Patterning device loading method

Abstract

A lithographic apparatus and method are provided for loading a patterning device onto a support structure in a patterning device environment of the lithographic apparatus, the method comprising using a handling apparatus to bring the patterning device and the support structure together, energizing clamps that secure the patterning device to the support structure, and subsequently releasing the handling apparatus and the patterning device, wherein a plasma is present between the handling apparatus and the patterning device while the handling apparatus and the patterning device are separated.

Description

[Technical Field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims priority to European Application No. 23157549.9, filed February 20, 2023, which is incorporated herein by reference in its entirety.

[0002] [Technical field] The present disclosure relates to a method for loading a patterning device onto a support structure in a patterning device environment of a lithographic apparatus. The method may be used in a lithographic apparatus. [Background technology]

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

[0004] To project a pattern onto a substrate, a lithographic apparatus may use electromagnetic radiation. The wavelength of this radiation determines the minimum size of features that can be formed on the substrate. Lithographic apparatuses that use extreme ultraviolet (EUV) radiation having a wavelength in the range of 4-20 nm (e.g., 6.7 nm or 13.5 nm) may be used to form smaller features on a substrate than lithographic apparatuses that use radiation having a deep ultraviolet (DUV) wavelength of, for example, 193 nm. Summary of the Invention [Problem to be solved by the invention]

[0005] A potential problem in EUV lithography systems is that electrical discharges can occur, which, when they occur, can cause damage within the lithography system, for example, the electrical discharges can damage the patterning device within the lithography system, which then has to be replaced, which involves significant downtime for the lithography system and significant costs.

[0006] WO2019197128A2 discloses an apparatus including an electrostatic clamp for clamping a component and a mechanism for generating free charges near the electrostatic clamp, the mechanism for generating free charges being configured to generate free charges near the electrostatic clamp during a transition from a first energized state of the electrostatic clamp to a second energized state of the electrostatic clamp.

[0007] US20230008474A1 discloses a method, device, and system for reducing the electric field at the clamp-reticle interface using an improved electrostatic clamp. Specifically, the electrostatic clamp includes a clamp body, an electrode layer disposed on a top surface of the clamp body, and a plurality of burls protruding from a bottom surface of the clamp body, wherein the electrode layer includes a plurality of cutouts at predetermined locations that vertically correspond to the locations of the plurality of burls on the bottom surface of the clamp body.

[0008] CN115524919A discloses a reticle pod, a pod, and a handling method. The reticle pod includes a base having a first surface and a cover having a second surface disposed on the base. An internal space is formed between the base and the cover. The internal space contains a reticle and an electrostatic discharge material layer disposed on the first surface. The electrostatic discharge material reduces electrostatic charges on the reticle.

[0009] It would be desirable to provide a method of loading a patterning device that overcomes or mitigates one or more problems associated with the prior art. [Means for solving the problem]

[0010] According to a first aspect of the present disclosure, there is provided a method for loading a patterning device onto a support structure in a patterning device environment of a lithographic apparatus, the method comprising using a handling apparatus to bring the patterning device and the support structure together, energizing a clamp that secures the patterning device to the support structure, and subsequently releasing the handling apparatus and the patterning device, wherein a plasma is present between the handling apparatus and the patterning device while the handling apparatus and the patterning device are separated.

[0011] Advantageously, the plasma reduces the risk of electrical discharge when the handling apparatus and the patterning device are separated.

[0012] The handling device may hold a protective cover. A plasma may be provided between the protective cover and the patterning device.

[0013] Moving the handling device and the patterning device apart may comprise driving the handling device away from the patterning device.

[0014] A plasma may be present between the handling device and the patterning device while the patterning device and the support structure are brought together.

[0015] Bringing the patterning device and the support structure together may comprise a handling device driving the patterning device towards the support structure.

[0016] A plasma may be present between the handling device and the patterning device before the handling device starts to drive the patterning device relative to the support structure.

[0017] While the handling device and the patterning device are brought together, a plasma may be present between the handling device and the patterning device which is fixed relative to the support structure.

[0018] A plasma may be present between the support structure and the patterning device while the handling device and the patterning device are spaced apart from the support structure, which may comprise driving the handling device and the patterning device away from the support structure and / or driving the support structure away from the handling device and the patterning device.

[0019] The plasma may be generated for a period of at least 0.1 seconds.

[0020] The plasma may be an EUV-induced plasma that is generated by directing a beam of EUV radiation into a patterning device environment.

[0021] The beam of EUV radiation may be incident on one or more masking blades.

[0022] One or more masking blades may be provided such that the one or more masking blades block the EUV radiation beam.

[0023] The plasma may be generated using an ionizer device.

[0024] According to a second aspect of the present invention, there is provided a lithographic apparatus comprising a support structure for supporting a patterning device, a handling apparatus for handling the patterning device, and a controller, the controller being configured to bring the patterning device and the support structure together, energize clamps that secure the patterning device to the support structure, and subsequently separate the handling apparatus and the patterning device, the controller being configured to provide a plasma between the handling apparatus and the patterning device while the handling apparatus and the patterning device are separated.

[0025] Advantageously, the plasma reduces the risk of electrical discharge when the handling apparatus and the patterning device are separated.

[0026] According to a third aspect of the present invention there is provided a lithography system comprising the lithography apparatus of the second aspect, further comprising a radiation source, wherein the controller is configured to provide the plasma by driving a masking blade to block the EUV radiation beam provided by the radiation source.

[0027] Features of different aspects of the present disclosure may be combined together. [Brief explanation of the drawings]

[0028] Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying schematic drawings in which: FIG. 1 illustrates a schematic representation of a lithography system in which a method according to an embodiment of the present disclosure may be performed. FIG. 2 illustrates a schematic diagram of a method for loading a patterning device according to one embodiment of the present disclosure. 3A-3F show the method of FIG. 2 in more detail and schematically. DETAILED DESCRIPTION OF THE INVENTION

[0029] 1 shows a lithography system comprising a radiation source SO and a lithography apparatus LA. The radiation source SO is configured to generate a beam of EUV radiation B and to provide the beam of EUV radiation B to the lithography apparatus LA. The lithography apparatus LA comprises 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 substrate table WT configured to support a substrate W.

[0030] The illumination system IL is configured to condition the EUV radiation beam B before it is incident on the patterning device MA. In addition, the illumination system IL may include a facetted field mirror device 10 and a facetted pupil mirror device 11. Together, the facetted field mirror device 10 and the facetted pupil mirror device 11 provide the EUV radiation beam B with a desired cross-sectional shape and a desired intensity distribution. The illumination system IL may include other mirrors or devices in addition to or instead of the facetted field mirror device 10 and the facetted pupil mirror device 11.

[0031] After being conditioned in this manner, the EUV radiation beam B interacts with the patterning device MA. As a result of this interaction, a patterned EUV radiation beam B' is produced. The projection system PS is configured to project the patterned EUV radiation beam B' onto the substrate W. To that end, the projection system PS may comprise a plurality of mirrors 13, 14 configured to project the patterned EUV radiation beam B' onto the substrate W held by a substrate table WT. The projection system PS may apply a reduction factor to the patterned EUV radiation beam B' to form an image having smaller features than 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).

[0032] The patterning device MA and other elements may be provided within a housing 24. The interior defined by the housing may be referred to as a patterning device environment 25. The housing 24 may be substantially closed except for an opening at a lower end of the housing. A masking blade 20 is provided within the patterning device environment 25. The masking blade 20 is used to selectively mask areas of the patterning device MA so that only desired portions of the patterning device receive EUV radiation at any given time.

[0033] During scanning exposure, the patterning device MA and support structure MT are moved in the y direction, and the substrate W and substrate table WT are moved in the opposite y direction (and vice versa), so that a band of EUV radiation passes over the patterning device MA and through an exposure field on the substrate W.

[0034] A patterning device handling apparatus 30 (which may also be referred to as a handling apparatus) is provided within the patterning device environment 25. The handling apparatus 30 is used to remove a patterning device MA from a support structure MT and replace the removed patterning device with a different patterning device. The handling apparatus 30 may place the removed patterning device MA in a patterning device storage apparatus 32 (which may also be referred to as a storage apparatus). The handling apparatus 30 may take a different patterning device MA from the storage apparatus 32. The handling apparatus 30 may drive this different patterning device MA so that it is held in contact with the support structure MT. The handling apparatus 30 may then move away from the patterning device MA before commencing lithographic exposure. While the handling apparatus is moving away from the patterning device, a plasma may be present between the handling apparatus 30 and the patterning device MA (as described further below).

[0035] A relative vacuum may be provided in the radiation source SO, the illumination system IL, and / or the projection system PS, i.e. a small amount of gas (e.g. hydrogen) at a pressure well below atmospheric pressure. The same is true for the patterning device environment 25, i.e. a gas at a pressure below atmospheric pressure is present in the patterning device environment 25. The gas may be, for example, hydrogen.

[0036] The radiation source SO shown in FIG. 1 is of a type that may be designated, for example, as a laser-produced plasma (LPP) source. A laser system 1, which may include, for example, a CO laser, is arranged to deposit energy via a laser beam 2 into a fuel, such as tin (Sn), provided from a fuel emitter 3. While the following description refers to tin, any suitable fuel may be used. The fuel may be, for example, in liquid form or may be, for example, a metal or alloy. The fuel emitter 3 may comprise, for example, a nozzle configured to direct the tin, in the form of droplets, along a trajectory towards a plasma formation region 4. The laser beam 2 is incident on the tin in the plasma formation region 4. The deposition of laser energy into the tin generates a tin plasma 7 in the plasma formation region 4. During de-excitation and recombination of electrons and ions of the plasma, radiation including EUV radiation is emitted from the plasma 7.

[0037] EUV radiation from the plasma is collected and focused by a collector 5. Collector 5 may, for example, comprise a near-normal incidence radiation collector 5 (often more commonly referred to as a normal incidence radiation collector). Collector 5 may have a multi-layer mirror structure arranged to reflect EUV radiation (e.g., EUV radiation having a desired wavelength, such as 13.5 nm). Collector 5 may have an elliptical configuration with two foci. The first focus may be at the plasma formation region 4 and the second focus may be at an intermediate focus 6, as described below.

[0038] The laser system 1 may be spatially separated from the radiation source SO. In this case, the laser beam 2 may be passed from the laser system 1 to the radiation source SO by a beam delivery system (not shown) comprising, for example, suitable directing mirrors and / or beam expanders and / or other optical elements. The laser system 1, the radiation source SO and the beam delivery system may together be referred to as a radiation system.

[0039] The radiation reflected by the collector 5 forms an EUV radiation beam B. The EUV radiation beam B is focused at an intermediate focus 6 in order to form an image at the intermediate focus 6 in the plasma present in the plasma formation region 4. The image at the intermediate focus 6 acts as a virtual radiation source for the illumination system IL. The radiation source SO is arranged such that the intermediate focus 6 is located at or near an opening 8 in a closure structure 9 of the radiation source SO.

[0040] The operation of the radiation source SO may be controlled by a controller CT.

[0041] Although Figure 1 depicts the radiation source SO as a laser-produced plasma (LPP) source, any suitable source may be used to produce EUV radiation, such as a discharge-produced plasma (DPP) source or a free-electron laser (FEL).

[0042] Figure 2 shows schematically parts of the lithographic apparatus LA in more detail. Figure 2 shows schematically the housing 24 of the patterning device environment 25, the support structure MT, the masking blade 20 and the handling device 30. Figure 2 also shows a patterning device storage device 32. In Figure 2, the handling device 30 is in the middle of unloading a patterning device MA1 from the support MT and loading a different patterning device MA2 onto the support structure MT.

[0043] The support structure MT is movable in the Y direction (i.e. the scanning direction of the lithographic apparatus LA). The support structure MT is moved in the Y direction so as to be positioned above the handling device 30. The support structure MT may be at one end of its range of movement in the Y direction.

[0044] The handling apparatus 30 comprises an arm 34 mounted on an actuator 36. The patterning device MA2 being manipulated by the handling apparatus 30 is held on a protective cover 38. The protective cover 38 is configured to reduce the risk of damage to the pattern on the patterning device and / or contamination to the lowest patterned surface of the patterning device MA2 when the patterning device is being manipulated or stored. The protective cover 38 may also protect a pellicle (if present) connected to the patterning device MA2. The lowest patterned surface of the patterning device MA2 may be spaced from the protective cover 38 so that it does not directly contact the protective cover and prevents damage to the pattern caused by the protective cover.

[0045] Actuator 36 is configured to drive arm 34 upward and downward, as indicated by double arrow 40. In addition, actuator 36 is configured to drive arm 34 into and out of patterning device storage apparatus 32 through opening 39. This may be achieved, for example, by a combination of rotating arm 34 and extending and retracting the arm in the Y direction. In other arrangements, arm 34 may move differently to drive a patterning device into and out of patterning device storage apparatus 32.

[0046] As shown in FIG. 2, patterning device MA1 and associated protective cover 38 are removed from support structure MT and placed in patterning device storage apparatus 32. A different patterning device MA2 and associated protective cover 38 are then removed from the patterning device storage apparatus by handling apparatus 30. The different patterning device MA2 may be referred to as the second patterning device MA2. In a next step, handling apparatus 30 drives the second patterning device MA2 upward until it contacts support structure MT. Support structure MT may then be driven downward to meet the second patterning device MA2. A clamp (not shown) forming part of support structure MT is energized to fix second patterning device MA2 relative to support structure MT. Subsequently, arm 34 and protective cover 38 are driven downward, away from second patterning device MA2, which remains fixed relative to support structure MT.

[0047] As shown in FIG. 2 , the masking blades 20 are actuated to a configuration that blocks the EUV radiation beam B. The masking blades 20 may comprise a pair of masking blades 20 a, b that are movable in the Y direction. This pair of masking blades 20 a, b is used during lithographic exposure to control the Y-direction size of the patterning device area illuminated by the EUV radiation beam B. The masking blades 20 may further comprise a pair of X-direction movable blades. Only one of the X-direction movable blades, 20 c, is shown in FIG. 2 . The X-direction masking blades may be used to control the X-direction size of the patterning device area illuminated by the EUV radiation beam during lithographic exposure. In this way, during lithographic exposure, the masking blades 20 form the periphery of the area through which the EUV radiation beam B passes before impinging on the patterning device MA.

[0048] In Figure 2, the masking blades 20 are arranged to block the EUV radiation beam B. The Y direction masking blades 20a, b are actuated to be positioned away from the EUV radiation beam B. One of the X direction masking blades 20c is actuated to extend over the entire area illuminated by the EUV radiation beam B (i.e. extend over the entire EUV radiation beam in the X direction). Thus, the EUV radiation beam B is blocked by the X direction masking blades. Other masking blade configurations that block the EUV radiation beam B may be used.

[0049] As further described above, hydrogen (or other gas) is provided in patterning device environment 25. The hydrogen gas may have a pressure lower than atmospheric pressure. EUV radiation beam B is incident on the hydrogen gas. EUV radiation beam B ionizes hydrogen molecules in the hydrogen gas to create a plasma, which may be referred to as an EUV-induced plasma. Additionally, EUV radiation beam B may cause photoemission of electrons from masking blade 20. The photoemitted electrons may form part of the EUV-induced plasma and may cause further ionization of the hydrogen gas, further contributing to the EUV-induced plasma.

[0050] The plasma induced by the EUV radiation disperses within the patterning device environment 25. Thus, the plasma exists between the support structure MT and the second patterning device MA2. This is indicated schematically by the shaded area 50. In reality, the plasma 50 exists elsewhere within the patterning device environment 25, but this is not shown for ease of illustration. The plasma 50 exists between the support structure MT and the second patterning device MA2 when the handling apparatus 30 drives the second patterning device toward the support structure. Similarly, after the clamps on the support structure MT are energized to secure the second patterning device MA2, the plasma exists between the protective cover 38 and the second patterning device as the protective cover is driven away from the second patterning device. Advantageously, the presence of the EUV-induced plasma during this loading procedure of the second patterning device MA2 onto the support structure MT neutralizes or substantially neutralizes any charges that may be present on the second patterning device MA2 and the protective cover 38. This reduces the risk of electrical discharges between the second patterning device MA2 and the protective cover 38 when the protective cover is being driven away from the second patterning device. Similarly, the risk of electrical discharges between the second patterning device MA2 and the support structure MT when the second patterning device MA2 is being moved towards the support structure MT is also reduced.

[0051] FIG. 3 illustrates schematically the loading of patterning device MA2 onto support structure MT as a series of steps 3A-3F, according to one embodiment of the present disclosure.

[0052] 3A, a plasma 50 is provided between the patterning device MA2 and the support structure MT. As previously mentioned, the plasma 50 is induced by EUV radiation incident on the masking blade 20 within the patterning device environment 25. For ease of illustration, the plasma 50 is shown schematically only between the patterning device MA2 and the support structure MT. However, the plasma 50 may be distributed throughout the patterning device environment 25, for example, to occupy the space between all components within the patterning device environment.

[0053] Support structure MT comprises a base 52 and a clamp 54. Clamp 54 may be, for example, an electrostatic clamp. Clamp 54 is provided with an array of burls 58. Patterning device MA2 is supported by protective cover 38. Protective cover 38 includes protrusions 56 on which patterning device MA2 rests. Protrusions 56 may be positioned so as not to contact the patterned area of ​​patterning device MA2. Although protective cover 38 is shown schematically as being smaller than patterning device MA2, in practice the protective cover may be larger than the patterning device.

[0054] In Figure 3A, protective cover 38 and patterning device MA2 are moved upwards towards support structure MT, which movement may be provided by handling apparatus 30 (not shown).

[0055] Furthermore, as described above, the EUV-induced plasma 50 between the patterning device MA2 and the support structure MT neutralizes the charge on the support structure MT and the patterning device MA2, which reduces the risk of discharge due to the potential difference that exists between the patterning device MA2 and the support structure MT.

[0056] In the absence of plasma 50, there is a risk of discharge. The handling apparatus 30 may carry some electrostatic charge and may transfer some electrostatic charge to the patterning device MA2. Additionally or alternatively, the patterning device MA2 may itself already carry some electrostatic charge (e.g., acquired during a previous use or previous operation of the patterning device). The electrostatic charge may result in discharge (in the absence of plasma). In general, the amount of charge carried by the patterning device MA2 when it is loaded against the support structure MT may be unknown. In some cases, the amount of charge may be sufficient to result in discharge, and in other cases, the amount of charge may be insufficient to result in discharge. The plasma 50 neutralizes the charge on the patterning device MA2. This means that the charge state of the patterning device MA2 is known (rather than unknown, as in prior art systems).

[0057] 3B, support structure MT is driven downward toward patterning device MA2. This movement of support structure MT may occur after upward movement of patterning device MA2 and protective cover 38 is completed. Alternatively, downward movement of support structure MT may occur simultaneously with (or before) movement of patterning device MA2 and protective cover 38. EUV-induced plasma 50 continues to exist between patterning device MA2 and clamp 54, continuing to reduce the risk of discharge.

[0058] Generally, an EUV-induced plasma may be present between the patterning device MA2 and the clamping support structure MT when the patterning device and support structure are brought together.

[0059] 3C, patterning device MA2 contacts clamp 54. Patterning device MA2 contacts the end faces of burls 58. There is space around the burls, and as a result, gaps 60 exist between patterning device MA2 and the body of clamp 54. EUV-induced plasma may be present in these gaps 60.

[0060] 3D, the electrostatic clamp 54 is energized. In the embodiment shown, the clamp includes two electrodes 62, 64 that are electrically isolated from one another. In the embodiment shown, a negative potential is applied to the first electrode 62 and a positive potential is applied to the second electrode 64. The negative potential applied to the first electrode 62 induces a positive charge on the surface of the patterning device MA2 facing the first electrode. The positive potential applied to the second electrode 64 induces a negative charge on the surface of the patterning device MA2 facing the second electrode. This provides an attractive electrostatic force that secures the patterning device MA2 to the clamp 54 and, therefore, to the support structure MT. In other embodiments, the electrostatic clamp may include a different number of electrodes (e.g., four electrodes).

[0061] Although not shown, EUV-induced plasma 50 may exist between protective cover 38 and patterning device MA2. EUV-induced plasma 50 may exist on the sides of protective cover 38 and patterning device MA and may connect conductive portions of protective cover 38 to conductive portions of the patterning device. This plasma-mediated connection may equalize the electrical potential between protective cover 38 and patterning device MA (i.e., so that there is no potential difference between the protective cover and the patterning device).

[0062] Referring to FIG. 3E , patterning device MA2 and protective cover 38 are separated. This may be achieved by driving support structure MT (and patterning device MA2) away from protective cover 38 and / or by driving the protective cover away from the support structure. In the embodiment shown, support structure MT is driven upward and away from the protective cover. This lifts patterning device MA2 away from protective cover 38. Separating patterning device MA2 and protective cover 38 could generate a discharge because there is capacitance between the capacitor effectively formed by protective cover 38 and patterning device MA2. The capacitance decreases as a function of the distance between protective cover 38 and patterning device MA2, resulting in an increase in the potential difference between them. An EUV-induced plasma 50 exists between patterning device MA2 and protective cover 38. The EUV-induced plasma 50 neutralizes the charge on patterning device MA2 and protective cover 38. This reduces the risk of a discharge occurring.

[0063] Generally, an EUV-induced plasma 50 exists between the patterning device MA2 and the clamping support structure MT when the patterning device and support structure are separated.

[0064] 3F, protective cover 38 is driven downward, away from patterning device MA2. EUV-induced plasma 50 remains between protective cover 38 and patterning device MA2, reducing the risk of discharge occurring. Without the EUV-induced plasma, the risk of discharge occurring increases further as the spacing between patterning device MA2 and protective cover 38 increases.

[0065] In a subsequent step (not shown), the protective cover 38 may be driven into the storage apparatus 32. The masking blade 20 may be driven into a configuration that allows a lithographic exposure using the patterning device MA2 to be performed.

[0066] In the embodiments of the present disclosure described above, the plasma that reduces the risk of discharge during reticle loading is an EUV-induced plasma. To generate the EUV-induced plasma during patterning device loading, the radiation source SO may be operated at normal power (i.e., the power used when exposing a substrate). The radiation source SO may also be operated at a lower power, but will generate less plasma.

[0067] In the embodiments of the present disclosure described above, plasma is present in the patterning device environment when the patterning device is loaded onto the support structure. In addition, plasma may be present in the patterning device environment when the patterning device is removed from the support structure (e.g., when the handling apparatus and patterning device are brought together or when the handling apparatus and patterning device are moved away from the support structure).

[0068] The radiation source SO may operate continuously to provide the EUV radiation beam B during unloading of the patterning device and during loading of a replacement patterning device. This continuously induces a plasma that neutralizes charge on components in the patterning device environment 25. Alternatively, the EUV radiation beam B may be used to generate a plasma at a point in the patterning device unloading and loading process where there is a risk of discharge. For example, the EUV radiation beam B may be provided until the spacing between the patterning device MA and the support structure MT falls below a spacing threshold. This is because, once the spacing falls below the threshold, the patterning device MA and the support structure MT have already been neutralized and the risk of discharge becomes negligible. Generally, the EUV radiation beam B may be discontinued when the risk of discharge becomes negligible.

[0069] It may be desirable to generate the EUV-induced plasma when the patterning device MA and the support structure MT are at a maximum distance from each other, because the maximum distance provides a larger volume for the EUV-induced plasma to enter. In addition, the capacitance established by the patterning device MA and the support structure MT is minimum (and the potential difference between the patterning device and the support structure is maximum).

[0070] During the patterning device load process, it may be desirable to generate the EUV-induced plasma for a period sufficient to neutralize the patterning device MA, which may be, for example, less than 1 second, for example, at least 0.1 seconds.

[0071] Although the plasma that reduces the risk of discharge during reticle loading has been described as an EUV-induced plasma, the plasma may be generated in other ways. For example, an ionizer device configured to ionize hydrogen gas (or other gas) in the patterning device environment may be provided. Using an EUV-induced plasma may be advantageous because it does not require providing additional equipment (e.g., an ionizer device).

[0072] In an embodiment, the protective cover may be omitted, in which case the patterning device may be handled directly by the handling device, or instead of a protective cover a different element may be provided between the patterning device and the handling device.

[0073] 1, the controller CT may be configured to control the operation of the radiation source SO. The controller CT may be configured to control the position of the masking blade 20 and the movement of the handling device 30 and the support structure MT. The controller CT may be configured to apply a method according to an embodiment of the present disclosure.

[0074] A method according to an embodiment of the present disclosure may be performed by a computing device. The device may include a central processing unit ("CPU") coupled to a memory. The methods described herein may be implemented in code (software) stored on a memory comprising one or more storage media and arranged for execution on a processor comprising one or more processing units. The storage media may be integrated into the CPU and / or may be separate from the CPU. The code, which may be referred to as instructions, is configured to be fetched from the memory and executed on the processor to perform operations in accordance with the embodiments discussed herein. Alternatively, it is not excluded that some or all of the functionality of the CPU may be implemented in dedicated hardware circuits or configurable hardware circuits such as FPGAs.

[0075] The computing device may comprise an input configured to allow a user to input data into the software program running on the CPU. The input device may comprise a mouse, keyboard, touch screen, microphone, etc. The computing device may further comprise an output device configured to output the results of the measurements to the user.

[0076] Although specific reference may 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 may have other applications, including the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads, etc.

[0077] Although specific reference may be made in this text to embodiments of the present disclosure in the context of a lithography apparatus, embodiments of the present disclosure may be used in other apparatus. Embodiments of the present disclosure may form part of a mask inspection apparatus, a metrology apparatus, or any apparatus that measures or processes objects such as wafers (or other substrates) or masks (or other patterning devices). These apparatus may be generally referred to as lithography tools. Such lithography tools may use vacuum or atmospheric (non-vacuum) conditions.

[0078] Although specific reference may be made to the use of embodiments of the present disclosure in the context of optical lithography, it will be understood that the present disclosure is not limited to optical lithography, but may also be used in other applications, such as imprint lithography, where the context permits.

[0079] Where the context permits, embodiments of the present disclosure may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the present disclosure may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a manner readable by an apparatus (e.g., a computing device). For example, a machine-readable medium may include read-only memory (ROM), random-access memory (RAM), magnetic storage media, optical storage media, flash memory devices, electrical, optical, acoustic, or other forms of transmission signals (e.g., carrier waves, infrared signals, digital signals, etc.), etc. Furthermore, firmware, software, routines, and instructions may be described herein as performing particular actions. However, it should be understood that such description is for convenience only, and that such actions may actually be caused by a computing device, processor, controller, or other device executing the firmware, software, routines, instructions, etc., causing actuators or other devices to interact with the physical world.

[0080] While specific embodiments of the present disclosure have been described above, it will be understood that the present disclosure may be practiced otherwise than as described. The foregoing description is intended to be illustrative and not limiting. Thus, it will be apparent to those skilled in the art that modifications may be made to the disclosure as described without departing from the scope of the claims set forth below.

Claims

1. 1. A method for loading a patterning device onto a support structure in a patterning device environment of a lithographic apparatus, comprising: using a handling apparatus to bring together the patterning device and the support structure; energizing clamps that secure the patterning device to the support structure; subsequently separating the handling device and the patterning device; Equipped with a plasma is present between the handling device and the patterning device while the handling device and the patterning device are separated; the handling device holds a protective cover; the plasma is provided between the protective cover and the patterning device. method.

2. The method of claim 1 , wherein moving the handling apparatus and the patterning device apart comprises driving the handling apparatus away from the patterning device.

3. The method of claim 1 or 2, wherein a plasma is present between the handling device and the patterning device while the patterning device and the support structure are brought together.

4. The method of claim 3 , wherein the plasma is generated when the patterning device and the support structure are at a maximum spacing from each other.

5. The method of claim 3 , wherein the plasma is provided until a spacing between the patterning device and the support structure falls below a spacing threshold.

6. The method of claim 3 , wherein bringing the patterning device and the support structure together comprises the handling device driving the patterning device towards the support structure.

7. The method of claim 1 , wherein a plasma is present between the handling device and the patterning device before the handling device starts to drive the patterning device relative to the support structure.

8. The method of claim 1 , wherein a plasma is present between the handling device and the patterning device fixed relative to the support structure while the handling device and the patterning device are brought together.

9. The method of claim 1 , wherein a plasma is present between the support structure and the patterning device while the handling apparatus and the patterning device are moved away from the support structure.

10. The method of any of claims 1 to 9, wherein the plasma is an EUV-induced plasma generated by directing a beam of EUV radiation into the patterning device environment.

11. The method of claim 10 , wherein the beam of EUV radiation is incident on one or more masking blades.

12. 12. The method of claim 11, wherein one or more masking blades are provided such that the one or more masking blades block the beam of EUV radiation.

13. The method of any of claims 1 to 12, wherein the plasma is generated using an ionizer device.

14. 1. A lithographic apparatus comprising: a support structure for supporting a patterning device; a handling device that holds a protective cover and the patterning device; and a controller, The controller bringing together the patterning device and the support structure; and energizing clamps that secure the patterning device to the support structure; subsequently separating the handling device and the patterning device; configured to run the controller is configured to provide a plasma between the protective cover and the patterning device while the handling device and the patterning device are spaced apart. Lithography equipment.

15. A lithographic apparatus comprising: further comprising a radiation source; the controller is configured to provide the plasma by driving a masking blade to block an EUV radiation beam provided by the radiation source. Lithography system.

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