Light source device, lighting method, and manufacturing method of light source device

Abstract

To provide a light source device, an illumination method, and a method for manufacturing a light source device in which a reduction in light quantity of EUV light can be suppressed.SOLUTION: A light source device (1) comprises: a target material (11) which generates EUV light (15) by irradiation of a laser beam (13); a collector mirror (30) which reflects the EUV light; an exhaust case (40) having an outer cover (41) arranged between the target material and the collector mirror, and an exhaust port (42) which leads to an exhaust space (43) formed closer to the target material than the outer cover; a cylindrical optical path cover (50) in which an opening diameter of another end (52) is larger than an opening diameter of one end (51); and a filter (60) which is arranged at the other end or inside of the optical path cover, and transmits EUV light. Purge gas (44) introduced from an introduction port (53) formed in the optical path cover is ejected from the one end (51) of the optical path cover toward the target material, passes through the exhaust space, and is exhausted from the exhaust port (42).SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a light source device, an illumination method, and a method for manufacturing a light source device. [Background technology]

[0002] Non-Patent Documents 1 to 3 disclose a light source that irradiates a target material containing xenon formed on the surface of a rotating drum with laser light, and generates EUV light from the generated plasma. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] "Progress towards Actinic Patterned Mask Inspection," Oleg Khodykin, Workshop Proceedings, 2015 International Workshop on EUV Lithography, June 15, 2015, [Retrieved March 6, 2023], Internet<https: / / www.euvlitho.com / 2015 / P51.pdf> [Non-patent document 2] "Bright and reliable Xe-based EUV source for metrology and inspection applications," Oleg Khodykin, Workshop Proceedings, 2015 International Workshop on EUV and Soft X-Ray Sources, November 9, 2015, [Retrieved March 6, 2023], Internet<https: / / www.euvlitho.com / 2015 / S31.pdf> [Non-patent document 3] "Status of Actinic Patterned Mask Inspection at KLA-Tencor," Oleg Khodykin, Workshop Proceedings, 2016 International Workshop on EUV and Soft X-Ray Sources, November 7, 2016, [Retrieved March 6, 2023], Internet<https: / / www.euvlitho.com / 2016 / S19.pdf> Summary of the Invention

[0004] In addition to the methods described in Non-Patent Documents 1 to 3, there is also a method of generating EUV light by rotating a liquid molten metal containing tin placed in a container such as a crucible and irradiating the molten metal with laser light to generate plasma, from which EUV light is generated. In all of these methods, optical elements such as mirrors are deteriorated by debris formed from target materials such as xenon, tin, and lithium during plasma generation. This is a serious problem for EUV light sources.

[0005] Previously, methods have been proposed to suppress debris by flowing inert gas into the laser beam path or near the mirror, but these methods pose problems such as the absorption of EUV light by the diffused inert gas and gasified target material, and the inability to sufficiently suppress debris formation, which still leads to contamination of optical elements, resulting in a reduction in the amount of EUV light.

[0006] The present disclosure has been made to solve such problems, and provides a light source device, an illumination method, and a method for manufacturing a light source device that can suppress a decrease in the amount of EUV light.

[0007] a collector mirror that reflects the generated EUV light; an outer cover disposed between the target material and the collector mirror; and an exhaust case having an exhaust port that leads to an exhaust space formed on the target material side of the outer cover; a cylindrical optical path cover having one open end and the other open end, the opening diameter of which is larger than the opening diameter of the one end, the optical path cover having one end facing the target material and the other end disposed on the collector mirror side of the outer cover; and a filter that is disposed at the other end of the optical path cover or within the optical path cover and that transmits the EUV light. Purge gas introduced from an inlet formed in the optical path cover is ejected from the one end of the optical path cover toward the target material, passes through the exhaust space, and is exhausted from the exhaust port.

[0008] a collector mirror that reflects the generated EUV light; an outer cover arranged between the target material and the collector mirror; and an exhaust case having an exhaust port that leads to an exhaust space formed on the target material side of the outer cover; a transparent member that transmits the laser light; and a cylindrical laser path cover that has one open end and another open end, the opening diameter of which is larger than the opening diameter of the one end, wherein the one end of the laser path cover faces the target material, and the transparent member is arranged at the other end of the laser path cover or within the laser path cover, and purge gas introduced from an inlet formed in the laser path cover is sprayed from the one end of the laser path cover toward the target material, passes through the exhaust space, and is exhausted from the exhaust port.

[0009] In the light source device described above, the outer cover may separate the exhaust space in which the target material is disposed from an optical path space in which the collector mirror is disposed.

[0010] The light source device described above may further include a cylindrical drum that rotates around its central axis as a rotation axis and is cooled so that the target material is solidified on its surface, a housing having an opening facing the irradiation position of the laser light, and a supply case having a supply port that leads to a supply space formed on the target material side of the housing, and the target material gas supplied from the supply port may be solidified on the surface of the drum to form the target material.

[0011] The light source device may further include a cylindrical crucible that rotates about a central axis and has one open end and the other closed end, the crucible being heated so that the target material melts on its inner surface, and a debris shield having an opening in a portion facing the irradiation position of the laser light, and the target material is formed by spreading the liquid target material over the inner surface of the crucible.

[0012] an exhaust case having an exhaust port leading to an exhaust space formed on the target material side of the outer cover; a cylindrical optical path cover having one open end and the other open end, the one end facing the target material and the other end being located on the collector mirror side of the outer cover; and a filter disposed at the other end of the optical path cover or within the optical path cover, the filter transmitting the EUV light; introducing a purge gas from an inlet formed in the optical path cover, and ejecting the introduced purge gas from the one end of the optical path cover toward the target material, and exhausting the purge gas from the exhaust port through the exhaust space; and generating the EUV light by irradiating the target material with the laser light.

[0013] an exhaust case having an exhaust port that leads to an exhaust space formed on the target material side of the outer cover; a transparent member that transmits the laser light; and a cylindrical laser path cover having one open end and another open end, the opening diameter of which is larger than the opening diameter of the one end, wherein the one end of the laser path cover faces the target material, and the transparent member is disposed at the other end of the laser path cover or within the laser path cover;

[0014] In the above illumination method, the outer cover may separate the exhaust space in which the target material is disposed from an optical path space in which the collector mirror is disposed.

[0015] In the above-described illumination method, the light source device may further include a cylindrical drum that rotates around its central axis as a rotation axis, the drum being cooled so that the target material is solidified on its surface, a housing having an opening in a portion facing the irradiation position of the laser light, and a supply case having a supply port that leads to a supply space formed on the target material side of the housing, and in the step of preparing the light source device, the target material may be formed by supplying a gas of the target material from the supply port to the supply space and solidifying the supplied gas of the target material on the surface of the drum.

[0016] In the above-described illumination method, the light source device may further include a cylindrical crucible that rotates about a central axis and has one open end and the other closed end, the crucible being heated so that the target material melts on its inner surface, and a debris shield having an opening in a portion facing the irradiation position of the laser light, and in the step of preparing the light source device, the target material may be formed by spreading the liquid target material on the inner surface of the crucible.

[0017] A method for manufacturing a light source device according to one aspect of the present embodiment includes the steps of: preparing a light source including a target material that generates EUV light together with plasma by irradiating it with laser light; and a collector mirror that reflects the generated EUV light; arranging an exhaust case by disposing an outer cover between the target material and the collector mirror and forming an exhaust port so as to communicate with an exhaust space formed on the target material side of the outer cover; disposing a cylindrical optical path cover that has one open end and the other open end, the opening diameter of which is larger than the opening diameter of the one end, so that the one end faces the target material and the other end is on the collector mirror side of the outer cover; disposing a filter that transmits the EUV light at the other end of the optical path cover or within the optical path cover; and forming an inlet in the optical path cover through which a purge gas is introduced.

[0018] A method for manufacturing a light source device according to one aspect of the present embodiment includes the steps of: preparing a light source including a target material that generates EUV light together with plasma by irradiating it with laser light; and a collector mirror that reflects the generated EUV light; arranging an outer cover between the target material and the collector mirror, and arranging an exhaust case by forming an exhaust port so as to communicate with an exhaust space formed on the target material side of the outer cover; arranging a cylindrical laser path cover that has one open end and the other open end, the opening diameter of which is larger than the opening diameter of the one end, such that the one end of the laser path cover faces the target material and the other end of the laser path cover passes through; arranging a transparent member that transmits the laser light at the other end of the laser path cover or within the laser path cover; and forming an inlet in the laser path cover through which a purge gas is introduced.

[0019] In the above-described method for manufacturing a light source device, the outer cover may be arranged to separate the exhaust space in which the target material is arranged from an optical path space in which the collector mirror is arranged.

[0020] In the above-mentioned method for manufacturing a light source device, the light source may further include a cylindrical drum that rotates around its central axis as a rotation axis, the drum being cooled so that the target material is solidified on its surface, a housing having an opening in a portion facing the irradiation position of the laser light, and a supply case having a supply port that leads to a supply space formed on the target material side of the housing, and the method may further include a step of forming the target material by supplying a gas of the target material from the supply port to the supply space and solidifying the supplied gas of the target material on the surface of the drum.

[0021] In the above-mentioned method for manufacturing a light source device, the light source may further include a cylindrical crucible that rotates about a central axis and has one open end and the other closed end, the crucible being heated so that the target material melts on its inner surface, and a debris shield having an opening in a portion facing the irradiation position of the laser light, and the method may further include a step of forming the target material by spreading the liquid target material on the inner surface of the crucible.

[0022] According to the present disclosure, it is possible to provide a light source device, an illumination method, and a method for manufacturing a light source device that can suppress a decrease in the amount of EUV light. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 10 is a perspective view illustrating a light source according to a comparative example. [Figure 2] 2 is a cross-sectional view illustrating a light source according to a comparative example, which is a schematic cross-section taken along line II-II in FIG. 1. FIG. [Figure 3] 3 is a cross-sectional view illustrating a light source according to a comparative example, which is a schematic cross-section taken along line III-III in FIG. 1. FIG. [Figure 4] FIG. 10 is a cross-sectional view illustrating a light source according to a comparative example. [Figure 5] 1 is a cross-sectional view illustrating a light source device according to a first embodiment. [Figure 6] 4 is a flowchart illustrating an illumination method using the light source device according to the first embodiment. FIG. [Figure 7] 4 is a flowchart illustrating a method for manufacturing the light source device according to the first embodiment. [Figure 8] FIG. 10 is a diagram illustrating the flow of purge gas in a light source according to a comparative example. [Figure 9] FIG. 10 is a diagram illustrating the flow of purge gas in a light source according to a comparative example. [Figure 10] FIG. 10 is a diagram illustrating the flow of purge gas in a light source according to a comparative example. [Figure 11] FIG. 10 is a diagram illustrating the flow of purge gas in a light source according to a comparative example. [Figure 12] FIG. 10 is a cross-sectional view illustrating a light source device according to a second embodiment. [Figure 13] FIG. 10 is a cross-sectional view illustrating a light source device according to a third embodiment. [Figure 14] FIG. 10 is a cross-sectional view illustrating a light source device according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The following description shows preferred embodiments of the present disclosure, and the scope of the present disclosure is not limited to the following embodiments. In the following description, components with the same reference numerals indicate substantially similar content.

[0025] Before describing the light source device of the embodiment, a light source of the comparative example will be described in <Comparative Example>. Then, a problem that the inventor found with the light source of the comparative example will be described in <Problems Found by the Inventor>. Then, in <Embodiment 1> and <Embodiment 2>, the light source device, lighting method, and manufacturing method of the light source device of the present embodiment will be described.

[0026] <Comparative Example> Fig. 1 is a perspective view illustrating a light source 101 according to a comparative example. Fig. 2 is a cross-sectional view illustrating the light source 101 according to the comparative example, which is a schematic cross-section taken along line II-II in Fig. 1. Fig. 3 is a cross-sectional view illustrating the light source 101 according to the comparative example, which is a schematic cross-section taken along line III-III in Fig. 1. Note that some symbols and some hatching have been omitted to avoid cluttering the drawings.

[0027] 1 to 3, a light source 101 of the comparative example includes a drum 10, a target material 11, and a supply case 20. The supply case 20 has a housing 21 and a supply port 22. The supply case 20 may further include a wiper 25, a vacuum seal 26, an injection port 27, and a window 28.

[0028] The drum 10 is cylindrical and has a central axis C. The drum 10 rotates around the central axis C as its rotation axis. The drum 10 may also move in the direction of the central axis C.

[0029] Here, for ease of explanation of the light source 101, an XYZ Cartesian coordinate system is introduced. The direction in which the central axis C of the drum 10 extends is defined as the Z-axis direction. A plane perpendicular to the central axis C of the drum 10 is defined as the XY plane. For example, the +Z-axis direction is defined as the up direction, and the -Z-axis direction is defined as the down direction. Note that up and down are used for ease of explanation of the light source 101, and do not indicate the directions in which the actual light source 101 is disposed.

[0030] The drum 10 contains, for example, copper as a material. A coolant 12 such as liquid nitrogen is supplied to the inside of the drum 10. Thus, the drum 10 is cooled so that the target material 11 is solidified on the surface. Note that the material of the drum 10 is not limited to copper and may contain other materials as long as the surface temperature of the drum 10 can be kept below the solidification point of the target material 11.

[0031] When irradiated with laser light 13, target material 11 generates plasma 14 and EUV light 15. Target material 11 is formed on the surface of drum 10. Target material 11 contains, for example, xenon (Xe). Note that target material 11 is not limited to xenon, and may contain tin (Sn), lithium (Li), or the like, as long as it generates plasma 14 and EUV light 15 when irradiated with laser light 13.

[0032] The supply case 20 has a housing 21 and a supply port 22. The housing 21 covers the drum 10. The housing 21 is, for example, cylindrical and hollow inside. The drum 10 is disposed inside the housing 21. The drum 10 rotates inside the housing 21. The housing 21 has an opening facing the irradiation position 17 of the laser beam 13. Therefore, the housing 21 may cover the target material 11 other than the irradiation position 17 of the laser beam 13. The housing 21 forms a space closer to the target material 11 than the housing 21. The space formed closer to the target material 11 than the housing 21 is called a supply space 23.

[0033] The supply port 22 communicates with the supply space 23. The supply port 22 is also connected to a supply unit 24 for a gas 16 of the target material 11. The supply unit 24 supplies the gas 16 of the target material 11 to the supply space 23 via the supply port 22. The gas 16 of the target material 11 supplied from the supply port 22 is solidified on the surface of the drum 10, thereby forming the target material 11.

[0034] The laser beam 13 irradiates the target material 11 solidified on the surface of the drum 10. This generates plasma 14 from the target material 11. Therefore, EUV light 15 can be generated from the generated plasma 14. The drum 10 moves in the direction of the central axis C while rotating around the central axis C. Therefore, the irradiation position 17 of the laser beam 13 is always on the target material 11 that has not been irradiated with the laser beam 13.

[0035] The laser beam 13 may be irradiated onto the target material 11 through a transparent member 70 such as a condenser lens and a window 28. A wiper 25 may form the target material 11 solidified on the surface of the drum 10. A vacuum seal 26 seals the inside of the light source 101. An inlet 27 leads to the inside of the drum 10. Liquid nitrogen is injected into the inside of the drum 10 through the inlet 27.

[0036] <Problems discovered by the inventors> 4 is a cross-sectional view illustrating a light source 101 according to a comparative example. As shown in FIG. 4, in the light source 101 of the comparative example, EUV light 15 generated by irradiating with laser light 13 is reflected by a collector mirror 30 and extracted to the outside of the light source 101. When the EUV light 15 is generated, debris 18 may be generated from the target material 11 along with the generation of plasma 14. The generated debris 18 adheres to optical elements such as the collector mirror 30, reducing the amount of reflected and transmitted EUV light 15 from the optical elements.

[0037] Therefore, in order to suppress adhesion of debris 18 to the optical elements, a purge gas 44 containing an inert gas or the like may be flowed in the optical path of the laser beam 13 and near the optical elements to suppress adhesion of debris 18. The purge gas 44 may contain, for example, at least one of argon (Ar), helium (He), nitrogen (N), and hydrogen (H), or may contain other gases. However, there is a problem in that the EUV light 15 is absorbed by the diffused purge gas 44 and the gas 16 of the gasified target material 11, reducing the amount of EUV light 15. Furthermore, there is a problem in that the generated debris 18 is not sufficiently suppressed, resulting in deterioration of the optical elements and a reduction in the amount of EUV light 15.

[0038] <Embodiment 1> Next, a light source device according to embodiment 1 will be described. The light source device according to this embodiment limits the diffusion range of the purge gas 44 and the gas 16 of the target material 11, thereby maintaining the optical path of the EUV light 15 at a high vacuum, suppressing absorption of the EUV light 15 by the purge gas 44, etc., and improving the effect of removing debris 18.

[0039] Fig. 5 is a cross-sectional view illustrating a light source device 1 according to embodiment 1. As shown in Fig. 5, the light source device 1 of this embodiment includes a drum 10, a target material 11, a supply case 20, a collector mirror 30, an exhaust case 40, a light path cover 50, a filter 60, a transparent member 70, and a light path cover 80. The configurations of the drum 10, the target material 11, and the supply case 20 in the light source device 1 are similar to those in the light source 101 of the comparative example.

[0040] The collector mirror 30 reflects the EUV light 15 generated by irradiating the target material 11 with the laser light 13. The collector mirror 30 reflects the EUV light 15, for example, to an illumination optical system of an inspection device. This allows the inspection device to use the EUV light 15 as inspection light. Note that the collector mirror 30 may reflect the EUV light 15 not only to an inspection device but also to other optical devices such as an exposure device.

[0041] The exhaust case 40 has an outer cover 41 and an exhaust port 42. The outer cover 41 is disposed between the target material 11 and the collector mirror 30. Specifically, the outer cover 41 includes a portion disposed between the target material 11 and the collector mirror 30. The outer cover 41 may cover the supply case 20. In this embodiment, the outer cover 41 is cylindrical and hollow inside. The supply case 20 is disposed inside the outer cover 41. The outer cover 41 forms a space closer to the target material 11 than the outer cover 41. The space formed closer to the target material 11 than the outer cover 41 is called an exhaust space 43.

[0042] The exhaust port 42 communicates with the exhaust space 43. The exhaust port 42 may also be connected to an exhaust pump, which allows the exhaust space 43 to be evacuated via the exhaust port 42.

[0043] The light path cover 50 is disposed between the target material 11 and the collector mirror 30. The light path cover 50 has a cone shape or a hollow truncated cone shape. Specifically, the light path cover 50 is cylindrical with an open one end 51 and an open other end 52, but the opening diameter of the other end 52 is larger than the opening diameter of the one end 51, and the diameter increases from the opening of the one end 51 toward the opening of the other end 52. The one end 51 of the light path cover 50 faces the target material 11 on the target material 11 side relative to the outer cover 41. The other end 52 of the light path cover 50 is disposed so as to face the collector mirror 30 on the collector mirror 30 side relative to the outer cover 41.

[0044] The optical path cover 50 is disposed so as to penetrate the outer cover 41. That is, one end 51 of the optical path cover 50 protrudes further into the exhaust space 43 on the target material 11 side than the outer cover 41. The other end 52 of the optical path cover 50 protrudes further into the space on the collector mirror 30 side than the outer cover 41. The space on the collector mirror 30 side than the outer cover 41 is called an optical path space 46. The exhaust space 43 in which the target material 11 is disposed and the optical path space 46 in which the collector mirror 30 is disposed are connected by the optical path cover 50. The outer cover 41 separates the exhaust space 43 in which the target material 11 is disposed from the optical path space 46 in which the collector mirror 30 is disposed. It is desirable that the optical path space 46 be maintained in a high vacuum state by an exhaust pump such as a vacuum pump.

[0045] The filter 60 is arranged to close the other end 52 of the light path cover 50. The filter 60 transmits the EUV light 15. An inlet 53 for introducing the purge gas 44 is formed in the light path cover 50. For example, the inlet 53 is formed on the light path cover 50 closer to the collector mirror 30 than the outer cover 41. The purge gas 44 introduced from the inlet 53 is ejected from one end 51 of the light path cover 50 toward the target material 11, passes through the exhaust space 43, and is exhausted from the exhaust port 42.

[0046] The transparent member 70 transmits the laser beam 13. The transparent member 70 may be, for example, a condenser lens 70b that condenses the laser beam 13, or a glass plate 70a. Note that the transparent member 70 is not limited to the condenser lens 70b and the glass plate 70a, and may be another optical member as long as it can transmit the laser beam 13.

[0047] The light path cover 80 is disposed between the target material 11 and the transparent member 70. The light path cover 80 is also referred to as a laser light path member. The light path cover 80 has a cone shape or a hollow truncated cone shape. Specifically, the light path cover 80 is cylindrical with an open one end 81 and an open other end 82, but the opening diameter of the other end 82 is larger than the opening diameter of the one end 81, and the diameter increases from the opening of the one end 81 toward the opening of the other end 82. One end 81 of the light path cover 80 faces the target material 11, and the other end 82 is disposed to face the transparent member 70.

[0048] The light path cover 80 may be disposed so as to penetrate the outer cover 41. That is, one end 81 of the light path cover 80 protrudes further into the exhaust space 43 on the target material 11 side than the outer cover 41. The other end 82 of the light path cover 80 protrudes further into the space on the transparent member 70 side than the outer cover 41. The space on the transparent member 70 side than the outer cover 41 may be connected to the light path space 46. The exhaust space 43 in which the target material 11 is disposed and the space in which the transparent member 70 is disposed are connected by the light path cover 80. The outer cover 41 separates the exhaust space 43 in which the target material 11 is disposed from the light path space 46 in which the transparent member 70 is disposed.

[0049] The transparent member 70 is disposed so as to close the other end 82 of the optical path cover 80. An inlet 83 for introducing the purge gas 44 is formed in the optical path cover 80. For example, the inlet 83 is formed on the optical path cover 80 closer to the transparent member 70 than the outer cover 41. The purge gas 44 introduced from the inlet 83 is ejected from one end 81 of the optical path cover 80 toward the target material 11, passes through the exhaust space 43, and is exhausted from the exhaust port 42.

[0050] As described above, in the light source device 1 of this embodiment, the target material 11 is surrounded by the exhaust case 40, and the optical path space 46 in which the EUV light 15 and the laser light 13 are disposed is separated from the exhaust space 43 in which the target material 11 is disposed. The other end 52 of the optical path cover 50 is sealed with a filter 60, and the other end 82 of the optical path cover 80 is sealed with a transparent member 70. This configuration forms a flow of purge gas 44, such as an inert gas (Ar, He, N2, and H2), from one end 81 of the optical path cover 80, which is the entrance port for the laser light 13, and one end 51 of the optical path cover 50, which is the exit port for the EUV light 15, toward the exhaust port 42. This limits the range in which the gas pressure of the purge gas 44, etc., is high, thereby improving the effectiveness of removing debris 18.

[0051] Furthermore, by making the optical path cover 50 and the optical path cover 80 cone-shaped so that the diameter narrows toward the one end 51 and the one end 81, respectively, the gas pressure and gas flow rate at the one end 51 and the one end 81 can be efficiently increased, and the debris 18 removal effect can be improved.

[0052] Next, an illumination method using the light source device 1 will be described as an operation of this embodiment. Fig. 6 is a flow chart illustrating an illumination method using the light source device 1 according to embodiment 1. As shown in Fig. 6, the illumination method includes a step (S11) of preparing the light source device 1, a step (S12) of ejecting a purge gas 44, and a step (S13) of generating EUV light 15.

[0053] First, as shown in step S11, the light source device 1 is prepared. The light source device 1 includes a target material 11, a collector mirror 30, an exhaust case 40, an optical path cover 50, and a filter 60. The light source device 1 may further include a drum 10, a supply case 20, a transparent member 70, and an optical path cover 80.

[0054] In step S11, the gas 16 of the target material 11 may be supplied from the supply port 22 to the supply space 23, and the supplied gas 16 of the target material 11 may be solidified on the surface of the drum 10, thereby forming the target material 11.

[0055] Next, as shown in step S12, the purge gas 44 is ejected. Specifically, the purge gas 44 is introduced from the inlet 53 formed in the optical path cover 50, and the introduced purge gas 44 is ejected from one end 51 of the optical path cover 50 toward the target material 11. Then, the purge gas 44 is exhausted from the exhaust outlet 42 through the exhaust space 43.

[0056] In step S12, purge gas 44 may be introduced from an inlet 83 formed in the optical path cover 80, and the introduced purge gas 44 may be ejected from one end 81 of the optical path cover 80 toward the target material 11. Then, the purge gas 44 may be exhausted from an exhaust port 42 through an exhaust space 43.

[0057] Next, as shown in step S13, EUV light 15 is generated. Specifically, the EUV light 15 is generated by irradiating the target material 11 with laser light 13. By generating illumination light containing EUV light 15 in this manner, illumination light in an inspection device or the like can be formed.

[0058] Next, a method for manufacturing the light source device 1 of this embodiment will be described. In the method for manufacturing the light source device 1 of this embodiment, for example, the light source device 1 is manufactured from a light source 101 of a comparative example. FIG. 7 is a flowchart illustrating a method for manufacturing the light source device 1 according to the first embodiment. As shown in FIG. 7, the method for manufacturing the light source device 1 includes a step (S21) of preparing the light source 101, a step (S22) of arranging the exhaust case 40, a step (S23) of arranging the light path cover 50, a step (S24) of arranging the filter 60, and a step (S25) of forming the inlet 53 for the purge gas 44. Note that the order of steps S22 to S25 is not limited to this order, and the light source device 1 may be manufactured in another order, or any of the steps may be performed in parallel.

[0059] As shown in step S21, the light source 101 is prepared. The light source 101 includes a target material 11 and a collector mirror 30. The light source 101 may further include a drum 10 and a supply case 20.

[0060] Next, as shown in step S22, the exhaust case 40 is arranged. Specifically, the outer cover 41 is arranged between the target material 11 and the collector mirror 30. An exhaust port 42 is then formed so as to communicate with an exhaust space 43 formed on the target material 11 side of the outer cover 41. The outer cover 41 may be arranged so as to surround the target material 11. The exhaust case 40 is arranged in this manner. The outer cover 41 is preferably arranged so as to separate the exhaust space 43 in which the target material 11 is arranged from the optical path space 46 in which the collector mirror 30 is arranged. This makes it possible to prevent the amount of EUV light 15 from being reduced by the purge gas 44 and the gas 16 of the target material 11.

[0061] Next, as shown in step S23, the light path cover 50 is placed. Specifically, the light path cover 50 is placed so that one end 51 faces the target material 11 on the target material 11 side of the outer cover 41, and the other end 52 faces the collector mirror 30 on the collector mirror 30 side of the outer cover 41.

[0062] Next, as shown in step S24, the filter 60 is disposed. Specifically, the filter 60, which transmits the EUV light 15, is disposed so as to close the other end 52 of the light path cover 50.

[0063] Next, as shown in step S25, an inlet 53 through which the purge gas 44 is introduced is formed in the light path cover 50. In this manner, the light source device 1 can be manufactured. Note that, as will be described below, the steps of arranging the light path cover 80, arranging the transparent member 70, forming the inlet 83, and forming the target material 11 may further be included.

[0064] In the step of arranging the light path cover 80, the light path cover 80 is arranged so that one end 81 faces the target material 11 and the other end 82 passes through the laser light 13. In the step of arranging the transparent member 70, the transparent member 70 is arranged so that the other end 82 of the light path cover 80 is blocked by the transparent member 70 that transmits the laser light 13. In the step of forming the inlet 83, the inlet 83 for the purge gas 44 is formed in the light path cover 80. In the step of forming the target material 11, the gas 16 of the target material 11 is supplied from the supply port 22 to the supply space 23, and the supplied gas 16 of the target material 11 is solidified on the surface of the drum 10, thereby forming the target material 11.

[0065] Next, the effects of this embodiment will be described. The light source device 1 of this embodiment limits the diffusion range of the purge gas 44 and the gas 16 of the target material 11 using the exhaust case 40, the optical path cover 50, and the filter 60. This makes it possible to maintain the optical path through which the EUV light 15 passes in a high vacuum state, and to suppress absorption of the EUV light 15 by the purge gas 44 and the gas 16 of the target material 11. Therefore, it is possible to suppress a decrease in the amount of the EUV light 15.

[0066] Since purge gas 44 is ejected through optical path cover 50, which has a cone shape with a narrowing diameter from the opening at other end 52 toward the opening at one end 51, the flow rate of the gas ejected near target material 11 can be increased. As a result, the force pushing out debris is increased, and contamination of optical components such as collector mirror 30 can be suppressed. The same applies to optical path cover 80.

[0067] 8 to 11 are diagrams illustrating the flow of purge gas 44 in a light source 101 according to a comparative example. As shown in FIGS. 8 to 11, in the light source 101 according to the comparative example, the purge gas 44 is distributed in the optical paths of the laser beam 13 and the EUV light 15, reducing the amount of EUV light 15. In the light source 101 according to the comparative example, even if the positional relationship of the collector mirror 30, the flow system of the purge gas 44, and the pressure of the purge gas 44 are changed, the optical path through which the EUV light 15 passes cannot be maintained in a high vacuum state. In contrast, in the light source device 1 according to the present embodiment, the exhaust space 43 through which the purge gas 44 flows and the optical path space 46 through which the EUV light 15 passes can be separated, and therefore the optical path through which the EUV light 15 passes can be maintained in a high vacuum state.

[0068] <Embodiment 2> Next, a light source device according to a second embodiment will be described. In the light source device of this embodiment, the target material 11 is placed inside a crucible instead of being solidified on the surface of the drum 10. FIG. 12 is a cross-sectional view illustrating a light source device 2 according to the second embodiment. As shown in FIG. 12, the light source device 2 includes a crucible 90, a debris shield 93, a target material 11a, a collector mirror 30, an exhaust case 240, an optical path cover 50, a filter 60, a transparent member 70, and an optical path cover 80. The configurations of the collector mirror 30, the optical path cover 50, the filter 60, the transparent member 70, and the optical path cover 80 in the light source device 2 of the second embodiment are the same as those in the light source device 1 of the first embodiment.

[0069] The crucible 90 has a central axis C. The crucible 90 rotates about the central axis C as its axis of rotation. The crucible 90 is cylindrical and has an open end 91 and a closed other end 92. The crucible 90 is heated so that the target material 11a melts on its inner surface.

[0070] The target material 11a is liquid and is placed inside the crucible 90. The target material 11a spreads on the inner circumferential surface of the crucible 90 due to the centrifugal force of the rotation of the crucible 90. In this way, the target material 11a is formed by spreading the liquid target material 11a on the inner surface of the crucible 90.

[0071] The open end 91 of the crucible 90 is covered with a debris shield 93. The end 91 of the crucible 90 and the debris shield 93 are separated so as not to affect the rotation of the crucible 90. There is a small gap between the end 91 of the crucible 90 and the debris shield 93 to prevent leakage of the purge gas 44, but this is not limited to this. That is, the purge gas 44 may be discharged from between the end 91 of the crucible 90 and the debris shield 93. In this case, the exhaust case 240 includes an outer cover 241 provided on the outside of the cylindrical portion of the crucible 90, and the outer cover 241 may have at least one exhaust port 242 at a position facing the cylindrical portion of the crucible 90 (for example, a position facing the position of the gap through which the purge gas 44 leaks from the crucible 90). The debris shield 93 has an opening at a portion facing the irradiation position 17 of the target material 11a with the laser beam 13.

[0072] The exhaust case 240 has an outer cover 241 and an exhaust port 242. The outer cover 241 is disposed between the target material 11a and the collector mirror 30. The outer cover 241 may cover the debris shield 93. In this embodiment, the outer cover 241 has a rectangular shape that is open downward. The lower end of the outer cover 241 may be connected to the debris shield 93. The exhaust port 242 communicates with an exhaust space 243 that is formed on the target material 11a side of the outer cover 241.

[0073] The light path cover 50 is disposed between the target material 11a and the collector mirror 30. One end 51 of the light path cover 50 faces the target material 11a, and the other end 52 faces the collector mirror 30. The light path cover 50 is disposed to penetrate the outer cover 241. That is, one end 51 of the light path cover 50 protrudes further into the space on the target material 11a side than the outer cover 241. The other end 52 of the light path cover 50 protrudes further into the space on the collector mirror 30 side than the outer cover 241. The outer cover 241 and the debris shield 93 separate the exhaust space 243 in which the target material 11a is disposed from the light path space 46 in which the collector mirror 30 is disposed.

[0074] The inlet 53 of the optical path cover 50 is formed closer to the collector mirror 30 than the outer cover 241 in the optical path cover 50. The purge gas 44 introduced from the inlet 53 is ejected from one end 51 of the optical path cover 50 toward the target material 11a, passes through the exhaust space 243, and is exhausted from the exhaust port 242.

[0075] The optical path cover 80 is disposed between the target material 11a and the transmitting member 70. One end 81 of the optical path cover 80 faces the target material 11a, and the other end 82 faces the transmitting member 70. The optical path cover 80 is disposed to penetrate the debris shield 93. One end 81 of the optical path cover 80 is located in the space on the target material 11a side of the debris shield 93. The other end 82 of the optical path cover 80 protrudes into the space on the transmitting member 70 side of the debris shield 93. The outer cover 241 and the debris shield 93 separate the exhaust space 243 in which the target material 11a is disposed from the optical path space 46 in which the transmitting member 70 is disposed.

[0076] The inlet 83 of the optical path cover 80 is formed closer to the transmitting member 70 than the debris shield 93 on the optical path cover 80. The purge gas 44 introduced from the inlet 83 is ejected from one end 81 of the optical path cover 80 toward the target material 11a, passes through the exhaust space 243, and is exhausted from the exhaust port 242.

[0077] In the illumination method using the light source device 2 of this embodiment, in step S11 of preparing the light source device 2, the target material 11a is formed by spreading the liquid target material 11a on the inner circumferential surface of the crucible 90. Moreover, the manufacturing method of the light source device 2 of this embodiment further includes the step of spreading the liquid target material 11a on the inner circumferential surface of the crucible 90 to form the target material 11a.

[0078] According to this embodiment, the light source device 2 can use the liquid metal in the crucible 90 as the target material 11a, thereby expanding the options for the target material 11a. Other configurations and effects are included in the description of the first embodiment.

[0079] <Embodiment 3> Next, a light source device according to embodiment 3 will be described. The light source device of this embodiment differs from the light source device 1 of embodiment 1 in the positions of one end 51 and the other end 52 of the light path cover 50. In addition, the positions of one end 81 and the other end 82 of the light path cover 80 are also different.

[0080] FIG. 13 is a cross-sectional view illustrating a light source device 3 according to a third embodiment. As shown in FIG. 13, in the light source device 3, the light path cover 50 is arranged to contain the collector mirror 30 and the filter 60 therein. The light path cover 50 has a cone-shaped or hollow truncated cone-shaped portion, but is not limited thereto. For example, the light path cover 50 may include a portion whose diameter does not gradually increase from the opening at one end 51 toward the opening at the other end 52. Specifically, the light path cover 50 is cylindrical with an open one end 51 and an open other end 52, and may include a portion other than a cone-shaped or truncated cone-shaped portion as long as the cylindrical shape has an opening diameter at the other end 52 larger than that at the one end 51.

[0081] One end 51 of the light path cover 50 faces the target material 11. One end 51 of the light path cover 50 is connected to the outer cover 41. As such, in this embodiment, the light path cover 50 does not have to penetrate the outer cover 41. The other end 52 of the light path cover 50 is located closer to the collector mirror 30 than the outer cover 41. The other end 52 of the light path cover 50 is located in a direction away from the target material 11 than the collector mirror 30. In other words, the collector mirror 30 and the filter 60 are located inside the light path cover 50, and are located between the one end 51 and the other end 52. Note that the light path cover 50 may have an opening in a portion through which the reflected light reflected by the collector mirror 30 passes, or a transparent member that transmits the reflected light may be fitted into the portion through which the reflected light passes.

[0082] The filter 60 is disposed inside the light path cover 50 on the target material 11 side relative to the collector mirror 30. In this manner, the filter 60 of this embodiment does not need to be disposed so as to block the other end 52 of the light path cover 50.

[0083] Note that the positions of one end 51 and the other end 52 of the light path cover 50 in the above-described first embodiment and the positions of one end 51 and the other end 52 of the light path cover 50 in this embodiment may be combined as appropriate. That is, one end 51 of the light path cover 50 may be arranged closer to the target material 11 than the outer cover 41 so as to penetrate through the outer cover 41, or may be connected to the outer cover 41. In each case of the one end 51, the other end 52 may be connected to the filter 60 so as to be blocked by the filter 60, or may be arranged farther from the target material 11 than the collector mirror 30.

[0084] The light path cover 80 is arranged so as to contain the transparent member 70 (for example, at least one of the glass plate 70a and the condenser lens 70b) therein. The light path cover 80 has a cone-shaped or hollow truncated cone-shaped portion, but is not limited to this. For example, the light path cover 80 may include a portion whose diameter does not gradually increase from the opening at one end 81 toward the opening at the other end 82. Specifically, the light path cover 80 is cylindrical with one open end 81 and the other open end 82, and may include a portion other than a cone-shaped or truncated cone-shaped portion as long as the cylindrical shape has an opening diameter at the other end 82 larger than that at the one end 81.

[0085] One end 81 of the light path cover 80 faces the target material 11. One end 81 of the light path cover 80 is connected to the outer cover 41. As such, in this embodiment, the light path cover 80 does not have to penetrate the outer cover 41. The other end 82 of the light path cover 80 is arranged closer to the transparent member 70 than the outer cover 41. The other end 82 of the light path cover 80 is located in a direction away from the target material 11 than the transparent member 70. In other words, the transparent member 70 is arranged inside the light path cover 80, and is arranged between the one end 81 and the other end 82.

[0086] The glass plate 70a is disposed closer to the target material 11 than the condenser lens 70b inside the light path cover 80. In this manner, the transparent member 70 such as the glass plate 70a of the present embodiment does not need to be disposed so as to close the other end 82 of the light path cover 80.

[0087] The positions of one end 81 and the other end 82 of the optical path cover 80 in the above-described first embodiment and the positions of one end 81 and the other end 82 of the optical path cover 80 in this embodiment may be combined as appropriate. That is, one end 81 of the optical path cover 80 may be disposed closer to the target material 11 than the outer cover 41 so as to penetrate through the outer cover 41, or may be connected to the outer cover 41. In each case of the one end 81, the other end 82 may be connected to the transparent member 70 such as a glass plate 70a so as to be blocked by the transparent member 70, or may be disposed farther from the target material 11 than the transparent member 70.

[0088] Furthermore, the positions of one end 51 and the other end 52 of the light path cover 50 and the positions of one end 81 and the other end 82 of the light path cover 80 may be combined as appropriate.

[0089] Configurations other than those described above in embodiment 3, lighting methods using light source device 3 including configurations other than those described above, and manufacturing methods for light source device 3 including configurations other than those described above are included in the descriptions of embodiments 1 and 2.

[0090] <Embodiment 4> Next, a light source device according to embodiment 4 will be described. The light source device of this embodiment differs from the light source device 2 of embodiment 2 in the positions of one end 51 and the other end 52 of the light path cover 50. Also, the positions of one end 81 and the other end 82 of the light path cover 80 differ.

[0091] FIG. 14 is a cross-sectional view illustrating a light source device 4 according to a fourth embodiment. As shown in FIG. 14 , in the light source device 4, the light path cover 50 is arranged to contain the collector mirror 30 and the filter 60 therein. The light path cover 50 has a cone-shaped or hollow truncated cone-shaped portion, but is not limited thereto. For example, the light path cover 50 may include a portion whose diameter does not gradually increase from the opening at one end 51 toward the opening at the other end 52. Specifically, the light path cover 50 is cylindrical with an open one end 51 and an open other end 52, and may include a portion other than a cone shape or a truncated cone shape as long as the cylindrical shape has an opening diameter at the other end 52 larger than the opening diameter at the one end 51.

[0092] One end 51 of the light path cover 50 faces the target material 11a. One end 51 of the light path cover 50 is connected to the outer cover 241. As such, in this embodiment, the light path cover 50 does not have to penetrate the outer cover 241. The other end 52 of the light path cover 50 is located closer to the collector mirror 30 than the outer cover 241. The other end 52 of the light path cover 50 is located in a direction away from the target material 11a than the collector mirror 30. In other words, the collector mirror 30 and the filter 60 are located inside the light path cover 50, and are located between the one end 51 and the other end 52. Note that the light path cover 50 may have an opening in a portion through which the reflected light reflected by the collector mirror 30 passes, or a transparent member that transmits the reflected light may be fitted into the portion through which the reflected light passes.

[0093] The filter 60 is disposed inside the light path cover 50 on the target material 11a side relative to the collector mirror 30. In this manner, the filter 60 of the present embodiment does not need to be disposed so as to close the other end 52 of the light path cover 50.

[0094] Note that the positions of one end 51 and the other end 52 of the light path cover 50 in the second embodiment described above and the positions of one end 51 and the other end 52 of the light path cover 50 in this embodiment may be combined as appropriate. That is, one end 51 of the light path cover 50 may be disposed closer to the target material 11a than the outer cover 241 so as to penetrate through the outer cover 241, or may be connected to the outer cover 241. In each case of the one end 51, the other end 52 may be connected to the filter 60 so as to be blocked by the filter 60, or may be disposed farther from the target material 11a than the collector mirror 30.

[0095] The light path cover 80 is arranged so as to contain the transparent member 70 (for example, at least one of the glass plate 70a and the condenser lens 70b) therein. The light path cover 80 has a cone-shaped or hollow truncated cone-shaped portion, but is not limited to this. For example, the light path cover 80 may include a portion whose diameter does not gradually increase from the opening at one end 81 toward the opening at the other end 82. Specifically, the light path cover 80 is cylindrical with one open end 81 and the other open end 82, and may include a portion other than a cone-shaped or truncated cone-shaped portion as long as the cylindrical shape has an opening diameter at the other end 82 larger than that at the one end 81.

[0096] One end 81 of the light path cover 80 faces the target material 11a. One end 81 of the light path cover 80 penetrates the outer cover 241. As such, in this embodiment, one end 81 of the light path cover 80 does not have to be connected to the outer cover 241. The other end 82 of the light path cover 80 is disposed closer to the transparent member 70 than the outer cover 241. The other end 82 of the light path cover 80 is located in a direction farther away from the target material 11a than the transparent member 70. In other words, the transparent member 70 is disposed inside the light path cover 80, and is disposed between the one end 81 and the other end 82.

[0097] The glass plate 70a is disposed closer to the target material 11a than the condenser lens 70b inside the light path cover 80. In this manner, the transparent member 70 such as the glass plate 70a of the present embodiment does not need to be disposed so as to close the other end 82 of the light path cover 80.

[0098] Note that the positions of one end 81 and the other end 82 of the optical path cover 80 in the above-described first embodiment and the positions of one end 81 and the other end 82 of the optical path cover 80 in this embodiment may be combined as appropriate. That is, one end 81 of the optical path cover 80 may be disposed closer to the target material 11a than the outer cover 241 so as to penetrate through the outer cover 241, or may be connected to the outer cover 241. In each case of the one end 81, the other end 82 may be connected to the transparent member 70 such as a glass plate 70a so as to be blocked by the transparent member 70, or may be disposed farther from the target material 11a than the transparent member 70.

[0099] Furthermore, the positions of one end 51 and the other end 52 of the light path cover 50 and the positions of one end 81 and the other end 82 of the light path cover 80 may be combined as appropriate.

[0100] Configurations other than those described above in embodiment 4, illumination methods using light source device 4 including configurations other than those described above, and manufacturing methods for light source device 4 including configurations other than those described above are included in the descriptions of embodiments 1 to 3.

[0101] Although the embodiments of the present disclosure have been described above, the present disclosure includes appropriate modifications that do not impair the objects and advantages thereof, and is not limited to the above-described embodiments. The technical concept of the present disclosure also includes combinations of the configurations of the comparative example, and embodiments 1 and 2.

[0102] The following light source device, lighting method, and method for manufacturing a light source device are also included in the technical concept of the present disclosure.

[0103] (Appendix 1) a target material that generates EUV light together with plasma by irradiating it with laser light; a collector mirror that reflects the generated EUV light; an exhaust case having an exhaust port that is connected to an exhaust space formed on the target material side of the outer cover and disposed between the target material and the collector mirror; a cylindrical optical path cover having one open end and the other open end, the opening diameter of the one end being larger than the opening diameter of the other end, the diameter increasing from the opening of the one end toward the opening of the other end, the optical path cover being disposed to penetrate the outer cover so that the one end faces the target material on a side closer to the target material than the outer cover, and the other end faces the collector mirror on a side closer to the collector mirror than the outer cover; a filter that closes the other end of the optical path cover and transmits the EUV light; Equipped with a purge gas introduced from an inlet formed in the optical path cover is ejected from the one end of the optical path cover toward the target material, passes through the exhaust space, and is exhausted from the exhaust port; Light source device. (Appendix 2) a transparent member that transmits the laser light; a cylindrical laser beam path cover having one open end and another open end, the opening diameter of which is larger than the opening diameter of the one end, and the diameter of which increases from the opening of the one end toward the opening of the other end, the laser beam path cover being disposed such that the one end of the laser beam path cover faces the target material and the other end of the laser beam path cover faces the transparent member; Furthermore, the transparent member closes the other end of the laser optical path cover, the purge gas introduced from an inlet formed in the laser optical path cover is ejected from the one end of the laser optical path cover toward the target material, passes through the exhaust space, and is exhausted from the exhaust port. 10. The light source device of claim 1. (Appendix 3) a target material that generates EUV light together with plasma by irradiating it with laser light; a collector mirror that reflects the generated EUV light; an exhaust case having an exhaust port that is connected to an exhaust space formed on the target material side of the outer cover; and an outer cover that is disposed between the target material and the collector mirror. a cylindrical optical path cover having one open end and the other open end, the opening diameter of the one end being larger than the opening diameter of the other end, the diameter increasing from the opening of the one end toward the opening of the other end, the optical path cover being disposed to penetrate the outer cover so that the one end faces the target material on a side closer to the target material than the outer cover, and the other end faces the collector mirror on a side closer to the collector mirror than the outer cover; a filter that closes the other end of the optical path cover and transmits the EUV light; providing a light source device including: introducing a purge gas from an inlet formed in the optical path cover, ejecting the introduced purge gas from the one end of the optical path cover toward the target material, and exhausting the purge gas from the exhaust port through the exhaust space; generating the EUV light by irradiating the target material with the laser light; A lighting method comprising: (Appendix 4) The light source device is a transparent member that transmits laser light; a cylindrical laser beam path cover having one open end and another open end, the opening diameter of which is larger than the opening diameter of the one end, and the diameter of which increases from the opening of the one end toward the opening of the other end, the laser beam path cover being disposed such that the one end of the laser beam path cover faces the target material and the other end of the laser beam path cover faces the transparent member; further comprising In the step of exhausting air from the exhaust port, the purge gas is introduced from an inlet formed in the laser optical path cover, the introduced purge gas is ejected from the one end of the laser optical path cover toward the target material, and the purge gas is exhausted from the exhaust port through the exhaust space. 1. The illumination method described in Appendix 3. (Appendix 5) a target material that generates EUV light together with plasma by irradiating it with laser light; a collector mirror that reflects the generated EUV light; providing a light source comprising: disposing an outer cover between the target material and the collector mirror, and disposing an exhaust case by forming an exhaust port so as to communicate with an exhaust space formed on the target material side of the outer cover; a step of passing a cylindrical optical path cover through the outer cover, the cylindrical optical path cover having one open end and the other open end, the opening diameter of the one end being larger than the opening diameter of the other end, the diameter of the cylindrical optical path cover increasing from the opening of the one end toward the opening of the other end, the one end facing the target material on a side closer to the target material than the outer cover, and the other end facing the collector mirror on a side closer to the collector mirror than the outer cover; blocking the other end of the optical path cover with a filter that transmits the EUV light; forming an inlet in the optical path cover through which a purge gas is introduced; A method for manufacturing a light source device comprising: (Appendix 6) a step of disposing a cylindrical laser beam path cover having one open end and another open end, the opening diameter of which is larger than the opening diameter of the one end and which increases in diameter from the opening of the one end toward the opening of the other end, such that the one end of the laser beam path cover faces the target material and the other end of the laser beam path cover passes through; closing the other end of the laser optical path cover with the transparent member through which the laser light passes; forming an inlet through which the purge gas is introduced in the laser optical path cover; Equipped with A method for manufacturing the light source device described in Appendix 5.

[0104] This application claims priority based on Japanese Patent Application No. 2023-070595, filed on April 24, 2023, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0105] 1, 2, 3, 4 Light source device 10 drums 11, 11a Target material 12 Coolant 13 Laser light 14 Plasma 15 EUV light 16 Gas 17 Irradiation position 18 Debris 20 supply cases 21 Housing 22 Supply port 23 Supply space 24 Supply section 25 wiper 26 Vacuum seal 27 Inlet 28 Windows 30 Collector Mirror 40 Exhaust case 41 Outer cover 42 Exhaust port 43 Exhaust space 44 Purge gas 46 Optical path space 50 Optical path cover 51 one end 52 other end 53 Introduction 60 filters 70 Transparent member 70a Glass plate 70b Condenser lens 80 Optical path cover 81 one end 82 other end 83 entrance 90 Crucible 91 one end 92 other end 93 Debris Shield 101 Light source 240 Exhaust Case 241 Outer cover 242 Exhaust port 243 Exhaust space C center axis

Claims

1. a target material on the surface of the drum that generates EUV light together with plasma by irradiating the target material with laser light; a collector mirror that reflects the generated EUV light; an exhaust case having an exhaust port that is connected to an exhaust space formed on the target material side of the outer cover; and an outer cover that is disposed between the target material and the collector mirror. a cylindrical optical path cover having one open end and the other open end, the opening diameter of which is larger than the opening diameter of the other end, the one end facing the target material, and the other end being disposed closer to the collector mirror than the outer cover; a filter disposed at the other end of the optical path cover or within the optical path cover, the filter transmitting the EUV light; a supply case disposed inside the outer cover so as to be covered by the outer cover, the supply case having a supply port for supplying the target material gas to the surface of the drum; Equipped with a purge gas introduced from an inlet formed in the optical path cover is ejected from the one end of the optical path cover toward the target material, passes through the exhaust space, and is exhausted from the exhaust port; Light source device.

2. a target material on the surface of the drum that generates EUV light together with plasma by irradiating the target material with laser light; a collector mirror that reflects the generated EUV light; an exhaust case having an exhaust port that is connected to an exhaust space formed on the target material side of the outer cover; and an outer cover that is disposed between the target material and the collector mirror. a transparent member that transmits the laser light; a cylindrical laser beam path cover having one open end and another open end, the opening diameter of which is larger than the opening diameter of the other end, wherein the one end of the laser beam path cover faces the target material, and the transparent member is disposed at the other end of the laser beam path cover or within the laser beam path cover; a supply case disposed inside the outer cover so as to be covered by the outer cover, the supply case having a supply port for supplying the target material gas to the surface of the drum; Equipped with the purge gas introduced from an inlet formed in the laser optical path cover is ejected from the one end of the laser optical path cover toward the target material, passes through the exhaust space, and is exhausted from the exhaust port. Light source device.

3. the outer cover separates the exhaust space in which the target material is disposed from the optical path space in which the collector mirror is disposed; 3. The light source device according to claim 1.

4. a target material on the surface of the drum that generates EUV light together with plasma by irradiating the target material with laser light; a collector mirror that reflects the generated EUV light; an exhaust case having an exhaust port that is connected to an exhaust space formed on the target material side of the outer cover; and an outer cover that is disposed between the target material and the collector mirror. a cylindrical optical path cover having one open end and the other open end, the opening diameter of which is larger than the opening diameter of the other end, the one end facing the target material, and the other end being disposed closer to the collector mirror than the outer cover; a filter disposed at the other end of the optical path cover or within the optical path cover, the filter transmitting the EUV light; a supply case disposed inside the outer cover so as to be covered by the outer cover, the supply case having a supply port for supplying the target material gas to the surface of the drum; providing a light source device including: introducing a purge gas from an inlet formed in the optical path cover, ejecting the introduced purge gas from the one end of the optical path cover toward the target material, and exhausting the purge gas from the exhaust port through the exhaust space; generating the EUV light by irradiating the target material with the laser light; A lighting method comprising:

5. a target material on the surface of the drum that generates EUV light together with plasma by irradiating the target material with laser light; a collector mirror that reflects the generated EUV light; an exhaust case having an exhaust port that is connected to an exhaust space formed on the target material side of the outer cover; and an outer cover that is disposed between the target material and the collector mirror. a transparent member that transmits the laser light; a cylindrical laser beam path cover having one open end and another open end, the opening diameter of which is larger than the opening diameter of the other end, wherein the one end of the laser beam path cover faces the target material, and the transparent member is disposed at the other end of the laser beam path cover or within the laser beam path cover; a supply case disposed inside the outer cover so as to be covered by the outer cover, the supply case having a supply port for supplying the target material gas to the surface of the drum; providing a light source device including: introducing a purge gas from an inlet formed in the laser optical path cover, ejecting the introduced purge gas from the one end of the laser optical path cover toward the target material, and exhausting the purge gas from the exhaust port through the exhaust space; generating the EUV light by irradiating the target material with the laser light; A lighting method comprising:

6. the outer cover separates the exhaust space in which the target material is disposed from the optical path space in which the collector mirror is disposed; 6. The lighting method according to claim 4 or 5.

7. a target material on the surface of the drum that generates EUV light together with plasma by irradiating the target material with laser light; a collector mirror that reflects the generated EUV light; providing a light source comprising: disposing an outer cover between the target material and the collector mirror, and disposing an exhaust case by forming an exhaust port so as to communicate with an exhaust space formed on the target material side of the outer cover; a supply case disposed inside the outer cover so as to be covered by the outer cover, the supply case having a supply port for supplying the target material gas to the surface of the drum; a step of disposing a cylindrical optical path cover having one open end and the other open end, the opening diameter of which is larger than that of the one end, such that the one end faces the target material and the other end is closer to the collector mirror than the outer cover; disposing a filter that transmits the EUV light at the other end of the optical path cover or within the optical path cover; forming an inlet in the optical path cover through which a purge gas is introduced; A method for manufacturing a light source device comprising:

8. a target material on the surface of the drum that generates EUV light together with plasma by irradiating the target material with laser light; a collector mirror that reflects the generated EUV light; providing a light source comprising: disposing an outer cover between the target material and the collector mirror, and disposing an exhaust case by forming an exhaust port so as to communicate with an exhaust space formed on the target material side of the outer cover; a supply case disposed inside the outer cover so as to be covered by the outer cover, the supply case having a supply port for supplying the target material gas to the surface of the drum; a step of disposing a cylindrical laser beam path cover having one open end and another open end, the opening diameter of which is larger than that of the one end, such that the one end of the laser beam path cover faces the target material and the other end of the laser beam path cover allows the laser beam to pass through; disposing a transparent member through which the laser light passes at the other end of the laser path cover or within the laser path cover; forming an inlet through which a purge gas is introduced in the laser optical path cover; A method for manufacturing a light source device comprising:

9. the outer cover is arranged to separate the exhaust space in which the target material is arranged from the optical path space in which the collector mirror is arranged. A method for manufacturing the light source device according to claim 7 or 8.

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