Clamp for holding an object, method of making the same, and related lithographic system

Abstract

The present invention provides a clamp comprising: a dielectric component; a conductive element disposed on the dielectric component and made of a first conductive material; and a plurality of segments disposed on the conductive element for supporting an object, each segment comprising a second conductive material, wherein the clamp comprises a stack of an etch-resistant material and a third conductive material in an interleaved layer disposed between the conductive element and the plurality of segments.

Description

Technical Field

[0001] The present invention relates to a clamp and method for clamping an object. The clamp may be an electrostatic clamp. The clamp is, for example, part of a wafer support system. The object may be, for example, a wafer, substrate, or shrink reticle in a lithography apparatus. Prior Art

[0002] A lithography apparatus is a machine designed to apply a desired pattern to a substrate. Lithography apparatuses are used, for example, in the manufacture of integrated circuits (ICs). For example, a lithography apparatus can project a pattern from a patterning device (e.g., a mask) onto a layer of radiation-sensitive material (resist) provided on the substrate.

[0003] As semiconductor manufacturing processes continue to advance, the size of circuit elements has steadily decreased over the past few decades, while the number of functional components, such as transistors, per device has steadily increased, following a trend commonly known as "Moore's Law." To keep pace with Moore's Law, the semiconductor industry is pursuing technologies that enable the creation of ever-smaller features. Lithography equipment uses electromagnetic radiation to project patterns onto substrates. The wavelength of this radiation determines the minimum size of features patterned on the substrate. Typical wavelengths currently in use are 365 nm (i-line), 248 nm (KrF), 193 nm (ArF), and 13.5 nm (EUV). Compared to lithography equipment using radiation with a wavelength of, for example, 193 nm, lithography equipment using extreme ultraviolet (EUV) radiation with wavelengths ranging from 4 nm to 20 nm (e.g., 6.7 nm or 13.5 nm) can be used to form even smaller features on substrates.

[0004] At such short wavelengths, precise positioning of the patterning device and / or substrate within the lithography apparatus is necessary.

[0005] Such lithography equipment may be equipped with one or more chucks to clamp the patterning device and / or substrate, respectively, to an object support, such as a mask stage or wafer stage. These chucks may be, for example, mechanical, vacuum, or electrostatic chucks. Electrostatic chucks are particularly well-suited for operation at EUV wavelengths, as regions of EUV lithography equipment must operate under near-vacuum conditions. Near-vacuum, as used herein, may refer to pressures in the range of 5 kPa and lower, or in the range of 1 to 10 Pa.

[0006] At such short wavelengths, precise positioning of the patterning device and / or substrate within the lithography apparatus is necessary.

[0007] Such lithography equipment may be equipped with one or more chucks to clamp the patterning device and / or substrate to an object support, such as a mask stage or wafer stage. These chucks may be mechanical, vacuum, or electrostatic. Electrostatic chucks are particularly well-suited for operation at EUV wavelengths, as regions of EUV lithography equipment must operate under near-vacuum conditions.

[0008] Some electrostatic wafer chucks have a dielectric surface containing (equally spaced) metal lines, referred to in the art as "Manhattan lines," that conductively connect protrusions or "bumps" that define a plane for clamping the patterned device and / or substrate.

[0009] Due to high-volume use, where thousands or even tens of thousands of wafers are produced daily, the initial relative roughness of the top surface of the protrusions decreases over time. As the top surface smooths, it begins to adhere to the wafers, which are also relatively smooth. This stickiness slows down the lithography process and ultimately risks damaging the wafers. To eliminate this problem, the wafer holder is typically trimmed at some point. Trimming involves etching or stripping the protrusions. The etching step removes any metal or conductive material. The structure is then deposited again. However, this process is relatively time-intensive and expensive.

[0010] It is an object of at least one embodiment of at least one aspect of the present invention to obviate or at least mitigate at least one of the above-identified disadvantages of the prior art. Summary of the Invention

[0011] A clamp for clamping an object, the clamp comprising: A dielectric member; a conductive element disposed on the dielectric component and composed of a first conductive material; and A plurality of nodes are arranged on the conductive element for supporting the object, Each nodule comprises a second conductive material, The fixture includes a stack of alternating layers of etch-resistant material and a third conductive material disposed between the conductive element and the plurality of nodes.

[0012] In one embodiment, the first conductive material, the second conductive material, and the third conductive material are the same.

[0013] In one embodiment, the first conductive material, the second conductive material and / or the third conductive material include chromium nitride (CrN).

[0014] In one embodiment, the etch-resistant material comprises Si.

[0015] In one embodiment, the stack has a total thickness of about 0.5 mm to 20 mm.

[0016] In one embodiment, the stack comprises at least two layers of etch-resistant material.

[0017] In one embodiment, the stack includes at least four etch-resistant material layers and at least three third conductive material layers.

[0018] In one embodiment, each layer of the stack has a thickness of about 50 nm to 1 mm.

[0019] The chuck may be an electrostatic wafer chuck.

[0020] According to another aspect, the present invention provides a lithography system including a clamp as described in Technical Solution 1.

[0021] According to another aspect, the present invention provides a clamp for clamping an object, the clamp comprising: A plurality of nodes configured to support the object, each node comprising a first conductive material, The plurality of nodules are on top of a stack of an interleaved layer comprising a layer of an etch-resistant material and a layer of a second conductive material, a removal rate of the etch-resistant material is lower than a removal rate of the first conductive material when the plurality of nodules are removed, and a bottom portion of the plurality of nodules is formed by the stack of interleaved layers.

[0022] According to another aspect, the present invention provides a method for manufacturing a clamp for clamping an object, the method comprising the following steps: - A conductive element composed of a first conductive material is placed on a dielectric member; - arranging a plurality of nodes for supporting the object on the conductive element, Each nodule comprises: a top portion comprising a second conductive material; and a bottom portion comprising a stack of alternating layers of an etch-resistant material and a third conductive material.

[0023] The method may comprise the following steps; - removing the top portion of the nodules by etching; - depositing a new second layer of conductive material on the dielectric component; - depositing a plurality of etch-resistant material dots on the new second conductive material layer; - removing the second conductive material by etching; and - Remove those spots of etch resist material. Simple diagram description

[0024] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which: - Figure 1 depicts a lithography system including a lithography apparatus and a radiation source; - Figure 2 depicts a perspective view of a portion of an electrostatic fixture having a plurality of conductive nodes connected by Manhattan lines; - Figure 3 depicts a top view of the nodule and the Manhattan line; - Figures 4 to 7 schematically depict cross-sections of a nodule during subsequent steps of an embodiment of a method for producing a nodule; and - Figures 8 to 12 schematically depict cross-sections of a nodule during subsequent steps of an embodiment of a method for trimming a nodule. Implementation Method

[0025] [Cross-reference to related applications] []

[0026] This application claims priority from European patent application No. 21205594.1, filed on October 29, 2021, which is incorporated herein by reference in its entirety.

[0027] FIG1 shows a lithography system including a radiation source SO and a lithography apparatus LA. The radiation source SO is configured to generate an EUV radiation beam B and to supply the EUV radiation beam B to the lithography apparatus LA. The lithography apparatus LA includes an illumination system IL, a support structure MT configured to support a patterning device MA (e.g., a mask), a projection system PS, and a substrate table WT configured to support a substrate W.

[0028] The illumination system IL is configured to condition the EUV radiation beam B before it is incident on the patterning device MA. In addition, the illumination system IL may include a faceted field mirror device 10 and a faceted pupil mirror device 11. Together, the faceted field mirror device 10 and the faceted pupil mirror device 11 provide a desired cross-sectional shape and a desired intensity distribution for the EUV radiation beam B. The illumination system IL may include other mirrors or devices in addition to or in place of the faceted field mirror device 10 and the faceted pupil mirror device 11.

[0029] After such conditioning, the EUV radiation beam B interacts with the patterning device MA. This interaction produces a patterned EUV radiation beam B'. The projection system PS is configured to project the patterned EUV radiation beam B' onto a substrate W. To this end, the projection system PS may include a plurality of mirrors 13, 14 configured to project the patterned EUV radiation beam B' onto a substrate W held by a substrate table WT. The projection system PS may apply a reduction factor to the patterned EUV radiation beam B', thereby forming an image having features that are smaller than corresponding features on the patterning device MA. For example, a reduction factor of 4 or 8 may be applied. Although the projection system PS is illustrated as having only two mirrors 13, 14 in FIG. 1 , the projection system PS may include a different number of mirrors (e.g., six or eight).

[0030] The substrate W may include a previously formed pattern. In this case, the lithography apparatus LA aligns the image formed by the patterned EUV radiation beam B' with the pattern previously formed on the substrate W.

[0031] A relative vacuum, ie, a small amount of gas (eg, hydrogen) at a pressure well below atmospheric pressure, may be provided in the radiation source SO, in the illumination system IL, and / or in the projection system PS.

[0032] The radiation source SO shown in FIG1 is of a type that may be referred to as a laser-produced plasma (LPP) source, for example. A laser system 1, which may, for example, comprise a CO2 laser, is configured to deposit energy via a laser beam 2 into a fuel, such as tin (Sn), provided by, for example, a fuel emitter 3. Although tin is mentioned in the following description, any suitable fuel may be used. The fuel may, for example, be in liquid form and may, for example, be a metal or alloy. The fuel emitter 3 may include a nozzle configured to direct tin, for example, in the form of droplets, along a trajectory toward a plasma formation region 4. The laser beam 2 is incident on the tin at the plasma formation region 4. The deposition of laser energy into the tin generates a tin plasma 7 at the plasma formation region 4. Radiation, including EUV radiation, is emitted from the plasma 7 during deexcitation and recombination of electrons and ions in the plasma.

[0033] EUV radiation from the plasma is collected and focused by a collector 5. The collector 5 comprises, for example, a near-normal-incidence radiation collector 5 (sometimes more commonly referred to as a normal-incidence radiation collector). The collector 5 may have a multi-layer mirror structure configured to reflect EUV radiation (e.g., EUV radiation having a desired wavelength, such as 13.5 nm). The collector 5 may have an ellipsoidal configuration with two focal points. The first of the focal points may be at the plasma formation region 4, and the second of the focal points may be at an intermediate focus 6, as discussed below.

[0034] The laser system 1 can be spatially separated from the radiation source SO. In this case, the laser beam 2 can be transferred from the laser system 1 to the radiation source SO with the aid of a beam delivery system (not shown) comprising, for example, suitable guide mirrors and / or a beam expander and / or other optical devices. The laser system 1, the radiation source SO, and the beam delivery system can be collectively considered a radiation system.

[0035] The radiation reflected by the collector 5 forms an EUV radiation beam B. The EUV radiation beam B is focused at an intermediate focus 6 to form an image at the intermediate focus 6 of the plasma present in the plasma formation region 4. The image at the intermediate focus 6 serves as a virtual radiation source for illuminating the system IL. The radiation source SO is configured so that the intermediate focus 6 is located at or near an opening 8 in an enclosure 9 of the radiation source SO.

[0036] Although FIG. 1 depicts the radiation source SO as a laser produced plasma (LPP) source, any suitable source such as a discharge produced plasma (DPP) source or a free electron laser (FEL) may be used to generate EUV radiation.

[0037] 2 , a substrate table WT may include a chuck 200, also referred to as a chuck, configured to clamp a substrate W to a substrate support WT. The main body of the electrostatic chuck typically corresponds in shape and size to the substrate W. The chuck 200 has protrusions 210 and 215, also referred to as knobs, on at least its upper surface 205 (e.g., the surface facing the substrate W during use). These knobs extend from the upper surface 205 to define a plane in which the substrate W is held.

[0038] It should be understood that the term "upper" is used in the context of the example lithography apparatus LA of FIG1 . Herein, the electrostatic chuck 200 is depicted in a particular orientation. It should be understood that the disclosed chuck can be positioned in a variety of orientations, and thus the term "upper" should be understood in the context of the specific described use case.

[0039] In one embodiment, there may be hundreds, thousands, or tens of thousands of nodules distributed across a chuck having a diameter of, for example, 200 mm, 300 mm, or 450 mm. The tips of the nodules typically have a small area, for example, less than 1 mm², such that the total area of ​​all nodules extending from the upper surface of the electrostatic chuck 245 is less than about 10% of the total surface area of ​​the upper surface. Due to this nodule configuration, any particles that may be on the surface of the substrate W, the electrostatic chuck 200, or the substrate support WT are likely to land between the nodules and, therefore, will not cause deformation of the substrate or substrate holder. The patterned nodule configuration can be regular or can be varied as needed to provide the appropriate distribution of force on the substrate W and substrate support WT.

[0040] 2 depicts a perspective view of a portion of a dielectric member 245 of the electrostatic chuck 200. The dielectric member 245 has a surface 205, such as a surface that faces the substrate W during use.

[0041] The depicted portion shows a first nodule 210 and a second nodule 215. Each nodule 210, 215 may include or consist of a conductive layer or coating. Nodules 210, 215 are coupled to a conductive element 220. The dielectric surface 205 of the electrostatic chuck 200 may include a plurality of such conductive elements 220. The conductive elements or lines 220 may be arranged in a generally repeating and / or regular pattern, which may be referred to as "Manhattan lines." The surface of the nodules touching the object (e.g., wafer) may have the same voltage or may be grounded.

[0042] The conductive element 220 can be disposed on or embedded in a dielectric surface 205 of the electrostatic chuck 200. The conductive element 220 can be elevated, e.g., not flush, relative to the dielectric surface 205 of the electrostatic chuck 200. Alternatively, the conductive element 220 can be embedded in the surface 205 (not shown).

[0043] Additionally or alternatively, the electrostatic chuck 200 depicted in FIG. 2 may be configured as a chuck to electrostatically hold a lithographic projection reticle or reticle negative in at least one of a lithographic projection apparatus, a reticle handling apparatus, and a reticle manufacturing apparatus.

[0044] Although the nodules 210, 215 are depicted as cylindrical in Figures 2 and 3, it should be understood that the nodules 210, 215 may have other shapes suitable for supporting an object, such as a substrate W or a reticle (not shown). In some embodiments, the nodules 410, 415 have the same shape and dimensions throughout their height. In other embodiments, the nodules 210, 215 may be wedge-shaped. The nodules 210, 215 may also vary in size. For example, the nodules in different embodiments may protrude by a distance ranging from approximately 1 micron to approximately 5 millimeters.

[0045] 2 shows only two nodules 210, 215, it should be understood that the image of the electrostatic chuck 200 includes many more nodules, such as hundreds, thousands, or even tens of thousands of nodules. The nodules together define a plane for supporting an object such as a substrate W.

[0046] Furthermore, for example purposes only, the conductive element 220 is depicted as straight; for example, the knobs 210 and 25 are arranged along a linear path defined by the straight conductive element 220. In one exemplary embodiment, the electrostatic chuck may include a plurality of straight conductive elements 220 arranged in parallel or in another pattern, with the knobs also arranged in a straight line. In other embodiments falling within the scope of the present disclosure, the conductive element 220 may have different shapes or configurations, such as curves, circles, or spirals. In some embodiments, the conductive element 220 may be configured to extend radially from the periphery and / or center of the dielectric surface 205.

[0047] In some embodiments, the nodes may be arranged in concentric rings on the surface 205 of the dielectric member 245. A plurality of conductive elements may extend between and connect each of the plurality of nodes arranged in the rings.

[0048] As described above, the conductive element 220 may be disposed in a trench (not shown) formed on the surface 205 of the dielectric member 245. The trench may be formed with sloped sidewalls. For example, in some embodiments, the slope angle may be between 30 and 40 degrees relative to the plane defined by the surface 205 of the dielectric member 245. Such sloped sidewalls may be formed by a wet etching process.

[0049] 4 to 7 , an embodiment of a method for manufacturing a jig including at least one nodule 210 according to the present invention may include the following steps.

[0050] FIG4 shows a first step, which includes depositing a first layer 250 of a first conductive material. This first layer 250 will ultimately form Manhattan lines 220. The method includes depositing a second composite layer or stack 252 on top of first layer 250. Stack 252 comprises a plurality of alternating layers 254 and 256 of an etch stop material (layer 254) and a second conductive material (layer 256), respectively. A third layer 258 of a third conductive material is deposited on top of stack 252. A fourth layer 260 of an etch stop material is deposited on top of third layer 258. Layer 260 forms a mask for the ultimate formation of one or more nodules 210. Nodules 210 have a thickness between 1 mm and 100 mm, preferably between 5 mm and 15 mm.

[0051] In one embodiment, the first conductive material, the second conductive material, and / or the third conductive material may comprise chromium nitride (CrN), diamond-like carbon (DLC), or a similarly suitable material. Etch stop layers 254 and / or 260 may comprise Si or a similarly suitable material. In one embodiment, the deposition steps for each of the layers 250, 254, 256, 258, and 260 may all occur in the same deposition chamber, wherein the input of the deposition material is adjusted. That is, the input to the deposition chamber may be changed from a certain conductive material to a certain etch stop material, depending on, for example, the desired thickness of each layer, the deposition rate of each material, etc. In one embodiment, the first conductive material, the second conductive material, and / or the third conductive material may comprise the same material.

[0052] Each layer 254, 256 of stack 252 may have a thickness of approximately 50 nm to 1 mm, preferably between 80 nm and 300 nm. Stack 252 may have a thickness of approximately 0.2 mm to 20 mm, preferably between 0.4 mm and 1 mm. First layer 250 may have a thickness of approximately 0.2 mm to 10 mm, preferably between 0.4 mm and 1 mm. Third layer 258 may have a thickness of approximately 0.5 mm to 15 mm, preferably between 5 mm and 11 mm. Stack 252 may include at least one or two sets of alternating layers of conductive material and etch stop material. Adding more alternating layers to stack 252 may enable additional trimming steps, as explained herein below with reference to Figures 8 through 12. In one embodiment, stack 252 may include at least four layers of conductive material 256 sandwiched between at least five layers of etch stop material 254. The etch stop material and the conductive material may be selected so that each material can be selectively removed. "Selectively" herein means that one material can be removed (e.g., by wet etching or ion beam forming) while another material is substantially unaffected by the removal step, and vice versa. For example, when the nodules 210 are partially or completely removed, the etch-resistant material has a lower removal rate than the removal rate of the nodules 210. When the plurality of nodules are removed, the removal rate of the etch-resistant material is between 1 / 10 and 1 / 10,000 of the removal rate of the first conductive material of the nodules, preferably between 1 / 20 and 1 / 1,000, and more preferably between 1 / 50 and 1 / 200.

[0053] FIG5 shows the result of the second step, in which the conductive material of third layer 258 has been removed. Removal may include, for example, etching, ion beam shaping, or laser shaping. The masking function of layer 260 ensures that the portion of layer 258 covered by mask 260 remains, thereby forming one or more nodules 210. Layer 220 is covered by a multilayer stack 252, comprising intervening layers of, for example, Si and CrN. The conductive material (typically CrN) of layer 250 immediately below the second etch stop in the designed "Manhattan" structure 220 must also be removed. The multilayer etch stop of layers 262 and 264 is extremely etch-resistant. For example, laser processing allows for the removal of the entire etch stop multilayer of stack 252 in locations where the coating is not expected to remain on the surface of substrate 254, resulting in the structure shown in FIG5.

[0054] FIG6 shows the next step. Here, the sections of first layer 250 not covered by stack 252, which includes an etch stop material, are removed. This removal is performed, for example, by wet etching, ion beam shaping, or laser shaping. The top layer of etch stop material 254 serves to protect the conductive material layer covered by it. Stack 252 will have approximately the same area as layer 220 as seen in the top view of the fixture. The combination of stack 252 and layer 220 can be patterned as Manhattan lines.

[0055] In another embodiment, stack 252 can be deposited directly on dielectric member 245 and patterned as Manhattan lines. Layer 220 may not be present. Stack 252 can be sufficiently conductive to connect the nodes.

[0056] FIG7 shows a subsequent step in which the etch stop material is removed. This step removes layer 260 covering the nodule 210 and also removes the etch stop material from layer 254 not covered by the nodule 210. Removal may include wet etching or ion beam forming. As shown in FIG7 , the removal step may remove only the first layer 262, or both the first layer 262 and the second layer 264 of etch stop material. During the removal of the etch stop material, the first conductive stack 266 may have been removed, with the second conductive stack 268 now partially exposed. The removal step in FIG7 may involve, for example, ion beam forming (IBF). Ion beam forming does not terminate at the etch stop layers 262 and 264. Instead, ion beam forming removes material to a predetermined depth. IBF uses a relatively wide beam (much larger than the typical diameter of the nodule 210) and is intended to flatten the nodule tip. The latter drives the amount of material removed. Thus, the amount of layers 262, 264, 266 of stack 252 that are affected by the IBF removal step is driven by the need to remove material from the top of the nodule. When ion beam shaping is used, the thickness of layer 260 is selected to be less than the thickness of stack 252. Depending on the selected number of possible trims, the thickness of layer 260 is, for example, at most half, such as about one-third, or, for example, at most one-quarter, of the total thickness of stack 252.

[0057] FIG7 shows a cross-section of a burl 210 on an associated Manhattan line 220, ready to hold an object such as a wafer, mask, or reticle. The at least one burl 210 shown in FIG7 is typically part of a fixture of the present invention. The fixture itself includes numerous burls, as shown in FIG7 . Layer 254, comprising an etch-resistant material, and layer 256, comprising a conductive material, have approximately the same area when viewed from above. Layer 256 substantially completely overlaps layer 254.

[0058] As shown in FIG7 , due to the subsequent step of removing the etch stop material, the bottom portion of the nodule is formed by the stack of interleaved layers 252. Comparing the stack of interleaved layers 252 in FIG4 and FIG7 , the portion of the stack 252 not covered by the nodule has been removed. Therefore, the bottom portion of the nodule shown in FIG7 includes portions of the stack of interleaved layers, which are indicated in FIG7 by reference numerals 262, 264, and 266.

[0059] FIG8 shows a cross section of a burl 210 with a damaged top surface 270. Damage is typically caused by wear and tear from use, as explained above. The top surface may, for example, become too smooth and thus sticky. Alternatively, the surface 270 may become too rough relative to the intended surface structure.

[0060] FIG9 shows the first step of a method for trimming a fixture. A stack 252 comprising alternating layers of conductive material and etch-stop material enables removal of only the top portion 258, rather than the entire structure. Removal may involve, for example, wet etching to remove the conductive material of the nodule 210. Etching may also remove the sides of one conductive material layer 272 included in the stack 252. A subsequent layer 274 of etch-stop material terminates the etching process. Thus, the stack 252 protects the underlying layer 220 of conductive material (typically CrN) from etching. The number of alternating sets of materials in the stack 252 can determine the number of possible rework passes. For example, using a stack of approximately nine alternating layers 254, 256, two to three rework or trimming passes may be possible.

[0061] FIG10 shows the subsequent steps. Here, a layer 276 of conductive material is deposited on the structure of FIG9. A masking layer 278, similar to layer 260 shown in FIG4, is deposited on top of layer 276. Layer 276 essentially redeposits the nodule layer 210. Layer 278 adds a structural mask that determines the shape of the nodule.

[0062] FIG11 shows the next step, which involves removing unwanted material. Removal herein may include etching, typically wet etching. The conductive material of layer 276 not covered by masking layer 278 may be removed by wet etching. Etch stop layer 274 included in stack 252 stops the etching process to protect Manhattan lines 220.

[0063] 12 depicts a subsequent step that includes removing the mask 274. Removing the mask 278 may include ion beam forming (IBF). The IBF process may also remove portions of the etch stop layer 274 exposed by the nodules 210.

[0064] FIG12 shows a cross-section of a burl 210 on an associated Manhattan line 220, ready to hold an object such as a wafer, mask, or reticle. The at least one burl 210 shown in FIG12 is typically part of a fixture according to the present invention. The fixture itself includes numerous burls, as shown in FIG12 . Thus, the fixture according to the present invention can be trimmed in a limited number of steps, as described with respect to FIG8 through FIG12 . The method according to the present invention avoids removing and subsequently redepositing the entire structure including the Manhattan line 220. Thus, trimming provides a significant savings in time and associated costs.

[0065] As shown in Figures 8 to 12, the bottom portion of the burl is formed by a stack of interleaved layers 252. Comparing the stacks of interleaved layers 252 in Figures 8 and 12, we can see that due to the trimming process, the portion of the stack 252 not covered by the burl has been removed. Therefore, the stack of interleaved layers 252 forming the bottom portion of the burl in Figure 12 has become thicker and now includes additional layers compared to the burl as shown in Figure 8.

[0066] When a nodule is damaged, as shown in Figure 8, it may be necessary to trim the nodule. In conventional systems, the etch stop layer has already disappeared. Therefore, the entire nodule, including the Manhattan line, and all conductive structures are removed and redeposited. This is time-consuming and labor-intensive. Instead of a single etch stop layer, the jig of the present invention has a multilayer stack, such as CrN and Si, allowing the Si layer to serve as multiple interfaces for etch stop. Therefore, after each trimming, the jig can be returned to a "Manhattan line present" state, allowing for faster and less expensive jig trimming. The Manhattan line present state, as used herein, refers to a predetermined structure of the conductive line 220 that remains substantially intact during trimming.

[0067] In one embodiment, bottom portion 220 may be, for example, approximately 1 μm thick. The conductive material of wire 220 may be made of CrN (conductive). This portion may be referred to as a "Manhattan" wire. Essentially, wire 220 is a thin-film interconnect that electrically connects all nodes 210, 215 to a reference voltage, referred to as ground. The top portion of the nodes is made of CrN, for example. Each node 210, 215 may have a height of approximately 9 mm.

[0068] Although specific reference may be made herein to the use of lithography equipment in IC manufacturing, it should be understood that the lithography equipment described herein may have other applications. Possible other applications include the fabrication of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads, and the like.

[0069] Although specific reference may be made herein to embodiments of the present invention in the context of lithography equipment, embodiments of the present invention may be used in other equipment. Embodiments of the present invention may form part of mask inspection equipment, metrology equipment, or any equipment that measures or processes objects such as wafers (or other substrates) or masks (or other patterning devices). Such equipment may generally be referred to as lithography tools. Such lithography tools may utilize vacuum conditions or ambient (non-vacuum) conditions.

[0070] Although the above may have made specific reference to the use of embodiments of the present invention in the context of optical lithography, it will be appreciated that the present invention is not limited to optical lithography and may be used in other applications, such as imprint lithography, where the context permits.

[0071] Although specific embodiments of the present invention have been described above, it will be appreciated that the invention may be practiced in other ways than as described. The above description is intended to be illustrative rather than restrictive. Therefore, it will be apparent to those skilled in the art that modifications may be made to the invention as described without departing from the scope of the claims set forth below.

[0072] Clauses 1. A method for manufacturing a clamp for clamping an object, the method comprising: A plurality of nodes are configured to support an object, each node comprising a first conductive material, The plurality of nodules are on top of a stack of alternating layers comprising a layer of etch-resistant material and a layer of second conductive material, and when the plurality of nodules are removed, the removal rate of the etch-resistant material is lower than the removal rate of the first conductive material. 2. The method of clause 1, wherein the stack is disposed above a dielectric component, the method further comprising: removing the plurality of nodules; depositing a layer comprising the first conductive material on the dielectric member; depositing a layer comprising the etch-resistant material on the layer of the first conductive material; Patterning the layer comprising the etch-resistant material to form another plurality of nodules; removing the first conductive material by etching to form the additional plurality of nodules; and The layer comprising the etch-resistant material is removed.

[0073] 1: Laser system 2: Laser beam 3: Fuel Launcher 4: Plasma formation area 5: Collector 6: Middle focus 7: Tin plasma 8: Open your mouth 9: Enclosed structure 10: Faceted field mirror device 11: Faceted pupil mirror device 13: Mirror 14: Mirror 200: fixture 205: Surface 210: First tubercle / protrusion 215: Second tubercle / protrusion 220: Conductive element 245: Dielectric components 250: First floor 252: Stack 254: Layer 256: Layer 258: Third layer / top section 260:Layer 4 / Mask 262: First floor 264: Second floor 266: first conductive stack layer 268: second conductive stack layer 270: Top surface 272: Layer 274:Mask 276: Layer 278: Layer B: EUV radiation beam B': Patterned EUV radiation beam IL: Irradiation System LA: Lithography Equipment MA: Patterned Device MT:Support structure PS: Projection system SO: Radiation source W: substrate WT: substrate table

Claims

1. A clamp for holding an object, the clamp comprising: a plurality of segments configured to support the object, each segment comprising a first conductive material, wherein the plurality of segments are on top of a stack of alternating layers comprising a layer of etch-resistant material and a layer comprising a second conductive material, wherein when the plurality of segments are removed, the removal rate of the etch-resistant material is lower than the removal rate of the first conductive material, and wherein the bottom portion of the plurality of segments is formed by the stack of the alternating layers.

2. The fixture of claim 1, wherein the stack is configured to connect at least two of the plurality of nodules.

3. The fixture of claim 1 or 2, wherein when the plurality of nodules are removed, the removal rate of the etch-resistant material is between 1 / 10 and 1 / 10000 of the removal rate of the first conductive material.

4. The fixture of any one of claims 1 to 2, wherein the fixture further comprises a conductive element contained in a third conductive material beneath the stack, the conductive element being configured to electrically connect at least two of the plurality of nodules.

5. The fixture of claim 4, wherein the etch-resistant material protects the conductive element when the plurality of nodules are removed.

6. The fixture of claim 4, wherein the first conductive material, the second conductive material, and the third conductive material are the same or contain CrN.

7. The fixture of any one of claims 1 to 2, wherein the etch-resistant material comprises Si.

8. The fixture of any one of claims 1 to 2, wherein the stack has a total thickness between 0.2 mm and 20 mm.

9. The fixture of any one of claims 1 to 2, wherein the stack comprises at least two layers of the etch-resistant material, or wherein each layer of the stack has a thickness between 50 nm and 1 mm.

10. The fixture of claim 4, wherein the stack comprises at least four layers including an etch-resistant material and at least three layers including the third conductive material.

11. The fixture, as described in any of claims 1 to 2, is an electrostatic wafer fixture.

12. A fixture as claimed in any of claims 1 to 2, wherein the layer containing the etch-resistant material and the layer containing the second conductive material have approximately the same area when viewed from a top view of the fixture.

13. A lithography system comprising a fixture as described in claim 1.

14. A method of manufacturing a clamp for holding an object, the method comprising the steps of: placing a conductive element made of a first conductive material on a dielectric component; and distributing a plurality of segments for supporting the object on the conductive element, wherein each segment includes: a top portion comprising a second conductive material; and a bottom portion comprising a stack of alternating layers of an etch-resistant material and a third conductive material.

15. A method of manufacturing a clamp for holding an object, the method comprising: configuring a plurality of segments for supporting the object, each segment comprising a first conductive material, wherein the plurality of segments are on top of a stack of alternating layers comprising a layer of etch-resistant material and a layer comprising a second conductive material, wherein when the plurality of segments are removed, the removal rate of the etch-resistant material is lower than the removal rate of the first conductive material, wherein the bottom portion of the plurality of segments is formed by the stack of alternating layers.

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