Reticle handler apparatus, lithographic apparatus including reticle handler apparatus, and method

Abstract

Embodiments herein describe methods, devices, and systems for a reticle gripper. The disclosure provides a reticle handler apparatus comprising: a reticle handler. At least one reticle handler arm comprising: a static structure that is connected to the reticle handler, an end part for holding a reticle, a spring-damper system connecting the end part to the static structure, and a locking mechanism having a first or locked position. The end part is substantially fixated with respect to the static structure and a second or unlocked position. The end part is able to move within a predetermined range with respect to the static structure.

Description

RETICLE HANDLER APPARATUS. LITHOGRAPHIC APPARATUS INCLUDING RETICLE HANDLER APPARATUS. AND METHODCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority of US application 63 / 710,127 which was filed on October 22, 2024 and which is incorporated herein in its entirety by reference.FIELD

[0002] The present disclosure relates to a reticle handler apparatus, a lithographic apparatus including a reticle handler apparatus, and a method for handling reticles. The reticle is for instance suitable to impart a pattern to radiation in lithographic processes and systems.BACKGROUND

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

[0004] To project a pattern on a substrate a lithographic apparatus may use electromagnetic radiation. The wavelength of this radiation determines the minimum size of features, which can be formed on the substrate. A lithographic apparatus, which uses extreme ultraviolet (EUV) radiation, having a wavelength within the range 4-20 nm, for example 6.7 nm or 13.5 nm, may be used to form smaller features on a substrate than a lithographic apparatus which uses, for example, radiation with a wavelength of 193 nm.

[0005] Reticles are critical and sensitive components for imparting patterns on substrates. Reticles contain the chip pattern to be printed on the substrate. A reticle handler may be used to move and position reticles for scanning and / or patterning operations in a lithographic apparatus. Input disturbances in the reticle handler may put the reticle at risk of slipping, sliding, and generating particles, which may end up on the reticle front-side or back side, causing defects on every die. Furthermore, increased vibrations may lead to blurring and failure of imaging sensors, which are utilized for reticle pre-alignment and particle detection. In EUV lithography, reticles are multilayer reflectors that use interference to reflect light from the pattern.

[0006] EUV systems typically use a reticle handler provided with a robot or a manipulator with a robot gripper to transport reticles within a so-called “EUV inner pod” (EIP). For instance, one or more handlers may be provided to transport reticles between a storage container and a reticle stage inside the lithographic apparatus.

[0007] Given the relative fragility of the reticle, the EUV reticle is relying on gravity and friction with respect to a baseplate of the EIP. Herein, the EIP is positioned on the gripper. In other words, contactbetween the reticle and the baseplate is typically limited to a few interface points along the circumference of the baseplate. To avoid the reticle from slipping off the respective baseplate on the gripper during transport, the acceleration of the gripper holding the baseplate and reticle may not exceed a relatively limited threshold. Said threshold may be referred to as the slip acceleration or slip criterium. Herein, in addition to acceleration initiated by the robot handler itself, acceleration may for instance be influenced by system vibration. As a result, the speed of movement of the handler is further limited with respect to the threshold in order to compensate for potential system vibrations.

[0008] To provide an indication, conventionally, a reload time, indicating the time required to exchange one reticle for another, may typically significantly be on the order of 30 to 60 seconds. Time required to move a reticle from an out-of-vacuum location to an in-vacuum location inside the lithographic apparatus may well exceed 200 seconds, with reload times in vacuum being on the order of 100 to 150 seconds. As reticles may need to be exchanged regularly, typically on the order of 100 to 200 times per day per lithographic apparatus, these exchange times render the reticle exchange a significant constraint in the lithographic process.

[0009] The semiconductor industry is continuously trying to increase the throughput, i.e. the speed of processing. Increased throughput however often also involves increased mechanical vibrations. To limit the impact of increased system vibrations on the gripper, and thereby on the reticle in the EIP, the industry came up with dynamically isolated grippers. However, a disadvantage of dynamically isolated grippers with respect to static grippers is that the speed and acceleration settings of the gripper actually need to be limited in order to avoid damage to the dynamically isolated grippers itself. The restricted speed settings negatively impact reticle reload times, as well as the time to transfer reticles from an atmospheric environment to vacuum and vice versa, and consequently reduce the number of wafers which can be processed per unit of time. Thus, even though these dynamically isolated grippers improve the slip criterium, overall, dynamically isolated grippers may actually reduce throughput.SUMMARY

[0010] The present disclosure aims to provide a gripper system obviating one or more of the disadvantages as outlined above.

[0011] Accordingly, the present disclosure provides a reticle handler apparatus comprising:a reticle handler;at least one reticle handler arm, comprising:a static structure that is connected to the reticle handler;a end part for holding a reticle;a spring-damper system connecting the end part to the static structure; anda locking mechanism having a first position, wherein the end part is substantially fixated with respect to the static structure, and a second position, wherein the end part is able to move within a predetermined range with respect to the static structure.

[0012] In an embodiment, the locking mechanism comprises a moveable pen and corresponding opening.

[0013] In an embodiment, the locking mechanism comprises a moveable wedge and corresponding opposite wedge.

[0014] In an embodiment, the locking mechanism comprises one or more rotatable arms connected to the static structure, the rotatable arms having an end provided with a brake for engaging or disengaging the end part.

[0015] In an embodiment, the locking mechanism comprises an electro magnet adapted to use attractive force to arrive in the first position.

[0016] In an embodiment, the locking mechanism comprises an electro magnet adapted to use repulsive force to arrive in the first position.

[0017] In an embodiment, the spring-damper system comprises one or more of: eddy current dampers; viscoelastic dampers; a spring; a magnetic system.

[0018] According to another aspect, the disclosure provides a lithographic apparatus comprising: an illumination system configured to condition a radiation beam;a support structure constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam;a projection system configured to project the patterned radiation beam onto a target portion of a substrate, anda reticle handler apparatus comprising:a reticle handler;at least one reticle handler arm comprisinga static structure that is coupled to the reticle handler;an end part for holding a reticle;a spring-damper system connecting the gripper to the static structure; anda locking mechanism having a first position, wherein the end part is substantially fixated with respect to the static structure, and a second position, wherein the end part is able to move within a predetermined range with respect to the static structure.

[0019] In an embodiment, the locking mechanism comprises one or more of:i) a moveable pen and corresponding opening;ii) a moveable wedge and corresponding opposite wedge;iii) one or more rotatable arms having an end provided with a brake for engaging or disengaging the end part;iv) an electro magnet using attractive force to engage the locking position;v) an electro magnet lock using repulsive force to engage the locking position.

[0020] In an embodiment, wherein, when the locking mechanism is in the second position, the end part is configured to provide passive isolation and damping by using mass of the patterning device, the end part, and a reticle baseplate to provide an isolating structure for reducing vibrations in the patterning device.

[0021] In an embodiment, wherein the spring-damper system is configured to damp accelerations in the reticle handler apparatus when the locking mechanism is in the second position, and wherein the locking mechanism turns the reticle handler arm into a substantially rigid structure when the locking mechanism is in the first position.

[0022] According to another aspect, the disclosure provides a method of operating a reticle handler apparatus, the method comprising:providing a reticle handler apparatus, the reticle handler apparatus comprising a reticle handler and at least one reticle handler arm arranged to hold the reticle, wherein the at least one reticle handler arm comprises:a static structure that is coupled to the reticle handler;an end part that is coupled to the static structure;a spring-damper system connecting the gripper to the static structure, anda locking mechanism having a first position, wherein the end part is substantially fixated with respect to the static structure, and a second position, wherein the end part is able to move within a predetermined range with respect to the static structure;using the reticle handler apparatus to pick up a reticle at a first location and drop off the respective reticle a second location, thereby:- unlocking the locking mechanism in the first position when at least one end part of at least one reticle handler arm is provided with a reticle; and- locking the locking mechanism in the second position when none of the at least one reticle handler arm is provided with a reticle.

[0023] In an embodiment, the locking mechanism comprises one or more of:i) a moveable pen and corresponding opening;ii) a moveable wedge and corresponding opposite wedge;iii) one or more rotatable arms having an end provided with a brake for engaging or disengaging the end part;iv) an electro magnet adapted to fixate the end part in the first position using attractive force; andv) an electro magnet adapted to fixate the end part in the first position using repulsive force).

[0024] Further features of the disclosure, as well as the structure and operation of various embodiments of the disclosure, are described in detail below with reference to the accompanying drawings. It is noted that the disclosure is not limited to the specific embodiments described herein. Such embodiments arepresented herein for illustrative purposes only. Additional embodiments will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the present disclosure and, together with the description, further serve to explain the principles of the disclosure and to enable a person skilled in the relevant art(s) to make and use the disclosure. Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying schematic drawings, in which:

[0026] FIG. 1 shows a schematic illustration of a lithographic apparatus, according to some embodiments.

[0027] FIG. 2 shows a perspective schematic illustration of a reticle stage, according to some embodiments.

[0028] FIG. 3 shows a top plan view of the reticle stage of Figure 2.

[0029] FIG. 4 shows a perspective schematic illustration of an exemplary reticle exchange apparatus.

[0030] FIG. 5 shows a partial cross-sectional view of the reticle exchange apparatus of FIG. 4.

[0031] FIG. 6 shows a schematic illustration of an exemplary reticle exchange apparatus.

[0032] FIG. 7 shows a schematic illustration of an exemplary reticle gripper in a reticle exchange area.

[0033] FIGS. 8A-8D show schematic illustrations of exemplary components of a reticle gripper.

[0034] FIGS. 9A to 9H schematically show side views of respective embodiments of a gripper according to the present disclosure.

[0035] Fig. 10 shows a diagram exemplifying steps in a method according to an embodiment.

[0036] The features of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and / or structurally similar elements. Additionally, generally, the leftmost digit(s) of a reference number identifies the drawing in which the reference number first appears. Unless otherwise indicated, the drawings provided throughout the disclosure should not be interpreted as to-scale drawings.DETAILED DESCRIPTION

[0037] This specification discloses one or more embodiments that incorporate the features of this disclosure. The disclosed embodiment(s) merely exemplify the disclosure. The scope of the disclosure is not limited to the disclosed embodiment(s). The disclosure is defined by the claims appended hereto.

[0038] The embodiment(s) described, and references in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” etc., indicate that the embodiment(s) described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include theparticular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is understood that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0039] Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “on,” “upper” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.

[0040] The term “about” as used herein indicates the value of a given quantity that can vary based on a particular technology. Based on the particular technology, the term “about” can indicate a value of a given quantity that varies within, for example, 10-30% of the value (e.g., ±10%, ±20%, or ±30% of the value).

[0041] Embodiments of the disclosure may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the disclosure may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium may include read only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; electrical, optical, acoustical or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.), and others. Further, firmware, software, routines, and / or instructions may be described herein as performing certain actions. However, it should be appreciated that such descriptions are merely for convenience and that such actions in fact result from computing devices, processors, controllers, or other devices executing the firmware, software, routines, instructions, etc., and in doing that may cause actuators or other devices to interact with the physical world.

[0042] The following applications are incorporated by reference herein in their entireties.

[0043] US 20200075373 Al discloses an apparatus configured to load or unload a mask pod, the apparatus comprising: a load port; and a first load port supporter attached to a first comer of the load port, wherein the first load port supporter comprises at least portions of an L-shaped rectangular prism and protrudes above an upper surface of the load port. Herein, the first load port supporter comprises a first material with a first hardness, and the load port comprises a second material with a second hardness, wherein the first hardness is larger than the second hardness.

[0044] KR102499199 discloses a light cover box gripper for gripping an EUV light cover box, wherein the light cover box gripper comprises: a driving part; a pair of frames connected to both sides of thedriving part; a pair of gripping parts disposed in the frame facing each other; and a rotating part connected to one side of the driving part, wherein the gripping part has four gripping regions, and the gripping regions respectively hold the component parts of the decomposed EUV light cover box. The gripper comprises a clamping part which comprises a first clamping part and a first clamping area and a second clamping area for clamping the inner photomask box; and a second clamping part and a third clamping area and a fourth clamping area for clamping the outer photomask box. Herein, the driving part drives the pair of frames in a straight line direction. The first clamping portion and the second clamping portion have a structure for absorbing an impact when clamping the EUV photomask case.

[0045] US 20200335362 Al discloses a gripping unit, comprising: a gripping arm for gripping a reticle pod; and at least two gripping modules, each of said at least two gripping modules deposed on an end of said gripping arm for passing through said reticle pod; wherein each of said at least two gripping modules comprises a case extending inside to outside of said reticle pod, a stopper configured in said case and passing through said reticle pod and a spring unit connected with said stopper; wherein said spring unit is used to restore a position of said stopper.

[0046] Despite these disclosures, the respective devices may exhibit deficiencies with respect to ability to dealing with system vibrations. For example, to obviate damage to device parts and at the same time obviate slip of the reticle or mask, acceleration of the gripper is still limited.

[0047] Before describing such embodiments in more detail, however, it is instructive to present an example environment in which embodiments of the present disclosure may be implemented.

[0048] Exemplary Lithographic System

[0049] FIG. 1 shows a lithographic system comprising a radiation source SO and a lithographic apparatus LA. The radiation source SO is configured to generate an EUV radiation beam B and to supply the EUV radiation beam B to the lithographic apparatus LA. The lithographic apparatus LA comprises an illumination system IL, a support structure MT configured to support a patterning device MA (e.g., a mask), a projection system PS, and a substrate table WT configured to support a substrate W.

[0050] The illumination system IL is configured to condition the EUV radiation beam B before the EUV radiation beam B is incident upon the patterning device MA. Thereto, the illumination system IL can include a faceted field mirror device 10 and a faceted pupil mirror device 11. The faceted field mirror device 10 and faceted pupil mirror device 11 together provide the EUV radiation beam B with a desired cross-sectional shape and a desired intensity distribution. The illumination system IL can include other mirrors or devices in addition to, or instead of, the faceted field mirror device 10 and faceted pupil mirror device 11.

[0051] After being thus conditioned, the EUV radiation beam B interacts with the patterning device MA. As a result of this interaction, a patterned EUV radiation beam B’ is generated. The projection system PS is configured to project the patterned EUV radiation beam B’ onto the substrate W. Forthat purpose, the projection system PS can comprise a plurality of mirrors 13, 14 that are configured toproject the patterned EUV radiation beam B’ onto the substrate W held by the substrate table WT. The projection system PS can apply a reduction factor to the patterned EUV radiation beam B’, thus forming an image with features that are smaller than corresponding features on the patterning device MA. For example, a reduction factor of 4 or 8 can be applied. Although the projection system PS is illustrated as having only two mirrors 13, 14 in FIG. 1, the projection system PS can include a different number of mirrors (e.g. six or eight mirrors).

[0052] The substrate W can include previously formed patterns. Where this is the case, the lithographic apparatus LA aligns the image, formed by the patterned EUV radiation beam B’, with a pattern previously formed on the substrate W.

[0053] A relative vacuum, i.e. a small amount of gas (e.g. hydrogen) at a pressure well below atmospheric pressure, can be provided in the radiation source SO, in the illumination system IL, and / or in the projection system PS.

[0054] The radiation source SO can be a laser produced plasma (LPP) source, a discharge produced plasma (DPP) source, a hydrogen plasma source, a free electron laser (FEL), or any other radiation source that is capable of generating EUV radiation.

[0055] Exemplary Reticle Stage

[0056] FIGS. 2 and 3 show schematic illustrations of an exemplary reticle stage 200, according to some embodiments. Reticle stage 200 can include top stage surface 202, bottom stage surface 204, side stage surfaces 206, and clamp 300. In some embodiments, reticle stage 200 with clamp 300 can be implemented in lithographic apparatus LA. For example, reticle stage 200 can be support structure MT in lithographic apparatus LA. In some embodiments, clamp 300 can be disposed on top stage surface 202. For example, as shown in FIG. 2, clamp 300 can be disposed at a center of top stage surface 202 with clamp frontside 302 facing perpendicularly away from top stage surface 202.

[0057] In some lithographic apparatuses, for example, lithographic apparatus LA, a reticle stage 200 with a clamp 300 can be used to hold and position a reticle 408 for scanning or patterning operations. In one example, the reticle stage 200 can require powerful drives, large balance masses, and heavy frames to support it. In one example, the reticle stage 200 can have a large inertia and can weigh over 500 kg to propel and position a reticle 408 weighing about 0.5 kg. To accomplish reciprocating motions of the reticle 408, which are typically found in lithographic scanning or patterning operations, accelerating and decelerating forces can be provided by linear motors that drive the reticle stage 200.

[0058] In some embodiments, as shown in FIGS. 2 and 3, reticle stage 200 can include first encoder 212 and second encoder 214 for positioning operations. For example, first and second encoders 212, 214 can be interferometers. First encoder 212 can be attached along a first direction, for example, a transverse direction (i.e., X-direction) of reticle stage 200. And second encoder 214 can be attached along a second direction, for example, a longitudinal direction (i.e., Y-direction) of reticle stage 200. In some embodiments, as shown in FIGS. 2 and 3, first encoder 212 can be orthogonal to second encoder 214.

[0059] As shown in FIGS. 2 and 3, reticle stage 200 can include clamp 300. Clamp 300 is configured to hold reticle 408 in a fixed plane on reticle stage 200. Clamp 300 includes clamp frontside 302 and can be disposed on top stage surface 202. In some embodiments, clamp 300 can use mechanical, vacuum, electrostatic, or other suitable clamping techniques to hold and secure an object. In some embodiments, clamp 300 can be an electrostatic clamp, which can be configured to electrostatically clamp (i.e., hold) an object, for example, reticle 408 in a vacuum environment. Due to the requirement for EUV radiation to perform in a vacuum environment, vacuum clamps cannot be used to clamp a mask or reticle and instead electrostatic clamps can be used. For example, clamp 300 can include an electrode, a resistive layer on the electrode, a dielectric layer on the resistive layer, and burls projecting from the dielectric layer. In use, a voltage can be applied to clamp 300, for example, several kV. And current can flow through the resistive layer, such that the voltage at an upper surface of the resistive layer will substantially be the same as the voltage of the electrode and generate an electric field. Also, a Coulomb force, attractive force between electrically opposite charged particles, will attract an object to clamp 300 and hold the object in place. In some embodiments, clamp 300 can be a rigid material, for example, a metal, a dielectric, a ceramic, or a combination thereof.

[0060] Exemplary Reticle Exchange Apparatus

[0061] FIGS. 4 through 6 show schematic illustrations of an exemplary reticle exchange apparatus 100, according to some embodiments. Reticle exchange apparatus 100 can be configured to minimize reticle exchange time, particle generation, and contact forces or stresses from clamp 300 and / or reticle 408 to reduce damage to clamp 300 and reticle 408 and increase overall throughput in a reticle exchange process, for example, in a lithographic apparatus LA.

[0062] As shown in FIGS. 4 and 5, reticle exchange apparatus 100 can include reticle stage 200, clamp 300, and in-vacuum robot 400. In-vacuum robot 400 can include reticle handler 402.

[0063] In some embodiments, reticle handler 402 can be a rapid exchange device (RED), which is configured to efficiently rotate and minimize reticle exchange time. For example, reticle handler 402 can save time by moving multiple reticles from one position to another substantially simultaneously, instead of serially.

[0064] In some embodiments, as shown in FIG. 4, reticle handler 402 can include one or more reticle handler arms 404. In some embodiments, reticle handler arms 404 may be referred to herein as rapid exchange device (RED) grippers. Reticle handler arm 404 can include reticle baseplate 406. Reticle baseplate 406 can be configured to hold an object, for example, reticle 408. In some embodiments, reticle baseplate 406 may be referred to herein as a reticle base frame.

[0065] In some embodiments, reticle baseplate 406 can be an extreme ultraviolet inner pod (EIP) for a reticle. In some embodiments, reticle baseplate 406 includes reticle baseplate frontside 407, and reticle 408 includes reticle backside 409.

[0066] In some embodiments, as shown in FIGS. 4 and 5, reticle baseplate 406 can hold reticle 408 such that reticle baseplate frontside 407 and reticle backside 409 each face top stage surface 202 andclamp frontside 302. For example, reticle baseplate frontside 407 and reticle backside 409 can be facing perpendicularly away from top stage surface 202 and clamp frontside 302.

[0067] As shown in FIG. 5, reticle exchange apparatus 100 can include reticle exchange area 410, which is the cross-sectional area between clamp 300, reticle 408, reticle baseplate 406, and reticle handler arm 404 during a reticle exchange process.

[0068] In some embodiments, as shown in FIG. 4, reticle handler arms 404 can be arranged symmetrically about reticle handler 402. For example, reticle handler arms 404 can be spaced from each other by about 90 degrees, 120 degrees, or 180 degrees. In some embodiments, reticle handler arms 404 can be arranged asymmetrically about reticle handler 402. For example, two reticle handler arms 404 can be spaced from each other by about 135 degrees, while another two reticle handler arms 404 can be spaced from each other by about 90 degrees.

[0069] In one example, during a reticle exchange process, reticle handler arm 404 of reticle handler 402 positions reticle 408 on reticle baseplate 406 towards clamp 300 in reticle exchange area 410. As described above, a reticle handoff from reticle handler 402 to clamp 300 includes an unknown reticle position offset, which includes a reticle vertical distance offset (i.e., Z-direction offset) and a reticle tilt offset (i.e., Rx offset and Ry offset). Tilt or excessive non-alignment between clamp 300 and reticle 408 can be a source of particle generation and can damage reticle 408 or clamp 300 over time. Reticle backside 409 and clamp frontside 302 should be in coplanar alignment for a final handoff. Despite calibration, variations still exist due to reticle mechanical and positioning tolerances, which can lead to high comer impacts and unpredictable first contact points between clamp 300 and reticle 408.

[0070] In one example, the reticle exchange process can involve lowering reticle stage 200 with clamp 300, which starts far away from reticle handler 402, as close to reticle 408 as possible until clamp 300 contacts reticle 408 to account for all possible offsets and / or tilts. During a reticle exchange process, reticle stage 200 with clamp 300 can be adjusted in a multi-stage movement.

[0071] As shown in FIG. 6, reticle exchange apparatus 100 can include clamp 300, reticle 408, and reticle baseplate 406. The multi-stage movement can occur in four stages: (1) approach; (2) first contact; (3) full contact; and (4) voltage applied to clamp.

[0072] Clamp 300 can be adjusted in a substantially vertical direction (i.e., Z-direction) toward reticle backside 409. In approach configuration 20, clamp 300 is turned off (i.e., no applied voltage) and reticle handler 402 deactivates the vertical direction (i.e., Z-direction) and tilt (i.e., Rx and Ry, rotation about X-direction and rotation about Y -direction, respectively) servo motors (not shown) of reticle handler arm 404 in reticle exchange area 410.

[0073] Clamp 300 can be adjusted in a substantially vertical direction (i.e., Z-direction) toward reticle backside 409 until clamp 300 makes contact with reticle backside 409. In first contact configuration 30, clamp 300 is turned off and clamp 300 makes contact with reticle backside 409, for example, a comer of reticle 408, and then rotates or tilts about the contact (i.e., Rx and Ry).

[0074] Reticle exchange apparatus 100 can be in a full contact configuration. Herein, clamp 300 can be rotationally adjusted about the contact (i.e., Rx and Ry) toward reticle backside 409 until clamp 300 makes full contact with reticle backside 409. In full contact configuration 40, clamp 300 is turned off and clamp 300 makes full contact with reticle backside 409, for example, all four comers of reticle 408, and is coplanar with reticle backside 409.

[0075] In some embodiments, as shown in FIG. 5, reticle exchange apparatus 100 can include clamp controller 360. Clamp controller 360 can be coupled to clamp 300 and be configured to control a position of clamp 300. For example, clamp controller 360 can be configured to control reticle stage 200 to allow compliant movement of clamp 300.

[0076] In some embodiments, clamp controller 360 can be coupled to servo motors or servo actuators (i.e., X-direction, Y-direction, Z-direction, Rx, Ry, Rz) of reticle stage 200 and / or clamp 300. For example, clamp controller 360 can control translations of reticle stage 200 with clamp 300 along an x-axis, y-axis, and z-axis (i.e., X-direction, Y-direction, Z-direction) and rotations about the x-axis, y-axis, and z-axis (i.e., Rx, Ry, Rz), where the x-axis, y-axis, and z-axis are orthogonal coordinates.

[0077] Exemplary Reticle Gripper Apparatuses

[0078] A reticle is a critical and sensitive component for imparting patterns on a substrate. Components in a reticle handler may be subject to input disturbances that may result in slippage of the reticle and / or failure to meet reticle positioning requirements for scanning or patterning operations. This may result in particle generation and contamination of the reticle, potential reticle / clamp damage, and / or blurring of imaging sensors. Thus, it may be desirable to reduce input disturbances (e.g., vibrations) to the reticle handler in lithographic apparatuses and systems, in order to improve throughput and performance.

[0079] In some embodiments, various dampers such as tune mass dampers, active dampers, and / or seismic dampers are utilized to reduce the impact of external and self-generated vibrations in lithographic apparatuses.

[0080] In some embodiments, tune mass dampers may be used to reduce the effect of a particular structural mode. Tune mass dampers may be unidirectional. Thus, custom designed dampers may be desirable per degree of freedom of interest and vibration mode of interest. In some embodiments, a tune mass damper may be used to attenuate the effect of vibrations in two orthogonal directions with decreased efficiency, such as by placing the tune mass damper at 45° from two degrees of freedom (DOF). Tune mass dampers may be tuned to specific frequencies and robust in fixed resonance configurations (e.g., in parallel robots in a reticle exchange device) and less robust in non-fixed resonance configurations (e.g., in serial robots such as out-of- vacuum robots (OVR) and in-vacuum robots (IVR)).

[0081] In some embodiments, active dampers may be utilized to reduce the effect of several structural vibration modes. Active dampers may require power and, in some cases, an external measurement of the excitation. In some embodiments, active dampers may be configured to attenuate one degree offreedom, but as described above with tune mass dampers, active dampers may be used to attenuate two degrees of freedom simultaneously.

[0082] In some embodiments, seismic dampers may be used to attenuate a broad spectrum with less efficiency than tune mass dampers. Seismic dampers may attenuate 2 or more degrees of freedom depending on the configuration. Other embodiments include structural damping, which adds damping elements to a structure, and module isolation, in which a complete module is isolated to mitigate input disturbances.

[0083] In some aspects, module isolation approaches may be complex and may necessitate the module being balanced for retaining a center of gravity. However, making sure the center of gravity is retained in the same place may be challenging, particularly for robots in which the center of gravity changes during robot operation. Active isolation approaches may also allow for accurate measurements of input vibrations, as well as additional active components (such as wires, sensors, and the like), which may add extra complexity to the system. Tune mass dampers might also not be robust for robots at all positions due to changes in the center of gravity. Furthermore, other damping strategies may be difficult to implement as result of volume and performance constraints in the system.

[0084] Thus, the present disclosure introduces passive isolation and damping utilizing the mass of the reticle and reticle baseplate (e.g., EIP) to create an isolated structure to mitigate external, structural and self-generated vibrations to the reticle (e.g., directly at the point of interest) and thus avoiding contamination or reticle damage issues.

[0085] In some embodiments, damping may be used to maintain the displacement of the reticle due to internal and external accelerations within specifications even though the reticle is mounted on a soft structure. In some embodiments, damping may be optimized by introducing eddy current dampers and / or viscoelastic materials (e.g., Viton, synthetic rubbers, fluoropolymer elastomers, and / or the like) that are configured to compensate and eliminate any creep effects. In some embodiments, selection of the damping method (e.g., viscoelastic material, eddy current dampers, or the like) and use of flexures, airbearings, and / or springs may be a function of the isolation specifications, load, and positioning tolerances.

[0086] In some embodiments, the reticle gripper damper and isolation system provide a compact and passive solution, in which the system may be implemented in a small volume without additional cooling, power, or other servo control-related feature for implementation. In some embodiments, the system is flexible for meeting conflicting constraints, such as providing isolation and positioning simultaneously. The system also allows for vibration attenuation in up to three perpendicular directions, which might not be feasible by using a different approach (e.g., using tune mass dampers and active isolation approaches).

[0087] FIG. 7 shows a schematic illustration of a reticle gripper 450 in reticle exchange area 410, according to some embodiments. Reticle exchange area 410 includes reticle handler 402 with two reticle handler arms 404. Reticle handler arms 404 can support a reticle baseplate 406 that is configured tohold a reticle 408. Although only two reticle handler arms 404 are shown in FIG. 7, it should be appreciated that any number of reticle handler arms 404 may be used in reticle handler 402. Each reticle handler arm 404 also includes reticle gripper 450, which may be arranged between reticle handler 402 and the reticle baseplate 406. In some embodiments, the reticle handler arm 404 and reticle gripper 450 may be referred to as an end effector.

[0088] In some embodiments, reticle gripper 450 may be utilized to provide passive isolation and damping to attenuate any induced motions or vibrations occurring during reticle exchange and / or reticle handling operations, as further discussed below with reference to FIGS. 8A-8D. In some embodiments, reticle gripper 450 may be attached to reticle handler 402 and / or reticle baseplate 406 using pins, screws, bolts, and / or fasteners. Although FIG. 7 shows reticle gripper 450 in a particular configuration, it should be appreciated that reticle gripper 450 may be designed with any number of flexures, pins, and springs.

[0089] FIGS. 8A-8D show schematic illustrations of components of reticle gripper 450, according to some embodiments. In some embodiments, FIGS. 8A-8D show components of reticle gripper 450 disassembled and disconnected from reticle handler 402 for illustrative purposes.

[0090] In some embodiments, reticle gripper 450 comprises a static structure 452 and an isolation structure 454. In particular, FIG. 8A illustrates static structure 452 of reticle gripper 450, whereas FIG.8B illustrates isolation structure 454 of reticle gripper 450. In some embodiments, static structure 452 and isolation structure 454 may be referred to herein as static mass and isolation mass, respectively.

[0091] In some embodiments, static structure 452 may comprise a rigid structure that is formed by machining processes. In some embodiments, static structure 452 may be coupled to (e.g., bolted down to) the reticle handler 402. Static structure 452 may also be connected to a flexure structure 453. Flexure structure 453 may be referred to as a flexure mass and may comprise a flexible element that is designed to provide specific degrees of freedom to the system. In some embodiments, flexure structure 453 may move independently of static structure 452 at its own frequency.

[0092] In some embodiments, isolation structure 454 includes a strain gauge 457 and eddy current dampers 456, which may be housed in cube-shaped locations of the isolation structure 454. In some embodiments, strain gauge 457 may be referred to as a moving mass and may measure strain of the isolation structure 454.

[0093] In some embodiments, eddy current dampers 456 may comprise a cobalt iron alloy. An example eddy current damper 456 is shown separate from isolation structure 454 at the bottom of FIG. 8B for illustrative purposes. Each eddy current damper 456 may include magnets 462, which are housed or sealed in the dampers 456. The magnets 462 may enclose or surround a stainless steel conductor in order to provide damping effects. When there is a relative velocity or acceleration between the conductor and the magnets 462, an eddy current is induced such that the eddy current and magnetic fields impede the relative movement. In other words, when the conductors move inside the eddy current dampers 456, the change in magnetic field causes damping. Thus, an eddy current damping effect or force may be generated within the gripper damper.

[0094] In some embodiments, two eddy current dampers 456 may be utilized to provide damping effects, and each eddy current damper 456 may comprise dimensions of about 22 mm x 22 mm x 16.2 mm.

[0095] In some embodiments, isolation structure 454 may be designed to have a resonant frequency of about 7 Hz in the horizontal (X,Y) directions with greater than about 6% damping. In some embodiments, the isolation structure 454 may be designed as a flexure system with individual flexures with dimensions of about 22 mm x 10 mm x 0.170 mm. In some embodiments, the 0.170 mm thickness of the flexures may approach limits of current manufacturing technologies. Eddy current dampers may be selected as the damping elements of reticle gripper 450 in order to increase the thickness, apportion as much stiffness to the flexures as possible, and avoid issues related to creep. In some embodiments, horizontal reticle acceleration in the reticle handler may be reduced from 10.8 m / s2to 0.24 m / s2. This reduction in acceleration may provide a margin of safety against slip of 1.8, in which the reticle is expected to slip for any value less than 1. In some embodiments, the passive isolation and damping system may allow robot handoff budgets and image blur specifications to be met.

[0096] Static structure 452 and isolation structure 454 may be assembled together as shown in FIGS.8C and 8D. In particular, FIG. 8C shows static structure 452 affixed to isolation structure 454, in which the flexure structure 453 fits on top of the square-shaped piece of the isolation structure 454. Eddy current dampers 456 are also shown connected to corresponding portions of the static structure 452. In some embodiments, a plurality of springs may join the flexure structure 453 and the static structure 452 together. The frequency of the reticle gripper may depend on the mass and stiffness of the springs. FIG.8D shows a bottom plan view of the assembled reticle gripper 450 with both static structure 452 and isolation structure 454.

[0097] Embodiments

[0098] According to the present disclosure, a reticle handler apparatus comprising a reticle handler 402 as exemplified above can be improved as described herein below. Please note that the reticle handler can be any reticle handler, including but not limited to a rapid exchange device, an in-vacuum robot, an out-of-vacuum robot.

[0099] Generally referring to FIGS. 9A to 9H, the reticle handler 402 comprises at least one, but typically more, reticle handler arms 404. The handler arm comprises a static structure 452 that is connected to the reticle handler. Said connection is typically relatively rigid. The arm also comprises an end part 454 for holding a reticle. A spring-damper system 902 connects the end part 454 to the static structure 452. The spring-damper system is exemplified herein above using the eddy current damper 456 (Fig. 8B). The end part 454 can be isolated from movement of the static structure 452 by the springdamper system 902. In a practical embodiment, the spring-damper system may typically be designed to isolate the end part with respect to vibrations (movement) of the static structure within a certain range. Said range may include a predetermined range of motion. Said range may also include a frequency range for which the spring-damper system 902 is optimized.

[0100] According to the disclosure, the arm 404 comprises a locking mechanism 900. The locking mechanism 900 has a first or locked position, wherein the locking mechanism engages the end part 454. Herein, the end part 454 is substantially fixated with respect to the static structure 452. The locking mechanism has a second or unlocked position, wherein the locking mechanism is disengaged from the end part 454. Herein, the end part 454 is able to move with respect to the static structure within said range as enabled by the spring-damper system 902.

[0101] Generally referring to Fig. 9A, in an embodiment, the locking mechanism 900 comprises a peg or pen 904 provided on either one of the static structure 452 or the end part 454. The other of the static structure 452 or end part 454 is provided with a corresponding opening 906 able to receive the peg. The peg is moveable between the locked position, wherein the peg is engaged in the opening 906, and the unlocked position, wherein the peg is disengaged from the opening 906. Either the peg 904 or the opening 906 may be movable towards and away from the opposite part. The moveable part is, preferably, connected to or provided as an integral part of the static structure or the reticle handler. Please note that although the peg 904 is shown to be aligned with the end part 454, the peg 904 and the corresponding opening may also be arranged perpendicular to the end part 454.

[0102] Generally referring to Fig. 9B, in another embodiment, the locking mechanism 900 comprises a wedge mechanism 910. The wedge mechanism 910 comprises a first wedge part 912 connected to the static structure 452 and a corresponding second wedge part 914 connected to the end part 454. The first and second wedge parts may be either a single wedge, or a symmetric double sided wedge (as shown in Fig. 9B). Typically, the first wedge part 912 connected to the static structure may be moveable towards and away from the second wedge part 914. In the locked position, the first wedge part 912 engages the second wedge part 914, thereby fixating the second wedge with respect to the first wedge. In the unlocked position, the first wedge part disengages the second wedge part 914.

[0103] Generally referring to Fig. 9C, in an embodiment, the locking mechanism 900 comprises at least one moveable pen 920 having an end 922 for engaging the end part 454. Herein, the end 922 may be provided with a material suitable for gripping, engaging, and holding the end part 454. Said material may include, but is not limited to, an elastomer or rubber, steel having a surface treatment to provide a roughened surface, etc. Typically, the pen 920 is connected to the static structure 452 and is moveable towards and away from the end part 454. In the locked position, the end 922 of the pen 920 engages the end part 454, thereby fixating the end part 454 with respect to the pen, and thus to the static structure 452. In the unlocked position, the end 922 of the pen 920 disengages the end part 454. The moveable pen 920 has many conceivable variations, such as pneumatic, servo controlled, controller via voice coil, etc.

[0104] Generally referring to Fig. 9D, in an embodiment, the locking mechanism 900 comprises at least one hinging mechanism. The hinging mechanism comprises a lock arm 930 connected to the static structure 452 using a hinge or pivot 932. The lock arm 930 has a lock end 934 for engaging the end part 454. Herein, the lock end 934 may be provided with a material suitable for gripping, engaging, andholding the end part 454. The lock arm 930 is connected to the static structure 452 and can pivot towards and away from the end part 454. In the locked position, the lock end 934 of the arm 930 engages the end part 454, thereby fixating the end part 454 with respect to the lock arm 930, and thus to the static structure 452. In the unlocked position, the lock end 934 of the lock arm 930 disengages the end part 454.

[0105] Generally referring to Fig. 9E, in an embodiment, the locking mechanism 900 comprises at least one squeeze brake mechanism 940. The squeeze brake mechanism 940 may comprises one or more lock arms 942 connected to the static structure 452 using a hinge or pivot 945. The lock arms 942 have a lock end 944 for engaging the end part 454. Herein, the lock end 944 may be provided with a material suitable for gripping, engaging, and holding the end part 454. The lock arms 942 may be spring loaded, wherein a default position is the unlocked position. An actuator may be provided to overcome the spring pre-load to squeeze and pivot the arms 942 to engage the end part 454. Thus, the ends 944 of the arms 942 can pivot towards and away from the end part 454. In the locked position, the end 944 of the arm 942 engages the end part 454, thereby fixating the end part 454 with respect to the lock arm 942, and thus to the static structure 452. In the unlocked position, the lock end 944 of the lock arm 942 disengages the end part 454.

[0106] Generally referring to Fig. 9F, in an embodiment, the locking mechanism 900 comprises at least one rotatable lock element 950. The rotatable lock element 950 may be connected to the static structure 452 using a hinge or pivot 952. The rotatable lock element 950 has one or more lock ends 954, 956 for engaging the end part 454. Herein, the lock end 954, 956 may be provided with a material suitable for gripping, engaging, and holding the end part 454. The rotatable lock element 950 may be spring loaded, wherein a default position is the unlocked position. An actuator may be provided to overcome the spring pre-load to rotate the rotatable lock element 950 until the ends 954, 956 engage the end part 454. Thus, the ends 954, 956 of the rotatable lock element 950 can rotate towards and away from the end part 454. In the locked position, the ends 954, 956 of the rotatable lock element 950 engage the end part 454, thereby fixating the end part 454 with respect to the rotatable lock element 950, and thus to the static structure 452. In the unlocked position, the ends 954, 956 of the rotatable lock element 950 disengage the end part 454.

[0107] Generally referring to Fig. 9G, in an embodiment, the locking mechanism 900 comprises at least one rotatable lock arm 960. The lock arm 960 may be connected to the static structure 452 or to another part of the reticle handler via a hinge or pivot 962. The end part 954 may be provided with a landing pad 964 for engaging the lock arm 960. Herein, the pad 964 may be provided with a material suitable for gripping, engaging, and holding the arm 464. The rotatable lock arm 960 may be spring loaded, wherein a default position is either the locked position or the unlocked position. An actuator may be provided to overcome the spring pre-load to rotate the arm to the other position, i.e. either the unlocked position or the locked position. The rotatable lock arm can rotate towards and away from the end part 454 until the arm 960 engages the end part 454. In the locked position, the arm 960 engagesthe landing pad 964 of the end part 454, thereby fixating the end part 454 with respect to the rotatable lock arm 960, and thus to the static structure 452. In the unlocked position, the lock arm 960 disengages the end part 454.

[0108] Generally referring to Fig. 9H, in an embodiment, the locking mechanism 900 comprises a magnetic mechanism 970. The magnetic mechanism 970 may comprise one or more first magnets 972 connected to the static structure 452. The magnetic mechanism 970 may comprise one of more second magnets connected to the end part 454. In an embodiment, the second magnets 974 may be permanent magnets. In an embodiment, the first magnets 972 may be electro magnets.

[0109] In the locked position, the first magnets 972 may attract the second magnets 974, thereby fixating the end part 454 with respect to the static structure 452. In the unlocked position, electro current to the first magnets 972 may be lowered or stopped, so that the first magnets substantially do not attract the second magnets 974, thereby allowing the end part 454 to move within an available range of motion.

[0110] In another embodiment, in the locked position, the first magnets 972 may repulse the second magnets 974, thereby fixating the end part 454 with respect to the static structure 452. In the unlocked position, electro current to the first magnets 972 may be lowered or stopped, so that the first magnets substantially do not repulse (not attract) the second magnets 974, thereby allowing the end part 454 to move within an available range of motion.[oni] Method of Operation

[0112] FIG. 10 is a flowchart of an embodiment of a method 1000 for operating a reticle handler apparatus as disclosed herein. The reticle handler apparatus typically includes one or more, typically a few, arms for each holding a reticle. The arms and the reticle handler may be in accordance with any of the examples and embodiments as described above.

[0113] The method typically includes unlocking the locking mechanism in the first of unlocked position when at least one end part of at least one reticle handler arm is provided with a reticle. The method includes the step of locking the locking mechanism in the second or locked position for each arm of the reticle handler, when none of the one or more reticle handler arms of the reticle handler is provided with a reticle . This allows the reticle handler to move relatively fast when no reticle is provided on the reticle handler arms, while allowing the spring-damper system to dampen vibrations and obviate loss of a reticle while one or more of the handler arms are carrying a reticle.

[0114] The method may include a first step 1002 of locking the locking mechanism of each of the one of more arms of a reticle handler in the locked position, when none of the one or more reticle handler arms is provided with a reticle.

[0115] In a second step 1004, one or more of the reticle handler arms are moved towards a reticle pickup location.

[0116] In a third step 1006, one or more of the reticle handler arms pick up a reticle. Substantially at the same time, the locking mechanism of at least the arm which now carries a reticle is unlocked.

[0117] In a fourth step 1008, the one or more reticle handler arms carrying a respective reticle are moved towards a drop-off location.

[0118] In a fourth step 1010, the respective reticles are removed from the respective reticle handler arms and transferred to another piece of equipment or storage container.

[0119] If none of the reticle handler arms of a respective reticle handler carries a reticle, the locking mechanism may, substantially at the same time, be engaged into the locking position.

[0120] The method and system of the present disclosure may reduce reticle reload times with a factor on the order of 10 to 40%.

[0121] Please note that the method and system as disclosed herein are equally applicable for the reticle handler in vacuum as well as for an outer vacuum robot (for transporting reticles from atmospheric pressure to vacuum and vice versa).

[0122] Various embodiments of the present systems and methods are disclosed in the subsequent list of numbered clauses. In the following, further features, characteristics, and exemplary technical solutions of the present disclosure will be described in terms of clauses that may be optionally claimed in any combination:1. A reticle handler apparatus comprising:a reticle handler;at least one reticle handler arm, comprising:a static structure that is connected to the reticle handler;an end part for holding a reticle;a spring-damper system connecting the end part to the static structure; anda locking mechanism having a first position, wherein the end part is substantially fixated with respect to the static structure, and a second position, wherein the end part is able to move within a predetermined range with respect to the static structure.2. The reticle handler apparatus of clause 1, wherein the locking mechanism comprises a moveable pen and corresponding opening.3. The reticle handler apparatus of clause 1, wherein the locking mechanism comprises a moveable wedge and corresponding opposite wedge.4. The reticle handler apparatus of clause 1, wherein the locking mechanism comprises one or more rotatable arms connected to the static structure, the rotatable arms having an end provided with a brake for engaging or disengaging the end part.5. The reticle handler apparatus of clause 1, wherein the locking mechanism comprises an electro magnet adapted to use attractive force to arrive in the first position.6. The reticle handler apparatus of clause 1, wherein the locking mechanism comprises an electro magnet adapted to use repulsive force to arrive in the first position.7. The reticle handler apparatus of clause 1, wherein the spring-damper system comprises one or more of: eddy current dampers; viscoelastic dampers; a spring; a magnetic system.8. A lithographic apparatus comprising:an illumination system configured to condition a radiation beam;a support structure constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam;a projection system configured to project the patterned radiation beam onto a target portion of a substrate, anda reticle handler apparatus comprising:a reticle handler;at least one reticle handler arm comprisinga static structure that is coupled to the reticle handler;an end part for holding a reticle;a spring-damper system connecting the gripper to the static structure; anda locking mechanism having a first position, wherein the end part is substantially fixated with respect to the static structure, and a second position, wherein the end part is able to move within a predetermined range with respect to the static structure.9. The lithographic apparatus of clause 8, wherein the locking mechanism comprises one or more of:i) a moveable pen and corresponding opening;ii) a moveable wedge and corresponding opposite wedge;iii) one or more rotatable arms having an end provided with a brake for engaging or disengaging the end part;iv) an electro magnet using attractive force to engage the first position;v) an electro magnet lock using repulsive force to engage the first position.10. The lithographic apparatus of clause 8, wherein, when the locking mechanism is in the second position, the end part is configured to provide passive isolation and damping by using mass of the patterning device, the end part, and a reticle baseplate to provide an isolating structure for reducing vibrations in the patterning device.11. The lithographic apparatus of clause 8, wherein the spring-damper system is configured to damp accelerations in the reticle handler apparatus when the locking mechanism is in the second position, and wherein the locking mechanism turns the reticle handler arm into a substantially rigid structure when the locking mechanism is in the first position.12. A method of operating a reticle handler apparatus, the method comprising:providing a reticle handler apparatus, the reticle handler apparatus comprising a reticle handler and at least one reticle handler arm arranged to hold the reticle, wherein the at least one reticle handler arm comprises:a static structure that is coupled to the reticle handler;an end part that is coupled to the static structure;a spring-damper system connecting the gripper to the static structure, anda locking mechanism having a first position, wherein the end part is substantially fixated with respect to the static structure, and a second position, wherein the end part is able to move within a predetermined range with respect to the static structure;using the reticle handler apparatus to pick up a reticle at a first location and drop off the respective reticle a second location, thereby:- unlocking the locking mechanism in the first position when at least one end part of at least one reticle handler arm is provided with a reticle; and- locking the locking mechanism in the second position when none of the at least one reticle handler arm is provided with a reticle.13. The method of clause 12, wherein the locking mechanism comprises one or more of:i) a moveable pen and corresponding opening;ii) a moveable wedge and corresponding opposite wedge;iii) one or more rotatable arms having an end provided with a brake for engaging or disengaging the end part;iv) an electro magnet adapted to fixate the end part in the first position using attractive force; andv) an electro magnet adapted to fixate the end part in the first position using repulsive force.

[0123] Although specific reference may be made in this text to a “reticle,” it should be understood that this is just one example of a patterning device and that the embodiments described herein may be applicable to any type of patterning device. Additionally, the embodiments described herein may be used to provide safety support for any object to ensure a clamping failure does not cause the object to fall and damage either itself or other equipment.

[0124] Although specific reference may be made in this text to the use of lithographic apparatus in the manufacture of ICs, it should be understood that the lithographic apparatus described herein may have other applications, such as the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat-panel displays, LCDs, thin-film magnetic heads, etc. The skilled artisan will appreciate that, in the context of such alternative applications, any use of the terms “wafer” or “die” herein may be considered as synonymous with the more general terms “substrate” or “target portion”, respectively. The substrate referred to herein may be processed, before or after exposure, in for example a track unit (a tool that typically applies a layer of resist to a substrate and develops the exposed resist), a metrology unit and / or an inspection unit. Where applicable, the disclosure herein may be applied to such and other substrate processing tools. Further, the substrate may be processed more than once, for example in order to create a multi-layer IC, so that the term substrate used herein may also refer to a substrate that already contains multiple processed layers.

[0125] Although specific reference may have been made above to the use of embodiments of the disclosure in the context of optical lithography, it will be appreciated that the disclosure can be used in other applications, for example imprint lithography, and where the context allows, is not limited to optical lithography. In imprint lithography a topography in a patterning device defines the pattern created on a substrate. The topography of the patterning device can be pressed into a layer of resist supplied to the substrate whereupon the resist is cured by applying electromagnetic radiation, heat, pressure or a combination thereof. The patterning device is moved out of the resist leaving a pattern in it after the resist is cured.

[0126] It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present disclosure is to be interpreted by those skilled in relevant art(s) in light of the teachings herein.

[0127] The term “substrate” as used herein describes a material onto which material layers are added. In some embodiments, the substrate itself can be patterned and materials added on top of it may also be patterned, or may remain without patterning.

[0128] Although specific reference can be made in this text to the use of the apparatus and / or system according to the disclosure in the manufacture of ICs, it should be explicitly understood that such an apparatus and / or system has many other possible applications. For example, it can be employed in the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, LCD panels, thin-film magnetic heads, etc. The skilled artisan will appreciate that, in the context of such alternative applications, any use of the terms “reticle,” “wafer,” or “die” in this text should be considered as being replaced by the more general terms “mask,” “substrate,” and “target portion,” respectively.

[0129] While specific embodiments of the disclosure have been described above, it will be appreciated that the disclosure can be practiced otherwise than as described. The description is not intended to limit the disclosure.

[0130] It is to be appreciated that the Detailed Description section, and not the Summary and Abstract sections, is intended to be used to interpret the claims. The Summary and Abstract sections may set forth one or more but not all exemplary embodiments of the present disclosure as contemplated by the inventor(s), and thus, are not intended to limit the present disclosure and the appended claims in any way.

[0131] The present disclosure has been described above with the aid of functional building blocks illustrating the implementation of specified functions and relationships thereof. The boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed.

[0132] The foregoing description of the specific embodiments will so fully reveal the general nature of the disclosure that others can, by applying knowledge within the skill of the art, readily modify and / oradapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present disclosure. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein.

[0133] The breadth and scope of the present disclosure should not be limited by any of the abovedescribed exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims

CLAIMS1. A reticle handler apparatus comprising:a reticle handler;at least one reticle handler arm, comprising:a static structure that is connected to the reticle handler;an end part for holding a reticle;a spring-damper system connecting the end part to the static structure; anda locking mechanism having a first position, wherein the end part is substantially fixated with respect to the static structure, and a second position, wherein the end part is able to move within a predetermined range with respect to the static structure.

2. The reticle handler apparatus of claim 1 , wherein the locking mechanism comprises a moveable pen and corresponding opening.

3. The reticle handler apparatus of claim 1 , wherein the locking mechanism comprises a moveable wedge and corresponding opposite wedge.

4. The reticle handler apparatus of claim 1, wherein the locking mechanism comprises one or more rotatable arms connected to the static structure, the rotatable arms having an end provided with a brake for engaging or disengaging the end part.

5. The reticle handler apparatus of claim 1, wherein the locking mechanism comprises an electro magnet adapted to use attractive force to arrive in the first position.

6. The reticle handler apparatus of claim 1, wherein the locking mechanism comprises an electro magnet adapted to use repulsive force to arrive in the first position.

7. The reticle handler apparatus of claim 1, wherein the spring -damper system comprises one or more of: eddy current dampers; viscoelastic dampers; a spring; a magnetic system.

8. A lithographic apparatus comprising:an illumination system configured to condition a radiation beam;a support structure constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam;a projection system configured to project the patterned radiation beam onto a target portion of a substrate, anda reticle handler apparatus comprising:a reticle handler;at least one reticle handler arm comprisinga static structure that is coupled to the reticle handler;an end part for holding a reticle;a spring-damper system connecting the gripper to the static structure; anda locking mechanism having a first position, wherein the end part is substantially fixated with respect to the static structure, and a second position, wherein the end part is able to move within a predetermined range with respect to the static structure.

9. The lithographic apparatus of claim 8, wherein the locking mechanism comprises one or more of:a moveable pen and corresponding opening;a moveable wedge and corresponding opposite wedge;one or more rotatable arms having an end provided with a brake for engaging or disengaging the end part;an electro magnet using attractive force to engage the first position;an electro magnet lock using repulsive force to engage the first position.

10. The lithographic apparatus of claim 8, wherein, when the locking mechanism is in the second position, the end part is configured to provide passive isolation and damping by using mass of the patterning device, the end part, and a reticle baseplate to provide an isolating structure for reducing vibrations in the patterning device.

11. The lithographic apparatus of claim 8, wherein the spring-damper system is configured to damp accelerations in the reticle handler apparatus when the locking mechanism is in the second position, and wherein the locking mechanism turns the reticle handler arm into a substantially rigid structure when the locking mechanism is in the first position.

12. A method of operating a reticle handler apparatus, the method comprising:providing a reticle handler apparatus, the reticle handler apparatus comprising a reticle handler and at least one reticle handler arm arranged to hold the reticle, wherein the at least one reticle handler arm comprises:a static structure that is coupled to the reticle handler;an end part that is coupled to the static structure;a spring-damper system connecting the gripper to the static structure, anda locking mechanism having a first position, wherein the end part is substantially fixated with respect to the static structure, and a second position, wherein the end part is able to move within a predetermined range with respect to the static structure;using the reticle handler apparatus to pick up a reticle at a first location and drop off the respective reticle a second location, thereby:unlocking the locking mechanism in the first position when at least one end part of at least one reticle handler arm is provided with a reticle; andlocking the locking mechanism in the second position when none of the at least one reticle handler arm is provided with a reticle.

13. The method of claim 12, wherein the locking mechanism comprises one or more of:a moveable pen and corresponding opening;a moveable wedge and corresponding opposite wedge;one or more rotatable arms having an end provided with a brake for engaging or disengaging the end part;an electro magnet adapted to fixate the end part in the first position using attractive force; and an electro magnet adapted to fixate the end part in the first position using repulsive force.

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