Stud mounting device and stud mounting method

Abstract

To provide an improved tool and method for a mask assembly.SOLUTION: There is provided a tool for a mask assembly suitable for use in a lithographic process. The mask assembly comprises: a patterning device; and a pellicle frame configured to support a pellicle and mounted on the patterning device with a mount. The mount provides a releasably engageable attachment between the patterning device and the pellicle frame.SELECTED DRAWING: Figure 20

Description

Technical Field

[0001] Cross - reference to related applications

[0001] This application claims priority from U.S. Application No. 62 / 080,561, filed on November 17, 2014, and from U.S. Application No. 62 / 108,348, filed on January 27, 2015, and from U.S. Application No. 62 / 110,841, filed on February 2, 2015, and from U.S. Application No. 62 / 126,173, filed on February 27, 2015, and from U.S. Application No. 62 / 149,176, filed on April 17, 2015, and from U.S. Application No. 62 / 183,342, filed on June 23, 2015, and the entire disclosures of all of them are incorporated herein by reference.

[0002]

[0002] The present invention relates to an apparatus. The apparatus can be used in connection with pellicles for lithographic apparatuses.

Background Art

[0003]

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

[0004]

[0004] The wavelength of the radiation used by a lithographic apparatus to project a pattern onto a substrate determines the minimum size of the features that can be formed on that substrate. Using a lithographic apparatus that uses EUV radiation, which is electromagnetic radiation having a wavelength in the range of 4 - 20 nm, smaller features can be formed on a substrate than with conventional lithographic apparatuses (e.g., those that can use electromagnetic radiation with a wavelength of 193 nm).

[0005]

[0005] A patterning device (e.g., a mask) used to impart a pattern to a radiation beam in a lithographic apparatus can form part of a mask assembly. The mask assembly can include a pellicle that protects the patterning device from particle contamination. The pellicle can be supported by a pellicle frame.

[0006]

[0006] It may be desirable to provide an apparatus that prevents or alleviates one or more problems associated with the prior art.

Summary of the Invention

[0007]

[0007] According to a first aspect of the invention, there is provided a pellicle attachment device comprising a support structure configured to support a pellicle frame and a pellicle handling system configured to place a pellicle on the pellicle frame, the device further comprising an actuator configured to provide relative movement between the pellicle frame and the pellicle before the pellicle is placed on the pellicle frame.

[0008]

[0008] The actuator enables accurate positioning of the pellicle relative to the pellicle frame in order to achieve alignment between the pellicle frame and the pellicle before the pellicle is placed on the pellicle frame.

[0009]

[0009] The actuator can be configured to move the support structure, and thus the pellicle frame, relative to the pellicle.

[0010]

[0010] The pellicle handling system can comprise a support arm configured to hold the pellicle.

[0011]

[0011] Each support arm can include a conduit configured to deliver a vacuum to the leg of the arm.

[0012]

[0012] The foot can be dimensioned to receive a portion of the border of the pellicle.

[0013]

[0013] The support arm can extend downward from a connector arm that extends from the frame of the pellicle handling system.

[0014]

[0014] The connector arm can include one or more leaf springs that allow the connector arm to generally move vertically.

[0015]

[0015] The adjustable end stop can project from the pellicle handling system frame and prevent downward movement of the connector arm beyond a predetermined position.

[0016]

[0016] The bellows can extend between the support arm and the pellicle handling system frame, and the bellows connects a conduit within the support arm to a conduit within the frame.

[0017]

[0017] The support structure can include a window positioned such that the pellicle border edge and / or the pellicle frame edge is visible from the opposite side of the support structure.

[0018]

[0018] The imaging sensor can be provided on one side of the window and is configured to look through the window to view the pellicle border edge and / or the pellicle frame edge on the other side of the window.

[0019]

[0019] Alignment marks can be provided on the window.

[0020]

[0020] The pellicle attachment device can further include an arm configured to hold the pellicle on the pellicle frame after placement on the pellicle frame and pressing the pellicle downward, thereby curing glue at the interface between the pellicle and the pellicle frame.

[0021]

[0021] Each arm can be provided with a weight. The downward pressure applied to the pellicle by the arm can be determined by the weight of the weight.

[0022]

[0022] Each arm can include a downwardly extending finger configured to press against the pellicle.

[0023]

[0023] The finger can be movable laterally relative to other portions of the arm.

[0024]

[0024] Each arm can include a portion extending from a support frame and movable generally perpendicular to the support frame.

[0025]

[0025] Each arm can include an end stop that limits movement of the movable portion of the arm relative to the fixed portion of the arm.

[0026]

[0026] According to a second aspect of the present invention, there is provided a pellicle frame mounting device configured to receive a patterning device and a pellicle assembly including a pellicle frame and a pellicle. The pellicle mounting device includes a manipulator configured to operate an engagement mechanism of a submount provided on the pellicle frame. The manipulator projects through an opening or projects from an opening provided within a partition that separates the pellicle assembly received in a controlled environment from other portions of the pellicle frame mounting device.

[0027]

[0027] The partition includes a window positioned such that a pellicle border edge, a pellicle frame edge, and / or an alignment mark on the patterning device is visible from the opposite side of the partition.

[0028]

[0028] The imaging sensor can be provided on one side of the window. The imaging sensor can be configured to look through the window to view the pericle edge, the pericle frame edge, and / or the alignment marks on the patterning device.

[0029]

[0029] Alignment marks can be provided on the window.

[0030]

[0030] The manipulator can include a pin connected to an actuator, and the actuator is generally configured to move the pin in a vertical direction.

[0031]

[0031] The pin can be movable relative to a pair of hook-shaped arms.

[0032]

[0032] The pair of hook-shaped arms can be connectable to an actuator. The actuator can be configured to move the hook-shaped arms generally in a horizontal direction.

[0033]

[0033] The pair of hook-shaped arms can be fixable to a partition, and the actuator is configured to move the partition and the pair of hook-shaped arms integrally.

[0034]

[0034] Additional pins can be provided, and the additional pins can be movable generally in a vertical direction relative to the movable pin.

[0035]

[0035] The additional pins can be elastically biased relative to the movable pin.

[0036]

[0036] The partition can be connected to a support structure or form part of a support structure.

[0037]

[0037] A coating of a robust material can be provided at the end of the manipulator.

[0038]

[0038] The pellicle frame attachment device may include a gas outlet within the controlled environment, and the gas outlet is configured to supply gas at a pressure higher than the gas pressure applied on the opposite side of the partition.

[0039]

[0039] According to a third aspect of the present invention, there is provided a stud attachment device including a support structure configured to hold a patterning device and a stud manipulator configured to bring a stud into contact with the patterning device, the stud manipulator being separated from the patterning device that receives the controlled environment by a partition, the partition including a hole through which the stud can protrude for contacting the patterning device.

[0040]

[0040] The stud manipulator can be one of a plurality of stud manipulators, and the hole within the partition can be one of a plurality of holes.

[0041]

[0041] The stud attachment device can include a gas outlet within the controlled environment, and the gas outlet is configured to supply gas at a pressure higher than the gas pressure applied on the opposite side of the partition.

[0042]

[0042] A seal can be provided around the stud manipulator. The seal can provide a seal against the patterning device to isolate the stud receiving portion of the patterning device from other portions of the patterning device during use.

[0043]

[0043] At least one gas delivery channel and at least one gas extraction channel can be provided, through which a gas flow can be provided between the stud receiving portion of the patterning device.

[0044]

[0044] The seal can be a leak seal.

[0045]

[0045] The stud manipulator can include a heater.

[0046]

[0046] The partition can include a window positioned such that alignment marks on the patterning device are visible from the opposite side of the partition.

[0047]

[0047] The imaging sensor can be provided on one side of the window and is configured to look through the window to view alignment marks on the patterning device.

[0048]

[0048] A kinematic connection can be provided between the stud manipulator and the support structure.

[0049]

[0049] According to a fourth aspect of the present invention, there is provided a stud removal device comprising a support structure configured to hold a patterning device, a stud gripper configured to receive and hold a distal head of a stud protruding from the patterning device, an actuator configured to move the stud gripper relative to the stud and the patterning device, and a heater.

[0050]

[0050] The stud gripper can comprise a pair of flanges with a separation that is wider than the neck of the stud and narrower than the distal head of the stud.

[0051]

[0051] The stud removal device can further comprise a weight connected to the stud gripper and configured to pull the stud gripper downward.

[0052]

[0052] The stud removal device can further comprise a pusher arm that is generally horizontally movable relative to the stud gripper and is configured to push the stud out of the stud gripper after the stud has been removed from the patterning device.

[0053]

[0053] The stud removal device can further include a chute configured to guide the stud pushed out from the stud gripper.

[0054]

[0054] The stud removal device can further include a stud receptacle disposed at the discharge port of the chute.

[0055]

[0055] According to a fifth aspect of the present invention, a pellicle frame attachment device configured to attach a pellicle frame to a patterning device so as to form a mask assembly that receives a patterning device, a pellicle frame, and a pellicle, and the pellicle frame supports a pellicle adjacent to the patterning device; a lighting system configured to receive a mask assembly from the pellicle frame attachment device, support the mask assembly, adjust a radiation beam, and illuminate the mask assembly using the adjusted radiation beam, wherein the patterning device of the mask assembly is configured to impart a pattern to a cross-section of the adjusted radiation beam to form a patterned radiation beam, a substrate constructed to hold a substrate, and a projection system configured to project the patterned radiation beam onto the substrate, a lithography apparatus comprising; A lithography system is provided, comprising: The lithography system further includes a mask assembly transfer device configured to transfer the mask assembly from the pellicle frame attachment device to the lithography apparatus for use within the lithography apparatus.

[0056]

[0056] The pellicle frame attachment device can be configured to attach the pellicle frame to the patterning device within a sealed environment.

[0057]

[0057] The pellicle frame attachment device can be provided with a vacuum pump configured to pump the sealed environment of the pellicle frame attachment device to vacuum process the pressure situation.

[0058]

[0058] The mask assembly transfer device can be configured to transfer the mask assembly from the pellicle frame attachment device to the lithography apparatus within a sealed environment.

[0059]

[0059] The mask assembly transfer device can be provided with a vacuum pump configured to pump the sealed environment of the mask assembly attachment device to vacuum process the pressure situation.

[0060]

[0060] The lithography system can further include an inspection device configured to inspect one or more of the pellicle, the pellicle frame, and the patterning device for at least one of contamination or defects.

[0061]

[0061] The pellicle frame attachment device can be configured to receive a pellicle attached to the pellicle frame and attach the pellicle frame using the pellicle attached to the patterning device.

[0062]

[0062] The illumination system can be configured to adjust the EUV radiation beam.

[0063]

[0063] The pellicle frame attachment device can be configured to receive a pellicle that is substantially transparent to EUV radiation.

[0064] According to a sixth aspect of the present invention, there is provided a pellicle attachment device configured to receive a pellicle and a pellicle frame, attach the pellicle to the pellicle frame to form a pellicle assembly, and seal the pellicle assembly within a sealed packaging suitable for transporting the pellicle assembly within the sealed packaging.

[0065]

[0065] The pellicle attachment device can be configured to attach a pellicle to a pellicle frame within a sealed environment.

[0066]

[0066] The pellicle attachment device can include a vacuum pump configured to pump a sealed environment to vacuum process a pressure situation.

[0067]

[0067] The pellicle attachment device can further include an inspection device configured to inspect one or both of the pellicle and the pellicle frame for at least one of contamination or defects.

[0068]

[0068] According to a seventh aspect of the present invention, there is provided a method of attaching a pellicle to a pellicle frame, the method including using a pellicle frame handling system to place the pellicle frame on a support structure, applying glue to the pellicle frame, using a pellicle handling system to hold the pellicle over the pellicle frame, aligning the pellicle frame and the pellicle, and placing the pellicle on the pellicle frame.

[0069]

[0069] Alignment of the pellicle frame and the pellicle can be achieved by moving a support structure that supports the pellicle frame.

[0070]

[0070] The method can further include using an arm to press the pellicle downward, thereby holding the pellicle on the pellicle frame while the glue cures.

[0071]

[0071] The groups can be provided at spaced locations. The arm can press the pellicle for each spaced location.

[0072]

[0072] According to an eighth aspect of the present invention, a method of attaching a pellicle assembly to a patterning device is provided, the pellicle assembly comprising a pellicle frame and a pellicle, the method comprising placing the pellicle assembly on a first portion of a support structure, placing the patterning device on a second portion of the support structure with the studs of the patterning device facing the pellicle assembly, moving the pellicle assembly after lifting it from the support structure to align it with the patterning device, and using a manipulator to operate an engagement mechanism of a submount provided on the pellicle frame, the manipulator engaging the engagement mechanism with a stud protruding from the patterning device.

[0073]

[0073] The manipulator can comprise a hook-shaped arm and a manipulator pin used to move an engagement arm of each engagement mechanism relative to a support arm of each engagement mechanism to create a space for receiving a distal head of one of the studs.

[0074]

[0074] The hook-shaped arm can hold the support arm of the engagement mechanism while the manipulator pin is pushing the engagement arm of the engagement mechanism upward.

[0075]

[0075] Lifting the pellicle assembly can be performed using additional pins.

[0076] According to a ninth aspect of the present invention, a method of attaching a stud to a patterning device is provided, the method comprising placing the stud within a stud manipulator provided on a support structure, applying glue to the stud, placing the patterning device over the stud with the patterned surface facing downward, and moving the stud manipulator upward to move the stud into contact with the patterning device.

[0077] The method can further comprise heating the stud using a heater within the stud manipulator to cure the glue.

[0078] It is possible to provide a seal around each stud manipulator, and after gas is delivered to the stud manipulator, the gas is removed from the stud manipulator to remove contaminants from near the seal.

[0079] The seal can be a leak seal.

[0080] According to a tenth aspect of the present invention, a method of removing a stud from a patterning device is provided, the method comprising supporting the patterning device using a support while the patterning device is oriented such that the stud projects downward from the patterning device, moving a stud gripper towards the stud to thereby receive and hold the distal head of the stud, heating the stud gripper to thereby heat the stud to melt glue disposed between the stud and the patterning device, and pulling the stud downward using the stud gripper such that the stud separates from the patterning device when the glue melts.

[0081] The stud can be pulled downward by a weight connected to the stud gripper that pulls the stud gripper downward.

[0082]

[0082] The method can further include using a pusher arm to push the stud out of the stud gripper after the stud has been removed from the patterning device.

[0083]

[0083] The method can further include using a chute to guide the stud to the stud receptacle.

[0084]

[0084] It will be understood that one or more of the aspects or features mentioned above or in the following description can be combined with one or more other aspects or features.

[0085]

[0085] Next, embodiments of the present invention will be described by way of example only, with reference to the accompanying schematic drawings.

Brief Description of the Drawings

[0086]

Figure 1

[0086] It is a schematic diagram showing a lithography system including a lithography apparatus and a radiation source.

Figure 2

[0087] It is a schematic diagram showing various apparatuses and a lithography apparatus according to an embodiment of the present invention.

Figure 3

[0088] It is a perspective view showing a mask assembly according to an embodiment of the present invention.

Figure 4

[0089] It is a cross-sectional view showing a part of the mask assembly of FIG. 3.

Figure 5A

[0090] It is a diagram showing an engagement mechanism forming a part of the mask assembly of FIG. 3.

Figure 5B

[0090] It is a diagram showing an engagement mechanism forming a part of the mask assembly of FIG. 3.

Figure 6

[0091] It is a diagram schematically showing a pellicle attachment device according to an embodiment of the present invention.

Figure 7

[0092] A diagram showing the part of the pellicle attachment device in more detail.

Figure 8

[0093] A perspective view showing a handling system according to an embodiment of the present invention.

Figure 9

[0094] A diagram showing a part of the handling system of FIG. 8 in more detail.

Figure 10

[0095] A diagram schematically showing a part of the pellicle attachment device as viewed from above.

Figure 11

[0096] A cross-sectional view showing the arm of the pellicle attachment device.

Figure 12

[0097] A diagram schematically showing a pellicle frame attachment device according to an embodiment of the present invention.

Figure 13

[0098] A perspective view showing a part of the pellicle frame attachment device.

Figure 14

[0099] A diagram showing a part of the pellicle frame attachment device in more detail.

Figure 15

Figure 16

Figure 17

Figure 18A

Figure 18B

Figure 18C

Figure 18D

Figure 18E

Figure 18F

Figure 18G

Figure 18H

Figure 19

Figure 20

Figure 21

Figure 22

Figure 23

Figure 24

Figure 25

Figure 26

Figure 27

Figure 28

Figure 29

Embodiments for Carrying Out the Invention

[0087] [000112] FIG. 1 shows a lithography system including a mask assembly according to an embodiment of the present invention. The lithography system includes 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 includes an illumination system IL, a support structure MT configured to support a mask assembly 15 including 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 (which is patterned by the patterning device MA at this point) onto the substrate W. The substrate W can include a previously formed pattern. In that case, the lithography apparatus aligns the patterned radiation beam B with the pattern previously formed on the substrate W.

[0088] [000113] The radiation source SO, the illumination system IL, and the projection system PS can all be constructed and arranged so as to be isolated from the external environment. A gas at a pressure lower than atmospheric pressure (e.g., hydrogen) can be provided inside the radiation source SO. A vacuum can be provided inside the illumination system IL and / or the projection system PS. A small amount of gas at a pressure significantly lower than atmospheric pressure (e.g., hydrogen) can be provided inside the illumination system IL and / or the projection system PS.

[0089] [000114] The radiation source SO shown in FIG. 1 is a type that can be called a laser-produced plasma (LPP) radiation source. The laser 1 can be, for example, a CO2 laser, and is arranged and configured to deposit energy into a fuel such as tin (Sn) provided from a fuel emitter 3 via a laser beam 2. Although tin is mentioned in the following description, any suitable fuel can be used. The fuel can be, for example, in liquid form and can be, for example, a metal or an alloy. The fuel emitter 3 can be provided with a nozzle configured to direct tin, for example in the form of droplets, along an orbit towards a plasma formation region 4. The laser beam 2 is incident on the tin in the plasma formation region 4. The deposition of laser energy in the tin creates a plasma 7 in the plasma formation region 4. Radiation including EUV radiation is emitted from the plasma 7 during the de-excitation and recombination of the ions of the plasma.

[0090] [000115] The EUV radiation is collected and focused by a near-normal incidence radiation collector 5 (more generally, sometimes called a normal incidence radiation collector). The collector 5 can have a multilayer structure arranged and configured to reflect EUV radiation (for example, EUV radiation having a desired wavelength such as 13.5 nm). The collector 5 can have a keyhole configuration having two elliptical focal points. As discussed below, the first focal point can be the plasma formation region 4, and the second focal point can be an intermediate focal point 6.

[0091] [000116] In another embodiment of the laser-produced plasma (LPP) radiation source, the collector 5 can be a so-called grazing incidence collector configured to receive EUV radiation at a grazing incidence angle and focus the EUV radiation at an intermediate focal point. The grazing incidence collector can be, for example, a nested collector including a plurality of grazing incidence reflectors. The grazing incidence reflectors can be arranged axially symmetrically around the optical axis O.

[0092] [000117] The radiation source SO can include one or more contamination traps (not shown). For example, the contamination trap can be arranged between the plasma formation region 4 and the radiation collector 5. The contamination trap can be, for example, a rotating wheel trap or any other suitable form of contamination trap.

[0093] [000118] The laser 1 can be separated from the radiation source SO. In that case, the laser beam 2 can be passed from the laser 1 to the radiation source SO with the aid of a beam delivery system (not shown) comprising, for example, suitable guiding mirrors and / or beam expanders, and / or other optical devices. The laser 1 and the radiation source SO can both be regarded as a radiation system.

[0094] [000119] The radiation reflected by the collector 5 forms a radiation beam B. The radiation beam B is focused at point 6 to form an image of the plasma formation region 4 and acts as a virtual radiation source for the illumination system IL. The point 6 at which the radiation beam B is focused can be called an intermediate focus. The radiation source SO is arranged such that the intermediate focus 6 is arranged at or near the opening 8 within the enclosure structure 9 of the radiation source.

[0095] [000120] The radiation beam B extends from the radiation source SO into an illumination system IL configured to condition the radiation beam. The illumination system IL can include a facet field mirror device 10 and a facet pupil mirror device 11. Together, the facet field mirror device 10 and the facet pupil mirror device 11 provide a radiation beam B with a desired cross-sectional shape and a desired angular distribution. The radiation beam B is passed 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 position by a pellicle frame 17. The patterning device MA reflects and patterns the radiation beam B. The illumination system IL can include other mirrors or devices in addition to, or instead of, the facet field mirror device 10 and the facet pupil mirror device 11.

[0096] [000121] Following reflection from the patterning device MA, the patterned radiation beam B enters a projection system PS. The projection system includes a plurality of mirrors configured to project the radiation beam B onto a substrate W held by a substrate table WT. The projection system PS can apply a reduction factor to the radiation beam and form an image with features smaller than the corresponding features on the patterning device MA. For example, a reduction factor of 4 can be applied. In FIG. 1, the projection system PS has two mirrors, but the projection system can include any number of mirrors (e.g., six mirrors).

[0097] [000122] The lithographic apparatus can be used, for example, in a scanning mode, during which the support structure (e.g., mask table) MT and the substrate table WT are scanned synchronously (i.e., dynamic exposure) while a pattern imparted to the radiation beam is projected onto the substrate W. 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 and image inversion characteristics of the projection system PS. The radiation beam with a pattern imparted thereto incident on the substrate W can comprise a band of radiation. The band of radiation can be referred to as an exposure slit. During the scanning exposure, the substrate table WT and the support structure MT can be moved such that the exposure slit travels over the exposure field of the substrate W.

[0098] [000123] The radiation source SO and / or the lithographic apparatus shown in FIG. 1 can include components not shown. For example, a spectral filter can be provided within the radiation source SO. The spectral filter can be substantially transmissive for EUV radiation but can be substantially blocking for radiation of other wavelengths such as infrared radiation.

[0099] [000124] In other embodiments of the lithographic apparatus, the radiation source SO can take other forms. For example, in an alternative embodiment, the radiation source SO can include one or more free electron lasers. The one or more free electron lasers can be configured to emit EUV radiation that can be provided to one or more lithographic apparatuses.

[0100] [000125] As briefly described above, the mask assembly 15 includes a pellicle 19 provided adjacent to the patterning device MA. The pellicle 19 is provided in the path of the radiation beam B such that the radiation beam B passes through the pellicle 19 both when the radiation beam B approaches the patterning device MA from the illumination system IL and when it is reflected by the patterning device MA in the direction of the projection system PS. The pellicle 19 comprises a thin film that is substantially transmissive to EUV radiation (although it will absorb a small amount of EUV radiation). As used herein, for an EUV transmissive pellicle or film to be substantially transmissive to EUV radiation means that the pellicle 19 transmits at least 65%, preferably at least 80%, more preferably at least 90% of the EUV radiation. The pellicle 19 serves to protect the patterning device MA from particle contamination.

[0101] [000126] While efforts can be made to maintain a clean environment within the lithographic apparatus LA, particles can still be present within the lithographic apparatus LA. In the absence of the pellicle 19, particles can deposit on the patterning device MA. Particles on the patterning device MA can have an adverse effect on 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 so that particles do not deposit on the patterning device MA.

[0102] [000127] The pellicle 19 is positioned at a sufficient distance from the patterning device MA so that any particles incident on the surface of the pellicle 19 are not within the focal plane of the radiation beam B. 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 can impart a pattern to the radiation beam B. It will be appreciated that if a particle is present within the radiation beam B but not at a position within the focal plane of the radiation beam B (i.e., not at the surface of the patterning device MA), any image of the particle will not be in focus on the surface of the substrate W. In the absence of other considerations, it may be desirable to position the pellicle 19 at a relatively large distance from the patterning device MA. However, in practice, the space available within the lithographic apparatus LA for accommodating the pellicle is limited due to the presence of other components. In some embodiments, the separation between the pellicle 19 and the patterning device MA can be, for example, between approximately 1 mm and 10 mm, such as between 1 mm and 5 mm, more preferably between 2 mm and 2.5 mm.

[0103] [000128] The mask assembly can be prepared for use within the lithographic apparatus by attaching the pellicle to a pellicle frame and attaching the pellicle frame to the patterning device. The mask assembly, comprising the patterning device MA and the pellicle supported adjacent to the patterning device by the pellicle frame, can be prepared remotely from the lithographic apparatus LA and the mask assembly can be transferred to the lithographic apparatus LA for use within the lithographic apparatus LA. For example, the pellicle frame supporting the pellicle can be attached to the patterning device so as to form the mask assembly at the location where the pattern is applied onto the patterning device. The mask assembly can then be transferred to another location where the lithographic apparatus LA is located and the mask assembly can be provided to the lithographic apparatus LA for use within the lithographic apparatus LA.

[0104] [000129] A mask assembly in which a pellicle is held in a fixed position by a pellicle frame is precise, and transporting the mask assembly can pose a risk of damaging the pellicle. Additionally, assembling the mask assembly in an environment separate from the lithography apparatus LA will result in exposing the mask assembly to various pressure situations. For example, the mask assembly can be transported to the lithography apparatus under atmospheric pressure conditions. The mask assembly can then be loaded into the lithography apparatus LA via a load lock that is pumped to vacuum the pressure situation. Changes in the pressure situations to which the mask assembly is exposed can cause pressure differences across the entire pellicle that can bend the pellicle and pose a risk of damaging the pellicle. In an embodiment, the lithography system can include a lithography apparatus LA connected to a pellicle frame attachment device. In that case, a mask assembly comprising a mask and a pellicle can be directly transported from the pellicle frame attachment device to the lithography apparatus while remaining within a controlled environment.

[0105] [000130] Figure 2 is a schematic view of an apparatus suitable for assembling the mask assembly 15 and transporting the mask assembly to the lithographic apparatus LA. Figure 2 shows a pellicle mounting device 855 that can be used to attach the pellicle 19 to the pellicle frame 17, and a pellicle assembly transfer device 881 that can be used to transfer the pellicle assembly. In addition, a stud mounting device 840 is shown that can be used to attach the stud 51 to the patterning device MA. The stud 51 enables the releasable attachment of the pellicle frame 17 (and the pellicle 19) to the patterning device MA. A mask transfer device 880 is also shown that can be used to transfer the mask together with the attached stud. A pellicle frame mounting device 857 is also shown that can be used to attach the pellicle frame 17 (and the pellicle 19) to the patterning device MA, thereby forming the mask assembly 15. A mask assembly transfer device 853 is also shown that can be used to transfer the mask assembly 15 from the pellicle frame mounting device 857 to the lithographic apparatus LA.

[0106] [000131] The pellicle mounting device 855 can be located at a location different from the location where the lithographic apparatus is located. The stud mounting device 840 can be located at a location different from the location where the lithographic apparatus LA is located. Alternatively, either or both of the pellicle mounting device 855 and the stud mounting device 840 can be arranged at the same location as the location where the lithographic apparatus LA is located (for example, a lithography manufacturing facility).

[0107] [000132] The pellicle attachment device 855 receives the pellicle 19, the pellicle frame 17, and an engagement mechanism (not shown). The pellicle 19 and the pellicle frame 17 can be manually placed within the pellicle attachment device 855. The glue is dispensed at an engagement mechanism receiving opening (e.g., a location further described below) within the pellicle frame 17. The dispensing of the glue can be manual or automatic (or partially automatic). After the engagement mechanism and the pellicle frame 17 are aligned with each other (e.g., using an optical alignment device), the engagement mechanism is inserted into an opening within the pellicle frame.

[0108] [000133] The glue is also dispensed onto the pellicle frame 17 (e.g., at spaced locations around the perimeter of the pellicle frame 17). The dispensing of the glue can be manual or automatic (or partially automatic). After an optical alignment system is used to align the pellicle 19 with respect to the pellicle frame 17, the pellicle is pressed against the pellicle frame again.

[0109] [000134] The pellicle 19 is held pressed against the pellicle frame 17 at room temperature for a period sufficient to cure the glue, thereby fixing the pellicle to the pellicle frame. Thereafter, the pressure applied to the pellicle 19 is removed. Then, a curing oven (which can form part of the pellicle attachment device) is used to perform additional curing of the glue at an elevated temperature. This will also cure the glue that attaches the engagement mechanism to the pellicle frame 17. In an alternative approach, some heating can be applied (instead of allowing curing to proceed at room temperature) to cure the glue while the pellicle 19 is pressed against the pellicle frame.

[0110] [000135] Although the use of glue for attaching the pellicle 19 to the pellicle frame 17 has been described above, the pellicle can be attached to the pellicle frame using any suitable type of adhesion (including not using glue).

[0111] [000136] The resulting pellicle assembly 16 is inspected using a particle inspection tool. The particle inspection tool can form part of the pellicle attachment device 855 (or can be a separate tool). The particle inspection tool can be configured to inspect particles disposed on the pellicle 19 and / or the pellicle frame 17. The particle inspection tool can, for example, reject a pellicle assembly having more particles than a given particle threshold. The particle inspection tool can also be used to inspect the pellicle 19 and / or the pellicle frame 17 before the pellicle and the pellicle frame are adhered together.

[0112] [000137] The pellicle attachment device 855 can be configured to seal the pellicle assembly 16 within a pellicle assembly transfer device 881 (sealed box) after inspection. As shown in the figure, the pellicle assembly transfer device 881 can be arranged and configured to hold the pellicle assembly in an orientation where the pellicle 19 is below the pellicle frame 17. Since the transfer device 881 is sealed, the pellicle assembly 16 can be transferred without being contaminated. The pellicle assembly 16 can be transferred to the pellicle frame attachment device 857 within the transfer device 881.

[0113] [000138] The pellicle attachment device 855 can include a clean environment so as to reduce the number of particles inside the sealed environment, thereby reducing the number of particles that can be deposited on the pellicle 19. The pellicle attachment device 855 can be located, for example, at the location where the pellicle is manufactured. In some embodiments, the pellicle 19 can be provided directly from a pellicle manufacturing tool (not shown) where the pellicle 19 is manufactured to the pellicle attachment device 855. The pellicle 19 can be provided from the pellicle manufacturing tool to the pellicle attachment device 855 while maintaining the pellicle 19 inside a clean environment, for example. Thereby, the chance of being contaminated or damaged can be reduced before the pellicle 19 is provided to the pellicle attachment device 855. The clean environment can be, for example, a sealed environment (i.e., completely isolated from the external environment). The sealed environment can be pumped to maintain a vacuum inside the sealed environment.

[0114] [000139] The attachment of the pellicle 19 to the pellicle frame 17 can be controllable to achieve a desired tension within the pellicle 19. For example, the tension within the pellicle 19 can be measured during or after the attachment of the pellicle 19 to the pellicle frame 17, and the tension can be adjusted in response to the measurement to achieve the desired tension within the pellicle 19. The tension within the pellicle 19 can be maintained, for example, by applying an outward force to a component of the pellicle frame 17 so as to stretch the pellicle 19. The tension within the pellicle 19 can be maintained, for example, by using the difference in the coefficient of thermal expansion between the pellicle frame and the pellicle.

[0115] [000140] In an embodiment, the patterning device (which can be referred to as a mask) MA can be provided with protrusions received by an engagement mechanism (such as further described below). The patterning device can receive, for example, four protrusions (referred to herein as studs). As shown in FIG. 2, the stud attachment device 840 can be used to attach the stud 51 to the patterning device MA.

[0116] [000141] The stud 51 and the patterning device MA can be manually placed within the stud attachment device 840. The patterning device MA can be held in a controlled environment 841 separated from the rest of the stud attachment device 840. The separation can be provided by a partition 842 with an opening through which the stud 51 can protrude to contact the patterning device MA. The controlled environment 841 can be held at a higher pressure than the other parts of the stud attachment device 840 (for example, by delivering gas through an outlet within the controlled environment). This suppresses or prevents contaminant particles from passing from the other parts of the stud attachment device into the controlled environment 841.

[0117] [000142] The stud attachment device 840 can include a stud manipulator (not shown), such as a robot or actuator, for accurately positioning the stud. An example of an actuator suitable for placing the stud on the patterning device is a Lorentz actuator (not shown). The stud attachment device 840 can also include a device for automatically providing a given amount of glue or adhesive to the stud surface that is to be attached to the patterning device MA (however, the application of glue or adhesive can also be done manually in advance). Contamination of the mask MA by contaminants from the glue or adhesive is prevented or reduced by the flow of air from the controlled environment above the partition 842 to below the partition (the air flow is caused by the pressure above the partition being higher than the pressure below the partition).

[0118] [000143] The stud attachment device 840 can further include an optical alignment system that aligns the stud with respect to alignment markers present on the reticle for accurately positioning the stud. For example, alignment markers that were conventionally provided on the patterning device MA and used for pattern alignment can also be used for stud alignment.

[0119] [000144] The stud attachment device can include a support structure movable in the X - Y - Z and Rz directions for adjusting the position of the patterning device MA. The position of the support structure holding the patterning device MA can be adjusted manually using coarse and fine mechanical adjustment devices, or using an automated (or semi - automated) actuator, or any other type of device suitable for alignment and positioning coupled to the patterning device table.

[0120] [000145] After the stud 51 and the patterning device MA are aligned, the stud is pressed against the patterning device MA. The stud 51 can be held in a state of being pressed against the patterning device MA at room temperature for a period sufficient to cure the glue, whereby the stud is fixed to the mask. Alternatively, the stud 51 can be heated to accelerate the curing of the glue. Then, a curing oven (which can form part of the stud mounting device 840) can be used to perform additional curing of the glue at a high temperature.

[0121] [000146] The patterning device MA and the stud 51 can be inspected using a particle inspection tool (which can form part of the stud mounting device 840).

[0122] [000147] The stud mounting device 840 seals the patterning device MA and the stud 51 within a patterning device MA transfer device 880 (a sealed box). Since the mask transfer device 880 is sealed, the patterning device MA and the stud 51 can be transferred without the mask being contaminated. The patterning device MA and the stud can be transferred to a pellicle frame mounting device 857 within the transfer device 880.

[0123] [000148] In an embodiment, a mask is provided to the stud mounting device 840 within the sealed box (to reduce the risk of contamination). The box can maintain a sealed state until immediately before the stud 51 is attached to the patterning device MA, thereby minimizing the time during which contamination can progress to the mask.

[0124] [000149] The controlled environment 841 of the stud attachment device 840 can be partially provided by a housing that will later form part of the patterning device MA transfer device 880 (sealed box). The housing can form the walls and roof of the transfer device 880, and the floor of the transfer device is formed by a plate that is fitted after the stud 51 is attached (e.g., immediately afterwards). By using the housing in this way, it can help prevent contamination from impinging on the patterning device MA. The housing can comprise a pod cover. The mask table of the stud attachment device 840 can be configured to receive the housing.

[0125] [000150] Similarly, the pellicle attachment device 855 can also be partially formed by a housing that will later form part of the pellicle assembly transfer device 881.

[0126] [000151] The pellicle assembly 16 within the transfer device 881 and the patterning device MA (and stud 51) within the transfer device 880 are both transferred to the pellicle frame attachment device 857. The pellicle frame attachment device 857 can be provided within a fabrication facility that also provides one or more lithographic apparatuses.

[0127] [000152] The pellicle frame attachment device 857 is configured to attach the pellicle frame 17 of the pellicle assembly 16 to the stud 51 on the patterning device MA so as to form the mask assembly 15. The pellicle frame attachment device 857 can include a controlled environment 860 separated from the rest of the pellicle frame attachment device. The separation can be provided by a partition 862 having an opening through which the manipulator extends (not shown in FIG. 2). The manipulator is operable by a control system 870 (further described below). The controlled environment 860 can be maintained as a clean environment so as to reduce the number of particles inside the controlled environment, thereby reducing the number of particles that can be deposited on the mask assembly 15. The controlled environment 860 can be held at a higher pressure than other parts of the pellicle frame attachment device (e.g., by delivering gas through an outlet within the controlled environment). This suppresses or prevents contaminating particles from passing from other parts of the pellicle frame attachment device 857 into the controlled environment 860.

[0128] [000153] The mask assembly 15 assembled by the pellicle frame attachment device 857 is transferred from the pellicle frame attachment device to the lithography apparatus LA in the mask assembly transfer device 853. The mask assembly transfer device 853 can have a sealed and clean environment inside which the mask assembly 15 is transferred. Thereby, the chance that the mask assembly 15 is contaminated or damaged during the transfer of the mask assembly is reduced. The sealed and clean environment can be pumped to a vacuum, for example.

[0129] [000154] The pellicle frame attachment device 857 can be used to mount, remove, or remount the pellicle assembly 16 with respect to the patterning device. The pellicle frame attachment device 857 can include a manipulator arranged and configured to operate an engagement mechanism of the pellicle frame (as further described below).

[0130] [000155] The patterning device MA can provide, for example, alignment marks. The pellicle frame 17 can be positioned with respect to the alignment marks on the patterning device. By aligning the pellicle frame 17 with respect to the alignment marks on the patterning device, advantageously, the accuracy in positioning the pellicle frame 17 on the patterning device MA can be improved while the pellicle frame 17 is being attached to the patterning device MA.

[0131] [000156] In some embodiments, the patterning device MA can be cleaned within the pellicle frame attachment device 857, for example, to remove particles from the patterning device MA. In other embodiments, the cleaning of the patterning device MA can be performed within a dedicated cleaning tool.

[0132] [000157] The illustrated embodiment shows the pellicle frame being attached to the front portion of the mask, but in other embodiments, the pellicle frame can be attached to other portions of the mask. For example, the pellicle frame can be attached to the side surface of the mask. This can be achieved, for example, using a submount that provides a releasable engagable attachment between the pellicle frame and the side surface of the mask. In an alternative arrangement, the pellicle frame can be attached to the mask via a combination of some attachment location on the side portion of the mask and some attachment location on the front portion of the mask. The attachment can be provided, for example, by a submount that releasably engages the pellicle frame and the mask.

[0133] [000158] In some embodiments, the pellicle frame attachment device 857 can include a particle inspection tool (not shown). The particle inspection tool can be configured to inspect the mask assembly 15 for particles disposed on the mask assembly 15. The particle inspection tool can reject, for example, a mask assembly 15 having a number of particles greater than a given particle threshold.

[0134] [000159] In some embodiments, the pellicle frame attachment device 857 can include a pattern inspection system that inspects the pattern on the patterning device for any defects. The pattern inspection system can inspect the pattern on the patterning device before and / or after the pellicle frame 17 is attached to the patterning device MA.

[0135] [000160] The attachment of the pellicle frame 17 to the patterning device MA can be controlled to achieve a desired tension within the pellicle 19. For example, the tension within the pellicle 19 can be measured during the attachment of the pellicle frame 17 to the patterning device MA, and the tension can be adjusted in response to the measurement to achieve the desired tension within the pellicle 19.

[0136] [000161] The lithographic apparatus LA can, for example, correspond to the lithographic apparatus LA shown in FIG. 1. The lithographic apparatus LA can include components configured to receive the mask assembly 15 from the mask assembly transfer device 853 and load the mask assembly 15 onto the support structure MT of the lithographic apparatus LA. The mask assembly 15 can be illuminated with an adjusted radiation beam B provided by the illumination system IL. The patterning device MA of the mask assembly 15 can impart a pattern to the cross-section of the adjusted radiation beam in order to form a patterned radiation beam. The patterned radiation beam can be projected by the projection system PS onto a substrate W held by the substrate table WT. The adjusted radiation beam can include, for example, EUV radiation. In embodiments where the adjusted radiation beam includes EUV radiation, the pellicle 19 of the mask assembly 15 can be substantially transmissive to EUV radiation.

[0137] [000162] In some embodiments, the pellicle assembly 16 can be attached to the patterning device MA so as to form the mask assembly 15 under a vacuum situation within the pellicle frame attachment device 857. Subsequently, the mask assembly transfer device 853 can transfer the mask assembly 15 to the lithographic apparatus LA under a vacuum situation and hold it within the lithographic apparatus LA under a vacuum situation. Thus, the mask assembly 15 can be exposed to a substantially same pressure situation throughout its assembly within the pellicle frame attachment device 857 and can be used within the lithographic apparatus LA. Advantageously, this reduces any pressure changes to which the mask assembly 15 is exposed and thus reduces any potential pressure differences across the entire pellicle 19.

[0138] [000163] In some embodiments, the patterning device MA and / or the pellicle 19 can be inspected for particles and / or defects within the pellicle frame attachment device 857 while the components are held in a vacuum. Thus, the patterning device MA and / or the pellicle 19 are advantageously inspected under a pressure situation similar to that to which they are exposed during use within the lithographic apparatus LA. This is advantageous because any particles that may deposit on the patterning device MA and / or the pellicle during pumping down to the vacuum situation can be detected within the pellicle frame attachment device 857.

[0139] [000164] In some embodiments, the lithography system LS can further comprise a separate inspection device (not shown) configured to inspect one or more components of the mask assembly 15 for particles and / or defects. The mask assembly 15 can be transferred to the inspection device (e.g., by the mask assembly transfer device 853) after being assembled within the pellicle frame attachment device 857, and before transferring the mask assembly 15 to the lithographic apparatus LA.

[0140] [000165] Embodiments of the invention as described above advantageously enable the mask assembly 15 to be assembled and passed to the lithographic apparatus LA in an automatic (or semi-automatic) process. All of the assembly and transfer of the mask assembly 15 can be performed, for example, within a sealed clean environment that can be pumped down to a vacuum pressure situation. This can reduce the chance that the components of the mask assembly 15 become contaminated or damaged before using the mask assembly 15 within the lithographic apparatus LA.

[0141] [000166] Generally, the service life of the pellicle 19 may be shorter than that of the patterning device MA. Therefore, in order to be able to continue using the patterning device MA, it may be desirable to remove the pellicle assembly 16 from the patterning device MA and replace the pellicle assembly with a new one. The replacement of the pellicle assembly 16 can be carried out, for example, within the pellicle frame mounting device 857. For example, after use in the lithography apparatus LA, the mask assembly 15 can be returned to the pellicle frame mounting device 857 using the mask assembly transfer device 853 for replacement of the pellicle assembly within the pellicle frame mounting device 857. After the pellicle assembly 16 is removed from the patterning device MA, the patterning device MA can be subjected to a cleaning process to remove contaminants from the patterning device MA. Before subjecting the patterning device to the cleaning process, the stud 51 can be removed from the patterning device MA.

[0142] [000167] Note that the patterned side of the patterning device MA is directed downward during the various operations shown in FIG. 2. Maintaining the patterned side of the patterning device MA downward is advantageous in order to reduce the probability of contaminant particles impinging on the pattern. Larger contaminant particles tend to fall downward due to gravity and will impinge on the opposite side of the mask. Smaller contaminant particles are not as affected by gravity, but may instead be affected by other transport physical properties. The apparatus of embodiments of the present invention can include devices intended to address this. For example, the apparatus can include an ionization device for removing static charge, thereby reducing the risk that static electricity will cause particles to adhere to the pellicle.

[0143] [000168] A mask assembly according to an embodiment of the present invention is shown in FIGS. 3-5. In this embodiment, the pellicle frame and the pellicle are suspended with respect to a patterning device (e.g., a mask). The pellicle frame can engage releasably with the patterning device. The releasable engagement is provided by a mount having a plurality of submounts (e.g., 2, 3, 4, or more submounts). The mount enables the pellicle frame (and the pellicle) to be removed from the patterning device in an easy and convenient manner. The removal of the pellicle frame and the pellicle from the patterning device is clean, i.e., it is possible to substantially generate no contaminating particles. When the pellicle frame is removed from the patterning device, the patterning device can be inspected (and, if necessary, cleaned) using an inspection tool. The pellicle frame and the pellicle can be substantially easily reattached to the patterning device or replaced with a new pellicle frame and pellicle.

[0144] [000169] First, referring to FIG. 3, the pellicle 19 is attached to the pellicle frame 17. The pellicle 19 can be adhered to the pellicle frame 17, for example. Four engaging mechanisms 50A to D are provided on the pellicle frame 17. Each of the engaging mechanisms 50A to D is configured to receive a protrusion (which can be called a stud, for example) extending from a patterning device (as will be described below with respect to FIG. 4). Two engaging mechanisms 50A and B are provided on one side of the pellicle frame 17, and two engaging mechanisms 50C and D are provided on the opposite side of the pellicle frame. Other combinations are possible, such as providing an engaging mechanism on each of the four sides of the frame. The engaging mechanisms are provided on the side surface of the pellicle frame 17 that will be oriented in the scanning direction during use in a lithographic apparatus (shown as the y direction in FIG. 3 according to the conventional notation). However, the engaging mechanisms can also be provided on the side surface of the pellicle frame 17 that will be oriented perpendicular to the scanning direction during use in a lithographic apparatus (shown as the x direction in FIG. 3 according to the conventional notation).

[0145] [000170] The protrusions received by the engaging mechanisms 50A to D can be arranged on the front surface of the patterning device. Additionally or alternatively, the protrusions can be arranged on the side surface of the patterning device. The protrusions can extend upward from the side surface of the patterning device. In such an arrangement, each of the protrusions can have a flat outer surface to facilitate reliable adhesion to the side surface of the patterning device.

[0146] [000171] Figure 3 shows four engagement mechanisms 50A - D fixed to the pellicle frame 17. Two sub - mounts 50A, D are configured to allow movement in the y - direction (i.e., provide flexibility or compliance in the y - direction). Two sub - mounts 50B, C are configured to allow movement in the x - direction (i.e., provide flexibility or compliance in the x - direction). However, since all four sub - mounts 50A - D are configured such that engagement can be achieved between the sub - mount and a protrusion (not shown) via movement in the y - direction, as can be seen in the figure, all four sub - mounts include engagement arms 80 that extend in the y - direction. A possible drawback of this configuration is that during a sudden deceleration during y - direction scanning movement, the engagement mechanisms 50A - D attached to the protrusion may slide off (due to the inertia of the pellicle frame 17). This can occur, for example, when there is a "crash" of the mask support structure MT (see Figure 1). In an alternative arrangement, all four sub - mounts can include engagement arms that extend in the x - direction (i.e., the non - scanning direction). Having engagement arms that all extend in the non - scanning direction is advantageous because this avoids the possibility that a sudden y - direction deceleration causes separation of the engagement mechanism. In general, the engagement arms of each sub - mount can all extend in substantially the same direction.

[0147] [000172] To enable movement / flexibility in the x-direction, the arm 62 that supports the locking members of the two submounts 50B and C extends in the y-direction. Since these arms are elastically flexible in the x-direction, they provide movement / flexibility in the x-direction. Accordingly, the engaging arms 80 of the two submounts 50B and C generally extend parallel to the arm 62 of that submount. To enable movement / flexibility in the y-direction, the arm 62 that supports the locking members of the other two submounts 50A and D extends in the x-direction. Since these arms are elastically flexible in the y-direction, they provide movement / flexibility in the y-direction. Accordingly, the engaging arms 80 of the two submounts 50A and D generally extend perpendicular to the arm 62 of that submount. The movement / flexibility provided by the submounts 50A - D enables the bending of the pellicle frame 17 with respect to the patterning device MA as needed when a temperature change occurs. This is advantageous because potentially damaging thermal stresses generated within the pellicle frame 17 are avoided.

[0148] [000173] The submounts 50A - D are shown to include tabs 56 having a configuration different from the tabs 56 shown in FIG. 5. However, the tabs provide the same function of facilitating the engagement between the submounts 50A - D and the pellicle frame 17. Any suitable configuration of the tabs can be used.

[0149] [000174] FIG. 4 shows a cross-section of one engaging mechanism 50B in conjunction with the protrusion 51 protruding from the patterning device MA. The protrusion 51, also called a stud, can be attached to the patterning device MA, for example, by glue bonding or by other bonding means (such as optical contact, magnetism, or van der Waals forces). The engaging mechanism 50B and the protrusion 51 together form the submount 10. The protrusion 51 includes a distal head 53 disposed on a shaft 55 extending from a base 57. The base 57 is fixed to the patterning device MA, for example, by using glue. The shaft 55 and the distal head 53 can be cylindrical or have any other suitable cross-sectional shape.

[0150] [000175] The submount 10 suspends the pellicle frame 17 with respect to the patterning device MA such that a gap G (which can be regarded as a slit) exists between the pellicle frame and the patterning device. The gap G can be maintained by the engagement between the cap 66 of the engagement mechanism 50B and the distal head 53 of the protrusion 51 (or by some other motion-limiting component). The gap G can be made wide enough to enable pressure equalization between the external environment and the space between the pellicle and the patterning device. The gap G can also be made narrow enough to impose desirable constraints on potential routes of contaminant particles from the external environment to the space between the pellicle and the patterning device. The gap G can be, for example, at least 100 microns in order to enable pressure equalization between the external environment and the space between the pellicle and the patterning device. The gap G can be less than 500 microns, more preferably less than 300 microns. The gap G can be, for example, between 200 and 300 microns.

[0151] [000176] FIG. 5 shows the submount 10 of FIG. 4 in more detail. The pellicle frame attached to the engagement mechanism 50B is not shown in FIG. 5. Similarly, the patterning device with the protrusion 51 protruding is not shown in FIG. 5. FIG. 5A shows the submount 10 viewed from below, and FIG. 5B shows a perspective view of the submount viewed from below.

[0152] [000177] The engaging mechanism 50B includes a rectangular outer wall 60 that is received within the opening of the pellicle frame (see FIG. 3). A pair of arms 62 extend in the y direction across 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 an example of an elastic member. Other elastic members can be used. The arms 62 and the connecting member 63 together generally form a U-shaped support. A locking member 70 is connected to the distal end of the generally U-shaped support. The locking member 70 engages a protrusion 51 (sometimes called a stud), thereby fixing the pellicle frame to the patterning device.

[0153] [000178] The locking member 70 includes a pair of engaging arms 80 provided with engaging tabs 81, and further includes a cap 66. As can be best seen in FIG. 5B, when the locking member 70 engages the protrusion 51, the engaging tabs 81 press against the lower surface of the distal head 53 of the protrusion, and the cap 66 presses against the outer surface of the distal head 53. By the engaging tabs 81 and the cap 66 pressing against the distal head 53 of the protrusion 51, the engaging mechanism 50B is fixed to the protrusion to provide a secure submount 10. Thereby, a secure connection is provided between the pellicle frame and the patterning device.

[0154] [000179] The cap 66 and the engaging arms 80 extend from intermediate arms 82a, b. The intermediate arms 82a, b extend from the connecting member 63 and generally extend in the opposite y direction across the space defined by the outer wall 60. A connecting member 83 extends between the intermediate arms 82a, b. The intermediate arms 82a, b and the connecting member 83 together generally form a U-shaped support.

[0155] [000180] Accordingly, the first generally U-shaped support formed by the arms 62 and the connecting member 63 extends in the y direction across the space generally defined by the outer wall 60, and the second generally U-shaped support formed by the support arms 82a, b and the connecting member 83 extends in the opposite direction across that space.

[0156] [000181] The arm 62 forming the first generally U-shaped support has a certain degree of flexibility in the x-direction, thereby allowing a certain degree of movement of the locking member 70 in the x-direction. Accordingly, the submount 10 allows a certain degree of movement of the pellicle frame relative to the patterning device at the location of the submount. Since the arms 62 are formed of an elastic material, they tend to return to their original orientation. The submount 10 can be regarded as a kinematic submount. The arms 62 are significantly thicker in the z-direction than in the x-direction (as can be best seen in FIG. 5B), and as a result, significantly less arm flexion is possible in the z-direction compared to flexion of the arms in the x-direction. Since the arms extend in the y-direction, they do not provide significant movement in the y-direction. Thus, the arms 62 can allow a certain degree of movement in the x-direction while preventing or substantially preventing local movement of the pellicle frame in the y- and z-directions.

[0157] [000182] The cap 66 extends from the first support arm 82a, and the engagement arm 80 extends from the second support arm 82b. Since the first support arm 82a is significantly thicker in the x-direction than the arm 62, it allows significant movement of the arm 62 in the x-direction. The second support arm 82b has the same thickness as the arm 62 in the x-direction, but the connecting member 83 extending between the intermediate arms 82a, b suppresses the movement of the second support arm 82b in the x-direction since such movement can only occur if the first support arm 82a also moves.

[0158] [000183] The engagement arm 80 extends in a general direction of the cap 66 from the second support arm 82b. The proximal end of the engagement arm 80 extends along a majority of the second support arm 82b (thus substantially preventing bending of the engagement arm 80 in a direction generally parallel to the patterning surface of the patterning device). The engagement arm 80 tapers as it extends 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 the lower surface of the distal head 53 of the projection 51. A block 54 is provided on the engagement tab 81 to provide an actuator receiving surface, as further described below. The engagement arm 80 is elastically deformable in the z direction. The engagement arm 80 may be thin enough to bend in the z direction. Additionally or alternatively, some bending of the engagement arm 80 in the z direction may be facilitated by a groove 59 extending in the y direction at the point where the engagement arm 80 connects to the support arm 82b.

[0159] [000184] The tab 56 extends outwardly from the outer wall 60. The tab can be used to secure the engagement mechanism 50B to the pellicle frame. This is shown in FIG. 3 with a different tab configuration.

[0160] [000185] FIG. 6 schematically shows a cross section of a pellicle attachment device 855 that can be used to attach a pellicle 19 to a pellicle frame 17. The pellicle attachment device 855 can correspond to the pellicle attachment device shown in FIG. 2. The pellicle frame 17 is supported by a support structure 101. The support structure 101 includes a raised portion 102 on which the pellicle frame 17 is placed. The pellicle 19 is held by a support arm 103 that protrudes downward from a frame (not shown). An imaging sensor 105 (e.g., a camera) is provided below the support structure 101 and looks through a window 107 provided on the upper surface of the support structure. An alignment mark 109 is provided on the window. The alignment mark 109 allows the imaging sensor 105 to determine the positions of both the frame 17 and the pellicle 19 (as will be discussed below with respect to FIG. 7). An actuator 111 is connected to the support structure 101 and is operable to move the support structure 101 relative to a base (not shown). The actuator 111 is configured to move the support structure 101 in the x, y, and z directions (in this document, x and y can indicate two orthogonal horizontal directions and z can indicate the vertical direction). The actuator is also configured to rotate the support structure 101 about the z axis. The actuator 111 can move the support structure 101 to position the frame 17 relative to the pellicle 19 before the pellicle is attached to the frame.

[0161] [000186] FIG. 7 schematically shows in more detail a part of the pellicle attachment device of FIG. 6, including the pellicle 19 and the pellicle frame 17. In FIG. 7, the relative positions of the imaging sensor 105, the window 107, the pellicle frame 17, and the pellicle 19 can be seen. The pellicle frame 17 partially protrudes above the window 107, and as a result, the imaging sensor 105 can see the edge of the frame 17. Thereby, the position of the frame 17 with respect to the alignment mark 109 provided on the window 107 can be accurately determined. The pellicle 19 has, near its outer periphery, a border 20 that is significantly thicker than the main part of the pellicle 19. This is the border 20 that is attached to the pellicle frame 17. In addition, this is the border 20 that is handled by the support arm 103 (shown in FIG. 6). As can be seen in FIG. 7, since the border 20 protrudes beyond the inner edge of the frame 17, the imaging sensor 105 can see the inner edge of the border. Thereby, the border 20 (and thus generally the pellicle 19) can be accurately positioned with respect to the alignment mark 109 within the window 107. Next, thereby, the border 20 (and the pellicle) can be accurately positioned with respect to the frame 17 (since the frame is accurately positioned with respect to the alignment mark 109 within the window 107).

[0162] [000187] The imaging sensor 105 and the window 107 can be arranged at the corner positions within the support structure 101, that is, the positions where the corners of the frame 17 are arranged during use. The imaging sensor 105 can be arranged at the opposite corner positions. By looking at the opposite corners of the frame 17, the imaging sensor 105 can accurately determine the position of the frame.

[0163] [000188] FIG. 8 is a perspective view of a handling system 113 that can be used to handle the pellicle 19. A handling system with the same configuration can also be used to handle the pellicle frame 17.

[0164] [000189] The support arm 103 of the handling system 113 holds the border 20 of the pellicle 19. The support arm is connected to the handling system frame 117 by a connector arm 115. The handling system frame 117 is fixed in the x and y directions but is movable in the z direction. A vacuum source (not shown) is connected to the conduit 119 of the handling system frame via a port 120. The conduit 119 is split into two and runs along each arm of the handling system frame 117. Each support arm 103 includes a conduit (not shown) that terminates at an opening provided in the leg 104 at the bottom of the support arm. Each conduit is connected to the conduit 119 within the handling system frame 117 via a bellows 121. Thus, the vacuum applied at the port 120 is connected to the opening within the leg 104 of the support arm 103 via the conduit 119 and the bellows 121. When the vacuum is applied, it sucks the border 20 of the pellicle 19 towards the leg 104 of each support arm 103, thereby fixing the border 20 to the support arm. Each leg 104 is dimensioned to receive the border 20 of the pellicle 19 (e.g., having a width corresponding to the width of the border). When the vacuum is removed, the border 20 is no longer sucked towards the leg 104 of the support arm 103 and is instead released from the support arm.

[0165] [000190] FIG. 9 is a perspective view showing a part of the handling system 113 in more detail and includes a connector arm 115 having a modified configuration compared to the configuration shown in FIG. 8. Each connector arm 115 includes a pair of leaf springs 123 that extend from the handling system frame 117 to the support arm 103. The leaf springs 123 provide flexibility in the z direction (i.e., vertically) but provide little or no flexibility in the x and y directions. This is achieved by leaf springs that are significantly thinner in the z direction than in the x and y directions. Since the bellows 121 used to send the vacuum to the support arm 103 are flexible, they permit relative movement of the support arm 103 with respect to the handling system frame 117.

[0166] [000191] The movement limiting arm 125 protrudes from the support arm 103 towards the handling system frame 117. An adjustable end stop 127 (for example, a bolt held in a threaded hole) is fixed to the handling system frame 117. The adjustable end stop 127 limits the downward movement of the movement limiting arm 125 (i.e., movement in the minus z direction). Thus, the adjustable end stop 127 prevents the downward movement of the pellicle 19 beyond a predetermined position.

[0167] [000192] When the pellicle is attached to the pellicle frame, in the first step, the handling system is used to pick up the frame. The handling system (not shown) can be generally the same as the handling system described above with respect to FIGS. 8 and 9. The legs at the bottom of each support arm can have a size and shape corresponding to the portion of the frame that will come into contact with the legs.

[0168] [000193] When the pellicle frame 17 is lifted by the handling system, the support structure 101 is positioned under the pellicle frame. The pellicle frame 17 is lowered up to a few millimeters above the support structure 101. Referring back to FIGS. 6 and 7, then the support structure 101 is moved using the actuator 111 until it is accurately positioned relative to the pellicle frame 17 (as determined using the imaging detector 105). Then, the pellicle frame 17 is lowered onto the support structure 101. Then, the vacuum holding the pellicle frame 17 against the handling system is released, and the handling system is separated from the pellicle frame 17. Then, glue is provided on the pellicle frame 17. The glue can be provided at spaced locations around the frame (rather than being provided to extend in a row around the frame).

[0169] [000194] The pellicle 19 is lifted by the handling system 113 as described above. Next, the support structure 101 is positioned under the pellicle 19 (along with the frame 17). The pellicle 19 is lowered using the handling system 113 above the support structure 101 by up to several millimeters. Next, the support structure 101 is moved using the actuator 111 until it is accurately positioned relative to the pellicle border 20. Next, the pellicle is lowered to the pellicle frame. When the pellicle 19 is placed on the frame 17, the vacuum is released from the support arm 103, and the support arm 103 is separated from the pellicle 19.

[0170] [000195] FIG. 10 schematically shows from above the pellicle 19 in a fixed position on the pellicle frame 17 held on the support structure 101. FIG. 10 schematically shows an arm 130 that holds the pellicle in a fixed position on the frame 17 while applying downward pressure to the pellicle border 20, thereby effecting curing of the glue that attaches the pellicle to the pellicle frame 17. The glue can be provided at spaced locations on the pellicle frame 17, and the arm 130 can be positioned to apply pressure at the locations where the glue is provided.

[0171] [000196] FIG. 11 shows a cross-section of one of the arms 130. The arm 130 includes a weighted portion 132 connected to a support portion 134 extending from a support frame 136. The weighted portion 132 includes a protrusion 138 in which a vertical bore 140 is provided. The protrusion 138 projects into an opening 142 of the support portion 134. A pin 144 extends from above the opening 142 downward and passes through the bore 140. Since both the pin 144 and the bore 140 are oriented in the vertical direction (z-direction), the arrangement of the pin and the bore allows for a certain degree of vertical movement of the weighted portion 132 relative to the support portion 134 of the arm 130. The range of vertical movement of the weighted portion 132 relative to the support portion 134 is limited by an end stop 146 provided at the mouth of the opening 142. The end stop is arranged to contact the protrusion 138, thereby preventing further vertical movement of the weighted portion 132.

[0172] [000197] The finger 148 extends downward from the weighting portion 132 of the arm 130. A cap 150 is provided at the lower end of the finger 148. The cap 150 can have a bottom surface that generally corresponds in size (or is larger than) the area of the glue provided on the pellicle frame 17. The finger 148 includes a vertical rod 152 that is fixed to the weighting portion 132 of the arm 130 at its uppermost end. The vertical rod 152 extends downward and passes through an opening 154 provided within the weighting portion 132. Since the opening 154 is substantially wider than the rod 152, it enables a certain degree of lateral movement of the lower end of the rod (and thus the lateral movement of the end of the finger). This is advantageous because the cap 150 can rest on the border 20 of the pellicle 19 without applying a large lateral force (which might occur if the rod 152 could not move freely laterally with respect to the weighting portion 132 of the arm 130).

[0173] [000198] During use, the support frame 136 holds the arm 130 away from the pellicle 19 until an arm is required. Thereafter, the support frame 136 moves the arm 130 downward until the finger 148 protruding below the arm contacts the border 20 of the pellicle 19. The downward movement of the support frame 136 stops before the convex portion 138 of the weighting portion 132 contacts the upper end stop 146 of the support portion 134. Thus, the weighting portion 132 rests on the border 20, presses against the border 20 via the finger 146, and is not supported by the support frame 136.

[0174] [000199] The downward pressure exerted on the border 20 by the weighting portion 132 is determined by the weight of the weighting portion. Thus, the weighting portion 132 can be configured to have a desired weight to apply a desired pressure to the border 20. The weighting portion 132 can include a weight receiving recess 149 within which a weight can be disposed. The weighting portion 132 can include any suitable weight receiving receptacle or protrusion.

[0175] [000200] Referring again to FIG. 10, the arm 130 is used to apply pressure at a desired location around the border 20 of the pellicle 19. The weighted portion 132 of the arm is left in place for a sufficient period of time to effect a certain degree of curing of the glue between the frame 17 and the border 20. Thereafter, the support frame 136 is moved upward to remove the weighted arm 132 from the border 20. The frame 17 and the pellicle 19 (collectively referred to as the pellicle assembly 16) can then be conveyed to an oven for further curing of the glue.

[0176] [000201] An embodiment of the pellicle frame attachment device 857 is shown in FIGS. 12-15. The pellicle frame attachment device 857 can correspond to the pellicle frame attachment device shown in FIG. 2. FIG. 12 schematically shows a cross-section of the pellicle frame attachment device 857. FIG. 13 shows the partition 862 of the pellicle frame attachment device 857 as viewed from above. FIG. 14 is a perspective view of the pins 1090, hook-shaped members 1091, and manipulator pins 1092 of the pellicle frame attachment device, which can be collectively referred to as a manipulator. The manipulator projects through holes 895 in the partition 862. FIG. 15 schematically shows a manner in which the pins 1090, hook-shaped members 1091, and manipulator pins 1092 can move relative to each other.

[0177] [000202] First, referring to FIG. 12, the pellicle assembly 16 includes a pellicle frame 17 and a patterning device MA provided with a pellicle (not shown). The frame 17 is provided with four engagement mechanisms 50 corresponding to the engagement mechanisms described above with respect to FIGS. 3 to 5. The pin 1090 of the pellicle frame attachment device 857 projects through the hole 895 in the partition 862. The partition 862 can correspond to the support structure 101 or be disposed on top of the support structure 101. The support structure 101 can be the same as the support structure 101 (see FIG. 6) that forms part of the pellicle attachment device. Alternatively, the support structure 101 can be different from the support structure 101 that forms part of the pellicle attachment device, but can optionally have common features. Windows 893, 894 are disposed within the support structure 101, and imaging sensors 105, 106 are disposed below the windows. Alignment marks 109 are provided on the windows 893, 894.

[0178] [000203] An additional support structure 97 is provided on the outer periphery of the pellicle frame attachment device 857. The additional support structure can have a fixed position (as shown in the figure) and is referred to herein as the 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 shown in the figure. The intermediate support structure 98 supports both the pellicle frame 17 and the patterning device MA prior to attachment of the pellicle frame to the patterning device. The contact 99 between the intermediate support structure 98 and other entities can be, for example, a kinematic connection. The contact 99 can be provided with a PEEK coating.

[0179] [000204] The pellicle frame attachment device 857 includes an actuator 111 that can be used to adjust the position of the pellicle assembly 16 in the x, y, and z directions and to rotate the pellicle assembly about the z direction. Two imaging sensors 105 (e.g., cameras) are positioned to view a portion of the pellicle (e.g., a corner of the pellicle border). Two other imaging sensors 106 (only one of which is shown in FIG. 12) are positioned to view alignment marks provided on the patterning device MA (which can be the patterning device MA). Since the alignment of the two entities using the alignment marks is well known in the art, it will not be described further herein. The actuator 111 and the imaging sensors 105, 106 can be collectively referred to as a control system 870.

[0180] [000205] A gas outlet (not shown) can be configured to supply gas on the pellicle frame 17 side of the partition 862. The gas can be delivered at a pressure higher than the gas pressure on the opposite side of the partition.

[0181] [000206] FIG. 13 shows the partition 862 in more detail. As can be seen from the figure, the partition 862 is provided with four windows. Two of the windows 893 are positioned so that the imaging sensor 106 can view the alignment marks provided on the patterning device MA. The other two windows 894 are positioned so that the imaging sensor 105 can view the pellicle frame 17 (e.g., view the corners of the pellicle frame). The windows 893, 894 can be formed, for example, from quartz.

[0182] [000207] The partition 862 is further provided with a hole 895, which is positioned to correspond to the position of the engagement mechanism 50 of the pellicle assembly 16. One of the holes 895 is shown in more detail in FIG. 14. The hole 895 is dimensioned such that the pin 1090 and the manipulator pin 1092 can project through the hole. The hook-shaped member 1091 projects from the side surface of the hole. In other words, the hook-shaped member 1091 is fixed to the partition 862 and projects from the partition. The pin 1090, the hook-shaped member 1091, and the manipulator pin 1092 are also shown in FIGS. 12, 13, and 15.

[0183] [000208] In use, the pellicle assembly 16 is loaded onto the pellicle frame mounting device 857. This can be transported to the pellicle frame mounting device 857 without being exposed to contaminants. For example, the pellicle assembly transfer device 881 can be received within a load lock (not shown) within the pellicle frame mounting device 857, and the pellicle assembly 16 can be removed from the transfer device within the load lock. The pellicle assembly 16 can then be transported to the controlled environment 857 above the partition 862.

[0184] [000209] In an embodiment, the pellicle assembly 16 can be manually positioned relative to the pellicle frame attachment device 857 using, for example, the handling system shown in FIG. 8. The pellicle assembly 16 is then placed on the intermediate support structure 98. The patterning device MA can be transported to the pellicle frame attachment device 857 (along with the stud 51) without being exposed to contaminants. For example, it is possible to receive the mask transfer device 881 within a load lock (not shown) within the pellicle frame attachment device 857 and remove the patterning device MA from the transfer device within the load lock. The patterning device MA can then be transported to the controlled environment 857 above the partition 862. In an embodiment, the patterning device MA can be manually positioned relative to the pellicle frame attachment device 857 using, for example, the handling system generally shown in FIG. 8. The patterning device is then placed on the intermediate support structure 98.

[0185] [000210] Further as described above, the controlled environment 859 above the partition 862 can be maintained at a pressure higher than the pressure below the partition (e.g., by delivering gas onto the partition). As can be understood from FIGS. 12 to 15, since the opening 895 within the partition 862 is relatively small, the possibility of contaminants passing through the opening and entering the controlled environment is limited. This possibility is further reduced by the higher pressure of the controlled environment 859 with respect to the environment within the feed partition 862. The higher pressure ensures that air flows downward through the hole 895, thereby carrying contaminants away from the pellicle 19.

[0186] [000211] When fixing the pellicle assembly 16 to the patterning device MA, imaging sensors 105 and 106 are used to monitor the position of the pellicle assembly relative to the patterning device MA. This occurs after the pellicle frame 17 is lifted from the intermediate support structure 98 by the pin 1090. The position of the pellicle frame 17 is adjusted using the actuator 111. This moves the support structure 101, and thus the pellicle frame 17 is moved relative to the patterning device MA. The operation of the actuator 111 can be manual or controlled by an automatic controller. The movement of the support structure 101 can continue until the pellicle frame 17 is aligned with the patterning device MA.

[0187] [000212] When the pellicle frame 17 is correctly positioned relative to the patterning device MA, the pin 1090, the hook-shaped member 1091, and the manipulator pin 1092 are used to engage the engagement mechanism 50 with the stud 51 protruding from the patterning device MA.

[0188] [000213] The manner in which pin 1090, hook-shaped member 1091, and manipulator pin 1092 can move relative to each other is schematically shown in FIG. 15. As described above, since the hook-shaped member extends from the support structure 101, it cannot move relative to the support structure. The support structure 101 itself is movable as described above, generally including movement in the vertical direction (z-direction). The manipulator pins 1092 are generally movable in the vertical direction (z-direction) by the actuator 320. Since both manipulator pins 1092 are fixed to the actuator 320, they both move together. The pin 1090 that supports the pellicle frame 17 cannot move actively relative to the manipulator pins 1092. The pin 1090 is connected to the actuator 320 via a spring 322. As a result, unless the pin is in contact with the pellicle frame 17, upward and downward movement of the actuator 320 will cause corresponding movement of the pin 1090. When the pin 1090 is in contact with the pellicle frame 17, further movement of the actuator 320 will not cause further upward movement of the pin, but instead will cause compression of the spring 322. When the spring 322 is compressed, downward movement of the actuator 320 will not cause downward movement of the pin 1090 until the spring 322 expands to a relaxed configuration.

[0189] [000214] FIGS. 16 and 17 schematically show the manner in which the engagement mechanism 50 engages with a protrusion 51 (sometimes referred to as a stud). Both figures show a cross-section of the engagement mechanism and the protrusion as viewed from one side and from below. First, referring to FIG. 16, using a manipulator pin (not shown) that pushes the distal end of the engagement arm, the engagement arm 80 is pushed out of the cap 66. As can be seen from FIG. 16, at this point, the engagement mechanism 50 and the protrusion 51 are not in contact.

[0190] [000215] The engagement mechanism is moved in the x direction until the distal head 53 of the protrusion 51 is placed on the engagement tab 81 protruding from the engagement arm 80. This movement is achieved by moving the pellicle frame, with the engagement mechanism 50 fixed, and thus moving all the engagement mechanisms integrally.

[0191] [000216] When the engagement mechanism 50 reaches its fixed position, the manipulator pin that has been pushing the engagement arm 80 away from the distal head 53 of the protrusion 51 is removed. Since the engagement arm 80 is elastic, it moves downward and presses against the inner surface of the distal head 53. Thus, the engagement tab 81 presses the distal head 53 against the cap 66, thereby fixing the engagement mechanism 50 to the protrusion 51. This is shown in FIG. 17.

[0192] [000217] There may be cases where it is desirable to remove the pellicle assembly 16 from the patterning device MA (for example, when contaminants are detected on the pellicle). This removal can be performed by the pellicle frame attachment device 857. To cut the engagement mechanism 50 from the protrusion 51, the above is done in reverse order.

[0193] [000218] The operations of the pin 1090, the hook-shaped member 1091, and the manipulator pin 1092 can be manual, automatic, or semi-automatic.

[0194] [000219] The pin 1090, the hook-shaped member 1091, and the manipulator pin 1092 can be formed of, for example, steel. A coating of a material such as polyetheretherketone (PEEK) or some other robust material can be provided on the surfaces of the pin 1090, the hook-shaped member 1091, and the manipulator pin 1092 that contact the engagement mechanism 50. Alternatively, the contact surfaces can simply be the polished surfaces of the pin 1090, the hook-shaped member 1091, and the manipulator pin 1092.

[0195] [000220] When the pellicle assembly 16 and the patterning device MA are both connected to form the mask assembly 15, the mask assembly can be placed within the mask assembly transfer device 853 for transfer to the lithographic apparatus LA (see Figure 2).

[0196] [000221] Figures 18A - 18H show in more detail one mode in which the engagement mechanism 50 can engage with the projection 51. Referring to Figure 18A, the pin 1090 is moved in the z - direction until it touches the cap 66 of the engagement mechanism 50. The pin 1090 is further moved in the z - direction so as to lift the engagement mechanism 50. Since the engagement mechanism is fixed to the frame 17 (see Figure 3), this lifts the entire pellicle assembly 16. The pin 1090 is one of four pins (see Figures 12 and 13) and the pins are moved integrally. Thus the pellicle assembly 16 is lifted and supported by the four pins 1090. Then the position of the pellicle assembly 16 is adjusted using the actuator 111 (see Figure 12) until the pellicle assembly is aligned with the patterning device MA.

[0197] [000222] Referring to Figure 18B, thereafter, the two hook - shaped members are moved in the z - direction until their distal ends extend beyond the top surface of the first support arm 82a. Then the hook - shaped member 1091 is moved in the x - direction until the distal end of the hook - shaped member is above the corner plate 1089 of the support arm 82a.

[0198] [000223] As shown in Figure 18C, thereafter, the hook - shaped member 1091 is moved downward until it contacts the corner plate 1089 of the support arm 82a. Both the pin 1090 and the hook - shaped member 1091 grip the engagement mechanism 50 to enable subsequent operation of the engagement mechanism.

[0199] [000224] Referring to FIG. 18D, the manipulator pin 1092 is generally moved in the vertical direction, pressing against the block 54 provided at the distal end of the engagement arm 80. Since the manipulator pin 1092 pushes the engagement arm 80 upward, the space between the engagement tab 81 and the cap 66 is enlarged thereby. In FIG. 18D, due to the limitations of the software used to generate the figure, the engagement arm 80 is not bent upward.

[0200] [000225] Referring to FIGS. 18E and 18F, the engagement mechanism 50 is then moved in the x direction until the distal end 53 of the protrusion 51 is positioned over the cap 66 and under the engagement tab 81.

[0201] [000226] As further described above, all the engagement mechanisms 50A - D are moved integrally via the movement of the pin 1090 (see FIG. 3). In an alternative arrangement, instead of moving the pellicle frame, the patterning device and all the protrusions 51 can be moved. Generally, only the relative lateral movement between the protrusion and the engagement mechanism is required. The direction of the lateral movement depends on the orientation of the engagement arm 80 (and can be, for example, the y direction instead of the x direction).

[0202] [000227] Referring to FIG. 18F, when the cap 66 is positioned under the distal head 53 and the engagement tab 81 is over the distal head 53, the manipulator pin 1092 is retracted. Due to elasticity, the engagement arm 80 returns to its original position, pressing the engagement tab 81 against the distal head 53. The engagement tab 81 presses the distal head 53 against the cap 66. Thereby, the engagement mechanism 50 is fixed to the protrusion 51.

[0203] [000228] Referring to FIG. 18G, the hook - shaped member 1091 is moved in the x direction after being moved upward until it is positioned away from the corner plate 1089 of the support arm 82a. Thereafter, the hook - shaped member 1091 is retracted.

[0204] [000229] Referring to FIG. 18H, in the final step, pin 1090 is stored. Referring to FIG. 12, when pin 1090 is retracted, the pellicle frame 17 is no longer supported by the pin, but instead is supported by its connection to protrusion 51 protruding from the patterning device MA. In other words, the pellicle frame 17 is attached to and supported by the patterning device MA.

[0205] [000230] Since the engagement mechanism 50 is fixed to the protrusion 51, a secure submount 10 is provided for the pellicle frame (see FIG. 3). Thus, the pellicle frame is securely attached to the patterning device. The pellicle, the pellicle frame, and the patterning device (which can be collectively referred to as a mask assembly) can then be placed in the transfer device 853 for transfer to the lithographic apparatus LA (see FIG. 2).

[0206] [000231] The steps shown in FIGS. 18A - 18H are performed in reverse to remove the engagement mechanism 50 from the protrusion 51, thereby removing the pellicle frame from the patterning device.

[0207] [000232] None of the steps used when the engagement mechanism 50 is fixed to the protrusion 51 require any sliding movement between components. In other words, there is no need for the surfaces to rub against each other in a sliding movement. This is advantageous as such rubbing can generate undesirable particulate contaminants.

[0208] [000233] An alternative sequence of steps (not shown) can be used to attach the engagement mechanism 50 to the protrusion 51. In this alternative sequence, the hook-shaped member 1091 is moved to a position above the engagement tab 1089 before using a pin to raise the pellicle frame. After the hook-shaped member 1091 is placed in a fixed position, the pin 1090 is moved upward to press against the engagement mechanism. Thus, the engagement mechanism is gripped by the hook-shaped member 1091 and the pin 1090. Thereafter, the engagement mechanism 50 is lifted by moving the hook-shaped member 1091 and the pin 1090 upward. Since the same operation is performed for other engagement mechanisms, the pellicle assembly is lifted. Thereafter, the pellicle assembly is aligned with the patterning device using the actuator 101 and the imaging sensors 105, 106 (see FIG. 12). The remaining steps can be as described above with reference to FIGS. 18A-18H.

[0209] [000234] Next, with reference to FIGS. 19-27, embodiments of a stud attachment and stud removal device will be described.

[0210] [000235] FIG. 19 schematically shows a cross-section of a stud attachment device 840 according to an embodiment of the present invention. The stud attachment device 840 has similarities to the pellicle attachment device 855 shown in FIG. 6 and the pellicle frame attachment device 857 shown in FIG. 12. Each part of the stud attachment device 840 can correspond to those parts of other devices.

[0211] [000236] The stud mounting device 840 includes a support structure 101 and a stud manipulator 1100 configured to vertically move a protrusion 51 (sometimes called a stud) so as to contact the patterning device. Windows 107, 108 are provided within the support structure 101, and imaging sensors 105, 106 (e.g., cameras) are positioned to look through the windows towards the patterning device MA. Alignment marks 109 are provided on the windows and can be used to align the support structure 101 with respect to the patterning device MA. An actuator 111 is provided to move the support structure 101, and thus move the stud 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 about the z axis. The actuator 111 can be automatic, manual, or semi-automatic (i.e., partially automatic and partially manual). The stud mounting device 840 further includes an additional support structure 97 configured to support the patterning device MA. This additional support structure is fixable and is referred to herein as the fixed support structure 97.

[0212] [000237] During use, while the stud is held by the support structure, glue is provided at the base of each stud 51. Then, the patterning device MA is placed on the fixed support structure 97 such that the patterning device MA is positioned several millimeters above the support structure 101. The actuator 111 is used to move the support structure 101 until the alignment marks 109 provided within the windows 107, 108 are aligned with the alignment marks provided on the patterning device MA. The stud 51 is held by the stud manipulator 1100 and has a fixed position in the x and y directions relative to the support structure 101. The separation between the studs 51 (which may actually be four) is a fixed predetermined separation. The separation between the studs 51 corresponds to the separation between the engagement members 50A - D provided on the pellicle frame 17 (see FIG. 3) that is to be attached to the patterning device MA.

[0213] [000238] When the support structure 101 is correctly positioned relative to the patterning device MA, the support structure is moved upward and closer to the patterning device. Then, using the stud manipulator 1100, the stud 51 is moved upward from a position where the base of the stud is not in contact with the patterning device MA to a position where the base of the stud presses against the patterning device. Then, a heater is 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.

[0214] [000239] Figure 20 shows the stud attachment device 840 in a partially transparent perspective view. A partition 842 is shown that separates an actuator (not visible) from a controlled environment in which a patterning device is provided. The actuator is provided within a box 843 disposed beneath the partition 842. Imaging sensors 105, 106, which form part of an alignment measurement system 844 for aligning the studs and the patterning device, are also provided beneath the partition 842 (similar to other parts of the alignment system).

[0215] [000240] Figure 20 also shows a lift unit 845 that can be used to raise and lower a mask support for placing a patterning device on a fixed support 97 (see Figure 19). The mask support can comprise a housing 879 that will form part of a mask transfer device 880 (further described above with respect to Figure 2). The patterning device (not visible) and the housing 879 can be provided within the controlled environment (whose walls are not shown) together with the lift unit 845. The controlled environment can be maintained at a pressure higher than the pressure on the opposite side of the partition 842 such that contaminants are suppressed from flowing into the controlled environment through an opening within the partition. It is possible to provide a flow of gas from an inlet to the controlled environment and include an outlet through which gas can flow (the flow being sufficiently restricted such that the pressure within the controlled environment can be maintained at a level higher than the pressure beneath the partition 842). This flow of gas can help remove contaminants from the controlled environment. A filter for collecting contaminants can be provided at the gas inlet to prevent or suppress contaminants from entering the controlled environment.

[0216] [000241] At the points where the mask contacts the stud attachment device 840, a coating of PEEK or some other robust material can be provided. Similarly, at the points where the mask contacts the housing 879, a coating of PEEK or some other robust material can also be provided.

[0217] [000242] A part of the stud attachment device 840 is shown in more detail in FIG. 21. The stud manipulator 1100 is shown together with the stud 51 and the patterning device MA (for example, a mask). A partition 842 is also shown that separates the environment in which the patterning device is provided from the environment in which the stud manipulator 1100 is provided. The stud manipulator 1100 includes a cup 1102 sized to receive the stud 51 (sometimes called a projection) such that the bottom surface of the stud 51 faces outward from the cup. The cup 1102 can be formed from, for example, PEEK or some other robust material. The cup 1102 is held within the manipulator head 1104, and the manipulator head is supported on the manipulator body 1106. A spring 1108 is received against a flange 1109 provided on the manipulator body, applying an upward bias to the manipulator head 1104 and the stud 51. Alignment of the stud 51 with respect to the mask is achieved using the imaging sensors 105, 106 and the actuator 111 shown in FIG. 19. When the actuator aligns the stud 51 with respect to the patterning device MA, the stud manipulator 1100 is moved upward to press the stud against the patterning device. The stud manipulator 1100 is moved upward by an actuator (not shown) that moves all four stud manipulators upward simultaneously. When the stud manipulator 1100 presses 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. The weaker the spring, the less the force with which the stud is pressed against the patterning device, and the stronger the spring, the greater the force with which the stud is pressed against the patterning device. Thus, the force with which the stud 51 is pressed against the patterning device MA can be (at least partially) selected by choosing a spring 1108 with the desired force. The spring 1108 can be pre-loaded, for example, with a force that pushes the stud manipulator 1100 and the stud 51 upward. The pre-load force can be, for example, less than 5 N.

[0218] [000243] The stud manipulator 1100 can press the stud 51 against the patterning device MA, thereby fixing the stud to the mask. As described above, it is possible to provide glue or an adhesive on the base of the stud, and the stud manipulator 1100 can press the stud 51 against the patterning device MA until the glue or adhesive hardens. When this is done, the stud manipulator 1100 can be separated from the patterning device MA (and / or the patterning device can be separated from the stud manipulator 1100).

[0219] [000244] In an embodiment, the stud manipulator 1100 can include a heater 1111 configured to heat the stud 51. The heater 1111 can be in the form of an electric heater (e.g., a resistive electric heater). When the stud 51 is held against the patterning device MA, the heater 1111 is used to heat the stud. The local heating of the stud 51 provided by the heater 1111 is advantageous for accelerating the curing of the glue or adhesive. This improves the throughput of the stud attachment device 840. The curing provided by heating the stud 51 can be a pre-cure or a full cure. If a pre-cure is used, the patterning device MA and the stud 51 can be transported to an oven for curing. If the heating of the stud 51 provides a full cure, there is no need to transport the mask and the stud to an oven. This is advantageous because the oven can be a source of contaminating particles.

[0220] [000245] In an embodiment, the stud manipulator 1100 can include (in addition to, or instead of, the spring 1108) an actuator (not shown) operable to press the stud 51 against the patterning device MA. The actuator can also, when the stud is fixed to the patterning device MA, separate the cup 1102 from the stud 51.

[0221] [000246] The seal 1112 extends around the outer periphery of the manipulator head 1104. The seal 1112 is most clearly seen in FIG. 22, which shows a portion of the stud manipulator 1100 viewed from above (with the overall transparent patterning device MA removed for ease of illustration). As can be seen in FIG. 22, in the illustrated embodiment, the seal 1112 is annular. However, the seal may be of any suitable shape.

[0222] [000247] Referring again to FIG. 21, the seal 1112 is formed from an elastic material (e.g., PEEK) and projects over the partition 842 and over the stud 51. Thus, when the stud is pressed against the patterning device MA, the seal 1112 is pushed downward. The elasticity of the seal 1112 means that the seal is formed against the patterning device by the seal being pressed against the patterning device MA. This seals the portion of the patterning device MA that is within the outer periphery of the seal 1112 and isolates it from the portion of the patterning device MA that is outside the outer periphery of the seal.

[0223] [000248] A gas extraction channel 1114 is provided within the manipulator head 1104, and the gas extraction channel extends outwards from the outer surface of the manipulator head. An additional gas extraction route is provided by an annular space 1115 around the manipulator head 1104. A gas delivery channel 1118 is provided on one side of the seal 1112 and can deliver gas to the area of the patterning device MA disposed inside the seal. This is schematically shown by the arrow in FIG. 21. The gas is extracted via the gas extraction channel 1114 within the manipulator head and the annular space 1115 around the manipulator head. The gas extraction channels 1114 are distributed around the manipulator head 1104 as best seen in FIG. 22. A gas flow is provided that will transfer contaminants outside the gas extraction channels 1114 and the annular space 1115, thereby preventing those contaminants from adhering to the surface of the patterning device MA. The contaminants can be, for example, particles derived from the glue provided on the stud 51, or chemical vapors from the glue. Chemical vapors can be generated especially when the glue is heated for curing. Removing contaminants using a gas flow is advantageous because, as explained elsewhere, particles or other contaminants on the surface of the patterning device MA can cause errors in the pattern projected onto the substrate by the lithographic apparatus. The gas can be, for example, air.

[0224] [000249] In an embodiment, the seal 1112 can be a complete seal, i.e., no gas can flow past the seal. In an alternative embodiment, the seal 1112 may form an incomplete seal with respect to the patterning device MA such that some gas can flow between the seal and the mask. This can be referred to as a leaky seal (i.e., the seal 1112 is a leaky seal). The seal 1112 may, for example, not be able to contact the patterning device such that there is a gap between the seal and the patterning device. The gas pressure inside the seal may be lower than the gas pressure outside the seal, and as a result, gas will flow from outside the seal into the seal and then out through the gas extraction channel 1114 and the annular space 1115. This is advantageous because contaminant particles will be transported by the gas that passes through the seal and out of the extraction channel 1114 from the area of the patterning device MA outside the seal 1112. A further advantage of the leaky seal configuration is that it prevents contaminants from being transported from the seal to the patterning device by avoiding contact between the seal 1112 and the patterning device MA.

[0225] [000250] FIG. 23 is a perspective view of four studs 51 provided on the support structure 101, each stud being surrounded by a seal 1112. Each seal 1112 is held on a seal support plate 1113 fixed to the support structure 101. FIG. 23 also shows two windows 108 through which the imaging sensor 106 (see FIG. 19) can view the patterning device MA (not shown).

[0226] [000251] Each seal support plate 1113 can be removed from the support structure 101 together with the associated seal 1112 (e.g., so that a worn seal can be replaced). FIG. 24 shows one seal support plate 1113 and seal 1112 removed from the support structure 101. As can be seen in the figure, positioning pins 1120 extend upward from the support structure 101. These positioning pins 1120 are received within holes (one of which is visible in FIG. 21) within the seal support plate 1113, thereby ensuring that the seal support plate is correctly positioned on the support structure 101.

[0227] [000252] A retaining arm 1122 extends from a block 1124. The retaining arm 1122 is disposed over the seal support plate 1113 and presses against a pin 1126 that extends upward from the support structure 101. The retaining arm 1122 is elastically biased against the pin 1126 to press against it, thereby securely holding the seal support plate 1113 in a fixed position on the support structure. The resilient retaining arm 1122 can be manually released from the pin 1126 by moving the opposing arms toward each other, thereby allowing the seal support plate 1113 (and seal 1112) to be removed.

[0228] [000253] Only the stud 51 (and the seal 1112 if no leak seal is used) is in contact with the patterning device. When the stud 51 is pressed against the patterning device MA, the stud manipulator 1100 is flexibly connected to the support structure 101 to allow the stud manipulator to move relative to the support structure. This flexible connection is provided via a spring 1108. As a result, when the stud 51 is pressed against the patterning device MA, the stud manipulator 1100 is movable relative to the support structure 101. This is advantageous in order to avoid applying a large lateral force to the interface between the stud 51 and the patterning device MA, thereby avoiding, for example, a sliding movement of the stud across the surface of the patterning device (such movements can generate contamination and are undesirable).

[0229] [000254] A kinematic connection is provided between the stud manipulator 1100 and the support structure 101. The kinematic connection allows the stud manipulator 1100 to press against the support structure when the stud 51 is not in contact with the patterning device, but allows the stud manipulator to be easily disengaged from the support structure 101 when the stud 51 is in contact with the patterning device. Referring again to FIG. 24, three protrusions 1130 with rounded heads project from the stud manipulator 1100 and are distributed around the stud manipulator. In FIG. 21, one of the three protrusions 1130 is visible. The protrusions 1130 engage with the inclined inner surface 1132 of the seal support plate 1113. The inclined inner surface 1132 is generally flat, but as described above, the protrusions 1130 have rounded upper surfaces. This combination of surfaces is advantageous because it provides a very small contact area between the protrusions 1130 and the inclined inner surface 1132. The other two protrusions similarly contact the inclined inner surface of the seal support plate.

[0230] [000255] When the stud 51 is not in contact with the patterning device MA during use, the spring 1108 presses the protrusion 1130 against the inclined inner surface 1132 of the seal support plate 1113. This provides a connection between the stud manipulator 1100 and the support structure 101. The connection can be a kinematic connection. When the stud 51 is pressed against the patterning device MA, the spring 1108 is compressed, thereby separating the protrusion 1130 from the inclined inner surface 1132 of the seal support structure 101. The three protrusions 1130 do not all separate from the inclined inner surface 1132 simultaneously, for example, if there is a relative inclination between the patterning device MA and the support structure 101. Instead, after one separates, the second follows, and then the third separates. The kinematic connection enables this sequential separation and allows the stud 51 to maintain a substantially perpendicular orientation with respect to the patterning device MA. In other words, the kinematic connection prevents the stud 51 from having the orientation determined by the support structure 101 and instead allows the stud to have the orientation determined by the patterning device MA.

[0231] [000256] There may be cases where it is desirable to remove the stud 51 from the patterning device MA. This removal can be performed by a stud removal device. The stud removal device can generally have a form corresponding to the stud attachment device 840 (for example, as schematically shown in FIG. 19). For example, the stud removal device can include a partition that separates the controlled environment in which the patterning device MA is held during stud removal from the stud remover and other components. The stud removal tool can include, for example, a stud remover having a configuration corresponding to the configuration shown in FIG. 19. To achieve the removal, in embodiments, the imaging sensors 105, 106 and windows 107, 108 may not be required in the stud removal device since a relatively coarse alignment of the stud remover with respect to the stud 51 is sufficient. The alignment of the heater and actuator with respect to the stud can be performed using a manual, semi-automatic, or automatic system.

[0232] [000257] Figure 25 is a perspective view of a stud remover 1149 that forms part of a stud removal device according to an embodiment of the present invention. The stud remover 1149 includes a stud gripper 1154 connected to a support plate 1155. A weight 1157 extends downward from the stud gripper 1154. A pair of leaf springs 1159 extends downward from the support plate 1155 and is configured to allow movement of the stud gripper 1154 in the x direction (leaf springs are generally movable in the vertical direction).

[0233] [000258] An actuator 1161 is connected to a flange 1163 that protrudes downward from the support plate 1155. The actuator includes an arm 1164 that passes through an opening in one of the leaf springs 1159 and connects to a hook-shaped member 1165 that is in contact with the weight 1157. A raised and grooved connection 1175 is provided between the hook-shaped member 1165 and the weight 1157 to allow the weight to move vertically relative to the hook-shaped member while preventing relative movement of the hook-shaped member and the weight in the x and y directions. Thus, by using the actuator 1161 to move the arm 1163 in the x direction, the hook-shaped member 1165 and the weight 1157 will move in the x direction.

[0234] [000259] A second pair of leaf springs 1167 (only one of which is visible in Figure 25) allows movement of the stud gripper 1154 in the y direction. No y-direction actuator is provided. Instead, some passive movement in the y direction can occur when the stud moves into the stud gripper 1154 (as described below).

[0235] [000260] An actuator 1169 is disposed under the hook-shaped member 1165 that is connected to the weight 1157 via the raised and grooved connection 1175 (the weight is connected to the stud gripper 1154). The actuator 1169 is operable to move the stud gripper 1154 in the vertical direction (shown as the z direction in this case).

[0236] [000261] Thus, the movement of the stud gripper 1154 in the x, y, and z directions is provided by the stud remover 1149.

[0237] [000262] The weight 1157 can be, for example, at least 1 kg. The weight can be, for example, about 3 kg.

[0238] [000263] The receptacle 1173 is provided adjacent to the z-direction actuator 1169 and is configured to receive the studs removed from the patterning device.

[0239] [000264] FIGS. 26 and 27 are a perspective view and a cross-sectional view showing a part of the stud remover 1149 in more detail. FIG. 27 also includes the stud 51 and the patterning device MA (e.g., a mask). The stud gripper 1154 includes a pair of opposing flanges 1156 that extend towards each other to establish a gap that is wider than the neck of the stud 51 but narrower than the distal head 853 of the stud. Below the opposing flanges 1156, a recess 1158 is provided that is wider than the distal head of the stud 51 and is thus capable of receiving the distal head of the stud. The distal head of the stud 51 cannot be clearly seen in FIGS. 26 and 27 because the head extends inside and outside the plane of the figure. The recess 1158 and the opposing flanges 1156 flare outwards at one end of the stud gripper 1154.

[0240] [000265] The stud remover 1149 includes a heater 1188 disposed below the stud gripper 1154. The heater is an electric heater, for example a resistance heater, and is configured to locally apply heat to the stud gripper 1154. The stud remover further comprises a pusher arm 1200 connected to an actuator 1202. The pusher arm 1200 is configured to push the stud 51 and to enter the chute 1204 when removed from the patterning device MA. The chute 1204 leads to a receptacle 1173 (see FIG. 25).

[0241] [000266] A wire 1206 extends downwardly from the heater 1188 and is connected to a weight 1157 (see FIG. 25).

[0242] [000267] In use, the actuator stud gripper 1154 is initially located to the left of the stud and does not project above the partition 1142 of the device. Thereafter, the stud gripper 1154 is moved upwardly using the vertical actuator 1169 (see FIG. 25) to the position shown in FIG. 27. Thus the stud gripper is adjacent to but not in contact with the patterning device MA. Next, the x-direction actuator 1161 (see FIG. 25) moves the stud gripper 1154 in the x-direction such that the distal head 853 of the stud 51 enters the stud gripper via its flare end and is then disposed within the non-flared portion (as shown in FIG. 28). This may include some passive movement of the stud gripper 1154 in the y-direction. Thereafter, the support plate 1155 no longer supports the stud gripper 1154 and instead the vertical actuator 1169 is moved downwardly such that the stud gripper is pulled downwardly by the weight 1157. Heat is sent from the heater 1188 to the stud 51 via the stud gripper 1154 to melt the glue or adhesive fixing the stud to the patterning device MA. When the glue or adhesive melts, the stud 51 is detached from the patterning device MA. The stud 51 moves downwardly due to the weight pulling it downwardly.

[0243] [000268] Thereafter, the pusher arm 1200 is moved in the x direction as shown in FIG. 29. This pushes the stud 51 from the stud gripper 1154 into the chute 1204. Thereafter, the stud falls into the receptacle 1173. In FIG. 29, the stud 51 is shown in three places to indicate the movement of the stud.

[0244] [000269] The above process is executed for each stud 51 on the patterning device MA. The studs can be removed consecutively, i.e., one after another. Alternatively, all the studs can be removed together. The advantage of removing the studs consecutively is that the force applied to the patterning device is limited to the force required to remove one stud. This in turn limits the force applied to the supports that support the patterning device, thereby minimizing the risk of damaging those supports (and also minimizing the risk of damaging the patterning device).

[0245] [000270] As described above, the partition 1142 separates most of the stud removal device from the controlled environment in which the patterning device MA is provided. However, no seal extends around the area of the patterning device MA where the studs 51 are provided. After the studs 51 are removed, the patterning device MA is cleaned, and since the addition of contaminants to the patterning device during stud removal does not cause significant problems, the seal provides little benefit. A seal can be provided if desired (e.g., a leak seal).

[0246] [000271] The stud removal device can further include additional stud grippers 1154 and associated elements. For example, one, four stud grippers and other elements can be provided for each stud on the patterning device MA. The stud removal device can generally be in a form corresponding to the stud attachment device 840 shown in FIG. 21. For example, an actuator can be used to adjust the position of the stud gripper in the x, y, Z, and Rz directions. The actuator can be automatic, manual, or semi-automatic (i.e., partially automatic and partially manual). The partition 1142 can separate the actuator from the controlled environment where the mask is provided. The actuator can be provided in a box disposed under the partition 1142. An alignment measurement system can also be provided under the partition 842. The alignment measurement system can include, for example, an imaging system used to ensure that the stud gripper 1154 is positioned in the correct place before engaging the stud 51.

[0247] [000272] At the point where the mask contacts the stud attachment device 1150, a coating of PEEK or some other robust material can be provided. Similarly, at the point where the mask contacts the housing, a coating of PEEK or some other robust material can be provided.

[0248] [000273] The stud attachment device 840 and the stud removal device 1150 can be provided as a single device or as separate devices.

[0249] [000274] The lift unit 845 and the housing are shown only in FIG. 20 and are shown as part of the stud attachment device 840. However, the lift unit can similarly be provided as part of a pellicle frame attachment and / or removal device and / or can similarly be provided as part of a stud removal device. The lift unit can be configured to raise and lower a housing that can form part of a mask transfer device. A patterning device (e.g., a mask) can be held by the housing. The mask, the housing, and the lift unit can be provided within a controlled environment.

[0250] [000275] In an embodiment, instead of using a weight to remove the stud 51 from the patterning device MA, an actuator can be used to apply a downward force to the stud. The actuator can be, for example, a Lorentz actuator. The Lorentz actuator can be configured to pull the stud only in the z-direction.

[0251] [000276] In an embodiment, instead of heating the stud 51, the patterning device MA can be heated (e.g., using a heater disposed on the patterning device). The advantage of this approach is that the glue tends to crack at the interface with the patterning device, such that little glue remains on the patterning device when the stud is removed.

[0252] [000277] In an embodiment, instead of heating to melt the glue, a suitable solution can be applied to dissolve the glue.

[0253] [000278] The glue can be cleaned from the patterning device MA using a cleaning device. The cleaning device can form part of the stud removal device or be provided as a separate device. The patterning device MA can be placed in a sealed box for transfer to the cleaning device. The cleaning device can be configured to remove contaminants from the mask (which can include the removal of glue from the mask).

[0254] [000279] Although some embodiments of the present invention have been described in relation to studs, if the circumstances permit, embodiments of the present invention can use any form of protrusion.

[0255] [000280] In the described embodiments, the frame 17 and the mounting 50 are attached to each other before the pellicle 19 is attached to the frame, and the attachment of these elements can be performed in any suitable order. For example, the frame 17 and the pellicle 19 can be fixed together, and then the mounting 50 can be attached to the frame. The mounting 50 can generally be attached to the frame 17 using an attachment device corresponding to the pellicle attachment device 855.

[0256] [000281] References to masks in this document can be interpreted as references to patterning devices (a mask is an example of a patterning device).

[0257] [000282] References to glue in this document can be interpreted as references to common adhesives.

[0258] [000283] Although this text particularly refers to embodiments of the invention in the context of a lithographic apparatus, embodiments of the invention can be used in other apparatuses. Embodiments of the invention can form part of a mask inspection apparatus, a metrology apparatus, or any apparatus for measuring or processing an object such as a wafer (or other substrate) or a mask (or other patterning device). These apparatuses can generally be referred to as lithographic tools. Such lithographic tools can use a vacuum situation or an atmosphere (non-vacuum) situation.

[0259] [000284] The term "EUV radiation" can be considered to encompass electromagnetic radiation having a wavelength in the range of 4 - 20 nm, for example in the range of 13 - 14 nm. EUV radiation can have a wavelength in the range of 4 - 10 nm, less than 10 nm, for example 6.7 nm or 6.8 nm.

[0260] [000285] Although this text particularly refers to the use of a 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.

[0261] [000286] Although specific embodiments of the invention have been described above, it will be understood that the invention can be practiced otherwise than as described. The above description is intended to be illustrative and not restrictive. Thus, those skilled in the art will understand that modifications can be made to the invention described without departing from the scope of the claims set forth below.

Claims

1. 1. 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, the stud manipulator is separated by a partition from a patterning device receiving a controlled environment; A stud mounting arrangement, wherein the partition includes holes through which the studs protrude to contact the patterning device.

2. the stud manipulator is one of a plurality of stud manipulators; The stud attachment device of claim 1 , wherein the hole in the partition is one of a plurality of holes.

3. the stud attachment apparatus includes a gas exhaust within the controlled environment; The stud installation device of claim 1 , wherein the gas outlet is configured to supply gas at a pressure greater than the gas pressure on an opposite side of the partition.

4. The stud attachment apparatus of claim 1 , wherein a seal is provided around the periphery of the stud manipulator that, in use, provides a seal against the patterning device to isolate a stud receiving portion of the patterning device from other portions of the patterning device.

5. The stud attachment apparatus of claim 4 , wherein at least one gas delivery channel and at least one gas extraction channel are provided through which gas flow is provided to and from the stud receiving portion of the patterning device.

6. The stud mounting apparatus of claim 4 , wherein the seal is a leak seal.

7. The stud installation apparatus of claim 1 , wherein the stud manipulator includes a heater.

8. The stud attachment apparatus of claim 1 , wherein the partition includes a window positioned such that alignment marks on the patterning device are visible from the opposite side of the partition.

9. The stud attachment apparatus of claim 8 , wherein an imaging sensor is provided on one side of the window and configured to look through the window to view the alignment marks on the patterning device.

10. The stud installation device of claim 1 , wherein a kinematic connection is provided between the stud manipulator and the support structure.

11. 1. A method of attaching studs to a patterning device, comprising the steps of: Placing the stud in a stud manipulator provided on a support structure; applying glue to the studs; placing the patterning device over the studs with a patterned surface facing downwards; moving the stud manipulator upwards to move the stud into contact with the patterning device; providing a seal around the stud manipulator that, in use, provides a seal against the patterning device to isolate a stud receiving portion of the patterning device from other portions of the patterning device; A method comprising:

12. A method of attaching a stud to a patterning device, comprising the steps of: Placing the stud in a stud manipulator provided on a support structure; applying glue to the studs; placing the patterning device over the studs with a patterned surface facing downwards; moving the stud manipulator upwards to move the stud into contact with the patterning device; aligning the studs with respect to alignment markers present on the patterning device to accurately position the studs; A method comprising:

13. The method of claim 11, wherein after gas is delivered to the stud manipulator, gas is removed from the stud manipulator to remove contaminants from the vicinity of the seal.

14. The method of claim 12, wherein a seal is provided around each stud manipulator, and after gas is delivered to the stud manipulator, gas is removed from the stud manipulator to remove contaminants from the vicinity of the seal.

15. 15. The method of any one of claims 11 to 14, further comprising heating the stud using a heater in the stud manipulator to harden the glue.

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