Apparatus and method for controlling contaminant diffusion in an EUV radiation source

Abstract

Systems and methods for generating extreme ultraviolet (EUV) radiation from a target material in a source vessel are disclosed, in which a gas stream carries target material vapor and some of the target material is deposited on a surface within the vessel that accumulates target material, and measures are taken in the vessel to reduce the amount of deposited target material that can re-enter the gas stream.

Description

Related applications

[0001] This application claims priority to U.S. Patent Application No. 63 / 571,098, filed March 28, 2024, entitled “APPARATUS AND METHOD FORCONTROLLING CONTAMINANT DISPERSAL IN EUV RADIATION SOURCE”, which is incorporated herein by reference in its entirety. Technical Field

[0002] This disclosure relates to apparatus and methods for generating extreme ultraviolet (“EUV”) radiation from plasma produced by the conversion of target material in a source container (e.g., a plasma generation chamber). Specifically, this disclosure relates to apparatus and methods for controlling the diffusion of target material within a chamber in a system for generating EUV radiation. Background Technology

[0003] Light generated by a radiation source can be used in exposure apparatuses in semiconductor manufacturing processes. Examples of such exposure apparatuses are photolithography apparatuses, measurement or inspection apparatuses, more specifically mask inspection apparatuses, and even more specifically photochemical mask inspection apparatuses.

[0004] A photolithography apparatus is a machine configured to apply a desired pattern to a substrate. For example, photolithography apparatuses can be used in the fabrication of integrated circuits (ICs). For instance, a photolithography apparatus can project a pattern from a patterning device (e.g., a mask) onto a layer of radiation-sensitive material (e.g., a photoresist or photoresist) disposed on a substrate. To project a pattern onto the substrate, a photolithography apparatus can use electromagnetic radiation. The wavelength of this radiation determines the minimum feature size that can be formed on the substrate. For example, a photolithography apparatus using EUV radiation with wavelengths in the range of 4–20 nanometers (e.g., 6.7 nanometers or 13.5 nanometers) can be used to form smaller features on a substrate than a photolithography apparatus using, for example, radiation with a wavelength of 193 nanometers.

[0005] Methods for generating EUV radiation involve converting a target material into a plasma state. The target material includes at least one element having one or more emission lines in the EUV portion of the electromagnetic spectrum, such as xenon, lithium, or tin. The target material can be solid, liquid, or gas. In a method commonly known as laser-generated plasma (LPP), the desired plasma can be generated by irradiating and converting a target material having the desired line-emitting element using a radiation source, such as a laser beam.

[0006] One LPP technique involves generating a stream of droplets of target material and irradiating at least some of the droplets with one or more laser pulses. Radiation sources using this technique generate EUV radiation by coupling laser energy into the target material having at least one EUV emitting element, thereby creating a highly ionized plasma with an electron temperature of tens of electron volts.

[0007] In this process, plasma is typically generated in a source container (e.g., a vacuum chamber), and various characteristics of the generated EUV radiation are monitored using corresponding types of measurement equipment.

[0008] The processes used to generate EUV radiation from plasma typically also produce undesirable byproducts within the plasma chamber. These byproducts can include out-of-band radiation, high-energy ions, and debris, such as atoms and / or clumps / droplets of target material. These processes can also generate target material vapor, which can lead to the accumulation of target material pools or clumps at various locations within the chamber. In the case of tin as the target material, tin vapor can cause the formation of tin flocs that can obstruct orifices in chambers such as gas circulation systems, which will be described in detail below. In this document, target material debris byproducts are sometimes referred to as stray target material, and stray target material and target material vapor are sometimes collectively referred to as waste target material.

[0009] Stray target materials can also impede the propagation of EUV radiation within the chamber. EUV radiation is emitted from the plasma in various directions. In a common arrangement, a near-perpendicular incident mirror (often referred to as a "collector mirror" or simply a "collector") is positioned to collect, guide, and, in some arrangements, focus at least a portion of the radiation to an intermediate focal point. At the wavelengths involved, the collector is preferably implemented as a multilayer mirror ("MLM"). As its name suggests, the MLM typically consists of alternating layers of material (MLM stacks) on a substrate or base plate. System optics can also be configured as coated optics, even if they are not implemented as MLMs.

[0010] The collected radiation can then be relayed from the central location to a set of optical elements, a mask, a detector, and finally to the scanner. Thus, the path of EUV radiation in the chamber is defined by a cone with the collector optics as its base and the central focal point of the collector optics as its apex.

[0011] In some systems, buffer gases are used to establish flow patterns within the chamber, thereby protecting the collector optics and removing plasma generation byproducts. For example, molecular hydrogen (H2) gas at pressures ranging from about 0.5 mbar to about 3 mbar can be used as a buffer gas in a vacuum chamber to control target material diffusion and thus reduce debris. In the absence of gas, under vacuum pressure, it is difficult to adequately protect the collector from target material debris ejected from the irradiated area. Hydrogen is relatively transparent to EUV radiation at wavelengths of about 13.5 nm and is therefore superior to other candidate gases such as helium (He), argon (Ar), or other candidate gases that exhibit high absorption rates at about 13.5 nm.

[0012] An airflow is established within the chamber to prevent target material from accumulating on the plasma-facing surfaces within the chamber. For example, the airflow can be established in a direction perpendicular to the collector's reflective surface. This flow is called forward flow, and it is typically directed to one or both of the collector's primary and intermediate foci. Additionally, the gas can be directed to flow substantially along the collector's reflective surface. This flow is called lateral flow. Another flow along the collector surface from its periphery to its center can be called peripheral flow.

[0013] These flows—forward, lateral, and perimeter flows—work together to protect the collector from plasma debris, while the lining flows manage the deposition of target material along the container sidewalls. These flows then merge with flows in the lower cone to guide target material vapor out of the source via exhaust.

[0014] Despite these measures, managing the diffusion of stray target material remains a technical challenge. The process of converting target material into vapor and particles deposits residual target material on every surface with an unobstructed path between the irradiation site and the surface, and also in the exhaust path of the gas carrying the residual target material.

[0015] Using tin as the target material example, as another mitigation measure, a device called a scrubber can be placed in a chamber to capture the target material. The scrubber has surfaces heated to above the melting point of tin (approximately 232°C), over which an airflow, including target material fragments and vapor, passes, and tin deposits. On these surfaces, the tin melts (or remains molten) and is diverted to the capture container via a drain system. This measure removes the tin from the buffer gas before it passes further through the exhaust chain, thus preventing tin contamination of sensitive exhaust components such as valves and pumps. However, it is possible that liquid tin accumulates along the outlet path at one or more locations inside the source container facing the plasma (e.g., the area around the drain). However, during its accumulation, the liquid tin may be exposed to hydrogen radicals from the plasma in the source (…). In the presence of hydrogen radicals, such as those generated during EUV production, liquid tin tends to sputter, thus ejecting tin back into the chamber gas flow pattern. This phenomenon is sometimes referred to as "tin sputtering." Once back into the gas flow, liquid tin can diffuse to various locations where its presence is destructive, for example, toward and across the central focus, and even into the scanner, resulting in target material buildup in the scanner and on the customer's pellicle and wafer.

[0016] Against this backdrop, a demand has arisen for this publicly available subject matter. Summary of the Invention

[0017] The following provides a brief overview of one or more embodiments to offer a basic understanding of them. This overview is not a comprehensive summary of all contemplated embodiments and is not intended to identify any key or essential elements of the embodiments, nor does it define the scope of any or all embodiments. Its sole purpose is to present some concepts of one or more embodiments in a concise form as an introduction to the more detailed description that follows.

[0018] According to aspects of the embodiments, apparatus and methods for limiting the splashing and sputtering effects of target material are disclosed, and in particular, apparatus and methods for limiting the reintroduction of target material from deposited target material aggregates into the gas flow in a chamber.

[0019] According to an embodiment, an apparatus for generating extreme ultraviolet radiation by irradiating a target material is disclosed. The apparatus includes a chamber; a target material deposition surface arranged to receive deposited target material from a gas flow as the gas flow passes through the target material deposition surface; a drain member in fluid communication with the target material deposition surface, the drain member including a drain member opening and an edge surface adjacent to the drain member opening; and a shield covering at least a portion of the edge surface and positioned to prevent target material from being ejected back into the gas flow.

[0020] The target material deposition surface is coupled to the surface of the scrubber. The surface of the scrubber may include multiple fin structures. The shield may include molybdenum. The thickness of the shield ranges from about 1 mm to about 8 mm. The shield may include at least one of the following materials: titanium, zirconium, and molybdenum. The shield may include stainless steel.

[0021] The target material may include tin, and at least a portion of the surface of the shield is provided with a layer comprising a tin-affinity material. The upper edge of the shield may be curved.

[0022] The shield may have an upper surface and a side surface, wherein the upper surface and the side surface are at an angle, and wherein the shield is oriented in the scrubber such that the upper surface is at an angle relative to gravity in the range of about 0° to about 45°, and the side surface is a plasma-facing surface having an angle relative to gravity in the range of about 20° to about 70°.

[0023] The target material deposition surface may include the surface of the exhaust chamber. The shield is a substantially planar element that extends above and is spaced apart from the drain opening and is inclined relative to the horizontal plane.

[0024] According to another aspect of the embodiments, a target material scrubber for an apparatus for generating extreme ultraviolet radiation by irradiating target material is disclosed. The target material scrubber includes a plurality of target material deposition surfaces arranged such that a gas carrying target material passes over the target material deposition surfaces, thereby transferring the target material from the gas to the target material deposition surfaces. A positioned drain member allows the target material transferred to the target material deposition surfaces to flow to the drain member. The drain member has an edge region, and a shield is positioned over at least a portion of the edge region to prevent the target material from being ejected back into the gas.

[0025] According to another aspect of the embodiments, an apparatus for generating extreme ultraviolet radiation by irradiating target material is disclosed. The apparatus includes a chamber; a waste target material management system disposed within the chamber and configured to discharge gas carrying stray target material, the waste target material handling system including at least one location where liquid waste target material accumulates when the radiation source is operating; and a shield disposed over at least a portion of the location where liquid waste target material accumulates when the radiation source is operating to prevent waste target material from being ejected back into the gas.

[0026] According to another aspect of the embodiments, a method of manufacturing a semiconductor device is disclosed, comprising providing a substrate having a surface with a photoresist layer, directing radiation from a radiation source to the surface with the photoresist layer, the radiation source comprising: a chamber, a waste target material management system disposed within the chamber and configured to discharge gas carrying stray target material, the waste target material handling system comprising at least one location where liquid waste target material accumulates when the radiation source is operating, and a shield disposed over at least a portion of the at least one location where liquid waste target material accumulates when the radiation source is operating to prevent waste target material from being ejected back into the gas, thereby transferring a pattern from a mask onto the photoresist layer, and removing a portion of the photoresist layer to form a pattern on the substrate.

[0027] Other features and advantages of the disclosed subject matter, as well as the structure and operation of various embodiments of the disclosed subject matter, are described in detail below in conjunction with the accompanying drawings. It should be noted that the disclosed subject matter is not limited to the specific embodiments described herein. Such embodiments described herein are for illustrative purposes only. Other embodiments will be apparent to those skilled in the art based on the teachings included herein. Attached Figure Description

[0028] The accompanying drawings (which have been incorporated herein and form part of the specification) illustrate the disclosed subject matter and, together with the description, further assist in explaining the principles of the disclosed subject matter and enable those skilled in the art (one or more) to make and use the aspects described herein. Unless otherwise indicated, the drawings are not drawn to scale.

[0029] Figure 1 This is a schematic diagram of an EUV source.

[0030] Figure 2 This is a schematic diagram of the EUV source, including the washer.

[0031] Figure 3A This is a side view of an EUV source washer.

[0032] Figure 3B It's from another perspective. Figure 3A A side view of the washer.

[0033] Figure 4A This is a diagram of a part of an EUV source scrubber.

[0034] Figure 4B This is a diagram of a part of an EUV source scrubber according to an embodiment.

[0035] Figure 4C This is a perspective view of a portion of an EUV source washer according to an embodiment.

[0036] Figure 5 This is a diagram illustrating the orientation of a drain shield in a portion of a scrubber for an EUV source, according to an embodiment.

[0037] Figure 6 This is a perspective view of a portion of an EUV source washer according to another embodiment.

[0038] Figure 7 This is a schematic diagram of an EUV source including an exhaust chamber.

[0039] Figure 8A This is a schematic diagram of the front end of the exhaust chamber drain component of the EUV source.

[0040] Figure 8BThis is a schematic diagram of the exhaust chamber drain component of the EUV source.

[0041] Figure 9A This is a front view of a portion of an EUV source chamber with an exhaust chamber according to an embodiment.

[0042] Figure 9B This is a side view of a portion of an EUV source chamber with an exhaust chamber according to an embodiment.

[0043] Figure 10 This is a side view of a portion of an EUV source chamber with an exhaust chamber according to an embodiment.

[0044] Figure 11 This is a front view of a portion of an EUV source chamber with an exhaust chamber according to an embodiment.

[0045] Figure 12 This is a side view of a portion of an EUV source chamber with an exhaust chamber according to an embodiment.

[0046] Other features and advantages of the invention, as well as the structure and operation of various embodiments of the invention, are described in detail below in conjunction with the accompanying drawings. It should be noted that the invention is not limited to the specific embodiments described herein. Such embodiments described herein are for illustrative purposes only. The remaining embodiments will be apparent to those skilled in the art based on the teachings included herein. Detailed Implementation

[0047] Various embodiments are now described with reference to the accompanying drawings, wherein like reference numerals denote corresponding elements throughout. In the following description, numerous specific details are set forth for ease of explanation, to facilitate a thorough understanding of one or more embodiments. However, it may be apparent in some or all instances that any of the embodiments described below can be practiced without employing the specific design details described below. In other instances, well-known structures and apparatuses are shown in block diagrams for the convenience of describing one or more embodiments.

[0048] However, it is beneficial to illustrate examples of the environments in which these embodiments may be implemented before describing these embodiments in more detail. In the following description and claims, the terms “upper,” “lower,” “top,” “bottom,” “vertical,” “horizontal,” etc., may be used. Unless otherwise indicated, these terms are intended only to indicate relative orientation and not any orientation related to gravity.

[0049] By first referring to Figure 1The diagram illustrates an exemplary EUV radiation source, such as a laser-generated plasma EUV radiation source 10 according to one aspect of an embodiment. As shown, the EUV radiation source 10 may include a pulsed or continuous laser source 22, for example, a pulsed gas discharge CO2 laser source that generates a radiation beam 12 ranging from about 1 micrometer (μm) to about 10.6 micrometers. The pulsed gas discharge CO2 laser source may have DC or RF excitation, thereby operating at high power and a high pulse repetition frequency.

[0050] The EUV radiation source 10 also includes a target material delivery system 24 for delivering target material in the form of droplets or a continuous liquid flow. In this example, the target material is a liquid, but it can also be a solid or a gas. The target material can be made of tin or tin compounds, although other materials can also be used. In the depicted system, the target material delivery system 24 introduces droplets 14 of target material into the interior of a vacuum chamber 26 having walls 27 until the target material can be irradiated to generate an irradiated region 28 for plasma generation. The vacuum chamber 26 may be lined with a liner 29. It should be noted that the irradiated region used herein is the area where target material irradiation is likely or intended to occur, and is an irradiated region even when no irradiation actually occurs. The EUV source may also include a beam-directed system 32.

[0051] In the system shown, the components are arranged such that the droplet 14 moves substantially horizontally. The direction from the laser source 22 to the irradiated region 28, i.e., the nominal propagation direction of the beam 12, can be considered the Z-axis. The path of the droplet 14 from the target material delivery system 24 to the irradiated region 28 can be considered the X-axis. Therefore, Figure 1 The view is perpendicular to the XZ plane. Although a system in which the droplet 14 moves substantially horizontally is depicted, those skilled in the art will understand that other arrangements in which the droplet moves vertically, or at angles relative to gravity between and including 90° (horizontal) and 0° (vertical), may also be used.

[0052] EUV radiation source 10 may also include EUV source controller system 60, laser ignition control system 65, and beam directional control system 32. EUV radiation source 10 may also include detectors, such as a target position detection system that may include one or more droplet imagers 70, which generates an output indicating the absolute or relative position of the target droplet (e.g., relative to the irradiated area 28) and provides the output to the target position detection feedback system 62.

[0053] like Figure 1As shown, the target material delivery system 24 may include a target delivery control system 90. The target delivery control system 90 operates in response to a signal (e.g., the aforementioned target error, or some quantity derived from the target error provided by the system controller 60) to adjust the path of the droplet 14 through the irradiation region 28. This can be achieved, for example, by repositioning the point at which the target delivery mechanism 92 releases the droplet 14. The release point can be repositioned, for example, by tilting or laterally translating the target delivery mechanism 92. The target delivery mechanism 92 extends into the chamber 26 and is supplied with target material and a gas source from the outside to place the target material within the target delivery mechanism 92 under pressure. The system also includes a target material container 96 for capturing unused droplets of target material (i.e., unconverted target material droplets).

[0054] Continue to refer to Figure 1 The radiation source 10 may also include one or more optical elements. In the following discussion, the collector 30 is used as an example of such an optical element, but the discussion also applies to other optical elements. The collector 30 may be a normal-incident reflector, for example, implemented with an MLM structure having an additional thin barrier layer (e.g., B4C, ZrC, Si3N4, or C) deposited at each interface to effectively block thermally induced interlayer diffusion. Other substrate materials such as aluminum (Al) or silicon (Si) may also be used. The collector 30 may be in the form of an elongated ellipsoid with a central aperture to allow laser radiation 12 to pass through and reach the irradiated region 28. The collector 30 may be, for example, ellipsoidal in shape, having a first focal point at the irradiated region 28 and a second focal point at a so-called midpoint 40 (also referred to as the intermediate focal point), at which EUV radiation can be output from the EUV radiation source 10 and input to, for example, an integrated circuit lithography scanner 50, which uses the radiation, for example, a mask or mask 54, to process the silicon wafer workpiece 52 in a known manner. The silicon wafer workpiece 52 is then additionally processed in a known manner to obtain an integrated circuit device. In some embodiments, the EUV radiation may be input to an inspection device for detecting defects or measuring dimensions during semiconductor manufacturing.

[0055] Figure 2 This is a schematic diagram of an EUV chamber 126 with a scrubber 120. During operation, a buffer gas, such as hydrogen, flows into the chamber 26 through one or more inlets, including a forward flow inlet 100 located at the center of the collector 130. As indicated by hollow arrow A, the buffer gas flows through the chamber 126, past the scrubber 120, and exits through an exhaust outlet 110 and a liner 129, as indicated by hollow arrow B. The intermediate focus of the collector 130 is located at the apex of the EUV beam cone having a bottom surface defined by the collector 130.

[0056] In some embodiments, as indicated by arrow G, the scrubber 120 is tilted relative to gravity, such that liquid target material deposited on the fins or blades of the scrubber 120 flows along the inlet channel 155 in the scrubber 120 to the drain 140. Then, as indicated by arrow T, the liquid target material flows from the drain 140 to the drain module 145 and is thus removed from the interior of the chamber 126.

[0057] Figure 2 A washer 120 with three layers and three drain outlets is shown. Those skilled in the art will understand that a washer may have fewer or more layers.

[0058] Figure 3A This is a front view of an embodiment of the washer 120. It can be seen that... Figure 3A The washer 120 shown has three layers or three stages, each layer having a series of inclined fins 150 and a liquid inlet 155. (As shown) Figure 3A In the directional configuration, the fins 150 on the left side of the washer 120 are tilted from left to right, while the fins 150 on the right side of the washer 120 are tilted from right to left. This creates a series of trapezoidal spaces 152 between the left- and right-tilted fins. Drainage components 140 are disposed on the bottom surface of each trapezoidal space 152.

[0059] Figure 3B yes Figure 3A Side view of the washer 120. Figure 3B In the arrangement shown, the molten target material flows in the direction indicated by the solid black arrow. It can be seen that the molten target material flows downwards along the fin 150 and then along the inlet channel 155 to the corresponding drain element 140. Each drain element 140 is connected to the drain element module 145.

[0060] As previously mentioned, molten target material can accumulate near the drain 140, for example, at the location where the rear wall 160 meets the surface around the opening of the drain 140. Figure 4A An example of an arrangement that could occur in this situation is depicted. For example... Figure 4A As shown, molten target material flows along a predetermined target material flow path T on the upper surface of the inlet channel 155 to the outlet 140. A portion of the flow path T passes through the gap between the upper surface of the inlet channel 155 and the bottom of the rear wall 160. This gap has a width of H. Due to the narrow gap, target material can accumulate at the target material accumulation position 200 on the upstream side of the gap.

[0061] When the molten target material is exposed to hydrogen radicals present in chamber 126, the molten target material sputters. The sputtered target material can re-enter the gas flowing within chamber 126 and move to other parts where harmful sources are present, such as through the central focus and outwards to the scanner or inspection device.

[0062] According to one aspect of the embodiment, contamination is reduced and even avoided by inserting one or more physical barrier members to prevent accumulated target material from splashing back into the gas flowing within the chamber. For example, in cases where target material accumulates around the edges and openings of the drain, the physical barrier member or shield can be partially placed around or upstream of the drain and surround the structure to block target material ejection while allowing the target material to continue to drain below it. Such a shield can be beneficial wherever target material may accumulate in the source. The shield can be configured to be added to a maintainable component of the source that has already been deployed in the field. According to another aspect of the embodiment, the surface of the shield is positioned and angled to allow a thin layer of target material to flow from the shield surface and onto a predetermined drain path, while blocking at least a portion of the line-of-sight path from the accumulation location to the intermediate focal point.

[0063] Therefore, according to aspects of the embodiments, such as Figure 4B As shown, shielding member 170 is positioned to prevent the sprayed molten target material from re-entering the gas flow. Simultaneously, shielding member 170 is positioned to allow molten target material to reach and flow into drain member 140. As... Figure 4C As shown, the shield 170 is mechanically engaged with the fins 150 on both sides of the trapezoidal space 152 and is displaced in the vertical direction from the liquid inlet 155. In the illustrated example, the shield 170 has a top shield surface 175 and a plasma-facing shield surface 180. The surfaces of the shield 170 are angled to facilitate the flow of target material trapped by the shield 170 to the drain 140. Therefore, as... Figure 5 As shown, for example, the top shield surface 175 may have an angle θ1 relative to the horizontal plane, ranging from about 20° to about 90°, more specifically, from about 20° to about 30°. A smaller angle θ1 may allow target material to accumulate on the top shield surface, while a larger angle θ1 may create grooves in which target material can accumulate. For example, the plasma-facing shield surface 180 may have an angle relative to the direction of gravity ranging from about 0° to about 45°, for example, 0°. A larger angle θ2 may widen the gap between the bottom edge of the plasma-facing shield 180 and the target material accumulation location 200, thereby opening a path for the target material to inject itself into the gas, flowing out of the chamber 126 and towards the scanner. In some embodiments, the distance between the bottom edge of the shield 170 and the top surface of the liquid inlet 155 ranges from about 1 cm to about 10 cm. If the distance is less than 1 cm, in some cases, molten target material may easily clog. If the distance is greater than 10 cm, in some cases, the effect of blocking the jet is not significant.

[0064] Typically, the body or core of the shield 170 can be made of materials such as molybdenum or molybdenum alloys (such as titanium-zirconium-molybdenum alloy (TZM)). Other suitable materials include stainless steel. The surface of the shield 170 can be coated to make the material surface more tin-friendly, i.e., similar to water and having hydrophilic properties, giving it a stronger affinity for liquid target materials, thereby causing the molten target material to spread on the surface to maximize contact. For example, in applications where the target material is tin, the shield 170 can be coated with a tin layer.

[0065] Another measure to limit the amount of target material ejected is to constrain the amount of target material allowed to reach the target material accumulation location 200. In other words, the shield can be positioned to prevent liquid target material from flowing to the location where the target material tends to accumulate. Figure 6 This is a perspective view of the arrangement for limiting target material accumulation, wherein the target material accumulation shield 210 is positioned to prevent target material from reaching the surfaces of the rear wall 160 and the drain 140. Figure 6 The target material accumulation location is not visible in the middle. In this embodiment, because the target material accumulation location is blocked by the target material accumulation shield 210, the molten target material flows between the fins and flows to the drain behind the rear wall. The target material accumulation shield 210 can be made of the same material as the shield 170 described above, and can also be coated with a tin-affinity material to promote the flow of molten target material on this surface. It can be seen that the front surface of the target material accumulation shield 210 is tilted at an angle of about 20° to 90° (90° is vertical) relative to gravity.

[0066] In EUV chambers with exhaust chambers in the buffer gas exhaust path, there may be target material accumulation sites near the drain outlet of the exhaust chamber. This arrangement... Figure 7 As shown in the diagram, as indicated by hollow arrow B, buffer gas flows out of chamber 326 defined by chamber wall 327 via exhaust chamber 300. In the depicted arrangement, liquid target material is deposited on the inner surface of exhaust chamber 300 and flows toward drain 310, and from there to drain module 330.

[0067] The target material will be deposited on the surface over which the buffer gas flows. The deposited target material will flow toward the drain 310 and from there into the drain module 330. Generally, it is advantageous to choose an angle relative to gravity around the surface surrounding the drain to allow the liquid target material to flow and escape into the drain. For example, in some embodiments, the angle of the surface should be greater than about 20°. However, even following this principle, complete drainage of the target material cannot be guaranteed, and the target material may still accumulate in the area adjacent to the drain.

[0068] Therefore, this arrangement has the same technical problem as the above arrangement, in which target material is deposited on the surface surrounding the drain 310, i.e., the opening of the drain 310, some of which can be sprayed back into the airflow that carries it back into the interior space of the chamber 326 and then towards and out of the central focus.

[0069] Figure 8A A view from inside the exhaust chamber 300 shows a drain 310 passing through an aperture or drain inlet throat 320 in a portion of the wall 305 of the exhaust chamber 300. The surface surrounding the drain 310 includes a drain edge 330 that meets the drain inlet rear wall 340. At the point where the drain edge 330 meets the drain inlet rear wall 340, there is a target material accumulation site 350.

[0070] Figure 8B yes Figure 8A A side view of the arrangement shows that the exhaust chamber 300 extends from the liner 329. The exhaust chamber 300 has a drain inlet throat 320 that leads to a cavity discharged by a drain 310 surrounded by a drain edge 330. A target material accumulation position 350 is formed at the junction of the drain edge 330 and the drain inlet rear wall 340.

[0071] According to one aspect of the embodiment, by placing a drain shield at the target material accumulation location 350, the target material accumulated at the target material accumulation location 350 is prevented from returning to the gas flowing through the exhaust chamber 300. The shield is arranged such that it captures target material splashed from the target material accumulation location without interfering with the flow of liquid target material into the drain 310. Furthermore, in some embodiments, the shield may be arranged to capture target material discharged into the drain orifice and splashed back due to impact with the drain channel wall. In some embodiments, the shield may also be arranged to dynamically capture target material, i.e., capture target material splashed during target material drainage, rather than just statically accumulated tin. In some embodiments, the shield may also be arranged to capture target material dripping from its surface into the drain channel above, or otherwise splashing upwards onto the source container. Similar to the shield described above, the surface of the shield may have engineered target material wetting properties to minimize the actual number and volume of target material particles moving toward the central focus.

[0072] This configuration is in Figure 9A It is shown in the middle, Figure 9A From and Figure 8A The same perspective is formed. The depicted features and combinations Figure 8A The features described are the same, except that the drain shield 360 has been positioned above the target material accumulation position 350 and spaced apart from the drain 310. Figure 9B yes Figure 9AThe side view of the arrangement includes a drain shield 360. In some embodiments, the drain shield 360 has a U-shaped or V-shaped cross-sectional view, the drain shield 360 and... Figure 4B The shielding element 170 is similar. As in the case of the shielding element in the foregoing embodiments, the body or main body of the drain shielding element 360 can be made of materials such as molybdenum, molybdenum alloy, or stainless steel. Where a tin-affinity surface is desired, the body or main body of the drain shielding element 360 can be coated with materials such as titanium nitride or tin.

[0073] In the illustrated embodiment, the drain shield 360 is a substantially planar element, but the drain shield 360 can have different shapes, as long as it performs the function of preventing the ejected target material from re-entering the airflow. In some embodiments, the upper edge of the drain shield 360 is arc-shaped (i.e., concave upwards or downwards) so that the molten target material on the drain inlet rear wall 340 can flow to the drain 310, such as... Figure 10 As shown in the image. In this case, from the side view... Figure 9B The drain shield 360 is separate from the drain inlet rear wall 340. Only the two ends of the upper edge of the drain shield 360 are connected to the drain inlet rear wall 340. In some embodiments, the lower edge of the drain shield 360 is arc-shaped (i.e., concave upwards or downwards) to substantially align the corresponding edge of the drain inlet throat 320, such as... Figure 10 As shown.

[0074] In some embodiments, the drain shield 360 may be oriented at an angle relative to gravity, for example, in the range of approximately +100° to -100°. A smaller angle relative to gravity can open a line-of-sight path from the target material accumulation site 350 to the intermediate focal point. A larger angle can begin to constrain the flow of target material toward the drain 310. In some embodiments, the shield is tilted at least 20° relative to the horizontal plane to prevent target material from accumulating on the shield itself. The thickness of the drain shield 360 is, for example, in the range of approximately 1 mm to 8 mm. A drain shield 360 with a thickness less than this range may lack sufficient rigidity, while a thickness greater than this range does not provide additional advantages in terms of the required mechanical strength. The drain shield 360 may be attached to a wall extending upward from around the drain 310, for example, by attachment using any suitable method.

[0075] In the example of using tin as the target material, the area surrounding the drain element can also be made of molybdenum or a molybdenum alloy or stainless steel and coated with a titanium nitride coating, which acts as a barrier layer between the underlying host material structure and the liquid target material. This titanium nitride coating is highly tin-repellent, meaning that liquid tin forms droplets on the surface rather than depositing as a thin layer. In contrast, tin plating on a stainless steel surface creates a tin-affinity surface where tin is deposited as a thin layer spreading over a larger surface area. This produces far less tin sputtering with smaller particles that are less likely to be transported across the intermediate focusing aperture. Therefore, in the context of this example, the sputtering barrier can preferably be made of stainless steel coated with a thin tin coating. The combination of a titanium nitride-coated drain element and a separate tin-coated sputtering barrier can yield an optimized combination of service life and performance.

[0076] In some embodiments, the upper and / or lower edges of the shield may be curved in a concave (curve above the tangent) manner. Figure 11 The arrangement of the shield 370, wherein both the upper curved edge 372 and the lower curved edge 374 are shown. Furthermore, the shield can have a 3D configuration, rather than using a shield with a substantially flat 2D configuration. For example, Figure 12 The diagram shows that the shield 380 has a hairpin (V or U) shaped arrangement as described above in conjunction with the washer shield. Those skilled in the art who have been provided with this disclosure will understand that other configurations are also possible.

[0077] As previously described, IC fabrication can be achieved by providing a substrate having a surface with a photoresist layer, and directing radiation from a radiation source to the surface with the photoresist layer to transfer a pattern from a mask onto the photoresist layer, the radiation source including one or more features of the above embodiments, or implementing the described method, or both, and then removing a portion of the photoresist layer to form a pattern on the substrate. While specific references may be made herein to the application of photolithography apparatus in integrated circuit fabrication, it should be understood that the photolithography apparatus described herein may have other uses. Other possible applications include, for example, the fabrication of integrated optical systems, the guiding and detection of patterns in magnetic domain memories, flat panel displays, liquid crystal displays (LCDs), thin-film magnetic heads, etc.

[0078] Some of the above descriptions are in the form of functional block diagrams, where some functions are assigned to some boxes and others to other boxes. It should be understood that the division between boxes and between assignments is arbitrary, and different divisions and assignments are possible as long as the overall functionality is implemented as described above.

[0079] The above description includes examples of multiple embodiments. It is certainly impossible to describe all conceivable combinations of components or methods for each of these embodiments; however, those skilled in the art will recognize that further combinations and arrangements of elements from various embodiments are possible based on this disclosure. Therefore, the described embodiments are intended to represent and cover all such changes, modifications, and variations falling within the spirit and scope of the appended claims.

[0080] Furthermore, to some extent, the term "comprising" is used in the specific embodiments or claims, and this term is intended to be inclusive, in a manner similar to how the term "comprising" is interpreted when used as a transitional word in the claims. Additionally, although elements of the described aspects and / or embodiments may be described or claimed in the singular, the plural form is also considered unless explicitly stated otherwise. Furthermore, unless otherwise stated, all or part of any aspect and / or embodiment may be used in combination with all or part of any other aspect and / or embodiment.

[0081] The features, materials, properties, or groups described in connection with particular aspects, embodiments, or examples should be understood to be applicable to any other aspect, embodiment, or example described in this section or other parts of this specification, unless incompatible with them. All features disclosed in this specification (including any appended claims, abstract, and drawings) can be combined in any combination, except for combinations where at least some features and / or steps are mutually exclusive. Protection is not limited to the details of any of the foregoing embodiments. Protection extends to any feature or any novel combination thereof disclosed in this specification (including any appended claims, abstract, and drawings), or to any novel step or any novel combination thereof of any method or process as disclosed.

[0082] Furthermore, in the context of individual implementations, certain features described herein may also be implemented in combination in a single implementation. Conversely, the various features described in the context of a single implementation may also be implemented individually in multiple implementations, or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations, in some cases, one or more features from a claimed combination may be removed from that combination, and that combination may be claimed as a sub-combination or a variation thereof.

[0083] Furthermore, although the operations may be depicted in a particular order in the accompanying drawings or described in a particular order in this specification, these operations need not be performed in the particular order or sequential order shown, or all operations need to be performed, to achieve the desired result. Other operations not depicted or described may be included in the example method and process. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the described operations. Moreover, these operations may be rearranged or reordered in other embodiments. Those skilled in the art will understand that in some embodiments, the actual steps taken in the illustrated and / or disclosed process may differ from those shown in the figures. According to embodiments, some of the above steps may be removed, and others may be added.

[0084] Furthermore, the features and attributes of the specific embodiments disclosed above can be combined in different ways to form additional embodiments, all of which fall within the scope of this disclosure. Similarly, the separation of various system components in the above embodiments should not be construed as requiring such separation in all embodiments, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged in multiple products.

[0085] For the purposes of this disclosure, certain aspects, advantages, and novel features have been described herein. Not all of these advantages may be realized according to any particular embodiment. Therefore, for example, those skilled in the art will recognize that this disclosure may be implemented or performed in a manner that achieves one or a set of advantages taught herein, without necessarily achieving other advantages that may be taught or suggested herein.

[0086] Unless otherwise expressly stated or understood in the context in which they are used, conditional language such as “can,” “may,” “perhaps,” or “may” is intended to convey that certain features, elements, and / or steps are included in some embodiments but not in others. Therefore, such conditional language is generally not intended to imply that these features, elements, and / or steps are necessary in any way for one or more embodiments, nor is it intended to imply that one or more embodiments necessarily include logic executed, regardless of user input or prompting, for determining whether such features, elements, and / or steps are included in any particular embodiment.

[0087] Connective language such as the phrase “at least one of X, Y, and Z” is generally understood, in the context in which it is used, to mean that the item, aspect, etc., can be X, Y, or Z. Therefore, such connective language is not generally intended to imply that some embodiments require at least one X, at least one Y, and at least one Z.

[0088] Terms such as “about,” “approximately,” “generally,” and “basically,” as used herein, refer to a value, quantity, or characteristic that is close to the stated value, quantity, or characteristic while still performing the desired function or achieving the desired result. For example, the terms “about,” “approximately,” “generally,” and “basically” may refer to a quantity that is less than 10%, 5%, 1%, 0.1%, or 0.01% of the stated quantity. As another example, in some embodiments, the terms “approximately parallel” and “basically parallel” refer to a value, quantity, or characteristic that deviates from exact parallelism by less than or equal to 15 degrees, 10 degrees, 5 degrees, 3 degrees, 1 degree, or 0.1 degrees.

[0089] The scope of this disclosure is not intended to be limited to the specific disclosure of preferred embodiments in this section or other parts of this specification, and may be defined by the claims presented or to be presented in this section or other parts of this specification. The language of the claims should be interpreted broadly based on the language used in the claims and is not limited to the examples described in this specification or during the examination of this application, which should be interpreted as non-exclusive.

[0090] The aspects and embodiments of this disclosure may be further described using the following reference numerals: 1. An apparatus for generating extreme ultraviolet radiation by irradiating a target material, the apparatus comprising: a source container; a target material deposition surface arranged to receive deposited target material from an airflow as the airflow passes through the target material deposition surface; a drain in fluid communication with the target material deposition surface, the drain including a drain opening and an edge surface adjacent to the drain opening; and a shield covering at least a portion of the edge surface and positioned to prevent target material from being ejected back into the airflow. 2. The apparatus according to Clause 1, wherein the target material deposition surface is coupled to the surface of the scrubber. 3. The apparatus according to Clause 2, wherein the surface of the washer includes a plurality of fin structures. 4. The apparatus according to Clause 1, wherein the shielding element comprises molybdenum. 5. The device according to Clause 1, wherein the thickness of the shield is in the range of about 1 mm to about 8 mm. 6. The device according to Clause 1, wherein the shielding element comprises a titanium-zirconium-molybdenum alloy. 7. The device according to Clause 1, wherein the shielding comprises stainless steel. 8. The apparatus according to Clause 1, wherein the target material comprises tin, and wherein at least a portion of the surface of the shield is provided with a layer comprising a tin-affinity material. 9. The device according to Clause 1, wherein the upper edge of the shield is curved. 10. The apparatus according to Clause 2, wherein the shield has an upper surface and a side surface, wherein the upper surface is at an angle to the side surface, and wherein the shield is oriented in the scrubber such that the upper surface is at an angle relative to gravity in the range of about 0° to about 45°, and the side surface is a plasma-facing surface having an angle relative to gravity in the range of about 20° to about 70°. 11. The apparatus according to Clause 1, wherein the target material deposition surface includes the surface of the exhaust chamber. 12. The apparatus according to Clause 11, wherein the shield is a substantially planar element that extends over and is spaced apart from the drain opening and is inclined relative to a horizontal plane. 13. A target material scrubber for an apparatus that generates extreme ultraviolet radiation by irradiating a target material, the target material scrubber comprising: Multiple target material deposition surfaces are arranged such that a gas carrying target material passes through the target material deposition surfaces, thereby transferring the target material from the gas to the target material deposition surfaces. A drain element, positioned such that target material transferred to the target material deposition surface flows to the drain element, the drain element having an edge region, and A shielding element is positioned above at least a portion of the edge region of the draining element to prevent the target material from being ejected back into the gas. 14. The target material scrubber according to Clause 13, wherein the scrubber is coupled to the plasma generation space of the radiation source. 15. The target material scrubber according to Clause 14, wherein the shield is positioned between the scrubber and the plasma generation space of the radiation source. 16. An apparatus for generating extreme ultraviolet radiation by irradiating target material, the apparatus comprising: a chamber; a waste target material management system disposed within the chamber and configured to discharge a gas carrying stray target material, the waste target material management system including at least one location where liquid waste target material accumulates during operation of the apparatus; and a shield disposed over at least a portion of the at least one location where liquid waste target material accumulates during operation of the apparatus to prevent waste target material from being ejected back into the gas. 17. A method of manufacturing a semiconductor device, comprising providing a substrate having a surface with a photoresist layer, directing radiation from a radiation source to the surface with the photoresist layer, the radiation source including a source chamber, a waste target material management system disposed within the source chamber and configured to discharge a gas carrying stray target material, the waste target material management system including at least one location where liquid waste target material accumulates when the radiation source is in operation, and a shield disposed over at least a portion of the at least one location where liquid waste target material accumulates when the radiation source is in operation to prevent waste target material from being ejected back into the gas, thereby transferring a pattern from a mask onto the photoresist layer; and removing a portion of the photoresist layer to form a pattern on the substrate. 18. The method of claim 17, wherein the waste target material management system surrounds the source container. 19. The method of claim 17, wherein the waste target material management system comprises a plurality of fins arranged around the interior of the source container.

[0091] The above aspects, embodiments, and other embodiments are within the scope of the following claims.

Claims

1. An apparatus for generating extreme ultraviolet radiation, the apparatus comprising: Source container; A target material deposition surface is arranged to receive the deposited target material from the airflow as the airflow passes through the target material deposition surface; A draining device is in fluid communication with the target material deposition surface, the draining device including a draining device opening and an edge surface adjacent to the draining device opening; as well as A shielding element that covers at least a portion of the edge surface.

2. The apparatus of claim 1, wherein the target material deposition surface is coupled to the surface of the scrubber.

3. The apparatus of claim 2, wherein the washer comprises a plurality of fin structures.

4. The apparatus of claim 1, wherein the shield is configured to prevent the target material from being ejected back into the airflow.

5. The apparatus of claim 1, wherein the thickness of the shield is in the range of about 1 mm to about 8 mm.

6. The device according to claim 1, wherein the shielding element comprises at least one of the following materials: titanium, zirconium, and molybdenum.

7. The apparatus of claim 1, wherein the shielding element comprises stainless steel.

8. The apparatus of claim 1, wherein the target material comprises tin, and wherein at least a portion of the surface of the shield is provided with a layer comprising a tin-affinity material.

9. The device according to claim 1, wherein the upper edge of the shield is curved.

10. The apparatus of claim 2, wherein the shield has an upper surface and a side surface, wherein the upper surface is at an angle to the side surface, and wherein the shield is oriented in the scrubber such that the upper surface is at an angle relative to gravity in the range of about 0° to about 45°, and the side surface is a plasma-facing surface having an angle relative to gravity in the range of about 20° to about 70°.

11. The apparatus of claim 1, wherein the target material deposition surface includes the surface of the exhaust chamber.

12. The apparatus of claim 11, wherein the shield is a substantially planar element that extends over and is spaced apart from the drain opening and is inclined relative to a horizontal plane.

13. A scrubber for a radiation source, comprising: Multiple target material deposition surfaces are arranged such that a gas carrying target material passes through the target material deposition surfaces, thereby transferring the target material from the gas to the target material deposition surfaces. as well as A shielding element configured to prevent target material from being ejected back into the gas.

14. The scrubber of claim 13, further comprising a drain, the drain being positioned such that the target material transferred to the target material deposition surface flows to the drain.

15. The washer of claim 14, wherein the drain member has an edge region, and the shield is positioned on at least a portion of the edge region.

16. The washer of claim 13, wherein the washer is coupled to the plasma generation space of the radiation source.

17. The washer of claim 16, wherein the shielding is positioned between the washer and the plasma generation space of the radiation source.

18. A method for manufacturing a semiconductor device, comprising: Provide a substrate having a surface with a photoresist layer; Radiation is directed from the radiation source to the surface with a photoresist layer. The radiation source includes: a source container; a waste target material management system disposed within the source container and configured to discharge gas carrying stray target material; the waste target material handling system includes at least one location where liquid waste target material accumulates when the radiation source is operating, and a shield disposed above at least a portion of the at least one location where liquid waste target material accumulates when the radiation source is operating, to prevent waste target material from being ejected back into the gas. as well as A portion of the photoresist layer is removed to form a pattern on the substrate.

19. The method of claim 18, wherein the waste target material management system surrounds the source container.

20. The method of claim 18, wherein the waste target material management system comprises a plurality of fins arranged around the interior of the source container.

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