Apparatus for conditioning a component of a lithography apparatus and related method and lithographic apparatus

Abstract

This invention provides an apparatus for conditioning an assembly of a lithography device, the apparatus comprising: a housing configured to contain a hydrogen plasma; a hydrogen plasma generator configured to supply the hydrogen plasma to the assembly; wherein the apparatus is configured to control at least one of the following: the ratio of hydrogen ions to hydrogen radicals in the hydrogen plasma, the distance between the housing and the conditioned assembly, and the energy of the plasma. Also described is a method for conditioning a surface of an assembly of a lithography device, a lithography device, and the use of such an apparatus or method in a lithography device or process.

Description

[Technical Field]

[0001] This invention relates to an apparatus for adjusting components of a lithography apparatus, a method for adjusting components of a lithography apparatus, a lithography apparatus including an apparatus for adjusting components of a lithography apparatus, and the use of this apparatus or method in a lithography apparatus or method. This invention also relates to a method for processing wafer abutments or wafers, and such processed wafer abutments and wafers. This invention has specific, but not necessarily exclusive, applications in EUV lithography. [Previous Technology]

[0002] A lithography apparatus is a machine configured to coat a desired pattern onto a substrate. Lithography apparatuses can be used, for example, in the manufacture of integrated circuits (ICs). A lithography apparatus can, for example, project a pattern at a patterned device (e.g., a photomask) onto a radiation-sensitive material (resist) layer disposed on a substrate.

[0003] To project a pattern onto a substrate, a lithography apparatus may use electromagnetic radiation. The wavelength of this radiation determines the minimum size of the feature that can be formed on the substrate. Compared to a lithography apparatus using radiation with a wavelength of, for example, 193 nm, a lithography apparatus using extreme ultraviolet (EUV) radiation with 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 the substrate. [Summary of the Invention]

[0004] According to a first aspect of the present invention, an apparatus for adjusting an assembly of a lithography device is provided, the apparatus comprising: a housing configured to contain a hydrogen plasma; a hydrogen plasma generator configured to supply a hydrogen plasma to the assembly; wherein the apparatus is configured to control at least one of the following: the ratio of hydrogen ions to hydrogen radicals in the hydrogen plasma, the distance between the housing and the adjusted assembly, and the energy of the plasma.

[0005] Within lithography apparatuses, pressure is extremely low, and under certain conditions, surfaces may lack passivation. For example, a wafer stage contains an array of protrusions on which the wafer is placed during imaging. Protrusions are essentially small pillars supporting the wafer. The friction between the protrusions and the wafer varies depending on the conditions, resulting in what is known as the wafer load grid, which is the load distribution on the wafer. A hydrophobic material is required between the protrusions and the wafer to reduce friction or otherwise reduce the frictional effects between the two surfaces. Specifically, the hydrophobic material reduces the adhesion and capillary forces between the protrusions and the wafer under lithography conditions (especially EUV lithography conditions). Due to the lower friction, the forces on the wafer are smaller, and the in-plane deformation of the wafer is less. If the forces are too large, the wafer may become too deformed to be corrected, and therefore the wafer cannot be used. The protrusions may contain diamond-like carbon (DLC). Depending on the relative humidity to which the DLC is exposed, it will have a greater or lesser degree of hydrogenation. The coefficient of friction is inversely related to the degree of hydrogenation. Therefore, a hydrogen-free DLC surface has a higher coefficient of friction than a hydrogenated DLC surface, which subsequently has an even higher coefficient of friction than a highly hydrogenated DLC surface. The hydrogenated layer is typically very thin because it comprises a single hydrogen layer on the surface of a carbon lattice. In use, this hydrogenation can be abrasive or oxidized, resulting in a surface with a higher coefficient of friction, subsequently leading to greater wafer deformation and increased wear, thus reducing wafer clamping performance. The increased wear rate can also lead to greater adhesion between components. The first-state device of the present invention is configured to recalibrate the components of the lithography apparatus. By changing one or more of the following: the ratio of hydrogen ions to hydrogen radicals in the hydrogen plasma, changing the distance between the housing and the calibrated components, and the energy of the plasma, it is possible to carefully control the hydrogenation and / or oxidation / reduction of the component surface. Previously, hydrogen plasma was only used to remove materials such as carbon from surfaces, and therefore the advantages of adjusting conditions were not realized, making it possible to passivate the surface by providing a hydrogen layer. If the same conditions used for cleaning surfaces are applied to surfaces containing carbon-based protrusions, this will also remove the protrusions, which is undesirable. The energy of the plasma can be controlled by providing pulsed plasma (also known as modulated power plasma). Such pulsed plasmas have a higher average charged particle density at the same average power, which leads to damage to the underlying substrate. This can be attributed to the lower electron temperature during the off-time or lower power phase. In this way, pulsed or modulated plasmas are particularly well-suited for processing delicate surfaces by generating a high flux (average) of low-energy ions and a high flux of radicals. This pulsed or modulated plasma can be used to condition or clean sensors, such as dose / energy sensors, alignment sensors, and wavefront sensors, as well as other sensors in lithography apparatus that require cleaning or conditioning. Preferably, the apparatus is configured to include a vacuum or near-vacuum. Preferably, the apparatus is configured to have a substantially anhydrous environment therein.

[0006] The ratio of hydrogen ions to hydrogen radicals can vary due to their different reactivity. Hydrogen radicals are less reactive and therefore etch more slowly. Therefore, hydrogen radicals do not etch along the stable planes of the DLC. Hydrogen ions are more reactive and can etch the more stable facets of the DLC. Thus, hydrogen radicals reduce the height of the bumps and increase surface roughness, while hydrogen ions also reduce the height of the bumps but reduce roughness. During cleaning operations, rapid removal of contaminants is required, thus increasing the ratio of hydrogen ions to hydrogen radicals, but this is not necessary for surface readjustment and providing a passivated surface.

[0007] The surface can be readjusted by hydrogen passivation, and the control can also be achieved by adjusting the distance between the housing and the adjusted components, as well as by adjusting the plasma energy. Furthermore, when used for cleaning, parameters are selected to provide the fastest cleaning rate, and there is no need to change the distance between the cleaning device and the contaminant or adjust the plasma energy. The relatively high plasma energy allows for rapid cleaning, and the plasma is brought close to the contaminant again for rapid cleaning.

[0008] The device can be configured to provide energy to the hydrogen plasma at a range of approximately 2 eV to approximately 40 eV, approximately 4 eV to approximately 10 eV, and preferably approximately 4 eV to approximately 6 eV. This energy is lower than that used for contaminant removal. If the energy is higher than this, the incoming hydrogen plasma has sufficient energy to remove sputtered carbon from the surface, which would lead to increased wear and is undesirable when attempting to provide a passivation layer with a low coefficient of friction. In addition, sputtering can produce a surface with an undefined roughness, and hydrogen does not promote the hydrogenation of the surface and the corresponding reduction in the coefficient of friction. Furthermore, there is a risk that high-energy plasma may overheat the surface and damage it. Therefore, pulsed or modulated power plasmas can be provided.

[0009] The device may include an electrical bias unit configured to provide a potential difference between the housing and the component to control the energy supplied to the hydrogen plasma to the component. In the case where the component is a wafer stage, the wafer stage includes so-called Manhattan nodes electrically connected to ground. By applying a potential difference between the component and the hydrogen plasma housing, it is possible to tune the energy of the ions within the plasma and thereby control the passivation of the component's surface. Additionally, this allows for selective etching of plasma molecules, particularly in cases where oxygen or water is included to accelerate conditioning, and the type of ions (positive or negative) can be selected. For example, in the case of water, it is possible to select whether they are OH- ions or H+ ions impacting the surface. Furthermore, efficiency can be increased because the charge will attract ions toward nodes representing approximately 1% of the total surface area. By providing an electrical bias, a larger proportion of the ions are specifically attracted to the nodes, making conditioning or readjustment faster.

[0010] The device may include a controller for controlling the potential difference between the housing and the regulated components.

[0011] The housing may include one or more gas inlets. These gas inlets may be configured to supply hydrogen and / or oxygen to the housing. The hydrogen plasma may be formed from hydrogen. The gas may or may not contain a small amount of oxygen supplied. The amount of oxygen may be less than about 5 vol%, less than about 4 vol%, less than about 3 vol%, less than about 2 vol%, or less than about 1 vol%. The presence of oxygen will accelerate conditioning because the graphitized carbon (relative to the DLC of the protrusion) can be removed. Controlling the amount of oxygen to maintain a certain level ensures that the gas remains a reducing gas, allowing the surface to be passivated by the hydrogenated layer. If too much oxygen is present, the surface may oxidize, which will increase the coefficient of friction of the surface.

[0012] The apparatus may include a positioning device configured to position the housing to provide hydrogen plasma to the conditioned component. The positioning device may be configured to allow movement of the hydrogen plasma housing relative to the conditioned component. In this manner, the entire surface of the conditioned component can be exposed to and passivated by the hydrogen plasma. The positioning device may be configured to position the housing within approximately 1 mm to approximately 20 mm of the surface of the conditioned component. By adjusting the distance between the hydrogen plasma housing and the surface of the conditioned component, it is possible to control the degree of hydrogenation and thus the passivation of the surface.

[0013] The device can be configured to include hydrogen at pressures of about 1 Pa to about 40 Pa, preferably about 2 Pa to about 30 Pa.

[0014] The hydrogen plasma generator can be a radio frequency plasma generator.

[0015] The device may include one or more controllers for adjusting the pressure and / or composition of the gas within the device. By adjusting the pressure and / or composition of the gas within the device, it is possible to control the passivation of the surface of the regulated component.

[0016] The component may be a wafer stage. As described, the wafer stage includes a plurality of protrusions containing diamond-like carbon (DLC), but may have a microcrystalline or nanocrystalline diamond coating. The surfaces requiring DLC ​​or microcrystalline or nanocrystalline diamond coatings are passivated by the presence of hydrogen, which results in a lower coefficient of friction between the protrusions and the wafer positioned on the wafer stage.

[0017] According to a second aspect of the present invention, a method for adjusting the surface of a component of a lithography device is provided, the method comprising: i) providing a plasma housing configured to contain a plasma; ii) providing a plasma in the plasma housing; iii) exposing the surface of the component of the lithography device to the plasma; wherein one or more of the following are controlled to control the adjustment of the component: the ratio of hydrogen ions to hydrogen radicals in the plasma, the distance between the plasma housing and the component, and the energy of the plasma.

[0018] By controlling the ratio of hydrogen ions to hydrogen radicals in the hydrogen plasma, the distance between the hydrogen plasma casing and the surface of the component, and / or the energy of the plasma, it is possible to adjust the surface of the lithography device components. Adjustment can be for surface passivation, resulting in a reduced coefficient of friction. In embodiments, hydrogen gas at a pressure of 1 Pa to 40 Pa may be present. Preferably, in the presence of a gas other than hydrogen, it is a rare gas or oxygen. Adjustment can also be for surface cleaning, preferably via pulsed or modulated power plasma.

[0019] The hydrogen plasma may have an energy of about 2 eV to about 40 eV, about 4 eV to about 10 eV, and preferably about 4 eV to about 6 eV. By controlling the energy of the hydrogen plasma, the method can be adjusted to provide surface passivation without sputtering atoms from the surface.

[0020] The method may include providing an electrical bias voltage between the hydrogen plasma housing and the surface of the component, and controlling the magnitude of the bias voltage to control the energy of the plasma. The magnitude of the bias voltage can be adjusted to adjust the energy of the hydrogen ions within the plasma. This can be used to control the passivation of the component's surface.

[0021] The method may include moving the plasma housing relative to the surface of the component. Thus, the plasma housing may be scanned across the surface of the adjusted component, making the entire surface adjustable.

[0022] The method may include providing about 0.1 vol% to about 5 vol% oxygen in the plasma, preferably about 1 vol% to about 3 vol% oxygen in the plasma, or most preferably about 2 vol% oxygen in the plasma.

[0023] Providing oxygen allows for the removal of contaminants from the surface, allowing passivation to occur more rapidly. A reduced amount of oxygen can be provided to hydrogenate the surface of the component.

[0024] The method may include controlling a positioning device to position the plasma housing such that the surface of the component is exposed to the plasma. The method may include positioning the plasma housing within about 1 mm to about 20 mm of the surface of the component.

[0025] The method may include adjusting the pressure and / or power of the plasma to change the relative amounts of hydrogen ions and hydrogen free radicals in the plasma.

[0026] The method may include exposing the surface of the component to plasma for less than 15 minutes, less than 10 minutes, less than 5 minutes, less than 3 minutes, less than 120 seconds, less than 90 seconds, or less than 80 seconds. The method may include exposing the surface of the component to plasma for about 1 second to about 75 seconds, preferably about 30 seconds to about 60 seconds.

[0027] Since the surface needs to be passivated rather than the material needs to be removed from the surface, the time the surface is exposed to the plasma needs to be limited. The hydrogen passivation layer is only about one atom thick, so it does not require the surface to be exposed to hydrogen plasma for a long time.

[0028] According to a third aspect of the present invention, a lithography apparatus comprising the means of the first, sixth, or seventh aspect of the present invention is provided. Therefore, the means of the first aspect of the present invention may be included in the lithography apparatus in some embodiments, rather than as a separate unit.

[0029] According to the fourth aspect of the present invention, the use of the apparatus according to the first, third, sixth or seventh aspect of the present invention, or the use of the method according to the second or fifth aspect of the present invention in a lithography apparatus or method is provided.

[0030] According to a fifth aspect of the present invention, a method for processing a wafer abutment or wafer is provided, the method comprising providing one or more chemical substances at the wafer back interface of the wafer abutment, wherein the one or more chemical substances are selected to: i) have an adsorption time longer than that of H2 or F2; ii) form a chemical bond with C in a carbon coating that is weaker than an equivalent C-C bond in the carbon coating; or iii) avoid forming a chemical bond at the wafer back interface of the wafer abutment.

[0031] Degradation of wafer abutment flatness and wafer load grating (WLG) drift both contribute to overlay errors. On the one hand, the wafer abutment coating can oxidize and wear, leading to non-uniform flatness degradation, which in turn causes localized angle focusing and overlay problems. On the other hand, during wafer loading on the wafer abutment, the wafer contacts at some points, which can introduce a total error in the range of 1 nm to 5 nm. Such errors can be observed to drift over time. The wafer abutment may include a carbon coating such as diamond-like carbon to reduce such degradation. Even so, covalent bonds can form between the silicon oxide of the wafer and the carbon or chromium oxide of the wafer abutment. The repeated formation and breaking of such covalent bonds leads to increased friction, which exacerbates these problems. In addition, since C-C bonds are weaker than Si-O or OC bonds, carbon atoms will tend to migrate from the wafer abutment to the wafer over time, causing wear of the protective layer on the wafer abutment. According to the present invention, the direct formation of covalent bonds can be prevented by providing additional chemical or molecular substances, which reduce the direct interaction between the surfaces of the wafer and the wafer abutment, thereby leading to improved WLG and reduced wear. In this way, by providing substances that adsorb onto the surfaces of the wafer and / or wafer abutment for a longer period than hydrogen or fluorine, it is possible to maintain a passivation layer between the surfaces. Furthermore, providing substances with a lower activation barrier and weaker bonds than the C / C bonds of a carbon coating applied to the wafer abutment allows the C / C bonds to remain intact, even though other temporarily formed bonds break first. Additionally, molecules that do not bond on the two surfaces to form bridges between them can be provided, such as molecules with only one functional group (e.g., monohydric alcohols or monoacids), so that they do not form bridging bonds between the surfaces.

[0032] Chemical substances can be provided on the surface of the wafer stage. Although the chemical substances can also be provided on the bottom surface of the wafer supported by the wafer stage, this would require each wafer to be processed to include such additional chemical substances; however, if the chemical substances are provided on the wafer stage, no necessary changes to the wafer are required. Of course, it should be understood that the chemical substances can be coated on any one or two surfaces that are in contact with each other.

[0033] The method may include providing a chemical substance containing hydrogen atoms, which may form hydrogen bonds with the back side of the wafer or the wafer, or supplying hydrogen atoms to the back side of the wafer or the wafer.

[0034] Hydrogen atoms can be supplied to the silicon oxide surface and prevent the formation of bonds between oxygen atoms and carbon layers.

[0035] The chemical substance may include a hydroxide moiety. The hydroxide moiety is able to supply its protons to prevent the formation of covalent bonds between the wafer abutment and the wafer.

[0036] The chemical substance may include a linker group configured to provide separation between the wafer abutment and the back surface of the wafer. The linker group may include a hydrocarbon chain. By providing a linker, the separation between the wafer abutment and the wafer surface is increased, resulting in less interaction between the surfaces and thus a lower likelihood of forming unwanted covalent bonds.

[0037] A chemical substance may include one or more electron-withdrawing groups to lower the pKa of the substance. By lowering the pKa of the chemical substance, it becomes more acidic and the associated acidic hydrogen atoms are more readily exchanged. Suitable electron-withdrawing groups include halogens such as chlorine.

[0038] The chemical substance may be chlorine. Chlorine may be activated as required by the breaking of hemolyzed bonds during UV irradiation. In this way, chlorine can be used instead of HF for surface passivation.

[0039] The chemical substance may be a base. The chemical substance may be an amine. The chemical substance may be methylamine. The inclusion of this base prevents hydrogen in SiOH from transferring to the diamond (DLC) substrate present on the wafer stage. In addition, if the non-reactive substance is opposite to the base (such as methyl), the silicon oxide and carbon surfaces interact only minimally.

[0040] According to a sixth aspect of the present invention, a wafer stage for a lithography apparatus is provided, wherein the wafer stage comprises one or more chemical substances selected to: i) have an adsorption time longer than that of H2 or F2; ii) form a chemical bond with C in a carbon coating that is weaker than an equivalent C-C bond in the carbon coating; or iii) avoid forming a chemical bond at the back surface interface of the wafer stage. Similarly, according to a seventh aspect of the present invention, a wafer for a lithography apparatus is provided, wherein the wafer comprises one or more chemical substances selected to: i) have an adsorption time longer than that of H2 or F2; ii) form a chemical bond with C in a carbon coating that is weaker than an equivalent C-C bond in the carbon coating; or iii) avoid forming a chemical bond at the back surface interface of the wafer stage.

[0041] It should be understood that the features described in the sixth and seventh embodiments of the present invention also apply to each of them.

[0042] The wafer or wafer abutment may include a chemical substance having hydrogen atoms that can form hydrogen bonds with the back side of the wafer or wafer abutment, or supply hydrogen atoms to the back side of the wafer or wafer abutment. The chemical substance may include a hydroxide portion.

[0043] The chemical substance may include a linker group configured to provide separation between or between wafer abutments or wafer backsides, wherein the linker group comprises a hydrocarbon chain, and wherein the chemical substance is derived from methanol. Methanol is suitable because it includes proton-donating hydroxide groups and also has a low boiling point, allowing it to be readily incorporated into the gas stream without requiring high temperatures.

[0044] Chemical substances may include one or more electron-withdrawing groups selected to reduce the pKa of the substance. Such electron-withdrawing groups include halogens. A lower pKa allows for easier release of protons, which leads to deactivation of the DLC and also causes surface separation.

[0045] The chemical substance may be chlorine. Chlorine can be activated by uniform fracture caused by UV light irradiation.

[0046] The chemical substance may be an alkali. The chemical substance may be an amine. The chemical substance may be methylamine. The alkali allows the protons associated with silicon oxide to remain associated with it, and the methyl group provides some separation between the surfaces. In the presence of water, the DLC surface will be passivated and the silicon oxide surface will also be passivated. Due to the less interaction between the passivated surfaces, there is less wear on the surfaces.

[0047] It should be understood that the features described in any variant of the present invention can be combined with features of any other variant of the present invention, wherein such features are incompatible with each other. This covers all combinations of each variant of the present invention.

Implementation Method

[0049] Figure 1 illustrates a lithography system including a radiation source SO and a lithography device LA. The radiation source SO is configured to generate an EUV radiation beam B and supply the EUV radiation beam B to the lithography device LA. The lithography device LA includes an illumination system IL, a support structure MT configured to support a patterned device MA (e.g., a photomask), a projection system PS, and a substrate stage WT configured to support a substrate W. The substrate stage WT (also called a wafer stage) includes a plurality of protrusions configured to support the substrate W. The protrusions may contain diamond-like carbon (DLC).

[0050] The illumination system IL is configured to adjust the EUV radiation beam B before it is incident on the patterned device MA. Additionally, the illumination system IL may include a faceted field mirror device 10 and a faceted pupil mirror device 11. Together, the faceted field mirror device 10 and the faceted pupil mirror device 11 provide the EUV radiation beam B with the desired cross-sectional shape and intensity distribution. As a supplement to or alternative to the faceted field mirror device 10 and the faceted pupil mirror device 11, the illumination system IL may also include other mirrors or devices.

[0051] After such adjustment, 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 may 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 may apply a reduction factor to the patterned EUV radiation beam B', thus forming an image with features smaller than the corresponding features on the patterning device MA. For example, a reduction factor of 4 or 8 may be applied. Although the projection system PS is illustrated in FIG. 1 as having only two mirrors 13, 14, the projection system PS may include a different number of mirrors (e.g., six or eight mirrors).

[0052] The substrate W may include a previously formed pattern. In this 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.

[0053] A relative vacuum may be provided in the radiation source SO, in the lighting system IL and / or in the projection system PS, that is, a small amount of gas (e.g., hydrogen) at a pressure sufficiently lower than atmospheric pressure.

[0054] The radiation source SO shown in Figure 1 belongs to the type that can be called, for example, laser-generated plasma (LPP) source. A laser system 1, including, for example, a CO2 laser, can be configured to deposit energy via a laser beam 2 onto a fuel, such as tin (Sn), supplied from, for example, a fuel emitter 3. Although tin is mentioned in the following description, any suitable fuel can be used. The fuel can be, for example, in liquid form and can be, for example, a metal or alloy. The fuel emitter 3 can include a nozzle configured to guide, for example, tin in droplet form along a trajectory toward the plasma formation region 4. The laser beam 2 is incident on the tin at the plasma formation region 4. The deposition of laser energy into the tin generates tin plasma 7 at the plasma formation region 4. Radiation, including EUV radiation, is emitted from the plasma 7 during the de-excitation and recombination of electrons and ions in the plasma.

[0055] EUV radiation from the plasma is collected and focused by collector 5. Collector 5 includes, for example, a near-normal incident radiation collector 5 (sometimes more commonly referred to as a normal incident radiation collector). Collector 5 may have a multi-layered mirror structure configured to reflect EUV radiation (e.g., EUV radiation with a desired wavelength such as 13.5 nm). Collector 5 may have an ellipsoidal configuration with two foci. The first of the foci may be located at the plasma forming region 4, and the second of the foci may be located at the intermediate focal point 6, as discussed below.

[0056] The laser system 1 may be spatially separated from the radiation source SO. In this case, the laser beam 2 may be delivered from the laser system 1 to the radiation source SO via a beam delivery system (not shown), which includes, for example, suitable guide mirrors and / or beam expanders, and / or other optical components. The laser system 1, the radiation source SO, and the beam delivery system may be considered together as a radiation system.

[0057] The radiation reflected by collector 5 forms an EUV radiation beam B. The EUV radiation beam B is focused at the intermediate focal point 6 to form an image at the intermediate focal point 6 of the plasma present in the plasma forming region 4. The image at the intermediate focal point 6 serves as a virtual radiation source for the illumination system IL. The radiation source SO is configured such that the intermediate focal point 6 is located at or near the opening 8 in the enclosure structure 9 of the radiation source SO.

[0058] Although Figure 1 depicts the radiation source SO as a laser-generated plasma (LPP) source, any suitable source such as a discharge-generated plasma (DPP) source or a free electron laser (FEL) can be used to generate EUV radiation.

[0059] Figure 2 is a schematic depiction of an apparatus 15 for adjusting components of a lithography device, and the apparatus 15 is depicted as an adjusted component with reference to a wafer stage 16 (also referred to as a substrate stage WT). The wafer stage 16 includes a plurality of protrusions 17 comprising diamond-like carbon. The apparatus 15 includes a housing 18 configured to contain hydrogen plasma. The housing 18 may be cup-shaped and have at least one open face facing the wafer stage 16. In operation, the hydrogen plasma housing 18 contains hydrogen plasma 19. The apparatus may include gas inlets 21, 22 configured to supply hydrogen and, if applicable, oxygen to the hydrogen plasma housing. The apparatus 15 also includes a positioning device that adjusts the distance between the plasma housing 18 and the surface of the wafer stage 16, and also moves the housing 18 relative to the surface of the wafer stage 16 such that the protrusions 17 are exposed to and passivated by the hydrogen plasma 19. Electrical connection 23 can be disposed between the wafer stage 16 and the housing to provide and control electrical bias voltage to adjust the energy of hydrogen ions in the plasma 19.

[0060] In use, a wafer stage 16 comprising a plurality of protrusions 17 comprising diamond-like carbon is provided. A housing 18 is disposed adjacent to the wafer stage 16. Hydrogen and, if applicable, oxygen are supplied to the housing 18, which is then converted into plasma. A positioning device 20 is controlled such that the plasma 19 within the housing 18 interacts with the protrusions 17 and passivates the surface of the protrusions 17. An electrical bias voltage between the wafer stage 16 and the housing 18 is controlled to control the energy of hydrogen ions within the hydrogen plasma 19, thereby controlling the degree of passivation of the protrusions 17. The housing 18 can be scanned across the surface of the wafer stage 16 to ensure that each protrusion 17 is exposed to the hydrogen plasma 19.

[0061] Where the context permits, embodiments of the present invention may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the present invention may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by one or more processors. Machine-readable media may include any means for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, machine-readable media may include read-only memory (ROM); random access memory (RAM); magnetic storage media; optical storage media; flash memory devices; electrical, optical, acoustic, or other formed propagation signals (e.g., carrier waves, infrared signals, digital signals, etc.); and others. Furthermore, firmware, software, conventions, and instructions may be described herein as performing certain actions. However, it should be understood that such descriptions are for convenience only, and such actions are actually caused by a computing device, processor, controller, or other device executing firmware, software, conventions, instructions, etc., and in performing such actions, enable actuators or other devices to interact with the physical world.

[0062] Although specific embodiments of the invention have been described above, it should be understood that the invention may be practiced in other ways different from those described. The above description is intended to be illustrative and not restrictive. Therefore, it will be apparent to those skilled in the art that modifications can be made to the invention as described without departing from the scope of the claims set forth below. Examples

[0063] To demonstrate the effectiveness of the present invention, a sample of diamond-like carbon was obtained, and the contact angle of the sample was measured at different locations. Subsequently, the sample was adjusted according to the present invention, and the contact angle was again measured at various different locations. The experimental results are provided in Table 1 below. Table 1 Before processing After processing sample Contact angle (˚) sample Contact angle (˚) 1 50 1 76 2 49 2 73 3 52 3 76 4 51 4 76 5 47 5 77 Furthermore, Table 2 provides XPS results for three DLC samples with different corrosion levels treated with the same hydrogen plasma treatment according to the present invention. The plasma results are averaged at three locations. Table 2 sample O2 at t0 O2 after corrosion O2 after plasma 1 11.6% No data available 6.7 ± 0.1% 2 11.0% 14.5% 5.6 ± 0.1% 3 11.7% 20.4% 7.4 ± 0.5% As can be seen from Table 2, the amount of oxygen present is significantly reduced after plasma treatment.

[0064] As can be seen from Table 1, the contact angle was approximately 50˚ before passivation according to the present invention, but approximately 75˚ after treatment. This indicates that the hydrophobicity of hydrogen-passivated DLC is improved compared to that of oxidized DLC. The improvement in hydrophobicity corresponds to a reduction in the coefficient of friction. Therefore, the apparatus of the present invention provides a way to passivate the surface of a wafer abutment containing protrusions, the protrusions comprising DLC ​​or microcrystalline or nanocrystalline diamond, which has the advantage of reducing stress within the wafer supported by the wafer abutment. The reduction in stress results in lower wafer deformation. It was not previously recognized that hydrogen passivation of the surface of a wafer abutment containing protrusions could result in reduced deformation of the wafer supported thereby. The present invention provides an apparatus and method for reducing stress on a wafer by hydrogen passivating the surface of a wafer abutment.

[0065] Clause 1. An apparatus for regulating an assembly of a lithography device, the apparatus comprising: a housing configured to contain a hydrogen plasma; a hydrogen plasma generator configured to supply the hydrogen plasma to the assembly; wherein the apparatus is configured to control at least one of the following: the ratio of hydrogen ions to hydrogen radicals in the hydrogen plasma, the distance between the housing and the regulated assembly, and the energy of the plasma. 2. The apparatus of Clause 1, wherein the apparatus is configured to supply the hydrogen plasma with an energy of about 2 eV to about 40 eV, about 4 eV to about 10 eV, preferably about 4 eV to about 6 eV, wherein the plasma is, where appropriate, a pulsed or modulated power plasma. 3. The apparatus of any of the preceding clauses, wherein the apparatus includes a bias unit configured to provide a potential difference between the housing and the assembly to control the energy of the hydrogen plasma supplied to the assembly. 4. The device of claim 3, wherein the device further comprises a controller for controlling the potential difference between the housing and the regulated component. 5. The device of any of the preceding claims, wherein the housing includes one or more gas inlets, wherein the one or more gas inlets are configured to supply hydrogen and / or oxygen to the housing. 6. The device of any of the preceding claims, wherein the device includes a positioning device configured to position the housing to supply hydrogen plasma to the regulated component, wherein the positioning device is configured to position the housing within about 1 mm to about 20 mm of the surface of the regulated component. 7. The device of any of the preceding claims, wherein the device is configured to include hydrogen at a pressure of about 1 Pa to about 40 Pa, preferably about 2 Pa to about 30 Pa. 8. The device of any of the preceding claims, wherein the hydrogen plasma generator is a radio frequency plasma generator. 9. The apparatus of any of the preceding claims, wherein the apparatus includes one or more controllers for adjusting the pressure and / or composition of the gas within the apparatus. 10. The apparatus of any of the preceding claims, wherein the component is a wafer stage. 11. A method of adjusting the surface of a component of a lithography apparatus, the method comprising: i) providing a plasma housing configured to contain a plasma; ii) providing a plasma in the plasma housing; iii) exposing the surface of the component of the lithography apparatus to the plasma; wherein one or more of the following are controlled to control the adjustment of the component: the ratio of hydrogen ions to hydrogen radicals in the plasma, the distance between the plasma housing and the surface of the component, and the energy of the plasma. 12. The method of claim 11, wherein the plasma has an energy of about 2 eV to about 40 eV, about 4 eV to about 10 eV, preferably about 4 eV to about 6 eV. 13. The method of clause 11 or 12, wherein the method includes providing an electrical bias voltage between the plasma housing and the surface of the component, and controlling the magnitude of the electrical bias voltage to control the energy of the plasma.14. The method of any one of claims 11 to 13, wherein the method includes moving the hydrogen plasma housing relative to the surface of the component. 15. The method of any one of claims 11 to 14, wherein the method includes providing about 0.1 vol% to about 5 vol% oxygen in the plasma, preferably about 1 vol% to about 3 vol% oxygen in the plasma, or most preferably about 2 vol% oxygen in the plasma. 16. The method of any one of claims 11 to 15, wherein the method includes controlling a positioning device to position the hydrogen plasma housing such that the surface of the component is exposed to the hydrogen plasma, wherein, where applicable, the method includes positioning the hydrogen plasma housing within about 1 mm to about 20 mm of the surface of the component. 17. The method of any one of claims 11 to 16, wherein the method includes adjusting the pressure and / or power of the plasma to change the relative amounts of hydrogen ions and hydrogen radicals in the plasma. 18. The method of any one of claims 11 to 17, wherein the method includes exposing the surface of the component to the plasma for less than 15 minutes, less than 10 minutes, less than 5 minutes, less than 3 minutes, less than 120 seconds, less than 90 seconds, or less than 80 seconds. 19. The method of any one of claims 11 to 18, wherein the method includes exposing the surface of the component to the plasma for about 1 second to about 75 seconds, preferably about 30 seconds to about 60 seconds. 20. A method for processing a wafer abutment or wafer, the method comprising providing one or more chemical substances at a wafer backside interface of the wafer abutment, wherein the one or more chemical substances are selected to: i) have an adsorption time longer than H2 or F2; ii) form a chemical bond with C in a carbon coating that is weaker than an equivalent C-C bond in the carbon coating; or iii) avoid forming a chemical bond at the wafer backside interface of the wafer abutment. 21. The method of claim 20, wherein the chemical substance is provided on a surface of the wafer abutment. 22. The method of claim 20 or 21, wherein the method includes providing a chemical substance comprising a hydrogen atom, the hydrogen atom being capable of forming a hydrogen bond with a back side of a wafer or a wafer, or supplying a hydrogen atom to a back side of a wafer or a wafer. 23. The method of any one of claims 20 to 22, wherein the chemical substance comprises a hydroxide portion. 24. The method of any one of claims 20 to 23, wherein the chemical substance comprises a separate linker group configured to provide a discrete linker group between the wafer stage and the back side of the wafer, wherein, where applicable, the linker group comprises a hydrocarbon chain. 25. The method of claim 24, wherein the chemical substance comprises one or more electron-withdrawing groups selected to reduce the pKa of the substance. 26. The method of any one of claims 20 to 22, wherein the chemical substance is chlorine. 27. The method of any one of claims 20 to 22, wherein the chemical substance is a base,, where applicable, an amine, and, where applicable, methylamine.28. A wafer stage for a lithography apparatus, wherein the wafer stage comprises one or more chemical substances selected to: i) have an adsorption time longer than that of H2 or F2; ii) form a chemical bond with C in a carbon coating that is weaker than an equivalent C-C bond in the carbon coating; or iii) avoid forming a chemical bond at the back surface interface of the wafer stage. 29. A wafer for a lithography apparatus, wherein the wafer comprises one or more chemical substances selected to: i) have an adsorption time longer than that of H2 or F2; ii) form a chemical bond with C in a carbon coating that is weaker than an equivalent C-C bond in the carbon coating; or iii) avoid forming a chemical bond at the back surface interface of the wafer stage. 30. A wafer or anode as described in clause 28 or 29, wherein the chemical substance comprises a hydrogen atom that can form a hydrogen bond with a back side of the wafer or the wafer anode, or supply a hydrogen atom to a back side of the wafer or the wafer anode. 31. A wafer or anode as described in any one of clauses 28 to 30, wherein the chemical substance comprises a hydroxide portion. 32. A wafer or anode as described in any one of clauses 28 to 31, wherein the chemical substance comprises a linker group configured to provide a separate linker group between the wafer or anode and a back side of the wafer or the wafer anode, wherein, where applicable, the linker group comprises a hydrocarbon chain, wherein, where applicable, the chemical substance is derived from methanol. 33. A wafer or anode as described in clause 32, wherein the chemical substance comprises one or more electron-withdrawing groups selected to reduce the pKa of the substance. 34. A wafer or anode as described in any one of clauses 28 or 29, wherein the chemical substance is chlorine. 35. A wafer stage or wafer as described in any one of claims 28 to 30, wherein the chemical substance is an alkali, an amine, or methylamine, as described in the case of the chemical substance. 36. A lithography apparatus comprising the apparatus as described in any one of claims 1 to 10 or 28 to 35. 37. Use of the apparatus as described in any one of claims 1 to 10 or 20, or the method as described in any one of claims 11 to 27, or the wafer or wafer stage as described in any one of claims 28 to 35, in a lithography apparatus or method. [Simplified Explanation of the Diagram]

[0048] Embodiments of the invention will now be described by way of example only with reference to the accompanying schematic drawings, in which: - FIG1 depicts a lithography system including a lithography device and a radiation source; and - FIG2 is a schematic depiction of an apparatus according to one embodiment of the invention.

Claims

1. An apparatus for adjusting a component of a lithography device, the apparatus comprising: A housing configured to contain a hydrogen plasma; a hydrogen plasma generator configured to supply the hydrogen plasma to the component; wherein the device is configured to control the passivation of the component by controlling at least one of the following: the ratio of hydrogen ions to hydrogen radicals in the hydrogen plasma, the distance between the housing and the regulated component, and the energy of the hydrogen plasma.

2. The apparatus of claim 1, wherein the apparatus is configured to provide an energy of about 2 eV to about 40 eV to a hydrogen plasma, wherein the hydrogen plasma is a pulsed or modulated power plasma, as appropriate.

3. The apparatus of claim 1 or 2, wherein the apparatus includes an electrical bias unit configured to provide a potential difference between the housing and the component to control the energy supplied to the hydrogen plasma of the component.

4. The apparatus of claim 3, wherein the apparatus further comprises a controller for controlling the potential difference between the housing and the regulated component.

5. The apparatus of claim 1 or 2, wherein the housing includes one or more gas inlets, wherein, whereby, the one or more gas inlets are configured to supply hydrogen and / or oxygen to the housing.

6. The apparatus of claim 1 or 2, wherein the apparatus includes a positioning device configured to position the housing to provide hydrogen plasma to the adjusted assembly, wherein the positioning device is configured to position the housing within about 1 mm to about 20 mm of one surface of the adjusted assembly.

7. The apparatus of claim 1 or 2, wherein the apparatus is configured to include hydrogen at a pressure of about 1 Pa to about 40 Pa.

8. The apparatus of claim 1 or 2, wherein the hydrogen plasma generator is a radio frequency plasma generator.

9. The apparatus of claim 1 or 2, wherein the apparatus includes one or more controllers for adjusting the pressure of a gas and / or a component within the apparatus.

10. The apparatus of claim 1 or 2, wherein the component is a wafer stage.

11. A method for adjusting the surface of a component of a lithography apparatus, the method comprising: i) Provide a hydrogen plasma housing configured to contain a hydrogen plasma; ii) The hydrogen plasma is provided in the hydrogen plasma housing; iii) Exposing the surface of the component of the lithography device to the hydrogen plasma; One or more of the following are controlled to control the passivation of the component: the ratio of hydrogen ions to hydrogen radicals in the plasma, the distance between the plasma housing and the surface of the component, and the energy of the plasma.

12. A lithography apparatus comprising the means of any one of claims 1 to 10.

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