Handler and method for moving patterning device

Abstract

A handler is configured to move a patterning device. The handler comprises a retractable rail. The handler further comprises an actuator configured to actuate the patterning device upwards along the retractable rail. The actuator is further configured to actuate the patterning device from a manual loading height to a load port height along the retractable rail. The retractable rail is upwardly retractable.

Description

HANDLER AND METHOD FOR MOVING PATTERNING DEVICECROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority of US application 63 / 721,323 which was filed on 15 November 2024 and which is incorporated herein in its entirety by reference.TECHNICAL FIELD

[0002] The description herein relates generally to a handler for moving a patterning device and a method for moving a patterning device, particularly for a lithographic apparatus.BACKGROUND

[0003] A lithography (e.g., projection) apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such a case, a patterning device (e.g., a reticle or mask) may contain or provide a pattern corresponding to an individual layer of the IC (“design layout”), and this pattern can be transferred onto a target portion (e.g. comprising one or more dies) on a substrate (e.g., silicon wafer) that has been coated with a layer of radiation-sensitive material (“resist”), by methods such as irradiating the target portion through the pattern on the patterning device. In general, a single substrate contains a plurality of adjacent target portions to which the pattern is transferred successively by the lithographic projection apparatus, one target portion at a time. In one type of lithographic projection apparatus, the pattern on the entire patterning device is transferred onto one target portion in one operation. Such an apparatus is commonly referred to as a stepper. In an alternative apparatus, commonly referred to as a step-and-scan apparatus, a projection beam scans over the patterning device in a given reference direction (the “scanning” direction) while synchronously moving the substrate parallel or anti-parallel to this reference direction. Different portions of the pattern on the patterning device are transferred to one target portion progressively. One or more patterning devices are provided to the lithography apparatus as needed to form the IC.

[0004] The lithography apparatus may have a loading station for loading a patterning device (e.g., reticle). It is desirable to increase the height to which the reticle can be loaded. It is desirable to reduce the footprint of the lithographic apparatus.SUMMARY

[0005] According to an embodiment, there is provided a handler for moving a patterning device, the handler comprising a retractable rail and an actuator configured to actuate the patterning device upwards along the retractable rail from a manual loading height to a load port height. The the retractable rail is upwardly retractable.

[0006] According to an embodiment, there is provided a method for moving a patterning device, the method comprising downwardly retracting a retractable rail and actuating the patterning device upwardsalong the retractable rail from a manual loading height to a load port height.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate one or more embodiments and, together with the description, explain these embodiments. Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts.

[0008] Fig. 1 schematically depicts a lithography apparatus, according to an embodiment.

[0009] Fig. 2 schematically depicts an embodiment of a lithographic cell or cluster, according to an embodiment.

[0010] Fig. 3 illustrates a portion of an extreme ultra violet (EUV) lithography apparatus, according to an embodiment.

[0011] Fig. 4 illustrates another example lithography apparatus (e.g., similar to an or the same as the lithography apparatus shown in Fig. 1 , with components similar to and / or the same as the components of the lithography apparatus shown in Fig. 3), according to an embodiment.

[0012] Fig. 5 illustrates a lithographay system, according to an embodiment.

[0013] Fig. 6 illustrates another view of the lithography system shown in Fig. 5, including a lithography apparatus, a loading station, a handling system, and / or other components, according to an embodiment.

[0014] Fig. 7 illustrates another view of a portion of a possible embodiment of the lithography system shown in Fig. 6 and Fig. 5, according to an embodiment.

[0015] Fig. 8 schematically depicts a handler for moving a patterning device, according to an embodiment.

[0016] Fig. 9 schematically depicts the handler of Fig. 8 with the patterning device raised, according to an embodiment.

[0017] Fig. 10 schematically depicts the handler of Fig. 8 with the patterning device at an intermediate position, according to an embodiment.

[0018] Fig. 11 schematically depicts the handler of Fig. 8 with the retractable rail retracted, according to an embodiment.

[0019] Fig. 12 schematically depicts an alternative view of the handler of Fig. 8, according to an embodiment.

[0020] Fig. 13, Fig. 14 and Fig. 15 schematically depict detection of failure of a belt of the pulley system shown in Fig. 12, according to an embodiment.

[0021] Fig. 16 schematically depicts an alternative failure detector, according to an embodiment.DETAILED DESCRIPTION

[0022] In general, a mask or reticle may be a transparent block of material that is covered with a pattern defined by a different, opaque material. Or a mask or reticle may be an opaque block of material coated with a patterned mirror, for example. Various masks are loaded into a lithography apparatus and used to form layers of a semiconductor device. The pattern defined on a given mask or reticle corresponds to features produced in one or more layers of the semiconductor device. Often, a plurality of masks or reticles are automatically loaded into a lithography apparatus during manufacturing and used to form corresponding layers of a semiconductor device.

[0023] Different lithography apparatuses often use drastically different hardware to load and / or handle reticles. Hardware differences are driven by different lithography apparatus configurations, which typically correspond to different numerical apertures (NA) associated with the lithography apparatuses, even though these lithography apparatuses have the same general design and processing requirements. Unfortunately, reticle handling hardware is often considered only after the patterning related portions of a lithography apparatus have been designed, and is only allowed to utilize leftover available space. This leftover available space differs between lithography apparatuses (e.g., between lithography apparatuses associated with different NA’s), which forces different design solutions.

[0024] Ideal reticle handling hardware would be common from lithography apparatus to lithography apparatus, and / or be flexible to accommodate lithography apparatuses with different configurations (e.g., for different NA’s).

[0025] Advantageously, the lithography systems (and corresponding methods) described herein facilitate commonality and flexibility in reticle handling hardware. The lithography systems (and corresponding methods) described herein provide a new design which meets reticle handling requirements, but in a condensed machine volume space compared to prior hardware. By reducing the required hardware volume, it is feasible to reserve a common volume across lithography apparatuses having different configurations (e.g., associated with different NA’s). As described herein, the present systems (and corresponding methods) comprise a lithography apparatus and a modular moveable loading station. The loading station is configured to move relative to the lithography apparatus, and be coupled with the lithography apparatus at a location corresponding to a patterning device (e.g., reticle) load port. The loading station is modular and configured to be moveably coupled with the lithography apparatus outside a footprint of a perimeter of the lithography apparatus at the location corresponding to the load port to accommodate different configurations of the lithography apparatus, and to facilitate maintenance of a common separation distance between the load port and a patterning device holder (e.g., a reticle stage) across the different configurations. The moveable modularity of the loading station facilitates a reduced footprint and / or volume of the lithography apparatus compared to one or more footprints of prior lithography apparatuses.

[0026] Although specific reference may be made in this text to the manufacture of integrated circuits (ICs), it should be understood that the description herein has many other possible applications. For example, it may be employed in the manufacture of integrated optical systems, guidance and detectionpatterns for magnetic domain memories, liquid-crystal display 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 interchangeable with the more general terms “mask”, “substrate” and “target portion”, respectively. In addition, any use of the terms “reticle” or “mask” herein may be considered synonymous with the more general term “patterning device.”

[0027] As an introduction, prior to transferring a pattern from a patterning device such as a mask to a substrate, the substrate may undergo various procedures, such as priming, resist coating and a soft bake. After exposure, the substrate may be subjected to other procedures (“post-exposure procedures”), such as a post-exposure bake (PEB), development, a hard bake and measurement and / or other inspection of the transferred pattern. This array of procedures is used as a basis to make an individual layer of a device, e.g., an IC. The substrate may then undergo various processes such as etching, ion-implantation (doping), metallization, oxidation, chemical mechanical polishing, etc., all intended to finish an individual layer of the device. If several layers are required in the device, then the whole procedure, or a variant thereof, is repeated for each layer. Eventually, a device will be present in each target portion on the substrate. These devices are then separated from one another by a technique such as dicing or sawing, whence the individual devices can be mounted on a carrier, connected to pins, etc.

[0028] Manufacturing semiconductor devices typically involves processing a substrate (e.g., a semiconductor wafer) using a number of fabrication processes to form various features and multiple layers of the devices. Such layers and features are typically manufactured and processed using, e.g., deposition, lithography, etch, chemical mechanical polishing, ion implantation, and / or other processes. Multiple devices may be fabricated on a plurality of dies on a substrate and then separated into individual devices. This device manufacturing process may be considered a patterning process. A patterning process involves a patterning step, such as optical and / or nanoimprint lithography using a patterning device in a lithography apparatus, to transfer a pattern on the patterning device to a substrate and typically, but optionally, involves one or more related pattern processing steps, such as resist development by a development apparatus, baking of the substrate using a bake tool, etching using the pattern using an etch apparatus, etc. One or more metrology processes are typically involved in the patterning process.

[0029] Lithography is a step in the manufacturing of devices such as ICs, where patterns formed on substrates define functional elements of the devices, such as microprocessors, memory chips, etc. Similar lithographic techniques are also used in the formation of flat panel displays, micro-electro mechanical systems (MEMS) and other devices.

[0030] Fig. 1 schematically depicts a lithography apparatus, according to an embodiment. Fig. 1 schematically depicts an embodiment of a lithography apparatus LA that may be included in and / or associated with the present systems and / or methods. The apparatus comprises: an illumination system (illuminator) IL configured to condition a radiation beam B (e.g., extreme ultraviolet (EUV) radiation);a holder comprising a support structure (e.g., a mask table) MT configured to support a patterning device (e.g. a mask) MA connected to a first positioner PM configured to accurately position the patterning device in accordance with certain parameters; a substrate table (e.g. a wafer table) WT (e.g., WTa, WTb or both) configured to hold a substrate (e.g. a resist-coated wafer) W and coupled to a second positioner PW configured to accurately position the substrate in accordance with certain parameters; and a projection system (e.g. a refractive projection lens system) PS configured to project a pattern imparted to the radiation beam B by patterning device MA onto a target portion C (e.g. comprising one or more dies and often referred to as fields) of the substrate W. The projection system is supported on a reference frame (RF). As depicted, the apparatus is of a transmissive type (e.g. employing a transmissive mask). Alternatively, the apparatus may be of a reflective type (e.g. employing a programmable mirror array of a type as referred to above, or employing a reflective mask).

[0031] The illuminator IL receives a beam of radiation from a radiation source SO. The source and the lithography apparatus may be separate entities, for example when the source is an excimer laser. In such cases, the source is not considered to form part of the lithography apparatus and the radiation beam is passed from the source SO to the illuminator IL with the aid of a beam delivery system BD comprising for example suitable directing mirrors and / or a beam expander. In other cases, the source may be an integral part of the apparatus, for example when the source is a mercury lamp. The source SO and the illuminator IL, together with the beam delivery system BD if required, may be referred to as a radiation system.

[0032] The illuminator IL may alter the intensity distribution of the beam. The illuminator may be arranged to limit the radial extent of the radiation beam such that the intensity distribution is non-zero within an annular region in a pupil plane of the illuminator IL. Additionally or alternatively, the illuminator IL may be operable to limit the distribution of the beam in the pupil plane such that the intensity distribution is non-zero in a plurality of equally spaced sectors in the pupil plane. The intensity distribution of the radiation beam in a pupil plane of the illuminator IL may be referred to as an illumination mode.

[0033] The illuminator IL may comprise adjuster AD configured to adjust the (angular / spatial) intensity distribution of the beam. Generally, at least the outer and / or inner radial extent (commonly referred to as o-outer and o-inner, respectively) of the intensity distribution in a pupil plane of the illuminator can be adjusted. The illuminator IL may be operable to vary the angular distribution of the beam. For example, the illuminator may be operable to alter the number, and angular extent, of sectors in the pupil plane wherein the intensity distribution is non-zero. By adjusting the intensity distribution of the beam in the pupil plane of the illuminator, different illumination modes may be achieved. For example, by limiting the radial and angular extent of the intensity distribution in the pupil plane of the illuminator IL, the intensity distribution may have a multi-pole distribution such as, for example, a dipole, quadrupole or hexapole distribution. A desired illumination mode may be obtained, e.g., by inserting an optic which provides that illumination mode into the illuminator IL or using a spatial lightmodulator.

[0034] The illuminator IL may be operable to alter the polarization of the beam and may be operable to adjust the polarization using adjuster AD. The polarization state of the radiation beam across a pupil plane of the illuminator IL may be referred to as a polarization mode. The use of different polarization modes may allow greater contrast to be achieved in the image formed on the substrate W. The radiation beam may be unpolarized. Alternatively, the illuminator may be arranged to linearly polarize the radiation beam. The polarization direction of the radiation beam may vary across a pupil plane of the illuminator IL. The polarization direction of radiation may be different in different regions in the pupil plane of the illuminator IL. The polarization state of the radiation may be chosen in dependence on the illumination mode. For multi-pole illumination modes, the polarization of each pole of the radiation beam may be generally perpendicular to the position vector of that pole in the pupil plane of the illuminator IL. For example, for a dipole illumination mode, the radiation may be linearly polarized in a direction that is substantially perpendicular to a line that bisects the two opposing sectors of the dipole. The radiation beam may be polarized in one of two different orthogonal directions, which may be referred to as X-polarized and Y-polarized states. For a quadrupole illumination mode, the radiation in the sector of each pole may be linearly polarized in a direction that is substantially perpendicular to a line that bisects that sector. This polarization mode may be referred to as XY polarization. Similarly, for a hexapole illumination mode the radiation in the sector of each pole may be linearly polarized in a direction that is substantially perpendicular to a line that bisects that sector. This polarization mode may be referred to as TE polarization.

[0035] In addition, the illuminator IL generally comprises various other components, such as an integrator IN and a condenser CO. The illumination system may include various types of optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof, for directing, shaping, or controlling radiation. Thus, the illuminator provides a conditioned beam of radiation B, having a desired uniformity and intensity distribution in its cross section.

[0036] The holder or support structure MT supports the patterning device in a manner that depends on the orientation of the patterning device, the design of the lithography apparatus, and other conditions, such as for example whether or not the patterning device is held in a vacuum environment. The support structure may use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterning device. The support structure may be a frame or a table, for example, which may be fixed or movable as required. The support structure may ensure that the patterning device is at a desired position, for example with respect to the projection system.

[0037] The term “patterning device” used herein should be broadly interpreted as referring to any device that can be used to impart a pattern in a target portion of the substrate. A patterning device may be any device that can be used to impart a radiation beam with a pattern in its cross-section to create a pattern in a target portion of the substrate. It should be noted that the pattern imparted to the radiationbeam may not exactly correspond to the desired pattern in the target portion of the substrate, for example if the pattern includes phase-shifting features or so called assist features. Generally, the pattern imparted to the radiation beam will correspond to a particular functional layer in a device being created in a target portion of the device, such as an integrated circuit. A patterning device may be transmissive or reflective. Examples of patterning devices include reticles or masks.

[0038] The projection system PS may comprise a plurality of optical (e.g., lens) elements and may further comprise an adjustment mechanism configured to adjust one or more of the optical elements to correct for aberrations (phase variations across the pupil plane throughout the field). To achieve this, the adjustment mechanism may be operable to manipulate one or more optical (e.g., lens) elements within the projection system PS in one or more different ways. The projection system may have a coordinate system wherein its optical axis extends in the z direction. The adjustment mechanism may be operable to do any combination of the following: displace one or more optical elements; tilt one or more optical elements; and / or deform one or more optical elements. Displacement of an optical element may be in any direction (x, y, z, or a combination thereof). Tilting of an optical element is typically out of a plane perpendicular to the optical axis, by rotating about an axis in the x and / or y directions although a rotation about the z axis may be used for a non-rotationally symmetric aspherical optical element. Deformation of an optical element may include a low frequency shape (e.g. astigmatic) and / or a high frequency shape (e.g. free form aspheres). Deformation of an optical element may be performed for example by using one or more actuators to exert force on one or more sides of the optical element and / or by using one or more heating elements to heat one or more selected regions of the optical element. In general, it may not be possible to adjust the projection system PS to correct for apodization (transmission variation across the pupil plane). The transmission map of a projection system PS may be used when designing a patterning device (e.g., mask) MA for the lithography apparatus LA. Using a computational lithography technique, the patterning device MA may be designed to at least partially correct for apodization.

[0039] The lithography apparatus may be of a type having two (dual stage) or more tables (e.g., two or more substrate tables WTa, WTb, two or more patterning device tables, a substrate table WTa and a table WTb below the projection system without a substrate that is dedicated to, for example, facilitating measurement, and / or cleaning, etc.). In such “multiple stage” machines, the additional tables may be used in parallel, or preparatory steps may be carried out on one or more tables while one or more other tables are being used for exposure. For example, alignment measurements using an alignment sensor AS and / or level (height, tilt, etc.) measurements using a level sensor LS may be made.

[0040] In operation of the lithography apparatus, a radiation beam is conditioned and provided by the illumination system IL. The radiation beam B is incident on the patterning device (e.g., reticle or mask) MA, which is held on the support structure (e.g., mask table) MT. Having traversed the patterning device MA, the radiation beam B passes through the projection system PS, which focuses the beam onto a target portion C of the substrate W. With the aid of the second positioner PW andposition sensor IF (e.g., an interferometric device, linear encoder, 2-D encoder, or capacitive sensor), the substrate table WT can be moved accurately, e.g. to position different target portions C in the path of the radiation beam B. Similarly, the first positioner PM and another position sensor (which is not explicitly depicted in Fig. 1) can be used to accurately position the patterning device MA with respect to the path of the radiation beam B, e.g. after mechanical retrieval from a mask library, or during a scan. In general, movement of the support structure MT may be realized with the aid of a long-stroke module (coarse positioning) and a short-stroke module (fine positioning), which form part of the first positioner PM. Similarly, movement of the substrate table WT may be realized using a long-stroke module and a short-stroke module, which form part of the second positioner PW. In the case of a stepper (as opposed to a scanner), the support structure MT may be connected to a short-stroke actuator only, or may be fixed. Patterning device MA and substrate W may be aligned using patterning device alignment marks Ml, M2 and substrate alignment marks Pl, P2. Although the substrate alignment marks as illustrated occupy dedicated target portions, they may be located in spaces between target portions (these are known as scribe-lane alignment marks). Similarly, in situations in which more than one die is provided on the patterning device MA, the patterning device alignment marks may be located between the dies.

[0041] The depicted apparatus may be used in step mode or scan mode. In step mode, the support structure MT and the substrate table WT are kept essentially stationary, while a pattern imparted to the radiation beam is projected onto a target portion C at one time (i.e. a single static exposure). The substrate table WT is then shifted in the X and / or Y direction so that a different target portion C can be exposed. In step mode, the maximum size of the exposure field limits the size of the target portion C imaged in a single static exposure. In scan mode, the support structure MT and the substrate table WT are scanned synchronously while a pattern imparted to the radiation beam is projected onto a target portion C (i.e. a single dynamic exposure). The velocity and direction of the substrate table WT relative to the support structure MT may be determined by the (de-) magnification and image reversal characteristics of the projection system PS. In scan mode, the maximum size of the exposure field limits the width (in the non-scanning direction) of the target portion in a single dynamic exposure, whereas the length of the scanning motion determines the height (in the scanning direction) of the target portion. In another mode, the support structure MT is kept essentially stationary holding a programmable patterning device, and the substrate table WT is moved or scanned while a pattern imparted to the radiation beam is projected onto a target portion C. In this mode, generally a pulsed radiation source is employed, and the programmable patterning device is updated as required after each movement of the substrate table WT or in between successive radiation pulses during a scan. This mode of operation can be readily applied to maskless lithography that utilizes programmable patterning device, such as a programmable mirror array of a type as referred to above. Combinations and / or variations on the abovedescribed modes of use or entirely different modes of use may also be employed.

[0042] A substrate 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) or a metrology orinspection 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 includes multiple processed layers.

[0043] The terms “radiation” and “beam” encompass all types of electromagnetic radiation, including ultraviolet (UV) or deep ultraviolet (DUV) radiation (e.g. having a wavelength of 365, 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.

[0044] Various patterns on or provided by a patterning device may have different process windows, i.e., a space of processing variables under which a pattern will be produced within specification. Examples of pattern specifications that relate to potential systematic defects include checks for necking, line pull back, line thinning, critical dimension (CD), edge placement, overlapping, resist top loss, resist undercut and / or bridging. The process window of the patterns on a patterning device or an area thereof may be obtained by merging (e.g., overlapping) process windows of each individual pattern. The boundary of the process window of a group of patterns comprises boundaries of process windows of some of the individual patterns. In other words, these individual patterns limit the process window of the group of patterns. These patterns can be referred to as “hot spots” or “process window limiting patterns (PWLPs),” which are used interchangeably herein. When controlling a part of a patterning process, it is possible and economical to focus on the hot spots. When the hot spots are not defective, it is most likely that other patterns are not defective.

[0045] Fig. 2 schematically depicts an embodiment of a lithographic cell or cluster, according to an embodiment. As shown in Fig. 2, the lithography apparatus LA may form part of a lithographic cell LC, also sometimes referred to a lithocell or cluster, which also includes apparatuses to perform pre- and post-exposure processes on a substrate. Conventionally these include one or more spin coaters SC to deposit one or more resist layers, one or more developers to develop exposed resist, one or more chill plates CH and / or one or more bake plates BK. A substrate handler, or robot, RO picks up one or more substrates from input / output port I / Ol, I / O2, moves them between the different process apparatuses and delivers them to the loading bay LB of the lithography apparatus. These apparatuses, 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 lithography apparatus via lithography control unit LACU. Thus, the different apparatuses can be operated to maximize throughput and processing efficiency.

[0046] In order that a substrate that is exposed by the lithography apparatus is exposed correctly and consistently and / or in order to monitor a part of the patterning process (e.g., a device manufacturing process) that includes at least one pattern transfer step (e.g., an optical lithography step), it is desirable to inspect a substrate or other object to measure or determine one or more properties such as alignment, overlay (which can be, for example, between structures in overlying layers or between structures in asame layer that have been provided separately to the layer by, for example, a double patterning process), line thickness, critical dimension (CD), focus offset, a material property, etc. For example, contamination on reticle clamp membranes (e.g., as described herein) may adversely affect overlay because clamping a reticle over such contamination will distort the reticle. Accordingly, a manufacturing facility in which lithocell LC is located also typically includes a metrology system that measures some or all of the substrates W (Fig. 1) that have been processed in the lithocell or other objects in the lithocell. The metrology system may be part of the lithocell LC, for example it may be part of the lithography apparatus LA (such as alignment sensor AS (Fig. 1)).

[0047] The one or more measured parameters may include, for example, alignment, overlay between successive layers formed in or on the patterned substrate, critical dimension (CD) (e.g., critical linewidth) of, for example, features formed in or on the patterned substrate, focus or focus error of an optical lithography step, dose or dose error of an optical lithography step, optical aberrations of an optical lithography step, etc. This measurement may be performed on a target of the product substrate itself and / or on a dedicated metrology target provided on the substrate. The measurement can be performed after-development of a resist but before etching, after-etching, after deposition, and / or at other times.

[0048] There are various techniques for making measurements of the structures formed in the patterning process, including the use of a scanning electron microscope, an image -based measurement tool and / or various specialized tools. As discussed above, a fast and non-invasive form of specialized metrology tool is one in which a beam of radiation is directed onto a target on the surface of the substrate and properties of the scattered (diffracted / reflected) beam are measured. By evaluating one or more properties of the radiation scattered by the substrate, one or more properties of the substrate can be determined. This may be termed diffraction-based metrology. One such application of this diffractionbased metrology is in the measurement of feature asymmetry within a target. This can be used as a measure of overlay, for example, but other applications are also known. For example, asymmetry can be measured by comparing opposite parts of the diffraction spectrum (for example, comparing the -1st and +lstorders in the diffraction spectrum of a periodic grating). Another application of diffractionbased metrology is in the measurement of feature width (CD) within a target.

[0049] Metrology results may be provided directly or indirectly to the supervisory control system SCS. If an error is detected, an adjustment may be made to exposure of a subsequent substrate (especially if the inspection can be done soon and fast enough that one or more other substrates of the batch are still to be exposed) and / or to subsequent exposure of the exposed substrate. Also, an already exposed substrate may be stripped and reworked to improve yield, or discarded, thereby avoiding performing further processing on a substrate known to be faulty. In a case where only some target portions of a substrate are faulty, further exposures may be performed only on those target portions which meet specifications.

[0050] Within a metrology system, a metrology apparatus is used to determine one or moreproperties of the substrate, and in particular, how one or more properties of different substrates vary, or different layers of the same substrate vary from layer to layer. As noted above, the metrology apparatus may be integrated into the lithography apparatus LA or the lithocell LC or may be a stand-alone device.

[0051] To enable the metrology, one or more targets can be provided on the substrate. In some embodiments, the target is specially designed and may comprise a periodic structure. In some embodiments, the target is a part of a device pattern, e.g., a periodic structure of the device pattern. In some embodiments, the device pattern is a periodic structure of a memory device (e.g., a Bipolar Transistor (BPT), a Bit Line Contact (BLC), etc. structure).

[0052] In some embodiments, the target on a substrate may comprise one or more 1-D periodic structures (e.g., gratings), which are printed such that after development, the periodic structural features are formed of solid resist lines. In some embodiments, the target may comprise one or more 2-D periodic structures (e.g., gratings), which are printed such that after development, the one or more periodic structures are formed of solid resist pillars or vias in the resist. The bars, pillars, or vias may alternatively be etched into the substrate (e.g., into one or more layers on the substrate).

[0053] As lithography nodes keep shrinking, more and more complicated wafer designs may be implemented. Various tools and / or techniques may be used by designers to ensure complex designs are accurately transferred to physical wafers. These tools and techniques may include mask optimization, source mask optimization (SMO), OPC, design for control, and / or other tools and / or techniques. The present systems, and / or methods may be used as stand-alone tools and / or techniques, and / or or used in conjunction with semiconductor manufacturing processes, to enhance the accurate transfer of complex designs to physical wafers.

[0054] Fig. 3 illustrates a portion of an extreme ultra violet (EUV) lithography apparatus, according to an embodiment. Fig. 3 illustrates additional example portions of a lithography apparatus LA (e.g., similar to and / or the same as lithography apparatus LA shown in Fig. 1). Fig. 3 illustrates a portion of an extreme ultra violet (EUV) lithography apparatus. Fig. 3 illustrates example lithography apparatus components in proximity to a support structure MT (e.g. clamp) of lithography apparatus LA, including a tool handler, and / or other components.

[0055] In some embodiments, a tool handler comprises a reticle handler turret gripper, a reticle handler robot gripper (both having associated components for gripping a reticle during transport), and / or other components. The reticle handler robot gripper may, for example, move a reticle from a pod (e.g., after a user places a reticle in the pod and loads the pod into the lithography apparatus). The reticle handler turret gripper may, for example, move a reticle from the reticle handler robot gripper to the support structure MT. Lithography apparatus LA may include various other mechanical components (translation mechanisms, elevation mechanisms, rotational mechanisms, motors, power generation and transmission components, structural components, etc.) configured to facilitate movement and control of the patterning device MA through the lithography apparatus LA.

[0056] Fig. 4 illustrates another example lithography apparatus (e.g., similar to an or the same as thelithography apparatus shown in Fig. 1 , with components similar to and / or the same as the components of the lithography apparatus shown in Fig. 3), according to an embodiment. Fig. 4 illustrates another example lithography apparatus LA (e.g., similar to and / or the same as lithography apparatus LA shown in Fig. 1 , with components similar to and / or the same as the components of lithography apparatus LA shown in Fig. 1 and / or lithography apparatus LA shown in Fig. 3). A footprint 414 of the lithography apparatus LA is shown in Fig. 4, with a length L400 of lithography apparatus LA also shown. Lithography apparatus LA comprises a loading station 404, a reticle handling system 406, and / or other components. Various components of lithography apparatus LA may be similar to an or the same as corresponding components of lithography apparatus LA shown in Fig. 1 , and / or lithography apparatus LA shown in Fig. 3.

[0057] One or more standards (e.g., SEMI El 17, SEMI S2, etc.) may govern the design and / or location of one or more components of lithography apparatus LA. For example, loading station 404 is configured to receive reticles input into lithography apparatus LA. In the lithography apparatus LA, loading station 404 is a permanent part of the lithography apparatus LA, located at a location 410 at or near an end of lithography apparatus LA (corresponding to a patterning device (e.g., reticle) load port 412 (or load ports 412 - two example load ports 412 are shown in Fig. 4). Loading station 404 is inside a footprint 414 of a perimeter 416 of lithography apparatus LA at location 410 (e.g., according to the requirements of SEMI El 17).

[0058] In lithography apparatus LA, a reticle in an inner pod and an outer pod may be loaded into loading station 404. Reticle handling system 406 includes a first handler 550 configured to move a reticle from loading station 404 to a load port 412, an arm based robot 411 configured to move the reticle from the load port, and / or other portions configured to move the reticle to the support structure MT. Distance 420 from load port(s) 412 to support structure MT in lithography apparatus LA spans across arm based robot 411. Distance 420 often varies in lithography apparatuses of different configurations (e.g., associated with different NA’s). Reticle handling system 406 and loading station 404 are typically designed after configuration the design of lithography related portions 480 of lithography apparatus LA are complete, which means that designs for reticle handling system 406 and loading station 404 often vary apparatus to apparatus (while still complying with the various required standards).

[0059] Fig. 5 illustrates a lithography system 500, according to an embodiment. Lithography system 500 comprises a lithography apparatus LA, a moveable loading station 404, a handling system 506, and / or other components. Lithography apparatus LA may be an EUV apparatus, for example. Various components of lithography apparatus LA may be similar to an or the same as corresponding components of lithography apparatus LA shown in Fig. 1, lithography apparatus LA shown in Fig. 3, and / or lithography apparatus LA shown in Fig. 4. However, in system 500, loading station 404 is configured to move 508 relative to lithography apparatus LA, and be coupled with lithography apparatus LA at a location 410 corresponding to a patterning device (e.g., reticle) load port 412 (or load ports 412 - twoexample load ports 412 are shown in Fig. 5). Loading station 404 is modular and configured to be moveably coupled with lithography apparatus LA outside a footprint 514 of a perimeter 516 of lithography apparatus LA at location 410 corresponding to load port(s) 412 to accommodate different configurations of lithography apparatus LA, and to facilitate maintenance of a common separation distance 420 between load port(s) 412 and a support structure MT (e.g., a reticle stage) across the different configurations. The different configurations may correspond to different numerical apertures (NA) associated with the lithography apparatus, for example. These NA’s may include 0.33, 0.55, 0.75, and / or other NA’s, for example. (Note that the moveable modularity of loading station 404 may contradict one of more of the required lithography apparatus design standards mentioned above.)

[0060] The moveable modularity of loading station 404 facilitates a reduced footprint 514 and / or volume (e.g., coming out of the page in Fig. 5) of lithography apparatus LA compared to one or more footprints of prior lithography apparatuses (e.g., footprint 414 of apparatus LA shown in Fig. 4). For example, as shown in Fig. 5 compared to Fig. 4, the length L500 of a side of system 500 is less than a corresponding length L400 of lithography apparatus LA (e.g., L500 « L400). Length L500 may be less than length L400 by up to about 250mm, 500mm, 750mm, 1000mm, or more, for example.

[0061] As described herein, lithography apparatus LA is configured to transfer a pattern from a patterning device MA to a substrate (not shown in Fig. 5, but see example substrate W in Fig. 1). In some embodiments, lithography apparatus LA comprises an EUV scanner, patterning device MA comprises a reticle, and the substrate comprises a wafer, for example. Lithography apparatus LA is configured to receive the substrate, which has a photoresist layer (e.g., as described with respect to Fig.2 above). Lithography apparatus LA is configured to direct radiation from a radiation source (see Fig.1) toward the substrate via patterning device MA (once inserted into lithography apparatus LA) to transfer the pattern from patterning device MA onto the photoresist layer; and facilitate removal a portion of the photoresist layer to form the pattern over the substrate, to form one or more integrated circuits or chips in or on the substrate (e.g., see Fig. 1 and Fig. 2).

[0062] As described above, loading station 404 is configured to be removably coupled with lithography apparatus LA at location 410, corresponding to load port(s) 412. In some embodiments, loading station 404 may comprise a sheet metal type design like a tool box (e.g., square with wheels). Loading station 404 is configured to receive one or more patterning devices MA for movement to load port(s) 412. Movement 508 of loading station 404 may be performed manually by a user, automatically (e.g., controlled by one or more processors), and / or in other ways. In some embodiments, loading station 404 comprises wheels, one or more rails, a track, a retractable shelf, and / or other components configured to facilitate movement relative to lithography apparatus LA. Loading station 404 may have an input configured to receive reticles from a user and / or a manual insertion system, one or more storage locations such as slots, an output so that reticles can be moved out of loading station 404 by handling system 506 (as described herein), and / or other components. In some embodiments, loading station 404 may have a rectangular cross section, be made of relatively light weight materials to enhance portability,and / or any have any other characteristics that allow it to function as described.

[0063] In some embodiments, a patterning device MA is held within an inner pod 532 and an outer pod 534 in loading station 404. One or more of these patterning device / inner pod / outer pod combinations may be in loading station 404 at a given time. Loading station 404 is configured to accept an outer pod 534, which may include one or more features defining how the pod is held. For example, the bottom of a pod door may have a semi mechanical interface, with pins for registration of the pod. The perimeter of a pod may have lead-ins and / or other features, which help the operator place the pod into position. There may also be one or more sensors which sense pod presence and whether a pod is placed properly. Loading station 404 may comprise an electrical connection so that the sensors can be connected to machine logic. Fig. 5 provides an example inset view 580 of a user 582 loading an outer pod 534 into loading station 404. As shown in view 580, various features 590 (e.g., guiding surfaces, registration pins, pin holes, etc., on loading station 404, outer pod 534, or both) may be used to help user 582 properly load outer pod 534 into loading station 404.

[0064] In some embodiments, the removable coupling of loading station 404 is configured to have repeatable accuracy for connection to lithography apparatus LA (e.g., plus or minus about 5mm (as one possibility) relative to the mechanism which will pick up the pod (e.g., as described herein). The repeatably accurate removable coupling may comprise a docking station to main machine covers of lithography apparatus LA, for example, and / or other components.

[0065] In some embodiments, lithography system 500 comprises a handling system 506. Handling system 506 may comprise a first handler 550 configured to move a patterning device MA from loading station 404 to a load port 412, and a second handler 552 configured to move the patterning device MA from load port 412 to support structure MT. In some embodiments, second handler 552 may move a patterning device MA after head 562 moves patterning device MA from load port 412 to a load lock 598. First handler 550 is configured to move outer pod 534 to a load port 412, and second handler 552 is configured to move patterning device MA from inner pod 532 at load port 412 to support structure MT.

[0066] In some embodiments, first handler 550 comprises a cartesian robot. In some embodiments, first handler 550 comprises a pick and place robot. In some embodiments, first handler 550 comprises an overhead hoist transport. First handler 550 may comprise some combination of any of these, and / or other mechanisms. In some embodiments, first handler 550 comprises one or more rails 560 configured to facilitate movement of patterning device MA from loading station 404 to a load port 412 in one or more dimensions. For example, Fig. 5 illustrates first handler 550 as a cartesian or pick and place robot that moves 564 along first and second rails. In this example, the first and second rails comprise a linear rail oriented in an x or y dimension relative to the lithography apparatus (x in this example), and a z-rail oriented in a z dimension (in and out of the page in Fig. 5) relative to lithography apparatus LA, respectively. First handler 550 also comprises a head 562 configured to move 566 in the y direction in this example (toward and away from load ports 412), and rotate 568 (e.g., around the z axis) as needed.First handler 550 may include various motors, actuators, bearings, guides, tracks, controllers, processors, sensors, structural components, clips, clamps, and / or other grippers, and / or any other hardware and / or software components needed to facilitate the functionality described herein.

[0067] Hardware of handling system 506 can be substantially the same across different configurations of lithography apparatuses LA (e.g., corresponding to different NA’s) because the modular and moveably coupled loading station 404 facilitates maintenance of separation distance 420 between load port(s) 412 and support structure MT across different configurations of lithography apparatus LA. For example, in some embodiments, the modular and movably coupled loading station 404 is configured to reduce or eliminate a need for a selective compliance assembly robot arm (SCARA) such as arm based robot 411 shown in Fig. 4, or the reticle handler robot gripper described above with respect to Fig. 3, in first handler 550.

[0068] In this example, distance 420 between loading station 404 and the load port is reduced compared to a corresponding distance in prior lithography apparatuses. Comparing Fig. 5, to Fig. 4, distance 420 in lithography apparatus LA shown in Fig. 4, spans across arm based robot 411. Arm based robot 411 is not needed at all in lithography apparatus LA because loading station 404 can be moved (e.g., via wheels or some other mechanism) to any convenient location where a load port 412 is designed into lithography apparatus LA. In this example, loading station 404 is coupled at location 410, right at, or at least proximate to, load port(s) 412 (instead of at the far end of lithography apparatus LA where loading station 404 is a permanent part of lithography apparatus LA). Because loading station 404 can be moved, distance 420 from load port(s) 412 can be substantially the same for any configuration of lithography apparatus LA. In other words, load port(s) 412 and support structure MT (e.g., a reticle stage) can be moved together left or right - in this example image of a lithography apparatus LA, with distance 420 being kept the same wherever they are moved. Since loading station 404 is coupled at location 410, arm based robot 411 from lithography apparatus LA shown in Fig. 4, and / or the reticle handler robot gripper mentioned above with respect to Fig. 3, is not needed to move a reticle from a load port 412. Instead, a relatively simply (compared to arm based robot 411 in lithography apparatus LA and the reticle handler robot gripper in lithography apparatus LA) pick and place robot can be used.

[0069] Fig. 6 illustrates another view of the lithography system shown in Fig. 5, including a lithography apparatus, a loading station, a handling system, and / or other components, according to an embodiment. Fig. 6 illustrates another view of lithography system 500, including lithography apparatus LA, loading station 404, handling system 506 (including first handler 550), and / or other components. In Fig. 6, system 500 is shown in an x-z orientation (compared to the x-y orientation shown in Fig. 5). Loading station 404 is configured to move relative to lithography apparatus LA, and be coupled with lithography apparatus LA at a location 410 corresponding to a patterning device (e.g., reticle) load port 412 (or load ports 412 - two example load ports 412 are shown in Fig. 6). As shown in Fig. 6, in some embodiments, first handler 550 comprises one or more rails 560 configured to facilitate movement of apatterning device from loading station 404 to a load port 412 in one or more dimensions. For example, first handler 550 may comprise an overhead hoist transport 600 with a telescoping linear x rail 602. Rail 602 may telescope out, and over loading station 404, such that one or more components 606 (e.g., wires, cables, a platform, etc.) of an overhead hoist mechanism may retrieve (moving 604 in the z direction in this example) a reticle from loading station 404. In some embodiments, One or more sensors, actuators, controllers, etc., may be used to control any of these movements. Loading station 404 can be rolled 610 (in this example) away and stored in a designated location 612 for each lithography apparatus (NA) configuration. Only one such loading station 404 is needed for a plurality of lithography apparatuses LA (e.g., which may be in proximity to each other).

[0070] Fig. 7 illustrates another view of a portion of a possible embodiment of the lithography system shown in Fig. 6 and Fig. 5, according to an embodiment. As another example, Fig. 7 illustrates another view of a possible embodiment of a portion of lithography system 500, including lithography apparatus LA, loading station 404, handling system 506 (including first handler 550), and / or other components. In Fig. 7, system 500 is shown in a perspective view. As shown in Fig. 7, first handler 550 may comprise one or more rails 560 (e.g., a telescoping linear x rail 602) configured to facilitate movement of a patterning device MA (loaded by a user 582 in this example) from loading station 404 to a load port 412 in one or more dimensions. In this example, loading station 404 comprises a flip down shelf 710 which comes out of a machine enclosure 712. Shelf 710 may fold back into machine enclosure 712 when not in use, for example. In this embodiment, machine covers may be different for each machine platform to accommodate different locations of loading station 404. Since the machine covers are generally not critical to a main lithography machine, this is acceptable. Note that this configuration (the flip down shelf) may have components similar and / or the same as those described above for guiding the user to load an outer pod, registering correctly, sensing whether an outer pod had been loaded correctly, etc.

[0071] Fig. 8 schematically depicts a handler for moving a patterning device, according to an embodiment. Fig. 8 schematically depicts a handler 550, which may be, for example, the first handler 550 of a lithography apparatus LA or a lithography system 500. As shown in Fig. 8, in an embodiment the handler 550 comprises a retractable rail 81. The retractable rail 81 is a rail along which another component can slide. The retractable rail 81 is configured to guide movement of a patterning device MA. As shown in the orientation in Fig. 8, in an embodiment the retractable rail 81 is generally oriented vertically during use. That is, when the handler 550 is used for moving a patterning device MA, then the retractable rail 81 is generally vertically oriented. When the handler 550 is not being used for moving patterning devices MA, then the retractable rail 81 may be oriented differently. For example, when the handler 550 or a lithographic apparatus LA or lithographic system 500 comprising the handler 550 is to be transported, then the retractable rail 81 may be oriented horizontally, for example.

[0072] As shown in Fig. 8, in an embodiment the handler 550 comprises an actuator 83. The actuator 83 is configured to actuate the patterning device MA upwards along the retractable rail 81. In anembodiment the patterning device MA is movable between a manual loading height and a load port height. The actuator 83 may be configured to actuate the patterning device MA upwards along the retractable rail 81 from the manual loading height to the load port height.

[0073] Fig. 8 schematically depicts a patterning device MA at the manual loading height. The manual loading height is lower than the load port height. The manual loading height corresponds to the height at which a user can manually load a patterning device MA onto the handler 550. When the patterning device MA is loaded onto the handler 550, the patterning device MA may be held within an inner pod 532 and an outer pod 534. The load port height may correspond substantially to the height of one or more load ports 412, for example of a lithography apparatus LA or a lithography system 500. The handler 550 is configured to raise the patterning device MA from the height at which it is manually loaded to the height at which it can reach a load port 412 so as to be handled by one or more robots of the lithography apparatus LA or lithography system 500.

[0074] Fig. 9 schematically depicts the handler of Fig. 8 with the patterning device raised, according to an embodiment. Fig. 9 schematically depicts the handler 550 of Fig. 8, with the patterning device MA raised to the load port height. From a comparison between Fig. 8 and Fig. 9, it can be seen that the patterning device MA is raised from the manual loading height shown in Fig. 8 to the load port height shown in Fig. 9.

[0075] As shown in the comparison between Fig. 8 and Fig. 9, in an embodiment the retractable rail 81 is upwardly retractable. Fig. 9 schematically shows the retractable rail 81 in its retracted state. Fig.8 shows the retractable rail 81 in its extended state. Between the extended state shown in Fig. 8 and the retracted state shown in Fig. 9, the retractable rail 81 may be positioned in a range of intermediate states. For example, during the transition from the extended state to the retracted state, the retractable rail 81 may be in an intermediate state.

[0076] When the retractable rail 81 is in its retracted state as shown in Fig. 9, the handler 550 takes up a smaller volume compared to when the retractable rail 81 is in its extended state. The handler 550 may be kept with its retractable rail 81 in the retracted state when it is desirable to minimise the volume of the handler 550. For example, during packaging or transport of the handler 550, or a lithography apparatus LA or lithography system 500 comprising the handler 550, the retractable rail 81 may be retracted. An embodiment of the invention is expected to facilitate packaging and / or transport of the handler 550.

[0077] In an embodiment the retractable rail 81 is configured to guide movement of the patterning device MA along at least part of the path between the manual loading height and the load port height. By providing a rail, the mechanism for lifting the patterning device MA to the load port height may be less complex and / or easier to implement than a hoist system, for example. An embodiment of the invention is expected to make it easier to manufacture the handler 550 for moving the patterning device MA.

[0078] When the retractable rail 81 is in its retracted state, then the space vacated by the retractablerail 81 may be used for one or more other components. For example, a substrate handler may use the space that is unblocked when the retractable rail 81 is retracted. An embodiment of the invention is expected to facilitate use of other pieces of hardware of a lithography apparatus LA or lithography system 500.

[0079] As shown in Fig. 8, in an embodiment the handler 550 comprises a telescopic assembly. The telescopic assembly comprises the retractable rail 81. The telescopic assembly provides a relatively simple and reliable way of allowing the retractable rail 81 to be retracted. An embodiment of the invention is expected to improve reliability of the handler 550.

[0080] As shown in Fig. 8, in an embodiment the telescopic assembly comprises an upper rail 82. The telescopic assembly also comprises the retractable rail 81. As shown in Fig. 8, in an embodiment the upper rail 81 is generally vertically higher than the retractable rail 81 during use of the handler 550. In an embodiment the retractable rail 81 is slidable along the upper rail 82. For example, as shown in Fig. 8, in an embodiment the retractable rail 81 is mounted onto an upper rail carriage 89. The upper rail carriage 89 is configured to slide along the upper rail 82. In an embodiment a plurality of upper rail carriages 89 are provided. In an embodiment the upper rail carriage 89 is configured to engage with an end stop when the upper rail carriage 89 is at its lowest position, as shown in Fig. 8. The end stop may be provided on or fixed relative to the upper rail 82. The end stop may be configured to prevent the upper rail carriage 89 from sliding off the bottom end of the upper rail 82.

[0081] As shown in Fig. 8, in an embodiment the retractable rail 81 is mounted onto the upper rail carriage 89. The retractable rail 81 may be secured to, for example fixed to, the upper rail carriage 89.

[0082] As shown in Fig. 9, when the patterning device MA is raised to the load port height, then the upper rail carriage 89 is at its highest point relative to the upper rail 82. In an embodiment the upper rail carriage 89 is configured to engage with an end stop when the upper rail carriage 89 is at its highest location relative to the upper rail 82. The end stops may limit movement of the retractable rail 81 relative to the upper rail 82.

[0083] In an embodiment the upper rail 82 is fixed relative to a frame of the handler 550. In an embodiment the actuator 83 is fixed relative to the same frame of the handler 550.

[0084] As shown in Fig. 8, in an embodiment the upper rail 82 is substantially parallel to the retractable rail 81. The upper rail 82 may be generally vertically oriented during use of the handler 550. By providing that the upper rail 82 is substantially parallel to the retractable rail 81, the path length for moving the patterning device MA guided by the telescopic assembly may be substantially maximised. An embodiment of the invention is expected to increase the distance by which the patterning device MA may be moved for a given size of handler 550.

[0085] As shown in Fig. 8, in an embodiment the handler 550 comprises a patterning device support 80. The patterning device support 80 is configured to support the patterning device MA. For example, the patterning device support 80 may be configured to support a patterning device MA held within an inner pod 532 and an outer pod 534. The outer pod 534 may be manually loaded by a user onto thepatterning device support 80. In an embodiment the patterning device support 80 comprises a rim. The rim may be raised relative to the surface on which the patterning device MA is placed. The rim may help to reduce the possibility of the patterning device MA moving or sliding off the patterning device support 80 during movement of the patterning device MA.

[0086] As shown in Fig. 8, in an embodiment the handler 550 comprises a retractable rail carriage 88. In an embodiment a plurality of retractable rail carriages 88 are provided. The retractable rail carriage 88 may be configured to slide along the retractable rail 81. The retractable rail 81 is configured to guide movement of the retractable rail carriage 88.

[0087] As shown in Fig. 8, in an embodiment the patterning device support 80 is mounted onto the retractable rail carriage 88. The patterning device support 80 may be fixed relative to the retractable rail carriage 88.

[0088] During use of the handler 550, the patterning device MA may be lifted by lifting the patterning device support 80. The retractable rail 81 guides the patterning device support 80 as it moves from the manual loading height shown in Fig. 8.

[0089] Fig. 10 schematically depicts the handler of Fig. 8 with the patterning device at an intermediate position, according to an embodiment. Fig. 10 schematically depicts the handler 550 when the patterning device MA is moving from the manual loading height towards the load port height. In Fig. 10, the patterning device MA is about halfway along its path from the manual loading height shown in Fig. 8 to the load port height shown in Fig. 9.

[0090] As shown in Fig. 10, when the patterning device MA is actuated upwards, then the patterning device support 80 and the retractable rail carriage 88 slide upwards relative to the retractable rail 81. The retractable rail 81 may initially remain in its extended state. For example, Fig. 10 shows the patterning device MA at an intermediate position, but with the retractable rail 81 remaining in its extended state.

[0091] In an embodiment when the retractable rail carriage 88 is at its lowest position relative to the retractable rail 81, then the retractable rail carriage 88 engages with an end stop. As shown in Fig. 10, during lifting of the patterning device MA, the retractable rail carriage 88 is raised to its highest point relative to the retractable rail 81. In an embodiment when the retractable rail carriage 88 reaches its highest point relative to the retractable rail 81, the retractable rail carriage 88 engages with an end stop.

[0092] When the retractable rail carriage 88 engages with the end stop, then continued lifting of the patterning device MA causes the retractable rail 81 to be raised relative to the upper rail 82. The upper rail carriage 89 begins to slide along the upper rail 82. The patterning device MA is raised from its intermediate position shown in Fig. 10 to its load port height shown in Fig. 9. When the patterning device MA is at the load port height, the retractable rail 81 may be retracted.

[0093] In an embodiment, during a first phase of moving the patterning device MA, the retractable rail 81 may remain in its extended state. The patterning device MA may be raised relative to the retractable rail 81. During a second, subsequent phase of moving the patterning device MA, theretractable rail 81 may be retracted. During retraction of the retractable rail 81 , the patterning device MA continues to be raised from an intermediate position to the load port height.

[0094] In an embodiment the handler 550 comprises a rail lock. The rail lock is configured to controllably lock the retractable rail 81 in its retracted state. In an embodiment the handler 550 comprises a controller configured to control the rail lock so as to controllably lock the retractable rail 81 in its retracted state.

[0095] For example, when the patterning device support 80 is raised to its highest position as shown in Fig. 9, then the rail lock may be used so as to lock the retractable rail 81 in its retracted state. Once the retractable rail 81 is locked in its retracted state, then the patterning device support 80 may be lowered without the retractable rail 81 extending towards its extended state.

[0096] Fig. 11 schematically depicts the handler of Fig. 8 with the retractable rail retracted, according to an embodiment. Fig. 11 schematically depicts the handler 550 with the retractable rail 81 locked in its retracted state and the patterning device support 80 lowered to its lowest possible position relative to the retractable rail 81.

[0097] Typically, when the retractable rail 81 is not locked in its retracted state, then when the patterning device support 80 is lowered from its highest position shown in Fig. 9, then the retractable rail 81 extends towards its extended state as shown in Fig. 10. However, when the retractable rail 81 is locked by the rail lock, then lowering of the patterning device support 80 causes the patterning device support 80 to be lowered relative to the retractable rail 81 (instead of the retractable rail 81 lowering relative to the upper rail 82).

[0098] When the retractable rail 81 is locked in its retracted state, then the handler 550 takes up less space while still allowing up and down movement of the patterning device support 80. This allows the handler 550 to be used to move the patterning device MA vertically in more restricted volumes. For example, it may be desirable to test the up and down movement of the patterning device support 80 within a volume that could not accommodate the retractable rail 81 in its fully extended state. An embodiment of the invention is expected to make it easier to test functioning of the handler 550. However, it is not essential for the rail lock to be provided. The rail lock may be omitted.

[0099] As shown from the transition from Fig. 8 to Fig. 9 via Fig. 10, in an embodiment the actuator 83 is configured to actuate the patterning device support 80 upwards, so as to actuate the patterning device MA upwards along the retractable rail 81 from the manual loading height to the load port height. The actuator 83 is configured to apply a force on the patterning device support 80 so as to move the patterning device MA. The force may be applied directly to the patterning device support 80. The actuation for moving the patterning device MA may be implemented relatively simply. It is not necessary for the upper rail carriage 89 or the retractable rail carriage 88, for example, to be active components requiring independent actuation. An embodiment of the invention is expected to reduce the cost for manufacturing the handler 550.

[0100] As shown in Fig. 8, in an embodiment the patterning device support 80 comprises anengagement member 87. In an embodiment the actuator 83 is configured to apply a lifting force directly to the engagement member 87 of the patterning device support 80. The engagement member 87 may be a hook, or a peg, for example.

[0101] As shown in Fig. 9 and Fig. 10, for example, when the retractable rail 81 is retracted, the handler 550 is above the manual loading height. It may be impossible for a user to manually load a patterning device MA directly to the load port height. The patterning device MA may require a user to use two hands to lift and move the patterning device MA. It would be unsafe for the user to use a series of steps while carrying the patterning device MA so as to reach the load port height. The retractable rail 81 allows the user to place the patterning device MA onto the handler 550 at the manual loading height. The retractable rail 81 may then be retracted such that all of the handler 550 is above the manual loading height.

[0102] As shown in Fig. 8, in an embodiment the actuator 83 comprises a pulley system. The pulley system is configured to lift the patterning device MA. For example, as shown in Fig. 8 in an embodiment the pulley system comprises a first spooling pulley 84. The first spooling pulley 84 may be mounted onto a shaft 85. The shaft 85 may be rotatable. In an embodiment the actuator 83 is configured to rotate the shaft 85 so as to rotate the spooling pulley 84. In an embodiment the shaft 85 may be rotated in either direction so as to control lifting and lowering of the patterning device MA.

[0103] As shown in Fig. 8, in an embodiment a first belt 86 is spooled around the first spooling pulley 84. In an embodiment the first belt 86 is configured to be in tension during use of the handler 550. The first belt 86 may be engaged with the engagement member 87 of the patterning device support 80. For example, the first belt 86 may be hooked around the engagement member 87 of the patterning device support 80.

[0104] Fig. 12 schematically depicts an alternative view of the handler of Fig. 8, according to an embodiment. Fig. 12 schematically depicts the handler 550 shown in Fig. 8. Fig. 12 shows the handler 550 from a viewpoint from the righthand side of Fig. 8.

[0105] As shown in Fig. 12, in an embodiment the pulley system comprises a plurality of belts 76, 86. For example, as explained above the pulley system may comprise the first belt 86 spooled around the first spooling pulley 84. As shown in Fig. 12, in an embodiment the pulley system further comprises a second belt 76. The pulley system may comprise a second spooling pulley 74. The second belt 76 may be spooled around the second spooling pulley 74.

[0106] As shown in Fig. 12, in an embodiment the second belt 76 is engaged with a second engagement member 77 of the patterning device support 80. In an embodiment, each belt 76, 86 is configured to lift the patterning device MA upwards along the retractable rail 81. By providing a plurality of belts 76, 86, there may be some redundancy. By providing redundancy, the safety of the handler 550 may be improved. For example, if one of the belts 76, 86 were to fail, then the patterning device MA could be held by the remaining belt. It is particularly important to ensure that the handler 550 is safe during use because the patterning device MA is manually loaded onto the handler 550.During use of the handler 550, a user may be located generally below the handler 550. An embodiment of the invention is expected to improve the safety of a user manually loading patterning devices MA onto the handler 550.

[0107] As shown in Fig. 12, in an embodiment the pulley system comprises a plurality of spooling pulleys 74, 84. The spooling pulleys 74, 84 are for driving respective belts 76, 86 of the plurality of belts. In the arrangement shown in Fig. 12, the pulley system comprises two spooling pulleys 74, 84 and two belts 76, 86. In an alternative arrangement, more than two spooling pulleys and more than two belts may be provided. In a further alternative embodiment, the pulley system may comprise only a single spooling pulley and a single belt. For example, the second spooling pulley 74 and the second belt 76 may be omitted.

[0108] As shown in Fig. 12, in an embodiment the pulley system comprises a connecting belt 75. The connecting belt 75 may be referred to as a timing belt. The connecting belt is configured to connect the spooling pulleys 74, 84 such that the spooling pulleys are configured to spool at substantially the same rate. The connecting belt 75 may be configured to synchronise spooling by the spooling pulleys 74, 84. By synchronising the spooling pulleys 74, 84, the possibility of one of the belts 76, 86 becoming undesirably slack or preventing lowering, for example, of the patterning device support 80 may be reduced.

[0109] During use of the handler 550, it may be expected that the load of the patterning device support 80 with the patterning device MA is mostly supported by the first belt 86. The second belt 76 may be configured to bear a minor portion of the load.

[0110] In an embodiment the handler 550 comprises a failure detector. The failure detector is configured to detect a failure of the pulley system. For example, in an embodiment the failure detector is configured to detect a failure of at least one of the plurality of belts 76, 86.

[0111] During use of the handler 550, there is a possibility that a belt may deteriorate or break. When the belt breaks, then the belt can no longer bear the tension to support the patterning device support 80. By providing redundancy in the number of belts, the possibility of the patterning device support 80 falling in an uncontrolled manner may be reduced. It is desirable to determine that a belt has failed so that the handler 550 may be repaired and the possibility of unsafe use of the handler 550 may be reduced.

[0112] However, it is not essential for the failure detector to be provided. The failure detector may be omitted.

[0113] In an embodiment the failure detector is configured such that failure of a first belt 86 of the plurality of belts 76, 86 causes a detector element to move from a first position to a second position. This is explained with reference to Fig. 13 and Fig. 14.

[0114] As shown in Fig. 12, in an embodiment the pulley system comprises a first idler pulley 90 and a second idler pulley 70. The first idler pulley 90 is configured to support the first belt 86. The second idler pulley 70 is configured to support the second belt 76. The idler pulleys may be passive. The idler pulleys may rotate when the belts 76, 86 are spooled.

[0115] Fig. 13, Fig. 14 and Fig. 15 schematically depict detection of failure of a belt of the pulley system shown in Fig. 12, according to an embodiment.

[0116] Fig. 13 is a close-up schematic view of the second idler pulley 70. The second belt 76 is shown extending around the second idler pulley 70. The second belt 76 may apply a downwards force on the second idler pulley 70. As shown in Fig. 13, in an embodiment the handler 550 comprises an upward forcer 71. The upward forcer 71 is configured to apply an upward force on the second idler pulley 70. The upward forcer 71 is configured to apply a upward force on the second idler pulley 70 that balances the downward force applied by the presence of the second belt 76.

[0117] As shown in Fig. 13, in an embodiment the upward forcer 71 may be secured to a frame 73 of the handler 550. For example, as shown in Fig. 13 the upward forcer 71 may be a spring. Fig. 13 shows the second idler pulley 70 in a nominal position relative to the frame 73. The second idler pulley 70 may remain in this nominal position while the upward force applied by the upward forcer 71 is balanced with the downward force applied by the second belt 76. When the first belt 86 is functioning correctly, then the second idler pulley 70 may remain in its nominal position shown in Fig. 13.

[0118] Fig. 14 schematically depicts the second idler pulley 70 when the first belt 86 has failed. As shown in Fig. 14, the failure detector is configured such that failure of the first belt 86 causes the second idler pulley 70 to move from a first position (i.e. the nominal position shown in Fig. 13) to a second position (i.e. the primary belt failure position shown in Fig. 14). The second idler pulley 70 may be the detector element of the failure detector.

[0119] In an embodiment the failure detector comprises a sensor configured to detect whether the detector element is at the first position. The sensor may be a proximity sensor. The sensor may be configured to detect the presence of the detector element. For example, the sensor may be configured to detect when the second idler pulley 70 is moved from its nominal position. The sensor may be configured to output a failure signal to provide an alert that the first belt 86 has failed.

[0120] When the first belt 86 fails, then the tension in the second belt 76 increases because it is bearing all of the load of the patterning device support 80. The increased tension in the second belt 76 increases the downward force applied by the second belt 76 on the second idler pulley 70. The increased downward force causes the position of the second idler pulley 70 to be moved downwards. In the arrangement shown in Fig. 14, the spring is extended.

[0121] Fig. 15 schematically depicts another close-up view of the second idler pulley 70. Fig. 15 shows the position of the second idler pulley 70 when the second belt 76 fails. When the second belt 76 fails, then the tension in the second belt 76 decreases. The decrease in tension causes the downward force applied by the second belt 76 on the second idler pulley 70 to decrease. The decrease in downward force causes the second idler pulley 70 to move upwards. As shown in Fig. 15, the spring may contract.

[0122] As shown in Fig. 13, in an embodiment the upward forcer 71 is connected between the frame 73 of the handler 550 and a mounting point 72 of the second idler pulley 70. The mounting point 72 may be located centrally with respect to the second idler pulley 70. For example, the mounting point72 may be at the axis of rotation of the second idler pulley 70.

[0123] As shown in Fig. 15, in an embodiment the failure detector is configured such that failure of the second belt 76 causes the detector element (e.g. the second idler pulley 70) to move from the first position (i.e. the nominal position shown in Fig. 13) to a third position (i.e. the secondary belt failure position shown in Fig. 15).

[0124] In an embodiment the failure detector is configured to detect failure of the connecting belt 75. In an embodiment the actuator 83 is configured to rotate the shaft 85 which is connected to the first spooling pulley 84. The actuator 83 is configured to drive the first spooling pulley 84. In an embodiment the actuator 83 is configured such that it does not directly actuate the second spooling pulley 74. The second spooling pulley 74 may be driven via its connection to the first spooling pulley 84 via the connecting belt 75. The connecting belt 75 may cause the second spooling pulley 74 to rotate.

[0125] When the connecting belt 75 fails, then the second spooling pulley 74 is no longer driven. This may reduce the tension in the second belt 76, reducing the downward force applied by the second belt 76 on the second idler pulley 70. As a result, the failure of the connecting belt 75 may cause the second idler pulley 70 to raise to its position shown in Fig. 15. In an embodiment the failure detector is configured such that the detector element is moved to the same position whether the second belt 76 or the connecting belt 75 fails. An embodiment of the invention provides a failure detection mechanism of using one sensor to detect three different failure modes.

[0126] It is not essential for the failure detector to be arranged as shown in figs. 13-15.

[0127] Fig. 16 schematically depicts an alternative arrangement of the failure detector, according to an embodiment. Fig. 16 shows a close-up view of the second idler pulley 70 of the pulley system. The second belt 76 is spooled around the second idler pulley 70.

[0128] As shown in Fig. 16, in an embodiment the handler 550 comprises a detector element 79. The detector element 79 is part of the failure detector. As shown in Fig. 16, in an embodiment the detector element 79 is configured to be rotatable about a pivot 78. The pivot 78 may be fixed relative to a frame 73 of the handler 550.

[0129] As shown in Fig. 16, the second idler pulley 70 may be secured to the detector element 79 at one side of the pivot 78. In an embodiment a counterbalance forcer 71 is connected between the frame 73 and the detector element 79. For example, a spring may be connected between the frame 73 and the mounting point 72 of the detector element 79. The mounting point 72 may be on the other side of the pivot 73 from the second idler pulley 70.

[0130] During normal use of the handler 550 (i.e. when both the first belt 86 and the second belt 76 are functioning correctly), the force applied by the second idler pulley 70 on the detector element 79 may balance with the force applied by the counterbalance forcer 71 on the detector element 79. The detector element 79 may have its position as shown in Fig. 16.

[0131] When the first belt 86 fails, then the tension in the second belt 76 may increase. The increase in tension of the second belt 76 increases the force applied by the second idler pulley 70 on the detectorelement 79. As a result, the detector element 79 may rotate anti-clockwise (in the orientation shown in Fig. 16) about the pivot 78. When the detector element 79 rotates anti-clockwise, then the detector element 79 may no longer cover the sensor 91. The sensor 91 may be configured to detect the presence or absence of the detector element 79. When the sensor 91 detects that the detector element 79 is no longer present, then it may be determined that there has been a failure in one of the belts.

[0132] Alternatively, when the second belt 76 or the connecting belt 75 fails, then the tension in the second belt 76 may decrease. The decrease in tension in the second belt 76 may cause the force applied by the second idler pulley 70 on the detector element 79 to decrease. As a result of the decrease applied by the second idler pulley 70, the detector element 79 may rotate clockwise (in the orientation shown in Fig. 16). When the detector element 79 rotates clockwise, then the detector element 79 may no longer cover the sensor 91. The sensor 91 may be configured to detect the absence of the detector element 79, thereby signaling that a belt has failed.

[0133] 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 handler for moving a patterning device, the handler comprising:a retractable rail; andan actuator configured to actuate the patterning device upwards along the retractable rail from a manual loading height to a load port height;wherein the retractable rail is upwardly retractable.2. The handler of clause 1 , wherein the handler comprises a telescopic assembly comprising the retractable rail.3. The handler of clause 2, wherein the telescopic assembly comprises:an upper rail; andthe retractable rail slidable along the upper rail.4. The handler of clause 3, wherein the upper rail is substantially parallel to the retractable rail.5. The handler of any preceding clause, comprising:a rail lock configured to controllably lock the retractable rail in its retracted state.6. The handler of any preceding clause, comprising:a patterning device support configured to support the patterning device, wherein the patterning device support is slidable along the retractable rail.7. The handler of clause 6, wherein the actuator is configured to actuate the patterning device support upwards, so as to actuate the patterning device upwards along the retractable rail from the manual loading height to the load port height.8. The handler of any preceding clause, wherein the retractable rail is upwardly retractable such that when the retractable rail is retracted, the handler is above the manual loading height.9. The handler of any preceding clause, wherein the actuator comprises a pulley system configured to lift the patterning device.10. The handler of clause 9, wherein the pulley system comprises a plurality of belts, each belt configured to lift the patterning device upwards along the retractable rail, so as to provide redundancy.11. The handler of clause 10, comprising:a failure detector configured to detect a failure of the pulley system.12. The handler of clause 11, wherein the failure detector is configured to detect a failure of at least one of the plurality of belts.13. The handler of clause 11 or 12, wherein the failure detector is configured such that failure of a first belt of the plurality of belts causes a detector element to move from a first position to a second position.14. The handler of clause 13, wherein the failure detector is configured such that failure of a second belt of the plurality of belts causes the detector element to move from the first position to a third position.15. The handler of clause 14, wherein the pulley system comprises:a plurality of spooling pulleys for driving respective belts of the plurality of belts; and a connecting belt connecting the spooling pulleys such that the spooling pulleys are configured to spool at substantially the same rate;wherein the failure detector is configured such that failure of a connecting belt causes the detector element to move from the first position to the third position.16. The handler of any of clauses 13-15, wherein the failure detector comprises:a sensor configured to detect whether the detector element is at the first position.17. A lithography apparatus configured to transfer a pattern from a patterning device to a substrate, the lithography apparatus comprising:a patterning device load port; andthe handler of any preceding clause for moving the patterning device towards the patterning device load port.18. A lithography system comprising:the lithography apparatus of clause 17.19. A method for moving a patterning device, the method comprising:downwardly retracting a retractable rail; andactuating the patterning device upwards along the retractable rail from a manual loading height to a load port height.

[0134] The concepts disclosed herein may be associated with any generic imaging system for imaging sub wavelength features, and may be especially useful with emerging imaging technologies capable of producing increasingly shorter wavelengths. Emerging technologies already in use include EUV (extreme ultra violet), DUV lithography that is capable of producing a 193nm wavelength withthe use of an ArF laser, and even a 157nm wavelength with the use of a Fluorine laser. Moreover, EUV lithography is capable of producing wavelengths within a range of 20-5nm by using a synchrotron or by hitting a material (either solid or a plasma) with high energy electrons in order to produce photons within this range.

[0135] While the concepts disclosed herein may be used for wafer manufacturing on a substrate such as a silicon wafer, it shall be understood that the disclosed concepts may be used with any type of manufacturing system, e.g., those used for manufacturing on substrates other than silicon wafers. In addition, the combination and sub-combinations of disclosed elements may comprise separate embodiments. For example, the modular moveable loading station, and the handling system may comprise separate embodiments, and / or these features may be used together in the same embodiment.

[0136] 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 as described without departing from the scope of the claims set out below.

Claims

CLAIMS1. A handler for moving a patterning device, the handler comprising:a retractable rail; andan actuator configured to actuate the patterning device upwards along the retractable rail from a manual loading height to a load port height;wherein the retractable rail is upwardly retractable.

2. The handler of claim 1, wherein:the handler comprises a telescopic assembly comprising the retractable rail;the telescopic assembly comprises:an upper rail; andthe retractable rail slidable along the upper rail; andthe upper rail is substantially parallel to the retractable rail.

3. The handler of claim 1, comprising:a rail lock configured to controllably lock the retractable rail in its retracted state.

4. The handler of claim 1 , comprising:a patterning device support configured to support the patterning device, wherein the patterning device support is slidable along the retractable rail, and wherein the actuator is configured to actuate the patterning device support upwards, so as to actuate the patterning device upwards along the retractable rail from the manual loading height to the load port height.

5. The handler of claim 1, wherein the retractable rail is upwardly retractable such that when the retractable rail is retracted, the handler is above the manual loading height.

6. The handler of claim 1 , wherein the actuator comprises a pulley system configured to lift the patterning device.

7. The handler of claim 6, wherein the pulley system comprises a plurality of belts, each belt configured to lift the patterning device upwards along the retractable rail, so as to provide redundancy.

8. The handler of claim 7, comprising:a failure detector configured to detect a failure of the pulley system.

9. The handler of claim 8, wherein the failure detector is configured to detect a failure of at least one of the plurality of belts.

10. The handler of claim 9, wherein the failure detector is configured such that failure of a first belt of the plurality of belts causes a detector element to move from a first position to a second position.

11. The handler of claim 10, wherein the failure detector is configured such that failure of a second belt of the plurality of belts causes the detector element to move from the first position to a third position.

12. The handler of claim 11, wherein the pulley system comprises:a plurality of spooling pulleys for driving respective belts of the plurality of belts; and a connecting belt connecting the spooling pulleys such that the spooling pulleys are configured to spool at substantially the same rate;wherein the failure detector is configured such that failure of a connecting belt causes the detector element to move from the first position to the third position.

13. The handler of any of claim 12, wherein the failure detector comprises:a sensor configured to detect whether the detector element is at the first position.

14. A lithography apparatus configured to transfer a pattern from a patterning device to a substrate, the lithography apparatus comprising:a patterning device load port; andthe handler of any preceding claim for moving the patterning device towards the patterning device load port.

15. A method for moving a patterning device, the method comprising:downwardly retracting a retractable rail; andactuating the patterning device upwards along the retractable rail from a manual loading height to a load port height.

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