layer can be bonded together, for example such that the at least two electrode portions and the at least one insulating portion on each of the plurality of first insulating layers are arranged between a respective one of the plurality of first insulating layers and at least one other of the plurality of first insulating layers.

[0022] The electrode can comprise one or more electrically conductive portions, such as one or more vias. The one or more electrically conductive portions can be part of or comprised in the first insulating layer, at least one of the plurality of first insulating layers, and / or the second insulating layer. The one or more electrically conductive portions can be configured and / or arranged to electrically connect one or more respective electrode portions of the at least two electrode portions arranged or formed on each of the at least two opposite sides of the first insulating layer and / or at least one of the plurality of first insulating layers. The one or more electrically conductive portions can be configured and / or arranged to electrically connect one or more electrode portions of the at least two electrode portions formed on the first insulating layer and / or at least one of the plurality of first insulating layers with another portion or component of the object holder.

[0023] The electrode can be manufactured using the method of the first aspect.

[0024] According to a third aspect of the present application, there is provided an object holder configured to support an object comprising an electrode according to the second aspect.

[0025] According to a fourth aspect of the present application, there is provided a stage comprising an object holder according to the third aspect.

[0026] According to a fifth aspect of the application, there is provided a lithographic apparatus comprising an illumination system, a projection system, and an object table according to the fourth aspect.

[0027] According to a sixth aspect of the application, there is provided a lithographic tool comprising an object table according to the fourth aspect.

[0028] The various aspects and features of the application set out above or below can be combined with the various other aspects and features of the application, as will be apparent to the skilled person. BRIEF DESCRIPTION OF DRAWINGS

[0029] Embodiments of the application will now be described, by way of example only, with reference to the accompanying schematic drawings in which:

[0030] Figure 1 A lithographic system comprising a lithographic apparatus and a radiation source is depicted;

[0031] Figure 2 A portion of an exemplary electrode for an object holder in a lithographic apparatus of Figure 1 is schematically depicted in cross-section;

[0032] Figure 3 A plan view of an electrode of Figure 2 is depicted;

[0033] Figure 4 A portion of another exemplary electrode for an object holder in a lithographic apparatus of Figure 1 is schematically depicted in cross-section;

[0034] Figure 5 A portion of an exemplary object holder for a lithographic apparatus of Figure 1 is schematically depicted in cross-section;

[0035] Figure 6 A flowchart is depicted to outline a method of manufacturing an electrode for an object holder; and

[0036] Figure 7 A flowchart is depicted to outline one or more steps that can be part of a method of Figure 6 . DETAILED DESCRIPTION

[0037] Figure 1A lithographic system is shown that includes a radiation source SO and a lithographic apparatus LA. The radiation source SO is configured to generate an EUV radiation beam B and to supply the EUV radiation beam B to the lithographic apparatus LA. The lithographic apparatus LA includes an illumination system IL, a support structure MT configured to support a patterning device MA, e.g., a mask, a projection system PS, and a wafer stage WT. The wafer stage WT can include an object holder WH configured to support an object W. The object W can be provided in the form of a substrate. The wafer stage WT can be provided in the form of a substrate table. The object holder WH can be provided in the form of a substrate clamp.

[0038] The illumination system IL is configured to condition the EUV radiation beam B before it is incident upon the patterning device MA. Thereamong, the illumination system IL can include a facetted field mirror device 10 and a facetted pupil mirror device 11. The facetted field mirror device 10 and the facetted pupil mirror device 11 together provide for the EUV radiation beam B having a desired cross-sectional shape and a desired intensity distribution. In addition to or instead of the facetted field mirror device 10 and the facetted pupil mirror device 11, the illumination system IL can include other mirrors or devices.

[0039] After being so conditioned, the EUV radiation beam B interacts with the patterning device MA. As a result of this interaction, a patterned EUV radiation beam B’ is generated. The projection system PS is configured to project the patterned EUV radiation beam B’ onto the substrate W. For this purpose, the projection system PS can include a plurality of mirrors 13, 14, which are configured to project the patterned EUV radiation beam B’ onto a substrate W held by the wafer stage WT. The projection system PS can apply a reduction factor to the patterned EUV radiation beam B’, thereby forming an image with features that are smaller than corresponding features on the patterning device MA. For example, a reduction factor of 4 or 8 can be applied. Although the projection system PS is illustrated as having only two mirrors 13, 14, the projection system PS can include a different number of mirrors (e.g., six or eight mirrors). Figure 1

[0040] The substrate W can include a previously formed pattern. In this case, the lithographic apparatus LA aligns an image formed by the patterned EUV radiation beam B’ with the pattern previously formed on the substrate W.

[0041] A relative vacuum (i.e., a small amount of gas (e.g., hydrogen) at a pressure much lower than atmospheric pressure) can be provided in the radiation source SO, the illumination system IL, and / or the projection system PS.

[0042] Figure 1 ​The illustrated radiation source SO is of a type that can be referred to as a laser produced plasma (LPP) source. A laser system 1 (which may, for example, comprise a CO2laser) is arranged to deposit energy into a fuel, such as tin (Sn) provided from, for example, a fuel emitter 3, via a laser beam 2. Although reference is made to tin in the following description, any suitable fuel can be used. The fuel may, for example, be in liquid form and may, for example, be a metal or an alloy. The fuel emitter 3 can comprise a nozzle configured to direct tin, for example in the form of droplets, along a trajectory towards a plasma formation region 4. The laser beam 2 is incident on the tin at the plasma formation region 4. Deposition of laser energy into the tin creates a tin plasma 7 at the plasma formation region 4. Radiation, including EUV radiation, is emitted from the plasma 7 during de-excitation and recombination of the electrons with the ions of the plasma.

[0043] EUV radiation from the plasma is collected and focused by a collector 5. The collector 5 comprises, for example, a near-normal incidence radiation collector 5 (sometimes more generally referred to as a normal incidence radiation collector). The collector 5 can have a multilayer mirror structure arranged to reflect EUV radiation (for example EUV radiation having a desired wavelength such as 13.5 nm). The collector 5 can have an elliptical configuration, with two foci of the ellipse. As discussed below, a first of the foci can be at the plasma formation region 4 and a second of the foci can be at an intermediate focus 6.

[0044] The laser system 1 can be spatially separated from the radiation source SO. In this case, the laser beam 2 can be passed from the laser system 1 to the radiation source SO by means of a beam delivery system (not shown) comprising, for example, suitable directing mirrors and / or a beam expander and / or other optics. The laser system 1, the radiation source SO and the beam delivery system can together be considered to be a radiation system.

[0045] Radiation reflected by the collector 5 forms an EUV radiation beam B. The EUV radiation beam B is focused at the intermediate focus 6 to form an image at the intermediate focus 6 of the plasma present at the plasma formation region 4. The image at the intermediate focus 6 acts as a virtual radiation source for an illumination system IL. The radiation source SO is arranged such that the intermediate focus 6 is located at or near an opening 8 in an enclosing structure 9 of the radiation source SO.

[0046] Although Figure 1 The radiation source SO is depicted as a laser produced plasma (LPP) source, any suitable source such as a discharge produced plasma (DPP) source or a free electron laser (FEL) can be used to generate EUV radiation.

[0047] Figure 2 A schematic cross-section is shown of a lithographic apparatus LA for Figure 1A portion of an exemplary electrode 16 of an object holder WH of the lithographic apparatus LA is shown. In Figure 2 In the embodiment shown, the electrode 16 can be configured to function as an object holder WH. The electrode 16 comprises two electrode portions 16a arranged on a first insulating layer 18. The electrode 16 can also be referred to as a structured electrode. In this embodiment, the object holder WH is provided in the form of an electrostatic clamp, such as a bipolar electrostatic clamp. Although Figure 2 Two electrode portions 16a are shown, but it will be appreciated that in other embodiments, the electrode can comprise more than two electrode portions. For example, in other embodiments, the electrode can comprise tens, hundreds or thousands of electrode portions.

[0048] The electrode 16 comprises an insulating portion 20. The insulating portion 20 is arranged or formed between the electrode portions 16a. The insulating portion 20 is arranged or formed to fill the space between the electrode portions 16a. The insulating portion 20 can be arranged between the electrode portions 16a to electrically isolate the electrode portions 16a from each other. This can allow independent and / or individual control of the voltage applied to the electrode 16 (e.g. the two electrode portions 16a). For example, a plurality of voltages can be applied to the electrode portions 16a which are opposite. In use, when a voltage is applied to the electrode 16 (e.g. the electrode portions 16a), a potential difference is generated between the object holder WH and the object W. This will result in an electrostatic clamping effect, thereby clamping the object W to the object holder WH, e.g. the wafer table WT. The voltage applied to the electrode 16 (e.g. the electrode portions 16a) can be in the range of about 1 kV to 8 kV, for example in order to generate a sufficient clamping force. By forming or arranging the insulating portion 20 between the electrode portions 16a such that the insulating portion 20 fills the space between the electrode portions 16a, the distance between the electrode portions 16a can be reduced, whilst the insulating portion 20 provides electrical isolation between the electrode portions 16a, as described in more detail below. The reduced distance between the electrode portions 16a can allow an increase in the number of electrode portions on the first insulating layer 18. This in turn can result in an increase in the yield of the electrode 16. Additionally or alternatively, the arrangement or formation of the insulating portion 20 between the electrode portions 16a, e.g. such that the insulating portion fills the space between adjacent electrode portions, can result in an increase in the breakdown voltage of the electrode 16. The insulating portion 20 and the electrode portions 16a can form an electrode layer 24.

[0049] The insulating portion 20 is arranged or formed between the electrode portions 16a, e.g. such that the electrode portions 16a form a planar surface 22 with the electrode portions 16a. For example, the electrode portions 16a and the insulating portion 20 can be arranged or formed to form the planar surface 22. For example, the electrode portions 16a and the insulating portion 20 can comprise the same height H. Although Figure 2A single insulating portion 20 is shown, but it should be understood that in other embodiments, the electrode may include more than one insulating portion. Additionally, the electrode 16 may include at least another insulating portion arranged to electrically isolate the electrode portion 16a from the outside of the electrode 16.

[0050] Electrode 16 includes a second insulating layer 26 bonded to a planar surface 22. In other words, the second insulating layer 26 is bonded to the electrode portion 16a and the insulating portion 20. The bonding or connection of the second insulating layer 26 to the electrode portion 16a and the insulating portion 20 can be improved by arranging or forming the electrode portion 16a and the insulating portion 20 at the same height H and / or forming the planar surface 22. Electrode 16 may be provided in the form of an embedded electrode. In this embodiment, the second insulating layer 26 may include or define an object receiving surface 26a.

[0051] Figure 3 It shows Figure 2 The diagram shows a plan view of electrode 16. For clarity, Figure 3 The second insulating layer is omitted. The object retainer WH can have a circular shape. The diameter of the object retainer WH can range from about 340 mm to 400 mm, such as 350 mm. It should be understood that the dimensions of the object retainer disclosed herein are merely exemplary dimensions, and other dimensions of the object retainer may be used in other embodiments.

[0052] exist Figure 3 In the illustrated embodiment, the diameter of the first insulating layer 18 is larger than the diameter of the electrode 16. This allows another insulating portion (not shown) to be arranged around at least a portion of the periphery of the electrode 16, for example, electrically isolating the electrode portion 16a from the outside of the electrode 16.

[0053] As described above, in this embodiment, the electrode 16 comprises two electrode portions 16a. Each of the two electrode portions 16a can be substantially semi-circular. A first voltage source 27a can be connected to one of the two electrode portions 16a. The first voltage source 27a can be configured to apply a voltage to the one of the two electrode portions 16a. A second voltage source 27b can be connected to the other of the two electrode portions 16a. The second voltage source 27b can be configured to apply a voltage to the other of the two electrode portions 16a. The first voltage source 27a and the second voltage source 27b can be configured to apply opposite voltages to the two electrode portions 16a. The two electrode portions 16a can be arranged adjacent to each other. However, as described above, the two electrode portions 16a are electrically isolated from each other by the insulating portion 20. The first voltage source 27a and / or the second voltage source 27b can be controlled by the controller CT. It will be appreciated that the arrangement and / or shape of the electrode portions disclosed herein are merely exemplary dimensions, and that in other embodiments, the shape and / or arrangement of the electrode portions can be different.

[0054] The electrodes 16 described herein are not limited to being implemented as described above with respect to Figure 2 and 3 described above, and can be implemented differently in the object holder. For example, in other embodiments, the electrodes can be part of a modular object holder. In other embodiments, the electrodes can be implemented as electrostatic sheets of a modular object holder, such as the object holders described in WO 2021 / 185552 or WO 2021 / 240074, both of which are incorporated herein in their entirety by reference.

[0055] Figure 4 A portion of another exemplary electrode 16 of an object holder for Figure 1 the lithographic apparatus LA shown in Fig. 1 is schematically shown in cross-section. Figure 4 The electrode 16 in Fig. 2 is similar to the electrode shown in Figure 2 and 3 Fig. 1. Therefore, any features described with respect to the electrode shown in Figure 2 and 3 Fig. 1 can also apply to the electrode shown in Fig. 2. Only differences will be described below. Figure 4 In Fig. 2, the electrode 16 comprises two electrode portions 16a. Each of the two electrode portions 16a can be substantially semi-circular. A first voltage source 27a can be connected to one of the two electrode portions 16a. The first voltage source 27a can be configured to apply a voltage to the one of the two electrode portions 16a. A second voltage source 27b can be connected to the other of the two electrode portions 16a. The second voltage source 27b can be configured to apply a voltage to the other of the two electrode portions 16a. The first voltage source 27a and the second voltage source 27b can be configured to apply opposite voltages to the two electrode portions 16a. The two electrode portions 16a can be arranged adjacent to each other. However, as described above, the two electrode portions 16a are electrically isolated from each other by the insulating portion 20. The first voltage source 27a and / or the second voltage source 27b can be controlled by the controller CT. It will be appreciated that the arrangement and / or shape of the electrode portions disclosed herein are merely exemplary dimensions, and that in other embodiments, the shape and / or arrangement of the electrode portions can be different.

[0056] Figure 4 ​In the illustrated embodiment, the electrode 16 comprises three electrode portions 16a and two insulating portions 20. Each insulating portion 20 is arranged between two adjacent electrode portions 16a. In this embodiment, the electrode portions 16a and the two insulating portions 20 are arranged on each of the opposite sides of the first insulating layer 18. The electrode portions 16a and the insulating portions 20 are arranged to form electrode layers 24a, 24b on each of the opposite sides of the first insulating layer 18. As mentioned above, the electrode portions 16a and the insulating portions 20 form planar surfaces on each of the opposite sides of the first insulating layer 18. In this embodiment, the second insulating layer 26 is bonded to the planar surfaces 22 on each of the opposite sides of the first insulating layer 18. However, it is to be understood that in other embodiments, a further first insulating layer can be bonded to the planar surface of at least one of the opposite sides of the first insulating layer 18.

[0057] The electrode 16 can comprise one or more electrically conductive portions. In this embodiment, the electrically conductive portions are part of the first insulating layer 18. However, it is to be understood that in other embodiments, the electrically conductive portions can be part of the second insulating layer. The electrically conductive portions can be implemented as vias 28. The vias 28 can be arranged to electrically connect one or more respective electrode portions 16a formed or arranged on each of the opposite sides of the first insulating layer 18 to each other, as Figure 4 illustrated. In such embodiments, the first insulating layer 18 can be referred to as an interposer layer. It is to be understood that in other embodiments, the vias can be arranged to electrically connect respective electrode portions formed on one first insulating layer to electrode portions formed on another first insulating layer. Alternatively or additionally, the vias can be arranged to connect one or more electrode portions to another portion or component of the object holder, such as a sensor, a heating element, other electrode portions, etc.

[0058] Figure 4 The illustrated electrode 16 can be seen as defining a stacked arrangement of electrode portions 16a and insulating portions 20. In this embodiment, the electrode 16 comprises two electrode layers 24a, 24b. The electrode layers 24a, 24b are arranged or stacked on top of each other. Although in the illustrated embodiment, the electrode comprises two electrode layers 24a, 24b, it is to be understood that in other embodiments, the electrode can comprise more or less than two electrode layers. Figure 4

[0059] By configuring the electrode 16 to comprise a stacked arrangement of electrode portions 16a and insulating portions 20, the electrode 16 can be used for an active or adaptive object holder. For example, a voltage can be applied to two or more electrode portions 16a of the first electrode layer 24a. The first electrode layer 24 can be arranged below the first insulating layer 18 and / or distal to the object receiving surface (not shown) of the object holder. For the sake of clarity, Figure 4 the second electrode layer 24b can be arranged to apply a voltage to the two or more electrode portions 16a of the second electrode layer 24b. The second electrode layer 24b can be arranged on the object receiving surface of the object holder.​Figure 4 A voltage is shown applied to two of the electrode portions 16a. However, it will be appreciated that a voltage can be applied to each of the electrode portions 16a. The electrode portions 16a of the first electrode layer 24a can be electrically connected with the electrode portions 16a of the second electrode layer 24 via the vias 28. The second electrode layer 24b can be formed above the first insulating layer 18 and / or proximal to the object receiving surface of the object holder. The electrode portions 16a of the second electrode layer 24b can be configured to generate a clamping force. The voltage applied to the first electrode layer 24a (e.g. two or more of its electrode portions 16a) can be applied to the second electrode layer 24b (e.g. two or more of its electrode portions 16a) via the vias 28. In some embodiments, different voltages can be applied to the two or more electrode portions 16a of the second electrode layer 24b, e.g. via the electrode portions 16a of the first electrode layer 24a. The different voltages can be selected to keep the object W substantially flat on the object holder WH and / or to avoid deformation of the object W and / or the object holder WH. For example, the lithographic exposure of the object W can cause heat to be generated in the object W. The generated heat can cause the object W to locally expand and / or deform.

[0060] Figure 5 A portion of an exemplary object holder WH for a lithographic apparatus LA is shown in cross-section. The object holder WH comprises electrodes 16. Figure 1 The electrodes shown are similar to the electrodes shown in Figure 5 The electrodes shown are similar to the electrodes shown in Figure 4 The electrodes shown are similar to the electrodes shown in Figure 4 Any features described in relation to the electrodes shown in Figure 5 The electrodes shown are similar to the electrodes shown in Figure 5 The object holder WH shown can be considered another exemplary adaptive or active object holder. In this embodiment, each of the first electrode layer 24a and the second electrode layer 24b comprises two electrode portions 16a and one insulating portion 20. The insulating portion 20 is arranged between the two electrode portions 16a.

[0061] In this embodiment, the object holder WH comprises a plurality of burls 30. The burls 30 can be arranged to extend or protrude from the electrodes 16 (e.g. the second insulating layer 24). However, it will be appreciated that in other embodiments, the burls can extend or protrude from another layer or portion of the object holder. Each of the burls comprises an object receiving surface 30a.

[0062] In this embodiment, the object holder WH comprises a plurality of burls 30. The burls 30 can be arranged to extend or protrude from the electrodes 16 (e.g. the second insulating layer 24). However, it will be appreciated that in other embodiments, the burls can extend or protrude from another layer or portion of the object holder. Each of the burls comprises an object receiving surface 30a. Figure 5In the illustrated embodiment, the burls extend or protrude upwardly from the electrodes 16. However, it is to be appreciated that in other embodiments, the burls can additionally or alternatively extend or protrude downwardly from another layer or portion of the electrodes and / or object holder. The burls 30 can define or be arranged as an array of burls. The burls 30 can have a cylindrical or truncated conical shape. A diameter DM of each burl 30 can be in a range of about 150 pm to 1000 pm. A height H of each burl 30 can be in a range of about 100 pm to 3000 pm. A distance D between at least two adjacent burls 30 can be in a range of about 2 mm to 3 mm. It is to be appreciated that the dimensions of the burls disclosed herein are merely exemplary dimensions, and in other embodiments, the burls can have other dimensions.

[0063] A voltage can be applied to the electrode portions 16a of the first electrode layer 24a, for example to generate a clamping force. In use, clamping of an object W to the object receiving surface 30a of each burl 30 can cause compression of one or more burls 30. Accordingly, it can be desirable to change a size or dimension of the burls 30, such as at least a height, for example to compensate for compression of the burls and / or to keep the object W substantially flat. The size or dimension of the burls 30 can be changed by, for example, heating the burls 30. For example, by heating the burls 30, the burls can expand and / or the height of the burls 30 can increase. In such embodiments, the object holder WH can include a plurality of heating elements 32. The heating elements 32 can be arranged to heat one or more burls 30. In Figure 5 In the illustrated example, the heating elements 32 can be arranged to heat three burls. However, it is to be appreciated that in other embodiments, the heating elements can be arranged to heat more or less than three burls. The burls 30 can include a semi-conductor material (such as silicon carbide or the like), a ceramic material (such as an insulating ceramic material), a glass material, or the like. The ceramic material can include alumina or the like. The glass material can include a quartz glass material, such as silica or fused quartz or the like. It is to be appreciated that the burls described herein are not limited to including the exemplary materials disclosed herein, and in other embodiments, the burls can include another material.

[0064] A voltage can be applied to the electrode portions 16a of the second electrode layer 24b. The second insulating layer 26 can include a via 28, for example to electrically connect at least one electrode portion 16a of the second electrode layer 24b to at least one heating element 32. It is to be appreciated that in other embodiments, the via can be differently arranged. The electrode portions 16a of the second electrode layer 24b can be used to control one or more burls 30 of the object holder WH. In Figure 5In the example shown, each electrode portion 16a of the second electrode layer 24b is associated with and / or arranged to control three protrusions 30. It should be understood that in other embodiments, the electrode portions may be associated with and / or arranged to control more or fewer than three protrusions.

[0065] Alternatively, the spikes may include piezoelectric materials such as nano-silicon nitride, lead zirconium titanate (PZT or Pb(Zr,Ti)O3), lead magnesium niobate, lead titanate (PMN-PT or Pb(Mg)O3), etc. 1 / 3 Nb 2 / 3 Barium titanate (BTO or BaTiO3), barium strontium titanate (BST or BaTiO3), and barium strontium titanate (BST or BaTiO3) 0.5 Sr 0.5 TiO3), sodium potassium niobate (KNN or K) 0.5 Na 0.5 NbO3), sodium potassium bismuth titanate (KNBT or (K,Na) 0.5 Bi 0.5 TiO3), bismuth ferrite (BFO or BiFeO3), etc. Then, as described above, the size or dimension of one or more protrusions can be changed by applying a voltage to one or more protrusions, for example, through the electrode portion of the second electrode layer. In this embodiment, Figure 5 The heating element shown can be replaced by electrodes or electrical contacts. The electrodes or electrical contacts can be configured to apply voltage to the protrusion, for example, via an electrode portion of a second electrode layer.

[0066] It should be understood that in other embodiments, the electrodes may be used and / or implemented differently. For example, in other embodiments, a voltage may be applied to an electrode layer or at least two electrode portions via one or more vias, for example to generate an electrostatic clamping force, and another voltage may be applied to another electrode layer or at least two other electrode portions, for example to another component of the object holder (such as a sensor).

[0067] Figure 6 A flowchart is shown to outline a method 100 illustrating the manufacture of electrodes for an object holder (such as an object holder WH). Figures 2 to 5 Any of the electrodes 16 shown can be manufactured using method 100.

[0068] In step 105, method 100 may include forming or providing a first insulating layer 18. The first insulating layer 18 may include a ceramic material or a glass material. The ceramic material of the first insulating layer 18 may include silicon nitride, alumina, aluminum nitride, etc. The glass material may include borosilicate glass, etc.

[0069] Method 100 can include providing a first material for forming the first insulating layer 18. The first material can be provided in the form of a ceramic suspension. It is to be appreciated that in other embodiments, the first material can be provided in the form of a powder, or the like. The ceramic suspension of the first material can also be referred to as a green ceramic. The first material can be soft and / or deformable to facilitate shaping of the first material, such as shaping into a selected or desired shape and / or to allow printing of the first material. Method 100 can include forming the first insulating layer using a sintering and / or hot pressing process. The sintering and / or hot pressing process can include heating the first material at a temperature of about 1500 °C to 1700 °C. It is to be appreciated that in other embodiments, the first insulating layer can be formed using a deposition process, such as chemical vapor deposition.

[0070] The thickness of the first insulating layer 18 can be between about 1 mm and 20 mm. The first insulating layer 18 can include a bulk resistance in the range of 10 16 ohm centimeters to 10 18 ohm centimeters.

[0071] In steps 110 and 115, method 100 includes forming at least two electrode portions 16a on the first insulating layer 18. For example, in step 110, the method can include depositing a layer of conductive material 34 on the first insulating layer 18, such as using a deposition process, such as a vacuum deposition process or a physical vapor deposition process. The layer of conductive material 34 can include a conductive material. The conductive material can include a hardness greater than 9 GPa Vickers hardness. For example, the hardness of the conductive material can be in the range of about 10 GPa to 20 GPa, such as about 15 GPa. The conductive material can include a conductive ceramic material, such as titanium nitride, or the like, and / or a semiconductor material, such as silicon carbide, or the like. The conductive material can include a bulk resistance less than 1 Ω·cm, preferably less than 0.1 Ω·cm or less than or equal to 1 μΩ·cm.

[0072] In examples in which the conductive material includes titanium nitride, the conductive material can include an excess of titanium relative to stoichiometric titanium nitride. For example, the conductive material can include a titanium nitride composition that is 10% more titanium than stoichiometric titanium nitride. This can facilitate bonding of the second insulating layer to the electrode portions 16a, as will be described below.

[0073] In some embodiments, the conductive material can include doped diamond, such as boron-doped diamond. An example bulk concentration of boron in the diamond can be between about 100 ppm (0.01%) and 8000 ppm (0.8%). In such embodiments, the conductive material can include a bulk resistance of about 5 x 10 -3 ohm centimeters and 200 x 10 -3 ohm centimeters, such as about 25 x 10 -3 ohm centimeters.

[0074] For example, at step 115, the method 100 can include removing one or more portions of the conductive material layer 34 to form the electrode portions 16a. The step 115 can include using a material removal process, such as removing portions of the conductive material layer 34. The material removal process can include a photolithography process, such as a photoresist process, and / or the like. For example, a photoresist layer can be deposited on the conductive material layer 34 (not shown in FIG. 1). The photoresist layer can be masked, exposed, and / or developed to form a pattern of the electrode portions 16a in the photoresist layer. The method 100 can include an etching process to remove one or more portions of the conductive layer 34 that are not protected by the photoresist layer, such as to form the pattern of the electrode portions 16a. In some embodiments, the photoresist layer can be removed after the etching process. Figure 6 Figure 6 In the illustrated embodiment, three electrode portions 16a are formed. A space or gap 35 can be formed between adjacent electrode portions 16a. It is to be appreciated that in other embodiments, more or less than three electrode portions can be formed.

[0075] It is to be appreciated that the methods disclosed herein are not limited to using a photolithography process to remove one or more portions of the conductive material layer. For example, in other embodiments, one or more other material removal processes, such as laser ablation, and / or the like, can be used.

[0076] Each electrode portion 16a can include a thickness between about 5 nm and about 100 μιη.

[0077] At steps 120 and 125, the method 100 includes forming at least one insulating portion 20 on the first insulating layer 18. The insulating portion 20 is formed between adjacent electrode portions 16a such that the electrode portions 16a and the insulating portion 20 form a planar surface 22. For example, at step 120, the method 100 includes depositing an insulating material layer 36 on the electrode portions 16a and the first insulating layer 18. The insulating material layer 36 can be deposited on the electrode portions 16a and the first insulating layer 18 using a deposition process, such as physical vapor deposition or other deposition process. The insulating material layer 36 can be deposited such that the space or gap 35 between adjacent electrode portions 16a is filled with the insulating material. The insulating material can include a hardness that is less than a hardness of the conductive material of the electrode portions 16a. For example, the insulating material can include a hardness that is equal to or less than 9 GPa Vickers hardness. The insulating material can include a quartz material, such as silicon dioxide, fused quartz, and / or the like, a glass material, such as borosilicate glass, a ceramic material, such as aluminum oxide, and / or another insulating material.

[0078] At step 125, the method 100 includes removing a portion of the insulating material layer 36. The portion of the insulating material layer 36 removed at this step is between the electrode portions 16a. In some embodiments, the portion of the insulating material layer 36 removed at this step is between the electrode portions 16a and the first insulating layer 18. Figure 6 ​A portion 36a of the insulating material layer 36 can be removed such that the electrode portions 16a form the planar surface 22 with one or more remaining portions of the insulating material layer 36. Each of the one or more remaining portions of the insulating material layer 36 can form an insulating portion 20. The insulating portions 20 fill the spaces or gaps 35 between adjacent electrode portions 16a. The portion 36a of the insulating layer 36 can be removed such that the electrode portions 16a are exposed. In other words, the insulating material of the insulating material layer 36 can not be present on the electrode portions 16a. The method 100 can include removing the portion 36a of the insulating material layer 36 using a polishing or planarization process. The use of an insulating material having a hardness less than the hardness of the conductive material of the electrode portions 16a can allow the insulating portions 20 to be formed at the same height as the electrode portions 16a. This can facilitate the formation of the planar surface 22.

[0079] In step 130, the method includes bonding a second insulating layer 26 to the planar surface 22. For example, the second insulating layer 26 is bonded to the electrode portions 16a and the insulating portions 20. In this embodiment, the second insulating layer 26 is bonded to the planar surface 22 using a diffusion bonding process. The press pressure and / or temperature can be selected based on the material of the second insulating layer 26, the insulating material of the insulating portions 20, and / or the conductive material of the electrode portions 16a. For example, the temperature during bonding of the second insulating layer 26 to the planar surface 22 can be in the range of about 240 °C to 2000 °C, preferably in the range of about 500 °C to 1500 °C, such as about 900 °C. The press pressure can be in the range of about 5 x 10 6 Pa (2000 bar), preferably in the range of about 1.5 x 10 8 Pa (2000 bar), preferably in the range of about 1.5 x 10 7 Pa (2000 bar), preferably in the range of about 1.5 x 10 7 Pa (2000 bar), preferably in the range of about 1.5 x 10

[0080] The second insulating layer 26 can include a ceramic material or a glass material. The ceramic material or the glass material of the second insulating layer 26 can be the same as the ceramic material or the glass material of the first insulating layer 18. Alternatively, the ceramic material or the glass material of the second insulating layer 26 can be different from the ceramic material or the glass material of the first insulating layer 18. In an example, in a case where the ceramic material or the glass material of the second insulating layer 26 is different from the ceramic material or the glass material of the first insulating layer 18, the ceramic material or the glass material of the second insulating layer 26 can include a coefficient of thermal expansion that is the same as or similar to a coefficient of thermal expansion of the ceramic material or the glass material of the first insulating layer 18. The ceramic material of the second insulating layer 26 can include at least one of silicon nitride, aluminum oxide, and / or aluminum nitride. The glass material of the second insulating layer 26 can include borosilicate glass or the like. The second insulating layer 26 can be formed in the same manner as the first insulating layer 18. The thickness of the second insulating layer 26 can be between about 1 mm and 20 mm. The second insulating layer 26 can include a volume resistance in a range of about 10 16 ohm centimeters to 10 18 ohm centimeters.

[0081] The method 100 can allow for improved electrodes of the manufacturing object holder WH. For example, as described above, by forming the insulating portion 20 between adjacent electrode portions 16a such that the insulating portion 20 fills the space 35 between the adjacent electrode portions 16a and the electrode portions 16a form a planar surface with the insulating portion 20, the distance between the electrode portions 16a can be reduced while providing electrical insulation between the electrode portions at the insulating portion 20. For example, the distance D between at least two adjacent electrode portions 16a can be equal to or greater than about 0.1 mm. The minimum value of the distance D between adjacent electrode portions can depend on the breakdown voltage of the insulating material of the insulating portion 20. The reduced distance D between adjacent electrode portions can allow for an increased number of electrode portions on the first insulating layer 18. This in turn can result in an increased yield of electrodes 16. Forming the insulating portion 20 between adjacent electrode portions 16a, for example such that the insulating portion 20 fills the space 35 between the adjacent electrode portions 16a, can result in an increased breakdown voltage of the electrode 16. It is to be understood that the distance D between at least two adjacent electrode portions 16a corresponds to the width of the insulating portion 20.

[0082] The method 100 described herein can allow for the use of a ceramic material, such as an opaque ceramic material, for the first insulating layer and the second insulating layer. Thus, the electrodes 16 can be more robust relative to electrodes that include a glass material. For example, the fracture toughness of glass is 0.8 MPa / mm 2 , while the fracture toughness of, for example, silicon nitride is about 6 MPa / mm 2 .

[0083] The electrode portions 16a and the insulating portions 20 can be formed on at least one side of the insulating layer 18 or each of the at least two opposite sides of the insulating layer 18. When the electrode portions 16a and the insulating portions 20 are formed on each of the opposite sides of the first insulating layer 18, the method includes bonding a second insulating layer 26 to the planar surface 22 of each of the opposite sides of the first insulating layer 18. Thus, the electrode portions 16a and the insulating portions 20 can be formed between the first layer 18 and a second insulating layer 26 and between the first layer 18 and another second layer 26, as shown in Figure 4 and 5

[0084] Figure 7 A flowchart is shown to outline one or more steps that can be part of the method 100 shown. Figure 6

[0085] In step 135, the method 100 can include providing or forming a plurality of first insulating layers 18, two of which are shown. Figure 7 Figure 6 The insulating layer 18 shown can be part of the plurality of first insulating layers 18.

[0086] In step 140, the method 100 can include forming at least two electrode portions 16a on each of the first insulating layers 18. The electrode portions 16a can be formed on at least one side of one or more of the first insulating layers 18 or on each of the two opposite sides of one or more of the other first insulating layers 18. In the example shown, Figure 7 the electrode portions 16a are formed on at least one side of two of the first insulating layers 18 and on each of the two opposite sides of another first insulating layer 18. The electrode portions 16a can be formed as described above in steps 110 and 115 of the method 100.

[0087] In step 145, the method 100 can include forming insulating portions 20 on each of the first insulating layers 18 between adjacent electrode portions 16a such that the insulating portions 20 fill the space 35 between two adjacent electrode portions 16a and the electrode portions 16a form a planar surface 22 with the insulating portions 20. The insulating portions can be formed as described above in steps 120 and 125 of the method 100.

[0088] In step 150, the method includes bonding the first insulating layers 18 and the at least one second insulating layer 26 together. In the example shown, Figure 7 ​​​In the illustrated example, two second insulating layers 26 are provided or formed. The first insulating layers 18 and the second insulating layers 26 can be bonded together such that the electrode portions 16a and the insulating portions 20 on each of the first insulating layers 18 are arranged between a second layer 26 and the respective first insulating layer 18, or between the respective first insulating layer 18 and another first insulating layer 18. In examples where the electrode portions 16a and the insulating portions 20 are formed on only one side of each first insulating layer 18, the first insulating layers 18 and the second insulating layers 26 can be bonded together by bonding the planar surfaces 22 on each first insulating layer 18 to another first insulating layer 18 and by bonding the planar surface 22 of one of the first insulating layers 18, e.g. the outer first insulating layer, to a second insulating layer 26. In other words, the planar surfaces 22 on each first insulating layer 18 are bonded to another first insulating layer 16 or to a second insulating layer 26, e.g. to form a stacked arrangement of electrodes 16 with electrode portions 16a.

[0089] It will be appreciated that the electrodes 16 described herein are not limited to Figure 7 the arrangements illustrated. In other embodiments, the method can include a different number and / or order of first insulating layers and / or second insulating layers.

[0090] As described above, the electrodes 16 can include vias 28. The vias 28 can be part of the first insulating layers 18 and / or the second insulating layers 26. The vias 28 can include a conductive material, such as a conductive ceramic material. The conductive ceramic material can include doped silicon nitride. The dopant or dopant material can include titanium nitride. The volume concentration of the dopant or dopant material in the silicon nitride can be between about 1% and 50%. The volume resistivity of the silicon nitride can depend on the volume concentration of the dopant or dopant material. For example, silicon nitride with a volume concentration of titanium nitride of about 35% can include a volume resistivity of about 0.6 x 10 -3 ohm cm. It will be appreciated that, in other embodiments, the vias can include a conductive glass material.

[0091] The vias 28 can be formed by locally doping the first insulating layers 18 and / or the second insulating layers 26. The first insulating layers and / or the second insulating layers can be doped using a printing process. The vias 28 can be formed in the first insulating layers 18 and / or the second insulating layers 26 prior to the sintering and / or hot pressing processes described above.

[0092] Although Figure 7 only the vias 28 in one of the first insulating layers 18 of the electrodes 16 are illustrated, it will be appreciated that one or more vias can also be provided in any of the other first insulating layers and / or second insulating layers.

[0093] The bonding step of the method 100 described above can be performed in a single bonding step, or can be performed as separate bonding steps.

[0094] It will be appreciated that any features described in relation to the method 100 can also apply to the electrode 16 described above.

[0095] The term "planar surface" can be considered to encompass the term "substantially planar surface".

[0096] It will be appreciated that reference to a plurality of features can be used interchangeably with reference to those features in the singular, such as for example "at least one" and / or "each". Features in the singular, such as for example "at least one" and / or "each" can be used interchangeably.

[0097] Although embodiments of the application have been described in relation to substrates, substrate holders and substrate tables, embodiments of the application can be used to clamp a mask MA (or other patterning device) to a support structure MT (see Figure 1 ) of a lithographic apparatus, or to clamp some other object.

[0098] Although specific reference can be made in this text to the use of lithographic apparatus in the manufacture of ICs, it should be understood that the lithographic apparatus described herein can have other applications. Possible other applications include the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat-panel displays such as liquid-crystal displays (LCDs), thin-film magnetic heads, etc.

[0099] Although specific reference can be made in this text to embodiments of the application in the context of lithography apparatus, embodiments of the application can be used in other apparatus. Embodiments of the application can form part of a mask inspection apparatus, a metrology apparatus, or any apparatus that measures or processes an object such as a wafer (or other substrate) or a mask (or other patterning device). These apparatus can be generally referred to as lithographic tools. Such lithographic tools can use vacuum conditions or ambient (non-vacuum) conditions. An object holder according to embodiments of the application can form part of a lithographic tool.

[0100] While specific embodiments of the application have been described above, it will be appreciated that the application can be practiced otherwise than as described. The description is not intended to limit the application. Accordingly, those skilled in the art will appreciate that modifications can be made without departing from the scope of the claims set forth below.

[0101] Examples 1. A method of manufacturing an electrode for an object holder, the method comprising: forming at least two electrode portions on the first insulating layer, the at least two electrode portions being spaced apart from each other; forming at least one insulating portion between the at least two electrode portions on the first insulating layer such that the at least one insulating portion fills a space between the at least two electrode portions and the at least two electrode portions form a planar surface with the at least one insulating portion; and bonding the second insulating layer to the planar surface. 2. The method according to example 1, wherein the at least two electrode portions and the at least one insulating portion have a same height. 3. The method according to example 1 or 2, wherein the at least two electrode portions and the at least one insulating portion are formed on: at least one side of the first insulating layer, or each of at least two opposite sides of the first insulating layer, wherein when the at least two electrode portions and the at least one insulating portion are formed on each of at least two opposite sides of the first insulating layer, the method comprises bonding the second insulating layer to the planar surface formed on each of the at least two opposite sides of the first insulating layer. 4. The method according to any preceding example, wherein the method comprises: forming at least two electrode portions on each of a plurality of first insulating layers; forming at least one insulating portion between the at least two electrode portions on each of the plurality of first insulating layers such that the at least one insulating portion fills a space between the at least two electrode portions and the at least two electrode portions form a planar surface with the at least one insulating portion; and bonding the plurality of first insulating layers and the second insulating layer together such that the at least two electrode portions and the at least insulating portion on each of the plurality of first insulating layers are arranged: between the second insulating layer and a respective first insulating layer of the plurality of first insulating layers, and / or between a respective first insulating layer of the plurality of first insulating layers and at least one other first insulating layer of the plurality of first insulating layers. 5. The method according to example 4, wherein the at least two electrode portions and the at least one insulating portion are formed on: at least one or each of the plurality of first insulating layers at least one side, and / or each of at least two opposite sides of at least one of the plurality of first insulating layers. 6. The method according to example 4 or 5, wherein the method comprises bonding the second insulating layer to the planar surface and / or bonding the plurality of first insulating layers and / or the second insulating layer together using at least one of: a diffusion bonding process; an anodic bonding process; a discharge plasma assisted thermal pressing process; and / or an optical contact bonding process. 7. The method according to any one of examples 4 to 6, wherein forming at least one insulating portion on the first insulating layer and / or each of the first insulating layers of the plurality of first insulating layers comprises: depositing a layer of insulating material on the at least two electrode portions and the first insulating layer and / or each of the first insulating layers of the plurality of first insulating layers; removing a portion of the layer of insulating material such that the at least two electrode portions form a planar surface with at least one remaining portion of the layer of insulating material, the at least one remaining portion forming the at least one insulating portion. 8. The method according to any one of examples 4 to 7, wherein the first insulating layer, the second insulating layer and / or at least one of the first insulating layers of the plurality of first insulating layers or each of the first insulating layers comprises a ceramic material or a glass material, the ceramic material or the glass material of at least one of the first insulating layers of the plurality of first insulating layers or each of the first insulating layers and / or the second insulating layer being the same or different to the ceramic material or the glass material of another of the first insulating layers of the plurality of first insulating layers or each of the first insulating layers and / or the second insulating layer. 9. The method according to any preceding example, wherein the at least two electrode portions comprise an electrically conductive material and the at least one insulating portion comprises an insulating material, the insulating material having a hardness that is less than a hardness of the electrically conductive material. 10. The method according to example 9, wherein the electrically conductive material comprises at least one of: an electrically conductive ceramic material, a semiconducting material and doped diamond; and / or wherein the insulating material comprises at least one of: a quartz material, a glass material and / or a ceramic material. 11. The method according to any one of examples 4 to 10, wherein the first insulating layer, at least one of the plurality of first insulating layers and / or the second insulating layer comprises one or more electrically conductive portions arranged to electrically connect: one or more respective electrode portions of the at least two electrode portions arranged with each other or formed on each of at least two opposing sides of the first insulating layer and / or at least one of the first insulating layers of the plurality of first insulating layers; and / or one or more electrode portions of the at least two electrode portions formed with or arranged on the first insulating layer and / or at least one of the first insulating layers of the plurality of first insulating layers together with another portion or component of the object holder.

Claims

1. A method of manufacturing an electrode for an object holder, the method comprising: forming at least two electrode portions on a first insulating layer, the at least two electrode portions being spaced apart from each other; forming at least one insulating portion on the first insulating layer, between the at least two electrode portions, such that the at least one insulating portion fills a space between the at least two electrode portions, and the at least two electrode portions form a planar surface with the at least one insulating portion; and bonding a second insulating layer to the planar surface.

2. The method of claim 1, wherein the at least two electrode portions and the at least one insulating portion have a same height.

3. The method of claim 1 or 2, wherein the at least two electrode portions and the at least one insulating portion are formed on: at least one side of the first insulating layer, or each of at least two opposite sides of the first insulating layer, wherein when the at least two electrode portions and the at least one insulating portion are formed on each of the at least two opposite sides of the first insulating layer, the method comprises bonding a second insulating layer to the planar surface formed on each of the at least two opposite sides of the first insulating layer.

4. The method of any preceding claim, wherein the method comprises: forming at least two electrode portions on each of a plurality of first insulating layers; forming at least one insulating portion on each of the plurality of first insulating layers, between the at least two electrode portions, such that the at least one insulating portion fills a space between the at least two electrode portions, and the at least two electrode portions form a planar surface with the at least one insulating portion; and bonding the plurality of first insulating layers and the second insulating layer together, such that the at least two electrode portions and the at least insulating portion on each of the plurality of first insulating layers are arranged: between the second insulating layer and a respective first insulating layer of the plurality of first insulating layers, and / or between the respective first insulating layer of the plurality of first insulating layers and at least one other first insulating layer of the plurality of first insulating layers.

5. The method of claim 4, wherein the at least two electrode portions and the at least one insulating portion are formed on: at least one or each first insulating layer of the plurality of first insulating layers at least one side, and / or each of at least two opposite sides of at least one first insulating layer of the plurality of first insulating layers.

6. The method of claim 4 or 5, wherein the method comprises bonding the second insulating layer to the planar surface and / or bonding the plurality of first insulating layers and / or the second insulating layer together using at least one of: a diffusion bonding process; an anodic bonding process; a discharge plasma assisted thermal compression process; and / or an optical contact bonding process. ​ ​ 7. The method according to any one of claims 4 to 6, wherein forming the at least one insulating portion on the first insulating layer and / or each of the plurality of first insulating layers comprises: depositing a layer of insulating material on the at least two electrode portions and the first insulating layer and / or each of the plurality of first insulating layers; removing a portion of the layer of insulating material such that the at least two electrode portions form the planar surface with at least one remaining portion of the layer of insulating material forming the at least one insulating portion.

8. The method according to any one of claims 4 to 7, wherein the first insulating layer, the second insulating layer and / or at least one or each of the plurality of first insulating layers comprises a ceramic material or a glass material, the ceramic material or glass material of at least one or each of the first insulating layer, the plurality of first insulating layers and / or the second insulating layer being the same or different to the ceramic material or glass material of at least one other of the first insulating layer, the plurality of first insulating layers and / or the second insulating layer.

9. An electrode for an object holder, comprising: at least two electrode portions arranged on a first insulating layer, the at least two electrode portions being spaced apart from each other; at least one insulating portion arranged on the first insulating layer between the at least two electrode portions such that the at least one insulating portion fills a space between the at least two electrode portions and the at least two electrode portions form a planar surface with the at least one insulating portion; and a second insulating layer bonded to the planar surface.

10. The electrode according to claim 9, wherein the at least two electrode portions and the at least one insulating portion are arranged on at least one side of the first insulating layer or each of at least two opposing sides of the first insulating layer, wherein when the at least two electrode portions and the at least one insulating portion are arranged on each of the at least two opposing sides of the first insulating layer, a second insulating layer is bonded to the planar surface formed on each of the at least two opposing sides of the first insulating layer.

11. The electrode according to claim 9 or 10, wherein electrode comprises: a plurality of first insulating layers, the at least two electrode portions being arranged on each of the plurality of first insulating layers; at least one insulating portion arranged on each of the plurality of first insulating layers between the at least two electrode portions such that the at least one insulating portion fills a space between the at least two electrode portions and the at least two electrode portions form a planar surface with the at least one insulating portion; and a second insulating layer bonded to the planar surface. ​ wherein the plurality of first insulating layers and the second insulating layer are bonded together such that the at least two electrode portions and the at least one insulating portion on each of the plurality of first insulating layers are arranged: between the second insulating layer and a respective one of the plurality of first insulating layers, and / or between the respective one of the plurality of first insulating layers and at least one other of the plurality of first insulating layers.

12. An object holder configured to support an object, the object comprising an electrode according to any one of claims 9 to 11.

13. A stage comprising an object holder according to claim 12.

14. A lithographic apparatus comprising: a lithographic system; a projection system; and a stage according to claim 13.

15. A semiconductor processing tool comprising a stage according to claim 13. ​

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