Clamping with a removable membrane in a lithography apparatus

Abstract

A clamping system is described. The clamping system includes a membrane that functions as an intermediate layer between a reticle (or a wafer) and a clamp in a lithography apparatus. This membrane can be replaced in the field if it experiences wear, for example, instead of having to replace permanent components of the clamp, which is far more difficult. Because the membrane's dimensions are similar to those of a typical reticle, the membrane can be replaced using an existing reticle handling system that is a part of the lithography apparatus. The membrane is relatively thin and compliant compared to the clamp and / or the reticle such that the membrane may be configured to first couple to the reticle and conform to a shape of the reticle, and then couple to the clamp. This way the membrane forms a known tunable interface configured for coupling the reticle to the clamp.

Description

CLAMPING WITH A REMOVABLE MEMBRANE IN A LITHOGRAPHY APPARATUSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority of US application 63 / 621,164 which was filed on 16 January 2024 and US application 63 / 657,285 which was filed on 07 June 2024 and which are incorporated herein in its entirety by reference.TECHNICAL FIELD

[0002] This description relates generally to clamping for a lithography 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 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. During pattern transfer, a reticle or a wafer may be electrostatically clamped.SUMMARY

[0004] A clamping system is described. The clamping system includes a thin membrane that functions as an intermediate layer between a reticle (or a wafer) and a clamp in a lithography apparatus. This thin membrane can be replaced in the field if it experiences wear and / or degradation, or if a superior version of the membrane or the clamp is developed (i.e., to upgrade performance of the clamp), for example, instead of having to replace permanent components of the clamp (or even the entire clamp), which is far more difficult. Because the membrane’s dimensions are similar to those of a typical reticle, the membrane can be replaced using an existing reticle handling system that is a part of the lithography apparatus. This facilitates replacement with minimal downtime, and has other advantages. In addition, the membrane is relatively thin and compliant compared to the clamp and / or the reticle such that themembrane may be configured to first couple to the reticle and conform to a shape of the reticle, and then couple to the clamp. This way the membrane forms a known tunable interface configured for coupling the reticle or wafer to the clamp.

[0005] According to an embodiment, there is provided a clamping system for a lithography apparatus. The clamping system comprises a base configured to provide a holding force configured to removably hold an object; and a membrane configured to be removably coupled to the base and engage the object. The membrane comprises a first surface configured to contact the base; a second, opposite surface, for engaging the object; and a coupler configured to provide a coupling force to removably couple the membrane to the object and / or the base.

[0006] In some embodiments, the base comprises a clamp configured to releasably clamp the membrane and the object. In some embodiments, the base comprises a chuck coupled to the clamp. The chuck is configured to hold the clamp, the membrane, and the object, and facilitate movement of the clamp, the membrane, and the object.

[0007] In some embodiments, the object comprises a reticle or a wafer, and the clamping system is part of a lithography apparatus used in semiconductor manufacturing.

[0008] In some embodiments, the base comprises one or more base electrodes configured to provide electrostatic force configured to removably hold the object and / or the membrane. The one or more base electrodes are configured to be energized and de-energized to provide or remove the electrostatic force. In some embodiments, the one or more base electrodes are configured to be progressively energized such that contact between the membrane and the base propagates from an initially energized contact location progressively across the membrane.

[0009] In some embodiments, the coupler is passive, having no moving parts or electrically energized components.

[0010] In some embodiments, the coupler comprises one or more electrode layers, each electrode layer comprising one or more membrane electrodes configured such that electrostatic force capacitively couples the membrane to the base and / or the object. In some embodiments, the one or more electrode layers comprise one electrode layer between the first surface and the second surface. In some embodiments, the one or more electrode layers comprise two electrode layers, with a first electrode layer located proximate to the first surface, and a second electrode layer located proximate to the second surface.

[0011] In some embodiments, the coupler comprises one or more magnets configured to provide the coupling force to removably couple the membrane to the base. In some embodiments, the coupler comprises one or more mechanical and / or vacuum components configured to provide the coupling force to removably couple the membrane to the base.

[0012] In some embodiments, the membrane is permeable to cooling gas provided from the base such that the cooling gas is provided at a first interface between the base and the membrane, and at a second interface between the membrane and the object. In some embodiments, the membrane comprisescooling gas channels configured to conduct the cooling gas from the first interface to the second interface. The cooling gas may comprise hydrogen, oxygen, nitrogen, air, and / or other cooling gases.

[0013] In some embodiments, the base comprises one or more fluid cooling channels configured to cool the base.

[0014] In some embodiments, the base comprises a contact surface with at least one portion coated with a dielectric material configured to contact the first surface. The dielectric material is configured to act as an electrically insulating barrier between one or more base electrodes and the surrounding environment. In some embodiments, the dielectric material comprises diamond, Si3N4, A12O3, SiO2, Ta2O5, TiO2, HfO2, ZrO2, and / or other materials.

[0015] In some embodiments, the base comprises a contact surface comprising an exposed metal surface configured to contact the first surface, with the exposed metal surface comprising an electrode.

[0016] In some embodiments, the membrane is configured with its own high voltage connection.

[0017] In some embodiments, the contact surface comprises a reference surface profile, and the first surface of the membrane is configured based on the reference surface profile.

[0018] In some embodiments, the base comprises one or more base electrodes configured to provide electrostatic force configured to removably hold the object. The one or more base electrodes may be configured to provide the electrostatic force to independently control clamping forces on the membrane and / or the object by selective application of voltage to the one or more base electrodes.

[0019] In some embodiments, the membrane comprises a physical or virtual ground connection configured to enhance removable coupling of the membrane to the base and / or the object.

[0020] In some embodiments, the system comprises a tool handler including a reticle handler turret gripper and a reticle handler robot gripper. The reticle handler robot gripper is configured to move the membrane and / or the object from a load port of a lithography apparatus. The reticle handler turret gripper is configured to position the membrane for contacting the base, and / or the object.

[0021] In some embodiments, the tool handler comprises a membrane installation tool configured for contacting the membrane to the object and / or the base. The membrane installation tool may comprise a surface and / or end stops configured to support the membrane in a contacting position. In some embodiments, the membrane installation tool comprises one or more magnets configured to attract the membrane against the surface during installation and / or removal. In some embodiments, the membrane installation tool comprises a contour configured to shape the surface such that a center of the membrane first contacts the object and / or the base during installation. In some embodiments, the membrane installation tool comprises one or more installation electrodes configured to provide electrostatic force configured to removably hold the membrane during installation and / or removal.

[0022] In some embodiments, the first surface comprises first burls configured to contact the base, the first burls protruding from the first surface toward the base; or the base comprises the first burls, with the first burls protruding from the base toward and configured to contact the first surface. In some embodiments, the second surface comprises second burls for engaging the object, with the second burlsprotruding from the second surface. In some embodiments, the first burls and / or second burls comprise flexible pillars configured for a van der Waals, Johnsen-Rahbek, and / or capillary adhesion interaction with the base and / or the object.

[0023] In some embodiments, the membrane is relatively thin and compliant compared to the base and / or the object. The membrane may be configured to first couple to the object and conform to a shape of the object, and then couple to the base. In some embodiments, the membrane forms a known tunable interface configured for coupling the object to the base.

[0024] In some embodiments, the membrane and the base are mechanically separate when the membrane couples to the object. Mechanically separate may comprise not touching at all, deformable relative to each other, flexible relative to each other, and / or loosely connected to each other. In some embodiments, the membrane and the base are mechanically connected, while still allowing the membrane to move independently, during clamping.

[0025] In some embodiments, an interface between the membrane and the base is relatively low friction compared to another interface between the membrane and the object, when the membrane is coupled to the object. In some embodiments, a friction level at the interface between the membrane and the base is adjustable to provide the relatively low friction when the membrane is coupled to the object, and relatively high friction to clamp the membrane and the object to the base. In some embodiments, the friction level at the interface between the membrane and the base is adjustable using electrostatic charges, lubrication, specifics shapes of surfaces of the membrane and / or the base, areal friction distribution, capillary clamping, mechanical flexures, locally confined gasses and / or liquids, surface roughness, and / or using other techniques.

[0026] In some embodiments, the membrane comprises a plurality of sub portions interconnected by flexible couplers. The plurality of sub portions is interconnected by the flexible couplers configured to at least in part facilitate relative compliance of the membrane compared to the base and / or the object. The relative compliance of the membrane may cause the membrane to conform to a topology of the object when the membrane is coupled to the object.

[0027] In some embodiments, the flexible couplers comprise relatively thinner areas of the membrane compared to relatively thicker areas which form the plurality of sub portions.

[0028] In some embodiments, each of the plurality of sub portions comprises one or more burls configured to contact the object, with minimal lateral shear between each burl and the object because of the relative compliance of the membrane.

[0029] In some embodiments, each of the plurality of sub portions has a square, rectangular, hexagonal, octagonal, round, and / or other shapes.

[0030] In some embodiments, the holding force and / or the coupling force is an electrostatic force, a mechanical force, a vacuum force, a magnetic force, a chemical force, and / or other forces. The electrostatic force may be coulombic or Johsen-Rahbek based, for example.

[0031] In some embodiments, the membrane is configured to facilitate relatively low friction duringobject and membrane loading to the base, to prevent in-plane deformations; and facilitate relatively high friction during semiconductor lithography exposure, to prevent the object from slipping during acceleration and local heating.

[0032] In some embodiments, the thermal conductivity of the membrane is relatively low compared to the base and / or the object.

[0033] In some embodiments, the membrane comprises burls, with intermediate areas comprising a relatively soft material compared to the burls.

[0034] According to another embodiment, the membrane is provided (e.g., without the base or other components).

[0035] According to another embodiment, there is provided an electrostatic clamping method. The method comprises one or more operations performed by the electrostatic clamping system and / or the membrane described above.

[0036] According to another embodiment, there is provided a method for manufacturing the membrane.BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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.

[0038] Fig. 1 schematically depicts a lithography apparatus, according to an embodiment.

[0039] Fig. 2 schematically depicts an embodiment of a lithographic cell or cluster, according to an embodiment.

[0040] Fig. 3A illustrates a portion of an extreme ultra violet (EUV) lithographic apparatus, according to an embodiment.

[0041] Fig. 3B illustrates a portion of a deep ultra violet (DUV) lithographic apparatus, according to an embodiment.

[0042] Fig. 4 illustrates a clamping system (for a lithography apparatus), according to an embodiment.

[0043] Fig. 5 illustrates different possible examples of a membrane of the electrostatic clamping system, according to an embodiment.

[0044] Fig. 6 illustrates an example of a membrane installation tool, according to an embodiment.

[0045] Fig. 7 illustrates an example embodiment of the membrane installation tool comprising a contour configured to shape a surface of the membrane installation tool, according to an embodiment.

[0046] Fig. 8 illustrates another view of various components of the electrostatic clamping system, according to an embodiment.

[0047] Fig. 9 illustrates base electrodes configured to provide electrostatic force to independently control clamping forces on the membrane and / or an object, and release of the object, by selectiveapplication of voltage to the one or more base electrodes, according to an embodiment.

[0048] Fig. 10 illustrates the membrane comprising a physical or virtual ground connection configured to enhance removable coupling and release of the membrane to the base and / or the object, according to an embodiment.

[0049] Fig. 11 illustrates how, in some embodiments, the membrane installation tool comprises one or more installation electrodes configured to provide a second electrostatic force configured to removably hold the membrane during installation and / or removal, according to an embodiment.

[0050] Fig. 12 illustrates another clamping system (for a lithography apparatus), according to an embodiment.

[0051] Fig. 13 provides another view of a membrane that is part of the clamping system shown in Fig. 12, according to an embodiment.

[0052] Fig. 14 illustrates yet another clamping system (for a lithography apparatus), according to an embodiment.

[0053] Fig. 15 illustrates a clamping method, according to an embodiment.

[0054] Fig. 16 is a block diagram of an example computer system, according to an embodiment.DETAILED DESCRIPTION

[0055] 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. Various masks are fed into a lithographic apparatus and used to form layers of a semiconductor device on a substrate such as a wafer. 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 fed into a lithographic apparatus during manufacturing and used to form corresponding layers of a semiconductor device. The same is true for wafers. A clamp (e.g., an electrostatic reticle clamp) in the lithographic apparatus is used to secure a mask or reticle during processing. Similar clamps may be used to clamp a substrate such as a semiconductor wafer and / or other objects.

[0056] In existing reticle or wafer clamps, the clamp interfaces directly with the reticle or wafer using a pattern of raised burls that are integral to the structure of the clamp. The burls are subject to wear (loss of material, accumulation of contamination, etc.) which leads to performance issues over time (e.g., overlay performance loss, ‘sticking’ of reticles, and other issues). Resolving those performance issues typically requires cleaning and / or reconditioning of the clamp surface, or replacement of the entire clamp, both of which can be time consuming. A reticle stage, for example, uses a clamp that is integral to a short stroke movement mechanism in the lithographic apparatus, and cannot currently be replaced in the field without replacing the rest of the short stroke movement mechanism. For wafer stages, the clamp can technically be replaced in the field, though replacement is a long and costly operation.

[0057] Replacing clamps in the field has several disadvantages including the expense of the operation;long factory cycle times for replacement parts (which makes replacement parts less available and more difficult to obtain); partial disassembly and then recovery of the lithographic apparatus, which can take several days to complete; etc.. The double-sided clamp construction used by wafer stages also has disadvantages including the presence of one extra clamped interface that must carry the combined mass / inertia of the clamp and wafer. In the case of the wafer clamps, this is far more inertia than the wafer alone, and therefore this secondary interface can experience high stresses and subsequent slip or wear. Double-sided clamps are more difficult to manufacture than single-sided clamps, leading to higher cycle times and cost. A double sided clamp must also have serviceable water and high voltage electrical interfaces (for an electrostatic clamp) or vacuum interfaces (for a vacuum clamp), which adds complexity to the design and replacement operations.

[0058] In addition, in existing systems a reticle or wafer is clamped on a flat clamp during a single clamping action. Friction between the clamp and the reticle or wafer is important. The ideal friction between the reticle or wafer and the clamp is a balance: low friction is desirable during reticle or wafer loading, to prevent in-plane deformations; but high friction is desirable, during lithography, so that the reticle or wafer does not slip during acceleration and / or local heating. High friction during lithography is also desirable because slip between clamp burls and the reticle or wafer can cause wear and / or particle discharge. It is difficult to predict and / or control the friction between the reticle or wafer and the clamp because the friction depends on several (sometimes unpredictable) reticle or wafer backside properties (e.g., material properties, roughness, surface treatments, , etc.), for example.

[0059] A new clamping system is described herein. The clamping system includes a thin membrane that is used as an intermediate layer between the reticle (or wafer) and the clamp. This thin membrane can be replaced in the field if it experiences wear and / or degradation, or if a superior version of a clamp and / or the membrane is developed (i.e., to upgrade performance of the clamp). In addition, because the membrane’s dimensions are similar to the dimensions of a reticle (e.g., as described below), the membrane can be replaced using the existing reticle handling system that is a part of a typical lithographic apparatus. This facilitates replacement with minimal lithographic apparatus downtime. Further, because the membrane can be thin (around or less than 1mm), the membrane’s mass is much less than the mass of an entire clamp. For example, a 1mm thick membrane weighs about 50 g, which is about 10% of the mass of a reticle (for example) clamp, and about 16% of the mass of a reticle. As a result, the additional clamped interface carries only marginally more mass than a typical baseline reticle clamp, and so generally does not affect the typical operation of a lithographic apparatus, even though is a new and separate component. Furthermore, the membrane is relatively thin and compliant compared to the clamp and / or the reticle or wafer such that the membrane may be configured to first couple to the reticle and conform to a shape of the reticle or wafer, and then couple to the clamp. This way the membrane forms a known tunable interface configured for coupling the reticle or wafer to the clamp. Other advantages are contemplated.

[0060] 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 detection patterns 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.”

[0061] 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, after which the individual devices can be mounted on a carrier, connected to pins, etc.

[0062] Manufacturing devices, such as 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 lithographic 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.

[0063] 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.

[0064] Fig. 1 schematically depicts an embodiment of a lithographic apparatus LA that may include and / or associated with the present systems and / or methods. The apparatus comprises: an illuminationsystem (illuminator) IL configured to condition a radiation beam B (e.g. UV radiation, DUV radiation, or EUV radiation); a support structure (e.g. a mask table) MT constructed to support a patterning device (e.g. a mask) MA and 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).

[0065] The illuminator IL receives a beam of radiation from a radiation source SO. The source and the lithographic 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 lithographic 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.

[0066] 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.

[0067] 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., byinserting an optic which provides that illumination mode into the illuminator IL or using a spatial light modulator.

[0068] The illuminator IL may be operable to alter the polarization of the beam and may be operable to adjust the polarization using adjuster AD. 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.

[0069] The support structure MT supports the patterning device in a manner that depends on the orientation of the patterning device, the design of the lithographic 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.

[0070] 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. In an embodiment, a patterning device is any device that can be used to impart a radiation beam with a pattern in its crosssection to create a pattern in a target portion of the substrate. It should be noted that the pattern imparted to the radiation beam 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.

[0071] A patterning device may be transmissive or reflective. Examples of patterning devices include reticles or masks, programmable mirror arrays, and programmable LCD panels. Reticles or masks are well known in lithography, and include mask types such as binary, alternating phase-shift, and attenuated phase-shift, as well as various hybrid mask types. An example of a programmable mirror array employs a matrix arrangement of small mirrors, each of which can be individually tilted to reflect an incoming radiation beam in different directions. The tilted mirrors impart a pattern in a radiation beam, which is reflected by the mirror matrix.

[0072] 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 beoperable 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.

[0073] The lithographic 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.

[0074] In operation of the lithographic 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., 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 and position 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 shortstroke 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.

[0075] The depicted apparatus may be used in a step mode and / or a 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.

[0076] 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 or inspection tool. Where applicable, the disclosure herein may be applied to such and other substrate processing tools. Further, the substrate may be processed more than once, for example in order to create a multi-layer IC, so that the term substrate used herein may also refer to a substrate that already includes multiple processed layers.

[0077] The terms “radiation” and “beam” used herein 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.

[0078] 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.

[0079] As shown in Fig. 2, the lithographic apparatus LA may form part of a lithographic cell LC, also sometimes referred to as a lithocell or cluster, which also includes apparatuses to perform pre- and postexposure 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 lithographic 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 lithographic apparatus via lithography control unit LACU. Thus, the different apparatuses can be operated to maximize throughput and processing efficiency.

[0080] In order to ensure that a substrate that is exposed by the lithographic 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 a same 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 lithographic apparatus LA (such as alignment sensor AS (Fig. 1)).

[0081] 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 anoptical 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.

[0082] Thus, in a device fabrication process (e.g., a patterning process, a lithography process, etc.), a substrate or other objects may be subjected to various types of measurement during or after the process. The measurement may determine whether a particular substrate is defective, may establish adjustments to the process and apparatuses used in the process (e.g., aligning two layers on the substrate or aligning the patterning device to the substrate), may measure the performance of the process and the apparatuses, or may be for other purposes. Examples of measurement include optical imaging (e.g., optical microscope), non-imaging optical measurement (e.g., measurement based on diffraction such as the ASML YieldStar metrology tool, the ASML SMASH metrology system), mechanical measurement (e.g., profiling using a stylus, atomic force microscopy (AFM)), and / or non-optical imaging (e.g., scanning electron microscopy (SEM)).

[0083] 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.

[0084] Within a metrology system, a metrology apparatus is used to determine one or more properties 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 lithographic apparatus LA or the lithocell LC or may be a stand-alone device.

[0085] To enable the metrology, one or more targets can be provided on the substrate. In an embodiment, the target is specially designed and may comprise a periodic structure. In an embodiment, the target is a part of a device pattern, e.g., a periodic structure of the device pattern. In an embodiment, the device pattern is a periodic structure of a memory device (e.g., a Bipolar Transistor (BPT), a Bit Line Contact (BLC), etc. structure).

[0086] 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.

[0087] As described above, an electrostatic clamping system may be used in a lithographic and / or metrology apparatus to clamp an object such as a patterning device (e.g., a reticle), a substrate such as a wafer, and / or other objects. Before clamping, the lithographic apparatus (for example) may move theobject through typical movements and / or positions of a reticle to clamping position.

[0088] By way of a non-limiting example, Fig. 3A and Fig. 3B illustrate example portions of lithographic apparatus 300 (e.g., similar to an or the same as the lithographic apparatus shown in Fig. 1). Fig. 3A illustrates a portion of an extreme ultra violet (EUV) lithographic apparatus. Fig. 3B illustrates a portion of a deep ultra violet (DUV) lithographic apparatus.

[0089] Fig. 3A illustrates an example embodiment of an object 302 (e.g., in transit to and / or in proximity to a clamp 312 of lithographic apparatus 300) and various components of lithographic apparatus 300 including a tool handler and / or other components. Object 302 (e.g., a reticle in this example) is configured to be brought into apparatus 300 using a reticle pod. Object 302 is secured from the outside environment in an inner pod. Object 302 in the inner pod is placed on an EUV inner pod baseplate. Object 302 is moved from outside vacuum through the reticle handling system on to the turret of a tool handler of lithographic apparatus 300.

[0090] In some embodiments, lithographic apparatus 300 can be configured for deep ultraviolet (DUV) lithography with one or more adjustments from what is shown in Fig. 3A. Fig. 3B illustrates an example DUV apparatus with object 302 (e.g., in transit to and / or from a clamp 312 of lithographic apparatus 300 in these figures) and various components of lithographic apparatus 300 including a tool handler, reticle stage 310, reticle clamp(s) 312, and / or other components.

[0091] In some embodiments, the tool handler comprises a reticle handler turret gripper 306, a reticle handler robot gripper 307 (having associated components 308, etc. for gripping a reticle during transport), and / or other components. Reticle handler robot gripper 307 may, for example, move a reticle from a pod 320 (e.g., after a user places a reticle in pod 320). Reticle handler turret gripper 306 may, for example, move a reticle from reticle handler robot gripper 307 to reticle clamp(s) 312. Lithographic apparatus 300 may include various other mechanical components 322 (translation mechanisms, elevation mechanisms, rotational mechanisms, motors, power generation and transmission components, structural components, etc.) configured to facilitate movement and control of object 302 through lithographic apparatus 300. Object 302 is configured to be clamped by clamp(s) 312 (e.g., reticle clamp(s)) of lithographic apparatus 300.

[0092] Fig. 4 illustrates a clamping system 400. In this example, system 400 is an electrostatic clamping system. System 400 comprises a base 402, a membrane 404, and / or other components. Base 402 comprises one or more electrodes 401, cooling water channels 412, and / or other components. The one or more electrodes 401 provide electrostatic force configured to removably hold an object 406 (e.g., a reticle or mask, a substrate such as a semiconductor wafer, and / or other objects). In some embodiments, base 402 comprises a clamp 408 configured to releasably clamp membrane 404 and / or object 406 via a contact surface 420. The surface or body of object 406 is sufficiently electrically conductive for an electrostatic clamp to function for the embodiments described herein based on electrostatic clamping (i.e., if it is made of an insulating material like glass reticles are, then it needs a metallic or semiconducting coating).

[0093] Contacting may include touching, nearly touching, and / or other contacting. In some embodiments, the contacting is controlled by one or more processors, via the reticle handler turret gripper, and / or using other components of a lithography apparatus (e.g., as described herein). One or more electrodes 401 are coupled to contact surface 420. A charge propagates through an electrode 401 such that an opposite polarity is induced in a side of membrane 404 and / or a clamped object 406 configured to contact surface 420. An electrode 401 may be energized with a voltage of about 1000V- 7000V, for example, and / or other voltages.

[0094] In some embodiments, base 402 comprises a chuck 410 coupled to clamp 408. Chuck 410 is configured to hold clamp 408, membrane 404, and / or object 406, and facilitate movement of clamp 408, membrane 404, and / or object 406. For example, chuck 410 may be a short stroke (e.g., reticle) stage or module chuck in a lithography apparatus such as lithography apparatus LA shown in Fig. 1 and / or lithographic apparatus 300 shown in Fig. 3A.

[0095] In some embodiments, base 402 comprises contact surface 420, with at least some portions coated with a dielectric material configured to contact a first surface 430 (e.g., a base 402 facing surface) of membrane 404. The dielectric material is configured to act as an electrically insulating barrier between one or more base electrodes 401 and the surrounding environment. In some embodiments, base 402 is configured such that contact surface 420 comprises an exposed metal surface configured to contact first surface 430, with the exposed metal surface comprising an electrode 401. Membrane 404 may be configured with or without its own high voltage connection based on whether base 402 has the dielectric material or an exposed metal surface. In some embodiments, the dielectric material comprises diamond, Si3N4, A12O3, SiO2, Ta2O5, TiO2, HfO2, ZrO2, and / or other dielectric materials.

[0096] In some embodiments, contact surface 420 comprises a reference surface profile, and first surface 430 of membrane 404 is configured based on the reference surface profile. For example, in the example shown in Fig. 4, contact surface 420 has a substantially flat reference surface profile, and first surface 430 is configured accordingly. However, other configurations are contemplated.

[0097] Membrane 404 may have dimensions similar to the dimensions of a reticle or wafer. For example, membrane 404 may have a length of about 100-300 mm, a width of about 100-300 mm, a thickness (“t” shown in the side view of system 400 in Fig. 4) of about 1mm or less, and / or area of about 10000 - 90000 mm2. For this reason, the membrane can be replaced using the existing reticle handling system (e.g., as described above with respect to Fig. 3 A - see reticle handler turret gripper 306, and reticle handler robot gripper 307) or wafer handling system that is a part of a typical lithographic apparatus. This facilitates replacement with minimal lithographic apparatus downtime and / or has other advantages.

[0098] Membrane 404 may be made from several different materials. Low thermal expansion, low mass, and high stiffness are all desirable properties in membrane 404. In some embodiments, membrane 404 may be made from an insulating material. In some embodiments, membrane 404 may be made from a conducting material. Example materials that may be used for membrane 404 may include butare not limited to silicon dioxide (SiO2 - fused silica, quartz), low thermal expansion materials, ultralow thermal expansion materials (e.g., titanium doped SiO2), silicon carbide (SiC), diamond-SiC composites, and / or other materials. In some embodiments, membrane 404 may have an engineered stiffness (i.e. flexures, relief cuts, etc.) that reduces the stress from thermal expansion and contraction, for example. In some embodiments, membrane 404 may be fabricated using technology similar to that used to fabricate electrostatic clamps (e.g., bonding several layers of glass, and using coating, etching and laser etching processes), and / or may be fabricated using wafer processing technology (e.g., wafer polishing, coating, etching) before cutting a final shape.

[0099] Membrane 404 comprises the first surface 430, which is configured to contact base 402; a second, opposite surface 440, for engaging object 406; a coupler 450 configured to provide a coupling force to removably couple membrane 404 to base 402 (and / or object 406 to membrane 404); and / or other components. Coupler 450 is passive, having no moving parts or electrically energized components. In some embodiments, first surface 430 comprises first burls 431 configured to contact base 402, with first burls 431 protruding from first surface 430 toward base 402. In some embodiments, base 402 comprises the first burls, with the first burls protruding from base 402 toward and configured to contact first surface 430 (though this is not specifically shown in Fig. 4). Second surface 440 may comprise second burls 441 for engaging object 406, with second burls 441 protruding from second surface 440. In some embodiments, first burls 431 and / or second burls 441 may not be included at all, and instead first surface 430, second surface 440, contact surface 420, and / or a surface of object 406 may be figured for other types of contact.

[0100] In some embodiments, first burls 431 and / or second burls 441 comprise dome and / or other shaped protrusions from a given surface. In some embodiments, first burls 431 and / or second burls 441 comprise flexible pillars configured for a van der Waals, Johnsen-Rahbek, capillary adhesion, and / or other interaction with base 402 and / or object 406, respectively, and / or other components. The flexible pillars may have ends and / or tips shaped (e.g., wedge shaped, mushroom shaped, etc.) to grip an opposing surface, for example. In general first burls 431 and / or second burls 441 may have any shape and / or size that allows system 400 to function as described herein.

[0101] Fig. 5 illustrates different possible example embodiments 500 and 502 of membrane 404. In some embodiments, coupler 450 of membrane 404 comprises one or more electrode layers 510. Each electrode layer 510 comprises one or more membrane electrodes 520 configured such that the electrostatic force capacitively couples membrane 404 to the base (e.g., base 402 shown in Fig. 4) and / or the object (e.g., object 406 shown in Fig. 4). In example embodiment 502, the one or more electrode layers 510 comprise one electrode layer 510 between first surface 430 and second surface 440. Embodiment 502 may provide a simpler design, with better thermal performance and / or other advantages. Membrane 404 may be about 0.2mm thick, for example, in embodiment 502. In some embodiments, a conductive layer may be thick enough to provide structural support (e.g., a conductive wafer). In example embodiment 500, the one or more electrode layers 510 comprise two electrodelayers 510, with a first electrode layer 510 located proximate to first surface 430, and a second electrode layer 510 located proximate to second surface 440. In embodiment 500 membrane 404 may be about 1mm thick, for example.

[0102] In some embodiments, coupler 450 comprises one or more magnets configured to provide the coupling force to removably couple membrane 404 to the base. In some embodiments, coupler 450 comprises one or more mechanical components (e.g., a tight fitting pin on membrane 404 for a corresponding sleeve in the base, a slot, a clip, a clamp, adhesive, and / or other retaining features) configured to provide the coupling force to removably couple membrane 404 to the base. In general, membrane 404 may comprise any number or type of features configured to retain membrane 404 against gravity when system 400 (Fig. 4) is powered off and / or at other times. For example, magnetic or mechanical (e.g. clips, slots) retaining features. With permanent magnets, the corresponding interface may comprise a passive component (e.g., a permanent magnet or ferromagnetic material), or may be active (e.g., an electromagnet) so that magnetic force can be varied to support against gravity during membrane 404 loading (as described herein), in addition to retaining membrane 404 during normal operation. Other configurations are contemplated.

[0103] As described above, membrane 404 may be moved with a tool handler including a reticle handler turret gripper and a reticle handler robot gripper (of the lithography apparatus). The reticle handler robot gripper is configured to move the membrane and / or the object from a load port of a lithography apparatus, and the reticle handler turret gripper is configured to position the membrane for contacting the base, and / or the object for contacting the membrane (see discussion of reticle handler turret gripper 306, and reticle handler robot gripper 307 in lithography apparatus 300 shown in Fig. 3A). Loading and unloading membrane 404 may make use of similar existing techniques for loading and unload wafers and / or reticles (e.g. including using hydrogen gas), including using alignment techniques for these components.

[0104] In some embodiments, the tool handler comprises a membrane installation tool configured for contacting membrane 404 (see Fig. 4 and Fig. 5) to the base (e.g., base 402 shown in Fig. 4). Fig. 6 illustrates example embodiments 602 and 604 of a membrane installation tool 600. Membrane installation tool 600 comprises a surface 610, end stops 612, and / or other components configured to support membrane 404 in a contacting and / or a removal position. The contact and / or removal position may be a position proximate to the base, so that membrane 404 may be attracted to and / or released from the base for installation or removal. In this example, surface 610 is a flat surface that is generally sized to be at least slightly larger than membrane 404. Also in this example, end stops 612 comprise one (e.g., a single end stops could be a continuous piece that surrounds membrane 404) or more rectangular or cubic pieces of material positioned proximate to membrane 404 the so that end stops prevent significant side to side movement of membrane 404 before or after installation or removal. It some embodiments, surface 610 and end stops 612 form a single integral piece. In some embodiments, they are separate components. In general, surface 610, end stops 612, and / or other components, may haveany size and / or shape, and / or may be made from any material that allows them to function as described herein.

[0105] In some embodiments, membrane installation tool 600 comprises (as shown in embodiment 604) one or more magnets 620 configured to attract membrane 404 (Fig. 4 and Fig. 5) against surface 610 during installation and / or removal. During installation, magnetic force provided by magnets 620 may be overcome by an attractive force from base electrodes (e.g., as described above - see Fig. 4). During removal, magnetic force from magnets 620 may be used to pull membrane 404 off of the base and onto membrane installation tool 600. Gas pressure from gas flowing through or otherwise from the base may also be used to push membrane 404 off of the base, for example (gas flow is further described below). In some embodiments, surface 610, end stops 612, magnets 620, and / or other components may be configured to self-center membrane 404 on membrane installation tool 600 for installation and / or removal.

[0106] In some embodiments, membrane installation tool 600 comprises a contour configured to shape surface 610 such that a center of membrane 404 (Fig. 4 and Fig. 5) first contacts the base (e.g., base 402 shown in Fig. 4) during installation. The contour may facilitate conformal contact between membrane 404 and base 402 during installation, for example. The contour may also facilitate repeatable and / or otherwise controlled (e.g., in combination with electromagnets and / or other components) contact with surface 610 during removal, and / or have other purposes.

[0107] Fig. 7 illustrates an example embodiment 700 of membrane installation tool 600 comprising a contour 702 configured to shape surface 610. Contour 702 is configured such that a center of membrane 404 first contacts base 402. In this example, contour 702 has a generally triangular or pyramid like shape, but this is not intended to be limiting. Contour 702 may have any shape that allows membrane installation tool 600 to function as described herein.

[0108] In some embodiments, base 402 and / or base electrode(s) 401 are configured to clamp membrane 404 in a way that facilitates local stress relaxation in membrane 404 as contact occurs progressively across membrane 404. For example, electrode(s) 401 may be configured to progressively energize portions of contact surface 420 such that contact between membrane and contact surface 420 propagates from an initially energized contact location 710 (e.g., at or near a center of membrane 404 progressively across contact surface 420. Energizing means that this area becomes active in the clamping process, for example. Contact between membrane 404 and contact surface 420 may propagate from initially energized contact location 710 at a rate that facilitates local stress relaxation in membrane 404 as contact occurs progressively across surface 420.

[0109] In some embodiments, membrane 404 is permeable to cooling gas provided from base 402. In this example, cooling gas is provided through cooling gas channels 720 in base 402 (noting that one or more fluid (e.g., gas or liquid) cooling channels 412 and / or 720 may be provided in the base to cool base 402 and / or membrane 404). The cooling gas may be provided at a first interface 750 between base 402 and membrane 404, and at a second interface 755 (see Fig. 4 and Fig. 8) between membrane 404and the object (e.g., object 406 shown in Fig 4). In some embodiments, membrane 404 comprises cooling gas channels 760 configured to conduct the cooling gas from first interface 750 to second interface 755. In some embodiments, the cooling gas comprises hydrogen, oxygen, nitrogen, air, and / or other cooling gases. In some embodiments, other functionality can also be incorporated into membrane 404. For example, membrane 404 may comprise active elements that allow it to deform the shape of an object 406 (Fig. 4) such as a reticle (e.g. piezo electric elements, micro electro mechanical system (MEMS) based devices, local heating elements, and / or other mechanisms), object (reticle) cooling technology (e.g. thermoelectric coolers, gas / fluid channels, restrictions and orifices), and / or other functional elements.

[0110] Fig. 8 illustrates another view of various components of electrostatic clamping system 400. For example, Fig. 8 illustrates base 402 (comprising clamp 408 and chuck 410 fusion bonded 800 together in this example), membrane 404, object 406 (e.g., a reticle or mask, a substrate such as a semiconductor wafer, and / or other objects), a cooling water channel 412, cooling gas channels 720 (through base 402), cooling gas channels 760 (through membrane 404), first interface 750, second interface 755, electrode(s) 401, and / or other components. In this example, water may flow through cooling water channel 412, and hydrogen (H2) may be used as the cooling gas. In this example, fusion bonding 800 eliminates several water-carrying components (e.g., Z-plugs).

[0111] System 400 is configured such that membrane 404 is able to be removably coupled to base 402, and object 406 is able to be engaged (and released). One or more base 402 electrode(s) 401 are configured to be energized and de-energized to provide or remove the electrostatic force (to removably couple membrane 404 and / or engage object 406). In some embodiments, this may include progressively energizing the one or more base electrodes 401 such that contact between membrane 404 and base 402 propagates from an initially energized contact location progressively across membrane 404 (e.g., as described above). In some embodiments, membrane 404 comprises a physical or virtual ground connection configured to enhance removable coupling of membrane 404 to base 402 and / or object 406. In some embodiments, the one or more base 402 electrodes 401 are configured to provide the electrostatic force to independently control clamping forces on membrane 404 and / or object 406 by selective application of voltage to the one or more base electrodes 401.

[0112] For example, Fig. 9 illustrates base 402 electrodes 401 configured to provide the electrostatic force to independently control clamping 900 forces on membrane 404 and / or object 406, and release 902 of object 406, by selective application of voltage to the one or more base electrodes 401. In this example, +2kV and -2kV are selectively applied (i.e., left versus right side of base 402) to electrodes 401 for clamping 900, such that -1-lkV and -IkV are induced in membrane 404 electrodes 520, and a clamping force from IkV deltas 910 and 912 is induced between base 402 and membrane 404, and membrane 404 and object 406, respectively. In some embodiments, object 406 may have an applied 0V. In some embodiments, object 406 can be electrically floating / isolated instead of having an applied 0V. If object 406 is electrically floating, charges redistribute laterally along a metallic orsemiconducting surface of object 406 so that the surface will reach a 0V potential on its own. Clamping force may be adjusted by providing more or less than + / - 2kV to electrodes 401 (+ / - 2kV is used as one possible example in Fig. 9). For release 902, only +lkV and -IkV are (differently selectively - i.e., every other) applied to electrodes 401 (while 0V are still applied to object 406), such that 0V are induced in membrane 404 electrodes 520, and there is clamping force between base 402 and membrane 404 (because there is still a IkV delta 920), but not between membrane 404 and object 406 (because there is no longer a delta between membrane 404 and object 406).

[0113] Fig. 10 illustrates membrane 404 comprising a physical or virtual ground connection 1010 (noted by “g” in Fig. 10) configured to enhance removable coupling 1000 and release 1002 of membrane 404 to base 402 and / or object 406. In this example, again +2kV and -2kV are selectively applied (i.e., left versus right side of base 402) to electrodes 401 for clamping (e.g., coupling 1000), while 0V are applied to object 406, such that +lkV and -IkV are induced in membrane 404 electrodes 520, and a clamping force from deltas 1020 and 1022 is induced between base 402 and membrane 404, and membrane 404 and object 406, respectively. For release 1002, only +lkV and -IkV are (differently selectively - i.e., every other) applied to electrodes 401 (while 0V are still applied to object 406), and electrodes 520 comprise a ground connection 1010, such that there is clamping force between base 402 and membrane 404 (because there is still a IkV delta 1030), but not between membrane 404 and object 406 (because membrane 404 is essential shielding object 406). A physical ground, for example, could be made by some separate connection to ground (e.g. an exposed metal pin between 402 and 404 that would contact each other, and then that pin can be grounded or left open. In some embodiments, one or more electrodes 520 may be conditionally connected via a switch or some other mechanism to control the clamping force applied to object 406 (e.g., a delta kV between base 402 and object 406). A physical ground connection can also be used to apply a bias voltage to object 406 (e.g., 0-100V) instead of an electrical ground.

[0114] Fig. 11 illustrates how, in some embodiments, the membrane installation tool 600 comprises one or more installation electrodes 1100 configured to provide a second electrostatic force configured to removably hold membrane 404 during installation and / or removal. Fig. 11 illustrates membrane installation tool 600 in proximity 1102 to membrane 404, and removing 1104 membrane 404. In this example, when membrane installation tool 600 is in proximity 1102 to membrane 404, +lkV and -IkV are selectively applied (i.e., left versus right side of base 402) to electrodes 401 for clamping membrane 404 to base 402, while installation electrodes 1100 are in a neutral state (0V), such that OkV are induced in membrane 404 electrodes 520, and a clamping force from IkV delta 1120 is induced between base 402 and membrane 404 (and there is no attraction to membrane installation tool 600). For removing 1104 membrane 404, voltage to base 402 electrodes 401 is turned off (OkV), and +lkV and -IkV are (differently selectively - i.e., every other) applied to installation electrodes 1100, so that membrane 404 is attracted to membrane installation tool 600 by a clamping force between membrane installation tool 600 and membrane 404 because there is a IkV delta 1130 therebetween. As described above, magnetsmay be used to supplement the attraction between base 402 and membrane 404, gas may be used to aid removal of membrane 404 from base 402, and / or other operations may be performed, as described herein to facilitate membrane 404 removal without breaking the vacuum associated with the lithography apparatus (e.g., lithography apparatus LA shown in Fig. 1 , lithography apparatus 300 shown in Fig. 3A).

[0115] Fig. 12 illustrates another clamping system 1200 (for a lithography apparatus). System 1200 may be similar to and / or the same as system 400 shown in Fig. 4. However, in this example, system 1200 may or may not be an electrostatic clamping system. System 1200 comprises a base 1202 (which may be similar to and / or the same as base 402 shown in Fig. 4), a membrane 1204 (which may be similar to and / or the same as membrane 404 shown in Fig. 4), and / or other components. Base 1202 may comprise a clamp 1208 (which may be similar to and / or the same as clamp 408 shown in Fig. 4) comprising one or more electrodes and / or other components configured to provide a holding force. Base 1202 and clamp 1208 may themselves be separated and / or held together using electrostatic, vacuum, magnetic, capillary, and / or other forces (e.g., from a second clamp). The holding force is configured to removably hold an object 1206 (e.g., a reticle or mask, a substrate such as a semiconductor wafer, and / or other objects). The holding force may be an electrostatic force, a mechanical force, a vacuum force, a magnetic force, a chemical force, and / or other forces.

[0116] Membrane 1204 is configured to be removably coupled to base 1202 and engage object 1206. Membrane 1204 may comprise a coupler 1250 (which may be similar to and / or the same as coupler 450 shown in Fig. 4) configured to provide a coupling force to removably couple membrane 1204 to object 1206 and / or base 1202, and / or other components. Coupler 1250 comprises one or more electrical, mechanical, vacuum, and / or other components configured to provide the coupling force to removably couple membrane 1204 to object 1206, and / or base 1202 (e.g., as described above). The coupling force may be an electrostatic force, a mechanical force, a vacuum force, a magnetic force, a chemical force, and / or other forces.

[0117] As illustrated in Fig. 12, membrane 1204 is relatively thin and compliant compared to base 1202 and / or object 1206. In some embodiments, membrane 1204 is configured to first couple to object 1206 and conform to a shape of object 1206 (e.g., which may include warpage 1260, as one possible example), and then couple to base 1202. In this way, membrane 1204 may form a known tunable interface 1270 configured for coupling object 1206 to base 1202. Membrane 1204 and / or interface 1270 is configured to facilitate relatively low friction during object 1206 loading, to prevent in-plane and / or other deformations; and facilitate relatively high friction during semiconductor lithography exposure, for example, to prevent object 1206 from slipping during acceleration and local heating (e.g., due to radiation impinging on the object 1206 and membrane 1204 combination, and / or other factors in a lithography apparatus).

[0118] In some embodiments, the thermal conductivity of membrane 1204 is relatively low compared to the base and / or the object. This may reduce or eliminate the local heating in membrane 1204. In addition, thermal slip between membrane 1204 and base 1202 may be reduced, and object 1206 may bethermally isolated from base 1202, which enhances performance (e.g., no second wafer effects if object 1206 is a wafer, no clamp heating, no thermal drift, etc.)

[0119] Membrane 1204 and base 1202 may be mechanically separate when membrane 1204 couples to object 1206. Mechanically separate may comprise not touching at all (e.g., as shown in Fig. 12), deformable relative to each other, flexible relative to each other, and / or loosely connected to each other, for example. However, in some embodiments, membrane 1204 and base 1202 may be mechanically connected, while still allowing membrane 1204 to move independently, during clamping.

[0120] In some embodiments, interface 1270 between membrane 1204 and base 1202 is relatively low friction compared to another interface 1280 between membrane 1204 and object 1206, when membrane 1204 is coupled to object 1206. A friction level at interface 1270 between membrane 1204 and base 1202 is adjustable to provide the relatively low friction when membrane 1204 is coupled to object 1206, and relatively high friction to clamp membrane 1204 and object 1206 to base 1202. In some embodiments, the friction level at interface 1270 between membrane 1204 and base 1202 is adjustable using electrostatic charges, lubrication, specifics shapes of surfaces of membrane 1204 and / or base 1202, areal friction distribution, capillary clamping, mechanical flexures, locally confined gasses and / or liquids, surface roughness variations, and / or other techniques.

[0121] Fig. 13 provides another view of membrane 1204. As shown in Fig. 13, in some embodiments, membrane 1204 comprises a plurality of sub portions 1300 interconnected by flexible couplers 1302 and / or other components. The plurality of sub portions 1300 interconnected by the flexible couplers 1302 are configured to at least in part facilitate relative compliance of membrane 1204 compared to base 1202 (Fig. 12) and / or object 1206 (Fig. 12). The relative compliance of membrane 1204 causes membrane 1204 to conform to a topology of object 1206 (e.g., see the undulating surface of object 1206 in Fig. 12) when membrane 1204 is coupled to object 1206. In some embodiments, the flexible couplers 1302 comprise relatively thinner areas of membrane 1204 compared to relatively thicker areas which form the plurality of sub portions 1300, and / or other flexible couplers. In some embodiments, each of the plurality of sub portions 1300 comprises one or more burls 1304 configured to contact object 1206 (Fig. 12), with minimal lateral shear between each burl 1304 and object 1206 because of the relative compliance of membrane 1204, for example. In some embodiments, membrane 1204 comprises burls 1304, with intermediate areas (e.g., flexible couplers 1302 and / or other areas of sub portions 1300) comprising a relatively soft material compared to burls 1304. Burls 1304 may be similar to and / or the same as the burls shown in other figures and described above. In some embodiments, each of the plurality of sub portions 1300 has a square, rectangular, hexagonal (e.g., as shown in Fig. 13), octagonal, round, and / or other shape. Each sub portion 1300 may have any shape that allows membrane 1204 to function as described herein.

[0122] Other arrangements are contemplated. For example, in some embodiments, membrane 1204 may be formed by individual compliant sub portions (not connected to each other at all) are positioned on a holder and configured to receive and individually couple to object 1206.

[0123] Fig. 14 illustrates yet another clamping system 1400 (for a lithography apparatus). System 1400 may be similar to and / or the same as system 1200 shown in Fig. 12, and / or system 400 shown in Fig. 4. In this example, system 1400 is an electrostatic clamping system (with clamping and / or holding forces provided by oppositely charged components (e.g., see the + and - charge indicators in Fig. 14). System 1400 comprises a base 1402 (which may be similar to and / or the same as base 402 shown in Fig. 4 and / or base 1202 shown in Fig. 12), a membrane 1404 (which may be similar to and / or the same as membrane 404 shown in Fig. 4 and / or membrane 1204 shown in Fig. 12), and / or other components. Base 1402 may comprise a clamp 1408 (which may be similar to and / or the same as clamp 408 shown in Fig. 4 and / or clamp 1208 shown in Fig. 12) comprising one or more electrodes and / or other components configured to provide a holding force. The holding force is configured to removably hold an object 1406 (e.g., a reticle or mask, a substrate such as a semiconductor wafer, and / or other objects). The holding force may be an electrostatic force in this example. Membrane 1404 may comprise a coupler 1450 (which may be similar to and / or the same as coupler 450 shown in Fig. 4 and / or coupler 1250 shown in Fig. 12) configured to provide a coupling force to removably couple membrane 1404 to object 1406 and / or base 1402, and / or other components. In this example, coupler 1450 may comprise an electrode configured to provide an electrostatic coupling force, for example.

[0124] Fig. 14 illustrates clamping object 1406 in successive steps 1470, 1480, and 1490. Membrane 1404 is configured to be removably coupled to base 1402 and engage object 1406. Membrane 1404 is configured to first couple to object 1406 and conform to a shape of object 1406 (see steps 1470 to 1480), and then couple to base 1402 (see steps 1480 to 1490). In the example shown in Fig. 14, membrane 1404 again comprises a plurality of sub portions 1401 (which are similar to and / or the same as sub portions 1300 shown in Fig. 13) interconnected by flexible couplers 1403 (e.g., shown as miniature springs in Fig. 14, but which may be similar to and / or the same as flexible couplers 1302 shown in Fig.13) and / or other components. The plurality of sub portions 1401 interconnected by the flexible couplers 1403 are configured to at least in part facilitate relative compliance of membrane 1404 compared to base 1402 and / or object 1406. The relative compliance of membrane 1404 causes membrane 1404 to conform to a topology of object 1406 (e.g., see the curving surface of object 1406 in step 1470 of Fig.14) when membrane 1404 is coupled to object 1406. In some embodiments, each of the plurality of sub portions 1401 comprises one or more burls 1405 configured to contact object 1406, with minimal lateral shear between each burl 1405 and object 1406 because of the relative compliance of membrane 1404, for example. Burls 1405 may be similar to and / or the same as the burls shown in other figures and described above.

[0125] Membrane 1404 and base 1402 may be mechanically separate when membrane 1404 couples to object 1406. Mechanically separate may comprise not touching at all, deformable relative to each other, flexible relative to each other, and / or loosely connected to each other, for example. In some embodiments, membrane 1404 and base 1402 may be mechanically connected, while still allowing membrane 1404 to move independently, during clamping. In Fig. 14, this independent movementcapability is indicated by vertical springs 1411 (which may move up and down and / or tilt left or right in this illustration) and rollers 1413 (which may move left or right in this illustration). Vertical springs 1411 and / or rollers 1413 may represent the thicker / thinner, or softer / harder material described above, for example.

[0126] In some embodiments, the interface (e.g., interface 1270 shown in Fig. 12) between membrane 1404 and base 1402 (e.g., vertical springs 1411 and rollers 1413 in the example shown in Fig. 14) is relatively low friction 1420 at steps 1470 and / or 1480. A friction level at the interface between membrane 1404 and base 1402 is adjustable to provide the relatively low friction when membrane 1404 is coupled to object 1406, and relatively high friction 1430 to clamp membrane 1404 and object 1406 to base 1402 (at step 1490).

[0127] Fig. 15 illustrates a clamping method 1500. Method 1500 may be performed with an clamping system, a membrane, and / or other components, as described herein. The clamping system may be part of a lithography apparatus, a metrology apparatus, and / or other systems. In some embodiments, one or more operations of method 1500 are controlled by one or more processors and / or a computing system, as described below (see Fig. 16). The operations of method 1500 presented below are intended to be illustrative. In some embodiments, method 1500 may be accomplished with one or more additional operations not described, and / or without one or more of the operations discussed. Additionally, the order in which the operations of method 1500 are illustrated in Fig. 15 and described below is not intended to be limiting.

[0128] In some embodiments, one or more operations of method 1500 may be implemented in and / or controlled by one or more processing devices (e.g., a digital processor, an analog processor, a digital circuit designed to process information, an analog circuit designed to process information, a state machine, and / or other mechanisms for electronically processing information, as described with respect to Fig. 16 below). The one or more processing devices may include one or more devices executing some or all of the operations of method 1500 in response to instructions stored electronically on an electronic storage medium. The one or more processing devices may include one or more devices configured through hardware, firmware, and / or software to be specifically designed for execution of one or more of the operations of method 1500 (e.g., see discussion related to Fig. 16 below). For example, the one or more processing devices may run software configured to control energization of an electrode of an electrostatic clamping system.

[0129] At an operation 1502, a base is provided. The base may comprise one or more electrodes and / or other components. The one or more electrodes provide electrostatic force configured to removably hold an object (e.g., a reticle or mask, a substrate such as a semiconductor wafer, and / or other objects). In some embodiments, the base comprises a clamp configured to releasably clamp a membrane and the object. In some embodiments, the base comprises a chuck coupled to the clamp. The chuck is configured to hold the clamp, the membrane, and the object, and facilitate movement of the clamp, the membrane, and the object.

[0130] In some embodiments, the base comprises a contact surface with at least some portions coated with a dielectric material configured to contact a first surface (e.g., a base facing surface) of the membrane. The dielectric material is configured to act as an electrically insulating barrier between the one or more base electrodes and the surrounding environment. In some embodiments, the base comprises a contact surface comprising an exposed metal surface configured to contact the first surface, with the exposed metal surface comprising an electrode. The membrane may be configured with or without its own high voltage connection based on whether the base has the dielectric material or an exposed metal surface. In some embodiments, the contact surface comprises a reference surface profile, and the first surface of the membrane is configured based on the reference surface profile. In some embodiments, operation 1502 is performed by a base that is similar to and / or the same as base 402 shown in Fig. 4, and / or base 1202 shown in Fig. 12, and described above.

[0131] At an operation 1504, the membrane is provided. The membrane comprises the first surface, which is configured to contact the base; a second, opposite surface, for engaging the object; a coupler configured to provide a coupling force to removably couple the membrane to the base; and / or other components. The coupler may be passive, having no moving parts or electrically energized components. In some embodiments, the first surface comprises first burls configured to contact the base, with the first burls protruding from the first surface toward the base. In some embodiments, the base comprises the first burls, with the first burls protruding from the base toward and configured to contact the first surface. The second surface may comprise second burls for engaging the object, with the second burls protruding from the second surface. In some embodiments, the first burls and / or the second burls comprise flexible pillars configured for a van der Waals, Johnsen-Rahbek, and / or capillary adhesion interaction with the base and / or the object, and / or other components.

[0132] In some embodiments, the coupler comprises one or more electrode layers. Each electrode layer comprises one or more membrane electrodes configured such that the electrostatic force capacitively couples the membrane to the base and / or the object. In some embodiments, the one or more electrode layers comprise one electrode layer between the first surface and the second surface. In some embodiments, the one or more electrode layers comprise two electrode layers, with a first electrode layer located proximate to the first surface, and a second electrode layer located proximate to the second surface.

[0133] In some embodiments, the coupler comprises one or more magnets configured to provide the coupling force to removably couple the membrane to the base. In some embodiments, the coupler comprises one or more mechanical components configured to provide the coupling force to removably couple the membrane to the base.

[0134] In some embodiments, the membrane is permeable to cooling gas provided from the base. Operation 1504 may comprise providing the cooling gas at a first interface between the base and the membrane, and at a second interface between the membrane and the object. In some embodiments, the membrane comprises cooling gas channels configured to conduct the cooling gas from the first interfaceto the second interface. In some embodiments, the cooling gas comprises hydrogen, oxygen, nitrogen, air, and / or other cooling gases. In some embodiments, operation 1504 comprises providing one or more fluid (e.g., liquid or gas) cooling channels in the base to cool the base.

[0135] In some embodiments, operation 1504 may comprise manufacturing the membrane with one or more of the features described above.

[0136] In some embodiments, operation 1504 is performed by a membrane that is similar to and / or the same as membrane 404 shown in Fig. 4, and / or membrane 1204 shown in Fig. 12, and described above.

[0137] At an operation 1506, the membrane is removably coupled to the base and / or the object, to engage the object. In some embodiments, during operation 1506, the one or more base electrodes are configured to be energized and de-energized to provide or remove an electrostatic and / or other holding or coupling forces (to removably couple the membrane and / or engage the object). The electrostatic force may be coulombic or Johsen-Rahbek based, for example. In some embodiments, operation 1506 comprises progressively energizing the one or more base electrodes such that contact between the membrane and the base propagates from an initially energized contact location progressively across the membrane. In some embodiments, the membrane comprises a physical or virtual ground connection configured to enhance removable coupling of the membrane to the base and / or the object. In some embodiments, the one or more base electrodes are configured to provide the electrostatic force to independently control clamping forces on the membrane and / or the object by selective application of voltage to the one or more base electrodes. In some embodiments, the holding force and / or the coupling force is an electrostatic force (e.g., as described above), a mechanical force, a vacuum force, a magnetic force, a chemical force, and / or other forces. In some embodiments, operation 1506 is performed by a membrane that is similar to and / or the same as membrane 404 and / or membrane 1204, and a base that is similar to and / or the same as base 402 and / or base 1202, shown in Fig. 4 and Fig. 12, and described above.

[0138] In some embodiments, method 1500 comprises moving the membrane with a tool handler including a reticle handler turret gripper and a reticle handler robot gripper (of the lithography apparatus). The reticle handler robot gripper is configured to move the membrane and / or the object from a load port of a lithography apparatus, and the reticle handler turret gripper is configured to position the membrane for contacting the base, and / or the object for contacting the membrane.

[0139] In some embodiments, the tool handler comprises a membrane installation tool configured for contacting the membrane to the base. The membrane installation tool comprises a surface and / or end stops configured to support the membrane in a contacting position. In some embodiments, the membrane installation tool comprises one or more magnets configured to attract the membrane against the surface during installation and / or removal. In some embodiments, the membrane installation tool comprises a contour configured to shape the surface such that a center of the membrane first contacts the base during installation. In some embodiments, the membrane installation tool comprises one or more installation electrodes configured to provide a second electrostatic force configured to removablyhold the membrane during installation and / or removal.

[0140] The membrane may be relatively thin and compliant compared to the base and / or the object. As part of method 1500, the membrane may be configured to first couple to the object and conform to a shape of the object, and then couple to the base. In this way, the membrane may form a known tunable interface (see Fig. 12) configured for coupling the object to the base.

[0141] In some embodiments, the membrane and the base are mechanically separate when the membrane couples to the object at operation 1506. Mechanically separate comprises not contacting each other at all, deformable relative to each other, flexible relative to each other, and / or loosely connected to each other, for example. However, in some embodiments, the membrane and the base are mechanically connected, while still allowing the membrane to move independently, during clamping (operation 1506).

[0142] In some embodiments, an interface between the membrane and the base is relatively low friction compared to another interface between the membrane and the object, when the membrane is coupled to the object at operation 1506. In some embodiments, a friction level at the interface between the membrane and the base is adjustable to provide the relatively low friction when the membrane is coupled to the object, and relatively high friction to clamp the membrane and the object to the base. The friction level at the interface between the membrane and the base may be adjustable using electrostatic charges, lubrication, specifics shapes of surfaces of the membrane and / or the base, areal friction distribution, capillary clamping, mechanical flexures, locally confined gasses and / or liquids, surface roughness, and / or other techniques.

[0143] In some embodiments, the membrane comprises a plurality of sub portions interconnected by flexible couplers (as described above). The plurality of sub portions interconnected by the flexible couplers is configured to at least in part facilitate relative compliance of the membrane compared to the base and / or the object. The relative compliance of the membrane causes the membrane to conform to a topology of the object when the membrane is coupled to the object (e.g., at operation 1506). In some embodiments, the flexible couplers comprise relatively thinner areas of the membrane compared to relatively thicker areas which form the plurality of sub portions. In some embodiments, each of the plurality of sub portions comprises one or more burls configured to contact the object, with minimal lateral shear between each burl and the object because of the relative compliance of the membrane. For example, the membrane may comprise the burls, with intermediate areas comprising a relatively soft material compared to the burls. In some embodiments, each of the plurality of sub portions has a square, rectangular, hexagonal (e.g., see Fig. 13), octagonal, round, and / or other shapes.

[0144] In some embodiments, the membrane is configured to facilitate relatively low friction during object loading, to prevent in-plane deformations; and facilitate relatively high friction during semiconductor lithography exposure, to prevent the object from slipping during acceleration and local heating. In addition, the thermal conductivity of the membrane may be relatively low compared to the base and / or the object.

[0145] Fig. 16 is a block diagram that illustrates a computer system 1600 that can assist in implementing the methods, flows, or the system(s) disclosed herein. Computer system 1600 may be included in and / or electronically coupled to lithography apparatus LA described above (Fig. 1, Fig. 3 A, etc.). Computer system 1600 includes a bus 1602 or other communication mechanism for communicating information, and a processor 1604 (or multiple processors 1604, 1605, etc.) coupled with bus 1602 for processing information. Computer system 1600 also includes a main memory 1606, such as a random access memory (RAM) or other dynamic storage device, coupled to bus 1602 for storing information and instructions to be executed by processor 1604. Main memory 1606 also may be used for storing temporary variables or other intermediate information during execution of instructions to be executed by processor 1604. Computer system 1600 further includes a read only memory (ROM) 1608 or other static storage device coupled to bus 1602 for storing static information and instructions for processor 1604. A storage device 1610, such as a magnetic disk or optical disk, is provided and coupled to bus 1602 for storing information and instructions.

[0146] Computer system 1600 may be coupled via bus 1602 to a display 1612, such as a flat panel or touch panel display for displaying information to a computer user. An input device 1614, including alphanumeric and other keys, is coupled to bus 1602 for communicating information and command selections to processor 1604. Another type of user input device is cursor control 1616, such as a mouse, a trackball, or cursor direction keys for communicating direction information and command selections to processor 1304 and for controlling cursor movement on display 1312. This input device typically has two degrees of freedom in two axes, a first axis (e.g., x) and a second axis (e.g., y), that allows the device to specify positions in a plane. A touch panel (screen) display may also be used as an input device.

[0147] According to one embodiment, portions of one or more flows and / or methods described herein may be performed by computer system 1600 in response to processor 1604 executing one or more sequences of one or more instructions contained in main memory 1606. Such instructions may be read into main memory 1606 from another computer-readable medium, such as storage device 1610. Execution of the sequences of instructions contained in main memory 1606 causes processor 1604 to perform the flows and / or process steps described herein. One or more processors in a multi-processing arrangement may also be employed to execute the sequences of instructions contained in main memory 1606. In an alternative embodiment, hard-wired circuitry may be used in place of or in combination with software instructions. Thus, the description herein is not limited to any specific combination of hardware circuitry and software.

[0148] The term “computer-readable medium” or “machine readable medium” refers to any medium that participates in providing instructions to processor 1604 for execution. Such a medium may take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media include, for example, optical or magnetic disks, such as storage device 1610. Volatile media include dynamic memory, such as main memory 1606. Transmission media includecoaxial cables, copper wire and fiber optics, including the wires that comprise bus 1602. Transmission media can also take the form of acoustic or light waves, such as those generated during radio frequency (RF) and infrared (IR) data communications. Common forms of computer-readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a CD- ROM, DVD, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave as described hereinafter, or any other medium from which a computer can read.

[0149] Various forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to processor 1604 for execution. For example, the instructions may initially be borne on a magnetic disk of a remote computer. The remote computer can load the instructions into its dynamic memory and send the instructions over a network. Computer system 1600 can receive the data. Bus 1602 carries the data to main memory 1606, from which processor 1604 retrieves and executes the instructions. The instructions received by main memory 1606 may optionally be stored on storage device 1610 either before or after execution by processor 1604.

[0150] Computer system 1600 may also include a communication interface 1618 coupled to bus 1602. Communication interface 1618 provides a two-way data communication coupling to a network link 1620 that is connected to a local network 1622. For example, communication interface 1618 may be an integrated services digital network (ISDN) card or a modem to provide a data communication connection to a corresponding type of telephone line. As another example, communication interface 1618 may be a local area network (LAN) card to provide a data communication connection to a compatible LAN. Wireless links may also be implemented. In any such implementation, communication interface 1618 sends and receives electrical, electromagnetic, or optical signals that carry digital data streams representing various types of information.

[0151] Network link 1620 typically provides data communication through one or more networks to other data devices. For example, network link 1620 may provide a connection through local network 1622 to a host computer 1624 or to data equipment operated by an Internet Service Provider (ISP) 1626. ISP 1626 in turn provides data communication services through the worldwide packet data communication network, now commonly referred to as the “Internet” 1628. Local network 1622 and Internet 1628 both use electrical, electromagnetic, or optical signals that carry digital data streams. The signals through the various networks and the signals on network link 1620 and through communication interface 1618, which carry the digital data to and from computer system 1600, are exemplary forms of carrier waves transporting the information.

[0152] Computer system 1600 can send messages and receive data, including program code, through the network(s), network link 1620, and communication interface 1618. In the Internet example, a server 1630 might transmit a requested code for an application program through Internet 1628, ISP 1626, local network 1622 and communication interface 1618. One such downloaded application may provide all or part of a method described herein, for example. The received code may be executed by processor1604 as it is received, and / or stored in storage device 1610, or other non-volatile storage for later execution. In this manner, computer system 1600 may obtain application code in the form of a carrier wave.

[0153] Various embodiments of the present systems and methods are disclosed in the subsequent list of numbered clauses:1. A clamping system for a lithography apparatus, comprising: a base configured to provide a holding force configured to removably hold an object; and a membrane configured to be removably coupled to the base and engage the object, the membrane comprising: a first surface configured to contact the base; a second, opposite surface, for engaging the object; and a coupler configured to provide a coupling force to removably couple the membrane to the object and / or the base.2. The system of clause 1, wherein the base comprises a clamp configured to releasably clamp the membrane and the object.3. The system of any of the previous clauses, wherein the base further comprises a chuck coupled to the clamp, the chuck configured to hold the clamp, the membrane, and the object, and facilitate movement of the clamp, the membrane, and the object.4. The system of any of the previous clauses wherein the object comprises a reticle or a wafer, and the clamping system is part of a lithography apparatus used in semiconductor manufacturing.5. The system of any of the previous clauses, wherein the base comprises one or more base electrodes configured to provide electrostatic force configured to removably hold the object and / or the membrane; and wherein the one or more base electrodes are configured to be energized and de-energized to provide or remove the electrostatic force.6. The system of any of the previous clauses, wherein the one or more base electrodes are configured to be progressively energized such that contact between the membrane and the base propagates from an initially energized contact location progressively across the membrane.7. The system of any of the previous clauses, wherein the coupler is passive, having no moving parts or electrically energized components.8. The system of any of the previous clauses, wherein the coupler comprises one or more electrode layers, each electrode layer comprising one or more membrane electrodes configured such that electrostatic force capacitively couples the membrane to the base and / or the object.9. The system of any of the previous clauses, wherein the one or more electrode layers comprise one electrode layer between the first surface and the second surface.10. The system of any of the previous clauses, wherein the one or more electrode layers comprise two electrode layers, with a first electrode layer located proximate to the first surface, and a second electrode layer located proximate to the second surface.11. The system of any of the previous clauses, wherein the coupler comprises one or more magnets configured to provide the coupling force to removably couple the membrane to the base.12. The system of any of the previous clauses, wherein the coupler comprises one or more mechanicaland / or vacuum components configured to provide the coupling force to removably couple the membrane to the base.13. The system of any of the previous clauses, wherein the membrane is permeable to cooling gas provided from the base such that the cooling gas is provided at a first interface between the base and the membrane, and at a second interface between the membrane and the object.14. The system of any of the previous clauses, wherein the membrane further comprises cooling gas channels configured to conduct the cooling gas from the first interface to the second interface.15. The system of any of the previous clauses, wherein the cooling gas comprises hydrogen, oxygen, nitrogen, and / or air.16. The system of any of the previous clauses, wherein the base comprises one or more fluid cooling channels configured to cool the base.17. The system of any of the previous clauses, wherein the base comprises a contact surface with at least one portion coated with a dielectric material configured to contact the first surface, wherein the dielectric material is configured to act as an electrically insulating barrier between one or more base electrodes and a surrounding environment.18. The system of any of the previous clauses, wherein the dielectric material comprises diamond, Si3N4, A12O3, SiO2, Ta2O5, TiO2, HfO2, and / or ZrO2.19. The system of any of the previous clauses, wherein the base comprises a contact surface comprising an exposed metal surface configured to contact the first surface, with the exposed metal surface comprising an electrode.20. The system of any of the previous clauses, wherein the membrane is configured with its own high voltage connection.21. The system of any of the previous clauses, wherein the contact surface comprises a reference surface profile, and wherein the first surface of the membrane is configured based on the reference surface profile.22. The system of any of the previous clauses, wherein the base comprises one or more base electrodes configured to provide electrostatic force configured to removably hold the object; and wherein the one or more base electrodes are configured to provide the electrostatic force to independently control clamping forces on the membrane and / or the object by selective application of voltage to the one or more base electrodes.23. The system of any of the previous clauses, wherein the membrane further comprises a physical or virtual ground connection configured to enhance removable coupling of the membrane to the base and / or the object.24. The system of any of the previous clauses, further comprising a tool handler including a reticle handler turret gripper and a reticle handler robot gripper, wherein the reticle handler robot gripper is configured to move the membrane and / or the object from a load port of a lithography apparatus, andwherein the reticle handler turret gripper is configured to position the membrane for contacting the base, and / or the object.25. The system of any of the previous clauses, wherein the tool handler comprises a membrane installation tool configured for contacting the membrane to the object and / or the base, wherein the membrane installation tool comprises a surface and / or end stops configured to support the membrane in a contacting position.26. The system of any of the previous clauses, wherein the tool handler comprises a membrane installation tool configured for contacting the membrane to the object and / or the base, wherein the membrane installation tool comprises one or more magnets configured to attract the membrane against the surface during installation and / or removal.27. The system of any of the previous clauses, wherein the tool handler comprises a membrane installation tool configured for contacting the membrane to the object and / or the base, wherein the membrane installation tool comprises a contour configured to shape the surface such that a center of the membrane first contacts the object and / or the base during installation.28. The system of any of the previous clauses, wherein the membrane installation tool comprises one or more installation electrodes configured to provide electrostatic force configured to removably hold the membrane during installation and / or removal.29. The system of any of the previous clauses, wherein the first surface comprises first burls configured to contact the base, the first burls protruding from the first surface toward the base; or wherein the base comprises the first burls, with the first burls protruding from the base toward and configured to contact the first surface.30. The system of any of the previous clauses, wherein the second surface comprises second burls for engaging the object, the second burls protruding from the second surface.31. The system of any of the previous clauses, wherein the first burls and / or second burls comprise flexible pillars configured for a van der Waals, Johnsen-Rahbek, and / or capillary adhesion interaction with the base and / or the object.32. The system of any of the previous clauses, wherein the membrane is relatively thin and compliant compared to the base and / or the object.33. The system of any of the previous clauses, wherein the membrane is configured to first couple to the object and conform to a shape of the object, and then couple to the base.34. The system of any of the previous clauses, wherein the membrane forms a known tunable interface configured for coupling the object to the base.35. The system of any of the previous clauses, wherein the membrane and the base are mechanically separate when the membrane couples to the object.36. The system of any of the previous clauses, wherein mechanically separate comprises deformable relative to each other, flexible relative to each other, and / or loosely connected to each other.37. The system of any of the previous clauses, wherein the membrane and the base are mechanically connected, while still allowing the membrane to move independently, during clamping.38. The system of any of the previous clauses, wherein an interface between the membrane and the base is relatively low friction compared to another interface between the membrane and the object, when the membrane is coupled to the object.39. The system of any of the previous clauses, wherein a friction level at the interface between the membrane and the base is adjustable to provide the relatively low friction when the membrane is coupled to the object, and relatively high friction to clamp the membrane and the object to the base.40. The system of any of the previous clauses, wherein the friction level at the interface between the membrane and the base is adjustable using electrostatic charges, lubrication, specifics shapes of surfaces of the membrane and / or the base, areal friction distribution, capillary clamping, mechanical flexures, locally confined gasses and / or liquids, and / or surface roughness.41. The system of any of the previous clauses, wherein the membrane comprises a plurality of sub portions interconnected by flexible couplers, the plurality of sub portions interconnected by the flexible couplers configured to at least in part facilitate relative compliance of the membrane compared to the base and / or the object.42. The system of any of the previous clauses, wherein the relative compliance of the membrane causes the membrane to conform to a topology of the object when the membrane is coupled to the object.43. The system of any of the previous clauses, wherein the flexible couplers comprise relatively thinner areas of the membrane compared to relatively thicker areas which form the plurality of sub portions.44. The system of any of the previous clauses, wherein each of the plurality of sub portions comprises one or more burls configured to contact the object, with minimal lateral shear between each burl and the object because of the relative compliance of the membrane.45. The system of any of the previous clauses, wherein each of the plurality of sub portions has a square, rectangular, hexagonal, octagonal, or round shape.46. The system of any of the previous clauses, wherein the holding force and / or the coupling force is an electrostatic force, a mechanical force, a vacuum force, a magnetic force, and / or a chemical force.47. The system of any of the previous clauses, wherein the electrostatic force is coulombic or Johsen- Rahbek based.48. The system of any of the previous clauses, wherein the membrane is configured to facilitate relatively low friction during object loading, to prevent in-plane deformations; and facilitate relatively high friction during semiconductor lithography exposure, to prevent the object from slipping during acceleration and local heating.49. The system of any of the previous clauses, wherein a thermal conductivity of the membrane is relatively low compared to the base and / or the object.50. The system of any of the previous clauses, wherein the membrane comprises burls, with intermediate areas comprising a relatively soft material compared to the burls.51. A membrane configured to be removably coupled to a base and / or an object, the membrane configured to be positioned between the base and the object, the membrane comprising: a first surface configured to contact the base, a second, opposite surface, configured to contact the object; and a coupler configured to provide a coupling force to removably couple the membrane to the base and / or the object.52. The membrane of any of the previous clauses, wherein: the base comprises: one or more base electrodes configured to provide electrostatic force configured to removably hold the object and / or the membrane, the one or more base electrodes configured to be energized and de-energized to provide or remove the electrostatic force; a clamp configured to releasably clamp the membrane and / or the object; and a chuck coupled to the clamp, the chuck configured to hold the clamp, the membrane, and the object, and facilitate movement of the clamp, the membrane, and the object; and wherein: the object comprises a reticle or a wafer, and the reticle or the wafer is configured to be used in a lithography apparatus for semiconductor manufacturing.53. The membrane of any of the previous clauses, wherein the coupler is passive, having no moving parts or electrically energized components.54. The membrane of any of the previous clauses, wherein the coupler comprises one or more electrode layers, each electrode layer comprising one or more membrane electrodes configured such that an electrostatic force capacitively couples the membrane to the base and / or the object.55. The membrane of any of the previous clauses, wherein the one or more electrode layers comprise one electrode layer between the first surface and the second surface.56. The membrane of any of the previous clauses, wherein the one or more electrode layers comprise two electrode layers, with a first electrode layer located proximate to the first surface, and a second electrode layer located proximate to the second surface.57. The membrane of any of the previous clauses, wherein the coupler comprises one or more magnets configured to provide the coupling force to removably couple the membrane to the base.58. The membrane of any of the previous clauses, wherein the coupler comprises one or more mechanical and / or vacuum components configured to provide the coupling force to removably couple the membrane to the base.59. The membrane of any of the previous clauses, wherein the membrane is permeable to cooling gas provided from the base such that the cooling gas is provided at a first interface between the base and the membrane, and at a second interface between the membrane and the object.60. The membrane of any of the previous clauses, wherein the membrane further comprises cooling gas channels configured to conduct the cooling gas from the first interface to the second interface.61. The membrane of any of the previous clauses, wherein the cooling gas comprises hydrogen, oxygen, nitrogen, and / or air.62. The membrane of any of the previous clauses, wherein the base comprises a contact surface with at least some portions coated with a dielectric material configured to contact the first surface, wherein thedielectric material is configured to act as an electrically insulating barrier between one or more base electrodes and a surrounding environment.63. The membrane of any of the previous clauses, wherein the dielectric material comprises diamond, Si3N4, A12O3, SiO2, Ta2O5, TiO2, HfO2, and / or ZrO2.64. The membrane of any of the previous clauses, wherein the base comprises a contact surface comprising an exposed metal surface configured to contact the first surface, with the exposed metal surface comprising an electrode.65. The membrane of any of the previous clauses, wherein the membrane is configured with or without its own high voltage connection based on whether the base has the dielectric material or an exposed metal surface.66. The membrane of any of the previous clauses, wherein the contact surface comprises a reference surface profile, and wherein the first surface of the membrane is configured based on the reference surface profile.67. The membrane of any of the previous clauses, wherein the membrane further comprises a physical or virtual ground connection configured to enhance removable coupling of the membrane to the base and / or the object.68. The membrane of any of the previous clauses, wherein the first surface comprises first burls configured to contact the base, the first burls protruding from the first surface toward the base.69. The membrane of any of the previous clauses, wherein the base comprises first burls, with the first burls protruding from the base toward and configured to contact the first surface.70. The membrane of any of the previous clauses, wherein the second surface comprises second burls for engaging the object, the second burls protruding from the second surface.71. The membrane of any of the previous clauses, wherein the first burls and / or the second burls comprise flexible pillars configured for a van der Waals, Johnsen-Rahbek, and / or capillary adhesion interaction with the base and / or the object.72. The membrane of any of the previous clauses, wherein the membrane is relatively thin and compliant compared to the base and / or the object.73. The membrane of any of the previous clauses, wherein the membrane is configured to first couple to the object and conform to a shape of the object, and then couple to the base.74. The membrane of any of the previous clauses, wherein the membrane forms a known tunable interface configured for coupling the object to the base.75. The membrane of any of the previous clauses, wherein the membrane and the base are mechanically separate when the membrane couples to the object.76. The membrane of any of the previous clauses, wherein mechanically separate comprises deformable relative to each other, flexible relative to each other, and / or loosely connected to each other.77. The membrane of any of the previous clauses, wherein the membrane and the base are mechanically connected, while still allowing the membrane to move independently, during clamping.78. The membrane of any of the previous clauses, wherein an interface between the membrane and the base is relatively low friction compared to another interface between the membrane and the object, when the membrane is coupled to the object.79. The membrane of any of the previous clauses, wherein a friction level at the interface between the membrane and the base is adjustable to provide the relatively low friction when the membrane is coupled to the object, and relatively high friction to clamp the membrane and the object to the base.80. The membrane of any of the previous clauses, wherein the friction level at the interface between the membrane and the base is adjustable using electrostatic charges, lubrication, specifics shapes of surfaces of the membrane and / or the base, areal friction distribution, capillary clamping, mechanical flexures, locally confined gasses and / or liquids, and / or surface roughness.81. The membrane of any of the previous clauses, wherein the membrane comprises a plurality of sub portions interconnected by flexible couplers, the plurality of sub portions interconnected by the flexible couplers configured to at least in part facilitate relative compliance of the membrane compared to the base and / or the object.82. The membrane of any of the previous clauses, wherein the relative compliance of the membrane causes the membrane to conform to a topology of the object when the membrane is coupled to the object.83. The membrane of any of the previous clauses, wherein the flexible couplers comprise relatively thinner areas of the membrane compared to relatively thicker areas which form the plurality of sub portions.84. The membrane of any of the previous clauses, wherein each of the plurality of sub portions comprises one or more burls configured to contact the object, with minimal lateral shear between each burl and the object because of the relative compliance of the membrane.85. The membrane of any of the previous clauses, wherein each of the plurality of sub portions has a square, rectangular, hexagonal, octagonal, or round shape.86. The membrane of any of the previous clauses, wherein the holding force and / or the coupling force is an electrostatic force, a mechanical force, a vacuum force, a magnetic force, and / or a chemical force.87. The membrane of any of the previous clauses, wherein the electrostatic force is coulombic or Johsen-Rahbek based.88. The membrane of any of the previous clauses, wherein the membrane is configured to facilitate relatively low friction during object loading, to prevent in-plane deformations; and facilitate relatively high friction during semiconductor lithography exposure, to prevent the object from slipping during acceleration and local heating.89. The membrane of any of the previous clauses, wherein a thermal conductivity of the membrane is relatively low compared to the base and / or the object.90. The membrane of any of the previous clauses, wherein the membrane comprises burls, with intermediate areas comprising a relatively soft material compared to the burls.91. A clamping method for a lithography apparatus, comprising: providing, with a base of the lithography apparatus, a holding force configured to removably hold an object; and removably coupling a membrane to the base, and engaging the object with the membrane, the membrane comprising: a first surface configured to contact the base; a second, opposite surface, for engaging the object; and a coupler configured to provide a coupling force to removably couple the membrane to the object and / or the base.92. The method of clause 91, wherein the base comprises a clamp configured to releasably clamp the membrane and the object.93. The method of any of the previous clauses, wherein the base further comprises a chuck coupled to the clamp, the chuck configured to hold the clamp, the membrane, and the object, and facilitate movement of the clamp, the membrane, and the object.94. The method of any of the previous clauses, wherein the object comprises a reticle or a wafer, and the clamping system is part of a lithography apparatus used in semiconductor manufacturing.95. The method of any of the previous clauses, wherein the base comprises one or more base electrodes configured to provide electrostatic force configured to removably hold the object and / or the membrane; and wherein the one or more base electrodes are configured to be energized and de-energized to provide or remove the electrostatic force.96. The method of any of the previous clauses, wherein the one or more base electrodes are configured to be progressively energized such that contact between the membrane and the base propagates from an initially energized contact location progressively across the membrane.97. The method of any of the previous clauses, wherein the coupler is passive, having no moving parts or electrically energized components.98. The method of any of the previous clauses, wherein the coupler comprises one or more electrode layers, each electrode layer comprising one or more membrane electrodes configured such that electrostatic force capacitively couples the membrane to the base and / or the object.99. The method of any of the previous clauses, wherein the one or more electrode layers comprise one electrode layer between the first surface and the second surface.100. The method of any of the previous clauses, wherein the one or more electrode layers comprise two electrode layers, with a first electrode layer located proximate to the first surface, and a second electrode layer located proximate to the second surface.101. The method of any of the previous clauses, wherein the coupler comprises one or more magnets configured to provide the coupling force to removably couple the membrane to the base.102. The method of any of the previous clauses, wherein the coupler comprises one or more mechanical and / or vacuum components configured to provide the coupling force to removably couple the membrane to the base.103. The method of any of the previous clauses, wherein the membrane is permeable to cooling gas provided from the base such that the cooling gas is provided at a first interface between the base and the membrane, and at a second interface between the membrane and the object.104. The method of any of the previous clauses, wherein the membrane further comprises cooling gas channels configured to conduct the cooling gas from the first interface to the second interface.105. The method of any of the previous clauses, wherein the cooling gas comprises hydrogen, oxygen, nitrogen, and / or air.106. The method of any of the previous clauses, wherein the base comprises one or more fluid cooling channels configured to cool the base.107. The method of any of the previous clauses, wherein the base comprises a contact surface with at least one portion coated with a dielectric material configured to contact the first surface, wherein the dielectric material is configured to act as an electrically insulating barrier between one or more base electrodes and a surrounding environment.108. The method of any of the previous clauses, wherein the dielectric material comprises diamond, Si3N4, A12O3, SiO2, Ta2O5, TiO2, HfO2, and / or ZrO2.109. The method of any of the previous clauses, wherein the base comprises a contact surface comprising an exposed metal surface configured to contact the first surface, with the exposed metal surface comprising an electrode.110. The method of any of the previous clauses, wherein the membrane is configured with its own high voltage connection.111. The method of any of the previous clauses, wherein the contact surface comprises a reference surface profile, and wherein the first surface of the membrane is configured based on the reference surface profile.112. The method of any of the previous clauses, wherein the base comprises one or more base electrodes configured to provide electrostatic force configured to removably hold the object; and wherein the one or more base electrodes are configured to provide the electrostatic force to independently control clamping forces on the membrane and / or the object by selective application of voltage to the one or more base electrodes.113. The method of any of the previous clauses, wherein the membrane further comprises a physical or virtual ground connection configured to enhance removable coupling of the membrane to the base and / or the object.114. The method of any of the previous clauses, further comprising moving, with a tool handler including a reticle handler turret gripper and a reticle handler robot gripper, the membrane and / or the object from a load port of a lithography apparatus, and wherein the reticle handler turret gripper is configured to position the membrane for contacting the base, and / or the object.115. The method of any of the previous clauses, wherein the tool handler comprises a membrane installation tool configured for contacting the membrane to the object and / or the base, wherein the membrane installation tool comprises a surface and / or end stops configured to support the membrane in a contacting position.116. The method of any of the previous clauses, wherein the tool handler comprises a membrane installation tool configured for contacting the membrane to the object and / or the base, wherein the membrane installation tool comprises one or more magnets configured to attract the membrane against the surface during installation and / or removal.117. The method of any of the previous clauses, wherein the tool handler comprises a membrane installation tool configured for contacting the membrane to the object and / or the base, wherein the membrane installation tool comprises a contour configured to shape the surface such that a center of the membrane first contacts the object and / or the base during installation.118. The method of any of the previous clauses, wherein the membrane installation tool comprises one or more installation electrodes configured to provide electrostatic force configured to removably hold the membrane during installation and / or removal.119. The method of any of the previous clauses, wherein the first surface comprises first burls configured to contact the base, the first burls protruding from the first surface toward the base; or wherein the base comprises the first burls, with the first burls protruding from the base toward and configured to contact the first surface.120. The method of any of the previous clauses, wherein the second surface comprises second burls for engaging the object, the second burls protruding from the second surface.121. The method of any of the previous clauses, wherein the first burls and / or second burls comprise flexible pillars configured for a van der Waals, Johnsen-Rahbek, and / or capillary adhesion interaction with the base and / or the object.122. The method of any of the previous clauses, wherein the membrane is relatively thin and compliant compared to the base and / or the object.123. The method of any of the previous clauses, wherein the membrane is configured to first couple to the object and conform to a shape of the object, and then couple to the base.124. The method of any of the previous clauses, wherein the membrane forms a known tunable interface configured for coupling the object to the base.125. The method of any of the previous clauses, wherein the membrane and the base are mechanically separate when the membrane couples to the object.126. The method of any of the previous clauses, wherein mechanically separate comprises deformable relative to each other, flexible relative to each other, and / or loosely connected to each other.127. The method of any of the previous clauses, wherein the membrane and the base are mechanically connected, while still allowing the membrane to move independently, during clamping.128. The method of any of the previous clauses, wherein an interface between the membrane and the base is relatively low friction compared to another interface between the membrane and the object, when the membrane is coupled to the object.129. The method of any of the previous clauses, wherein a friction level at the interface between the membrane and the base is adjustable to provide the relatively low friction when the membrane is coupled to the object, and relatively high friction to clamp the membrane and the object to the base.130. The method of any of the previous clauses, wherein the friction level at the interface between the membrane and the base is adjustable using electrostatic charges, lubrication, specifics shapes of surfaces of the membrane and / or the base, areal friction distribution, capillary clamping, mechanical flexures, locally confined gasses and / or liquids, and / or surface roughness.131. The method of any of the previous clauses, wherein the membrane comprises a plurality of sub portions interconnected by flexible couplers, the plurality of sub portions interconnected by the flexible couplers configured to at least in part facilitate relative compliance of the membrane compared to the base and / or the object.132. The method of any of the previous clauses, wherein the relative compliance of the membrane causes the membrane to conform to a topology of the object when the membrane is coupled to the object.133. The method of any of the previous clauses, wherein the flexible couplers comprise relatively thinner areas of the membrane compared to relatively thicker areas which form the plurality of sub portions.134. The method of any of the previous clauses, wherein each of the plurality of sub portions comprises one or more burls configured to contact the object, with minimal lateral shear between each burl and the object because of the relative compliance of the membrane.135. The method of any of the previous clauses, wherein each of the plurality of sub portions has a square, rectangular, hexagonal, octagonal, or round shape.136. The method of any of the previous clauses, wherein the holding force and / or the coupling force is an electrostatic force, a mechanical force, a vacuum force, a magnetic force, and / or a chemical force.137. The method of any of the previous clauses, wherein the electrostatic force is coulombic or Johsen- Rahbek based.138. The method of any of the previous clauses, wherein the membrane is configured to facilitate relatively low friction during object loading, to prevent in-plane deformations; and facilitate relatively high friction during semiconductor lithography exposure, to prevent the object from slipping during acceleration and local heating.139. The method of any of the previous clauses, wherein a thermal conductivity of the membrane is relatively low compared to the base and / or the object.140. The method of any of the previous clauses, wherein the membrane comprises burls, with intermediate areas comprising a relatively soft material compared to the burls.141. A method for removably coupling a membrane to a base and / or an object, the membrane configured to be positioned between the base and the object, the method comprising: contacting the base with a first surface of the membrane, contacting the object with a second, opposite surface, of themembrane; and providing, with a coupler, coupling force to removably couple the membrane to the base and / or the object.142. The method of any of the previous clauses, wherein: the base comprises: one or more base electrodes configured to provide electrostatic force configured to removably hold the object and / or the membrane, the one or more base electrodes configured to be energized and de-energized to provide or remove the electrostatic force; a clamp configured to releasably clamp the membrane and / or the object; and a chuck coupled to the clamp, the chuck configured to hold the clamp, the membrane, and the object, and facilitate movement of the clamp, the membrane, and the object; and wherein: the object comprises a reticle or a wafer, and the reticle or the wafer is configured to be used in a lithography apparatus for semiconductor manufacturing.143. The method of any of the previous clauses, wherein the coupler is passive, having no moving parts or electrically energized components.144. The method of any of the previous clauses, wherein the coupler comprises one or more electrode layers, each electrode layer comprising one or more membrane electrodes configured such that an electrostatic force capacitively couples the membrane to the base and / or the object.145. The method of any of the previous clauses, wherein the one or more electrode layers comprise one electrode layer between the first surface and the second surface.146. The method of any of the previous clauses, wherein the one or more electrode layers comprise two electrode layers, with a first electrode layer located proximate to the first surface, and a second electrode layer located proximate to the second surface.147. The method of any of the previous clauses, wherein the coupler comprises one or more magnets configured to provide the coupling force to removably couple the membrane to the base.148. The method of any of the previous clauses, wherein the coupler comprises one or more mechanical and / or vacuum components configured to provide the coupling force to removably couple the membrane to the base.149. The method of any of the previous clauses, wherein the membrane is permeable to cooling gas provided from the base such that the cooling gas is provided at a first interface between the base and the membrane, and at a second interface between the membrane and the object.150. The method of any of the previous clauses, wherein the membrane further comprises cooling gas channels configured to conduct the cooling gas from the first interface to the second interface.151. The method of any of the previous clauses, wherein the cooling gas comprises hydrogen, oxygen, nitrogen, and / or air.152. The method of any of the previous clauses, wherein the base comprises a contact surface with at least some portions coated with a dielectric material configured to contact the first surface, wherein the dielectric material is configured to act as an electrically insulating barrier between one or more base electrodes and a surrounding environment.153. The method of any of the previous clauses, wherein the dielectric material comprises diamond, Si3N4, A12O3, SiO2, Ta2O5, TiO2, HfO2, and / or ZrO2.154. The method of any of the previous clauses, wherein the base comprises a contact surface comprising an exposed metal surface configured to contact the first surface, with the exposed metal surface comprising an electrode.155. The method of any of the previous clauses, wherein the membrane is configured with or without its own high voltage connection based on whether the base has the dielectric material or an exposed metal surface.156. The method of any of the previous clauses, wherein the contact surface comprises a reference surface profile, and wherein the first surface of the membrane is configured based on the reference surface profile.157. The method of any of the previous clauses, wherein the membrane further comprises a physical or virtual ground connection configured to enhance removable coupling of the membrane to the base and / or the object.158. The method of any of the previous clauses, wherein the first surface comprises first burls configured to contact the base, the first burls protruding from the first surface toward the base.159. The method of any of the previous clauses, wherein the base comprises first burls, with the first burls protruding from the base toward and configured to contact the first surface.160. The method of any of the previous clauses, wherein the second surface comprises second burls for engaging the object, the second burls protruding from the second surface.161. The method of any of the previous clauses, wherein the first burls and / or the second burls comprise flexible pillars configured for a van der Waals, Johnsen-Rahbek, and / or capillary adhesion interaction with the base and / or the object.162. The method of any of the previous clauses, wherein the membrane is relatively thin and compliant compared to the base and / or the object.163. The method of any of the previous clauses, wherein the membrane is configured to first couple to the object and conform to a shape of the object, and then couple to the base.164. The method of any of the previous clauses, wherein the membrane forms a known tunable interface configured for coupling the object to the base.165. The method of any of the previous clauses, wherein the membrane and the base are mechanically separate when the membrane couples to the object.166. The method of any of the previous clauses, wherein mechanically separate comprises deformable relative to each other, flexible relative to each other, and / or loosely connected to each other.167. The method of any of the previous clauses, wherein the membrane and the base are mechanically connected, while still allowing the membrane to move independently, during clamping.168. The method of any of the previous clauses, wherein an interface between the membrane and the base is relatively low friction compared to another interface between the membrane and the object, when the membrane is coupled to the object.169. The method of any of the previous clauses, wherein a friction level at the interface between the membrane and the base is adjustable to provide the relatively low friction when the membrane is coupled to the object, and relatively high friction to clamp the membrane and the object to the base.170. The method of any of the previous clauses, wherein the friction level at the interface between the membrane and the base is adjustable using electrostatic charges, lubrication, specifics shapes of surfaces of the membrane and / or the base, areal friction distribution, capillary clamping, mechanical flexures, locally confined gasses and / or liquids, and / or surface roughness.171. The method of any of the previous clauses, wherein the membrane comprises a plurality of sub portions interconnected by flexible couplers, the plurality of sub portions interconnected by the flexible couplers configured to at least in part facilitate relative compliance of the membrane compared to the base and / or the object.172. The method of any of the previous clauses, wherein the relative compliance of the membrane causes the membrane to conform to a topology of the object when the membrane is coupled to the object.173. The method of any of the previous clauses, wherein the flexible couplers comprise relatively thinner areas of the membrane compared to relatively thicker areas which form the plurality of sub portions.174. The method of any of the previous clauses, wherein each of the plurality of sub portions comprises one or more burls configured to contact the object, with minimal lateral shear between each burl and the object because of the relative compliance of the membrane.175. The method of any of the previous clauses, wherein each of the plurality of sub portions has a square, rectangular, hexagonal, octagonal, or round shape.176. The method of any of the previous clauses, wherein the holding force and / or the coupling force is an electrostatic force, a mechanical force, a vacuum force, a magnetic force, and / or a chemical force.177. The method of any of the previous clauses, wherein the electrostatic force is coulombic or Johsen- Rahbek based.178. The method of any of the previous clauses, wherein the membrane is configured to facilitate relatively low friction during object loading, to prevent in-plane deformations; and facilitate relatively high friction during semiconductor lithography exposure, to prevent the object from slipping during acceleration and local heating.179. The method of any of the previous clauses, wherein a thermal conductivity of the membrane is relatively low compared to the base and / or the object.180. The method of any of the previous clauses, wherein the membrane comprises burls, with intermediate areas comprising a relatively soft material compared to the burls.

[0154] 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 with the 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.

[0155] 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, a reticle clamp alone, the membrane, and / or the associated lithography apparatus may comprise separate embodiments, and / or these features may be used together in the same embodiment.

[0156] 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 clamping system for a lithography apparatus, comprising: a base configured to provide a holding force configured to removably hold an object; and a membrane configured to be removably coupled to the base and engage the object, the membrane comprising: a first surface configured to contact the base; a second, opposite surface, for engaging the object; and a coupler configured to provide a coupling force to removably couple the membrane to at least one of the object and the base.

2. The system of claim 1 , wherein the base comprises one or more base electrodes configured to provide electrostatic force configured to removably hold at least one of the membrane and the object, the one or more base electrodes are configured to be energized and deenergized to provide or remove the electrostatic force.

3. The system of claim 1, wherein the coupler comprises one or more electrode layers, each electrode layer comprising one or more membrane electrodes configured such that electrostatic force capacitively couples the membrane to at least one of the base and the object.

4. The system of claim 1 , wherein the membrane is permeable to cooling gas provided from the base such that the cooling gas is provided at a first interface between the base and the membrane and at a second interface between the membrane and the object.

5. The system of claim 1, further comprising a tool handler comprising a membrane installation tool configured for contacting the membrane to at least one of the object and the base, wherein the membrane installation tool comprises a surface and at least one end stop configured to support the membrane in a contacting position.

6. The system of claim 1 , further comprising at least one of a plurality of first burls at a first interface between the base and the membrane, and a plurality of second burls at a second interface between the membrane and the object.

7. The system of claim 1, wherein the membrane comprises a plurality of sub portions interconnected by flexible couplers, the plurality of sub portions interconnected by the flexible couplers configured to at least in part facilitate relative compliance of the membrane compared to at least one of the base and the object.

8. A membrane configured to be removably coupled to at least one of a base and an object, the membrane configured to be positioned between the base and the object, the membrane comprising: a first surface configured to contact the base; a second, opposite surface configured to contact the object; and a couple configured to provide a coupling force to removably couple the membrane to at least one of the base and the object.

9. The membrane of claim 8, wherein the coupler comprises one or more electrode layers, each electrode layer comprising one or more membrane electrodes configured such that electrostatic force capacitively couples the membrane to at least one of the base and the object.

10. The membrane of claim 8, wherein the membrane is permeable to cooling gas provided from the base such that the cooling gas is provided at a first interface between the base and the membrane and at a second interface between the membrane and the object.

11. The membrane of claim 8, further comprising at least one of a plurality of first burls protruding from the first surface and configured to contact the base, and a plurality of second burls protruding from the second surface and configured to contact the object.

12. The membrane of claim 8, further comprising a plurality of sub portions interconnected by flexible couplers, the plurality of sub portions interconnected by the flexible couplers configured to at least in part facilitate relative compliance of the membrane compared to at least one of the base and the object.

13. A clamping method for a lithography apparatus, the method comprising: providing, with a base of the lithography apparatus, a holding force configured to removably hold an object; and removably coupling a membrane to the base, and engaging the object with the membrane, the membrane comprising: a first surface configured to contact the base; a second, opposite surface, for engaging the object; and a coupler configured to provide a coupling force to removably couple the membrane to at least one of the object and the base.

14. The method of claim 13, further comprising: positioning, via a tool handler, the membrane between the base and the object;wherein the tool handler comprises a membrane installation tool configured for contacting the membrane to at least one of the object and the base, wherein the membrane installation tool comprises a surface and at least one end stop configured to support the membrane in a contacting position.

15. The method of claim 13, wherein the membrane comprises a plurality of sub portions interconnected by flexible couplers, the plurality of sub portions interconnected by the flexible couplers configured to at least in part facilitate relative compliance of the membrane compared to at least one of the base and the object.

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