Light source device, illumination method, and method for manufacturing 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, a lighting method, and a method for manufacturing a light source device.

Background Art

[0002] Non-Patent Documents 1 to 3 disclose light sources that irradiate a target material containing xenon formed on the surface of a rotating drum with laser light to generate EUV light from the generated plasma.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Summary of the Invention

[0004] As a method for generating EUV light, in addition to Non-Patent Documents 1 to 3 described above, there is also a method of putting a liquid molten metal containing tin into a container such as a crucible and rotating it, irradiating the molten metal with laser light, and generating EUV light from the plasma generated. In any method, debris formed from target materials such as xenon, tin, and lithium during plasma generation deteriorates optical elements such as mirrors. This has become a serious problem in EUV light sources.

[0005] So far, methods have been proposed to suppress debris by flowing an inert gas in the optical path of the laser light or near the mirror. However, due to the diffused inert gas and the gasified target material, EUV light is absorbed, and the amount of EUV light decreases due to the fact that the formation of debris is not sufficiently suppressed and contamination of the optical element still occurs. This has been an issue.

[0006] The present disclosure has been made to solve such problems, and provides a light source device, a lighting method, and a method for manufacturing a light source device capable of suppressing a decrease in the amount of EUV light.

[0007] A light source device according to one aspect of the present embodiment includes a target material that generates EUV light together with plasma by irradiating laser light, 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 communicating with an exhaust space formed on the target material side of the outer cover. The light source device further includes an optical path cover having an open one end and an open other end, the opening diameter of the other end being larger than that of the one end, the one end facing the target material, and the other end being disposed 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 and transmitting the EUV light. The 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 and exhausted from the exhaust port through the exhaust space.

[0008] A light source device according to one aspect of the present embodiment includes a target material that generates EUV light together with plasma by irradiating laser light, 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 communicating with an exhaust space formed on the target material side of the outer cover, a transmission member that transmits the laser light, and a laser optical path cover having an open one end and an open other end, the opening diameter of the other end being larger than that of the one end, the one end of the laser optical path cover facing the target material, and the transmission member being disposed at the other end of the laser optical path cover or within 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 and exhausted from the exhaust port through the exhaust space.

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

[0010] In the above-described light source device, a cylindrical drum that rotates about a 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 at a portion facing the irradiation position of the laser light, and a supply case having a supply port communicating with a supply space formed on the target material side with respect to the housing. The gas of the target material supplied from the supply port may be solidified on the surface of the drum to form the target material.

[0011] In the above-described light source device, a cylindrical crucible that rotates about a central axis as a rotation axis and has an open one end and a closed other end, the crucible being heated so that the target material melts on its inner surface, and a debris shield having an opening at a portion facing the irradiation position of the laser light. The target material may be formed by spreading the liquid target material on the inner peripheral surface of the crucible.

[0012] An illumination method according to an aspect of the present embodiment includes a target material that generates EUV light together with plasma by irradiating laser light, 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 communicating with an exhaust space formed on the target material side with respect to the outer cover. A cylindrical optical path cover having an open one end and an open other end, wherein the opening diameter of the other end is larger than the opening diameter of the one end, the one end facing the target material, and the other end being disposed on the collector mirror side with respect to the outer cover. The optical path cover, and a filter disposed at the other end of the optical path cover or inside the optical path cover and transmitting the EUV light. Preparing 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; and irradiating the target material with the laser light to generate the EUV light.

[0013] An illumination method according to an aspect of the present embodiment includes a target material that generates EUV light together with plasma by irradiating laser light, 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 communicates with an exhaust space formed closer to the target material side than the outer cover, a transmission member that transmits the laser light, and a cylindrical laser optical path cover having an open one end and an open other end, wherein the opening diameter of the other end is larger than the opening diameter of the one end, and the one end of the laser optical path cover faces the target material, and the transmission member is disposed at the other end of the laser optical path cover or within the laser optical path cover. The method includes the steps of preparing a light source device including the laser optical path cover, 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, and irradiating the target material with the laser light to generate the EUV light.

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

[0015] In the above illumination method, the light source device further includes a cylindrical drum that rotates about a central axis as a rotation axis, the drum being cooled so that the target material is solidified on the surface, a housing having an opening at a portion facing the irradiation position of the laser light, and a supply case having a supply port that communicates with a supply space formed closer to the target material side than the housing. In the step of preparing the light source device, the gas of the target material may be supplied from the supply port to the supply space, and the target material may be formed by solidifying the supplied gas of the target material on the surface of the drum.

[0016] In the above lighting method, the light source device is a cylindrical crucible that rotates about a central axis as a rotation axis and has an open one end and a closed other end, and the crucible is heated so that the target material melts on the inner surface. The light source device further includes a debris shield having an opening at a portion facing the irradiation position of the laser beam. In the step of preparing the light source device, the target material may be formed by spreading the liquid target material on the inner peripheral surface of the crucible.

[0017] A method for manufacturing a light source device according to an aspect of the present embodiment includes a step of preparing a light source including a target material that generates EUV light together with plasma by irradiating a laser beam, and a collector mirror that reflects the generated EUV light; a step of 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 disposing a cylindrical optical path cover having an open one end and an open other end, and having a larger opening diameter at the other end than at the one end, such that the one end faces the target material and the other end is on the collector mirror side of the outer cover; a step of disposing a filter that transmits the EUV light at the other end of the optical path cover or inside the optical path cover; and a step of forming an inlet through which a purge gas is introduced into the optical path cover.

[0018] A method for manufacturing a light source device according to an aspect of the present embodiment includes a step of preparing a light source including a target material that generates EUV light together with plasma by irradiating laser light, and a collector mirror that reflects the generated EUV light; a step of 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 disposing a cylindrical laser optical path cover having an open one end and an open other end, and having a larger opening diameter at the other end than at the one end, such that the one end of the laser optical path cover faces the target material and the other end of the laser optical path cover allows the laser light to pass through; a step of disposing a transmissive member through which the laser light passes at the other end of the laser optical path cover or within the laser optical path cover; and a step of forming an inlet through which a purge gas is introduced into the laser optical path cover.

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

[0020] In the above method for manufacturing a light source device, the light source may further include a cylindrical drum that rotates about a central axis as a rotation axis, the drum being cooled such that the target material is solidified on the surface thereof, a housing having an opening at a portion facing the irradiation position of the laser light, and a supply case having a supply port that communicates with a supply space formed on the target material side of the housing, and may further include a step of 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 to form the target material.

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

[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 Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Mode for Carrying Out 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, those denoted by the same reference numerals indicate substantially the same content.

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

[0026] <Comparative Example> FIG. 1 is a perspective view illustrating the light source 101 according to the comparative example. FIG. 2 is a cross-sectional view illustrating the light source 101 according to the comparative example, schematically showing the cross-section taken along line II-II of FIG. 1. FIG. 3 is a cross-sectional view illustrating the light source 101 according to the comparative example, schematically showing the cross-section taken along line III-III of FIG. 1. Note that some reference numerals and some hatching are omitted so that the drawings do not become complicated.

[0027] As shown in FIGS. 1 to 3, the 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. Further, the supply case 20 may further have 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 about the central axis C as the rotation axis. Also, the drum 10 may move in the direction of the central axis C.

[0029] Here, for the sake of convenience in explaining the light source 101, an XYZ orthogonal coordinate axis system is introduced. The direction in which the central axis C of the drum 10 extends is defined as the Z-axis direction. The plane orthogonal to the central axis C of the drum 10 is defined as the XY plane. For example, the +Z-axis direction is upward and the -Z-axis direction is downward. Note that the upward and downward directions are for the convenience of explaining the light source 101 and do not indicate the actual direction in which the light source 101 is arranged.

[0030] The drum 10 contains, for example, copper as a material. A coolant 12 such as liquid nitrogen is supplied inside the drum 10. Therefore, the drum 10 is cooled so that the target material 11 solidifies 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 temperature of the surface of the drum 10 can be made below the freezing point of the target material 11.

[0031] The target material 11 generates EUV light 15 together with plasma 14 by being irradiated with laser light 13. The target material 11 is formed on the surface of the drum 10. The target material 11 contains, for example, xenon (Xe). Note that the target material 11 is not limited to xenon and may contain tin (Sn), lithium (Li), etc., as long as it can generate EUV light 15 together with plasma 14 by being 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 with a hollow interior. The drum 10 is disposed inside the housing 21. The drum 10 rotates inside the housing 21. A portion of the housing 21 facing the irradiation position 17 of the laser beam 13 is open. Thus, 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 on the target material 11 side with respect to the housing 21. The space formed on the target material 11 side with respect to the housing 21 is called a supply space 23.

[0033] The supply port 22 communicates with the supply space 23. Further, the supply port 22 is connected to a supply portion 24 of the gas 16 for the target material 11. The supply portion 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. Thereby, plasma 14 is generated from the target material 11. Thus, 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. Thus, the irradiation position 17 of the laser beam 13 is always the non-irradiated target material 11 of the laser beam 13.

[0035] The laser beam 13 may irradiate the target material 11 through a transmission member 70 such as a condenser lens and a window 28. The wiper 25 may shape the target material 11 solidified on the surface of the drum 10. The vacuum seal 26 seals the inside of the light source 101. The injection port 27 communicates with the inside of the drum 10. Liquid nitrogen is injected into the inside of the drum 10 through the injection port 27.

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

[0037] Therefore, in order to suppress the adhesion of the debris 18 to the optical element, a purge gas 44 containing an inert gas or the like may be flowed in the optical path of the laser light 13 and in the vicinity of the optical element to suppress the adhesion of the debris 18. The purge gas 44 may contain, for example, at least any one of argon (Ar), helium (He), nitrogen (N2), and hydrogen (H2), or may contain gases other than these. However, there is a problem 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 the EUV light 15. In addition, there is a problem that the generated debris 18 is not sufficiently suppressed, and the optical element still deteriorates, reducing the amount of the EUV light 15.

[0038] <Embodiment 1> Next, the light source device according to Embodiment 1 will be described. The light source device according to the present 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 in a high vacuum, suppressing the absorption of the EUV light 15 by the purge gas 44 or the like, and improving the removal effect of the debris 18.

[0039] FIG. 5 is a cross-sectional view illustrating the light source device 1 according to Embodiment 1. As shown in FIG. 5, the light source device 1 of the present embodiment includes a drum 10, a target material 11, a supply case 20, a collector mirror 30, an exhaust case 40, an optical path cover 50, a filter 60, a transmission member 70, and an optical 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 the same as 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 to, for example, the illumination optical system of the inspection apparatus. Thereby, the inspection apparatus can use the EUV light 15 as inspection light. Note that the collector mirror 30 is not limited to the inspection apparatus, and may reflect the EUV light 15 to other optical apparatuses such as an exposure apparatus.

[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 the present embodiment, the outer cover 41 has a cylindrical shape with a hollow interior. The supply case 20 is disposed inside the outer cover 41. The outer cover 41 forms a space on the target material 11 side rather than the outer cover 41. The space formed on the target material 11 side rather than the outer cover 41 is referred to as an exhaust space 43.

[0042] The exhaust port 42 communicates with the exhaust space 43. Further, the exhaust port 42 may be connected to an exhaust pump. Thereby, the exhaust space 43 can be exhausted through the exhaust port 42.

[0043] The optical path cover 50 is disposed between the target material 11 and the collector mirror 30. The optical path cover 50 has a cone shape or a truncated cone shape with a hollow interior. Specifically, the optical path cover 50 is a cylindrical shape having 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. One end 51 of the optical path cover 50 faces the target material 11 on the target material 11 side rather than the outer cover 41. The other end 52 of the optical path cover 50 is disposed to face the collector mirror 30 on the collector mirror 30 side rather than the outer cover 41.

[0044] The optical path cover 50 is disposed to penetrate the outer cover 41. That is, one end 51 of the optical path cover 50 protrudes into the exhaust space 43 on the target material 11 side with respect to the outer cover 41. The other end 52 of the optical path cover 50 protrudes into the space on the collector mirror 30 side with respect to the outer cover 41. The space on the collector mirror 30 side with respect to the outer cover 41 is called the 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 and the optical path space 46 in which the collector mirror 30 is disposed. The optical path space 46 is preferably maintained in a high vacuum state by an exhaust pump such as a vacuum pump.

[0045] The filter 60 is disposed so as to block the other end 52 of the optical path cover 50. The filter 60 transmits the EUV light 15. An inlet 53 for introducing the purge gas 44 is formed in the optical path cover 50. For example, the inlet 53 is formed on the collector mirror 30 side with respect to the outer cover 41 in the optical path cover 50. The purge gas 44 introduced from the inlet 53 is jetted from one end 51 of the optical path cover 50 toward the target material 11, and is exhausted from the exhaust port 42 through the exhaust space 43.

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

[0047] The optical path cover 80 is disposed between the target material 11 and the transmission member 70. The optical path cover 80 is also referred to as a laser optical path member. The optical path cover 80 has a cone shape or a truncated cone shape with a cavity inside. Specifically, the optical path cover 80 is in a cylindrical shape having an open end 81 and an open other end 82, but the opening diameter of the other end 82 is larger than that of the open end 81, and it is in a cylindrical shape with an increasing diameter from the opening of the end 81 toward the opening of the other end 82. One end 81 of the optical path cover 80 faces the target material 11, and the other end 82 is disposed to face the transmission member 70.

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

[0049] The transmission member 70 is disposed 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 in the optical path cover 80 on the transmission member 70 side rather 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 and exhausted from the exhaust port 42 through the exhaust space 43.

[0050] Thus, the light source device 1 of this embodiment surrounds the periphery of the target material 11 with the exhaust case 40, and separates the optical path space 46 where the EUV light 15 and the laser light 13 are arranged from the exhaust space 43 where the target material 11 is arranged. Further, the other end 52 of the optical path cover 50 is sealed with the filter 60, and the other end 82 of the optical path cover 80 is sealed with the transmission member 70. By adopting such a configuration, a flow of purge gas 44 such as an inert gas (Ar, He, N2, and H2) is formed from one end 81 of the optical path cover 80 which is the incident port of the laser light 13 and one end 51 of the optical path cover 50 which is the emission port of the EUV light 15 toward the exhaust port 42. Therefore, the range where the gas pressure is high, such as the purge gas 44, can be limited, and the effect of removing debris 18 can be improved.

[0051] Furthermore, by forming the optical path cover 50 and the optical path cover 80 into a cone shape whose diameter becomes smaller toward one end 51 and one end 81, respectively, the gas pressure and the gas flow velocity at one end 51 and one end 81 can be efficiently increased, and the effect of removing debris 18 can be improved.

[0052] Next, as the operation of this embodiment, an illumination method using the light source device 1 will be described. FIG. 6 is a flowchart 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 of preparing the light source device 1 (S11), a step of ejecting the purge gas 44 (S12), and a step of generating the EUV light 15 (S13).

[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. Further, the light source device 1 may further include a drum 10, a supply case 20, a transmission 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 target material 11 may be formed by solidifying the supplied gas 16 of the target material 11 on the surface of the drum 10.

[0055] Next, as shown in step S12, 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 port 42 through the exhaust space 43.

[0056] In step S12, the purge gas 44 may be introduced from the 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 the exhaust port 42 through the exhaust space 43.

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

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

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

[0060] Next, as shown in step S22, arrange an exhaust case 40. Specifically, arrange an outer cover 41 between the target material 11 and the collector mirror 30. Then, form an exhaust port 42 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. In this way, the exhaust case 40 is arranged. 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. Thereby, it is possible to suppress a reduction in the light quantity of the EUV light 15 due to the purge gas 44 and the gas 16 of the target material 11.

[0061] Next, as shown in step S23, arrange an optical path cover 50. Specifically, arrange the optical path cover 50 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 through the outer cover 41.

[0062] Next, as shown in step S24, arrange a filter 60. Specifically, arrange the filter 60 so as to block the other end 52 of the optical path cover 50 with the filter 60 that transmits the EUV light 15.

[0063] Next, as shown in step S25, form an inlet 53 through which the purge gas 44 is introduced into the optical path cover 50. In this way, the light source device 1 can be manufactured. Note that, as shown below, it may further include steps of arranging an optical path cover 80, arranging a transmission member 70, forming an inlet 83, and forming a target material 11.

[0064] In the step of disposing the optical path cover 80, the optical path cover 80 is disposed such that one end 81 faces the target material 11 and the other end 82 allows the laser beam 13 to pass through. In the step of disposing the transmission member 70, the transmission member 70 is disposed so as to block the other end 82 of the optical path cover 80 with the transmission member 70 through which the laser beam 13 passes. In the step of forming the inlet 83, an inlet 83 for the purge gas 44 is formed in the optical 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 gas 16 of the supplied target material 11 is solidified on the surface of the drum 10, thereby forming the target material 11.

[0065] Next, the effects of the present embodiment will be described. The light source device 1 of the present embodiment limits the diffusion range of the purge gas 44 and the gas 16 of the target material 11 by using the exhaust case 40, the optical path cover 50, and the filter 60. As a result, the optical path through which the EUV light 15 passes can be maintained in a high vacuum state, and absorption of the EUV light 15 by the purge gas 44 and the gas 16 of the target material 11 can be suppressed. Therefore, a decrease in the light amount of the EUV light 15 can be suppressed.

[0066] Since the purge gas 44 is ejected through the conical optical path cover 50 whose diameter is reduced from the opening of the other end 52 toward the opening of the one end 51, the flow velocity of the gas ejected near the target material 11 can be increased. As a result, the force for pushing out debris can be increased, and contamination of optical members such as the collector mirror 30 can be suppressed. The same applies to the optical path cover 80.

[0067] Figures 8 to 11 are diagrams illustrating the flow of the purge gas 44 in the light source 101 according to the comparative example. As shown in Figures 8 to 11, in the light source 101 of the comparative example, the purge gas 44 is distributed in the optical paths of the laser beam 13 and the EUV light 15, and the amount of the EUV light 15 is reduced. In the light source 101 of the comparative example, even if the positional relationship of the collector mirror 30, the flow system of the purge gas 44, and each condition of 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. On the other hand, since the light source device 1 of the present embodiment can separate the exhaust space 43 through which the purge gas 44 flows and the optical path space 46 through which the EUV light 15 passes, the optical path through which the EUV light 15 passes can be maintained in a high vacuum state.

[0068] <Embodiment 2> Next, the light source device according to Embodiment 2 will be described. In the light source device of the present embodiment, instead of being solidified on the surface of the drum 10, the target material 11 is disposed inside the crucible. FIG. 12 is a cross-sectional view illustrating the light source device 2 according to Embodiment 2. 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 transmission member 70, and an optical path cover 80. The configurations of the collector mirror 30, the optical path cover 50, the filter 60, the transmission member 70, and the optical path cover 80 in the light source device 2 of Embodiment 2 are the same as those in the light source device 1 of Embodiment 1.

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

[0070] The target material 11a is liquid and is disposed inside the crucible 90. The target material 11a spreads over the inner peripheral 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 over the inner surface of the crucible 90.

[0071] One open end 91 of the crucible 90 is covered by a debris shield 93. One 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 slight gap between one end 91 of the crucible 90 and the debris shield 93 such that purge gas 44 does not leak, but it is not limited to this. That is, the purge gas 44 may be discharged from between one end 91 of the crucible 90 and the debris shield 93. In this case, the exhaust case 240 includes an outer cover 241 provided outside 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 from which the purge gas 44 leaks out of the crucible 90). The debris shield 93 has an opening at a portion facing the irradiation position 17 of the laser beam 13 on the target material 11a.

[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 the present embodiment, the outer cover 241 has a rectangular shape with an open bottom. 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 formed on the target material 11a side of the outer cover 241.

[0073] The optical path cover 50 is disposed between the target material 11a and the collector mirror 30. One end 51 of the optical path cover 50 faces the target material 11a, and the other end 52 is disposed so as to face the collector mirror 30. The optical path cover 50 is disposed through the outer cover 241. That is, one end 51 of the optical path cover 50 protrudes into the space on the target material 11a side of the outer cover 241. The other end 52 of the optical path cover 50 protrudes into the space on the collector mirror 30 side of 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 optical path space 46 in which the collector mirror 30 is disposed.

[0074] The inlet 53 of the optical path cover 50 is formed on the collector mirror 30 side of 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, and is exhausted from the exhaust port 242 through the exhaust space 243.

[0075] The optical path cover 80 is disposed between the target material 11a and the transmission member 70. One end 81 of the optical path cover 80 faces the target material 11a, and the other end 82 is disposed to face the transmission member 70. The optical path cover 80 is disposed through 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 transmission 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 transmission member 70 is disposed.

[0076] The inlet 83 of the optical path cover 80 is formed on the transmission member 70 side of the debris shield 93 in 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, and is exhausted from the exhaust port 242 through the exhaust space 243.

[0077] In the lighting method using the light source device 2 of the present 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 peripheral surface of the crucible 90. Further, the manufacturing method of the light source device 2 of the present embodiment further includes a step of forming the target material 11a by spreading the liquid target material 11a on the inner peripheral surface of the crucible 90.

[0078] According to this embodiment, since the light source device 2 can use the liquid metal in the crucible 90 as the target material 11a, the options for the target material 11a can be expanded. Other configurations and effects are included in the description of Embodiment 1.

[0079] <Embodiment 3> Next, the light source device according to Embodiment 3 will be described. The light source device of this embodiment has different positions of one end 51 and the other end 52 of the optical path cover 50 compared to the light source device 1 of Embodiment 1. Also, the positions of one end 81 and the other end 82 of the optical path cover 80 are different.

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

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

[0082] The filter 60 is disposed closer to the target material 11 side than the collector mirror 30 inside the optical path cover 50. Thus, the filter 60 of the present embodiment does not have to be disposed so as to close the other end 52 of the optical path cover 50.

[0083] Note that the positions of one end 51 and the other end 52 of the optical path cover 50 in the aforementioned Embodiment 1 and the positions of one end 51 and the other end 52 of the optical path cover 50 in the present embodiment may be appropriately combined. That is, one end 51 of the optical path cover 50 may be disposed closer to the target material 11 side than the outer cover 41 so as to penetrate the outer cover 41, or may be connected to the outer cover 41. In each case of 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 so as to be farther from the target material 11 than the collector mirror 30.

[0084] The optical path cover 80 is disposed so as to include a transmission member 70 (for example, at least one of a glass plate 70a and a condenser lens 70b) inside. The optical path cover 80 has a conical shape or a truncated conical shape with a hollow inside, but is not limited thereto. For example, the optical path cover 80 may include a portion where the diameter does not gradually increase from the opening of one end 81 to the opening of the other end 82. Specifically, the optical path cover 80 is in a cylindrical shape having an open one end 81 and an open other end 82, and may include a portion other than a conical shape and a truncated conical shape as long as the opening diameter of the other end 82 is larger than the opening diameter of one end 81.

[0085] One end 81 of the optical path cover 80 faces the target material 11. One end 81 of the optical path cover 80 is connected to the outer cover 41. Thus, in the present embodiment, the optical path cover 80 does not have to penetrate the outer cover 41. The other end 82 of the optical path cover 80 is disposed on the side of the transmissive member 70 rather than the outer cover 41. The other end 82 of the optical path cover 80 is located in a direction away from the target material 11 rather than the transmissive member 70. That is, the transmissive member 70 is disposed inside the optical path cover 80 and between the one end 81 and the other end 82.

[0086] The glass plate 70a is disposed on the side of the target material 11 rather than the condenser lens 70b inside the optical path cover 80. Thus, the transmissive member 70 such as the glass plate 70a of the present embodiment does not have to be disposed so as to close the other end 82 of the optical path cover 80.

[0087] Note that the positions of the one end 81 and the other end 82 of the optical path cover 80 in the foregoing Embodiment 1 and the positions of the one end 81 and the other end 82 of the optical path cover 80 in the present embodiment may be appropriately combined. That is, the one end 81 of the optical path cover 80 may be disposed on the side of the target material 11 rather than the outer cover 41 so as to penetrate 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 transmissive member 70 so as to be blocked by the transmissive member 70 such as the glass plate 70a, or may be disposed in a direction away from the target material 11 rather than the transmissive member 70.

[0088] Also, the positions of the one end 51 and the other end 52 of the optical path cover 50 and the positions of the one end 81 and the other end 82 of the optical path cover 80 may be appropriately combined.

[0089] Configurations other than the above-described configurations in Embodiment 3, an illumination method using the light source device 3 including configurations other than the above-described configurations, and a manufacturing method of the light source device 3 including configurations other than the above-described configurations are included in the descriptions of Embodiments 1 and 2.

[0090] <Embodiment 4> Next, the light source device according to Embodiment 4 will be described. The light source device of this embodiment has different positions of one end 51 and the other end 52 of the optical path cover 50 compared to the light source device 2 of Embodiment 2. Also, the positions of one end 81 and the other end 82 of the optical path cover 80 are different.

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

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

[0093] The filter 60 is arranged on the side of the target material 11a rather than the collector mirror 30 inside the optical path cover 50. Thus, the filter 60 of this embodiment does not have to be arranged so as to block the other end 52 of the optical path cover 50.

[0094] In addition, the positions of the one end 51 and the other end 52 of the optical path cover 50 in the foregoing Embodiment 2 and the positions of the one end 51 and the other end 52 of the optical path cover 50 in the present embodiment may be appropriately combined. That is, the one end 51 of the optical path cover 50 may be disposed closer to the target material 11a side than the outer cover 241 so as to penetrate 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 so as to be farther from the target material 11a than the collector mirror 30.

[0095] The optical path cover 80 is disposed so as to include a transmissive member 70 (for example, at least one of a glass plate 70a and a condenser lens 70b) therein. The optical path cover 80 has a cone shape or a frustum of a cone shape with a hollow interior, but is not limited thereto. For example, the optical path cover 80 may include a portion where the diameter does not gradually increase from the opening of the one end 81 to the opening of the other end 82. Specifically, the optical path cover 80 is a cylindrical shape having an open one end 81 and an open other end 82, and may include a portion other than the cone shape and the frustum of a cone shape as long as the opening diameter of the other end 82 is larger than the opening diameter of the one end 81.

[0096] The one end 81 of the optical path cover 80 faces the target material 11a. The one end 81 of the optical path cover 80 penetrates the outer cover 241. Thus, in the present embodiment, the one end 81 of the optical path cover 80 does not have to be connected to the outer cover 241. The other end 82 of the optical path cover 80 is disposed closer to the transmissive member 70 side than the outer cover 241. The other end 82 of the optical path cover 80 is located in a direction farther from the target material 11a than the transmissive member 70. That is, the transmissive member 70 is disposed inside the optical path cover 80 and between the one end 81 and the other end 82.

[0097] The glass plate 70a is disposed on the target material 11a side rather than the condenser lens 70b inside the optical path cover 80. Thus, the transmission member 70 such as the glass plate 70a in the present embodiment does not have to be disposed so as to block the other end 82 of the optical path cover 80.

[0098] In addition, the positions of one end 81 and the other end 82 of the optical path cover 80 in the aforementioned Embodiment 1 and the positions of one end 81 and the other end 82 of the optical path cover 80 in the present embodiment may be appropriately combined. That is, one end 81 of the optical path cover 80 may be disposed on the target material 11a side rather than the outer cover 241 so as to penetrate the outer cover 241, or may be connected to the outer cover 241. In each case of one end 81, the other end 82 may be connected to the transmission member 70 so as to be blocked by the transmission member 70 such as the glass plate 70a, or may be disposed so as to be away from the target material 11a rather than the transmission member 70.

[0099] Also, the positions of one end 51 and the other end 52 of the optical path cover 50 and the positions of one end 81 and the other end 82 of the optical path cover 80 may be appropriately combined.

[0100] The configurations other than the above-described configurations in Embodiment 4, the lighting method using the light source device 4 including the configurations other than the above-described configurations, and the manufacturing method of the light source device 4 including the configurations other than the above-described configurations are included in the descriptions of Embodiments 1 to 3.

[0101] As described above, the embodiments of the present disclosure have been described. However, the present disclosure includes appropriate modifications that do not impair its object and advantages, and furthermore, is not limited by the above-described embodiments. The combinations of the configurations of the comparative example, Embodiments 1 and 2 are also included in the technical idea of the present disclosure.

[0102] Also, the following light source device, lighting method, and manufacturing method of the light source device are also included in the technical idea of the present disclosure.

[0103] (Appendix 1) A target material that generates EUV light together with plasma by irradiating laser light, 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 communicating with an exhaust space formed closer to the target material side than the outer cover; An optical path cover having an open one end and an open other end, the opening diameter of the other end being larger than that of the one end, and having a cylindrical shape in which the diameter increases from the opening of the one end toward the opening of the other end, the one end facing the target material on the target material side with respect to the outer cover, and the other end penetrating the outer cover and facing the collector mirror on the collector mirror side with respect to the outer cover; A filter that closes the other end of the optical path cover and transmits the EUV light; Comprising; The purge gas introduced from the inlet formed in the optical path cover is jetted from the one end of the optical path cover toward the target material, and exhausted from the exhaust port through the exhaust space. A light source device. (Appendix 2) A transmission member that transmits the laser light; A laser optical path cover having an open one end and an open other end, the opening diameter of the other end being larger than that of the one end, and having a cylindrical shape in which the diameter increases from the opening of the one end toward the opening of the other end, the one end of the laser optical path cover facing the target material, and the other end of the laser optical path cover facing the transmission member; Further comprising; The transmission member closes the other end of the laser optical path cover. The purge gas introduced from the inlet formed in the laser optical path cover is jetted from the one end of the laser optical path cover toward the target material, and exhausted from the exhaust port through the exhaust space. The light source device according to Appendix 1. (Appendix 3) A target material that generates EUV light together with plasma by irradiating laser light; 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 communicating with an exhaust space formed closer to the target material side than the outer cover; an optical path cover having an open one end and an open other end, the opening diameter of the other end being larger than that of the one end, and having a cylindrical shape in which the diameter increases from the opening of the one end toward the opening of the other end, the one end facing the target material on the target material side with respect to the outer cover, and the other end penetrating the outer cover and facing the collector mirror on the collector mirror side with respect to the outer cover; a filter that closes the other end of the optical path cover and transmits the EUV light; preparing a light source device including the above; introducing a purge gas from an introduction port 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 gas from the exhaust port through the exhaust space; generating the EUV light by irradiating the target material with the laser light; An illumination method comprising the above. (Appendix 4) The light source device further includes: a transmission member that transmits the laser light; a laser optical path cover having an open one end and an open other end, the opening diameter of the other end being larger than that of the one end, and having a cylindrical shape in which the diameter increases from the opening of the one end toward the opening of the other end, the one end of the laser optical path cover facing the target material and the other end of the laser optical path cover facing the transmission member; and further includes the above; In the step of exhausting from the exhaust port, Introduce the purge gas from the inlet formed in the laser optical path cover, eject the introduced purge gas from one end of the laser optical path cover toward the target material, and exhaust it from the exhaust port through the exhaust space. The illumination method according to Supplementary Note 3. (Supplementary Note 5) A target material that generates EUV light together with plasma by irradiating laser light, A collector mirror that reflects the generated EUV light, Preparing a light source including: Placing 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. A cylindrical optical path cover having an open one end and an open other end, with the opening diameter of the other end being larger than that of the one end, and the diameter increasing from the opening of the one end toward the opening of the other end. The one end of the optical path cover faces the target material on the target material side of the outer cover, and the other end penetrates the outer cover and faces the collector mirror on the collector mirror side of the outer cover. Closing the other end of the optical path cover with a filter that transmits the EUV light. Forming an inlet through which the purge gas is introduced into the optical path cover. A method for manufacturing a light source device including: (Supplementary Note 6) A cylindrical laser optical path cover having an open one end and an open other end, with the opening diameter of the other end being larger than that of the one end, and the diameter increasing from the opening of the one end toward the opening of the other end. The one end of the laser optical path cover faces the target material, and the other end of the laser optical path cover is arranged so as to allow the laser light to pass through. Closing the other end of the laser optical path cover with the transmission member through which the laser light passes. Forming an inlet through which the purge gas is introduced into the laser optical path cover. comprising A method for manufacturing a light source device according to Supplementary Note 5.

[0104] This application claims priority based on Japanese Patent Application No. 2023-070595 filed on April 24, 2023, and incorporates the entire disclosure thereof herein.

Explanation of Reference Numerals

[0105] 1, 2, 3, 4 Light source device 10 Drum 11, 11a Target material 12 Cooling material 13 Laser light 14 Plasma 15 EUV light 16 Gas 17 Irradiation position 18 Debris 20 Supply case 21 Housing 22 Supply port 23 Supply space 24 Supply unit 25 Wiper 26 Vacuum seal 27 Injection port 28 Window 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 The other end 53 Inlet 60 Filter 70 Transmission member 70a Glass plate 70b Condensing lens 80 Optical path cover 81 One end 82 The other end 83 Inlet 90 Crucible 91 One end 92 The other end 93 Debris shield 101 Light source 240 Exhaust case 241 Outer cover 242 Exhaust port 243 Exhaust space C Central axis

Claims

1. A target material on the surface of a drum that generates EUV light together with plasma by irradiating laser light, 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 communicating with an exhaust space formed on the target material side of the outer cover, a cylindrical optical path cover having an open one end and an open other end, wherein the opening diameter of the other end is larger than that of the one end, and the one end faces the target material and the other end is disposed on the collector mirror side of the outer cover, a filter disposed at the other end of the optical path cover or inside the optical path cover, which transmits the EUV light, a supply case disposed inside the outer cover so as to be covered by the outer cover and having a supply port for supplying gas of the target material to the surface of the drum, comprising, the purge gas introduced from an inlet formed in the optical path cover is jetted from the one end of the optical path cover toward the target material and exhausted from the exhaust port through the exhaust space, a light source device.

2. A target material on the surface of a drum that generates EUV light together with plasma by irradiating laser light, 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 communicating with an exhaust space formed on the target material side of the outer cover, a transmission member that transmits the laser light, a cylindrical laser optical path cover having an open one end and an open other end, wherein the opening diameter of the other end is larger than that of the one end, and the one end of the laser optical path cover faces the target material and the transmission member is disposed at the other end of the laser optical path cover or inside the laser optical path cover, a supply case disposed inside the outer cover so as to be covered by the outer cover and having a supply port for supplying gas of the target material to the surface of the drum, comprising, the purge gas introduced from an inlet formed in the laser optical path cover is jetted from the one end of the laser optical path cover toward the target material and exhausted from the exhaust port through the exhaust space, a 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. The light source device according to claim 1 or 2.

4. A target material on the surface of a drum that generates EUV light together with plasma by irradiating laser light, 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 leading to an exhaust space formed on the target material side of the outer cover, A cylindrical optical path cover having an open one end and an open other end, and having a larger opening diameter at the other end than at the one end, wherein the one end faces the target material and the other end is disposed on the collector mirror side of the outer cover, A filter disposed at the other end of the optical path cover or inside the optical path cover to transmit the EUV light, A supply case disposed inside the outer cover so as to be covered by the outer cover and having a supply port for supplying gas of the target material to the surface of the drum, Preparing 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 gas from the exhaust port through the exhaust space; Generating the EUV light by irradiating the target material with the laser light; An illumination method comprising:

5. A target material on the surface of a drum that generates EUV light together with plasma by irradiating laser light, 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 leading to an exhaust space formed on the target material side of the outer cover, A transmissive member that transmits the laser light, A cylindrical laser optical path cover having an open one end and an open other end, and having a larger opening diameter at the other end than at the one end, wherein the one end of the laser optical path cover faces the target material and the transmissive member is disposed at the other end of the laser optical path cover or inside the laser optical path cover, A supply case that is disposed inside the outer cover so as to be covered by the outer cover and has a supply port for supplying the gas of the target material to the surface of the drum; Preparing a light source device including; Introducing a purge gas from an introduction port formed in the laser optical path cover, ejecting the introduced purge gas from 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; An illumination method comprising.

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

7. A target material on the surface of a drum that generates EUV light together with plasma by irradiating with laser light; A collector mirror that reflects the generated EUV light; Preparing a light source including; 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; Disposing a supply case that is disposed inside the outer cover so as to be covered by the outer cover and has a supply port for supplying the gas of the target material to the surface of the drum; Disposing a cylindrical optical path cover having an open one end and an open other end, and having a larger opening diameter at the other end than at the one end, such 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 inside the optical path cover; Forming an introduction port through which the purge gas is introduced into the optical path cover; A method for manufacturing a light source device comprising.

8. A target material on the surface of a drum that generates EUV light together with plasma by irradiating with laser light; A collector mirror that reflects the generated EUV light; Preparing a light source including; A step of disposing an exhaust case by arranging 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; A step of disposing a supply case having a supply port that is disposed inside the outer cover so as to be covered by the outer cover and supplies the gas of the target material to the surface of the drum; A step of disposing a cylindrical laser optical path cover having an open one end and an open other end, and having a larger opening diameter at the other end than at the one end, such that the one end of the laser optical path cover faces the target material and the other end of the laser optical path cover is arranged to pass the laser light; A step of disposing a transmission member through which the laser light passes at the other end of the laser optical path cover or inside the laser optical path cover; A step of forming an inlet through which purge gas is introduced into the laser optical path cover; A method for manufacturing a light source device comprising the above.

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

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