Reticle storage system

Abstract

A reticle storage system comprises: at least one store configured to store at least part of a reticle pod; and a robot configured to transfer the at least part of the reticle pod into or out from the at least one store, wherein the at least one store is actuatable between a store position and a transfer position at which the robot is configured to transfer the at least part of the reticle pod into or out from the at least one store.

Description

RETICLE STORAGE SYSTEMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority of US application 63 / 729,679 which was filed on 09 December 2024 and which is incorporated herein in its entirety by reference.FIELD

[0002] The present disclosure relates generally to a reticle storage system, a reticle handler and a method of reticle storage. More particularly embodiments relate to photolithography systems that make use of multiple reticles.BACKGROUND

[0003] A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In that instance, a patterning device, which is alternatively referred to as a mask or a reticle, may be used to generate a circuit pattern to be formed on an individual layer of the IC. This pattern can be transferred onto a target portion (e.g., including part of, one, or several dies) on a substrate (e.g., a silicon wafer). Transfer of the pattern is typically via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate. In general, a single substrate will contain a network of adjacent target portions that are successively patterned. Modern high resolution tools are generally scanners, in which each target portion is irradiated by scanning the pattern through a radiation beam in a given direction (the “scanning”-direction) while synchronously scanning the substrate parallel or anti parallel to this direction.

[0004] Lithography tools have been developed to allow smaller and smaller devices to be patterned on a wafer. Lithographic tools and methods are being developed that utilize multiple exposure. During multiple exposure, two or more reticles are imaged sequentially based on reticle swapping between imaging. Multiple exposure is particularly advantageous in extreme ultra violet (EUV) imaging to overcome undesirably low kl imaging effects.

[0005] A solution to this problem has been implemented in which two or more reticles are stored in vacuum, allowing for faster swap between reticles. It is desirable to all for even faster swap between reticles.SUMMARY

[0006] In an aspect, a reticle storage system comprises: at least one store configured to store at least part of a reticle pod; and a robot configured to transfer the at least part of the reticle pod into or out from the at least one store, wherein the at least one store is actuatable between a store position and a transfer position at which the robot is configured to transfer the at least part of the reticle pod into or out fromthe at least one store.

[0007] In an aspect, a reticle storage method comprises: storing at least part of a reticle pod in at least one store; actuating the at least one store between a store position and a transfer position; and transferring the at least part of the reticle pod into or out from the at least one store with a robot when the at least one store is at the transfer position.

[0008] In an aspect, there is provided a non-transitory computer program product comprising machine- readable instructions configured to cause a processor to cause performance of a method described herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Embodiments will now be described, by way of example only, with reference to the accompanying drawings in which:

[0010] Figure 1 schematically illustrates a lithographic cell for use in manufacturing substrates in integrated circuit manufacturing;

[0011] Figure 2 schematically illustrates a reticle handling subsystem of the lithographic cell of Figure 1;

[0012] Figure 3 schematically illustrates an in-vacuum portion of a reticle handling subsystem;

[0013] Figure 4 is an isometric exploded view of a reticle pod in accordance with an embodiment;

[0014] Figure 5 schematically illustrates a portion of an in-vacuum reticle library in accordance with an embodiment;

[0015] Figure 6 schematically illustrates a reticle storage system;

[0016] Figure 7 is a diagram of a placement sequence of a robot of the reticle storage system;

[0017] Figure 8 is a diagram of a pickup sequence of the robot of the reticle storage system;

[0018] Figure 9 is a diagram of a comparative placement sequence;

[0019] Figure 10 is a diagram of a comparative pickup sequence;

[0020] Figure 11 schematically illustrates the reticle storage system shown in Figure 6;

[0021] Figure 12 schematically depicts an actuator of the reticle storage system of Figure 6; and

[0022] Figure 13 is a diagram of an alternative placement sequence or pickup sequence of the reticle storage system.DETAILED DESCRIPTION

[0023] Before describing embodiments in detail, it is instructive to present an example environment in which embodiments may be implemented.

[0024] As shown in Figure 1 , a lithographic apparatus LA may form part of a lithographic cell LC, also sometimes referred to as a lithocell or lithocluster, which also includes apparatus to perform one or more pre- and post-exposure processes on a substrate. Conventionally these include one or more spin coaters SC to deposit a resist layer, one or more developers DE to develop exposed resist, one or more chill plates CH and one or more bake plates BK. A substrate handler, or robot, RO picks up a substratefrom input / output ports I / Ol, I / O2, moves it between the different process devices and delivers it to the loading bay LB of the lithographic apparatus. These devices, which are often collectively referred to as the track, are under the control of a track control unit TCU which is itself controlled by the supervisory control system SCS, which also controls the lithographic apparatus via lithographic control unit LACU. Thus, the different apparatus may be operated to maximize throughput and processing efficiency.

[0025] Generally, a lithography tool LA can include an exposure chamber, a projection optical system that projects EUV and / or DUV light through a reticle mounted on a reticle stage onto a wafer to print images of a layer of, e.g., an integrated circuit. The lithography tool LA further may include a reticle handling system that exchanges the reticle being exposed as prescribed by the user of the lithography tool LA.

[0026] Reticle handling for use in EUV and / or DUV apparatus requires at least some steps wherein the reticles are handled in vacuum. For this purpose, within the lithographic apparatus, a reticle handling subsystem 200 as shown in Figure 2 may be included. The reticle handling subsystem may include a pod transport system 202, which may be an integrated pod transport and manual load station combined. The pod transport system interfaces with an atmospheric module 204. The atmospheric module 204 includes one or more load locks 206 which allow it to load reticles into the vacuum module 208. The load lock acts as a pressure-controlled input section to allow movement from atmospheric pressure in the atmospheric module 204 into vacuum in the vacuum module 208.

[0027] Within the vacuum module 208, may be an inspection station 210, which may include functionality to identify the input reticles, inspect the reticle, measure aspects such as the reticle's thickness, cleaning the reticle, and / or aligning the reticle relative to the lithography tool. Holding reticles in vacuum can be used to condition them prior to use, such that they do not introduce contaminants in the form of outgassed material that has, for example, adsorbed while the reticles are held in atmosphere. In addition, there is a reticle library 212 for storing at least one extra reticle, such that the reticle is quickly available for exchange. Also, based on information gathered at the inspection station, a processing station, and / or a location of the reticle in the reticle library, the stored reticle can be indexed to aid in retrieving the reticles during exposure.

[0028] Within the vacuum module 208 there is further a robot 220 (which may be, for example, an in vacuum robot) for moving reticles into and out of stores 222 (which may be referred to as reticle pod positions) of the reticle library 212. The reticle library stores one or more reticles for use in exposures, for example for use in multiple exposure imaging techniques, or for exposing different layers or patterns onto the wafer for different manufacturing steps.

[0029] The robot 220 exchanges reticles via a reticle exchange device 240 that is adapted to transfer reticles to the reticle stage of the lithography apparatus LA. The reticle exchange device may include one or more arms for holding reticles during loading, unloading, and exchanges.

[0030] Figure 3 illustrates in greater detail a portion of a vacuum module 208. The robot 220 is located centrally and movable among various stations within the vacuum module 208. In particular, it isconfigured to allow for moving reticles into and out of the stores 222 of the reticle library, or to and from the inspection station 210 and to and from the load locks (not seen in this figure). The in vacuum robot includes an arm 230 having an end effector 232 (which may also be referred to as a gripper, or holder). While the robot 220 is shown as having a single end effector 232, it may in principle have multiple end effectors, allowing it to grip more than one item at a time, for example.

[0031] The end effector is configured to hold a EUV inner pod (EIP, as seen best in Figure 4) 250 which typically includes a baseplate 252, a reticle 254, and a cover 256. In other embodiments, the end effector may be configured to hold an inner pod used in any lithographic apparatus. The cover 256 may include tabs or wings 258 that allow the cover to be lifted from the EIP 250. The baseplate 252 may include one or more containment pins 260 for guiding the reticle 254 into its proper position when it is subject to lateral displacement. Likewise, the cover 256 may include projections 262 that engage with the baseplate 252 to bear the weight of the cover 256, and to keep the cover 256 from touching the reticle 254.

[0032] Figure 5 is a partial view of the vacuum module 208, and in particular illustrating the reticle library 212. Three stores 222a-222c of the reticle library are shown, and the end effector 232 of the robot 220 is shown in one of the reticle pod positions. Adjacent to each of the three stores 222 is a respective pair of positions corresponding to each pod position. Specifically, locations Al and A2 are adjacent to store 222a, Bl and B2 are adjacent to store 222b, and Cl and C2 are adjacent to store 222c. As shown in the figure, the locations are substantially horizontally adjacent to each store 222a-c, but in principle they may be horizontally or vertically adjacent as desired. The amount of room available between pod positions, for example, may be small, requiring a vertical displacement rather than, or in addition to, a horizontal displacement. Irrespective of the direction of the displacement, the movement may be considered to be to a position adjacent to the pod position.

[0033] In an embodiment, the cover store itself may include actuators. In this approach, could include, for example, z-actuators such that the in vacuum robot may be stationary in the z-direction, while the actuators of the cover store moves the movable wing and takes the cover from the robot. This may allow, for example, reduced vibration of the robot in the z direction.

[0034] Figure 6 schematically depicts a reticle storage system 10. The reticle storage system 10 may have features of the vacuum module 208 described with reference to Figure 3, for example. In an embodiment the reticle storage system 10 is part of a vacuum module 208. For example, the reticle storage system may comprise a vacuum chamber such that the reticle storage system 10 is a vacuum module 208.

[0035] As shown in Figure 6, in an embodiment the reticle storage system 10 comprises at least one store 222. The store 222 may be referred to as a storage location, for example, a reticle storage location, a reticle storage position, a pod storage location, a pod storage position or a cover store. The store 222 may be for storing the reticle 254. Alternatively, the store may be a cover store for storing the cover 256 of the EIP 250. As shown in Figure 6, in an embodiment the reticle storage system 10 comprisesa plurality of stores 222. The arrangement shown in Figure 6 shows three stores 222. However, the number of stores 222 is not particularly limited. For example, the reticle storage system 10 may comprise at least five, optionally at least ten and optionally at least 20 stores 222.

[0036] In an embodiment the at least one store 222 is configured to store at least part of a reticle pod such as an EIP 250. For example, the at least one store 222 may be configured to store the EIP 250 or part of the EIP 250. For example, the at least one store 222 may be configured to store the cover 256 of the EIP 250. The at least one store 222 may be configured to store the baseplate 252 and / or reticle 254 of the EIP 250.

[0037] As shown in Figure 6, in an embodiment the reticle storage system 10 comprises a robot 220. The robot 220 is configured to transfer the at least part of the reticle pod 250 into or out from the at least one store 222. When the reticle storage system 10 comprises a vacuum chamber, the robot 220 may be a vacuum robot such as an in vacuum robot. As shown in Figure 3, in an embodiment the robot 220 comprises a mover which may comprise an arm 230. The arm 230 may be articulated. For example, the arm 230 may come in two or three pieces configured to hinge relative to each other. The arm 230 may be configured to rotate about a rotation axis R. For example, Figure 6 shows the robot 220 in plan view, with the rotation axis R shown.

[0038] The robot 220 may comprise an end effector 232. The end effector 232 may be formed integrally with the arm 230 or part of the arm 230. Alternatively, the end effector 232 may be hinged or otherwise articulated relative to the arm 230 of the robot 220. The end effector 232 is configured to engage with the at least part of the reticle pod 250.

[0039] In an embodiment the robot 220 is configured to transfer the at least part of the reticle pod 250 between the at least one store 222 and the reticle exchange device 240. When a reticle is to be exchanged, the robot 220 may be configured to transfer a used reticle from the reticle exchange device 240 to a store 222. The robot 220 may be configured to transfer a new (or previously used) reticle from a store 222 to the reticle exchange device 240.

[0040] As shown in Figure 6, in an embodiment the at least one store 222 is actuatable. The store may include at least one actuator. Figure 6 schematically shows three stores 222. In an embodiment, each store 222 is actuatable between a store position and a transfer position. At the transfer position the robot 220 is configured to transfer the at least part of the reticle pod 250 into or out from the at least one store 222.

[0041] For example, the diagram of Figure 6 shows the left-hand store 222 in the transfer position. In the transfer position, the robot 220 is configured to engage with the at least part of the reticle pod 250. In Figure 6, the central store 222 and the right-hand store 222 are shown in their respective store positions.

[0042] As shown in Figure 6, in an embodiment the arm 230 of the robot 220 may be in its retracted position. That is, the end effector 232 of the robot 220 is as close as it can get to the rotation axis R. The robot 220, and in particular the end effector 232, can reach the reticle 254 or cover 256, for example,without requiring the arm 230 to be extended radially outwards. This is because the left-hand store 222 is actuated to its transfer position.

[0043] The store 222 comprises a moveable shelf. The store 222 is moveable towards and away from the robot 220. Each store 222 may be radially moveable. Here, the term “radially” refers to the radial direction relative to the rotation axis R. In Figure 6, the rotation axis R is shown extending into an out from the paper. The radial direction extends outwardly from the rotation axis R within the plane of the paper.

[0044] In an embodiment the reticle storage system 10 comprises a controller. The controller is configured to control the robot 220. The controller is configured to control actuation of the at least one store 222. For example, the controller may be configured to actuate the store 222 towards the transfer position. This may help to reduce (or avoid) the robot 220 needing to move into (and from) the invacuum library, for example, where the EIPs 250 are stored. The controller may be configured to actuate the store 222 away from the transfer position, for example to the store position, such that the robot 220 does not need to move radially outwards into the in-vacuum library, for example.

[0045] By providing that the at least one store 222 is actuatable, the actuation required by the robot 220 may be reduced. Actuation of the robot 220 requires time. By reducing the actuation required by the robot 220, the time required for moving a reticle 254, or a cover 256 may be reduced. An embodiment of the invention is expected to increase throughput. An embodiment of the invention is expected to reduce the amount of time required for exchanging a reticle.

[0046] The process of exchanging a reticle can cause delays to exposure of substrates. In particular, when exposure of one or more substrates using a particular reticle takes a short amount of time, then the time required to position the subsequent reticle to be used ready for reticle exchange may cause a delay. By reducing the actuation required by the robot 220, the delay may be reduced or eliminated. An embodiment of the invention is expected to reduce or eliminate the impact of loading a reticle ready for reticle exchange on subsequent exposure processes.

[0047] As shown in Figure 6, in an embodiment the transfer position is closer that the store position to a main body of the robot 220. The main body of the robot 220 may comprise the arm 230 of the robot 220. The transfer position may be closer than the store position to the rotation axis R of the robot 220. When the store is actuated towards the transfer position, the store 222 is moved closer to the rotation axis R. When the store 222 is actuated to the store position, the store 222 becomes further from the rotation axis R.

[0048] Figure 7 schematically depicts a placement sequence performed by the reticle storage system 10. In Figure 7, arrows represent movements associated with the robot 220. Circles represent positions of the robot 220 relative to the store 222.

[0049] As shown in Figure 7, in an embodiment the controller is configured to control the robot 220 to move 21 to an upper entry position. For example, the robot 220 may rotate about the rotation axis R, for example from the reticle exchange device 240 so that the end effector 232 faces towards the store222. As shown in Figure 7, the controller may control the robot 220 to move 22 from the upper entry position 31 to the exchange position 33. At the exchange position 33, the end effector 232 may disengage from the reticle 254 or cover 256 so that the reticle 254 or cover 256 is placed in the store 222. Before the robot 220 is moved 22 to the exchange position 33, the store 222 is actuated to the transfer position. At the transfer position, the robot 220 at the exchange position 33 can place the reticle 254 or cover 256 in the store 222.

[0050] As shown in Figure 7, in an embodiment the controller is configured to control the robot 220 to move 23 from the exchange position 33 to the lower entry position 35. During a placement sequence, the end effector 232 of the robot 220 no longer holds the reticle 254 or cover 256 when the robot 220 is at the lower exchange position 35. As shown in Figure 7, in an embodiment the controller is configured to control the robot 220 to move 24 from the lower entry position 35. For example, the robot 220 may rotate about the rotation axis R, for example, so as to be ready to transfer another cover 256 or another reticle 254.

[0051] As shown in Figure 7, in an embodiment the robot 220 performs a substantially vertical movement in order to place the reticle 254 or cover 256 into the store 222. The robot 220 is not required to perform a radial movement, i.e. a movement away from or towards the rotation axis R.

[0052] Figure 8 is a diagram showing a pickup sequence performed by the robot 220. As shown in Figure 8, in an embodiment the controller is configured to control the robot 220 to move 26 to the lower entry position 35. The robot 220 may not be supporting any reticle 254 or cover 256 at this time. The controller is configured to control the robot 220 to move 27 from the lower entry position 35 to the exchange position 33. At the exchange position 33, the end effector 232 of the robot 220 may engage with the reticle 254 or cover 256. The movement 27 may be substantially vertical, for example upwards.

[0053] As shown in Figure 8, in an embodiment the controller is configured to control the robot 220 to move 28 from the exchange position 33 to the upper entry position 31. The movement 28 may be substantially vertical, for example upwards. During this movement 28, the end effector 232 may be carrying the reticle 254 or cover 256. As shown in Figure 8, in an embodiment the controller is configured to control the robot 220 to move 29 from the upper entry position 31. For example, the robot 220 may be configured to rotate about the rotation axis R so as to transfer the reticle 254 to the reticle exchange device 240.

[0054] Figure 9 schematically depicts a comparative placement sequence. As shown in Figure 9, the robot 220 may move 31 to the upper entry position 31 (for example by a rotational movement). The robot 220 may then be required to move 42 radially to an upper exchange position 32. The radial movement may be to move the end effector 232 radially away from the rotation axis R. In this comparative example, the store 222 may not be actuatable. This is why the robot 220 is required to perform the radial movement 42 to the upper exchange position 32. From the upper exchange position 32, the robot 220 moves 43 downwards through the exchange position 33 and further moves 44 downwards to the lower exchange position 34. At the lower exchange position 34, the robot moves 45radially to the lower entry position 35 and subsequently moves 46, for example rotationally.

[0055] As can be seen from a comparison between Figure 7 and Figure 9, the placement sequence shown in Figure 6 requires less movement compared to the comparative placement sequence shown in Figure 9. In an embodiment the placement sequence shown in Figure 7 requires less time compared to the comparative placement sequence shown in Figure 9.

[0056] Figure 10 is a diagram of a comparative pickup sequence. As shown in Figure 10, the robot 220 may move 51 to the lower entry position 35, subsequently move 52 radially to the lower exchange position 34 and then move 53 upwards to the exchange position 33. At the exchange position 33, the robot 220 may pickup the reticle 254 or cover 256. From the exchange position 33, the robot may move 54 upwards to the upper exchange position 32, move 55 radially inwards to the upper entry position 31 and move 56 rotationally so as to transfer the picked-up item.

[0057] As can be seen from a comparison between Figure 8 and Figure 10, the pickup sequence shown in Figure 8 requires fewer movements and therefore less time. This is because in the pickup sequence of Figure 8, the store 222 is actuatable, whereas in the pickup sequence shown in Figure 10 the store 222 is not actuated.

[0058] Figure 11 schematically depicts the reticle storage system 10 of Figure 6. In Figure 11, the robot 220 and stores 222 are shown in a different position. In Figure 11 , the robot 220 is shown with its arm 230 in a retracted position (compared to the position shown in Figure 3). The end effector 232 is pointing towards the right. The left-hand store 222 is in its store position. The central store 222 is in its transfer position. The right-hand store 222 is in its store position. In an embodiment the controller is configured to control the reticle storage system 10 such that one of the stores 222 is actuated into its transfer position while the other stores are in their storage position.

[0059] As shown in Figure 11, in an embodiment the store 222 is configured to be actuated to its transfer position before the robot 220 is in position to pickup or place the reticle 254 or cover 256, for example. In an embodiment the controller is configured to control actuation of the at least one store 222 to the transfer position before the robot 220 is at a rotational position at which the robot 220 is configured to transfer the at least part of the reticle pod 250 into or out from the at least one store. The store 222 may be moved towards or away from the robot 220 outside of the timing-critical path. The movement of the store 222 may not add or create any delay in exposure of substrates.

[0060] For example, in an embodiment the controller is configured to control the store 222 to move to the transfer position in preparation of placement of a reticle 254 or EIP 250 into the store 222. In an embodiment the controller is configured to actuate the store 222 towards the store position after transfer of an EIP 250 or reticle 254 or cover 256 towards the robot 220. In an embodiment the controller is configured to actuate a store 222 comprising the EIP 250 (or reticle 254 or cover 256) to the transfer position, in preparation for pickup by the 220 from the store 222. In an embodiment the controller is configured to actuate a store 222 comprising the EIP 250 (or reticle 254 or cover 256) to the store position, after transfer of the EIP 250 (or reticle 254 or cover 256) from the robot 220 to the store 222.

[0061] In an embodiment the controller is configured to control actuation of the at least one store 222 from the transfer position to the store position while the robot 220 is away from the rotational position at which the robot 220 is configured to transfer the at least part of the reticle pod 250 into or out from the at least one store 222. Movements of the store 222 may be performed at timings that do not contribute to the overall length of time required for exchange of a reticle, for example.

[0062] As shown in Figure 6, in an embodiment the reticle storage system 10 comprises a plurality of stores 222. Each store 222 may be configured to store at least part of a respective plurality of reticle pods 250. The robot 220 may be configured to selectively transfer the at least parts of the reticle pod 250 into or out from the plurality of stores 222. For example, the controller may control the actuation of the stores 222 and the robot 220 dependent on which of a plurality of reticle pods 250 is being transferred. The reticle storage system 10 may be used when it is required to exchange reticles so that different reticles can be used for exposing different lots of substrates. For example, the different reticles may correspond to different patterns to be exposed on the substrates.

[0063] Figure 12 is a schematic diagram of an actuatable store 222 of the reticle storage system 10. As shown in Figure 12, in an embodiment the reticle storage system 10 comprises at least one leadscrew actuator. The leadscrew actuator is configured to actuate the at least one store 222 between the store position and the transfer position. For example, Figure 12 schematically shows the actuator 11 and a leadscrew 14. The leadscrew may be referred to as a spindle. As shown in Figure 12, in an embodiment the actuatable store 222 comprises a mount 12. The mount 12 may be fixed to the leadscrew 14. For example, the mount 12 may be secured to an end of the leadscrew 14. Figure 12 shows the actuatable store 222 in its extended, i.e. transfer position. The actuator 11 is configured to actuate the leadscrew 14 so as to retract the leadscrew 14 (i.e. corresponding to an upwards movement in the orientation shown in Figure 12). The actuation of the leadscrew 14 causes the mount 12 to move together with the leadscrew 14. In an embodiment the store 222 is secured to the mount 12. The actuator 11 is configured to actuate the store 222 between the transfer position and the store position via the leadscrew 14.

[0064] As shown in Figure 12, in an embodiment the actuatable store 222 comprises a single leadscrew 14. In an alternative arrangement, as shown in Figure 6, for example, a plurality of spindles (e.g. leadscrews 14), may be provided. By providing a plurality (e.g. two) leadscrews 14, the store 222 and EIP 250 may be better supported by the mount 12. Undesirable sagging may be reduced. However, it is not essential for a plurality of lead screws 14 to be provided. A single leadscrew 14 may suffice, as shown in Figure 12.

[0065] It is not essential for a leadscrew actuator to be provided. In an alternative arrangement, the reticle storage system 10 may comprise at least one pneumatic actuator. The pneumatic actuator may be configured to actuate the at least one store 222 between the store position and the transfer position. For example, as shown in Figure 6, in an embodiment, the actuatable store 222 may comprise a plurality (e.g. two) rails 13. The rails 13 may be configured to guide the mount 12 with the store 222 secured to it between the transfer position and the store position. The actuator 11 is configured to actuate the store222 via the rails 13. It is not essential for a plurality of guiding rails 13 to be provided. In an alternative arrangement, a single guiding rail 13 may be provided for each actuatable store 222.

[0066] As shown in Figure 6, for example, in an embodiment the robot 220 comprises an end effector 232. The end effector 232 is configured to engage with the at least parts of the reticle pod 250. The robot 220 further comprises a mover. The mover is configured to move the end effector 232. For example, the mover may comprise the arm 230. The arm 230 may be articulated. The arm 230 may be pivoted about the rotational axis R.

[0067] As mentioned above, the store 222 may include Z-actuators such that the robot 220 may be stationary in the Z-direction. In an embodiment the at least one store 222 is actuatable parallel to the rotation axis R so as to transfer the at least part of the reticle pod into or out from the at least one store 222.

[0068] In the diagrams shown in Figure 7 and Figure 8, for example, the robot 220 is not required to make any radial movements. However, the robot 220 makes movements in the Z-direction (i.e. vertical movements) between the upper entry position 31, the exchange position 33 and the lower entry position 35. Figure 13 is a diagram of an alternative placement sequence or pickup sequence that may be performed by the reticle storage system 10. As shown in Figure 13, in an embodiment the controller is configured to control the robot 220 to move 61 to the exchange position 33. The movement may be, for example, a rotation about the rotation axis R. At the exchange position, the robot 220 may pickup an EIP 250, or a reticle 254 or a cover 256, for example. Alternatively, the robot 220 may place the EIP 250 or reticle 254 or cover 256 at the exchange position 33. At the exchange position 33, the store 222 may move in the Z-direction such that the robot 220 picks or places the item. The controller is configured to control the robot 220 to move 62 away from the exchange position 33. The movement may be, for example, a rotational movement.

[0069] As shown in Figure 13, it is not necessary for the robot 220 to move either in the radial direction or in the Z-direction. This may reduce the time required for a placement or pickup operation to be performed.

[0070] In an embodiment, the robot 220 comprises an isolator configured to isolate the end effector 232 from vibrations of the mover. By providing the isolator, the position of the end effector 232 may be controlled more accurately. The end effector 232 may be less affected by vibration of the mover, for example the arm 230 of the robot 220.

[0071] By isolating the end effector 232, the speed of motion of the end effector 232 may be limited. By providing the store 222 with actuators for radial and optionally also Z-direction movements, the time required for the robot 220 to move the end effector 232 for a pick or place operation may be reduced. This may be particularly advantageous when the robot comprises the isolator. An embodiment of the invention is expected to speed up pick or place operations, without unduly reducing accuracy of movement. An embodiment of the invention is expected to increase accuracy of movement, without unduly increasing the time required for a pick or place operation.

[0072] In an embodiment the reticle storage system 10 comprises a position sensor. The position sensor is configured to determine when the at least one store 222 is at the transfer position. Additionally, or alternatively, a position sensor may be provided to determine when the at least one store 222 is at the store position. The position sensor may be a proximity sensor located so as to determine the presence of the store 222. The position sensor may be positioned at, for example, the transfer position so as to determine when the store 222 is present. This may help to calibrate the actuation of the store 222.

[0073] In an embodiment the position of the store 222 is measured and provided as feedback for control of the actuation of the store 222. In an embodiment the actuatable store 222 comprises end stops configured to prevent the store 222 from moving beyond the range of movement between the store position and the transfer position. For example, an end stop may be provided to prevent the store 222 from moving radially inwards beyond the transfer position. Another end stop may be provided to prevent the store 222 from moving radially outwards beyond the store position. Further end stops may be provided for actuation in the Z-direction.

[0074] In an embodiment the reticle storage system 10 is part of a reticle handler module.

[0075] In an embodiment that may be combined with any of the foregoing embodiments, facility for storing two covers adjacent some or each of the stores 222 within the library may be provided. This can simplify the process of returning one pod to the library in an exchange operation where a cover is already stored in that position from a different pod.

[0076] As may be appreciated, certain of the above-described approaches may be better suited to one or more particular locations within the in vacuum library. For example, the embodiments using a lateral pocket with a movable wing, swing out arm, or swing bridge may best fit at locations Al and C2 of an in vacuum library as shown in view of the possibility of using lateral space adjacent the outermost of the reticle pod positions. The use of z-lift approaches may best fit at locations A2, Bl, B2, Cl, in between reticle pod positions, where lateral space may be at a premium. The precise combination of approaches taken will depend on the specifics of the space available within the in vacuum library volume, and differences in designs of the reticle pod positions may make additional room for side pockets more or less available than as in the configuration shown.

[0077] The terms “optimize”, “optimizing” and “optimization” as used herein mean adjusting a lithographic process parameter such that results and / or processes of lithography have a more desirable characteristic, such as higher accuracy of projection of a design layout on a substrate, a larger process window, etc.

[0078] An embodiment of the invention may take the form of a computer program containing one or more sequences of machine-readable instructions describing a method as disclosed herein, or a data storage medium (e.g. semiconductor memory, magnetic or optical disk) having such a computer program stored therein. Further, the machine readable instruction may be embodied in two or more computer programs. The two or more computer programs may be stored on one or more different memories and / or data storage media.

[0079] This computer program may be included, for example, with or within the inspection apparatus and / or with or within the control unit LACU of Figure 1. Where an existing apparatus, for example of the type shown in Figures 2 and 3, is already in production and / or in use, an embodiment can be implemented by the provision of updated computer program products for causing a processor of the apparatus to perform a method as described herein.

[0080] Any controllers described herein may each or in combination be operable when the one or more computer programs are read by one or more computer processors located within at least one component of the inspection apparatus. The controllers may each or in combination have any suitable configuration for receiving, processing, and sending signals. One or more processors are configured to communicate with the at least one of the controllers. For example, each controller may include one or more processors for executing the computer programs that include machine-readable instructions for the methods described above. The controllers may include data storage medium for storing such computer programs, and / or hardware to receive such medium. So the controller(s) may operate according the machine readable instructions of one or more computer programs.

[0081] 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 storage system, comprising: at least one store configured to store at least part of a reticle pod; and a robot configured to transfer the at least part of the reticle pod into or out from the at least one store, wherein the at least one store is actuatable between a store position and a transfer position at which the robot is configured to transfer the at least part of the reticle pod into or out from the at least one store.2. The reticle storage system of clause 1, wherein the transfer position is closer than the store position to a main body of the robot.3. The reticle storage system of clause 1 or 2, wherein the robot is configured to rotate about a rotation axis, wherein the transfer position is between the rotation axis and the store position.4. The reticle storage system of clause 3, wherein the at least one store is actuatable parallel to the rotation axis so as to transfer the at least part of the reticle pod into or out from the at least one store.5. The reticle storage system of any preceding clause, comprising: at least one leadscrew actuator configured to actuate the at least one store between the store position and the transfer position.6. The reticle storage system of any preceding clause, comprising: at least one pneumatic actuator configured to actuate the at least one store between the store position and the transfer position.7. The reticle storage system of any preceding clause, comprising: a controller configured to control the robot and actuation of the at least one store.8. The reticle storage system of clause 7, wherein the controller is configured to control actuation of the at least one store to the transfer position before the robot is at a rotational position at which the robot is configured to transfer the at least part of the reticle pod into or out from the at least one store.9. The reticle storage system of clause 7 or 8, wherein the controller is configured to control actuation of the at least one store from the transfer position to the store position while the robot is away from a rotational position at which the robot is configured to transfer the at least part of the reticle pod into or out from the at least one store.10. The reticle storage system of any preceding clause, comprising a plurality of stores each configured to store at least part of a respective plurality of reticle pods, wherein the robot is configured to selectively transfer the at least part of the reticle pod into or out from the plurality of stores.11. The reticle storage system of any preceding clause, wherein the at least one store comprises: at least one cover store configured to store a cover of the reticle pod.12. The reticle storage system of any preceding clause, wherein the at least one store comprises: at least one reticle pod position of a reticle library configured to store the reticle pod.13. The reticle storage system of any preceding clause, wherein the robot comprises: an end effector configured to engage with the at least part of the reticle pod; and a mover configured to move the end effector.14. The reticle storage system of clause 13, wherein the robot comprises: an isolator configured to isolate the end effector from vibration of the mover.15. The reticle storage system of any preceding clause, comprising: a vacuum chamber in which the at least one store is disposed, such that the reticle storage system is a vacuum module and the robot is a vacuum robot.16. The reticle storage system of any preceding clause, comprising: a position sensor configured to determine when the at least one store is at the transfer position.17. A reticle handler module comprising the reticle storage system of any preceding clause.18. A reticle storage method, comprising: storing at least part of a reticle pod in at least one store; actuating the at least one store between a store position and a transfer position; and transferring the at least part of the reticle pod into or out from the at least one store with a robot when the at least one store is at the transfer position.19. The reticle storage method of clause 18, wherein the at least one store is actuated to the transfer position before the robot is at a rotational position at which the robot is configured to transfer the at least part of the reticle pod into or out from the at least one store.20. The reticle storage method of clause 18 or 19, wherein the at least one store is actuated from the transfer position to the store position while the robot is away from a rotational position at which therobot is configured to transfer the at least part of the reticle pod into or out from the at least one store.

[0082] Although specific reference may have been made above to the use of embodiments in the context of lithography using radiation, it will be appreciated that an embodiment of the invention may be used in other applications, for example imprint lithography, and where the context allows, is not limited to lithography using radiation. In imprint lithography, a topography in a patterning device defines the pattern created on a substrate. The topography of the patterning device may 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.

[0083] Further, 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, liquid-crystal 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 (a tool that typically applies a layer of resist to a substrate and develops the exposed resist), a metrology tool and / or an inspection tool. 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.

[0084] The patterning device described herein may be referred to as a lithographic patterning device. Thus, the term “lithographic patterning device” may be interpreted as meaning a patterning device which is suitable for use in a lithographic apparatus.

[0085] The terms “radiation” and “beam” used herein encompass all types of electromagnetic radiation, including ultraviolet (UV) radiation (e.g. having a wavelength of or about 365, 355, 248, 193, 157 or 126 nm) and extreme ultra-violet (EUV) radiation (e.g. having a wavelength in the range of 5- 20 nm), as well as particle beams, such as ion beams or electron beams.

[0086] The term “lens”, where the context allows, may refer to any one or combination of various types of optical components, including refractive, reflective, magnetic, electromagnetic and electrostatic optical components.

[0087] The embodiment(s) described, and references in the specification to an “embodiment”, “example,” etc., indicate that the embodiment(s) described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular 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, itis 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.

[0088] The descriptions above are intended to be illustrative, not limiting. Thus, it will be apparent to one skilled in the art that modifications may be made to the invention as described without departing from the scope of the claims set out below. For example, one or more aspects of one or more embodiments may be combined with or substituted for one or more aspects of one or more other embodiments as appropriate. 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. It is to be understood that the phraseology or terminology herein is for the purpose of description by example, and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance. The breadth and scope of the invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims

CLAIMS1. A reticle storage system, comprising: at least one store configured to store at least part of a reticle pod; and a robot configured to transfer the at least part of the reticle pod into or out from the at least one store, wherein the at least one store is actuatable between a store position and a transfer position at which the robot is configured to transfer the at least part of the reticle pod into or out from the at least one store.

2. The reticle storage system of claim 1, wherein: the transfer position is closer than the store position to a main body of the robot; the robot is configured to rotate about a rotation axis, wherein the transfer position is between the rotation axis and the store position; and the at least one store is actuatable parallel to the rotation axis so as to transfer the at least part of the reticle pod into or out from the at least one store.

3. The reticle storage system of claim 1, comprising: at least one leadscrew actuator configured to actuate the at least one store between the store position and the transfer position.

4. The reticle storage system of claim 1 , comprising: at least one pneumatic actuator configured to actuate the at least one store between the store position and the transfer position.

5. The reticle storage system of claim 1, comprising a controller configured to control the robot and actuation of the at least one store, wherein: the controller is configured to control actuation of the at least one store to the transfer position before the robot is at a rotational position at which the robot is configured to transfer the at least part of the reticle pod into or out from the at least one store; and the controller is configured to control actuation of the at least one store from the transfer position to the store position while the robot is away from a rotational position at which the robot is configured to transfer the at least part of the reticle pod into or out from the at least one store.

6. The reticle storage system of claim 1 , comprising a plurality of stores each configured to store at least part of a respective plurality of reticle pods, wherein the robot is configured to selectively transfer the at least part of the reticle pod into or out from the plurality of stores.

7. The reticle storage system of claim 1, wherein the at least one store comprises: at least one cover store configured to store a cover of the reticle pod.

8. The reticle storage system of claim 1, wherein the at least one store comprises: at least one reticle pod position of a reticle library configured to store the reticle pod.

9. The reticle storage system of claim 1, wherein the robot comprises: an end effector configured to engage with the at least part of the reticle pod; and a mover configured to move the end effector.

10. The reticle storage system of claim 9, wherein the robot comprises: an isolator configured to isolate the end effector from vibration of the mover.

11. The reticle storage system of claim 1 , comprising: a vacuum chamber in which the at least one store is disposed, such that the reticle storage system is a vacuum module and the robot is a vacuum robot.

12. The reticle storage system of claim 1, comprising: a position sensor configured to determine when the at least one store is at the transfer position.

13. A reticle handler module comprising the reticle storage system of claim 1.

14. A reticle storage method, comprising: storing at least part of a reticle pod in at least one store; actuating the at least one store between a store position and a transfer position; and transferring the at least part of the reticle pod into or out from the at least one store with a robot when the at least one store is at the transfer position.

15. The reticle storage method of claim 14, wherein: the at least one store is actuated to the transfer position before the robot is at a rotational position at which the robot is configured to transfer the at least part of the reticle pod into or out from the at least one store; and the at least one store is actuated from the transfer position to the store position while the robot is away from a rotational position at which the robot is configured to transfer the at least part of the reticle pod into or out from the at least one store.

Images