Cleaning apparatus, exposure apparatus, cleaning method, and method of manufacturing article

Abstract

To provide a device advantageous for cleaning an optical element arranged closest to an image side among a plurality of optical elements included in an optical system.SOLUTION: A cleaning device that cleans an image-side surface of a first optical element disposed closest to an image side among a plurality of optical elements included in an optical system, the cleaning device including a first member that forms a first space in a region on the image side of the first optical element and separates the first space from a space closer to the image side than the first space, and a gas supply unit that supplies gas to the first space, in which the gas supply unit supplies the gas when light passing through the optical system is irradiated to the first space.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a cleaning apparatus, an exposure apparatus, a cleaning method, and a method for manufacturing an article. [Background technology]

[0002] Exposure apparatuses used in the manufacturing process of semiconductor devices, liquid crystal display devices, etc., have an optical system including multiple optical elements. Of these multiple optical elements, the optical element located closest to the image side may become cloudy due to contaminants. Patent Document 1 discloses a method of cleaning the optical element by placing a reflective member on the substrate stage and reflecting light with the reflective member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-164267 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the method of Patent Document 1, there is a possibility that contaminants around the optical element may undergo a chemical reaction due to light energy and adhere to the optical element, and the optical element cannot be cleaned sufficiently.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an apparatus that is advantageous for cleaning the optical element that is arranged closest to the image side among a plurality of optical elements included in an optical system. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, one aspect of the present invention provides a cleaning device that cleans the image-side surface of a first optical element that is arranged closest to the image side among a plurality of optical elements included in an optical system, and includes: a first member that forms a first space in an image-side region of the first optical element and separates the first space from a space that is further to the image side than the first space; and a gas supply unit that supplies gas to the first space, wherein the gas supply unit supplies the gas when light passing through the optical system is irradiated onto the first space.

[0007] Further objects and other aspects of the present invention will become apparent from the following description of the embodiments with reference to the drawings. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an apparatus that is advantageous for cleaning the optical element that is arranged closest to the image side among a plurality of optical elements included in an optical system. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of an exposure apparatus in a first embodiment. [Figure 2] FIG. 4 is a schematic diagram illustrating a cleaning operation in the first embodiment. [Figure 3] FIG. 3 is a flowchart illustrating a cleaning method according to the first embodiment. [Figure 4] FIG. 2 is a diagram of a rectifying member as viewed from the optical axis direction of the projection optical system. [Figure 5] 10A and 10B are schematic diagrams illustrating another example of a cleaning operation according to the first embodiment. [Figure 6] In this example, the density of the flow passages through which the first gas flows in the central portion of the flow straightening member is higher than the density of the flow passages through which the first gas flows in the peripheral portion. [Figure 7] In this example, the density of the flow passages through which the first gas flows in the central portion of the flow straightening member is lower than the density of the flow passages through which the first gas flows in the peripheral portion. [Figure 8]In this example, the resistance of the flow path through which the first gas flows in the central part of the rectifying member is smaller than the resistance of the flow path through which the first gas flows in the peripheral part of the rectifying member. [Figure 9] In this example, the resistance of the flow path through which the first gas flows in the peripheral portion of the rectifying member is smaller than the resistance of the flow path through which the first gas flows in the central portion of the rectifying member. [Figure 10] FIG. 10 is a flowchart showing a method for manufacturing an article according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and the embodiments may be combined in any manner. Furthermore, in the drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0011] In addition, in this specification and drawings, directions are basically indicated by an XYZ coordinate system in which the vertical direction is the Z-axis direction and the horizontal plane perpendicular to the vertical direction is the XY plane, with each axis being orthogonal to each other. However, if an XYZ coordinate system is shown in each drawing, that coordinate system takes precedence.

[0012] Specific configurations of each embodiment will be described below.

[0013] First Embodiment 1 is a schematic diagram showing the configuration of an exposure apparatus 200 in this embodiment. In this embodiment, exposure apparatus 200 is a projection exposure apparatus that exposes a pattern of an original (mask, reticle) onto a substrate via a projection optical system using a step-and-repeat method or a step-and-scan method.

[0014] The exposure apparatus 200 includes an illumination optical system 201 that irradiates light, a projection optical system 2, a reticle stage 203 that holds a reticle 202, a substrate stage 205 that holds a substrate 204, a control unit 206, a measurement unit 207, and an air conditioning unit 208. The reticle 202 is, for example, an original in which a pattern to be transferred (e.g., a circuit pattern) is formed on the surface of quartz glass using chromium. The substrate 204 is, for example, single-crystal silicon, and has a photosensitive material (resist) applied to its surface. The control unit 206 controls each component of the exposure apparatus 200.

[0015] The control unit 206 includes a processing unit, a bus, a ROM, a RAM, and a storage device, and each component functions according to a program. The processing unit is a processing device that performs control calculations according to the program and controls each component connected to the bus. This processing unit can be configured using a CPU, a PLD such as an FPGA, an ASIC, a computer with a built-in program, or a combination of all or part of these. The ROM is a memory for reading data only and stores programs and data. The RAM is a memory for reading and writing data and is used to store programs and data. The RAM is used for temporary storage of data such as the results of CPU calculations. The storage device is also used to store programs and data. The storage device is also used as a temporary storage area for the operating system (OS) program and data of the control unit 206. The storage device has slower data input / output speeds than RAM, but is capable of storing large amounts of data. The storage device is preferably a non-volatile storage device that can store data as permanent data so that the data can be referenced for a long period of time. The storage device is mainly composed of a magnetic storage device (HDD), but may also be a device that reads and writes data by loading external media such as CDs, DVDs, and memory cards.

[0016] The air conditioning unit 208 includes a conditioned gas supply unit 209 and a chemical filter 210. The conditioned gas 211 supplied from the conditioned gas supply unit 209 passes through the chemical filter 210, where impurities (acids, bases, organic compounds, etc.) are removed. The conditioned gas 211 from which the impurities have been removed is supplied to the space between the projection optical system 2 and the substrate 204. The exposure apparatus 200 further includes a gas supply unit 30, and a drive unit 101 that includes a hand 102 and transports the first member 100. The gas supply unit 30, the drive unit 101 that includes the hand 102, and the first member 100 will be described later.

[0017] In the exposure apparatus 200, exposure light from a light source (not shown) passes through an illumination optical system 201 and illuminates a reticle 202 held on a reticle stage 203. The light that passes through the reticle 202 passes through a projection optical system 2 and is irradiated onto a substrate 204. At this time, light from a pattern formed on the reticle 202 forms an image on the surface of the substrate 204, and a shot area on the substrate 204 (photosensitive material) is exposed to the pattern image. The exposure apparatus 200 exposes the shot area on the substrate 204 in this manner, and performs exposure on each of the multiple shot areas in the same manner. During exposure, the measurement unit 207 measures a mark (alignment mark) on at least one of the substrate 204 and the substrate stage 205, and based on the measurement result, the substrate stage 205 is driven to align the substrate 204 to the desired position.

[0018] In an optical system including multiple optical elements, such as the projection optical system 2, the first optical element 3, which is the optical element closest to the image, may become cloudy due to contaminants. Contaminants may originate from the photosensitive material (resist) on the substrate, the grease and adhesive used in the drive system and structures, and components made of resin or rubber. The contaminants generated from these sources are carried by the air conditioning gas 211 to the space between the substrate 204 and the optical element closest to the image, where they react with impurities such as acids, bases, and organic matter in the atmosphere surrounding the first optical element 3, as well as with a film on the surface of the first optical element 3, causing the first optical element 3 to become cloudy. Clouding of the first optical element 3 can result in insufficient exposure, uneven illuminance, flare, and other problems, resulting in reduced exposure accuracy.

[0019] To prevent this fogging, one possible method is to utilize conditioned gas 211 to prevent impurities from being contained in the atmosphere surrounding first optical element 3. However, chemical filter 210 deteriorates with use, and therefore may not be able to sufficiently remove impurities from conditioned gas 211. Furthermore, when the source of conditioned gas 211 from air conditioning unit 208 is the air of the clean room in which exposure apparatus 200 is located, the cleanliness of conditioned gas 211 depends on the cleanliness of the clean room. In other words, if the cleanliness of the clean room is low, the rate of deterioration of chemical filter 210 will increase, and the amount of impurities contained in conditioned gas 211 cannot be reduced unless chemical filter 210 is replaced frequently.

[0020] When the first optical element 3 becomes cloudy, one method is to replace the first optical element 3 with a new optical element. However, this method is costly and requires production to be stopped for replacement, which reduces productivity.

[0021] Another method, as described in Patent Document 1, involves placing a reflective member on the substrate stage and reflecting light off the reflective member to clean the first optical element 3. This method primarily utilizes three methods to clean the first optical element 3. The first method uses light to convert oxygen molecules around the first optical element 3 into ozone, which then chemically reacts with contaminants adhering to the surface of the first optical element 3, resulting in gaseous substances such as H2O and CO2, which are then emitted. The second method uses light energy to physically blow away the contaminants adhering to the surface of the first optical element 3. The third method uses light to separate the bonds of molecules contained in the contaminants, resulting in molecules with a small mass number, which no longer qualify as contaminants. However, the method described in Patent Document 1 may chemically react with the light energy to contaminants around the first optical element 3, resulting in adhesion to the optical element, making it difficult to adequately clean the optical element. Even if the air conditioning unit 208 is applied to the method of Patent Document 1 to reduce the amount of contaminants around the first optical element 3 and reduce adhesion of contaminants to the optical element, the ozone generated by the air conditioning gas 211 flows rather than remaining near the first optical element 3. This makes it impossible to sufficiently clean the first optical element 3.

[0022] Another possible method is to remove the first optical element 3 from the projection optical system 2 and clean the first optical element 3 in a cleaning room where cleanliness is guaranteed, but this method takes time to attach and detach the first optical element 3. Furthermore, a separate cleaning room must be prepared, which adds to costs.

[0023] Therefore, this embodiment provides an apparatus that is advantageous for cleaning the first optical element 3, which is arranged closest to the image side among the multiple optical elements included in the projection optical system 2. Specifically, when cleaning the first optical element 3, a first member 100 that forms a first space is placed in the image-side region of the first optical element 3. Then, when light via the projection optical system 2 is irradiated onto the first space, gas is supplied to the first space. This makes it possible to effectively remove fogging from the first optical element by using ozone generated in the first space, while the amount of impurities and contaminants around the first optical element 3 is reduced.

[0024] Fig. 2 is a schematic diagram of the cleaning operation in this embodiment, and is a cross-sectional view of the cleaning device including the gas supply unit 30 and the first member 100. Fig. 3 is a flowchart of the cleaning method in this embodiment. The cleaning operation in this embodiment will be described with reference to Figs. 2 and 3.

[0025] First, when cleaning the first optical element 3, the first member 100 is placed in an area on the image side of the first optical element 3 (placement step, S110). Specifically, the hand 102 of the drive unit 101 shown in FIG. 1 holds the first member 100 placed at a predetermined position. Then, the drive unit 101 transports the first member 100 held by the hand 102 to an area on the image side of the first optical element 3, and the hand 102 maintains a state in which the first member 100 is held at a predetermined position on the image side of the first optical element 3. During the cleaning operation, the hand 102 continues to maintain a state in which the first member 100 is held at a predetermined position on the image side of the first optical element 3. Note that the cleaning operation is not limited to the example in which the hand 102 holds the first member 100 at a predetermined position on the image side of the first optical element 3, and the first member 100 may be attached to the projection optical system 2 by the drive unit 101 or another mechanism. In this case, in the placement process of step S110, the first member 100 is attached to the projection optical system 2. The first member 100 may also be placed so that the gas outlet of the gas supply unit 30 is located within the first space 103 formed by the first member 100.

[0026] Next, the gas supply unit 30 supplies the first gas 41 to the first space 103 (second space 104) (supply step, S120). The gas supply unit 30 includes a gas supply source 31, an adjustment unit 32, and a blowout unit 33. The flow rate of the first gas 41 supplied from the gas supply source 31 is adjusted by the adjustment unit 32, and the first gas 41 is blown out from the blowout unit 33 into the first space 103 (second space 104) formed on the image side of the first optical element 3 by the first member 100. The first gas 41 is, for example, a gas obtained by mixing oxygen with clean dry air or nitrogen gas, and may be any gas containing oxygen with a small amount of impurities and pollutants.

[0027] The first member 100 includes a base portion 106 and rectifying members 107 and 108. The base portion 106 is a member for forming the first space 103 in an area on the image side of the first optical element 3. In other words, the base portion 106 is a member for forming the first space 103 with few impurities and contaminants and for enclosing the first gas 41 supplied from the gas supply unit 30 during a cleaning operation of the first optical element 3. In other words, the first member 100 is a member for separating the first space 103 on the image side of the projection optical system 2, to which the first gas 41 is supplied from the gas supply unit 30, from a space further to the image side than the first space 103. The rectifying member 107 (second member) is a member for dividing the first space 103 into a second space 104 and a third space 105, and the rectifying member 107 includes a structure that allows the first gas 41 to flow from the second space 104 to the third space 105 via the rectifying member 107. The flow rectifying member 108 is a member for diffusing the first gas 41 supplied from the gas supply unit 30 into the first space 103 (second space 104).

[0028] During the cleaning operation, exposure light is irradiated onto the first space 103 via the projection optical system 2. At this time, the gas supply unit 3 supplies the first gas 41 toward the first space 103 (second space 104). The supplied first gas 41 spreads into the second space 104 via the rectifying member 108 while its flow velocity decreases. Because the first gas 41 is a gas containing oxygen, the exposure light causes the first gas 41 to contain ozone, which has a cleaning effect.

[0029] The first gas 41 in the second space 104 flows into the third space 105 via the rectifying member 107. The first gas 41 spreads generally uniformly within the third space 105 by passing through the rectifying member 107. Note that ozone is also generated in the third space 105 by the exposure light, increasing the concentration of ozone contained in the first gas 41. Because the first gas 41 passes through the rectifying member 107 when flowing into the third space 105, it is sprayed generally uniformly onto the effective irradiation area (the area from which the exposure light is emitted) of the first optical element 3. When this ozone-containing first gas 41 is sprayed onto the effective irradiation area of ​​the first optical element 3, the ozone chemically reacts with contaminants adhering to the surface of the first optical element 3, converting the contaminants into gaseous substances such as H2O and CO2. This removes fogging from the first optical element 3. The first gas 41 is then discharged through the opening 42.

[0030] After the cleaning operation is completed, the first member 100 is retracted by the driving unit 101 (retraction step, S130). Note that if the first member 100 is attached to the projection optical system 2 in step S110, the first member 100 is removed from the projection optical system 2 in step S130.

[0031] The opening 42 may be provided so that the first gas 41 is discharged from a portion of the base portion 106, or so that the first gas 41 is discharged from a plurality of positions on the base portion 106, and its shape is not particularly limited. Note that, by making the inside of the first space 103 under a more positive pressure than the outside, it is possible to prevent the inflow of gas containing impurities and pollutants from the outside, so it is advisable to determine the shape and arrangement of the opening 42 so that the inside of the first space 103 under a more positive pressure than the outside.

[0032] The area of ​​the surface of the first member 100 facing the first optical element 3 (the surface of the base portion 106 facing the first optical element 3) is preferably larger than the area of ​​the effective irradiation region on the image-side surface of the first optical element 3. Furthermore, the area of ​​the surface of the rectifying member 107 facing the first optical element 3 is preferably larger than the area of ​​the effective irradiation region of the first optical element 3. In this way, the cleaning effect of the first gas 41 can be imparted to the entire effective irradiation region of the first optical element 3.

[0033] In the cleaning operation of this embodiment, not only cleaning with ozone is performed, but also cleaning by using light energy to physically blow away contaminants adhering to the surface of the first optical element 3. Furthermore, cleaning by using light to change molecules contained in the contaminants into molecules with a small mass number is also performed at the same time.

[0034] Next, the shape of the rectifying member 107 will be described. The rectifying member 107 includes at least one of a porous structure such as a sintered body, a structure including multiple tubes, a lattice-like structure, and a structure with multiple holes. FIG. 4 is a view of the rectifying member 107 as viewed from the optical axis direction of the projection optical system 2. FIG. 4(a) shows an example in which the rectifying member 107 includes a porous structure such as a sintered body. The first gas 41 flows from the second space 104 to the third space 105 through the holes 107a of the porous structure. FIG. 4(b) shows an example in which the rectifying member 107 includes multiple tubes 107b. The first gas 41 flows from the second space 104 to the third space 105 through the tubes 107b. FIG. 4(c) shows an example in which the rectifying member 107 includes a lattice-like structure. The first gas 41 flows from the second space 104 to the third space 105 through the spaces 107c between the lattices. 4(d) shows an example in which a plurality of holes 107d are provided in the rectifying member 107. The first gas 41 flows from the second space 104 to the third space 105 through the plurality of holes 107d. The structure of the rectifying member 107 is not limited to the above example, and may be any structure as long as it allows the first gas 41 to flow from the second space 104 to the third space 105. Furthermore, a single rectifying member 107 may include a plurality of structures.

[0035] The rectifying member 107 is preferably transparent so that more of the exposure light can reach the second space 104. By allowing more of the exposure light to reach the second space 104, the amount of ozone generated can be increased. Furthermore, the surface of the base portion 106 facing the first optical element 3 preferably has a high reflectivity, and is preferably, for example, a surface including a reflective member or a silver surface. This allows ozone to be generated even by reflected light, thereby increasing the amount of ozone generated.

[0036] In this embodiment, it is preferable that the first gas 41 is blown approximately uniformly onto the effective irradiation area of ​​the first optical element 3 via the rectifying member 107. Therefore, in a plane (XY plane) perpendicular to the optical axis of the projection optical system 2, it is preferable that the density of the flow path through which the first gas 41 flows in the center of the rectifying member 107 is approximately the same as the density of the flow path through which the first gas 41 flows in the peripheral part of the rectifying member 107. It is more preferable that the density of the flow path through which the first gas 41 flows in the center of the rectifying member 107 is the same as the density of the flow path through which the first gas 41 flows in the peripheral part of the rectifying member 107. Here, the flow path through which the first gas 41 flows in the center of the rectifying member 107 refers to the flow path corresponding to the center of the effective irradiation area of ​​the first optical element 3. Furthermore, the flow path through which the first gas 41 flows in the peripheral part of the rectifying member 107 refers to the flow path corresponding to the peripheral part of the effective irradiation area of ​​the first optical element 3. It should be noted that the central part of the effective irradiation area of ​​the first optical element 3 in this embodiment refers to, for example, a range having a diameter from the optical axis of the first optical element 3 that is equal to or less than half the diameter of the effective irradiation area of ​​the first optical element 3. Alternatively, the central part of the effective irradiation area of ​​the first optical element 3 refers to, for example, a range having a diameter from the optical axis of the first optical element 3 that is equal to or less than one-third the diameter of the effective irradiation area of ​​the first optical element 3. Furthermore, the peripheral part of the effective irradiation area of ​​the first optical element 3 refers to a range of the effective irradiation area of ​​the first optical element 3 that does not include the central part.

[0037] The density of the flow paths can be found, for example, by dividing the area of ​​the flow paths within a target region in a certain cross section by the area of ​​the target region. Specifically, the density of the flow paths through which the first gas 41 flows in the center of the flow rectifying member 107 can be found by dividing the area of ​​the flow paths through which the first gas 41 flows in the center of the flow rectifying member 107 in a given cross section by the area of ​​the center of the flow rectifying member 107. Furthermore, the density of the flow paths through which the first gas 41 flows in the peripheral parts of the flow rectifying member 107 can be found by dividing the area of ​​the flow paths through which the first gas 41 flows in the peripheral parts of the flow rectifying member 107 in a given cross section by the area of ​​the peripheral parts of the flow rectifying member 107.

[0038] Furthermore, the amount of first gas 41 blown onto the first optical element 3 per unit time varies depending on the resistance in the flow path. Specifically, the longer the length of the flow path (the thicker the rectifying member 107) and the smaller the area of ​​each flow path, the more difficult it is for the first gas 41 to flow from the second space 104 to the third space 105, and the greater the resistance. In this embodiment, it is preferable that the first gas 41 be blown approximately uniformly onto the effective irradiation area of ​​the first optical element 3 by passing through the rectifying member 107. Therefore, it is preferable that the resistance of the flow path through which the first gas 41 flows in the center of the rectifying member 107 is approximately the same as the resistance of the flow path through which the first gas 41 flows in the peripheral part of the rectifying member 107. It is even more preferable that the resistance of the flow path through which the first gas 41 flows in the center of the rectifying member 107 is the same as the resistance of the flow path through which the first gas 41 flows in the peripheral part of the rectifying member 107.

[0039] In this embodiment, an example has been shown in which first member 100 includes base portion 106 and rectifying members 107 and 108, but this is not limiting. Fig. 5 is another example of a schematic diagram showing a cleaning operation in this embodiment. For example, if first gas 41 can be sprayed generally uniformly over the effective irradiation area of ​​first optical element 3 without rectifying members 107 and 108, first member 100 does not need to include rectifying members 107 and 108 as shown in Fig. 5.

[0040] Next, the timing of performing the cleaning operation for the first optical element 3 will be described. For example, the control unit 206 may determine the fogging of the first optical element 3 based on the results of detection of the exposure dose, illuminance, and flare by a detection unit (not shown) and determine whether or not a cleaning operation is necessary. Alternatively, the cleaning operation of this embodiment, which removes fogging on the image-side surface of the first optical element 3, may be performed at the same timing as an aging process in which light is irradiated to remove fogging inside the optical system. Alternatively, the cleaning operation of this embodiment may be performed at a predetermined regular maintenance timing. Alternatively, the cleaning operation of this embodiment may be performed when a cleaning command is input by an operator. When performing the cleaning operation, the control unit 206 controls the gas supply unit 30, the drive unit 101, and the irradiation of exposure light.

[0041] In the present embodiment, an example has been described in which the first gas 41 in the first space 103 is discharged through the opening 42. However, a configuration in which a gas recovery mechanism is provided in the opening 42 to recover the gas may also be employed. Furthermore, in the present embodiment, an example has been described in which the gas supply unit 30 includes the adjustment unit 32. However, if it is not necessary to adjust the flow rate of the first gas 41 supplied from the gas supply unit 30, the adjustment unit 32 may not be included. Furthermore, in the present embodiment, an example has been described in which the light irradiated during the cleaning operation is exposure light. However, any light that can increase the amount of ozone contained in the first gas 41 may be used instead of exposure light. Furthermore, in the present embodiment, an example has been described in which the first member 100 is disposed in the image-side region of the first optical element 3 by the drive unit 101. However, the first member 100 may be attached by an operator.

[0042] In this embodiment, an example has been shown in which cleaning is performed on the first optical element 3 included in the projection optical system 2. However, the cleaning device of this embodiment may also be applied to cleaning the optical element arranged closest to the image side in the illumination optical system 201, or the optical element arranged closest to the image side in a measurement optical system included in the measurement unit 207, etc.

[0043] In this embodiment, the exposure apparatus 200 is a projection exposure apparatus, but the exposure apparatus 200 may be another lithography apparatus (substrate exposure apparatus). For example, the exposure apparatus 200 may be an imprint apparatus that uses a mold to shape an imprint material on a substrate to form a pattern on the substrate. Alternatively, the exposure apparatus 200 may be a planarization apparatus that uses a flat plate to planarize a composition on the substrate and cures the composition with light.

[0044] According to this embodiment, cleaning of the first optical element 3 can be easily performed without removing the first optical element 3 from the optical system by disposing the first member 100 and supplying gas from the gas supply unit 30 to the first space 103 within the first member 100. Furthermore, even when performing an exposure operation after a cleaning operation, the first member 100 can be retracted, allowing for immediate transition to the exposure operation. By using the cleaning device of this embodiment, there is no need to provide a dedicated cleaning chamber. Furthermore, because exposure light can be used for cleaning, there is no need to provide a light source control mechanism or the like for the cleaning operation. Furthermore, cleaning is performed by generating ozone from the first gas 41 supplied to the first space 103 within the first member 100, so cleaning can be performed with a reduced amount of impurities and contaminants. This reduces the possibility that contaminants around the optical element will chemically react with light energy and adhere to the optical element, thereby enabling the first optical element 3 to be thoroughly cleaned. Furthermore, because ozone is sprayed onto the first optical element 3 in the space enclosed by the first member 100, the ozone does not disperse into the surrounding area, allowing for effective cleaning in a short period of time. Furthermore, since the cleaning operation is not affected by the conditioned gas 211 from the air conditioning unit 208, there is no need to stop the supply of the conditioned gas 211, and the cleanliness of the space in which the exposure apparatus 200 is placed is not reduced.

[0045] Second Embodiment This embodiment differs from the first embodiment in the shape of the rectifying member 107. In the first embodiment, the first gas 41 was blown generally uniformly onto the effective irradiation area of ​​the first optical element 3 via the rectifying member 107. However, the first optical element 3 may not be uniformly clouded, and the central portion and peripheral portion of the first optical element 3 may be clouded differently. Therefore, this embodiment uses a rectifying member 107 that corresponds to the clouding state of the first optical element 3. Specifically, a rectifying member 107 is used in which the density of the flow path through which the first gas 41 flows in the central portion of the rectifying member 107 is different from the density of the flow path through which the first gas 41 flows in the peripheral portion of the rectifying member 107.

[0046] It should be noted that the central part of the effective irradiation area of ​​the first optical element 3 in this embodiment refers to, for example, a range having a diameter from the optical axis of the first optical element 3 that is equal to or less than half the diameter of the effective irradiation area of ​​the first optical element 3. Alternatively, the central part of the effective irradiation area of ​​the first optical element 3 refers to, for example, a range having a diameter from the optical axis of the first optical element 3 that is equal to or less than one-third the diameter of the effective irradiation area of ​​the first optical element 3. Furthermore, the peripheral part of the effective irradiation area of ​​the first optical element 3 refers to a range of the effective irradiation area of ​​the first optical element 3 that does not include the central part.

[0047] First, a case will be described in which the central portion of the effective irradiation area of ​​the first optical element 3 is more likely to fog up than the peripheral portion of the effective irradiation area of ​​the first optical element 3. In such a case, it is preferable that the density of the flow passage through which the first gas 41 flows in the central portion of the rectifying member 107 is higher than the density of the flow passage through which the first gas 41 flows in the peripheral portion of the rectifying member 107 in a plane (XY plane) perpendicular to the optical axis of the projection optical system 2. Here, the flow passage through which the first gas 41 flows in the central portion of the rectifying member 107 refers to the flow passage corresponding to the central portion of the effective irradiation area of ​​the first optical element 3. Furthermore, the flow passage through which the first gas 41 flows in the peripheral portion of the rectifying member 107 refers to the flow passage corresponding to the peripheral portion of the effective irradiation area of ​​the first optical element 3.

[0048] 6 shows an example in which the density of the flow paths through which the first gas 41 flows in the central portion 107A of the rectifying member 107 is higher than the density of the flow paths through which the first gas 41 flows in the peripheral portion 107B. By configuring the rectifying member 107 in this manner, it is possible to intensively remove fogging from the central portion of the effective irradiation area of ​​the first optical element 3. Note that, although an example in which the rectifying member 107 has a structure including a plurality of tubes 107b has been described in FIG. 6, the structure of the rectifying member 107 is not limited to this example.

[0049] Next, a description will be given of a case where the peripheral part of the effective irradiation area of ​​the first optical element 3 is more likely to fog up than the central part of the effective irradiation area of ​​the first optical element 3. In such a case, it is preferable that the density of the flow path through which the first gas 41 flows in the central part of the rectifying member 107 is lower than the density of the flow path through which the first gas 41 flows in the peripheral part of the rectifying member 107 in a plane (XY plane) perpendicular to the optical axis of the projection optical system 2.

[0050] 7 shows an example in which the density of the flow paths through which the first gas 41 flows in the central portion 107A of the rectifying member 107 is lower than the density of the flow paths through which the first gas 41 flows in the peripheral portion 107B. By configuring the rectifying member 107 in this manner, it is possible to intensively remove fogging from the peripheral portion of the effective irradiation area of ​​the first optical element 3. Note that, although an example in which the rectifying member 107 has a structure including a plurality of tubes 107b has been described in FIG. 7, the structure of the rectifying member 107 is not limited to this example.

[0051] As described above, in this embodiment, the rectifying member 107 is used in which the density of the flow passage through which the first gas 41 flows in the central portion of the rectifying member 107 is different from the density of the flow passage through which the first gas 41 flows in the peripheral portion of the rectifying member 107. This makes it possible to intensively clean the portions of the first optical element 3 that are prone to fogging.

[0052] <Third embodiment> The present embodiment differs from the first and second embodiments in the shape of the rectifying member 107. As in the second embodiment, the present embodiment uses a rectifying member 107 that corresponds to the fogging state of the first optical element 3. The second embodiment uses a rectifying member 107 in which the density of the flow path through which the first gas 41 flows in the center of the rectifying member 107 is different from the density of the flow path through which the first gas 41 flows in the peripheral part of the rectifying member 107. The present embodiment uses a rectifying member 107 in which the resistance of the flow path through which the first gas 41 flows in the rectifying member 107 corresponding to the center of the effective irradiation area of ​​the first optical element 3 is different from the resistance of the flow path through which the first gas 41 flows in the rectifying member 107 corresponding to the peripheral part of the effective irradiation area of ​​the first optical element 3.

[0053] It should be noted that the central part of the effective irradiation area of ​​the first optical element 3 in this embodiment refers to, for example, a range having a diameter from the optical axis of the first optical element 3 that is equal to or less than half the diameter of the effective irradiation area of ​​the first optical element 3. Alternatively, the central part of the effective irradiation area of ​​the first optical element 3 refers to, for example, a range having a diameter from the optical axis of the first optical element 3 that is equal to or less than one-third the diameter of the effective irradiation area of ​​the first optical element 3. Furthermore, the peripheral part of the effective irradiation area of ​​the first optical element 3 refers to a range of the effective irradiation area of ​​the first optical element 3 that does not include the central part.

[0054] First, a case will be described in which the central portion of the effective irradiation area of ​​the first optical element 3 is more likely to fog up than the peripheral portion of the effective irradiation area of ​​the first optical element 3. In such a case, it is preferable that the resistance of the flow path through which the first gas 41 flows in the central portion of the rectifying member 107 is smaller than the resistance of the flow path through which the first gas 41 flows in the peripheral portion of the rectifying member 107. Here, the flow path through which the first gas 41 flows in the central portion of the rectifying member 107 refers to the flow path corresponding to the central portion of the effective irradiation area of ​​the first optical element 3. Furthermore, the flow path through which the first gas 41 flows in the peripheral portion of the rectifying member 107 refers to the flow path corresponding to the peripheral portion of the effective irradiation area of ​​the first optical element 3.

[0055] 8 shows an example in which the resistance of the flow path through which the first gas 41 flows in the central portion 107A of the rectifying member 107 is smaller than the resistance of the flow path through which the first gas 41 flows in the peripheral portion 107B of the rectifying member 107. In FIG. 8(a), the thickness (length in the Z-axis direction) of the central portion 107A of the rectifying member 107 is thinner than the thickness of the peripheral portion 107B of the rectifying member 107. This makes it easier for the first gas 41 to flow from the second space 104 to the third space 105 in the central portion 107A of the rectifying member 107 than in the peripheral portion 107B of the rectifying member 107. In other words, the resistance of the flow path through which the first gas 41 flows in the central portion of the rectifying member 107 is smaller than the resistance of the flow path through which the first gas 41 flows in the peripheral portion of the rectifying member 107. By configuring the rectifying member 107 in this manner, it is possible to intensively remove fogging from the center of the effective irradiation area of ​​the first optical element 3.

[0056] 8(b), the diameter of the flow path in central portion 107A of flow rectifying member 107 is larger than the diameter of the flow path in peripheral portion 107B of flow rectifying member 107. This makes it easier for first gas 41 to flow from second space 104 to third space 105 in central portion 107A of flow rectifying member 107 than in peripheral portion 107B of flow rectifying member 107. In other words, the resistance of the flow path through which first gas 41 flows in the central portion of flow rectifying member 107 is smaller than the resistance of the flow path through which first gas 41 flows in the peripheral portion of flow rectifying member 107. By configuring flow rectifying member 107 in this manner, it is possible to intensively remove fogging from the center of the effective irradiation area of ​​first optical element 3.

[0057] Next, a case will be described in which the peripheral part of the effective irradiation area of ​​the first optical element 3 is more likely to fog up than the central part of the effective irradiation area of ​​the first optical element 3. In such a case, it is preferable that the resistance of the flow path through which the first gas 41 flows in the peripheral part of the rectifying member 107 is smaller than the resistance of the flow path through which the first gas 41 flows in the central part of the rectifying member 107.

[0058] 9 shows an example in which the resistance of the flow path through which the first gas 41 flows in the peripheral portion 107B of the rectifying member 107 is smaller than the resistance of the flow path through which the first gas 41 flows in the central portion 107A of the rectifying member 107. In FIG. 9(a), the thickness (length in the Z-axis direction) of the peripheral portion 107B of the rectifying member 107 is thinner than the thickness of the central portion 107A of the rectifying member 107. This makes it easier for the first gas 41 to flow from the second space 104 to the third space 105 in the peripheral portion 107B of the rectifying member 107 than in the central portion 107A of the rectifying member 107. In other words, the resistance of the flow path through which the first gas 41 flows in the peripheral portion of the rectifying member 107 is smaller than the resistance of the flow path through which the first gas 41 flows in the central portion of the rectifying member 107. By configuring the rectifying member 107 in this manner, it is possible to intensively remove fogging from the periphery of the effective irradiation region of the first optical element 3.

[0059] 9(b), the diameter of the flow path in peripheral portion 107B of flow rectifying member 107 is larger than the diameter of the flow path in central portion 107A of flow rectifying member 107. This makes it easier for first gas 41 to flow from second space 104 to third space 105 in peripheral portion 107B of flow rectifying member 107 than in central portion 107A of flow rectifying member 107. In other words, the resistance of the flow path through which first gas 41 flows in the peripheral portion of flow rectifying member 107 is smaller than the resistance of the flow path through which first gas 41 flows in the central portion of flow rectifying member 107. By configuring flow rectifying member 107 in this manner, it is possible to intensively remove fogging from the periphery of the effective irradiation area of ​​first optical element 3.

[0060] The method for making the resistance in the flow path different between the central portion and the peripheral portion of the flow rectifying member 107 is not limited to the example shown in this embodiment. For example, the resistance in the flow path may be made different between the central portion and the peripheral portion by making the materials of the flow rectifying member 107 different between the central portion and the peripheral portion. Alternatively, the resistance in the flow path may be made different between the central portion and the peripheral portion by making the surface roughness of the flow path of the flow rectifying member 107 different between the central portion and the peripheral portion.

[0061] Furthermore, this embodiment may be combined with Embodiment 2. In this embodiment, an example has been shown in which the first gas 41 flows from both the central portion and the peripheral portion of the flow regulating member 107, but if it is known that one of the portions does not fog or is less likely to fog, a structure in which the first gas 41 flows only from the other portion may be used.

[0062] As described above, the rectifying member 107 is used such that the resistance of the flow path of the rectifying member 107 corresponding to the central part of the effective irradiation area of ​​the first optical element 3 is different from the resistance of the flow path of the rectifying member 107 corresponding to the peripheral part of the effective irradiation area of ​​the first optical element 3. This makes it possible to intensively clean the parts of the first optical element 3 that are prone to fogging.

[0063] <Fourth embodiment> This embodiment relates to a method for manufacturing an article, characterized in that the article is manufactured using the cleaning method described above.

[0064] 10 is a flowchart showing a method for manufacturing an article according to this embodiment. First, a first space 103 is formed in the image-side region of a first optical element 3, which is arranged closest to the image side among the multiple optical elements included in the optical system, and a first member 100 is arranged to separate the first space 103 from a space further to the image side than the first space 103 (arrangement step, S210). Next, a first gas 41 is supplied while light passing through the optical system is irradiated into the first space 103 (supply step, S220). Next, the first member 100 is retracted (retraction step, S230).

[0065] Next, a pattern is formed on the substrate using an optical system (forming step, S240), and the substrate on which the pattern has been formed in the forming step is processed (processing step, S250).

[0066] Products manufactured by this manufacturing method include, for example, semiconductor IC elements, liquid crystal display elements, color filters, MEMS, and the like.

[0067] In the forming step, for example, a substrate (silicon wafer, glass plate, etc.) coated with a photosensitive material is exposed by an exposure apparatus (lithography apparatus) to form a pattern on the substrate.

[0068] The processing steps include, for example, developing the substrate (photosensitive material) on which the pattern is formed, etching the developed substrate, removing the resist, dicing, bonding, and packaging. This manufacturing method makes it possible to manufacture products of higher quality than conventional methods.

[0069] The disclosure of the present specification includes the following cleaning apparatus, exposure apparatus, cleaning method, and method for manufacturing an article.

[0070] [Item 1] A cleaning device that cleans an image-side surface of a first optical element that is disposed closest to an image side among a plurality of optical elements included in an optical system, a first member that forms a first space in an area on the image side of the first optical element and separates the first space from a space located further to the image side than the first space; a gas supply unit that supplies a gas to the first space, The cleaning device is characterized in that the gas supply unit supplies the gas when the first space is irradiated with light that has passed through the optical system.

[0071] [Item 2] Item 1. The cleaning device according to item 1, wherein the area of ​​the surface of the first member facing the first optical element is larger than the area of ​​an effective irradiation region on the image-side surface of the first optical element.

[0072] [Item 3] a second member that divides the first space into a second space and a third space in a direction perpendicular to the optical axis of the optical system; the second member includes a structure that allows the gas to flow from the second space to the third space through the second member, 3. The cleaning device according to item 1 or 2, wherein the gas supply unit supplies the gas to the second space and causes the gas to flow into the third space via the second member.

[0073] [Item 4] 4. The cleaning device according to item 3, wherein the second member includes at least one of a porous structure, a structure including a plurality of tubes, a lattice-like structure, and a structure having a plurality of holes.

[0074] [Item 5] Item 4. The cleaning device according to item 3, characterized in that, in a plane perpendicular to the optical axis of the optical system, the density of the flow paths through which the gas flows in the second member corresponding to the central part of the effective irradiation area of ​​the first optical element is the same as the density of the flow paths through which the gas flows in the second member corresponding to the peripheral part of the effective irradiation area of ​​the first optical element.

[0075] [Item 6] Item 4. The cleaning device according to item 3, characterized in that, in a plane perpendicular to the optical axis of the optical system, the density of the flow paths through which the gas flows in the second member corresponding to the central part of the effective irradiation area of ​​the first optical element is lower than the density of the flow paths through which the gas flows in the second member corresponding to the peripheral part of the effective irradiation area of ​​the first optical element.

[0076] [Item 7] Item 4. The cleaning device according to item 3, characterized in that, in a plane perpendicular to the optical axis of the optical system, the density of the flow paths through which the gas flows in the second member corresponding to the central part of the effective irradiation area of ​​the first optical element is higher than the density of the flow paths through which the gas flows in the second member corresponding to the peripheral part of the effective irradiation area of ​​the first optical element.

[0077] [Item 8] 4. The cleaning device according to item 3, characterized in that the resistance of the flow path through which the gas flows in the second member corresponding to the central part of the effective irradiation area of ​​the first optical element is different from the resistance of the flow path through which the gas flows in the second member corresponding to the peripheral part of the effective irradiation area of ​​the first optical element.

[0078] [Item 9] The cleaning device according to any one of items 1 to 8, wherein the optical system is one of an illumination optical system that illuminates an original on which a pattern is formed with light from a light source, a projection optical system that projects light that has passed through the original onto a substrate, and a measurement optical system that measures an alignment mark formed on the substrate or a stage that holds the substrate.

[0079] [Item 10] the gas is an oxygen-containing gas, 10. The cleaning device according to any one of items 1 to 9, wherein ozone is generated by irradiating the gas with the light.

[0080] [Item 11] 11. The cleaning device according to any one of items 1 to 10, wherein a surface of the first member facing the first optical element includes a reflecting member.

[0081] [Item 12] 4. The cleaning device according to claim 3, wherein the second member is transparent.

[0082] [Item 13] The cleaning device described in any one of items 1 to 12, characterized in that the first member is placed in an area on the image side of the first optical element before a cleaning operation on the first optical element, and is retracted from the area on the image side of the first optical element after the cleaning operation.

[0083] [Item 14] Item 14. The cleaning device according to item 13, further comprising a drive unit that moves the first member in or out of position.

[0084] [Item 15] a drive unit that drives a first member to form a first space in an image-side region of a first optical element that is arranged closest to the image side among a plurality of optical elements included in the optical system, and to place a first member that separates the first space from a space that is further to the image side than the first space; a gas supply unit that supplies a gas to the first space, an exposure apparatus, wherein the gas supply unit supplies the gas when the first space is irradiated with light that has passed through the optical system;

[0085] [Item 16] Item 16. The exposure apparatus according to item 15, wherein the light is exposure light used in an exposure process.

[0086] [Item 17] A cleaning method for cleaning an image-side surface of a first optical element that is disposed closest to an image side among a plurality of optical elements included in an optical system, comprising: a disposing step of forming a first space in an image side region of the first optical element and disposing a first member that separates the first space from a space located further to the image side than the first space; a supplying step of supplying a gas while the first space is irradiated with light via the optical system; A cleaning method comprising:

[0087] [Item 18] an arrangement step of forming a first space in an image-side region of a first optical element that is arranged closest to the image side among a plurality of optical elements included in the optical system, and arranging a first member that separates the first space from a space that is further to the image side than the first space; a supplying step of supplying a gas while the first space is irradiated with light via the optical system; a retracting step of retracting the first member; a forming step of forming a pattern on a substrate using the optical system after the retracting step; a processing step of processing the substrate on which the pattern has been formed in the forming step; A method for manufacturing an article, comprising:

[0088] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention.

Claims

1. A cleaning device that cleans an image-side surface of a first optical element that is disposed closest to an image side among a plurality of optical elements included in an optical system, a first member that forms a first space in an area on the image side of the first optical element and separates the first space from a space located further to the image side than the first space; a gas supply unit that supplies a gas to the first space, The cleaning device, wherein the gas supply unit supplies the gas when the first space is irradiated with light that has passed through the optical system.

2. 2. The cleaning device according to claim 1, wherein an area of ​​a surface of the first member facing the first optical element is larger than an area of ​​an effective irradiation region on an image-side surface of the first optical element.

3. a second member that divides the first space into a second space and a third space in a direction perpendicular to the optical axis of the optical system; the second member includes a structure that allows the gas to flow from the second space to the third space through the second member, The cleaning device according to claim 1 , wherein the gas supply unit supplies the gas to the second space and causes the gas to flow into the third space via the second member.

4. 4. The cleaning device according to claim 3, wherein the second member includes at least one of a porous structure, a structure including a plurality of tubes, a lattice-like structure, and a structure provided with a plurality of holes.

5. 4. The cleaning device according to claim 3, wherein, in a plane perpendicular to the optical axis of the optical system, the density of the flow paths through which the gas flows in the second member corresponding to the central part of the effective irradiation area of ​​the first optical element is the same as the density of the flow paths through which the gas flows in the second member corresponding to the peripheral part of the effective irradiation area of ​​the first optical element.

6. 4. The cleaning device according to claim 3, wherein, in a plane perpendicular to the optical axis of the optical system, the density of the flow paths through which the gas flows in the second member corresponding to the central part of the effective irradiation area of ​​the first optical element is lower than the density of the flow paths through which the gas flows in the second member corresponding to the peripheral part of the effective irradiation area of ​​the first optical element.

7. 4. The cleaning device according to claim 3, wherein, in a plane perpendicular to the optical axis of the optical system, the density of the flow paths through which the gas flows in the second member corresponding to the central part of the effective irradiation area of ​​the first optical element is higher than the density of the flow paths through which the gas flows in the second member corresponding to the peripheral part of the effective irradiation area of ​​the first optical element.

8. 4. The cleaning device according to claim 3, wherein the resistance of the flow path through which the gas flows in the second member corresponding to the central part of the effective irradiation area of ​​the first optical element is different from the resistance of the flow path through which the gas flows in the second member corresponding to the peripheral part of the effective irradiation area of ​​the first optical element.

9. 2. The cleaning device according to claim 1, wherein the optical system is one of an illumination optical system that illuminates an original on which a pattern is formed with light from a light source, a projection optical system that projects light that passes through the original onto a substrate, and a measurement optical system that measures an alignment mark formed on the substrate or a stage that holds the substrate.

10. the gas is an oxygen-containing gas, 2. The cleaning device according to claim 1, wherein ozone is generated by irradiating the gas with the light.

11. 2. The cleaning device according to claim 1, wherein a surface of the first member facing the first optical element includes a reflecting member.

12. 4. The cleaning device according to claim 3, wherein the second member is transparent.

13. 2. The cleaning device according to claim 1, wherein the first member is disposed in an area on the image side of the first optical element before a cleaning operation on the first optical element, and is retracted from the area on the image side of the first optical element after the cleaning operation.

14. 14. The cleaning device according to claim 13, further comprising a drive unit that moves the first member in the direction of or out of the direction of movement of the first member.

15. a drive unit that drives a first member to form a first space in an image-side region of a first optical element that is arranged closest to the image side among a plurality of optical elements included in the optical system, and to place a first member that separates the first space from a space that is further to the image side than the first space; a gas supply unit that supplies a gas to the first space, an exposure apparatus, wherein the gas supply unit supplies the gas when the first space is irradiated with light that has passed through the optical system;

16. 16. An exposure apparatus according to claim 15, wherein the light is exposure light used in an exposure process.

17. 1. A cleaning method for cleaning an image-side surface of a first optical element that is disposed closest to an image side among a plurality of optical elements included in an optical system, comprising: a disposing step of forming a first space in an area on the image side of the first optical element and disposing a first member that separates the first space from a space located further to the image side than the first space; a supplying step of supplying a gas while the first space is irradiated with light via the optical system; A cleaning method comprising:

18. an arrangement step of forming a first space in an image-side region of a first optical element that is arranged closest to the image side among a plurality of optical elements included in the optical system, and arranging a first member that separates the first space from a space that is further to the image side than the first space; a supplying step of supplying a gas while the first space is irradiated with light via the optical system; a retracting step of retracting the first member; a forming step of forming a pattern on a substrate using the optical system after the retracting step; a processing step of processing the substrate on which the pattern has been formed in the forming step; A method for manufacturing an article, comprising:

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