Object stage

Abstract

A stage includes: a base portion having a flat surface; a substrate support or patterning device support, the substrate support or patterning device support comprising a clamp and a set of tabs, the tabs extending from the clamp and having a distal end adjacent to the planar surface of the base; wherein the stage further comprises: a compliant layer, the compliant layer being disposed between the distal end of the burst node and the flat surface of the base; and a friction layer in contact with the compliant layer.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to European Application No. 22216468.3, filed on December 23, 2022, the entire content of which is incorporated herein by reference. Technical field

[0003] The present invention relates to a stage. The stage can form a component of a lithographic apparatus. Background art

[0004] A lithographic apparatus is a machine configured 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 can, for example, project a pattern provided on a patterning device (e.g., a mask) onto a layer of radiation-sensitive material (resist) provided on a substrate.

[0005] In order to project a pattern onto a substrate, a lithographic apparatus can use electromagnetic radiation. The wavelength of this radiation determines the minimum size of the features that can be formed on the substrate. Compared to a lithographic apparatus using radiation having a wavelength of, for example, 193 nm, a lithographic apparatus using extreme ultraviolet (EUV) radiation having a wavelength in the range of 4 nm to 20 nm (e.g., 6.7 nm or 13.5 nm) can be used to form smaller features on a substrate.

[0006] The substrate patterned by the lithographic apparatus is held on a stage. The stage includes a substrate table configured to firmly hold the substrate on the stage when the substrate is being patterned and then to allow removal of the substrate from the substrate table once patterning has been completed. The stage also includes a base that couples the substrate table to means for controlling the position and speed of the stage. In some lithographic apparatuses, the base can be a mirror block (i.e., including mirrors on its sides) in order to enable interferometry. The substrate table typically abuts against the base via protruding nodules. A problem that can arise with the stage is that it can be difficult to ensure that the substrate table is clamped strongly enough to avoid sliding or relative displacement of the nodules on the base during high acceleration of the stage. If sliding of the nodules occurs during acceleration, then after acceleration, the distal end of the sliding nodule will be displaced from its original position. This will cause deformation of the substrate held on the substrate table. Even deformations on the nanometer length scale are disadvantageous for the operation of the lithographic apparatus. The deformation can result in the formation of a poor-quality pattern on the substrate.

[0007] The stage can also be used to firmly hold a patterning device in a lithographic apparatus. When holding the patterning device, the stage can suffer from the same problems.

[0008] It may be desirable to solve the above problems in a manner not disclosed or suggested by the prior art. SUMMARY OF THE INVENTION

[0009] According to a first aspect of the present invention, there is provided a stage comprising: a base having a flat surface; a substrate support or a patterning device support including a clamp and a set of bosses extending from the clamp and having distal ends adjacent to the flat surface of the base; wherein the stage further comprises: a compliant layer disposed between the distal ends of the bosses and the flat surface of the base; and a friction layer in contact with the compliant layer.

[0010] Advantageously, the compliant layer allows the bosses to withstand deformation of the base under high acceleration. Since the compliant layer exhibits significant lateral compliance under normal force, the deformation of the base can be withstood. Thus, the bosses can elastically conform or adapt to the deformation of the base without the bosses and the base sliding relative to each other.

[0011] Further advantageously, the friction layer increases the force for the surfaces between which the friction layer is disposed to translate and slide relative to each other.

[0012] The compliant layer may be disposed on the distal ends of the bosses.

[0013] Advantageously, this saves material usage and time in manufacturing as the area of the distal ends of the bosses is relatively small.

[0014] The compliant layer can be deposited by physical vapor deposition, chemical vapor deposition or sputter deposition.

[0015] The compliant layer may be disposed on the flat surface of the base.

[0016] The friction layer may be disposed on the flat surface of the base.

[0017] The friction layer may be disposed on the distal ends of the bosses.

[0018] The friction layer may be disposed on the compliant layer.

[0019] The stage may further comprise an additional compliant layer disposed on the flat surface of the base.

[0020] The stage may further comprise an additional compliant layer disposed on the distal ends of the bosses.

[0021] The friction layer may be disposed on the additional compliant layer.

[0022] Advantageously, a plurality of compliant layers are provided between components of the stage to reduce the effective shear strain for a given linear displacement relative to the nodules, thereby enhancing compliance with respect to base deformation.

[0023] Advantageously, this reduces the risk of slippage of the compliant layer and adjacent surfaces such as the base.

[0024] According to a second aspect of the present invention, there is provided an object support for placement on a base, comprising a clamp and a set of nodules extending from the clamp, wherein a compliant layer is provided on the distal ends of the nodules.

[0025] The compliant layer may have an effective shear modulus of less than 100 GPa.

[0026] This relatively low shear modulus (and thus low lateral stiffness) of one or more compliant layers allows the substrate stage to more easily conform or comply with base deformation by shear deformation.

[0027] The compliant layer may have a shear modulus of at least 1 GPa.

[0028] The porosity of the compliant layer may be at least 5%.

[0029] Advantageously, the porosity of the compliant layer material microstructure enhances the compliance of the material relative to its bulk state by reducing the effective shear modulus (in other words, the lateral stiffness). By selecting the porosity of the compliant layer, the desired compliance can be obtained.

[0030] The compliant layer may have a porosity of up to 30%.

[0031] The porous compliant layer also offers the advantage of adsorbing small contaminant particles into the porous microstructure of the compliant layer. Thus, within limits, the sensitivity of the stage to flatness defects caused by small particles is reduced.

[0032] The compliant layer may consist essentially of a transition metal nitride.

[0033] The compliant layer may consist of a doped transition metal nitride.

[0034] Advantageously, many transition metal nitrides (specifically, groups 4, 5, and 6 transition metals including chromium nitride) are particularly thermally stable, corrosion resistant, and wear resistant. In particular, chromium nitride that can be used is relatively abundant and easy to transport in manufacturing.

[0035] The compliant layer may have a substantially fibrous microstructure consisting of a plurality of fibril-like grains.

[0036] A plurality of substantially columnar elements may extend in a direction substantially perpendicular to the plane of the base or substantially perpendicular to the plane of the substrate support or the patterning device support.

[0037] The columnar microstructure may be a serrated microstructure.

[0038] Advantageously, the compliant layer having columnar or serrated elements has high lateral compliance and relatively high normal rigidity in order to support normal force loads.

[0039] The thickness of the compliant layer may be at least 0.1 μm.

[0040] The thickness of the compliant layer allows for a desired degree of lateral compliance while allowing for ready fabrication, for example, by thin film sputter deposition. The compliant layer may have a thickness of up to 100 μm and preferably has a thickness between approximately 1 μm and 10 μm.

[0041] The friction layer may have a coefficient of static friction greater than 0.1.

[0042] Advantageously, the relatively high dimensionless coefficient of static friction of the friction layer can prevent relative translational movement or sliding between the studs and the base at high accelerations (e.g., 100 ms -2 or 200 ms -2 ). The friction layer may have a coefficient of static friction of 0.2 or greater.

[0043] The friction layer may consist essentially of a transition metal nitride.

[0044] The friction layer may consist essentially of tungsten nitride.

[0045] The friction layer may consist essentially of titanium nitride.

[0046] Advantageously, both tungsten nitride and titanium nitride exhibit high wear resistance and a high coefficient of static friction and are capable of strongly adhering to the underlying surface.

[0047] The friction layer may have a thickness of at least 50 nm.

[0048] The friction layer may have a thickness of up to 5000 nm. The friction layer may have a thickness of approximately 200 nm to 1000 nm.

[0049] Advantageously, a friction layer having a thickness of at least 50 nm allows for the use of a planarization process, thereby reducing the risk of flatness defects in the fixture and elsewhere.

[0050] According to a second aspect of the invention, there is provided a method of manufacturing a stage suitable for use in a lithographic apparatus, comprising: providing a base having a flat surface; providing a substrate support or patterning device support including a clamp and a set of protrusions extending from the clamp and having distal ends adjacent to the flat surface of the base; and further providing a compliant layer disposed between the distal ends of the protrusions and the flat surface of the base and a friction layer in contact with the compliant layer.

[0051] The compliant layer may be deposited by physical vapor deposition.

[0052] The friction layer may be deposited by physical vapor deposition.

[0053] Features of different aspects of the invention may be combined. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which:

[0055] - Figure 1 A lithographic system including a lithographic apparatus and a radiation source is schematically depicted;

[0056] - Figure 2 A stage according to an embodiment of the invention is schematically depicted in cross-section;

[0057] - Figure 3 A partial view of a part of the stage is schematically depicted in cross-section;

[0058] - Figure 4 A partial view of the part of the stage in acceleration is schematically depicted in cross-section; Figure 3 of

[0059] - Figure 5A A part of a stage according to an alternative embodiment of the invention is schematically depicted in cross-section;

[0060] - Figure 5B A part of a stage according to an alternative embodiment of the invention is schematically depicted in cross-section;

[0061] - Figure 5C A part of a stage according to an alternative embodiment of the invention is schematically depicted in cross-section;

[0062] - Figure 6A A part of a stage according to an alternative embodiment of the invention is schematically depicted in cross-section;

[0063] - Figure 6B A part of a stage according to an alternative embodiment of the invention is schematically depicted in cross-section; and

[0064] - Figure 7 A part of a stage according to an embodiment of the present invention is schematically depicted in cross-section and with more detail. Detailed description of specific embodiments

[0065] Figure 1 A lithography system including a radiation source SO and a lithography apparatus LA is shown. The radiation source SO is configured to generate an EUV radiation beam B and supply the EUV radiation beam B to the lithography apparatus LA. The lithography apparatus LA includes an illumination system IL, a patterning device stage MT configured to support a patterning device MA (e.g., a mask), a projection system PS, and a substrate stage WT configured to support a substrate W. The patterning device stage MT and the substrate stage WT can be examples of a stage according to an embodiment of the present invention.

[0066] The illumination system IL is configured to condition the EUV radiation beam B before the EUV radiation beam B is incident on the patterning device MA. Additionally, the illumination system IL can include a faceted field mirror device 10 and a faceted pupil mirror device 11. The faceted field mirror device 10 and the faceted pupil mirror device 11 together provide a desired cross-sectional shape and a desired intensity distribution to the EUV radiation beam B. In addition to or instead of the faceted field mirror device 10 and the faceted pupil mirror device 11, the illumination system IL can also include other mirrors or devices.

[0067] After being conditioned in this way, the EUV radiation beam B interacts with the patterning device MA. Due to 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 configured to project the patterned EUV radiation beam B’ onto the substrate W held by the substrate stage WT. The projection system PS can apply a reduction factor to the patterned EUV radiation beam B’, thereby forming an image with features smaller than the 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 in Figure 1 as having only two mirrors 13, 14, the projection system PS can include a different number of mirrors (e.g., six or eight mirrors).

[0068] The substrate W can include a previously formed pattern. In such a case, the lithography apparatus LA aligns the image formed by the patterned EUV radiation beam B’ with the pattern previously formed on the substrate W.

[0069] A relative vacuum can be provided in the radiation source SO, in the illumination system IL, and / or in the projection system PS, i.e., a small amount of gas (e.g., hydrogen gas) at a pressure far below atmospheric pressure.

[0070] The radiation source SO can be a laser-produced plasma (LPP) source, a discharge-produced plasma (DPP) source, a free electron laser (FEL), or any other radiation source capable of generating EUV radiation.

[0071] Figure 2 Schematically depicted in cross-section Figure 1 a portion of one of the stages (in this case, the substrate stage WT1). The stage includes a base 20 having a flat surface 22 and a substrate support 24. The substrate support 24 includes a clamp 26 and a set of bosses 28. The bosses extend from the clamp 26 and have distal ends 29 adjacent to and forming a free interface with the flat surface 22 of the base 20. The bosses 28 can form a free interface with the base 20. For clarity, only one boss is labeled.

[0072] Here, the free interface is used to refer to an interface that does not have tensile cohesion.

[0073] The base 20 can be made substantially of a glass material. The glass material can be, for example, cordierite or Zerodur (a glass-ceramic available from Schott AG, Mainz, Germany). The base 20 can have a low coefficient of thermal expansion. The substrate support 24 (including the bosses 28) can be made substantially of silicon carbide (SiSiC) or XG glass (available from Corning Incorporated, New York, USA). The substrate support 24 can have a low coefficient of thermal expansion.

[0074] Figure 3 A detailed view shows one boss 28 and adjacent portions of the base 20 and the clamp 26. It will be appreciated that the other bosses will be substantially the same as this boss. The boss 28 includes a compliant layer 30 located on the distal end 29 of the boss and a friction layer 32 located on the compliant layer. Thus, the depicted arrangement provides a compliant layer 30 between the distal end 29 of the boss and the flat surface 22 of the base 20.

[0075] The friction layer 32 forms a free interface with the flat surface 22 of the base 20. It will be appreciated that the free interface is an interface where only frictional forces act.

[0076] When the clamp is actuated or made operative, the clamp presses the boss 28 (and the other bosses) against the base 20. The substrate support 24 is thereby fastened to the base 20.

[0077] The compliant layer 30 is characterized in that it has a relatively low shear modulus between 1 GPa and 100 GPa. The compliant layer may have a thickness between 0.1 μm and 100 μm. Preferably, the compliant layer has a thickness between 1 μm and 10 μm. The compliant layer may allow a lateral displacement or deflection of about 20 nm before sliding.

[0078] The low shear modulus and high compliant layer thickness (e.g., the above values) reduce the effective shear strain for a given linear displacement with respect to the nodule, thereby enhancing the compliance to base deformation. The compliant layer is capable of elastically conforming or complying with the deformation of the base 20.

[0079] The compliant layer 30 may have a normal stiffness of at least about 5×10 6 N / m, for example up to about 5×10 8 N / m. The compliant layer 30 may preferably have a normal stiffness of 5×10 7 N / m to 7×10 7 N / m. The relatively high normal stiffness allows the compliant layer 30 to support the substrate and the substrate support 26.

[0080] One way to achieve the desired shear modulus of the compliant layer is by selecting the porosity of the compliant layer. The porosity of the compliant layer may be at least 5%. A porosity of 5% may be sufficient to provide a significant degree of lateral compliance. Higher porosity will provide a greater degree of lateral compliance and may therefore be desirable (e.g., depending on the acceleration level the stage will experience). The porosity of the compliant layer may be at least 10%, and may be at least 15%. The porosity of the compliant layer may be as high as 30%.

[0081] The porosity of the compliant layer can be achieved by using a fibrous microstructure. Referring to Figure 7 , which schematically depicts an embodiment of a stage having a compliant layer 30, the compliant layer may have a fibrous microstructure including fiber-like grains 40 (or fibers) having a generally linear shape. The fibers 40 extend in a direction generally perpendicular to the plane of the substrate support (i.e., generally away from the distal end of the nodule). The fibers define gaps 41, thereby providing the desired porosity to the compliant layer.

[0082] It will be appreciated that there are many other available porous microstructures. The microstructure of any deposited material can be controlled to provide a set of desired properties, such as a low (lateral) shear modulus and / or a high coefficient of static friction.

[0083] In an alternative embodiment, the compliant layer 30 may have a "sawtooth" microstructure including a plurality of "sawtooth" members, each member being similar to a sawtooth wave. The "sawtooth" members may extend generally perpendicular to the plane of the substrate support.

[0084] In the presently described embodiments, the compliant layer 30 and / or the friction layer 32 can be composed of, for example, transition metal nitrides such as tungsten nitride, tantalum nitride, titanium nitride, or chromium nitride, or doped forms thereof. These transition metal nitrides are well-suited for the present application as they are thermally stable, wear-resistant, and corrosion-resistant.

[0085] The friction layer 32 can be characterized in that it can provide an interface with a relatively high coefficient of static friction. For example, the coefficient of static friction can be at least 0.1, can be, for example, 0.14, and preferably can be 0.2 or greater. A coefficient of static friction of 0.1 can be sufficient to prevent slipping at high accelerations, but a coefficient of static friction of 0.14 or more preferably 0.2 provides greater anti-slip properties and / or prevents slipping at even greater accelerations.

[0086] The thickness of the friction layer 32 can be in the range of 50 nm to 5000 nm, preferably in the range of 200 nm to 1000 nm.

[0087] The friction layer 32 can be formed of the same material as the compliant layer, but with a different microstructure. For example, instead of the fibrous structure of the compliant layer 30, the friction layer 32 can have a columnar grain or nanocrystalline fine grain microstructure.

[0088] The friction layer can be provided by means of different compositions (e.g., chemical surface treatment) or by surface engineering treatment methods (e.g., plasma treatment).

[0089] During the manufacture of the stage, the friction layer 32 can be subjected to a planarization operation, such as polishing, in order to provide the desired flatness of the bottom of the substrate stage. Such an operation is a subtractive operation. This can impose a minimum thickness of about 50 nm on the friction layer (as stated above), and makes layers with a thickness greater than 50 nm more attractive in terms of manufacture.

[0090] The friction layer 32 can be composed of a transition metal nitride, which can be chemically equivalent or not equivalent to the compliant layer 30, for example, can be tungsten nitride or titanium nitride. These transition metal nitrides are well-suited for the present application as they are wear-resistant and have good cohesion or adhesion with the compliant layer 30.

[0091] By varying process variables during deposition, the microstructure configuration and thickness of any deposited layer (e.g., the compliant layer and / or the friction layer) can be controlled. For example, a material layer such as a transition metal nitride can be deposited on a surface by means of physical vapor deposition (PVD). Columnar, fibrous, or fine grain nanocrystalline microstructures can be deposited by selecting process parameters. PVD process parameters include ambient composition, temperature, and plasma energy.

[0092] Other layer deposition methods, such as chemical vapor deposition (CVD), can also be used.

[0093] Reference is now made to Figure 4 the use according to an embodiment of the present invention. The embodiment is described in connection with a substrate on a substrate table. However, equivalent embodiments apply to a patterning device on a patterning device table.

[0094] Load the substrate onto the substrate support 24. Then electrostatically clamp the substrate support and the substrate so as to fasten them in place during movement and acceleration of the stage and the substrate. The clamping fastens the substrate (not depicted) to the substrate support 24. Additionally, the clamping fastens the substrate support 24 to the base 20. In both cases, a compressive clamping force is applied that is directed substantially perpendicular to the flat surface 22 of the base 20. The compressive clamping force between the substrate support 24 and the base 20 results in a high friction threshold against relative movement between the base 20 and the substrate support 24.

[0095] A high acceleration of the stage including the base 20 is desirable in order to increase the throughput of a lithographic apparatus such as LA.

[0096] In use, at high stage accelerations, deformation of the base 20 occurs. The deformation of the base 20 may force the protrusion to deflect or slide under the normal clamping force. Here, the high acceleration can be, for example, about 40 ms -2 about 100 ms -2 or about 200 ms -2 .

[0097] The protrusion 28 deflects so as to conform or accommodate to the deformation of the base 20. The deflection causes a lateral restoring force in the protrusion. The lateral restoring force increases with the deflection.

[0098] Sliding can be understood as the situation where the deflection of the protrusion 28 reaches the point where the lateral restoring force of the protrusion exceeds the static friction force maintaining static contact with a portion of the flat base. There is no longer static equilibrium, and thus relative movement or sliding occurs between the distal end 29 of the protrusion and the flat surface 22 of the base.

[0099] Figure 4 Schematically illustrates the protrusion 28 at a deflection Δ, and also depicts the adjacent portions of the base 20 and the clamp 26. When the stage is stationary, the configurations of the same protrusion and the adjacent portion of the clamp 26 are superimposed (semi-transparent, 28a and 26a respectively) in order to illustrate the nature of the deformation. The lateral restoring force in the protrusion is labeled F R .

[0100] Depending on the characteristics of the base deformation, the deflection of the knuckle can vary. Due to the relatively low shear modulus of the compliant layer 30 (compared to a conventional arrangement without a compliant layer), the provision of the compliant layer 30 reduces the lateral force F for a given knuckle deflection value Δ R The reduced lateral force F caused by knuckle deflection for a given deflection value Δ R means an increased deflection value to overcome static friction. A greater deflection and thus a greater base deformation are required to cause sliding. In other words, sliding is less likely to occur.

[0101] For a given normal clamping force, the friction layer increases the force threshold for sliding. Thus, the compliant layer and the friction layer cooperate in combination to increase the force at which sliding occurs. Consequently, the stage of the present invention can withstand higher accelerations without the knuckles sliding.

[0102] It will be appreciated that the present invention is not limited to the embodiments described above. In fact, there can be many variations in structure and composition, some of which are presented below.

[0103] It will be appreciated that the following alternative embodiments are comparable in structure and composition to the embodiments Figures 2 to 4 described with reference. Thus, where appropriate, the same reference numerals will refer to the same elements.

[0104] Figure 5A Another embodiment of the present invention is schematically illustrated. It shows a detailed view of the adjacent parts of the knuckle 28 and the base 20. It will be appreciated that other instances of the knuckle can be substantially the same. The compliant layer 30 is provided on the flat surface 22 of the base 20, and the friction layer 32 is provided on the compliant layer.

[0105] The friction layer 32 forms a free interface with the distal end 29 of the knuckle 28.

[0106] Figure 5B Another embodiment of the present invention is schematically illustrated. It shows a detailed view of the adjacent parts of the knuckle 28 and the base 20. The compliant layer 30 is provided on the distal end 29 of the knuckle 28, and the friction layer 32 is provided on the flat surface 22 of the base 20.

[0107] The friction layer 32 forms a free interface with the compliant layer 30.

[0108] Figure 5C Another embodiment of the present invention is schematically illustrated. It shows a detailed view of the adjacent parts of the knuckle 28 and the base 20. The friction layer 32 is provided on the distal end 29 of the knuckle 28, and the compliant layer 30 is provided on the flat surface 22 of the base 20.

[0109] The friction layer 32 forms a free interface with the compliant layer 30.

[0110] In some alternative embodiments, the stage may include a plurality of compliant layers, for example, two compliant layers.

[0111] Figure 6A An alternative embodiment having two compliant layers is schematically illustrated in Figure 6A A detailed view showing adjacent portions of the knuckle 28 and the base 20. A first compliant layer 30a is disposed on the flat surface 22 of the base 20, and a friction layer 32 is disposed on the first compliant layer 30a. A second compliant layer 30b is disposed on the flat surface 22 of the base 20.

[0112] The friction layer 32 may also be disposed on the second compliant layer 30b, as Figure 6B shown in

[0113] or even on both the first and second compliant layers.

[0114] Generally, the embodiments described with reference to Figures 5A to 6B achieve their functions in substantially the same manner (e.g., as the functions described with respect to Figure 4 ). By providing the compliant layers, the deflection force is reduced. By providing the friction layer at the free interface, the deflection force necessary for sliding is increased. Thus, the effects of the friction layer and the compliant layers are synergistic in increasing the acceleration tolerance of the stage.

[0115] Embodiments of the present invention relate to compliant layers disposed on structures such as the distal end of a knuckle. The compliant layers may be provided by deposition or any other suitable process. Embodiments of the present invention relate to friction layers disposed on structures such as the flat surface of a base. The friction layers may be provided by deposition or any other suitable process.

[0116] Although the embodiments described above are mainly described with respect to their use in EUV lithography equipment, it will be appreciated that the stages described above may also be applicable, for example, in deep ultraviolet (DUV) lithography equipment.

[0117] Although the lithography equipment may be specifically referred to herein with respect to its use in IC manufacturing, it should be understood that the lithography equipment described herein may have other applications. Possible other applications include manufacturing integrated optical systems, guiding and detecting patterns for magnetic domain memories, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads, and the like.

[0118] Although specific embodiments of the invention may be referred to herein specifically in the context of a lithographic apparatus, embodiments of the invention can be used in other apparatuses. Embodiments of the invention can form part of a mask inspection apparatus, a metrology apparatus or any apparatus for measuring or processing an object such as a wafer (or other substrate) or a mask (or other patterning device). Such apparatuses are often referred to as lithographic tools. Such lithographic tools can operate in vacuum conditions or ambient (non-vacuum) conditions.

[0119] Although the above may have specifically referred to the use of embodiments of the invention in the context of optical lithography, it will be appreciated that, where the context allows, the invention is not limited to optical lithography and can be used in other applications such as, for example, imprint lithography.

[0120] Although specific embodiments of the invention have been described above, it will be appreciated that the invention can be practiced in other ways different from those described. The above description is intended to be illustrative and not restrictive. Thus, those skilled in the art will appreciate that the described invention can be modified without departing from the scope of the claims set forth below.

[0121] Examples

[0122] 1. A stage, comprising:

[0123] A base having a flat surface;

[0124] A substrate support or a patterning device support, the substrate support or the patterning device support comprising:

[0125] A clamp and a set of protrusions extending from the clamp and having distal ends adjacent to the flat surface of the base;

[0126] Wherein the stage further comprises:

[0127] A compliant layer disposed between the distal ends of the protrusions and the flat surface of the base; and

[0128] A friction layer in contact with the compliant layer.

[0129] 2. The stage according to Example 1, wherein the compliant layer is disposed on the distal ends of the protrusions.

[0130] 3. The stage according to Example 1, wherein the compliant layer is disposed on the flat surface of the base.

[0131] 4. The stage according to Example 2, wherein the friction layer is disposed on the flat surface of the base.

[0132] 5. The stage according to Example 3, wherein the friction layer is provided on the distal end of the protrusion.

[0133] 6. The stage according to Example 2 or 3, wherein the friction layer is provided on the compliant layer.

[0134] 7. The stage according to Example 2, further comprising an additional compliant layer provided on the flat surface of the base.

[0135] 8. The stage according to Example 3, further comprising an additional compliant layer provided on the distal end of the protrusion.

[0136] 9. The stage according to Example 7 or 8, wherein the friction layer is provided on the additional compliant layer.

[0137] 10. The stage according to any one of the preceding examples, wherein the compliant layer has an effective shear modulus of less than 100 GPa.

[0138] 11. The stage according to any one of the preceding examples, wherein the porosity of the compliant layer is at least 15%.

[0139] 12. The stage according to any one of the preceding examples, wherein the compliant layer is substantially composed of a transition metal nitride.

[0140] 13. The stage according to any one of the preceding examples, wherein the compliant layer is composed of a doped transition metal nitride.

[0141] 14. The stage according to any one of the preceding examples, wherein the compliant layer has a substantially fibrous microstructure composed of a plurality of fiber-like grains.

[0142] 15. The stage according to Example 14, wherein a plurality of substantially columnar elements extend in a direction substantially perpendicular to the plane of the base or the plane substantially perpendicular to the substrate support or the patterning device support.

[0143] 16. The stage according to Example 14 or Example 15, wherein the columnar microstructure is a zigzag microstructure.

[0144] 17. The stage according to any one of Examples 12 to 16, wherein the thickness of the compliant layer is at least 0.1 μm.

[0145] 18. The stage according to any one of the preceding examples, wherein the friction layer has a static friction coefficient greater than 0.1.

[0146] 19. The stage according to any one of the preceding examples, wherein the friction layer is substantially composed of a transition metal nitride.

[0147] 20. The stage according to Example 19, wherein the friction layer is substantially composed of tungsten nitride.

[0148] 21. The stage according to Example 19, wherein the friction layer is substantially composed of titanium nitride.

[0149] 22. The stage according to any one of Examples 19 to 21, wherein the friction layer has a thickness of at least 50 nm.

[0150] 23. A method of manufacturing a stage suitable for use in a lithographic apparatus, comprising:

[0151] providing a base having a flat surface;

[0152] providing a substrate support or a patterning device support, the substrate support or the patterning device support comprising:

[0153] a clamp and a set of protrusions extending from the clamp and having distal ends adjacent to the flat surface of the base; and

[0154] the method further comprising providing:

[0155] a compliant layer disposed between the distal ends of the protrusions and the flat surface of the base; and

[0156] a friction layer in contact with the compliant layer.

Claims

1. A stage, comprising: A base having a flat surface; A substrate support or a patterning device support, the substrate support or the patterning device support comprising: A clamp and a set of protrusions extending from the clamp and having distal ends adjacent to the flat surface of the base; Wherein, the stage further comprises: A compliant layer disposed between the distal ends of the protrusions and the flat surface of the base; and A friction layer in contact with the compliant layer.

2. The stage according to claim 1, wherein, The compliant layer is disposed on the distal ends of the protrusions.

3. The stage according to claim 1, wherein, The compliant layer is disposed on the flat surface of the base.

4. The stage according to claim 2, wherein The friction layer is disposed on the flat surface of the base.

5. The stage according to claim 3, wherein, The friction layer is disposed on the distal ends of the protrusions.

6. The stage according to claim 2 or 3, wherein The friction layer is disposed on the compliant layer.

7. An object support for placement on a base, comprising a clamp and a set of nodules extending from said clamp, wherein, The compliant layer is disposed on the distal ends of the protrusions, and the object support is for semiconductor manufacturing equipment.

8. The stage or object support according to any one of the preceding claims, wherein, The compliant layer has an effective shear modulus of less than 100 GPa, or / and wherein the porosity of the compliant layer is at least 5%.

9. The stage or object support according to any one of the preceding claims, wherein, The compliant layer is substantially composed of a transition metal nitride or a doped transition metal nitride, and wherein the compliant layer has a substantially fibrous microstructure composed of a plurality of fiber-like grains.

10. The stage or object support according to claim 9, wherein, A plurality of substantially columnar elements extend in a direction substantially perpendicular to the plane of the base or the plane of the substrate support or the patterning device support. Optionally, wherein the columnar microstructure is a zigzag microstructure.

11. The stage or object support according to any one of claims 9 to 10, wherein, The thickness of the compliant layer is at least 0.1 μm, or / and Wherein, the friction layer has a static friction coefficient greater than 0.

1.

12. The stage or object support according to any one of the preceding claims, wherein, The friction layer is substantially composed of a transition metal nitride.

13. The stage or object support according to claim 12, wherein, The friction layer is substantially composed of tungsten nitride or titanium nitride.

14. The stage or object support according to any one of claims 12 to 13, wherein, The friction layer has a thickness of at least 50 nm.

15. A semiconductor manufacturing equipment, comprising the stage or the object support according to any one of the preceding claims.

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