Device for assembling a reticle assembly

Abstract

The present invention relates to an object handling device for handling roughly planar objects, the object handling device comprising: two support arms, at least one of the two support arms being movable roughly in a plane relative to the other support arm, so that the two support arms are operable to grasp and hold objects set in the plane; wherein each of the support arms comprises at least one support pad and at least one aligner, the support pad being configured to locally contact the surface of the object and apply a force roughly perpendicular to the plane to support the object, and the aligner being configured to locally contact the surface of the object and apply a force roughly in the plane to grasp the object.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to EP application 19159943.0 filed on February 28, 2019, EP application 19163828.7 filed on March 19, 2019, and EP application 19191214.6 filed on August 12, 2019, all of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to an apparatus and an associated method for assembling a reticle assembly of a lithographic apparatus, the reticle assembly comprising a pellicle assembly connected to the reticle. Background Art

[0004] A lithographic apparatus is a machine configured to apply a desired pattern to a substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). For example, a lithographic apparatus can project a pattern from a patterning device (e.g., a mask) onto a layer of radiation-sensitive material (resist) disposed on a substrate.

[0005] The wavelength of radiation used by a lithographic apparatus to project a pattern onto a substrate determines the minimum size of features that can be formed on that substrate. Lithographic apparatus using EUV radiation (electromagnetic radiation with a wavelength in the range of 4 to 20 nm) can be used to form smaller features on a substrate than conventional lithographic apparatus (which can use electromagnetic radiation with a wavelength of, for example, 193 nm).

[0006] A patterning device (e.g., a mask) used to impart a pattern to a radiation beam in a lithographic apparatus may form part of a mask assembly. The mask assembly may include a pellicle to protect the patterning device from particle contamination. The pellicle may be supported by a pellicle frame.

[0007] It may be desirable to provide an apparatus that obviates or mitigates one or more problems associated with the prior art. Summary of the Invention

[0008] According to a first aspect of the present invention, there is provided an object handling device for handling substantially planar objects, the object handling device comprising: two support arms, at least one of the two support arms being movable substantially in a plane relative to the other support arm, so that the two support arms are operable to clamp and hold an object disposed in the plane; wherein each of the support arms comprises at least one support pad and at least one aligner, the support pad being configured to locally contact the surface of the object and apply a force substantially perpendicular to the plane thereto to support the object, and the aligner being configured to locally contact the surface of the object and apply a force substantially in the plane thereto to align the object.

[0009] The object handling apparatus is advantageous because it reduces the amount of friction between the arm and the object. This, in turn, can reduce the amount of particulate debris that may be generated by such friction. The object can be a pellicle assembly or a patterning device. The object handling apparatus is particularly advantageous for use when handling pellicle assemblies or patterning devices, as it is particularly important that these objects remain clean and free of contaminants.

[0010] It will be appreciated that because each of the support pads and aligners only partially contacts the object, they only contact a relatively small portion of the object. Advantageously, this can reduce the risk of particulate contamination (compared to a support mechanism that contacts the entire periphery of the pellicle assembly or patterning device).

[0011] The aligner is arranged to ensure that when the object is clamped by the support arm, the object is in a known, fixed position relative to the object handling apparatus.

[0012] According to a second aspect of the present invention, there is provided an object handling device for handling substantially planar objects, the object handling device comprising: two support arms, at least one of the two support arms being movable substantially in a plane relative to the other support arm, so that the two support arms are operable to clamp and hold objects disposed in the plane; a support structure; and a damper assembly; wherein the two support arms are connected to the support structure via the damper assembly, and the damper assembly is configured to suppress movement of the object in a direction perpendicular to the plane of the object when the object is clamped by the support arms.

[0013] The object may be a pellicle assembly or a patterning device.The damper assembly may be configured to dampen movement of the object (eg, the pellicle assembly or the patterning device) in a direction in which the object (eg, the pellicle assembly or the patterning device) would typically be presented to the object handling apparatus.

[0014] The support structure may be a track. Advantageously, this arrangement allows the position of the pellicle assembly or patterning device to be moved along the track of the track while preventing damage to the pellicle assembly or patterning device (e.g., caused by dropping the pellicle assembly or patterning device).

[0015] According to a third aspect of the present invention, a pellicle frame attachment device is provided, comprising: a pellicle assembly handling device configured to handle a pellicle assembly; a pattern forming device handling device configured to handle a pattern forming device; and rails, wherein the pellicle assembly handling device comprises a support arm configured to clamp and hold the pellicle assembly, and the pattern forming device handling device comprises a support arm configured to clamp and hold the pattern forming device, and wherein the pellicle assembly handling device is supported by and movable relative to one of the rails, and wherein the pattern forming device handling device is supported by and movable relative to one of the rails.

[0016] In a lithographic apparatus, a mask assembly may be used. The mask assembly may include a patterning device (which imparts a desired pattern to a radiation beam during use) and a pellicle assembly (which prevents contaminant particles from reaching the patterning device). The pellicle assembly may include a coupling mechanism attached to a frame of the pellicle assembly. The pellicle assembly may be attached to the patterning device using studs via the coupling mechanism. A pellicle frame attachment device may be used to attach the pellicle assembly to the patterning device.

[0017] When securing the pellicle assembly to the patterning device (thereby forming a mask assembly), it is important that the engagement mechanism of the pellicle assembly and the studs of the patterning device are carefully handled and well aligned. The pellicle frame attachment device may include a handling device for the pellicle assembly and a handling device for the patterning device to accurately and carefully clamp, move, and place the pellicle assembly and the patterning device.

[0018] The pellicle assembly handling apparatus may include a portion that may be described as a pellicle assembly holder. The patterning device handling apparatus may include a portion that may be described as a patterning device holder. The holder may be movably attached to the rail. The holder may be operable to be manually moved along a track disposed within the rail. Advantageously, movably attaching the pellicle assembly holder and the patterning device holder to a common rail may allow for accurate and safe handling of the pellicle assembly and the patterning device.

[0019] The pellicle assembly disposal apparatus may comprise an object disposal apparatus according to the first aspect of the present invention.

[0020] The patterning device handling apparatus may comprise an object handling apparatus according to the first aspect of the invention.

[0021] The pellicle assembly disposal apparatus may comprise an object disposal apparatus according to the second aspect of the present invention.

[0022] The patterning device assembly handling apparatus may comprise an object handling apparatus according to the second aspect of the invention.

[0023] According to a fourth aspect of the present invention, there is provided a measuring system for measuring an object, comprising: a radiation source for generating an unpolarized radiation beam; a beam splitter; a quarter-wave plate; and an imaging sensor; wherein the radiation source is arranged so that a portion of the unpolarized radiation propagates through the beam splitter and the quarter-wave plate; and wherein the imaging sensor is arranged so that a reflected portion of the portion of the unpolarized radiation passes through the quarter-wave plate and the beam splitter before being incident on the imaging sensor.

[0024] The optical measurement system may be operable to measure the position of the pellicle frame.The optical measurement system may include a radiation source, a beam splitter, a quarter wave plate, and an imaging sensor.

[0025] The radiation source can emit unpolarized light. The unpolarized light can be split by a beam splitter. This can produce linearly polarized light. At least a portion of the linearly polarized light can then propagate through a quarter wave plate, thereby becoming circularly polarized. The pellicle assembly (including the pellicle and the pellicle frame) and the patterning device (such as a reticle) can be arranged so that the circularly polarized light is reflected from the patterning device after propagating through the pellicle and / or the pellicle frame. The reflected circularly polarized light can then propagate back through the quarter wave plate and the beam splitter and be incident on the imaging sensor. Measurements made by the imaging sensor can enable the position of the pellicle frame (and therefore the pellicle assembly) to be determined.

[0026] At least a portion of the circularly polarized beam generated by the quarter wave plate can be incident on a pattern forming device and reflected by the pattern forming device. The edges of the pellicle frame may obstruct the light reflected from the pattern forming device. At least a portion of the radiation reflected by the pattern forming device is incident on an imaging sensor and can have a measured spatial intensity (such as a measured image) at the imaging sensor that varies depending on the position of the edge of the pellicle frame. Specifically, the difference in the transmission level of light through the pellicle and the pellicle frame can give a spatial contrast in the intensity measurement. This spatial contrast can be particularly useful for measuring the position of the pellicle assembly and subsequently aligning the pellicle assembly.

[0027] As light propagates through the quarter-wave plate, the quarter-wave plate effects a phase shift (between the two orthogonal components of the electric field intensity) in the light reflected from the patterning device. This phase shift causes the light reflected from the patterning device to be transmitted through the beam splitter to a maximum extent. Maximum transmission of light through the beam splitter may result in a high signal in the intensity measurement performed by the imaging sensor. For example, the measurement performed by the imaging sensor may be affected by background light, which may reduce the contrast in the image representing the edges of the pellicle and the pellicle frame. However, this background radiation may be unpolarized, so that only a small portion (e.g., half) of this background radiation may reach the imaging sensor. In contrast, the signal radiation (i.e., the portion of the radiation reflected from the patterning device) is transmitted through the beam splitter to a maximum extent. Advantageously, maximum transmission of this signal light through the beam splitter may result in a high spatial contrast in the measurement performed by the imaging sensor. This may result in a high accuracy in the position measurement of the pellicle assembly.

[0028] According to a fifth aspect of the present invention, there is provided a measuring system for measuring the position of an object relative to a reference object, the object being provided with an object identification, and the reference object being provided with a window having a reference identification, the measuring system comprising: a radiation source for generating a radiation beam; and an imaging sensor; the radiation source being arranged so that the radiation beam is incident on the reference identification and the object identification at such an angle that a reflected diffraction order of the radiation is incident normally on the imaging sensor.

[0029] The optical measurement system may be operable to measure the position of an object relative to a reference object. The object may be a patterning device (such as a reticle). The object may be provided with an object identifier. The object identifier may include a diffraction grating. The object identifier may include an alignment mark. The reference object may be a window. The reference object may be provided with a reference identifier. The reference identifier may include a diffraction grating. The reference identifier may include an alignment mark. The optical measurement system may include a radiation source and an imaging sensor.

[0030] A radiation source can emit a beam. The beam can propagate toward an object and a reference object. A portion of the beam can be backscattered (e.g., reflected) from a reference marker. Another portion of the beam can be transmitted through the reference object. This portion of the beam can then be backscattered (e.g., reflected) from the object marker. Each of the object marker and the reference marker can be arranged to form a reflective diffraction grating. The portion of the beam backscattered from each of the object marker and the reference marker can form multiple diffraction orders. The first-order reflected beam can be incident on an imaging sensor. Therefore, the imaging sensor can be operable to measure a signal corresponding to the position of the object relative to the reference object. The zero-order reflected beam (corresponding to the standard reflection) may not be incident on the imaging sensor. The optical measurement system can be operable to measure the position of the object marker (fixed relative to the object) and the reference marker (fixed relative to the reference object). Therefore, the optical measurement system can be operable to measure the position of the object relative to the reference object. This can be used to align the object with the reference object. For example, the optical measurement system can be used to align the pattern forming device with another device.

[0031] Advantageously, measuring the position of the object marker and the reference marker by measuring the diffraction orders of light (as described above) and using the same measurement equipment (optical measurement system) can result in an accurate measurement of the position of the object relative to the reference object. This can result in a more accurate measurement of the object position than if the position of the object (such as a patterning device) were based on measuring the position of an edge of the object (such as an edge of the patterning device).

[0032] A pellicle frame attachment device includes the measuring system of the fourth aspect of the present invention or the measuring system of the fifth aspect of the present invention.

[0033] According to a sixth aspect of the present invention, a diaphragm frame attachment device is provided, comprising: a support structure configured to support a diaphragm assembly; and a linearly movable manipulator pin configured to move relative to the support structure to contact a distal end of a coupling arm of a coupling mechanism attached to a frame of the diaphragm assembly when supported by the support structure to elastically bend the coupling arm; wherein the manipulator pin extends in a direction substantially perpendicular to the coupling arm and is movable in the direction; and wherein a surface of the manipulator pin is a convex surface so that a contact surface area between the surface and the coupling arm is minimized.

[0034] It will be appreciated that when the manipulator pin moves and contacts a generally vertical engagement arm (e.g. a resilient cantilevered engagement arm), it can move the distal end of the engagement arm, thereby rotating the engagement arm. As the manipulator pin moves in a linear direction, the point of contact between the manipulator pin and the engagement arm will move along the surface of the engagement arm. By providing the manipulator pin with a convex curved surface, the surface area of contact between the manipulator pin and the engagement arm is minimized. This arrangement can ensure that sliding between the manipulator pin and the engagement arm is minimized. Advantageously, this can reduce the risk of generating particulate contamination (compared to the interface between the manipulator pin and the engagement mechanism where the components slide over each other).

[0035] The apparatus may further comprise an actuator operable to move the position of the support structure and a plurality of hook pins disposed on and protruding from the support table, wherein the plurality of hook pins are configured to releasably clamp the engagement mechanism to the support structure as appropriate during engagement or disengagement of the pellicle assembly and the pattern forming device, and wherein if movement of the support table is obstructed, either or both of the actuator or the plurality of detachable inserts on which the hook pins are provided are capable of being detached from the support table.

[0036] A hook pin can be used to keep the pellicle assembly fixed to the support structure during engagement or disengagement of the pellicle assembly and the pattern forming device. This allows movement of the support structure to cause corresponding movement of the pellicle assembly. However, the hook pin may not be able to disengage from the pellicle frame. The above-mentioned detachment mechanism provides a safety mechanism to detach the hook pin from the actuation mechanism when movement is impeded to prevent damage to the pellicle assembly. In some embodiments, the detachment mechanism can detach the support table from the actuator. In some embodiments, the detachment mechanism can be implemented by providing a hook pin on a detachable insert (which is detachably connected to the support structure).

[0037] According to a seventh aspect of the present invention, there is provided a stud attachment apparatus comprising: a support structure configured to hold a patterning device; and a stud manipulator configured to bring a stud into contact with the patterning device, wherein the stud manipulator is attached to an outer frame using a plurality of leaf springs.

[0038] The studs can be attached to the patterning device such that the pellicle assembly can be attached to the patterning device. The studs can be attached to the patterning device using a stud attachment device. The stud attachment device can include a stud manipulator that handles the studs. The stud manipulator can be attached to the outer frame. The attachment can include a plurality of leaf springs. The plurality of leaf springs allow some relative movement between the stud manipulator and the outer frame (e.g., when the base of the stud contacts the patterning device).

[0039] Each leaf spring is sized to allow for permissible movement of the stud manipulator (relative to the outer frame) in the direction in which the stud can be applied to the patterning device (e.g., the z-direction), while allowing negligible movement in other directions. Furthermore, by using multiple leaf springs rather than a single leaf spring, rotation of the stud manipulator (and therefore the stud) in the xz or yz planes is negligible. Advantageously, this can result in more controlled stud position and more accurate placement of the stud on the patterning device.

[0040] The stud handler may comprise a stud holder arranged to hold the stud under gravity or using a vacuum mechanism.

[0041] The stud manipulator may include a glue dispenser. The glue dispenser may be configured to dispense poly(methyl methacrylate)-based glue. As used herein, poly(methyl methacrylate)-based glue may be referred to as PMMA glue. The glue dispenser may be configured to provide PMMA glue as one or more components. The glue dispenser may be configured to provide at least one component of the PMMA glue to the surface of the stud. The glue dispenser may be configured to provide at least one component of the PMMA glue to the surface of the patterning device. The glue dispenser may be configured to provide at least one component of the PMMA glue to the surface of the stud and to provide at least one component of the PMMA glue to the surface of the patterning device. When the stud contacts the patterning device through the stud manipulator, the stud may be attached to the patterning device by the PMMA glue.

[0042] PMMA glue includes a thermoplastic resin formed by the polymerization of methyl methacrylate (MMA) monomer. PMMA glue is typically a resin formulation including MMA monomer and one or more other components (such as initiators, accelerators, cross-linking agents and other additives). It will be appreciated that, as used herein, providing a surface with PMMA glue may refer to providing the surface with one or more components (such as a resin component comprising an accelerator or initiator of PMMA glue) of PMMA glue. It will also be appreciated that, as used herein, contacting a surface with another surface may refer to indirectly contacting two surfaces with each other (such as via glue bonded to two surfaces).

[0043] For example, the processing of PMMA glue includes providing a first glue component including a mixture of MMA monomer and accelerator and a second glue component including a mixture of MMA monomer and initiator. Preferably, when the first glue component and the second glue component are combined, the initiator is provided in an amount suitable for the total amount of the first glue component and the second glue component. The application of the glue component is completed, for example, by applying the first glue component to the first substrate and applying the second glue component to the second substrate. For example, the first glue component including MMA monomer is applied to the surface of the pellicle frame, and the second glue component including initiator is applied to the surface of the pattern forming device to be bonded to the pellicle frame coated with the first glue component. Alternatively, the two glue components can be applied in opposite ways. When the two substrates are combined, curing will occur.

[0044] PMMA glue can be used to bond the surface of a first lithographic component to the surface of a second lithographic component. At least one of the first lithographic component and the second lithographic component can be a component of an EUV lithographic apparatus. For example, the first lithographic component is a pellicle, and the second lithographic component is a pellicle frame. In another example, the first lithographic component is a pellicle frame, and the second lithographic component is a patterning device. In yet another example, the first lithographic component is a first pellicle frame component, such as a first component of a pellicle frame engagement mechanism, and the second lithographic component is a second component of the pellicle frame engagement mechanism.

[0045] In an alternative method, the first component and the second component can be applied side by side to the same substrate, and then the second substrate can be applied thereon, so that the PMMA adhesive component is sandwiched between the two substrates. In the alternative method, when the first component and the second component are in full contact with each other due to being enclosed between the two surfaces, curing then occurs. Other alternative processing methods can also be applied.

[0046] The PMMA adhesive component can be applied as a layer, as a single continuous shape, or as discrete beads. The advantage of applying the adhesive as beads is that it provides less tension in the surfaces being glued, such as between a pellicle and a frame, or between a frame and a reticle surface. In this case, the beads act as an elastic spring between the two surfaces.

[0047] Preferably, the thickness of the layer or bead is less than 0.6 mm, more preferably less than 0.5 mm. This is to allow for optimal polymerisation as polymerisation starts on one side of the layer or bead and proceeds to the other side.

[0048] Beads herein refer to discrete portions of the glue component rather than a continuous layer, and can have any shape, such as spherical, hemispherical, or quasi-rectangular, depending on the wettability and viscosity of the PMMA resin.

[0049] The viscosity of the PMMA resin is preferably at least 8000 mPas, more preferably at least 10.000 mPas. The hardening of the PMMA glue can be accelerated chemically or by heating.

[0050] The glue or adhesive used to attach the pellicle to the pellicle frame or the pellicle frame to the reticle preferably has a lap shear strength of >5 MPa, more preferably >10 MPa, as tested according to standard ISO 4587 (OI3). The Young's modulus of the glue or adhesive used to attach the pellicle to the pellicle frame or the pellicle frame to the reticle is preferably in the range of 0.5 to 10 GPa, more preferably in the range of 1 to 5 GPa, when measured according to ISO 527.

[0051] Preferably, the outgassing of the glue or adhesive used to attach the pellicle to the pellicle frame or the pellicle frame to the reticle is <6E-06 [mbar.l / s.cm2], more preferably <8E-09 [mbar.l / s.cm2], even more preferably <8E-10 [mbar.l / s.cm2].

[0052] According to an eighth aspect of the present invention, a pellicle attachment device is provided, comprising: a pellicle manipulator; and a glue dispenser. The pellicle attachment device can be used to prepare at least a portion of a pellicle assembly from a first article and a second article. The pellicle manipulator can be configured to bring the first article into contact with the second article. The glue dispenser can be configured to provide PMMA glue as one or more components. The glue dispenser can be configured to provide at least one component of the PMMA glue to the surface of the first article. The glue dispenser can be configured to provide at least one component of the PMMA glue to the surface of the second article. The glue dispenser can be configured to provide at least one component of the PMMA glue to the surface of the first article and provide at least one component of the PMMA glue to the surface of the second article. When the first article is in contact with the second article, the first article can be attached to the second article.

[0053] The first article can be a frame. The frame can be a pellicle frame. The second article can be a pellicle (i.e., a film or membrane). When the pellicle assembly is bonded to the pattern forming device, the pellicle frame can be a frame configured to provide an airtight space.

[0054] The second article may be an engagement mechanism.

[0055] The membrane manipulator can include a component for tightening the membrane. For example, the membrane manipulator can tighten the membrane before making the membrane contact the frame.

[0056] According to a ninth aspect of the present invention, a pellicle assembly is provided. The pellicle assembly may include a pellicle. The pellicle assembly may include a frame. PMMA glue may be disposed between the pellicle and the frame and may contact the pellicle and the frame to adhere the pellicle to the frame.

[0057] According to a tenth aspect of the present invention, a patterning device is provided. The patterning device may include a plurality of studs. PMMA glue may be disposed between the patterning device and each of the plurality of studs, and may contact the patterning device and each of the plurality of studs to attach the patterning device to each of the plurality of studs.

[0058] According to an eleventh aspect of the present invention, there is provided a mask assembly comprising: a pellicle assembly according to the ninth aspect of the present invention; and a pattern forming device according to the tenth aspect of the present invention.

[0059] The use of PMMA glue offers several advantages.

[0060] The PMMA glue takes several minutes to cure, which is a much shorter curing process than the curing process of known epoxy glues (which typically takes several hours). Thus, advantageously, using PMMA glue according to some aspects of the present invention to attach the pellicle frame to the pellicle results in a significantly shorter time required to produce the pellicle assembly (compared to using known epoxy glues). Further, advantageously, using PMMA glue to attach the studs to the patterning device requires significantly less time (compared to using known epoxy glues). This has associated advantages for high-volume manufacturing.

[0061] PMMA glue is generally more elastic than epoxy glue. PMMA glue can be removed from a surface (e.g., from the surface of a patterning device) more easily than epoxy glue. Thus, advantageously, once the stud is removed, using PMMA glue to attach the stud to the patterning device (compared to using known epoxy glues) results in easier stud removal and patterning device cleaning procedures.

[0062] A heater and / or oven may be required to heat conventional epoxy adhesives to promote curing. Advantageously, no heat is required to promote curing of PMMA adhesives. This results in a simpler manufacturing process, which may also reduce the risk of defects and damage to manufactured products (such as film components or patterning devices provided with studs).

[0063] According to a twelfth aspect of the present invention, a mask assembly is provided. The mask assembly may include a pellicle assembly and a patterning device. The pellicle assembly may include a pellicle and a frame. An adhesive may be disposed between the frame and the patterning device and may contact the frame and the patterning device to attach the frame to the patterning device.

[0064] The adhesive may be provided in a single continuous shape. This shape may generally match the shape of the frame.

[0065] An airtight space may be formed between the pellicle assembly and the patterning device. In such an embodiment, the pellicle assembly is referred to as a "closed frame" system.

[0066] The adhesive may be PMMA glue.

[0067] The mask assembly according to the twelfth aspect of the invention is advantageous for several reasons.

[0068] The mask assembly according to the twelfth aspect of the present invention can provide an airtight space between the pellicle assembly and the patterning device. Advantageously, this can prevent contaminant particles from entering the space and causing errors in the pattern applied to the substrate by the lithographic apparatus.

[0069] The mask assembly according to the twelfth aspect of the invention is particularly advantageous over known arrangements which typically use intermediate fixing members (referred to as studs) that are affixed to the patterning device and engage with the pellicle assembly, as now discussed.

[0070] The mask assembly according to the twelfth aspect of the present invention includes fewer components than a mask assembly that uses intermediate fixing members such as studs (attached to the patterning device) and an engagement mechanism (provided on the pellicle assembly) to engage with the intermediate fixing members (studs). Therefore, the mask assembly according to the twelfth aspect of the present invention can advantageously be manufactured relatively simply. The reduced number of components and simpler manufacturing process can result in lower manufacturing costs.

[0071] With known arrangements using studs bonded to patterning devices, the total contact area between the studs and the patterning device is relatively small. Therefore, typically, the surface area of the patterning device that contacts each stud is etched to form a stud landing pad. In contrast, in the mask assembly according to the twelfth aspect of the invention, the surface area of the patterning device that is attached to the pellicle frame is typically significantly larger than the total area of the patterning device that would be attached to the studs in an alternative design of the mask assembly using studs. Therefore, advantageously, in the mask assembly according to the twelfth aspect of the invention, there is no need to selectively etch the surface of the patterning device (which may be necessary in such alternative designs of the mask assembly to increase the adhesion between the patterning device and one or more studs disposed thereon). Advantageously, this can reduce the manufacturing time and manufacturing costs of the mask assembly according to the twelfth aspect of the invention.

[0072] Due to the curing of PMMA glue (compared to other glues), the material characteristics of PMMA glue, in particular the elasticity of PMMA glue and the dimensions to which PMMA glue can be applied, result in relatively low deformation of the pattern forming device. In contrast, if the pellicle frame is directly attached to the pattern forming device using known epoxy glue, the deformation of the pattern forming device caused by the curing of the epoxy glue can be significantly greater, resulting in errors in the pattern projected onto the substrate by the lithographic equipment. Therefore, by overcoming the problems associated with the use of known epoxy glues, the use of PMMA glue enables the production of an improved mask assembly according to the twelfth aspect of the present invention.

[0073] Compared to known epoxy glues, PMMA glue is easier to remove and is relatively more elastic. Advantageously, this can enable the pellicle assembly forming part of the mask assembly according to the twelfth aspect of the invention to be more easily replaced.

[0074] It is to be understood that one or more aspects or features referred to in the above description or in the following description may be combined with one or more other aspects or features. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which:

[0076] - Figure 1 is a schematic diagram of a lithography system including a lithography apparatus and a radiation source;

[0077] - Figure 2 are schematic diagrams of various devices and lithographic apparatus according to embodiments of the present invention;

[0078] - Figure 3 is a perspective view of a mask assembly according to an embodiment of the present invention;

[0079] - Figure 4 yes Figure 3 a cross-sectional view of a portion of a mask assembly;

[0080] - Figure 5 depicts the formation of Figure 3 an engaging mechanism of a portion of a mask assembly;

[0081] - Figure 6 schematically depicts a pellicle frame attachment device according to an embodiment of the present invention;

[0082] - Figure 7 shows a pellicle assembly disposal system according to an embodiment of the present invention;

[0083] - FIG. 8 shows a patterning device handling system according to an embodiment of the present invention;

[0084] - FIG. 9 shows an arrangement of the treatment system shown in FIG. 7 and FIG. 8 according to an embodiment of the present invention;

[0085] - Figure 10 An optical system according to an embodiment of the present invention is shown;

[0086] - Figure 11 An optical system according to another embodiment of the present invention is shown;

[0087] - Figure 12 is a perspective view of a portion of a membrane frame attachment device;

[0088] - Figure 13 A portion of the pellicle frame attachment device is shown in greater detail;

[0089] - Figure 14 The interrelationships between the different parts of the pellicle frame attachment device are schematically depicted;

[0090] - Figure 15 and 16 Schematically depicts the operation of the engagement mechanism by the pellicle frame attachment apparatus;

[0091] - Figure 17 depicts in more detail the operation of the engagement mechanism performed by the membrane frame attachment device;

[0092] - Figure 18 schematically depicts a stud attachment device according to an embodiment of the present invention;

[0093] - Figure 19 a portion of a stud attachment device is depicted in cross section; and

[0094] - Figure 20 Depicted in cross section Figure 19 A variation of the stud attachment device shown;

[0095] - Figure 21 depicts a method of attaching two bodies to each other using a poly(methyl methacrylate) based adhesive; and

[0096] - Figure 22 depicts two designs of mask assemblies according to embodiments of the present invention. DETAILED DESCRIPTION

[0097] Figure 1A lithography system is shown. The lithography system comprises a radiation source SO and a lithography apparatus LA. The radiation source SO is configured to generate an extreme ultraviolet (EUV) radiation beam B. The lithography apparatus LA comprises an illumination system IL, a support structure MT configured to support a mask assembly 15 comprising a patterning device MA (e.g., a mask), a projection system PS, and a substrate table WT configured to support a substrate W. The illumination system IL is configured to condition the radiation beam B before it is incident on the patterning device MA. The projection system is configured to project the radiation beam B (now patterned by the patterning device MA) onto the substrate W. The substrate W may comprise a previously formed pattern. In this case, the lithography apparatus aligns the patterned radiation beam B with the pattern previously formed on the substrate W.

[0098] The radiation source SO, illumination system IL, and projection system PS may all be constructed and arranged so as to be isolated from the external environment. A gas at a pressure below atmospheric pressure (e.g., hydrogen) may be provided in the radiation source SO. A vacuum may be provided in the illumination system IL and / or the projection system PS. A small amount of gas at a pressure well below atmospheric pressure (e.g., hydrogen) may be provided in the illumination system IL and / or the projection system PS.

[0099] Figure 1 The radiation source SO shown is of a type that may be referred to as a laser produced plasma (LPP) source. A laser 1 (which may be a CO2 laser, for example) is arranged to deposit energy into a fuel, such as tin (Sn), provided from a fuel emitter 3, via a laser beam 2. Although tin is referenced in the following description, any suitable fuel may be used. The fuel may, for example, be in liquid form and may, for example, be a metal or alloy. The fuel emitter 3 may include a nozzle configured to direct the tin, for example in the form of droplets, along a trajectory toward a plasma formation region 4. The laser beam 2 is incident on the tin at the plasma formation region 4. Depositing the laser energy into the tin generates a plasma 7 at the plasma formation region 4. During deactivation and recombination of ions in the plasma, radiation, including EUV radiation, is emitted from the plasma 7.

[0100] EUV radiation is collected and focused by a near-normal-incidence radiation collector 5 (sometimes more generally referred to as a normal-incidence radiation collector). Collector 5 can have a multilayer structure arranged to reflect EUV radiation (e.g., EUV radiation having a desired wavelength, such as 13.5 nm). Collector 5 can have an elliptical structure with two elliptical foci. As discussed below, the first focal point can be at the plasma formation region 4, and the second focal point can be at the intermediate focus 6.

[0101] In other embodiments of the laser produced plasma (LPP) source, the collector 5 may be a so-called grazing incidence collector, which is configured to receive EUV radiation at a grazing incidence angle and focus the EUV radiation at an intermediate focus. The grazing incidence collector may, for example, be a nested collector comprising a plurality of grazing incidence reflectors. The grazing incidence reflectors may be arranged axially symmetrically around the optical axis.

[0102] The radiation source SO may include one or more contamination traps (not shown). For example, the contamination trap may be located between the plasma formation region 4 and the radiation collector 5. The contamination trap may be, for example, a rotating foil trap, or may be any other suitable form of contamination trap.

[0103] The laser 1 may be separate from the radiation source SO. In this case, the laser beam 2 may be transferred from the laser 1 to the radiation source SO by means of a beam delivery system (not shown) comprising, for example, suitable orientation mirrors and / or a beam expander and / or other optical devices. The laser 1 and the radiation source SO may be considered together as a radiation system.

[0104] The radiation reflected by the collector 5 forms a radiation beam B. The radiation beam B is focused at a point 6 to form an image of the plasma formation region 4, which acts as a virtual radiation source for the illumination system IL. The point 6 at which the radiation beam B is focused can be referred to as an intermediate focus. The radiation source SO is arranged so that the intermediate focus 6 is located at or near an opening 8 in an enclosure 9 of the radiation source SO.

[0105] A radiation beam B is passed from a radiation source SO into an illumination system IL which is configured to condition the radiation beam. The illumination system IL may include a faceted field mirror arrangement 11' and a faceted pupil mirror arrangement 11. The faceted field mirror arrangement 11' and the faceted pupil mirror arrangement 11 together provide a radiation beam B having a desired cross-sectional shape and a desired angular distribution. The radiation beam B passes from the illumination system IL and is incident on a mask assembly 15 held by a support structure MT. The mask assembly 15 includes a patterning device MA and a pellicle 19 held in place by a pellicle frame 17. The patterning device MA reflects the radiation beam B and patterns it. The illumination system IL may include other mirrors or devices in addition to or instead of the faceted field mirror arrangement 11' and the faceted pupil mirror arrangement 11.

[0106] After reflection from the patterning device MA, the patterned radiation beam B enters the projection system PS. The projection system comprises a plurality of mirrors 13, 14 configured to project the radiation beam B onto a substrate W held by a substrate table WT. The projection system PS may apply a reduction factor to the radiation beam so as to form an image with features that are smaller than corresponding features on the patterning device MA. For example, a reduction factor of 4 may be applied. Although the projection system PS is Figure 1There are two mirrors 13, 14, but the projection system may comprise any number of mirrors (eg six mirrors).

[0107] The lithographic apparatus can, for example, be used in a scanning mode in which the support structure (e.g., mask table) MT and the substrate table WT are scanned synchronously as a pattern imparted to the radiation beam is projected onto the substrate W (i.e., dynamic exposure). The speed and direction of the substrate table WT relative to the support structure (e.g., mask table) MT can be determined by the reduction ratio and image reversal characteristics of the projection system PS. The patterned radiation beam incident on the substrate W may comprise a stripe of radiation. The stripe of radiation may be referred to as an exposure slit. During a scanning exposure, movement of the substrate table WT and support structure MT may cause the exposure slit to travel over an exposure field of the substrate W.

[0108] Figure 1 The radiation source SO and / or the lithographic apparatus shown may include components not shown. For example, a spectral filter may be provided in the radiation source SO. The spectral filter may be substantially transmissive for EUV radiation, but substantially blocking radiation of other wavelengths, such as infrared radiation.

[0109] In other embodiments of the lithography system, the radiation source SO may take other forms. For example, in alternative embodiments, the radiation source SO may include one or more free electron lasers. The one or more free electron lasers may be configured to emit EUV radiation that may be provided to one or more lithography apparatuses.

[0110] As briefly described above, the mask assembly 15 includes a pellicle 19 that is positioned adjacent the patterning device MA. The pellicle 19 is positioned in the path of the radiation beam B so that the radiation beam B passes through the pellicle 19 as it approaches the patterning device MA from the illumination system IL and as it is reflected by the patterning device MA toward the projection system PS. The pellicle 19 comprises a thin film that is substantially transparent to EUV radiation (although it may absorb a small amount of EUV radiation). By EUV transparent pellicle or film that is substantially transparent to EUV radiation is meant herein that the pellicle 19 is transmissive to at least 65%, preferably at least 80%, and more preferably at least 90% of the EUV radiation. The pellicle 19 serves to protect the patterning device MA from particle contamination.

[0111] Although efforts may be made to maintain a clean environment within the lithographic apparatus LA, particles may still be present within the lithographic apparatus LA. Without the pellicle 19, particles may be deposited onto the patterning device MA. Particles on the patterning device MA may adversely affect the pattern imparted to the radiation beam B and the pattern transferred to the substrate W. The pellicle 19 advantageously provides a barrier between the patterning device MA and the environment within the lithographic apparatus LA to prevent particles from being deposited onto the patterning device MA.

[0112] The pellicle 19 is positioned at a distance from the patterning device MA that is sufficient to prevent any particles incident on the surface of the pellicle 19 from being in the plane of field of the lithographic apparatus LA. This separation between the pellicle 19 and the patterning device MA serves to reduce the extent to which any particles on the surface of the pellicle 19 contribute a pattern to the radiation beam B imaged onto the substrate W. It will be appreciated that if a particle is present in the radiation beam B but is located outside the plane of field of the radiation beam B (i.e., not on the surface of the patterning device MA), then any image of the particle will not be in focus at the surface of the substrate W. In the absence of other considerations, it may be desirable to position the pellicle 19 at a considerable distance from the patterning device MA. However, in practice, the space available to accommodate the pellicle in the lithographic apparatus LA is limited due to the presence of other components. In some embodiments, the separation between the pellicle 19 and the patterning device MA may be, for example, approximately between 1 mm and 10 mm, such as between 1 mm and 5 mm, and more preferably between 2 mm and 2.5 mm.

[0113] A mask assembly can be prepared for use in a lithographic apparatus by attaching a pellicle to a pellicle frame and by attaching the pellicle frame to a patterning device. A mask assembly comprising the patterning device MA and the pellicle supported by the pellicle frame near the patterning device can be prepared remotely from the lithographic apparatus LA, and the mask assembly can be delivered to the lithographic apparatus LA for use in the lithographic apparatus LA. For example, the pellicle frame supporting the pellicle can be attached to the patterning device to form the mask assembly at the location where the pattern is imparted to the patterning device. The mask assembly can then be delivered to a separate location where the lithographic apparatus LA is located, and the mask assembly can be provided to the lithographic apparatus LA for use in the lithographic apparatus LA.

[0114] The mask assembly in which the pellicle is held in place by a pellicle frame may be delicate, and the transport of the mask assembly may risk damaging the pellicle. Additionally, assembling the mask assembly to the lithography apparatus LA in a separate environment may result in the mask assembly being exposed to various pressure conditions. For example, the mask assembly may be transported to the lithography apparatus under ambient pressure conditions. The mask assembly may then be loaded into the lithography apparatus LA via a load lock, which is pumped to vacuum pressure conditions. Changes in the pressure conditions to which the mask assembly is exposed may result in a pressure difference across the pellicle, which may cause the pellicle to bend and may risk damaging the pellicle. In an embodiment, the lithography system may include a lithography apparatus LA connected to a pellicle frame attachment device. In this case, the mask assembly including the mask and the pellicle can be transferred directly from the pellicle frame attachment device to the lithography apparatus while being maintained in a controlled environment (e.g., a vacuum environment).

[0115] Figure 2 is a schematic diagram of an apparatus suitable for assembling the mask assembly 15 and transferring the mask assembly to the lithographic apparatus LA. Figure 2 Depicted are a pellicle attachment device 855 that can be used to attach the pellicle 19 to the pellicle frame 17 and a pellicle assembly transport device 881 that can be used to transport the pellicle assembly. Additionally, a stud attachment device 840 is depicted that can be used to attach studs 51 to the pattern forming device MA. The studs 51 allow the pellicle frame 17 (and pellicle 19) to be releasably attached to the pattern forming device MA. Also depicted is a mask transport device 880 that can be used to transport a mask having studs attached thereto. Also depicted is a pellicle frame attachment device 857 that can be used to attach the pellicle frame 17 (and pellicle 19) to the pattern forming device MA to form the mask assembly 15. Mask assembly transport

[0116] Also shown is an apparatus 853 which may be used to transport the mask assembly 15 from the pellicle frame attachment apparatus 857 to the lithographic apparatus LA.

[0117] The pellicle attachment device 855 may be located at a different location than the lithographic apparatus. The stud attachment device 840 may be located at a different location than the lithographic apparatus LA. Alternatively, either or both of the pellicle attachment device 855 and the stud attachment device 840 may be located at the same location as the lithographic apparatus LA (e.g., in a lithographic facility).

[0118] The pellicle attachment device 855 receives the pellicle 19, the pellicle frame 17, and the engagement mechanism (not shown). The pellicle 19 and the pellicle frame 17 can be manually placed in the pellicle attachment device 855. Glue is dispensed into the engagement mechanism-receiving opening in the pellicle frame 17 (e.g., at a location described further below). Glue dispensing can be manual or automated (or partially automated).

[0119] The engagement mechanism and the pellicle frame 17 are aligned relative to one another (eg, using an optical alignment device), and then the engagement mechanism is inserted into the opening in the pellicle frame 17 .

[0120] Glue is also dispensed onto the pellicle frame 17 (e.g., at spaced locations around the pellicle frame 17). Glue dispensing can be manual, or can be automated (or partially automated). An optical alignment system is used to align the pellicle 19 relative to the pellicle frame 17, which is then pressed against the pellicle frame.

[0121] The diaphragm 19 can be manipulated by a diaphragm manipulator which forms part of the diaphragm attachment device 855. The diaphragm manipulator may include a component for tensioning the diaphragm 19. The diaphragm manipulator may tension the diaphragm 19 and hold the diaphragm 19 against the diaphragm frame 17 at room temperature for a period of time sufficient to allow the glue to cure, thereby securing the diaphragm 19 to the diaphragm frame 17. The pressure on the diaphragm 19 is then removed. The glue is then subjected to additional curing at elevated temperatures using a curing oven (which may form part of the diaphragm attachment device 855). This will also cure the glue attaching the joining mechanism to the diaphragm frame 17. In an alternative approach, some heating may be applied to cure the glue while the diaphragm 19 is held against the diaphragm frame (rather than allowing curing to occur at room temperature).

[0122] The glue can be provided by a glue dispenser. The glue dispenser can form part of the pellicle attachment device 855. The glue dispenser can include a syringe. The syringe can dispense a defined volume of one or more components of the glue. The glue dispenser can include a nozzle. For example, the nozzle can be connected to the syringe, and one or more components of the glue can be provided using the syringe connected to the nozzle. The glue can be applied using a cylindrical nozzle. The glue can be applied using a conical nozzle. The glue dispenser can include a brush, and one or more components of the glue can be applied using the brush. The glue dispenser can include a sponge, and one or more components of the glue can be applied using the sponge. The glue dispenser can include a printing device (e.g., a screen printing device) for providing one or more components of the glue. The glue dispenser can include a dispensing device for providing one or more components of the glue as a spray (e.g., an aerosol spray dispensing system can be used). It will be understood that the glue can be provided in any known manner.

[0123] The glue dispenser can provide glue with multiple components (e.g., accelerators and initiators for the glue). One component of the glue may have a higher viscosity than another component of the glue. That is, there may be a glue component with a relatively high viscosity (a "thick" component) and a glue component with a relatively low viscosity (a "thin" component). In an exemplary embodiment, the glue dispenser can use a syringe and nozzle to dispense the thick component of the glue. In an exemplary embodiment, the glue dispenser can use a brush, sponge, screen printing equipment, or an aerosol spray dispensing system to dispense the thin component of the glue.

[0124] Although the use of glue to attach the pellicle 19 to the pellicle frame 17 is described above, the pellicle may be attached to the pellicle frame using any suitable type of bonding, including without the use of glue.

[0125] The resulting pellicle assembly 16 is inspected using a particle inspection tool. The particle inspection tool may form part of the pellicle attachment device 855 (or may be a separate tool). The particle inspection tool may be configured to inspect particles disposed on the pellicle 19 and / or the pellicle frame 17. The particle inspection tool may, for example, reject a pellicle assembly 16 having a particle count greater than a given particle threshold. The particle inspection tool may also be used to inspect the pellicle 19 and / or the pellicle frame 17 before the pellicle and pellicle frame are glued together.

[0126] The pellicle attachment device 855 can be configured to seal the pellicle assembly 16 in the pellicle assembly transport device 881 (sealing box) after inspection. As depicted, the pellicle assembly transport device 881 can be arranged to hold the pellicle assembly in an orientation with the pellicle 19 below the pellicle frame 17. Because the transport device 881 is sealed, the pellicle assembly 16 can be transported without contamination. The pellicle assembly 16 can be transported to the pellicle frame attachment device 857 in the transport device 881.

[0127] The pellicle attachment device 855 may include a clean environment to reduce the number of particles within the sealed environment, thereby reducing the number of particles that can be deposited on the pellicle 19. The pellicle attachment device 855 may be located, for example, at the location where the pellicle is manufactured. In some embodiments, the pellicle 19 may be provided directly to the pellicle attachment device 855 from a pellicle manufacturing tool (not shown) that manufactures the pellicle 19. For example, the pellicle 19 may be provided to the pellicle attachment device 855 from the pellicle manufacturing tool while the pellicle 19 is maintained within a clean environment. This may reduce the chance that the pellicle 19 is contaminated or damaged before being provided to the pellicle attachment device 855. The clean environment may be, for example, a sealed environment (i.e., completely isolated from the external environment). The sealed environment may be pumped to maintain a vacuum in the sealed environment.

[0128] The attachment of diaphragm 19 to diaphragm frame 17 can be controlled to achieve a desired tension in diaphragm 19. For example, the tension in diaphragm 19 can be measured during or after attachment of diaphragm 19 to diaphragm frame 17, and the tension can be adjusted in response to the measurement to achieve a desired tension in diaphragm 19. The tension in diaphragm 19 can be maintained, for example, by applying an outward force to components of diaphragm frame 17 to pull diaphragm 19 taut. The tension in diaphragm 19 can be maintained, for example, by utilizing the difference in thermal expansion coefficients between the diaphragm frame and the diaphragm.

[0129] In an embodiment, the patterning device (which may be referred to as a mask) MA may be provided with protrusions that are accommodated by an engagement mechanism (e.g., as described further below). The patterning device may, for example, accommodate four protrusions (referred to herein as studs). Figure 2 As depicted, a stud attachment apparatus 840 may be used to attach the studs 51 to the patterning device MA.

[0130] The stud 51 and patterning device MA can be manually placed in the stud attachment apparatus 840. The patterning device MA can be maintained in a controlled environment separate from the rest of the stud attachment apparatus 840. The separation or spacing can be provided by a partition 842 having an opening through which the stud 51 can protrude to contact the patterning device MA. The controlled environment can be maintained at a higher pressure than the rest of the stud attachment apparatus 840 (e.g., by delivering gas through an outlet in the controlled environment). This will inhibit or prevent contaminant particles from being transferred from other parts of the stud attachment apparatus into the controlled environment.

[0131] The stud attachment device 840 may include a stud manipulator (not depicted), such as a robot or actuator for accurately placing the studs. An example of a suitable actuator for placing the studs on the patterning device is a Lorentz actuator (not depicted). The stud attachment device 840 may also include a device for automatically providing a fixed amount of glue or adhesive to the surface of the stud to be attached to the patterning device MA. The application of glue or adhesive may also be done manually. Contamination of the patterning device MA by contaminants from the glue or adhesive is prevented or reduced by air flow from a controlled environment above the partitioning zone 842 to below the partitioning zone (the air flow is caused by the pressure above the partitioning zone being higher than the pressure below the partitioning zone).

[0132] The stud attachment device 840 may also include an optical alignment system that aligns the stud relative to the alignment marks present on the mask in order to accurately position the stud. For example, alignment marks conventionally provided on the pattern forming device MA and used for pattern alignment may also be used to align the stud.

[0133] The stud attachment apparatus may comprise a support structure movable in the XYZ and Rz directions for adjusting the position of the patterning device MA. The position of the support structure holding the patterning device MA may be adjusted manually with the aid of coarse and fine adjustment mechanisms, or using an automatic (or semi-automatic) actuator or any other type of device coupled to the patterning device stage suitable for alignment and positioning.

[0134] Once the stud 51 and the patterning device MA have been aligned, the stud 51 is pressed against the patterning device MA. The stud 51 can be held against the patterning device MA at room temperature for a period of time sufficient to allow the glue to cure, thereby securing the stud 51 to the mask MA. Alternatively, the stud 51 can be heated to facilitate the curing of the glue. A curing oven (which can form part of the pellicle attachment device 855) can then be used to perform additional curing of the glue at elevated temperatures.

[0135] The glue can be provided by a glue dispenser. The glue dispenser can form part of the stud attachment device 840. The glue dispenser can include a syringe. The syringe can dispense a defined volume of one or more components of the glue. The glue dispenser can include a nozzle. For example, the nozzle can be connected to the syringe, and one or more components of the glue can be provided using the syringe connected to the nozzle. The glue can be applied using a cylindrical nozzle. The glue can be applied using a conical nozzle. The glue dispenser can include a brush, and one or more components of the glue can be applied using the brush. The glue dispenser can include a sponge, and one or more components of the glue can be applied using the sponge. The glue dispenser can include a printing device (e.g., a screen printing device) for providing one or more components of the glue. The glue dispenser can include a dispensing device (e.g., an aerosol spray dispensing system can be used) for providing one or more components of the glue as a spray. It is to be understood that the glue can be provided in any known manner.

[0136] The glue dispenser can provide glue with multiple components (e.g., accelerators and initiators for the glue). One component of the glue may have a higher viscosity than another component of the glue. That is, there may be a glue component with a relatively high viscosity (a "thick" component) and a glue component with a relatively low viscosity (a "thin" component). In an exemplary embodiment, the glue dispenser can use a syringe and nozzle to dispense the thick component of the glue. In an exemplary embodiment, the glue dispenser can use a brush, sponge, screen printing equipment, or an aerosol spray dispensing system to dispense the thin component of the glue.

[0137] The patterning device MA and the studs 51 may be inspected using a particle inspection tool (which may form part of the stud attachment apparatus 840).

[0138] The stud attaching device 840 seals the patterning device MA and studs 51 in a mask transport device 880 (sealed box). Because the mask transport device 880 is sealed, the patterning device MA and studs 51 can be transported without contaminating the mask MA. The patterning device MA and studs can be transported to the pellicle frame attaching device 857 in the mask transport device 880.

[0139] In an embodiment, the mask MA is provided to the stud attachment apparatus 840 in a sealed box (to reduce the risk of contamination). The box may remain sealed until just before the studs 51 are to be attached to the patterning device MA, minimizing the time that contamination may travel to the mask MA.

[0140] The controlled environment of the stud attachment apparatus 840 can be provided in part by a housing that subsequently forms the patterning device MA transport apparatus 880 (a sealed box). The housing can form the walls and top plate of the mask transport apparatus 880, with the bottom plate of the mask transport apparatus 880 being formed by a plate that is assembled after (e.g., immediately after) the studs 51 have been attached. Using a housing in this manner can help prevent contamination from being incident on the patterning device MA. The housing can include a cover for the transport box. The mask stage of the stud attachment apparatus 840 can be configured to accommodate the housing.

[0141] Similarly, the diaphragm attachment device 855 may also be formed in part by a housing that subsequently forms part of the diaphragm assembly delivery device 881.

[0142] The pellicle assembly 16 in the pellicle assembly conveyor 881 and the patterning device MA (and studs 51) in the mask conveyor 880 are both conveyed to the pellicle frame attaching apparatus 857. The pellicle frame attaching apparatus 857 may be provided in a factory where one or more photolithography apparatuses are also provided.

[0143] The pellicle frame attachment apparatus 857 is configured to attach the pellicle frame 17 of the pellicle assembly 16 to the studs 51 on the patterning device MA to form the mask assembly 15. The pellicle frame attachment apparatus 857 can include a controlled environment that is separate or spaced apart from the rest of the pellicle frame attachment apparatus 857. The separation or spacing can be provided by a partition 862 having an opening through which the manipulator extends (not in the Figure 2 ). The manipulator can be operated by a control system 870 (described further below). The controlled environment can be maintained as a clean environment to reduce the number of particles within the controlled environment, thereby reducing the number of particles that can be deposited on the mask assembly 15. The controlled environment can be maintained at a higher pressure than the rest of the pellicle frame attachment device 857 (e.g., by delivering gas through an outlet in the controlled environment). This will inhibit or prevent contaminating particles from being transferred from other parts of the pellicle frame attachment device 857 into the controlled environment.

[0144] The mask assembly 15 assembled by the pellicle frame attachment device 857 is transported from the pellicle frame attachment device 857 to the lithographic apparatus LA in the mask assembly transport device 853. The mask assembly transport device 853 can include a sealed and clean environment in which the mask assembly 15 is transported. This reduces the chance of the mask assembly 15 being contaminated or damaged during transportation of the mask assembly 15. The sealed and clean environment can be, for example, pumped to a vacuum.

[0145] The pellicle frame attachment device 857 can be used to install, remove or reinstall the pellicle assembly 16 to / from the patterning device MA. The pellicle frame attachment device 857 may include a manipulator arranged to manipulate the engagement mechanism of the pellicle frame 17 (as further described below).

[0146] For example, the patterning device MA can be provided with alignment marks. The pellicle frame 17 can be positioned relative to the alignment marks on the patterning device MA. Aligning the pellicle frame 17 relative to the alignment marks on the patterning device MA can advantageously improve the accuracy with which the pellicle frame 17 is positioned on the patterning device MA during attachment of the pellicle frame 17 to the patterning device MA.

[0147] In some embodiments, the patterning device MA may be cleaned in the pellicle frame attachment apparatus 857, for example to remove particles from the patterning device MA. In other embodiments, cleaning of the patterning device MA may be performed in a dedicated cleaning tool.

[0148] Although the illustrated embodiment shows the pellicle frame 17 being attached to the front of the mask MA, in other embodiments, the pellicle frame 17 can be attached to other parts of the mask MA. For example, the pellicle frame 17 can be attached to the side of the mask MA. This can be achieved, for example, using a sub-mount that provides a releasable, engageable attachment between the pellicle frame 17 and the side of the mask MA. In an alternative arrangement, the pellicle frame 17 can be attached to the mask MA by a combination of some attachment locations on the side of the mask MA and some attachment locations on the front of the mask MA. The attachment can be provided, for example, by a sub-mount that releasably engages the pellicle frame 17 and the mask MA.

[0149] In some embodiments, the pellicle frame attachment device 857 may include a particle inspection tool (not shown). The particle inspection tool may be configured to inspect the mask assembly 15 for particles disposed on the mask assembly 15. The particle inspection tool may, for example, reject mask assemblies 15 that have a particle count greater than a given particle threshold.

[0150] In some embodiments, the pellicle frame attachment apparatus 857 may include a pattern inspection system that inspects the pattern on the patterning device MA for any defects. The pattern inspection system may inspect the pattern on the patterning device MA before and / or after the pellicle frame 17 is attached to the patterning device MA.

[0151] The attachment of the pellicle frame 17 to the patterning device MA can be controlled so as to achieve a desired tension in the pellicle 19. For example, the tension in the pellicle 19 can be measured during attachment of the pellicle frame 17 to the patterning device MA, and the tension can be adjusted in response to the measurement so as to achieve the desired tension in the pellicle 19.

[0152] The lithographic apparatus LA may correspond, for example, to Figure 1 The depicted lithographic apparatus LA. The lithographic apparatus LA may include components configured to receive a mask assembly 15 from a mask assembly transport device 853 and load the mask assembly 15 onto a support structure MT of the lithographic apparatus LA. The mask assembly 15 may be irradiated with a conditioned radiation beam B provided by an illumination system IL. A patterning device MA of the mask assembly 15 may impart a pattern in its cross-section to the conditioned radiation beam to form a patterned radiation beam. The patterned radiation beam may be projected by a projection system PS onto a substrate W held by a substrate table WT. The conditioned radiation beam may, for example, include EUV radiation. In embodiments where the conditioned radiation beam includes EUV radiation, the pellicle 19 of the mask assembly 15 may be substantially transparent to the EUV radiation.

[0153] In some embodiments, the pellicle assembly 16 can be attached to the patterning device MA to form the mask assembly 15 under vacuum conditions in the pellicle frame attachment apparatus 857. The mask assembly 15 can then be transported to the lithography apparatus LA under vacuum conditions by the mask assembly transport apparatus 853 and can be maintained under vacuum conditions in the lithography apparatus LA. Thus, the mask assembly 15 can be exposed to approximately the same pressure conditions throughout its assembly in the pellicle frame attachment apparatus 857 and use in the lithography apparatus LA. This advantageously reduces any pressure variations to which the mask assembly 15 is exposed, and thus reduces any pressure differentials that may develop across the pellicle 19.

[0154] In some embodiments, while the component is held in vacuum, the patterning device MA and / or pellicle 19 can be inspected for particles and / or defects in the pellicle frame attachment apparatus 857. Thus, advantageously, the patterning device MA and / or pellicle 19 are inspected under pressure conditions similar to those to which they are exposed during use in the lithographic apparatus LA. This is advantageous because any particles that may have been deposited onto the patterning device MA and / or pellicle during pumping to vacuum conditions can be detected in the pellicle frame attachment apparatus 857.

[0155] In some embodiments, the lithography system may further include a separate inspection device (not shown) configured to inspect one or more components of the mask assembly 15 for particles and / or defects. After being assembled in the pellicle frame attachment device 857 and before the mask assembly 15 is transported to the lithography apparatus LA, the mask assembly 15 may be transported to the inspection device (e.g., by the mask assembly transport device 853), for example.

[0156] The embodiments of the present invention described above advantageously allow the mask assembly 15 to be assembled and transferred to the lithographic apparatus LA in an automated (or semi-automated) process. Both the assembly and transfer of the mask assembly 15 can be performed in a sealed, clean environment, which can be, for example, pumped to vacuum pressure conditions. This can reduce the chance of contamination or damage to components of the mask assembly 15 before use in the lithographic apparatus LA.

[0157] Typically, the useful life of the pellicle 19 may be less than the useful life of the patterning device MA. Therefore, it may be desirable to remove the pellicle assembly 16 from the patterning device MA and replace the pellicle assembly with a new pellicle assembly to allow continued use of the patterning device MA. For example, replacement of the pellicle assembly 16 can be performed in the pellicle frame attachment apparatus 857. For example, after use in the lithography apparatus LA, the mask assembly 15 can be transferred back to the pellicle frame attachment apparatus 857 using the mask assembly transport apparatus 853 for pellicle assembly replacement in the pellicle frame attachment apparatus 857. After the pellicle assembly 16 is removed, the patterning device MA can be subjected to a cleaning process to remove contamination from the patterning device MA. Before the patterning device is subjected to the cleaning process, the stud 51 can be removed from the patterning device MA.

[0158] It should be noted that in Figure 2 During the various operations depicted, the patterning side of the patterning device MA is oriented downward. Keeping the patterning side of the patterning device MA downward is advantageous because it reduces the likelihood of contaminant particles being incident on the pattern. Larger contaminant particles tend to fall downward due to gravity and are therefore incident on the opposite side of the mask. Smaller contaminant particles are less affected by gravity and may be affected by other transport physics. Apparatus according to embodiments of the present invention may include apparatus designed to address this issue. For example, the apparatus may include an ionizer to remove static charge, thereby reducing the risk of particles becoming attached to the pellicle due to static electricity.

[0159] Mask components in Figure 35 . The pellicle frame 17 and the pellicle 19 are suspended relative to the pattern forming device MA. The pellicle frame 17 is releasably engaged with the pattern forming device MA. The releasable engagement is provided by a mounting table comprising a plurality of sub-mounts 10 (e.g. 2, 3, 4 or even more sub-mounts). The mounting table allows the pellicle frame 17 (and the pellicle 19) to be removed from the pattern forming device MA in an easy and convenient manner. Removal of the pellicle frame 17 and the pellicle 19 from the pattern forming device MA can be clean, i.e. substantially no contaminating particles can be generated. Once the pellicle frame 17 has been removed from the pattern forming device MA, the pattern forming device MA can be inspected using an inspection tool (and can be cleaned if necessary). The pellicle frame 17 and the pellicle 19 can then be easily reattached to the pattern forming device MA, or can be replaced with a new pellicle frame 17 and pellicle 19. Each sub-mount 10 of the mounting table is formed by an engagement mechanism and a protrusion (see below). Figure 4 discussed in more detail).

[0160] First refer to Figure 3 , the pellicle 19 is attached to the pellicle frame 17. The pellicle 19 can, for example, be glued to the pellicle frame 17. The pellicle frame 17 is provided with four engaging mechanisms 50A to 50D. Each engaging mechanism 50A to 50D is arranged on a ramp portion 49A to 49D. The ramp portions 49A to 49D are generally trapezoidal. The ramp portions 49A to 49D are attached to the pellicle frame 17 and protrude from the pellicle frame 17 in the main plane of the pellicle frame 17. Each engaging mechanism 50A to 50D is configured to accommodate a protrusion 51 (which can, for example, be referred to as a stud 51) extending from the pattern forming device MA (as shown below in conjunction with Figure 4 Two engagement mechanisms 50A, 50B are provided on one side of the pellicle frame 17, and two engagement mechanisms 50C, 50D are provided on the opposite side of the pellicle frame 17. Other combinations are possible, such as an engagement mechanism 50 on each of the four frame sides, etc. The engagement mechanisms 50A to 50D are provided on the side of the pellicle frame 17 that will be oriented in the scanning direction during use in the lithographic apparatus LA (according to conventional notation, in the Figure 3 However, the engagement mechanisms 50A to 50D may also be arranged on the side of the pellicle frame 17, which will be oriented perpendicular to the scanning direction during use in the lithographic apparatus LA (according to conventional notation, in Figure 3 is indicated as the x-direction in the figure).

[0161] The protrusions 51 received by the engagement mechanisms 50A to 50D can be located on the front surface of the patterning device MA. Additionally or alternatively, the protrusions 51 can be located on the side of the patterning device MA. The protrusions 51 can extend upward from the side of the patterning device MA. In this arrangement, the protrusions 51 can each have a flat side surface to facilitate secure bonding to a side of the patterning device MA.

[0162] Figure 3 Four engagement mechanisms 50A to 50D are depicted fixed to the pellicle frame 17. Two of the engagement mechanisms 50A, 50D are configured to allow movement in the y-direction (i.e., provide flexibility or compliance in the y-direction). Two of the engagement mechanisms 50B, 50C are configured to allow movement in the x-direction (i.e., provide flexibility or compliance in the x-direction). However, all four engagement mechanisms 50A to 50D are configured to allow movement between the engagement mechanisms 50A to 50D and the protrusion 51 (not depicted) via movement in the y-direction, and therefore, as can be seen, all four engagement mechanisms 50A to 50D include engagement arms 80 extending in the y-direction. A possible disadvantage of this configuration is that a sudden deceleration during the y-direction scanning movement may cause the engagement mechanisms 50A to 50D to slip out of attachment to the protrusion (due to the inertia of the pellicle frame 17). This may occur, for example, if the mask support structure MT 'crashes' (see Figure 1 In an alternative arrangement, all four engagement mechanisms 50A to 50D may include engagement arms 80 extending in the x-direction (i.e., the non-scanning direction). It is advantageous to have all of the engagement arms 80 extend in the non-scanning direction because this avoids the possibility of a sudden deceleration in the y-direction causing the engagement mechanisms 50A to 50D to disengage. Typically, the engagement arms 80 of each engagement mechanism 50A to 50D may extend in substantially the same direction.

[0163] To allow for movement / flexibility in the x-direction, the arms 62 supporting the locking members of the two joint mechanisms 50B and 50C extend in the y-direction. These arms 62 are elastically flexible in the x-direction and therefore provide for movement / flexibility in the x-direction. Therefore, the joint arms 80 of the two joint mechanisms 50B and 50C extend roughly parallel to the arms 62 of those joint mechanisms. To allow for movement / flexibility in the y-direction, the arms 62 supporting the locking members of the other two joint mechanisms 50A and 50D extend in the x-direction. These arms 62 are elastically flexible in the y-direction and therefore provide for movement / flexibility in the y-direction. Therefore, the joint arms 80 of the two joint mechanisms 50A and 50D extend roughly perpendicular to the arms 62 of those joint mechanisms. The movement / flexibility provided by the joint mechanisms 50A to 50D allows the pellicle frame 17 to bend relative to the pattern forming device MA as needed when temperature changes occur. This is advantageous because it avoids potentially destructive thermal stresses generated in the pellicle frame 17.

[0164] Figure 3 The engagement mechanisms 50A to 50D in FIG are depicted with tabs 56 having a different configuration than the tabs 56 depicted in FIG5 . However, the tabs 56 provide the same function of facilitating engagement between the engagement mechanisms 50A to 50D and the diaphragm frame 17. Any suitable configuration of tabs 56 may be used.

[0165] Figure 4 In cross section, a coupling mechanism 50A is depicted along with a protrusion 51 protruding from the patterning device MA. The coupling mechanism 50A and the protrusion 51 together constitute the submount 10. The protrusion 51 (which may be referred to as a stud) may be glued to the patterning device MA, for example, or may be attached by other bonding means (optical contact force, magnetic force, van der Waals force, etc.). The protrusion 51 includes a distal head 53 located on a shaft 55 extending from a base 57. The base 57 is fixed to the patterning device MA, for example, using glue. The shaft 55 and the distal head 53 may be cylindrical, or they may have any other suitable cross-sectional shape.

[0166] The submount 10 suspends the pellicle frame 17 relative to the pattern forming device MA so that a gap G (which can be considered a slit) exists between the pellicle frame 17 and the pattern forming device MA. The gap G can be maintained by the engagement between the cap 66 of the engagement mechanism 50A and the distal head 53 of the protrusion 51 (or by some other movement-limiting component). The gap G can be wide enough to allow pressure balance between the external environment and the space between the pellicle 19 and the pattern forming device MA. The gap G can also be narrow enough to provide desired restrictions on potential routes of contaminants from the external environment to the space between the pellicle 19 and the pattern forming device MA. The gap G can, for example, be at least 100 microns to allow pressure balance between the external environment and the space between the pellicle 19 and the pattern forming device MA. The gap G can, for example, be less than 500 microns, more preferably less than 300 microns. The gap G can, for example, be between 200 microns and 300 microns.

[0167] Figure 5 depicts this in more detail. Figure 4 5. The submount 10 (including the engaging mechanism 50A and the protrusion 51) is shown in FIG5. The pellicle frame 17 attached to the engaging mechanism 50A is not depicted in FIG5. Similarly, the patterning device MA from which the protrusion 51 protrudes is not depicted in FIG5. Figure 5A The submount 10 is shown viewed from below, and Figure 5B The submount 10 is shown in a perspective view as seen from below.

[0168] The engagement mechanism 50A includes a rectangular outer wall 60 received in an opening in the diaphragm frame 17 (see Figure 3 ). A pair of arms 62 extend in the y-direction through the space defined by the outer wall 60. A connecting member 63 extends between the distal ends of the arms 62. The arms 62 are examples of elastic members. Other elastic members may be used. The arms 62 and the connecting member 63 together form a generally U-shaped support. A locking member 70 is connected to the distal end of the generally U-shaped support. The locking member 70 engages with the protrusion 51 (which may be referred to as a stud) to secure the diaphragm frame 17 to the pattern forming device MA.

[0169] The locking member 70 includes a pair of engagement arms 80 equipped with engagement tabs 81 and also includes a cap 66. Figure 5B As best seen in FIG, when the locking member 70 engages the protrusion 51, the engagement tab 81 presses against the lower surface of the distal head 53 of the protrusion 51, and the cap 66 presses against the outer surface of the distal head 53. This pressing of the engagement tab 81 and cap 66 against the distal head 53 of the protrusion 51 secures the engagement mechanism 50A to the protrusion to provide a fixed submount 10. This provides a fixed connection between the diaphragm frame 17 and the patterning device MA.

[0170] The cap 66 and the engagement arm 80 extend from support arms 82a, 82b. The support arms 82a, 82b extend from the connecting member 63 and extend back along the y-direction through the space generally defined by the outer wall 60. The connecting member 83 extends between the support arms 82a, 82b. The support arms 82a, 82b and the connecting member 83 together form a generally U-shaped support.

[0171] Thus, a first generally U-shaped support formed by arms 62 and connecting member 63 extends in the y-direction across the space generally defined by outer wall 60, and a second U-shaped support formed by support arms 82a, 82b and connecting member 83 extends back across that space.

[0172] The arms 62 forming the first generally U-shaped support have some flexibility in the x-direction and this allows some movement of the locking member 70 in the x-direction. Thus, the submount 10 allows some movement of the diaphragm frame relative to the patterning device at the location of the submount in the x-direction. The arms 62 are formed of a resilient material and therefore tend to return to their original orientation. The submount 10 can be considered a moving submount. The arms 62 are significantly thicker in the z-direction than in the x-direction (e.g., in FIG. 1 ). Figure 5B ), the arms 62 may flex significantly less in the z-direction than in the x-direction. Because the arms extend in the y-direction, they do not provide significant movement in the y-direction. The arms 62 may thus prevent or substantially prevent localized movement of the pellicle frame 17 in the y- and z-directions while allowing some movement of the pellicle frame 17 in the x-direction.

[0173] Cap 66 extends from first support arm 82a. Engagement arm 80 extends from second support arm 82b. First support arm 82a is significantly thicker in the x-direction than arm 62, thereby allowing significant movement relative to arm 62 in the x-direction. Second support arm 82b has a similar thickness in the x-direction as arm 62, but a connecting member 83 extending between intermediate arms 82a, 82b inhibits movement of second support arm 82b in the x-direction, as such movement is only possible if first support arm 82a also moves.

[0174] The engagement arm 80 extends from the second support arm 82b in the general direction of the cap 66. The proximal end of the engagement arm 80 extends along the majority of the second support arm 82b (thereby substantially preventing the engagement arm 80 from bending in a direction roughly parallel to the patterned surface of the pattern forming device MA). The engagement arm 80 tapers as they extend in the general direction of the cap 66. The engagement tab 81 extends inwardly from the distal end of the engagement arm 80 to engage with the lower surface of the distal head 53 of the protrusion 51. The block 54 is arranged above the engagement tab 81 and provides an actuator accommodating surface, as further explained below. The engagement arm 80 is elastically deformable in the z direction. The engagement arm 80 can be thin enough so that they bend in the z direction. Additionally or alternatively, some bending of the engagement arm 80 in the z direction can be promoted by a groove 59 extending in the y direction at the point where the engagement arm 80 is connected to the support arm 82b.

[0175] Tabs 56 extend outwardly from the outer wall 60. Tabs 56 can be used to secure the engagement mechanism 50A to the diaphragm frame. Figure 3 , but with tabs 56 having a different configuration.

[0176] An embodiment of the membrane frame attachment device 857 is Figure 6 The membrane frame attachment device 857 may correspond to Figure 2 Membrane frame attachment device 857 is shown. Figure 6 The pellicle frame attachment device 857 is schematically shown in cross section. The mask assembly 15 comprises a patterning device MA provided with a pellicle frame 17 and a pellicle 19 (not depicted). The frame 17 is provided with four engagement mechanisms 50 corresponding to the above engagement mechanisms. Figure 3 5. The pin 1090 of the pellicle frame attachment device 857 protrudes through the hole 895 in the partition 862. The partition 862 can correspond to the support structure 101 or be located on top of the support structure 101. Windows 893, 894 are located in the support structure 101, and the imaging sensors 105, 106 are located below the windows 893, 894. Alignment marks 109 are provided on the windows 893, 894. Alignment marks 704 are also provided on the patterning device MA.

[0177] An additional support structure 97 is provided at the periphery of the pellicle frame attachment device 857. The additional support structure can have a fixed position (as depicted) and is referred to herein as a fixed support structure 97. An intermediate support structure 98 is provided on top of the fixed support structure 97. The intermediate support structure 98 extends inwardly from the fixed support structure 97, as depicted. The intermediate support structure 98 supports the pellicle frame 17 and the pattern forming device MA before the pellicle frame 17 is attached to the pattern forming device MA. The contacts 99 between the intermediate support structure 98 and the other entities can be, for example, a kinematic connection. The contacts 99 can be provided with a polyetheretherketone (PEEK) coating.

[0178] In use, the pellicle assembly 16 is loaded into the pellicle frame attachment device 857. It can be transferred to the pellicle frame attachment device 857 without exposing it to contamination. For example, the pellicle assembly transfer device 881 can be housed in a load lock or controlled flow environment within the pellicle frame attachment device 857, and the pellicle assembly 16 can be removed from the transfer device within the load lock or controlled flow environment. The pellicle assembly 16 can then be transferred to the controlled environment above the segmentation area 862.

[0179] The pellicle assembly 16 can be positioned relative to the pellicle frame attachment device 857, for example, using a pellicle assembly handling system. The pellicle assembly handling system can include a pellicle assembly holder. An example of a pellicle assembly holder 400 is shown in FIG. 7 . Figure 7A A top view of the diaphragm assembly holder 400 is shown. Figure 7A Also shown is the diaphragm assembly 16 . Figure 7A The membrane assembly 16 shown may correspond to Figure 3 The membrane assembly 16 is shown. Figure 7B A perspective view of a pellicle assembly holder 400 is shown. The pellicle assembly holder 400 includes: a first arm 402a; a second arm 402b; a plurality of pellicle assembly aligners 406; and a plurality of pellicle assembly support pads 408.

[0180] The first arm 402a and the second arm 402b each include a base portion 410 and a clamping portion 412. The base portion 410 of each of the first arm 402a and the second arm 402b is movably attached to the diaphragm assembly clamp control device 422. Specifically, the base portion 410 of each of the first arm 402a and the second arm 402b is rotatably or pivotally attached to the diaphragm assembly clamp control device 422. Each of the first arm 402a and the second arm 402b can be described as movable between at least an open position and a closed position. The gap 414 between the clamping portion 412 of the first arm 402a and the clamping portion 412 of the second arm 402b can be varied. The gap 414 can be varied by moving either or both of the first arm 402a and the second arm 402b. The gap 414 can be varied using a diaphragm assembly clamp control knob 424 that forms part of the diaphragm assembly clamp control device 422. The diaphragm assembly holder control knob 424 is configured such that rotation thereof changes the position and / or rotation of the arms 402a, 402b, thereby changing the gap 414. The diaphragm assembly holder 400 can be described as being in an open configuration or a closed configuration. The open configuration of the diaphragm assembly holder 400 can correspond to the first arm 402a and the second arm 402b of the diaphragm assembly holder 400 defining a gap 414 that is wider than the gap 414 that exists when the diaphragm assembly holder 400 is in the closed configuration. In Figure 7, the diaphragm assembly holder 400 is shown in a closed configuration. In the closed configuration of the diaphragm assembly holder 400, the size of the gap 414 is approximately the same as the outer dimension of the diaphragm frame 17. In the open configuration of the diaphragm assembly holder 400, the gap 414 is greater than the outer dimension of the diaphragm frame 17.

[0181] The plurality of membrane assembly aligners 406 and the plurality of membrane assembly support pads 408 are arranged such that at least one membrane assembly aligner 406 and at least one membrane assembly support pad 408 are disposed on the clamping portion 412 of each arm 402a, 402b. The membrane assembly holder 400 shown in FIG7 includes two membrane assembly aligners 406 and two membrane assembly support pads 408 on each arm 402a, 402b. Each membrane assembly aligner 406 is disposed within the gap 414. Each membrane assembly support pad 408 is disposed within the gap 414. The surfaces of the generally cubic bodies 416 of the membrane assembly aligners 406 and the membrane assembly support pads 408 can be generally flat. Specifically, the surfaces of the generally cubic bodies 416 of the membrane assembly aligners 406 and the membrane assembly support pads 408 that face the gap 414 can be generally flat. Each membrane assembly support pad 408 includes a generally cubic body 416 provided with a shelf 420. Each shelf 420 protrudes from a corresponding generally cuboid body 416. Each shelf 420 protrudes into the gap 414. Each support pad 408 can be described as being generally L-shaped. The protruding portion of the support pad 408 (i.e., the shelf 420) can be described as providing a lug. The shelf 420 of the support pad 408 is shaped and arranged to support

[0182] Each shelf 420 is configured to support the slope portion 49 of the membrane assembly 16 (see Figure 3 Specifically, the shelf 420 of the support pad 408 is shaped and configured to support the sloped portion 49 of the pellicle frame 17 when the pellicle assembly 16 is placed in the clamping portion 412 of the pellicle assembly holder 400 and when the pellicle assembly holder 400 is in a closed configuration. The shelf 420 of the support pad 408 is configured to partially contact the surface of the sloped portion 49 of the pellicle assembly 16 and apply a force thereto that is substantially perpendicular to the plane of the pellicle assembly 16 to support the pellicle assembly 16.

[0183] Each pellicle assembly aligner 406 includes a generally cubic body 416 attached to an alignment head 418. Each alignment head 418 protrudes from a portion of the corresponding generally cubic body 416. Each alignment head 418 protrudes into the gap 414. Each alignment head 418 can be circular. The alignment heads 418 of the aligner 406 are shaped and arranged to contact a portion of the pellicle frame 17. Each alignment head 418 is configured to be able to contact an edge of the sloped portion 49 of the pellicle assembly 16 (see Figure 3Specifically, the alignment head 418 of the support pad 408 is shaped and configured to ensure that the diaphragm frame 17 is in a predetermined position when the diaphragm assembly 16 is placed within the clamping portion 412 of the diaphragm assembly holder 400 and when the diaphragm assembly holder 400 is in a closed configuration. The alignment head 418 of the aligner 406 is configured to partially contact the surface of the ramp portion 49 of the diaphragm assembly 16 and apply a force thereto generally in the plane of the diaphragm assembly 16 to align the diaphragm assembly 16.

[0184] The plurality of pellicle assembly aligners 406 and the plurality of pellicle assembly support pads 408 may be formed of PEEK. Alternatively, the plurality of pellicle assembly aligners 406 and / or the plurality of pellicle assembly support pads 408 may be formed of different materials.

[0185] The components of the membrane assembly holder 400 can be formed according to user requirements. Each of the first arm 402a and the second arm 402b can be formed by a continuous section of material. Each of the first arm 402a and the second arm 402b can be formed by multiple sub-segments of material. Each of the first arm 402a and the second arm 402b can include one or more cutouts (e.g., gaps, pores, or recesses). The cutouts may be beneficial for reducing the weight of the arms 402a, 402b. The cutouts may be beneficial for reducing the manufacturing cost of the arms 402a, 402b. The cutouts can be formed so that the cutouts do not include sharp corners. The corners of the cutouts may be rounded. The rounded corners of the cutouts may be beneficial for reducing mechanical stress within the structure in which the cutouts are provided (relative to the structure in which the rounded corners are not provided). In Figure 7, the first arm 402a includes a single cutout with rounded corners, and the second arm includes two cutouts with rounded corners.

[0186] The cutouts can provide internal hinge points 419 (e.g., formed as living hinges). The cutouts can be shaped so that they provide end stops for any movement enabled by the hinge points. The cutouts can be described as being a movable portion of the structure that makes up the diaphragm assembly holder 400. Advantageously, the cutouts can reduce friction between the components (relative to using a standard hinge). Lower friction can result in less particle generation and subsequent contamination. Further, the cutouts can reduce tolerance stacking (relative to using a standard hinge).

[0187] The patterning device MA (with studs 51) can be transferred to the pellicle frame attachment device 857 without exposing it to contamination. For example, the mask transport device 881 can be housed in a load lock or controlled flow environment within the pellicle frame attachment device 857, and the patterning device MA can be removed from the transport device within the load lock or controlled flow environment. The patterning device MA can then be transferred to the controlled environment above the segmentation area 862.

[0188] The patterning device MA may be positioned relative to the pellicle frame attachment apparatus 857, for example using a patterning device handling system. The patterning device handling system may comprise a patterning device holder. An example of a patterning device holder 500 is shown in FIG8 . Figure 8A A top view of the patterning device holder 500 is shown. Figure 8B A perspective view of a patterning device holder 500 is shown. The patterning device holder 500 comprises: a first arm 502a; a second arm 502b; a third arm 502c; a plurality of patterning device aligners 506; and a plurality of patterning device support fingers 508.

[0189] Each of the first arm 502a and the second arm 502b is generally L-shaped. Each of the first arm 502a and the second arm 502b includes a base portion 501 and a distal portion 503. The base portion 501 and the corresponding distal portion 503 are generally perpendicular to each other. The base portion 501 of each of the first arm 502a and the second arm 502b extends from the pattern forming device clamp control device 522. The base portion 501 of the first arm 502a and the base portion 501 of the second arm 502b are generally perpendicular to each other. The shape of the third arm 502c is generally the same as the base portion 501 of the second arm 502b. The third arm 502c does not include a distal portion. Figure 8A In the top view of the patterning device holder 500 shown, the third arm 502c is substantially hidden from view by the second arm 502b. The third arm 502c can be described as being disposed below the base portion 501 of the second arm 502b. Figure 8A and 8B The third arm 502a is typically hidden from view, so area 516 is provided in these figures, which illustrates the spatial extent of the third arm (below the second arm 502b).

[0190] The base portion 501 of each of the arms 502a, 502b, 502c is fixed to the patterning device gripper control apparatus 522. The base portion 501 of each of the arms 502a, 502b, 502c is movably attached to the patterning device gripper control apparatus 522. Specifically, the base portion 501 of each of the arms 502a, 502b, 502c is rotatably or pivotally attached to the patterning device gripper control apparatus 522. The point at which each of the arms 502a, 502b, 502c is attached to the patterning device gripper control apparatus 522 may be spring loaded. Each of the arms 502a, 502b, 502c is rotatable (relative to the patterning device gripper control device 522) about an axis defined by a point, wherein each of the arms 502a, 502b, 502c is movably attached to the patterning device gripper control device 522. Each of the arms 502a, 502b, 502c can be described as being movable between at least an open position and a closed position. The angle between the base portion 501 of the arm 502a and the base portion 501 of the arms 502b, 502c can be changed by movement of the arms 502a, 502b, 502c. However, when each of the arms 502a, 502b, 502c is disposed in the closed position, the base portion 501 of the arm 502a is substantially perpendicular to the base portion 501 of the arms 502b, 502c. The arms 502a, 502b, 502c are shaped and arranged such that the arms 502a, 502b, 502c define a generally rectangular space 514 therebetween.

[0191] The size and shape of the generally rectangular space 514 can be varied. The size and shape of the generally rectangular space 514 can be varied by moving the arms 502a, 502b, 502c relative to the patterning device gripper control device 522. The size and shape of the generally rectangular space 514 can be varied using a patterning device gripper control knob 524 that forms part of the patterning device gripper control device 522. The patterning device gripper control knob 524 is configured such that its rotation changes the position and / or rotation of the arms 502a, 502b, 502c (relative to the patterning device gripper control device 522), thereby changing the size and shape of the generally rectangular space 514. The patterning device gripper 500 can be described as being in an open configuration or a closed configuration. The open configuration of the patterning device holder 500 can correspond to the arms 502a, 502b, 502c of the patterning device holder 500 defining a substantially rectangular space 514 that is larger than the substantially rectangular space 514 when the patterning device holder 500 is in the closed configuration. In FIG8 , the patterning device holder 500 is shown in the closed configuration. In the closed configuration of the patterning device holder 500, the substantially rectangular space 514 has dimensions similar to, but slightly smaller than, the two outer dimensions of the patterning device MA. When the patterning device holder 500 is in the closed configuration, the spring-loaded connection between each of the arms 502a, 502b, 502c and the patterning device holder control device 522 allows the substantially rectangular space 514 to be increased to the size of the two outer dimensions of the patterning device MA. In the open configuration of the patterning device holder 500, the substantially rectangular space 514 is larger than the space defined by the two outer dimensions of the patterning device MA.

[0192] Each patterning device supporting finger 508 includes a protrusion 510. Each protrusion 510 protrudes from one of the arms 502a, 502b, 502c into a generally rectangular space 514. In the patterning device holder 500 shown in FIG8 , one patterning device supporting finger 508 is attached to the base portion 501 of the first arm 502a, one patterning device supporting finger 508 is attached to the distal portion 503 of the first arm 502a, and one patterning device supporting finger 508 is attached to the base portion 501 of the second arm 502b.

[0193] The protrusions 510 of the patterning device support fingers 508 can be described as providing lugs. The protrusions 510 of the patterning device support fingers 508 are shaped and configured to support portions of the patterning device MA. Specifically, when the patterning device MA 16 is placed within the generally rectangular space 514 and when the patterning device holder 500 is in the closed configuration, the protrusions 510 of the support fingers 508 are shaped and configured to support portions of the patterning device MA. The protrusions 510 of the patterning device support fingers 508 are configured to locally contact a surface of the patterning device and apply a force generally perpendicular to the plane of the patterning device to support the patterning device.

[0194] Each patterning device aligner 506 comprises a generally cylindrical member. The generally cylindrical member can be described as a wheel. Each patterning device aligner 506 is attached to one of the arms 502a, 502b, 502c using an axis and one or more supplementary members so that each patterning device aligner 506 is rotatable about its longitudinal axis. Each patterning device aligner 506 protrudes from one of the arms 502a, 502b, 502c into the generally rectangular space 514. In the patterning device holder 500 shown in FIG8 , one patterning device aligner 506 is attached to the base portion 501 of the first arm 502a, one patterning device aligner 506 is attached to the distal portion 503 of the first arm 502a, one patterning device aligner 506 is attached to the third arm 502c, and two patterning device aligners 506 are attached to the distal portion 503 of the second arm 502b. The patterning device aligner 506 is shaped and arranged to contact a portion of the patterning device MA. Specifically, the patterning device aligner 506 is shaped and arranged to ensure that the patterning device MA is in a predetermined position when the patterning device MA is placed within the generally rectangular space 514 and when the patterning device holder 500 is in the closed configuration. The patterning device aligner 506 is configured to locally contact a surface of the patterning device MA and apply a force thereto generally in the plane of the patterning device MA to align the patterning device MA.

[0195] The plurality of patterning device aligners 506 and the plurality of patterning device support fingers 508 may be formed of PEEK. Alternatively, the plurality of patterning device aligners 506 and / or the plurality of patterning device support fingers 508 may be formed of different materials.

[0196] The components of the patterning device holder 500 can be formed according to user requirements. Each of the arms 502a, 502b, 502c can be formed from a continuous section of material. Each of the arms 502a, 502b, 502c can be formed from multiple sub-sections of material. Each of the arms 502a, 502b, 502c can include one or more cutouts (e.g., gaps, holes, or recesses). The cutouts may be useful for reducing the weight of the arms 502a, 502b, 502c. The cutouts may be useful for reducing the manufacturing cost of the arms 502a, 502b, 502c. The cutouts may be formed so that they do not include sharp corners. The corners of the cutouts may be rounded. The rounded corners of the cutouts may be useful for reducing mechanical stress within the structure in which the cutouts are provided (as opposed to in which rounded corners are not provided). Each of the arms 502a, 502b, 502c of the patterning device holder 500 shown in Figure 8 includes multiple cutouts with rounded corners.

[0197] The cutouts can provide internal hinge points 419 (e.g., formed as living hinges). The cutouts can be shaped so that they provide end stops for any movement enabled by the hinge points. The cutouts can be described as movable portions of the structure that make up the patterning device holder 500. Advantageously, the cutouts can reduce friction between components (relative to using standard hinges). Lower friction can result in less particle generation and subsequent contamination. Further, the cutouts can reduce tolerance stacking (relative to using standard hinges).

[0198] Figure 9A An example arrangement 200 is shown, comprising Figure 7A and 7B The membrane assembly holder 400 and Figure 8A and 8B A patterning device holder 500 is shown.

[0199] like Figure 9A As shown, first arm 402a, second arm 402b, and pellicle assembly gripper control device 422 are attached to first intermediate member 426. First intermediate member 426 includes: a handle 428; a vertical control knob 430; and a locking block 432. Similarly, patterning device gripper control device 522 is attached to second intermediate member 526. Second intermediate member 526 includes: a handle 528; a vertical control knob 530; and a locking block 532. First intermediate member 426 is attached to damper assembly 201. Second intermediate member 526 is attached to damper assembly 202.

[0200] The damper assembly 202 is Figure 9BThe damper assembly 202 includes a body 210 having a cavity 212 and a damper mechanism 214 disposed within the cavity 212. The damper mechanism 214 includes a piston housing 204, a piston 206, and a fastening device 208. The piston 206 is movable relative to the piston housing 204. The piston 206 is movable relative to the piston housing 204 in generally only one dimension. This dimension may be the z dimension (see Figure 9A and 9B The piston 206 is movably attached to the end of the piston housing 204 so that the degree to which the piston 206 is contained within the piston housing 204 can be varied. Unless acted upon by an external force, the piston 206 will generally remain stationary. The function of the piston 206 is to dampen movement. Damping can be achieved using a hydraulic damping mechanism within the piston housing 204. The damper mechanism 214 is capable of inhibiting movement of the piston 206 (relative to the piston housing 204) in one dimension in which the piston 206 can move. A fastening device 208 is fixed to the end of the piston 206 that is opposite the end of the piston 206 that is adjacent to the piston housing 204.

[0201] exist Figure 9A In the illustrated arrangement 200, a second intermediate member 526 supports the patterning device holder 500 and is secured to the fastening device 208. A vertical control knob 530 is operable to raise or lower the position of the patterning device holder 500. This may be useful for positioning the patterning device MA using the patterning device holder 500. The vertical control knob 530 may be manually operated. Vertical (z-direction in FIG. 9 ) movement of the patterning device holder 500 may be damped by the damper assembly 202. Specifically, vertical movement of the patterning device holder 500 caused by use of the vertical control knob 530 may be damped by the damper assembly 202. Furthermore, to secure the second intermediate member 526 to the fastening device 208, the second intermediate member 526 may also be attached to the damper assembly 202 via other components while still allowing the damper mechanism 214 to damp movement of the patterning device holder 500.

[0202] It will be appreciated that the first intermediate member 426 and the damper assembly 201 can include substantially the same components as the second intermediate member 526 and the damper assembly 202, respectively. It will also be appreciated that the first intermediate member 426 and the damper assembly 201 can provide substantially the same functionality as the second intermediate member 526 and the damper assembly 202, respectively. Specifically, vertical movement of the diaphragm assembly holder 400 can be achieved via the vertical control knob 430, and vertical movement of the diaphragm assembly holder 400 can be inhibited by the damper assembly 201.

[0203] Each of the damper assembly 201 and the damper assembly 202 is movably attached to the rail 218. The second intermediate member 526 supports the patterning device holder 500 and is attached to the fastening device 208 of the damper assembly 202. The first intermediate member 426 supports the pellicle assembly holder 400 and is attached to a fastening device in the damper assembly 201 that is identical to the fastening device 208 of the damper assembly 202.

[0204] Locking block 432 Figure 9C , shown in greater detail in FIG. The locking block 432 includes a housing 222, a pin 224, a pin shank 226, a wheel 228, and a plurality of fastening bolts 230. The housing 222 of the locking block 432 is secured to the first intermediate member 426 and the damper assembly 201 using the plurality of fastening bolts. The pin 224 is disposed within the housing 222 and protrudes from two opposing sides of the housing 222. The pin shank 226 is attached to one end of the pin 224. A wheel 228 is disposed at the end of the pin 224 opposite the pin shank 226, such that the pin 224 protrudes through a central aperture of the wheel 228. The wheel 228 and the pin 224 share a common longitudinal axis. The wheel 228 is attached to the housing 222 such that the wheel 228 is operable to rotate about the common longitudinal axis of the wheel 228 and the pin 224. The wheel 228 may be attached to the housing 222 using a mechanism including ball bearings. Another ball bearing mechanism can be provided between the pin 224 and the wheel 228. The pin 224 is operable to move in a direction parallel to the common longitudinal axis of the wheel 228 and the pin 224. A mechanism contained within the housing 222 (such as a spring mechanism) biases the pin 224 to a balanced position in which the pin 224 protrudes a predetermined amount from the surface of the housing 222. The pin handle 226 can be operated to move the pin 224 in a direction parallel to the common longitudinal axis of the wheel 228 and the pin 224. Specifically, the pin handle 226 can be manually pulled, causing the pin 224 to move in a direction toward the pin handle 226. When the pin handle 226 is not operated, the mechanism contained within the housing 222 (such as a spring mechanism) returns the pin 224 to its balanced position.

[0205] Figure 9D The track 232, 234 is shown with the rail 218 highlighted. The wheel 228 of the locking block 432 is sized so that the wheel 228 fits within the first track 232 disposed within the rail 218. The first track 232 defines a generally straight path parallel to the x-direction (see Figure 9D Use handle 428 (see Figure 9A), the diaphragm assembly holder 400 can be manually moved along the first track 232 in the track 218. The locking block 432 can be used to lock and unlock the position of the diaphragm assembly holder 400 relative to the first track 232 in the track 218. When the locking block 432 is not operated, the pin 224 protrudes from the housing 222 and engages the track 218, so that the position of the diaphragm assembly holder 400 along the path defined by the first track 232 is fixed. Pulling the pin handle 226 at least partially retracts the pin 224 into the housing 222, the pin 224 no longer engages the track 218, and the diaphragm assembly holder 400 can be moved along the path defined by the first track 232 using the handle 428.

[0206] The locking block 532 is identical to the locking block 432. The housing of the locking block 532 is secured to the second intermediate member 526 and the damper assembly 202 using a plurality of fastening bolts in an arrangement equivalent to that described above for the locking block 432, the first intermediate member 426, and the damper assembly 201. The wheels of the locking block 532 are sized so that they fit within the second track 234 disposed within the rail 218, as shown. Figure 9D The second track 234 defines a path, a portion of which is generally a straight line parallel to the x-direction and a portion of which has a component in the z-direction (see Figure 9D ) so that the second track 234 is partially disposed below the first track 232. Using the handle 528 (see Figure 9A ), the patterning device holder 500 can be manually moved along the second track 234 in the track 218. The locking block 532 provides a mechanism for locking and unlocking the position of the patterning device holder 500 relative to the second track 234 in the track 218, similar to the locking block 432 described above.

[0207] The locking blocks 432, 532 are operable to lock the position of the clamps 400, 500. This may be useful when using the clamps 400, 500 to provide the pellicle assembly 16 and patterning device MA to the intermediate support structure 98 of the pellicle frame attachment apparatus 857 (see Figure 6 ), as described in more detail below. Further, moving the pellicle assembly holder 400 along the first track 232 or the patterning device holder 500 along the second track 234 typically requires the use of two hands (one hand holding the handle 428, 528 and the other hand operating the pin handle 226). This can prevent accidental operation of the vertical control knob 430, 530 during movement of the holder 400, 500 relative to the tracks 232, 234. This can be described as a safety mechanism.

[0208] The pellicle assembly holder 400 is operable to hold the pellicle assembly 16. The pellicle assembly holder 400 and / or the pellicle assembly 16 can be deployed so that when the pellicle assembly holder 400 is in an open configuration, the first arm 402a and the second arm 402b surround the pellicle assembly 16. The arms 402a, 402b of the pellicle assembly holder 400 can then be moved using the pellicle assembly holder control knob 424 so that the pellicle assembly holder 400 is in a closed configuration. The pellicle assembly 16 can be grasped by this action. A plurality of pellicle assembly aligners 406 ensure that the pellicle assembly 16 is in a desired position. A plurality of pellicle assembly support pads 408 support the pellicle assembly 16. Specifically, the pellicle assembly 16 is provided to the pellicle assembly holder 400, and the protrusion 420 of the support pad 408 is arranged to contact the side of the pellicle frame 17 that does not face the pattern forming device MA. The pellicle assembly aligner 406 and the pellicle assembly support pad 408 (and no other components) are in direct contact with the pellicle frame 17 of the pellicle assembly 16. Therefore, only a small portion of the circumference of the pellicle frame 17 is connected using the pellicle assembly clamp 400. Advantageously, this can reduce the risk of particle contamination of the pellicle assembly 16 compared to a clamp that contacts more of the circumference of the pellicle frame 17.

[0209] Membrane assembly holder 400 and control system 870 (see Figure 6 ) can form part of the pellicle frame attachment device 857. The pellicle assembly gripper 400 (grasping the pellicle assembly 16) and / or the control system 870 can be deployed so that the pellicle assembly 16 is positioned above the segmentation region 862 of the pellicle frame attachment device 857. By switching the pellicle assembly gripper 400 to an open configuration using the pellicle assembly gripper control knob 424, the pellicle assembly gripper 400 can then release the pellicle assembly 16 onto the intermediate support structure 98 (see Figure 6 ).

[0210] The patterning device holder 500 is operable to hold the patterning device MA. The patterning device holder 500 and / or the patterning device MA can be maneuvered so that when the patterning device holder 500 is in the open configuration, the arms 502a, 502b, 502c surround the patterning device MA. The arms 502a, 502b, 502c can then be moved using the patterning device holder control knob 524 so that the patterning device holder 500 is in the closed configuration. This action allows the patterning device MA to be grasped. A plurality of patterning device aligners 506 ensure that the patterning device MA is in the desired position. A plurality of patterning device support fingers 508 support the patterning device MA. The patterning device aligners 506 and the patterning device support fingers 508 (and no other components) are in direct contact with the patterning device MA. Therefore, only a small portion of the patterning device MA is in contact with the patterning device holder 500. Advantageously, this may reduce the risk of contaminating the patterning device MA with particles compared to a holder that contacts more of the patterning device MA.

[0211] Patterning device holder 500 and control system 870 (see Figure 6 ) may form part of the pellicle frame attachment device 857. The patterning device holder 500 (holding the patterning device MA) and / or the control system 870 may be deployed so that the patterning device MA is positioned above the segmentation region 862 of the pellicle frame attachment device 857. The patterning device holder 500 may then release the patterning device MA onto the intermediate support structure 98 of the pellicle frame attachment device 857 so that, as described above, the patterning device MA is positioned above the pellicle assembly 16 that has been placed on the intermediate support structure 98. The patterning device holder 500 may release the patterning device MA by switching the patterning device holder 500 to an open configuration using the patterning device holder control knob 524.

[0212] The patterning device MA can be damaged by, for example, dropping the patterning device MA. For example, the patterning device MA can be damaged by dropping it into the generally rectangular space 514 of the patterning device holder 500. Because the second intermediate member 526 is attached to the rail 218 via the damper assembly 202, movement of the patterning device holder 500 parallel to the z-axis is suppressed. The damper assembly 202 can thus reduce the impact force of dropping the patterning device MA into the generally rectangular space 514 of the patterning device holder 500. Advantageously, this can reduce damage to the patterning device MA.

[0213] As described above, maneuvering the pellicle assembly holder 400 may involve moving the pellicle assembly holder 400 relative to the first track 232 of the rail 218. This may be performed manually. The handle 428 may be used for manual movement of the pellicle assembly holder 400. As described above, maneuvering the patterning device holder 500 may involve moving the patterning device holder 500 relative to the second track 234 of the rail 218. This may be performed manually. The handle 528 may be used for manual movement of the patterning device holder 500. The rail 218 may form part of the pellicle frame attachment device 857.

[0214] What you need to understand is that in Figure 9A In an alternative arrangement to the arrangement 200 shown, either or both of the first intermediate member 426 and the second intermediate member 526 may be movably attached directly to the rail 218 (i.e., without providing the damper assemblies 201, 202). As a further alternative, the pellicle assembly holder 400 and the patterning device holder 500 may be movably attached (with or without the damper assemblies 201, 202) to separate rails. These separate rails may form part of the pellicle frame attachment apparatus. The pellicle assembly holder 400 and the patterning device holder 500 may be movably attached to a common rail 218 (e.g., Figure 9A Arrangement 200, as shown, may allow for more accurate relative positioning of the pellicle assembly 16 and the patterning device MA.

[0215] The pellicle assembly holder 400 and the patterning device holder 500 have been described above in the context of the pellicle frame attachment apparatus 857. It will be appreciated that the pellicle assembly holder 400 and the patterning device holder 500 are operable to manipulate the pellicle assembly 16 and the patterning device MA, respectively, for other applications. For example, the pellicle assembly holder 400 can be used to handle the pellicle assembly 16 in the pellicle attachment apparatus 855 (see Figure 2 As yet another example, the patterning device holder 500 may be used to handle the patterning device MA in the stud attachment apparatus 840 (see Figure 2 When the pellicle assembly holder 400 and the patterning device holder 500 are used in other applications, the advantages of the pellicle assembly holder 400 and the patterning device holder 500 described above will generally apply.

[0216] Reference Figure 6 The diaphragm frame attachment device 857 includes an actuator 111 that can be used to adjust the position of the diaphragm assembly 16 in the x, y, and z directions and to rotate the diaphragm assembly about the z direction.

[0217] The partitioning region 862 is provided with four windows 893, 894. The windows 893, 894 may be formed, for example, of quartz. Two of the windows 893 are positioned to allow the imaging sensor 106 to view the alignment marks provided on the patterning device MA. Note that only one of the two windows 893 and only one of the two imaging sensors 106 are in the Figure 6 The other two windows 894 are positioned to allow the imaging sensor 105 to view the pellicle frame 17 (eg, view the corners of the pellicle frame).

[0218] Figure 10 Arrangement 600 for measuring the position of diaphragm assembly 16 using imaging sensor 105 is shown in greater detail. Figure 10 The arrangement 600 of the devices shown may form Figure 6 A portion of the pellicle frame attachment device 857 is shown. Figure 10 The arrangement 600 of the devices shown shows that Figure 6 These components may form part of the membrane frame attachment device 857 but are not shown here for clarity. Figure 6 It is shown in . It should be noted that Figure 10 The devices in Figure 6 The device is in vertical orientation.

[0219] Arrangement 600 includes: imaging sensor 105; radiation source 602; beam splitter 604; quarter-wave plate 606; window 894 including alignment mark 109; protective window 607; pellicle 19 with pellicle frame 17; and patterning device MA. Imaging sensor 105 may include an array of sensor elements and may be, for example, a camera. Radiation source 602 may be a light-emitting diode (LED). Windows 894 and 607 may be generally transparent. Protective window 607 may protect alignment mark 109 from particulate contamination or other debris.

[0220] exist Figure 10 In the embodiment, the imaging sensor 105, the window 894, the protective window 607, the pellicle 19 and the pattern forming device MA are arranged with Figure 6 894. A beam splitter 604 is disposed between the imaging sensor 105 and the window 894. A quarter-wave plate 606 is disposed between the beam splitter 604 and the window 894. The imaging sensor 105, the beam splitter 604, the quarter-wave plate 606, the window 894, and the protective window 607 can be described as being aligned such that they are all located on an axis and spaced apart in the direction of the axis. The axis is the z-axis. The radiation source 602 is disposed proximate to the beam splitter 604. The radiation source 602 is disposed such that the radiation source 602 and the beam splitter 604 are separated in a direction perpendicular to the axis (such as the y-axis).

[0221] Arrangement 600 may be referred to as an optical measurement system. Figure 10 The optical measurement system illustrated in is operable to measure the position of the pellicle frame 17 relative to the alignment marks 109. The optical measurement system can provide a measurement of the position of the pellicle frame 17 with an accuracy of 5 μm or better. The optical measurement system can be based on a telecentric optical system.

[0222] In use, the radiation source 602 emits an unpolarized beam 608 in a direction perpendicular to the z-axis. The unpolarized beam 608 is incident on the beam splitter 604. The beam splitter 604 splits the unpolarized beam 608 into linearly polarized beams 610 and 612 that propagate in mutually perpendicular directions. The first beam 610 is p-polarized. That is, the first beam 610 is linearly polarized with a polarization direction perpendicular to the plane of incidence (i.e., in the plane of incidence). Figure 10 The first beam 610 propagates in the same direction as the unpolarized beam 608 emitted by the radiation source 602. The second beam 612 is s-polarized. That is, the second beam 612 is linearly polarized with the polarization direction parallel to the plane of incidence (i.e., in the plane of incidence). Figure 10 The second beam 612 propagates parallel to the z-axis toward the quarter-wave plate 606.

[0223] The quarter-wave plate 606 is arranged so that the axis of the quarter-wave plate 606 is aligned at 45 degrees relative to the linear polarization direction of the second beam 612. The second beam 612 that has propagated through the quarter-wave plate 606 becomes a circularly polarized beam 614. The circularly polarized beam 614 can be at least partially transmitted through the window 894, the protective window 607, the pellicle 19 and / or the pellicle frame 17. The circularly polarized beam 614 can be at least partially reflected from the alignment mark 109, the pellicle 19, the pellicle frame 17 and / or the pattern forming device MA. The reflected circularly polarized beam 614 becomes a reflected circularly polarized beam 616 having a circular polarization direction opposite to the circular polarization direction of the circularly polarized beam 614. The reflected circularly polarized beam 616 propagates toward the quarter-wave plate 606.

[0224] The reflected circularly polarized beam 616 that has propagated through the quarter wave plate 606 becomes a linearly polarized beam 618. The linear polarization direction of the linearly polarized beam 618 is rotated 90° relative to the linear polarization direction of the second beam 612. Specifically, the second beam 612 is s-polarized (having a Figure 10 ), and the linearly polarized beam 618 is p-polarized (having a polarization direction in the plane of Figure 10 6). Linearly polarized beam 618 propagates through beam splitter 604. As a result of the p-polarization of linearly polarized beam 618, linearly polarized beam 618 is not split by beam splitter 604. Instead, linearly polarized beam 618 is transmitted through beam splitter 604 as transmitted beam 620. Transmitted beam 620 is then incident on imaging sensor 105.

[0225] Pellicle 19 can be more transmissive to radiation from circularly polarized beam 614 than pellicle frame 17 (which can block substantially all radiation). At least a portion of circularly polarized beam 614 is incident on and reflected by patterning device MA. The edges of pellicle frame 17 may obstruct light reflected from patterning device MA. At least a portion of the radiation reflected by patterning device MA is incident on imaging sensor 105 (as transmitted beam 620) and can have a measured spatial intensity (such as a measured image) at imaging sensor 105 that depends on the position of the edge of pellicle frame 17. Specifically, the difference in light transmission levels through pellicle 19 and pellicle frame 17 can provide spatial contrast in intensity measurements. This spatial contrast can be particularly useful for measuring the position of pellicle assembly 16 and subsequently aligning pellicle assembly 16. For example, the position of pellicle assembly 16 relative to alignment mark 109, which is also imaged by imaging sensor 105, can be measured.

[0226] The quarter wave plate 606 effects a phase shift (between two orthogonal components of the electric field intensity) in the light reflected from the pattern forming device MA (such as the reflected circularly polarized beam 616) as the light propagates through the quarter wave plate 606. This phase shift causes the light reflected from the pattern forming device MA to be maximally transmitted through the beam splitter 604. Maximum transmission of light through the beam splitter 604 may result in a high signal in the intensity measurement performed by the imaging sensor 105. For example, the measurement performed by the imaging sensor 105 may be affected by background light, which may reduce the contrast in the image representing the edge of the pellicle 19 and the pellicle frame 17. However, this background radiation may be unpolarized, so that only a small portion (e.g., half) of this background radiation may reach the imaging sensor. In contrast, the signal radiation (i.e., the portion of the transmitted beam 620 reflected from the pattern forming device MA) is maximally transmitted through the beam splitter 604. Advantageously, this signal light is maximally transmitted through the beam splitter 604 (caused by Figure 10 The arrangement 600 shown may result in high spatial contrast in the measurements performed by the imaging sensor. This may result in high accuracy in the position measurement of the pellicle assembly 16.

[0227] Figure 11 An arrangement 700 for measuring the position of the patterning device MA using the imaging sensor 106 is shown in more detail. Figure 11 The arrangement 700 of the devices shown may form Figure 6 A portion of the pellicle frame attachment device 857 is shown. Figure 11 The arrangement 700 of the devices shown does not Figure 6 These components may form part of the membrane frame attachment device 857 but are not shown here for clarity. Figure 6 It is shown in . It should be noted that Figure 11 The devices in Figure 6 The device is in vertical orientation.

[0228] Arrangement 700 includes: imaging sensor 106; radiation source 702; window 893 including alignment mark 109; and patterning device MA including alignment mark 704. Imaging sensor 106 may include an array of sensor elements and may be, for example, a camera. Radiation source 702 may be an LED. Alignment mark 109 is arranged on window 893 such that alignment mark 109 forms a diffraction grating. Alignment mark 704 is arranged on patterning device MA such that alignment mark 704 forms a diffraction grating.

[0229] exist Figure 11 In the embodiment, the imaging sensor 106, the window 893 and the pattern forming device MA are arranged with Figure 6 The radiation source 702 is arranged in the same manner as shown. The radiation source 702 is arranged so that the radiation source 702 does not obstruct the light path between the imaging sensor 106 and the window 893. The radiation source 702 can be arranged close to the imaging sensor 106.

[0230] Arrangement 700 may be referred to as an optical measurement system. Figure 11 The optical measurement system illustrated in is operable to measure the position of the patterning device MA relative to the alignment mark 109 .

[0231] In use, the radiation source 702 emits a beam 706. The beam 706 propagates toward the window 893. A portion of the beam 706 may be backscattered (e.g., reflected) from the alignment mark 109. Another portion of the beam 706 may be transmitted through the window 893 and then backscattered (e.g., reflected) from the alignment mark 704. Because the alignment marks 109, 704 are arranged to form a reflective diffraction grating, the portion of the beam 706 backscattered from the alignment marks 109, 704 forms a plurality of diffraction orders. Figure 11 Beam 708 is shown, which corresponds to the zeroth order reflection of beam 706 from alignment mark 109 provided on window 893 and from alignment mark 704 provided on patterning device MA. Figure 11 Also shown is beam 710, which corresponds to the first (reflected) diffraction order of beam 706 from alignment mark 109 disposed on window 893 and alignment mark 704 disposed on patterning device MA. First order beam 710 is incident on imaging sensor 106. Imaging sensor 106 is thus operable to measure a signal corresponding to the position of patterning device MA. Zeroth order beam 708 (corresponding to a standard reflection) is not incident on imaging sensor 106.

[0232] The angle at which the beam 706 is backscattered from the alignment marks 109, 704 depends on the angle of incidence between the beam 706 and the alignment marks 109, 704. The angle also depends on the wavelength of the beam 706. The angle also varies with the spacing of the alignment marks 109, 704. Figure 11 In the arrangement 700 shown, the angle of incidence, wavelength of light and spacing of alignment marks 109 , 704 can be selected so that the primary beam 710 is normal to the plane of the patterning device MA. Equivalently, the primary beam can be configured normal to the plane of the pellicle 19 .

[0233] It may be desirable to measure the position of the patterning device MA in the stud attachment apparatus 840 and / or the pellicle frame attachment apparatus 857 (see, e.g., Figure 2 It may also be desirable to measure the position of the patterning device MA when the patterning device MA is used in other situations, such as in the lithographic apparatus LA. Alignment marks 704 may be provided on the patterning device MA so that the position of the patterning device MA can be measured when the patterning device MA is used in other situations, such as in the lithographic apparatus LA.

[0234] Figure 11 The arrangement 700 shown is operable to measure the position of the alignment mark 109 (which is fixed relative to the pellicle frame attachment device 857) and the alignment mark 704 (which is fixed relative to the patterning device MA). Figure 11 The arrangement 700 shown is operable to measure the position of the patterning device MA relative to the pellicle frame attachment device 857. This can be used to align the patterning device MA relative to the pellicle frame attachment device 857. Advantageously, measuring the positions of the alignment marks 109 and the alignment marks 704 is based on measuring diffraction orders of light (as described above) and is performed using the same measurement device (arrangement 700). This may result in an accurate measurement of the position of the patterning device MA. This may result in a more accurate measurement of the position of the patterning device MA than when the position of the patterning device MA is based on measuring the position of an edge of the patterning device MA.

[0235] The arrangements 600, 700 have been described above in the context of the membrane frame attachment device 857. It will be appreciated that the arrangements 600, 700 may be used in other applications. For example, the arrangement 600 may be used to measure the position of the membrane assembly 16 in the membrane attachment device 855 (see Figure 2 As a further example, the arrangement 700 may be used to measure the position of the patterning device MA in the stud attachment apparatus 840 (see Figure 2 ). When the arrangements 600, 700 are used in other applications, the advantages of the arrangements 600, 700 described above will generally apply.

[0236] The alignment marks 109 and 704 may be provided with a sticker. The sticker may be formed from anodized aluminum. The sticker may be black. The sticker may have a generally circular shape. The sticker may include apertures. The sticker may increase the effective size of the alignment marks 109 and 704. The sticker may reduce interference between light reflected from the alignment marks 109 and 704 and any other light. Providing the sticker may increase the contrast of images acquired using the imaging sensors 105 and 106. Specifically, providing the sticker may increase the visibility of the alignment marks 109 and 704 against a light background. Providing the sticker may limit the dispersion of light reflected from the alignment marks 109 and 704. As a result, the alignment marks 109 and 704 measured by the imaging sensors 105 and 106 may appear clearer. This may improve the accuracy of position measurements based on measuring the positions of the alignment marks 109 and 704.

[0237] When using Figure 12 The arrangement 600 shown measures the position of the diaphragm assembly 16 and / or when using Figure 13 The advantages of providing a sticker may be beneficial when the arrangement 700 shown measures the position of the patterning device MA. Alternatively, a coating may be provided to the alignment marks 109, 704, which achieves the same advantages as a sticker.

[0238] Figure 10 and 11 The imaging sensors 105, 106 shown may correspond to Figure 6 Imaging sensors 105, 106 are shown.

[0239] The use of alignment marks to align two entities is well known in the art and will not be described further here.The actuator 111 and the arrangement 600 , 700 may be collectively referred to as a control system 870 .

[0240] Figure 12 The segmented region 862 is depicted in greater detail. The gas outlet (not depicted) may be configured to Figure 12 Gas is supplied to one side of the partition 862 visible in FIG. The gas may be delivered at a pressure higher than the pressure on the opposite side of the partition 862. The partition 862 is also provided with a hole 895 positioned to correspond to the position of the engagement mechanism 50 of the diaphragm assembly 16. One of the holes 895 is located at Figure 13 The hole 895 is sized to allow the pin 1090 and the manipulator pin 1092 to protrude through the hole. The hook member 1091 protrudes from the side of the hole. In other words, the hook member 1091 is fixed to the partition 862 and protrudes from the partition. The pin 1090, the hook member 1091 and the manipulator pin 1092 are also Figure 6 、 12 and 14 are depicted.

[0241] As further mentioned above, the controlled environment above the partitioning region 862 can be maintained at a higher pressure than the pressure below the partitioning region (e.g., by passing a gas above the partitioning region). Figure 12 As will be appreciated, the apertures 895 in the partition 862 are relatively small, thereby limiting the likelihood of contaminants being transferred through the apertures into the controlled environment. This likelihood is further reduced by the higher pressure of the controlled environment relative to the environment in the feed partition 862. The higher pressure ensures that air flows downward through the apertures 895, thereby carrying contaminants away from the diaphragm 19.

[0242] When the pellicle assembly 16 is secured to the patterning device MA, imaging sensors 105, 106 are used to monitor the position of the pellicle assembly 16 relative to the patterning device MA. This occurs after the pellicle assembly 16 is lifted from the intermediate support structure 98 by pins 1090. The position of the pellicle assembly 16 is adjusted using actuator 111. This moves the support structure 101 and, therefore, moves the pellicle assembly 16 relative to the patterning device MA. Operation of the actuator 111 can be manual or can be controlled by an automatic controller. Movement of the support structure 101 can continue until the pellicle assembly 16 is aligned relative to the patterning device MA.

[0243] Once the pellicle assembly 16 has been correctly positioned relative to the patterning device MA, the pin 1090, hook member 1091 and manipulator pin 1092 are used to engage the engagement mechanism 50 to the stud 51 protruding from the patterning device MA.

[0244] The pin 1090, the hook member 1091 and the manipulator pin 1092 are movable relative to each other in a manner such that Figure 14 Schematically illustrated in . As mentioned above, the hook-shaped member 1091 extends from the support structure 101 and is therefore unable to move relative to the support structure. As explained above, the support structure itself 101 can be moved, including in a generally vertical direction (z-direction). The manipulator pin 1092 is movable in a generally vertical direction (z-direction) by the actuator 320. The manipulator pin 1092 is fixed to the actuator 320 and therefore both move together. The pin 1090 supporting the diaphragm frame 17 cannot be actively moved relative to the manipulator pin 1092. The pin 1090 is connected to the actuator 320 via the spring 322. Therefore, upward and downward movement of the actuator 320 will cause corresponding movement of the pin 1090 unless the pin is in contact with the diaphragm frame 17. If the pin 1090 is in contact with the diaphragm frame 17, then further upward movement of the actuator 320 will not result in further upward movement of the pin, but will instead result in compression of the spring 322. Once the spring 322 is compressed, downward movement of the actuator 320 will not cause downward movement of the pin 1090 until the spring 322 has expanded to the relaxed configuration.

[0245] Each manipulator pin 1092 includes a curved surface (e.g., a generally convex surface) at the end of a generally cylindrical body section. The curved surface is at the end of the manipulator pin 1092 that contacts a portion of the engagement mechanism 50 when the pin 1090, hook member 1091, and manipulator pin 1092 are used to engage the engagement mechanism 50 to a stud 51 protruding from the patterning device MA. This process is described below with reference to Figure 17D Further explanation: The curved surface is shaped so that slippage between the manipulator pin 1092 and the portion of the engagement mechanism 50 is minimized.

[0246] Figure 15 and 16 The manner in which the engagement mechanism 50 engages with a protrusion 51 (which may also be referred to as a stud) is schematically depicted. Figure 15 and 16 The engagement mechanism 50 and the protrusion 51 are shown in cross-section as viewed from one side and also as viewed from below. Figure 15 , the engagement arm 80 is pushed away from the cap 66 using a manipulator pin 1092 (not depicted) that pushes against the distal end of the engagement arm 80. Figure 15 It can be seen that there is no contact between the engagement mechanism 50 and the protrusion 51 at this time.

[0247] The engagement mechanisms are moved in the x-direction until the distal heads 53 of the protrusions 51 are positioned over the engagement tabs 81 projecting from the engagement arms 80. This movement is achieved by moving the pellicle frame 17 to which the engagement mechanisms 50 are fixed, and thus moves all engagement mechanisms 50 in unison.

[0248] Once the engagement mechanism 50 is in place, the manipulator pins that push the engagement arms 80 away from the distal head 53 of the protrusion 51 are removed. Since the engagement arms 80 are resilient, they move downward and push against the inner surface of the distal head 53. The engagement tabs 81 thus press the distal head 53 against the cap 66, thereby securing the engagement mechanism 50 to the protrusion 51. This is done in Figure 16 Depicted in.

[0249] It may be desirable to remove the pellicle assembly 16 from the patterning device MA (for example if contamination is detected on the pellicle). This removal may be performed by the pellicle frame attachment apparatus 857. The above sequence is reversed to disconnect the engagement mechanism 50 from the protrusion 51.

[0250] Operation of the pin 1090, hook member 1091 and manipulator pin 1092 may be manual, automatic or semi-automatic.

[0251] Pin 1090, hook member 1091, and manipulator pin 1092 can be formed, for example, from steel. The surfaces of pin 1090, hook member 1091, and manipulator pin 1092 that contact engagement mechanism 50 can be provided with a coating of a material such as PEEK or some other robust material. Alternatively, the contact surfaces can simply be polished surfaces of pin 1090, hook member 1091, and manipulator pin 1092.

[0252] Once the pellicle assembly 16 and patterning device MA have been connected together to form the mask assembly 15, the mask assembly can be placed in the mask assembly transport device 853 for transport to the lithographic apparatus LA (see Figure 2 ).

[0253] Figures 17A to 17H One way in which the engagement mechanism 50 can engage with the protrusion 51 is described in more detail. Figure 17A , the pin 1090 moves in the z direction until it contacts the cap 66 of the engagement mechanism 50. The pin 1090 moves further in the z direction to lift the engagement mechanism 50. Since the engagement mechanism is fixed to the frame 17 (see Figure 3 ), which lifts the entire membrane assembly 16. Pin 1090 is one of four pins 1090 (see Figure 12 ), and the pins 1090 are moved in unison. The diaphragm assembly 16 is thus lifted by the four pins 1090 and supported by those pins 1090. The position of the diaphragm assembly 16 is then adjusted using the actuator 111 (see Figure 6 ) until the pellicle assembly is aligned relative to the pattern forming device MA.

[0254] Reference Figure 17B Then the two hook members move in the z direction until their distal ends are beyond the uppermost surface of the first support arm 82a. Then the hook member 1091 moves in the x direction until the distal ends of the hook members are above the gusset 1089 of the support arm 82a.

[0255] like Figure 17C As depicted, the hook members 1091 are then moved downwardly until they contact the gussets 1089 of the support arms 82a. The pins 1090 and hook members 1091 together clamp the engagement mechanism 50 to allow subsequent operation of the engagement mechanism.

[0256] Reference Figure 17D, the manipulator pin 1092 moves in a generally vertical direction and pushes against the block 54 provided at the distal end of the engagement arm 80. The manipulator pin 1092 pushes the engagement arm 80 upward, thereby expanding the space between the engagement tab 81 and the cap 66. As described above, the surface of each manipulator pin 1092 that contacts the distal end of the engagement arm 80 (particularly the block 54 provided at the distal end of the engagement arm 80) is a curved surface. The curved surface can be a generally convex surface. The curved surface of the manipulator pin 1092 is shaped so that when the manipulator pin 1092 pushes the engagement arm 80 upward, the contact edge between the manipulator pin 1092 and the distal end of the engagement arm 80 smoothly shifts along the curved surface. This minimizes the contact surface area between the manipulator pin 1092 and the block 54 provided at the distal end of the engagement arm 80. Advantageously, this design of the manipulator pin 1092 can ensure that slippage between the manipulator pin 1092 and the block 54 provided at the distal end of the engagement arm 80 is minimized. Due to limitations of the software used to generate the drawings, the engagement arm 80 is Figure 17D There is no upward bend in the

[0257] Reference Figure 17E and 17F The engagement mechanism 50 is then moved in the x-direction until the distal head 53 of the protrusion 51 is above the cap 66 and below the engagement tab 81 .

[0258] As further mentioned above, all engagement mechanisms 50A-D move in unison via movement of pin 1090. In an alternative arrangement, patterning device MA and protrusion 51 can all be moved, rather than moving pellicle frame 17. Typically, only lateral relative movement between the protrusion and the engagement mechanism is required. The direction of lateral movement will depend on the orientation of engagement arm 80 (and can, for example, be in the y-direction rather than the x-direction).

[0259] Reference Figure 17F Once the cap 66 is positioned below the distal head 53 and the engagement tab 81 is above the distal head 53, the manipulator pin 1092 is retracted. The resilience of the engagement arms 80 causes them to return toward their original position, thereby pressing the engagement tab 81 against the distal head 53. The engagement tab 81 pushes the distal head 53 toward the cap 66. This secures the engagement mechanism 50 to the protrusion 51.

[0260] Reference Figure 17G , the hook member 1091 moves upward (in the z direction) and then moves sideways (along the x direction) until the hook member 1091 is positioned away from the gusset 1089 of the support arm 82a. The hook member 1091 is then retracted (moved in the negative z direction).

[0261] Reference Figure 17H , in the final step, the pin 1090 is retracted. Figure 6When the pins 1090 are retracted, the pellicle frame 17 is no longer supported by the pins 1090, but rather the pellicle frame 17 is supported by its connection to the protrusions 51 protruding from the patterning device MA. In other words, the pellicle frame 17 is attached to and supported by the patterning device MA.

[0262] The engagement mechanism 50 is fixed to the protrusion 51 and thus provides a fixed submount 10 for the diaphragm frame (see Figure 3 ). The pellicle frame 17 is thus fixedly attached to the patterning device MA. The pellicle, pellicle frame and patterning device (which may together be referred to as a mask assembly) may then be placed in a transport device 853 for transport to the lithographic apparatus LA (see Figure 2 ).

[0263] Figures 17A to 17H The depicted steps are reversed to detach the engagement mechanism 50 from the protrusion 51 and thereby detach the pellicle frame 17 from the patterning device MA.

[0264] All steps in which the engagement mechanism 50 is secured to the protrusion 51 do not require any sliding movement between the components. In other words, no surfaces are required to rub against each other during the sliding movement. This is advantageous because such friction may easily cause unwanted particle contamination. Figure 17D The depicted step requires mechanical contact of separate components. Consequently, this step may be particularly susceptible to particle contamination. The generally convexly curved surface provided to manipulator pin 1092 reduces the surface area of contact between manipulator pin 1092 and block 54 compared to a manipulator pin without such a curved surface. The generally convexly curved surface provided to manipulator pin 1092 also minimizes the risk of sliding (i.e., friction) between the surface of manipulator pin 1092 and the surface of block 54. Thus, the generation of particulate matter that could lead to particle contamination can be avoided.

[0265] An alternative sequence of steps (not depicted) can be used to attach the engagement mechanism 50 to the protrusion 51. In this alternative sequence, the hook member 1091 is moved into position above the engagement gusset 1089 before the pin is used to raise the diaphragm frame 17. Once the hook member 1091 is in place, the pin 1090 is then moved upward to press against the engagement mechanism 50. The engagement mechanism 50 is thus captured by the hook member 1091 and the pin 1090. The engagement mechanism 50 is then lifted by moving the hook member 1091 and the pin 1090 upward. The same action is performed for the other engagement mechanism 50, and thus the diaphragm assembly 16 is lifted. Using the actuator 111 and the imaging sensors 105, 106 (see Figure 6 ), the pellicle assembly 16 is then aligned relative to the pattern forming device MA. The remaining steps can be as above with reference to Figures 17A to 17H Descriptive.

[0266] Refer to above Figure 17G A safety system is provided in conjunction with the described steps of engaging the engagement mechanism 50 with the protrusion 51. Before the hook member 1091 retracts, it may be possible for the hook member 1091 to not fully disengage from the engagement mechanism 50. For example, if the hook member 1091 does not move sufficiently in the x-direction, as described above, the hook portion of the hook member 1091 and the gusset 1089 of the support arm 82a may overlap. Retraction of the hook member 1091 when it is not fully disengaged from the engagement mechanism 50 may cause damage and / or failure to the diaphragm assembly 16 and / or other components. The actuator 111, which controls the z-position of the support structure 101 (and thus the z-position of the hook member 1091), is operable to detach from the support structure 101. If the support structure 101 exerts a resistance on the actuator 111 that exceeds a threshold resistance (in response to an actuation force applied by the actuator 111 to the support structure 101), the actuator 111 is operable to detach from the support structure 101. This can be described as enabling the support structure 101 to detach from the actuator 111 if movement of the support structure 101 is impeded. Advantageously, the detachable nature of the actuator 111 prevents excessive force from being applied to the engagement mechanism 50. This can be beneficial in preventing damage and / or failure of the diaphragm assembly 16 and / or other components in the event that the hook member 1091 does not fully disengage from the engagement mechanism 50 before the hook member 1091 is retracted.

[0267] As a modification to the above-described safety system, the hook-shaped member 1091 may be provided on an insert disposed within the top surface of the support structure 101. The insert may be detachable. Instead of being able to detach the support structure 101 from the actuator 111 if the movement of the support structure 101 is obstructed, the insert can be detached from the support structure 101 if the movement of the support structure 101 is obstructed. The advantages of the above-described safety system can be applied to this modification of the safety system.

[0268] Features from the two variants of the described security system can be used in isolation. Features from the two variants of the described security system can be used in combination with each other. Further, variants of the described security system can be provided that achieve substantially the same security features.

[0269] An embodiment of the stud attachment device is now combined with Figures 18 to 20 describe.

[0270] Figure 18 A stud attachment device 840 according to an embodiment of the present invention is schematically depicted in cross section. Figure 6 The depicted membrane frame attachment 857 device has similarities. Portions of the stud attachment device 840 may correspond to portions of those other devices.

[0271] The stud attachment apparatus 840 includes a support structure 101 and a stud manipulator 1100 configured to vertically move protrusions 51 (which may also be referred to as studs) so that they contact the patterning device MA. Windows 107, 108 are provided in the support structure 101, and imaging sensors 105, 106 (e.g., cameras) are positioned to view through the windows 107, 108 toward the patterning device MA. Figure 18 The imaging sensors 105, 106 shown may correspond to Figure 10 and 11 106. An imaging sensor 105, 106 is shown. Alignment marks 109 are provided on windows 107, 108 and can be used to align the support structure 101 relative to the pattern forming device. An actuator 111 is provided to move the support structure 101, thereby moving the studs 51 held by the support structure 101. The actuator 111 is capable of moving the support structure in the x, y and z directions, and is also capable of rotating the support structure around the z direction. The actuator 111 can be automatic, manual or semi-automatic (i.e., partially automatic and partially manual). The stud attachment device 840 also includes an additional support structure 97, which is configured to support the pattern forming device MA. The additional support structure can be fixed and is referred to herein as the fixed support structure 97.

[0272] The base of each stud 51 can be prepared with a preparation liquid. The preparation liquid can be isopropyl alcohol (or another alcohol), acetone or ultrapure water. The preparation liquid can be a mixture of one of these substances and softened water. The preparation liquid can be applied to the base of each stud 51 using a swab (such as a micro swab). After the studs are produced and cleaned, a foil (such as a plastic foil) can be applied to the base of each stud 51. Instead of or in addition to preparing the base of each stud 51 with a preparation liquid, the application of the foil can be performed. Preparing the stud 51 with a preparation liquid can remove contaminants from the base of the stud 51. Applying the foil to the stud 51 can prevent new contaminants from being deposited on the base of the stud 51. When the stud 51 is to be attached to the pattern forming device MA (for example, immediately before the stud 51 is attached to the pattern forming device MA), the foil can be removed.

[0273] Glue can then be provided on the base of each stud 51 while the stud is held by a stud manipulator 1100 that forms part of the support structure 101. The glue can be provided by a glue dispenser. The glue dispenser can form part of the stud attachment device 840. It will be appreciated that the glue can be provided in any known manner. The amount of glue dispensed can be controlled by selecting the pressure and pulse time of the glue dispenser. The amount of glue dispensed can be controlled using volumetric dispensing. Volumetric dispensing may be useful for accurately controlling the glue because the viscosity of the glue may vary as it is dispensed.

[0274] The pattern forming device MA is then placed on the fixed support structure 97 so that the pattern forming device MA is positioned a few millimeters above the support structure 101. The actuator 111 is used to move the support structure 101 until the alignment marks 109 provided in the windows 107, 108 are aligned with the alignment marks provided on the pattern forming device MA. The studs 51 are held by the stud manipulator 1100 and have a fixed position in the x and y directions relative to the support structure 101. The spacing between the studs 51 (in fact, there can be four) is a fixed predetermined spacing. The spacing between the studs 51 corresponds to the spacing provided on the pellicle frame 17 (see Figure 3 ) between the engagement mechanisms 50A to 50D on the diaphragm frame 17 to be attached to the pattern forming device MA.

[0275] Once the support structure 101 has been correctly positioned relative to the patterning device MA, the support structure 101 is moved upward and closer to the patterning device MA. The stud manipulator 1100 is then used to move the stud 51 upward from a position where the base of the stud 51 does not contact the patterning device MA to a position where the base of the stud 51 presses against the patterning device MA. A heater can then be used to heat the stud 51 to promote the curing of the glue at the interface between the base of the stud 51 and the patterning device MA.

[0276] The points where the patterning device MA contacts the stud attachment apparatus 840 may be provided with a coating of PEEK or some other robust material.Similarly, the points where the patterning device MA contacts the housing 879 may be provided with a coating of PEEK or some other robust material.

[0277] A portion of the stud attachment device 840 is located at Figure 1921 ). The stud manipulator 1100 is depicted together with the stud 51 and the pattern forming device MA (e.g., a mask). A partition 842 is also depicted, which separates the environment in which the pattern forming device is provided from the environment in which the stud manipulator 1100 is provided. The stud manipulator 1100 includes a cup 1102, the dimensions of which are designed to accommodate the stud 51 (which may also be referred to as a protrusion) so that the bottom surface (i.e., the base) of the stud 51 is outward from the cup 1102. The stud 51 can be held in place in the cup 1102 by gravity. Alternatively, the stud 51 can be held in place in the cup 1102 using a vacuum mechanism (not shown in FIG. 21 ). The vacuum mechanism can temporarily hold the stud 51 fixedly in the cup 1102. The cup 1102 can be formed, for example, of PEEK or some other robust material. The cup 1102 is held in a manipulator head 1104 which in turn is supported on a manipulator body 1106. A spring 1108 is received against a flange 1109 provided on the manipulator body and biases the manipulator head 1104 and the stud 51 upwards. Alignment of the stud 51 relative to the mask is performed using Figure 18 The imaging sensors 105, 106 and actuator 111 are shown. When the actuator has aligned the stud 51 with the patterning device MA, the stud manipulator 1100 moves upward to press the stud 51 against the patterning device MA. The stud manipulators 1100 are moved upward by an actuator (not shown) that simultaneously moves all four stud manipulators 1100 upward. When the stud manipulators 1100 press the stud 51 against the patterning device MA, the spring 1108 is compressed. The spring 1108 partially determines the force with which the stud 51 is pressed against the patterning device MA. A weaker spring will reduce the force with which the stud 51 is pressed against the patterning device, while a stronger spring will increase the force with which the stud 51 is pressed against the patterning device MA. Thus, by selecting a spring 1108 with a desired strength, the force with which the stud 51 is pressed against the patterning device MA can be selected (at least in part). The spring 1108 may, for example, be preloaded with a force that pushes upward the stud operator 1100 and the stud 51. The preloaded force may, for example, be less than 5N.

[0278] The stud manipulator 1100 pushes the stud 51 toward the patterning device MA, thereby allowing the stud 51 to be fixed to the mask. As mentioned above, the stud 51 can be provided with glue or adhesive on its base, and the stud manipulator 1100 can press the stud 51 against the patterning device MA until the glue or adhesive has hardened. Once this has occurred, the stud manipulator 1100 can be removed from the patterning device MA (and / or the patterning device MA can be removed from the stud manipulator 1100).

[0279] In an embodiment, the stud manipulator 1100 may include a heater 1111 configured to heat the stud 51. The heater 1111 may be in the form of an electric heater (e.g., a resistive electric heater). When the stud 51 is held on the patterning device MA, the heater 1111 is used to heat the stud 51. The localized heating of the stud 51 provided by the heater 1111 is advantageous because it promotes the curing of the glue or adhesive. This increases the throughput of the stud attachment device 840. The curing provided by heating the stud 51 can be pre-curing, or it can be full curing. In the case where pre-curing is used, the patterning device MA and the stud 51 can be transferred to an oven for curing. In the case where heating the stud 51 provides full curing, there is no need to transfer the patterning device MA and the stud 51 to an oven. This is advantageous because an oven can be a source of contaminating particles.

[0280] In an embodiment, the stud manipulator 1100 may include an actuator (not depicted) operable to press the stud 51 against the patterning device MA (in addition to or in place of the spring 1108). Once the stud has been secured to the patterning device MA, the actuator may additionally move the cup 1102 away from the stud 51.

[0281] The seal 1112 extends around the periphery of the manipulator head 1104. The seal 1112 is annular in shape. However, the seal can have any suitable shape. The seal 1112 is formed of an elastic material (e.g., PEEK) and protrudes above the partition 842 and above the stud 51. Therefore, when the stud 51 is pressed against the patterning device MA, the seal 1112 is pushed downward. The elastic nature of the seal 1112 means that the seal presses against the patterning device MA and thereby forms a seal against the patterning device MA. This seals the portion of the patterning device MA within the perimeter of the seal 1112 and isolates it from the portion of the patterning device MA outside the perimeter of the seal 1112.

[0282] Gas extraction channels 1114 are provided in the manipulator head 1104, extending away from the outer surface of the manipulator head 1104. Additional gas extraction routes are provided by an annular space 1115 surrounding the manipulator head 1104. Gas delivery channels 1118 are provided on one side of the seal 1112 and allow gas to be delivered to the area of the patterning device MA located within the seal 1112. This is provided by Figure 19The arrows in are schematically depicted. Gas is extracted via gas extraction channels 1114 in the manipulator head 1104 and an annular space 1115 around the manipulator head 1104. The gas extraction channels 1114 are distributed around the manipulator head 1104. A gas flow is provided to transport contaminants out of the gas extraction channels 1114 and the annular space 1115, thereby preventing these contaminants from adhering to the surface of the pattern forming device MA. The contamination may be, for example, particles of glue provided on the studs 51 or chemical vapors from the glue. Chemical vapors are particularly likely to be generated when the glue is heated for curing. Using a gas flow to remove contamination is advantageous because, as explained elsewhere, particles or other contamination on the surface of the pattern forming device MA may cause errors in the pattern projected onto the substrate by the lithographic equipment. For example, the gas may be air.

[0283] Figure 20 An alternative embodiment of a stud attachment device 843 is shown. Figure 20 The stud attachment device 843 is shown with Figure 19 The stud attachment devices 840 shown share many features. Shared features have common reference numerals. For clarity, only a subset of the components of the stud attachment device 843 are shown in FIG. Figure 20 It will be appreciated that the stud attachment device 843 may suitably include Figure 19 Any of the above features of the illustrated stud attachment device 840. The stud attachment device 843 includes Figure 19 The stud attachment device 843 includes two leaf springs 1110. The two leaf springs 1110 connect the manipulator body 1106 to the support structure 101.

[0284] In use, the two leaf springs 1110 provide a defined, generally fixed position of the stud manipulator 1100 head (and subsequently the stud 51) in the xy plane. The two leaf springs 1110 allow some relative movement (in the z direction) between the stud manipulator 1100 body and the support structure 101 (e.g. when the base of the stud 51 contacts the patterning device MA). Thus, when the stud attachment device 843 is pressed down in z, the manipulator head 1104 (via the kinematic mount 1130) and portion 1116 (see FIG. Figure 19 ) is lost.

[0285] Advantageously, each leaf spring 1110 is sized so that movement of the stud manipulator 1100 (relative to the support structure 101) in the z-direction is permissible, while movement in other directions is negligible. Furthermore, by using multiple leaf springs 1110 (e.g., two) rather than a single leaf spring, rotation of the stud manipulator 1100 (and therefore the stud 51) in the xz plane Rxz is negligible. Figure 20The arrangement of the leaf springs 1110 in the stud attachment device 843 shown ensures that the rotation of the stud manipulator 1100 (and therefore the stud 51) in all three axes and the translation in the xy plane are negligible. Therefore, the multiple leaf springs 1110 of the stud attachment device 843 provide an advantage over the springs 1108 of the stud attachment device 840 in accurately positioning the stud 51 relative to the patterning device MA.

[0286] References in this document to a mask may be interpreted as references to a patterning device (a mask is an example of a patterning device), and the terms may be used interchangeably.

[0287] References to glue in this document may be interpreted as references to adhesive, and the terms may be used interchangeably.

[0288] Glue has been referenced above in the context of pellicle attachment devices, such as pellicle attachment device 855. Specifically, glue can be used to attach frame 17 to pellicle 19, and additionally or alternatively, glue can be used to attach engagement mechanisms 50A to 50D (specifically ramp portions 49A to 49D) to frame 17. Glue has also been referenced above in the context of stud attachment devices, such as stud attachment devices 840 and 843. Specifically, glue can be used to attach stud 51 to patterning device MA.

[0289] Many known types of glue may be susceptible to outgassing in the environment within an EUV lithography apparatus (which may be under vacuum conditions and in which EUV radiation and / or hydrogen plasma may be present). Therefore, in the construction of the pellicle assembly and / or mask assembly, it may be desirable to select a glue that does not outgas (or does not significantly outgas under such conditions). In practice, this may limit the list of glues that are suitable for attaching the frame 17 to the pellicle 19 or attaching the studs 51 to the patterning device MA. It is known to use epoxy glue in pellicle attachment apparatuses (for attaching the frame 17 to the pellicle 19) and in stud attachment apparatuses (for attaching the studs 51 to the patterning device MA). However, there are disadvantages to using epoxy glue for the above-mentioned purposes.

[0290] According to an embodiment of the present invention, it is recommended to use poly(methyl methacrylate)-based glue, also known as PMMA glue. Specifically, it is recommended to use PMMA glue in the pellicle attachment device (for attaching the frame 17 to the pellicle 19 and / or for attaching the joining mechanisms 50A to 50D to the frame 17) and the stud attachment device (for attaching the stud 51 to the pattern forming device MA or for directly attaching the frame 17 of the pellicle assembly 16 to the pattern forming device MA).

[0291] This PMMA glue typically includes two components that, when in contact with each other, initiate the curing process of the PMMA glue. These two components can be described as a accelerator and an initiator. Each of the accelerator and the initiator can be provided in a resin. Alternatively, the accelerator and / or the initiator can be provided in a substance that is not a resin. The viscosity of the substance comprising the accelerator can be higher or lower than that of the substance comprising the initiator. It should be understood that, as used herein, "resin" can refer to any substance to which the components of the PMMA glue are provided. Figure 21A and 21B Schematically depicted are examples of two processes for attaching two surfaces to each other using PMMA glue.

[0292] exist Figure 21A In the embodiment, the surface of the first body B1 is provided with a resin containing an accelerator RA, and the surface of the second body B2 is provided with a resin containing an initiator RI. Figure 21A The surface on the second body B2 is then moved relative to the surface on the first body B1 (as indicated by the arrows) so that the resin containing the initiator RI comes into contact with the resin containing the accelerator RA. Figure 21A The contact between the initiator and the accelerator triggers the curing process of the PMMA glue, thereby attaching the surface of the first body B1 to the surface of the second body B2 by means of the cured PMMA glue G'.

[0293] exist Figure 21B In the embodiment, the surface of the first body B1 is provided with: a plurality of rows of resin containing accelerator RI; and a plurality of rows of resin containing initiator RI. The rows are arranged so that the accelerator rows RA and the initiator rows RI alternate. Figure 21A Then, the surface on the second body B2 moves relative to the surface on the first body B1 (as indicated by the arrows) so that the resin rows on the surface on the first body B1 are compressed by the surface on the second body B2. Figure 21B This compression of the resin rows RA, RI brings the initiator into contact with the accelerator, thereby mixing the initiator and accelerator, thereby initiating the curing process of the PMMA glue and attaching the surface of the first body B1 to the surface of the second body B2 with the help of the cured PMMA glue G'.

[0294] It is to be understood that when the surface on the first body B1 and the surface on the second body B2 are brought into contact with each other as described above, the surface on the first body B1 may be moved and the surface on the second body B2 may remain stationary, the surface on the first body B1 may remain stationary and the surface on the second body B2 may be moved, or both surfaces may be moved.

[0295] The surface on the first body B1 may correspond to the surface of the pellicle frame 17, and the surface on the second body B2 may correspond to the surface of the pellicle 19. Alternatively, the surface on the first body B1 may correspond to the surface of the pellicle frame 17, and the surface on the second body B2 may correspond to the surface of the joining mechanisms 50A to 50D. Alternatively, the surface on the first body B1 may correspond to the surface of the stud 51 (e.g., the base surface of the stud 51), and the surface on the second body B2 may correspond to the surface of the pattern forming device MA. Attaching any first surface to any second surface may be done in a Figure 21A 、 Figure 21B or any variation thereof using PMMA glue.

[0296] The curing process of the PMMA glue takes several minutes to complete. This is a significantly shorter curing process than the curing process of known epoxy adhesives used in known pellicle attachment devices and known bolt attachment devices, which typically takes several hours. Therefore, advantageously, using PMMA glue according to one aspect of the present invention to attach the pellicle frame 17 to the pellicle 19 results in a significantly shorter time required to produce the pellicle assembly 16 (compared to using known epoxy glue). Similarly, using PMMA glue to attach the joining mechanisms 50A to 50D to the frame 17 results in a significantly shorter time required to produce the pellicle assembly 16 (compared to using known epoxy glue). Further, advantageously, using PMMA glue to attach the studs 51 to the pattern forming device MA requires significantly less time (compared to using known epoxy glue). This brings associated advantages for high-volume manufacturing.

[0297] Since PMMA glue is typically provided as a resin containing an initiator (RI) and a resin containing an accelerator (RA), PMMA glue can be described as being provided as more than one component.

[0298] It is to be understood that all references in this document to glue, particularly to glue used in film attachment devices (such as film attachment device 855) and stud attachment devices (such as stud attachment devices 840, 843), can be considered to refer to PMMA glue. It is also to be understood that all references in this document to surfaces being attached or bonded to each other using glue, etc., can be considered to refer to glue used in connection with the stud attachment devices 840, 843. Figure 21A and 21B The depicted method affixes or bonds surfaces to each other (although this is not limiting and other methods may be used).

[0299] It may be desirable to remove glue from a surface. For example, it may be desirable to remove both the stud 51 and the glue from the patterning device MA. PMMA glue is generally more flexible than epoxy glue. PMMA glue can be removed from a surface (e.g., from the surface of the patterning device MA) more easily than epoxy glue. Thus, advantageously, once the stud 51 is removed, using PMMA glue (compared to using known epoxy glues) to attach the stud 51 to the patterning device MA results in an easier stud removal procedure and patterning device cleaning procedure.

[0300] The pellicle attachment device (such as the pellicle attachment device 855) and / or the stud attachment device (such as the stud attachment device 840, 843) may include a heater. The heater can be used to heat the known epoxy glue to promote the curing of the known epoxy glue. The component provided with the known epoxy glue can be placed in an oven that heats the known epoxy glue to promote the curing of the known epoxy glue. Advantageously, no heating is required to promote the curing of the PMMA glue. This results in a simpler manufacturing procedure, which may also reduce the risk of defects and damage to manufactured products (such as the pellicle assembly 16 or the pattern forming device MA provided with the studs 51).

[0301] The use of PMMA glue allows an alternative design of the mask assembly 15' to be formed. This alternative design of the mask assembly 15' provides several advantages over the mask assembly 15. This alternative design of the mask assembly is described below with reference to Figure 22B Description, and with Figure 22A The mask assembly 15 is depicted for comparison.

[0302] Figure 22A Shown above using reference Figure 2 The apparatus and method described herein assemble a portion of the mask assembly 15. The studs 51 are attached to the patterning device MA using a known epoxy glue G (only one stud 51 is attached to the patterning device MA). Figure 22A 17). It may be necessary to apply a known epoxy glue G in a layer approximately 50 μm high (in the z direction). The pellicle assembly 16 comprises a pellicle 19 attached to a pellicle frame 17. The bonding mechanism 50 protrudes from the pellicle frame 17 (only one bonding mechanism 50 is present). Figure 22A Each engaging mechanism 50 engages with a corresponding stud 51 to form the mask assembly 15.

[0303] Figure 22B A portion of an alternative design for a mask assembly 15' is shown. A pellicle assembly 16' includes a pellicle 19 attached to a pellicle frame 17. Pellicle frame 17 is directly attached to patterning device MA using PMMA glue G'. PMMA glue G' can be applied around the entire perimeter of pellicle frame 17. Pellicle assembly 16' is thereby attached to patterning device MA, thereby forming mask assembly 15'.

[0304] Any glue can be spatially deformed when the glue is cured. PMMA glue G' is relatively elastic (compared to epoxy glue G). Furthermore, PMMA glue G' can be applied to a layer that is thinner (smaller in the x-direction) and higher (larger in the z-direction) than the layer to which epoxy glue G is applied. Due to the curing of PMMA glue G', the elasticity of PMMA glue G' and the size to which PMMA glue G' can be applied result in low deformation of the pattern forming device MA. In contrast, if the pellicle frame 17 is directly attached to the pattern forming device MA (such as using a known epoxy glue) Figure 22B If the epoxy glue is not used as shown, the deformation of the patterning device MA due to the curing of the epoxy glue will be greater, resulting in errors in the pattern projected onto the substrate by the lithographic apparatus. Therefore, the use of PMMA glue G' allows the production of mask assembly 15', which overcomes the problems associated with the use of known epoxy glues.

[0305] The mask assembly 15' enabled by the use of PMMA glue G' is advantageous for several reasons, as described below.

[0306] The mask assembly 15' can provide an airtight space between the pellicle assembly 16' and the patterning device MA (see Figure 22B ). The mask assembly 15' can thus be described as a 'closed frame' system. Advantageously, this can prevent contaminating particles from: adhering to the side of the patterning device MA facing the pellicle 19; adhering to the side of the pellicle 19 facing the patterning device MA; and / or being disposed in the space between the pellicle 19 and the patterning device MA. This can prevent such particles from causing errors in the pattern applied to the substrate by the lithographic apparatus.

[0307] Mask assembly 15'( Figure 22B ) includes a mask assembly 15 ( Figure 22A ) Fewer parts. Specifically, the mask assembly 15 includes a coupling mechanism 50 protruding from the diaphragm frame 17 and studs 51. Such coupling mechanism 50 and studs 51 are not required in the mask assembly 15'. Advantageously, this may result in a simpler manufacturing process for the mask assembly 15' (compared to the mask assembly 15). Further, the smaller number of parts required and the simpler manufacturing process may result in a lower manufacturing cost for the mask assembly 15' (compared to the mask assembly 15).

[0308] Reference Figure 22A , epoxy glue G is provided on the pattern forming device MA below each stud 51. Figure 22B , PMMA glue G' is provided on the pattern forming device MA so that the PMMA glue G' is provided between the pellicle frames 17 around the entire perimeter of the pellicle frames 17 and is in contact with the pellicle frames 17. Figure 22A) is attached to all studs 51 in the total area of the patterning device MA, in the mask assembly 15 '( Figure 22B ) is attached to the pellicle frame 17 typically has a much larger area. That is, the mask assembly 15 '( Figure 22B ) has a bonding area greater than that of the pattern forming device MA in the mask assembly 15 ( Figure 22A ) in the bonding area of the patterning device MA. The surface of the patterning device MA may be selectively etched so that the epoxy glue G is provided on a portion of said surface ( Figure 22A ) is etched to increase the adhesion between the epoxy glue G and the pattern forming device MA. However, since the mask assembly 15 '( Figure 22B ) has a bonding area of the pattern forming device MA than the mask assembly 15 ( Figure 22A ) is much larger in the mask assembly 15 ′, so no such etching surface is required in the mask assembly 15 ′. Advantageously, this may reduce the manufacturing time and manufacturing cost of the mask assembly 15 ′ (compared to the mask assembly 15).

[0309] The pellicle may have a shorter lifespan than the patterning device. It may be desirable to replace a pellicle assembly that forms part of a mask assembly. As described above, PMMA adhesive is more easily removable and relatively more resilient than known epoxy adhesives. Advantageously, this can enable pellicle assemblies that form part of mask assembly 15', such as pellicle assembly 16', to be more easily replaced.

[0310] Although embodiments of the present invention may be specifically referenced in this text in the context of lithographic equipment, embodiments of the present invention may be used in other equipment. Embodiments of the present invention may form part of mask inspection equipment, metrology equipment, or any equipment that measures or processes objects such as wafers (or other substrates) or masks (or other patterning devices). These equipment may generally be referred to as lithographic tools. Such lithographic tools may use vacuum conditions or ambient (non-vacuum) conditions.

[0311] The term "EUV radiation" may be taken to encompass electromagnetic radiation having a wavelength in the range 4 to 20 nm, for example in the range 13 to 14 nm. EUV radiation may have a wavelength less than 10 nm, for example in the range 4 to 10 nm, such as 6.7 nm or 6.8 nm.

[0312] 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. Possible other applications include 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, and the like.

[0313] Although specific embodiments of the present invention have been described above, it will be appreciated that the present invention may be practiced in ways other than those described. The foregoing description is intended to be illustrative rather than restrictive. Therefore, it will be apparent to those skilled in the art that modifications may be made to the described invention without departing from the scope of the claims set forth below.

Claims

1. An object handling device for handling a planar object, the object handling device comprising: two support arms, at least one of the two support arms being movable in a plane relative to the other support arm such that the two support arms are operable to grip and hold an object disposed in the plane; Each of the support arms includes at least one support pad and at least one aligner, wherein the support pad is configured to locally contact the surface of the object and apply a force perpendicular to the plane thereto to support the object, and the aligner is configured to locally contact the surface of the object and apply a force in the plane thereto to align the object.

2. An object handling device for handling a planar object, the object handling device comprising: two support arms, at least one of the two support arms being movable in a plane relative to the other support arm such that the two support arms are operable to grip and hold an object disposed in the plane; Support structure; as well as Damper assembly; The two support arms are connected to the support structure via the damper assembly, and the damper assembly is configured to inhibit movement of the object in a direction perpendicular to a plane of the object when the object is clamped by the support arms.

3. A membrane frame attachment device comprising: a pellicle assembly disposal device configured to dispose of the pellicle assembly; a patterning device handling apparatus configured to handle the patterning device; as well as rails, wherein the pellicle assembly handling apparatus comprises a support arm configured to clamp and hold the pellicle assembly, and the pattern forming device handling apparatus comprises a support arm configured to clamp and hold the pattern forming device, and wherein the pellicle assembly handling apparatus is supported by a first track in the rail and is movable in a first direction relative to the first track in the rail, and wherein the pattern forming device handling apparatus is supported by a second track in the rail and is movable in the same first direction relative to the second track in the rail, and wherein the first track and the second track extend in the same first direction in the rail, and a portion of one of the first track and the second track extends below the other of the first track and the second track. 4 . The pellicle frame attachment device of claim 3 , wherein the pellicle assembly handling device comprises the object handling device of claim 1 .

5. A pellicle frame attachment apparatus according to claim 3 or claim 4, wherein the patterning device handling apparatus comprises an object handling apparatus according to claim 1. 6 . The pellicle frame attachment device according to claim 3 , wherein the pellicle assembly handling device comprises the object handling device according to claim 2 .

7. The pellicle frame attachment apparatus of claim 3 or 4, wherein the patterning device assembly handling apparatus comprises an object handling apparatus according to claim 2.

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