Nozzle for providing gas flow, method for creating a nozzle

Abstract

This disclosure provides a nozzle for providing a gas outflow. The nozzle comprises a main channel, the main channel opening at its downstream end into at least one flow-restricting section, each flow-restricting section having a plurality of parallel vanes for generating a uniform gas flow, and at least one flow-restricting section opening into its respective outflow section having a cross-sectional area that increases toward its open end, adapted to provide a gas outflow.

Description

[Technical Field]

[0001] [Cross-reference to related applications] This application claims priority to European application 23167139.7, filed on 6 April 2023, which is incorporated herein by reference in its entirety.

[0002] [Technical field] The present invention relates to a nozzle for providing a gas flow, and a method for creating such a nozzle. The nozzle can be used, for example, in a lithography apparatus. [Background technology]

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

[0004] To project a pattern onto a substrate, a lithography apparatus may use electromagnetic radiation. The wavelength of this radiation determines the minimum size of the features that can be formed on the substrate. A lithography apparatus using extreme ultraviolet (EUV) radiation with wavelengths in the range of 4–20 nm (e.g., 6.7 nm or 13.5 nm) may be used to form smaller features on a substrate than a lithography apparatus using radiation with a wavelength of, for example, 193 nm.

[0005] Gas flow may be applied at various locations in a lithography apparatus for various functions.

[0006] US2017363975 discloses a lithography apparatus that injects gas between a patterning device and a patterning device masking blade to protect the patterning device from contamination. The gas may be injected into a space defined between the patterning device and the patterning device blade by one or more gas supply nozzles provided on at least one side of the patterning device. One or more gas supply nozzles are coupled to a frame on which the patterning device support structure moves relative to. Each nozzle may be configured and provided to supply gas over at least the patterning area of ​​a reflective patterning device.

[0007] US2005157278 discloses an exposure apparatus that can maintain the reflectivity of mirrors and transmittance of lenses, and can maintain initial performance over a long period of time by using exposure light in the vacuum ultraviolet region wavelengths to illuminate a mask and transfer the image of the pattern on the mask to a substrate. The apparatus provides an optical path space through which exposure light passes with a gas mainly composed of inert or noble gases, and a gas feed unit for introducing a predetermined concentration of hydrogen into the gas fed to at least a portion of the optical path space. In the lithography process, the required gas flow rate, gas composition, and pressure conditions may change from step to step of the process. Typical gas compositions may vary, for example, from hydrogen gas for one application to XCDA (extreme clean dry air) or nitrogen for other applications. During operating conditions, the nozzle may have to operate in near vacuum, for example, on the order of 3-5 Pa. Here, the gas composition may mainly consist of hydrogen. Other gases, such as the aforementioned XCDA, may be used to perform intermittent flushing operations. For this purpose, the gas may flow through the nozzle at an increased flow rate. The environment may be set to an intermediate pressure between low vacuum and atmospheric pressure. The intermediate pressure may be in the near-vacuum range, for example, 0.5–1 kPa. Furthermore, the nozzle may need to be operational during maintenance of the lithography equipment, and the optical section may be partially open to atmospheric pressure (approximately 1 bar). Other conditions with other gas compositions and / or other pressure environments may also apply. [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] Detailed laboratory tests and practical applications of conventional nozzles have shown that conventional gas flow devices often exhibit relatively non-uniform gas flow. Alternatively, because conventional nozzles may be optimized for specific gas flow rates and gases, the flow may become non-optimal and non-uniform for other flow rates, other gas compositions, and / or other pressure environments. The consequence of non-uniform flow is the existence of dead-circulation zones, i.e., zones where flow is minimal or absent. In such zones, particles can accumulate and contaminate the device. For example, near vulnerable parts such as wafer stages, masks, and protective pellicles in the optical path of high-end lithography equipment, particle contamination and accumulation are preferably prevented as much as possible.

[0009] Thus, there is a need for improved gas flow devices that provide a more uniform flow. The objective is to provide a nozzle that can provide a substantially uniform gas flow for multiple gas compositions, fluctuating gas flow rates, and / or multiple pressures. [Means for solving the problem]

[0010] This disclosure provides a nozzle for providing a gas outflow. The nozzle comprises a main channel, the main channel opening at its downstream end into at least one flow-restricting section, each flow-restricting section having a plurality of parallel vanes for generating a uniform gas flow, and at least one flow-restricting section opening into its respective outflow section having a cross-sectional area that increases toward its open end, adapted to provide a gas outflow.

[0011] In one embodiment, the main channel branches into at least two branch channels, preferably two branch channels, and each branch channel opens into its respective flow-restricting section at the downstream end of each branch channel of the main channel.

[0012] In one embodiment, the main channel includes at least one flow distribution section at the downstream end, and the sides of the at least one flow distribution section open into respective flow restriction sections.

[0013] In one embodiment, the cross-sectional area of the at least one flow distribution section decreases towards the downstream end.

[0014] In one embodiment, at least two branch channels branch out from the main channel, each flow distribution section is directed inward, and the downstream end of one flow distribution section faces the downstream end of the other flow distribution section.

[0015] In one embodiment, the nozzle includes a first plate in which the main channel, the flow restriction section, the outflow section, and an optionally branched channel are recessed, and a second plate covering at least the main channel and the branched channel in the first plate. In one embodiment of the nozzle with branch channels, the branch channels may also be recessed in the first plate.

[0016] In one embodiment, a gap exists between at least a part of the vanes, preferably the upper ends of all the vanes, and the second plate.

[0017] According to another aspect, the present disclosure provides a lithographic apparatus comprising at least one nozzle as described above.

[0018] The lithographic apparatus may comprise an illumination section, a reticle stage, a projection system, a first aforementioned nozzle provided at the interface between the illumination section and the reticle stage, and / or a second aforementioned nozzle provided at the interface between the reticle stage and the projection system.

[0019] In one embodiment, at least one nozzle provides a uniform gas flow along the opening such that it blocks particle swarms from passing through the opening while allowing radiation to pass through the opening.

[0020] In another aspect, the present disclosure provides a method for manufacturing a nozzle as described above.

[0021] According to this aspect, the present disclosure provides a method for providing a main channel and providing at least one flow-restricting section at the downstream end of the main channel, each flow-restricting section having a plurality of parallel vanes for generating a uniform gas flow, wherein at least one flow-restricting section opens into a respective outflow section having a cross-sectional area that increases toward its open end, adapted to provide a gas outflow.

[0022] In one embodiment, the method comprises the steps of recessing a main channel, two branched channels, a flow limiting section, and an outflow section in a first plate, and covering the first plate with a second plate so as to cover at least the main channel, two branched channels, and a flow distribution section.

[0023] In one embodiment, the method comprises the steps of placing a brazing foil between a first plate and a second plate, and connecting the first plate to the second plate by brazing.

[0024] In one embodiment, notch patterns corresponding to at least one, preferably all, of the main channel, the branch channel, the flow limiting section, and the outflow section are provided on the brazing foil such that one or more of the channels and / or sections are not brazing foil.

[0025] The nozzles and methods of this disclosure are adapted to provide a relatively uniform gas flow. Here, an outflow section or diffuser mixes multiple parallel flows from parallel flow channels to provide a uniform outflow. The nozzles may be adapted to provide a gas flow into a vacuum space.

[0026] The nozzles and methods of this disclosure enable a relatively uniform gas flow. The result of the uniformity of the gas flow is improved cleanability. Cleanability here refers to the limited deposition of contaminants and particles with respect to the absence of dead zones. The nozzles and methods of this disclosure are suitable for providing a gas curtain to shield one section of a lithography apparatus from other sections. [Brief explanation of the drawing]

[0027] Embodiments of the present invention are described below for illustrative purposes only, with reference to the following accompanying schematic drawings. Figure 1 shows a lithography system comprising a lithography apparatus and a radiation source. Figure 2 shows a perspective view of one embodiment of the nozzle according to the present disclosure. Figures 3A and 3B show bottom views of the respective embodiments of the plate section of the nozzle according to this disclosure. Figure 4 shows a cross-sectional view of one embodiment of the nozzle outflow section according to the present disclosure. Figure 5 shows a schematic top view of one embodiment of the details of the nozzle outflow section of the present disclosure. Figure 6 shows a cross-section in the longitudinal direction of Figure 5. Figure 7 shows a front view of the nozzle of this disclosure. Figure 8 shows a cross-sectional view along line III-III in Figure 3A. Figure 9 shows a schematic diagram illustrating the gas outflow in the outflow section of the nozzle of this disclosure. [Modes for carrying out the invention]

[0028] Figure 1 shows a lithography system comprising a radiation source SO and a lithography apparatus LA. The radiation source SO is configured to generate an EUV radiation beam B and supply the EUV radiation beam B to the lithography apparatus LA. The lithography apparatus LA comprises an illumination system IL, a support structure MT configured to support a patterning device MA (e.g., a mask), a projection system PS, and a substrate table WT configured to support a substrate W. The support structure MT and the patterning device may be located in a device section represented as a reticle stage RS. Openings 15, 16 may be provided in the walls at the interfaces between the reticle stage, the illumination section IL, and the projection system PS to allow radiation to pass from one section to the other.

[0029] The illumination system IL is configured to adjust 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. Both the faceted field mirror device 10 and the faceted pupil mirror device 11 provide the EUV radiation beam B with a desired cross-sectional shape and a desired intensity distribution. The illumination system IL may include other mirrors or devices in addition to or instead of the faceted field mirror device 10 and the faceted pupil mirror device 11.

[0030] After this adjustment, the EUV radiation beam B interacts with the patterning device MA. As a result of this interaction, a patterned EUV radiation beam B' is generated. The projection system PS is configured to project the patterned EUV radiation beam B' onto the substrate W. For this purpose, the projection system PS may include a number of mirrors 13, 14 configured to project the patterned EUV radiation beam B' onto the substrate W, which is held by the substrate table WT. The projection system PS may apply a reduction factor to the patterned EUV radiation beam B' to form an image with features smaller than the 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 in Figure 1 as having only two mirrors 13, 14, the projection system PS may include a different number of mirrors (e.g., six or eight mirrors).

[0031] 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 previously formed pattern on the substrate W.

[0032] In the radiation source SO, the illumination system IL, and / or the projection system PS, a small amount of gas (e.g., hydrogen) may be provided at a relatively low vacuum, i.e., a pressure well below atmospheric pressure.

[0033] The radiation source SO shown in Figure 1 is of a type that may be represented, for example, as a laser-generated plasma (LPP) source. For example, the laser system 1, which may include a CO2 laser, is configured to inject energy via a laser beam 2 into a fuel, such as tin (Sn), provided by a fuel emitter 3. In the following description, tin is referred to, but any suitable fuel may be used. The fuel may be, for example, liquid, or it may be, for example, 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-forming region 4. The laser beam 2 is incident on the tin in the plasma-forming region 4. The injection of laser energy into the tin generates a tin plasma 7 in the plasma-forming region 4. During the de-excitation and recombination of electrons and plasma ions, radiation, including EUV radiation, is emitted from the plasma 7.

[0034] EUV radiation from the plasma is collected and focused by a collector 5. The collector 5 comprises, for example, a near-normal incident radiation collector 5 (often more commonly referred to as a normal incident radiation collector). The collector 5 may have a multilayer mirror structure arranged to reflect EUV radiation (e.g., EUV radiation having a desired wavelength such as 13.5 nm). The collector 5 may have an elliptical configuration with two foci. As described later, the first focal point may be in the plasma-forming region 4, and the second focal point may be in the intermediate focal point 6.

[0035] The laser system 1 may be spatially separated from the radiating source SO. In this case, the laser beam 2 may be delivered from the laser system 1 to the radiating source SO by a beam delivery system (not shown) including, for example, a suitable directional mirror and / or beam expander and / or other optical elements. The laser system 1, the radiating source SO, and the beam delivery system may together be interpreted as the radiating system.

[0036] The radiation reflected by collector 5 forms EUV radiation beam B. EUV radiation beam B is focused at 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 intermediate focus 6 acts as a virtual radiation source for the illumination system IL. The radiation source SO is positioned such that the intermediate focus 6 is located at or near the aperture 8 in the closed structure 9 of the radiation source SO.

[0037] Figure 1 shows a radiation source SO as a laser-generated plasma (LPP) source, but any suitable source such as a discharge-generated plasma (DPP) source or a free-electron laser (FEL) may be used to generate EUV radiation.

[0038] Generally with reference to Figures 2, 3A, and 3B, the nozzle 18 of the present disclosure comprises a main channel 20. The main channel 20 branches into two branch channels 30, 32. Each branch channel may have its respective flow distribution section 34, 36 at its downstream end. The flow distribution sections 34, 36 are fluidly connected to their respective flow limiting sections 22c, b.

[0039] Each flow-restricting section has a plurality of parallel vanes 24 for generating a uniform gas flow. Each flow-restricting section opens into an outflow section 26, which has a cross-sectional area that increases toward its open end 28, adapted to provide gas outflow. In actual embodiments, flow-restricting sections 22b, 22c of two adjacent branch channels may jointly constitute a single flow-restricting section 22 with vanes 24 that open into the outflow section 26. Flow-restricting sections 22d, 22e of second branch channels 30a, 32a may jointly constitute a second flow-restricting section 22a.

[0040] The main channel may include at least one flow distribution section 34, 36 at its downstream end, the side of which at least one flow distribution section opens into the respective flow limiting sections 22c, 22d. At least one flow distribution section 34, 36 may have a tapered shape with a cross-section that narrows toward the downstream end 38. Thus, the gas flow in the channel is uniformly distributed across the flow limiting section 22, limiting dead flow at any given gas flow rate. The distribution sections 34, 36 may be referred to as a split manifold chamber. The flow limiting section 22 may be referred to as a vane limiting area. The outflow section 26 may be referred to as a diffuser area.

[0041] The two branch channels 30 and 32 may branch outward from the main channel, and their respective flow distribution sections 34 and 36 are oriented inward, with the downstream end of each flow distribution section 34 facing the downstream end of the other flow distribution section 36.

[0042] In one embodiment (Figure 3B), the nozzle 18 may comprise a first portion 19 and a second portion 21 surrounding a slit or opening 25. The opening 25 may function, for example, as an opening between each part or section of a lithography apparatus LA. For example, the opening 25 may be located at the interface between an illumination section IL and a reticle section having a mask table MT, and / or at the interface between a projection system PS and a section having a mask table MT.

[0043] The second section 21 may comprise a second main channel 20a. The second main channel may branch into two second branch channels 30a, 32a. Each second branch channel may have its respective flow distribution section 34a, 36a at its downstream end. The flow distribution section is fluidly connected to its respective flow limiting section 22d, 22e. In a practical embodiment, the flow limiting sections 22d, 22e of two adjacent second branch channels 30a, 32a may jointly constitute a single second flow limiting section 22a with vanes 24 that open into a single second outflow section 26a. Each flow limiting section has a plurality of parallel vanes 24 for generating a uniform gas flow. The second flow limiting section 22a opens into the second outflow section 26a, having a cross-sectional area that increases toward its open end 28a, adapted to provide a gas outflow.

[0044] The branch channels 30, 30a, 32, and 32a may have gently curving flow paths. To enable smooth and substantially laminar flow throughout the channel, the flow paths should be as gentle and organic as possible, avoiding or completely eliminating sharp or right angles. Here, the branch channels may have a kind of onion-shaped flow path (see Figures 3A and 3B).

[0045] In one embodiment, a first outflow section 26 and a second outflow section 26a are provided facing each other along the sides of the opening 25. Here, the gas flow from the first and second outflow sections can be directed along the surface of the opening 25 to create a gas curtain covering the opening 25.

[0046] In actual embodiments, the nozzle 18 may comprise a first plate 40 and a second plate 42. Gas flow channels, such as the main channel 20 and branched channels 30, 32, may be recessed in the first plate 40. The channels may be formed, for example, by milling, etching, or pressing. In actual embodiments, the channels are formed by removing material from the first plate 40 to create notches for gas flow. The same may apply to the embodiment shown in Figure 3B.

[0047] The second plate 42 may cover the first plate 40. The second plate may be connected to the first plate by any suitable means, including, for example, adhesive bonding, soldering, brazing, welding, bolting, screwing, welding, and / or riveting. The bonding may include adhesive bonding based on cyanoacrylate or epoxy. The edges of the two plates 40, 42 may be bolted together in combination with a reinforcing structure, for example, a block or ridge (not shown).

[0048] When the second plate 42 is connected to the first plate 40, the channel is enclosed by the plate material, providing an airtight channel for guiding the gas flow. Thus, the second plate 42 forms part of the wall of the gas flow channel. The second plate 42 may cover only a portion of the first plate 40. At a minimum, the second plate 42 covers the gas flow channels in the first plate, such as the main channel 20, branch channels 30, 32, and flow-restricting section 22.

[0049] The brazing foil 44 may be provided, for example, between a first plate and a second plate, where the first plate may be connected to the second plate by brazing. Preferably, the brazing foil 44 is provided with notch patterns corresponding to at least each main channel 20, 20a and the corresponding branch channel. During brazing, the notch patterns ensure that there is no brazing material in the channel, preventing contamination of the gas flow channel by the brazing material. In addition, the notch patterns in the brazing foil facilitate cleaning of the gas flow channel of the nozzle 18 without causing brazing material to accumulate in the channel during cleaning. Cleaning here may involve flowing pressurized gas or fluid.

[0050] Alternative embodiments may include, but are not limited to, a modification in which multiple vanes are combined to form a larger “island” (such an “island” may be connected to a second plate); a modification having a single channel opening into a single flow-limiting section (and thus without branch channels); and an embodiment in which, instead of branch channels, the nozzle has two additional channels connected to their respective gas source inlets, and the inlets directly connecting to their respective flow-limiting sections. Other options include, for example, connecting one or more vanes, which may have a greater height than the other vanes, to the second plate for stability by point welding, bonding, brazing, etc.

[0051] Figure 4 shows a cross-section of a flow-restricting section 22 having a plurality of parallel vanes 24 that generate fluid flow openings 48 between the vanes. The vanes 24 may extend upward from the first plate 40 toward the second plate 42. A gap 50 may be provided between one or more upper ends of the vanes and the second plate 42. In actual embodiments, almost all or all of the vanes leave at least some space between the upper ends of the vanes 24 and the second plate 42. In actual embodiments, the vanes may extend over about 50% to 90% of the height 52 of the flow-restricting section 22. Some of the vanes, for example, one or two, may have the aforementioned greater height and may extend from the first plate to the second plate to provide additional support. Vanes extending from the first plate to the second plate may be connected to the second plate 42.

[0052] Generally, referring to Figure 5, the flow limiting section 22 may be connected to the sides of the respective flow distribution sections 34, 36, etc. As shown in Figures 2 and 3, each flow distribution section may have a cross-sectional area that decreases from its upstream end to its downstream end. Here, referring to Figure 6, for example, the height of each flow distribution section 34 may remain substantially constant, while its width decreases. This contributes to the gas flow being distributed substantially evenly across the fluid flow openings 48 between the vanes 24.

[0053] Referring to Figures 6, 7, and 8, the channels 20, 30, the flow distribution section, the flow limiting section 22, and the outflow section 26 may be provided as recesses in the first plate 40. Here, each gas flow section may be provided by removing material, for example, by milling or etching. The outflow section 26 may be provided with an inclined wall, the downstream end 28 having a height that exceeds the height at the upstream end of the outflow section 26 (i.e., the end connected to the flow limiting section 22). As shown in Figures 6 and 7, the height of the flow distribution section 34 may significantly exceed the height of the flow limiting section 22.

[0054] In one embodiment, one or more channels (i.e., including a main channel 20 and its branch channels 30, 32) may be partially provided on the first plate 40 and the other part on the second plate 42. Here, the flow limiting section may typically be provided on one of the plates.

[0055] In actual embodiments, the first plate 40 may have a thickness on the order of 1 to 5 mm, for example, about 1.5 to 2.5 mm. The second plate may have a thickness on the order of 0.3 to 5 mm, for example, about 0.5 to 1 mm. The vanes may have a height on the order of 0.1 to 0.5 mm. The vanes may have a width on the order of 1 to 5 times their height. The fluid flow openings 48 may have a width on the order of 1 to 4 times the width of the vanes. The outflow section 26 may have inclined walls set at an angle of about 5 to 10%. The flow channels 20, 30, 32 and / or flow distribution sections 34, 36 may have a height on the order of at least 2 to 10 times the height of the flow limiting section 22.

[0056] The nozzle 18 of this disclosure includes a unique inner channel geometry within the nozzle. The nozzle provides a combination of a “split manifold” design using flow distribution sections 34, 36, etc., a defined “restricting area” with a flow restricting section 22 accompanied by small vanes 24, and a defined “diffuser area” 26. Tests have shown that the nozzle of this disclosure overcomes the challenge of designing each of these areas to satisfy and exceed thresholds for flow uniformity and cleanability, while satisfying other nozzle requirements (including, but not limited to, volume claims, manufacturability, pressure drop, mechanical stress, and natural frequency) for all flow conditions.

[0057] The uniformity of the gas outflow flow (applicable to all flow conditions) allows the nozzle to function as a gas curtain between sections of the lithography apparatus. Thus, the nozzle can functionally protect the reticle stage RS and the patterning device (reticle) and pellicle from any particles moving upward, limiting the accumulation of localized contamination. The nozzle design allows for cleaning of the nozzle on all internal surfaces and local outer nozzle areas during servicing, ventilation, and verification.

[0058] As shown, flow uniformity can be achieved for all flow conditions, including relatively low flow rates (exposure H2) and relatively high flow rates (using N2 and / or XCDA for service, aeration, and verification). As a result, the nozzle design of this disclosure has several essential advantages over conventional nozzle designs, including proven flow uniformity (actual TNO testing vs. in-line CFD simulation). Nozzle 18 offers positive short-term expectations regarding cleanliness (CFD simulation RME area and particle tracing, removal of "dead circulation zones"). The nozzle allows for "flow switching" during exposure (for designs with two opposing gas flows as shown in Figure 3B). The nozzle allows for flushing from two directions (for two-nozzle designs).

[0059] Flow uniformity is achieved by utilizing a “split manifold” design. Flow limits generate a high penalty if the flow is not uniformly distributed. The challenge is to design the limits in Section 22 for all flow conditions (i.e., device conditions) without excessively consuming the pressure drop budget.

[0060] Referring to Figure 5, for uniform flow, the pressure difference ΔP = P across the limiting section up -P downis preferably large enough. The threshold value for the pressure difference may vary for each flow state (e.g., low Reynolds number vs. high Reynolds number, and low Mach number vs. high Mach number).

[0061] The ideal gas law equation is ρ = p / R S T. For an ideal isothermal gas in a restricted section with a high aspect ratio (h ≪ W), P up 2 -P down 2 =(24μLQ down P down ) / (Wh 3 ). Rearranging this equation gives a means to express the pressure drop across the restricted section. The pressure drop across the gas in the restricted section is P up 2 -P down 2 =(24μLmR S T) / (Wh 3 ) = Cm scales. Here, m is the mass flow rate [kg / s]. The mass flow rate here may be equal to the volume flow rate Q [m 3 / s] multiplied by the density r of the gas [kg / m 3 . L is the length [m] of the flow channel 48 of the restricted section, W is the width [m] of the flow channel, and h is the height [m] of the flow channel 48. T is the temperature [K]. The viscosity of the gas is indicated by μ [Pa.s]. R S is the specific gas constant [J / kg.K]. P is the pressure [Pa].

[0062] For the low-pressure state (e.g., during exposure), P down ≪P up . Since P up = √(C × m), then P up -P down ≒ √(C × m).

[0063] For the high-pressure state and / or higher gas flow rate (e.g., service, ventilation, verification), the pressure drop across the flow restriction section 22 is relatively small. Therefore, P downP up Equivalent to P up -P down ≈√(C×m+P) down 2 )-P down This is the result.

[0064] Thus, the effect of pressure drop is reduced under high-pressure flow conditions. As a solution, the nozzle flow limiting section of the present disclosure includes a relatively large number of relatively narrow vanes distributed over a relatively wide low-limiting section to distribute the flow under these conditions. The reducing cross-section of the flow distribution section, e.g., the reducing width, can be adjusted to provide a relatively uniform flow distribution over all parallel flow channels 48. For example, the flow limiting section may have more than 20, e.g., more than 30, e.g., more than 50 vanes.

[0065] The flow uniformity enabled by the nozzles of this disclosure has been confirmed in actual testing, both in simulations and in prototyping in laboratory environments. Figure 9, intended for illustrative purposes only and not to scale, shows the gas outflow uniformity of the limiting section as a function of dimensions along the width of the limiting section. For example, because the vanes are relatively thin and narrow relative to the width of the limiting section, the gas outflow mixes in the downstream outflow section, providing a uniform gas outflow exiting the nozzle.

[0066] The nozzle design of this disclosure is optimized to have relatively high flow uniformity and cleanability. The nozzle provides uniform flow in several different flow conditions for both small and large gas flow rates. These flow conditions may include: 1) hydrogen flow (H2) during exposure (low pressure, e.g., near-vacuum environment of 1-10 Pa); 2) flushing at intermediate pressures; and 3) maintenance at substantial atmospheric pressure.

[0067] Furthermore, the absence of brazing foil on the channel (only between the contacting plate surfaces) enhances cleanliness. The nozzle features offer combined benefits. The restricted area generates a uniform flow under vacuum conditions. When combined with vanes, a uniform flow can also be generated under atmospheric pressure conditions. In addition, the nozzle has improved cleanliness because dead zones are virtually prevented.

[0068] The nozzle 18 of this disclosure may be applied as a gas curtain to cover an opening in a lithography apparatus LA. For example, the opening 25 of the nozzle 18 may be provided to cover one or both of the openings 15, 16 at the interface between the reticle stage and the illumination section IL and / or the reticle stage RS and the projection system PS. In use, the nozzle of this disclosure can provide a uniform gas flow that covers each of the openings 15, 16 with a gas curtain, allowing radiation to pass from one section to the other while blocking the passage of particle swarms.

[0069] While this text may have provided specific references 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 manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memory, flat panel displays, liquid crystal displays (LCDs), thin-film magnetic heads, and the like.

[0070] While specific references may be made in this text to embodiments of the present invention in the context of lithography apparatus, embodiments of the present invention may be used in other apparatuses. Embodiments of the present invention may constitute part of a mask inspection apparatus, a measuring apparatus, or any apparatus for measuring or processing objects such as wafers (or other substrates) or masks (or other patterning devices). These apparatuses may generally be referred to as lithography tools. Such lithography tools may operate under vacuum conditions or atmospheric (non-vacuum) conditions.

[0071] While specific references to the use of embodiments of the present invention may have been made in the context of optical lithography, it is understood 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.

[0072] Although specific embodiments of the present invention have been described above, it is understood that the present invention may be implemented in ways different from those described. The above description is for non-limiting illustrative purposes only. Features of each embodiment may be combined, for example. Accordingly, it will be apparent to those skilled in the art that modifications may be made to the described invention without departing from the scope of the claims set forth below.

Claims

1. A nozzle for providing gas outflow, Equipped with a main channel, The main channel opens at its downstream end into at least one flow-restricting section, each flow-restricting section having a plurality of parallel vanes for generating a uniform gas flow. The at least one flow-restricting section opens into each outflow section, having a cross-sectional area that increases toward its open end, adapted to provide the gas outflow. nozzle.

2. The aforementioned main channel branches into two branch channels. Each branch channel opens into its respective flow-restricting section at its downstream end. The nozzle according to claim 1.

3. The main channel comprises at least one flow distribution section at its downstream end. The side of the at least one flow distribution section opens into the respective flow limiting section. The nozzle according to claim 1 or 2.

4. The nozzle according to claim 3, wherein the cross-sectional area of ​​at least one flow distribution section decreases toward the downstream end.

5. The two branch channels mentioned above branch outward from the main channel, Each of the aforementioned flow distribution sections is oriented inward, The downstream end of one flow distribution section faces the downstream end of the other flow distribution section. The nozzle according to claim 3 or 4.

6. The main channel, the flow limiting section, and the outflow section are recessed in the first plate, A second plate covering at least the recessed main channel, the flow limiting section, and the outflow section in the first plate, A nozzle according to any one of claims 1 to 5, comprising:

7. The nozzle according to claim 6, wherein a gap exists between the upper end of the vane and the second plate.

8. A lithography apparatus comprising at least one nozzle according to any one of claims 1 to 7.

9. Lighting section, Reticle stage and The projection system and, A first nozzle provided at the interface between the illumination section and the reticle stage, and / or a second nozzle provided at the interface between the reticle stage and the projection system, A lithography apparatus according to claim 8, comprising:

10. The lithography apparatus according to claim 8 or 9, wherein at least one nozzle provides a uniform gas flow along the opening such that it blocks a group of particles from passing through the opening while allowing radiation to pass through the opening.

11. A method for manufacturing a nozzle, Steps to provide the main channel, The step of providing at least one flow-restricting section at the downstream end of the main channel, wherein each flow-restricting section has a plurality of parallel vanes for generating a uniform gas flow, Equipped with, The at least one flow-restricting section opens into each outflow section, having a cross-sectional area that increases toward its open end, adapted to provide a gas outflow. method.

12. The first plate includes the steps of recessing the main channel, the flow limiting section, and the outflow section, The steps include covering the first plate with the second plate so as to cover at least the main channel, the two branched channels, and the flow limiting section, The method according to claim 11, comprising:

13. The steps include: placing a brazing foil between the first plate and the second plate; The steps include connecting the first plate to the second plate by brazing, The method according to claim 12, comprising:

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