Light source device

Abstract

To provide a light source device capable of improving stability of light to be taken out.SOLUTION: A light source device 1 according to the present disclosure includes a target holding unit 10 having a holding surface 17 that transports a target material 12 for generating plasma 11 to a plasma formation position 130, and a driving unit 20 that drives the target holding unit 10 to move the holding surface 17. The holding surface 17 moves relative to a processing surface 117 in a space along the holding surface 17. The processing surface 117 has at least one plasma formation position 130, at least one supply position 140 at which the target material 12 is supplied to the holding surface 17, and at least one observation position 150 at which state information of the target material 12 held on the holding surface 17 is acquired. The plasma formation position 130, the supply position 140, and the observation position 150 are disposed along the processing surface 117, and the processing surface 117 includes the supply position 140 disposed after the plasma formation position 130.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a light source device. [Background technology]

[0002] Patent Document 1 describes a light source device that forms a target material on the surface of a cylindrical member that rotates around a rotation axis, and extracts illumination light by irradiating the formed target material with excitation light.

[0003] Patent document 2 describes a light source device that uses centrifugal force to hold a molten metal target material on the inner wall of a crucible that rotates around a rotation axis, and extracts illumination light by irradiating the held target material with excitation light. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-077007 [Patent Document 2] Japanese Patent Publication No. 2022-168463 Summary of the Invention [Problem to be solved by the invention]

[0005] In a light source device, the relative position between the light-emitting point located near the surface of the target material and the optical member may fluctuate due to vibrations that occur when a target holder such as a cylindrical member or crucible rotates, deformation of the structure itself, deformation of the target holder itself due to rotational stress and heat, and the introduction of target material into the target holder, etc. This may result in a case where light cannot be stably extracted from the light source device.

[0006] The object of the present disclosure is to solve such problems and to provide a light source device that can improve the stability of extracted light. [Means for solving the problem]

[0007] The light source device according to the present disclosure comprises a target holding unit having a holding surface that transports a target material for generating plasma to a plasma formation position, and a drive unit that drives the target holding unit to move the holding surface, wherein the holding surface moves relative to a processing surface in a space along the holding surface, the processing surface including at least one of the plasma formation positions, at least one supply position where the target material is supplied to the holding surface, and at least one observation position where status information of the holding surface is acquired, the plasma formation positions, the supply positions, and the observation positions being arranged along the processing surface, and when viewed in the direction of movement of the holding surface by the drive unit, the processing surface includes the supply position that is arranged behind the plasma formation position, and also includes the observation position that is arranged behind the supply position.

[0008] The light source device according to the present disclosure comprises a target holding unit having a holding surface that transports a target material for generating plasma to a plasma formation position, and a drive unit that drives the target holding unit to move the holding surface, wherein the holding surface moves relative to a processing surface in a space along the holding surface, the processing surface including at least one plasma formation position and at least one supply position where the target material is supplied to the holding surface, the plasma formation position and the supply position are arranged along the processing surface, and when viewed in the direction of movement of the holding surface by the drive unit, the length along the processing surface from the plasma formation position to the supply position is shorter than the length along the processing surface from the supply position to the plasma formation position.

[0009] The light source device may further include a plasma generation unit that excites the target material by focusing laser light on the target material at the plasma generation position.

[0010] In the light source device, the target holder may have a rotation axis, and the drive unit may rotate the target holder around the rotation axis to cause the target holder to transport the target material.

[0011] In the light source device, the rotation axis may be substantially perpendicular to the ground surface.

[0012] In the light source device, the processing surface may further have at least one observation position where state information of the holding surface is acquired, and the plasma formation position, the supply position and the observation position may be arranged along the processing surface.

[0013] In the above light source device, when viewed in the direction of movement of the holding surface by the drive unit, the length along the processing surface from the supply position to the observation position may be shorter than the length along the processing surface from the observation position to the plasma formation position.

[0014] The light source device may further include a first debris shield disposed opposite to a region between the plasma generation position and the supply position.

[0015] The light source device may further include a second debris shield disposed opposite to the region between the supply position and the observation position.

[0016] The light source device may further include a third debris shield disposed opposite to the region between the plasma generation position and the observation position.

[0017] The light source device may further include a first debris shield, a second debris shield, and a third debris shield arranged opposite each other in a first region between the plasma generation position and the supply position, a second region between the supply position and the observation position, and a third region between the plasma generation position and the observation position.

[0018] The light source device may further include a plurality of first debris shields, a plurality of second debris shields, and a plurality of third debris shields arranged opposite each other in a first region between the plasma generation position and the supply position, a second region between the supply position and the observation position, and a third region between the plasma generation position and the observation position.

[0019] In the light source device, the first debris shield may include an elongated portion whose distance from the processing surface decreases in the movement direction.

[0020] In the light source device, the angle formed between a portion including an end portion of at least one of the first debris shield, the second debris shield, and the third debris shield on the movement direction side and a tangent to the processing surface on an extension line of the end portion may be less than 90°.

[0021] In the above light source device, the portion including the end portion may include an elongated portion whose distance from the processing surface becomes smaller as the movement direction increases, and may have a convex shape toward the processing surface, so that the angle with respect to the tangent to the processing surface on the extension line of the end portion becomes smaller as the portion approaches the end portion.

[0022] In the light source device, the second debris shield may include a portion that is arranged on a line that extends from the rotation axis of the target holder to the processing surface.

[0023] In the light source device, at least one of the first debris shield, the second debris shield, and the third debris shield may be attached to a debris cover that covers the target holder.

[0024] In the light source device, at least one of the first debris shield, the second debris shield, and the third debris shield may be adjusted to a temperature equal to or higher than the melting point of the target material.

[0025] In the light source device, the plasma generation position may be disposed at a position opposite to the observation position with respect to the rotation axis of the target holding unit. [Effects of the Invention]

[0026] According to the present disclosure, it is possible to provide a light source device that can improve the stability of extracted light. [Brief explanation of the drawings]

[0027] [Figure 1] 3 is a cross-sectional view illustrating the light source device according to the first embodiment, showing a cross section taken along line II in FIG. 2. FIG. [Figure 2] 2 is a cross-sectional view illustrating the light source device according to the first embodiment, taken along line II-II in FIG. 1. FIG. [Figure 3] 2 is a schematic diagram illustrating an internal space of a target holding unit in the light source device 1 according to the first embodiment. FIG. [Figure 4] 6 is a cross-sectional view illustrating the light source device according to the second embodiment, taken along line IV-IV in FIG. 5. FIG. [Figure 5] 5 is a cross-sectional view illustrating the light source device according to the second embodiment, taken along line VV in FIG. 4. FIG. [Figure 6] 10 is a cross-sectional view illustrating a light source device according to a modified example of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, a specific configuration of this embodiment will be described with reference to the drawings. The following description shows a preferred embodiment of the present disclosure, and the scope of the present disclosure is not limited to the following embodiment. In the following description, parts with the same reference numerals indicate substantially the same content.

[0029] <Embodiment 1> A light source device according to a first embodiment will be described. The light source device of this embodiment generates light such as illumination light and exposure light used in optical devices such as inspection devices and exposure devices. The light source device may be provided integrally with the optical device, or may be disposed near the optical device as a separate entity. When the optical device is an inspection device, the light source device generates illumination light that illuminates an inspection object in the inspection device. When the optical device is an exposure device, the light source device generates exposure light that exposes an exposure object in the exposure device.

[0030] The light source device generates light such as illumination light and exposure light by irradiating excitation light onto a target material held in a target holder. In the following embodiment 1, an example of a light source device will be described in which molten metal held in a target holder including a container such as a crucible is used as the target material. In embodiment 2, a light source device will be described in which a solid held in a target holder such as a cylindrical drum is used as the target material. Note that the light source device is not limited to those that use molten metal held in a container such as a crucible as the target material or those that use a solid held in a target holder such as a cylindrical drum as the target material, but may also be those that use solid metal held in a tape-shaped target holder as the target material or droplet-shaped liquid metal as the target material.

[0031] FIG. 1 is a cross-sectional view illustrating the light source device 1 according to the first embodiment, taken along line II in FIG. 2. FIG. 2 is a cross-sectional view illustrating the light source device 1 according to the first embodiment, taken along line II-II in FIG. 1. FIG. 3 is a schematic diagram illustrating the internal space 10a of the target holding unit 10 in the light source device 1 according to the first embodiment. Some members may be omitted from FIGS. 1 to 3 to avoid cluttering the drawings. For example, debris shields 61 to 63 in the cover unit 60 are omitted from FIG. 1.

[0032] 1 to 3, light source device 1 includes a target holding unit 10 and a drive unit 20. In addition to target holding unit 10 and drive unit 20, light source device 1 may further include a forming unit 30, a supply unit 40, an observation unit 50, a cover unit 60, an output optical system 70, and a control unit 80.

[0033] Here, an XYZ Cartesian coordinate system is introduced for the convenience of explanation of the light source device 1. For example, the rotation axis R of the target holder 10 is set to the Z-axis direction. Note that the XYZ Cartesian coordinate system introduced is for the convenience of explanation and does not limit the orientation of each member.

[0034] The target holder 10 holds a target material 12. The target holder 10 may include a container such as a crucible. The target holder 10 is capable of melting metal inside. The target holder 10 holds the target material 12, such as molten metal, which generates plasma 11 when irradiated with excitation light LR. The excitation light LR is, for example, laser light including IR (Infrared) light.

[0035] As will be described later, the target holder 10 is not limited to a container such as a crucible. For example, the target holder 10 may be a cylindrical drum. In this case, the target holder 10 holds the target material 12 by fixing a substance to be the target material 12, such as xenon (Xe), frozen on the surface of the drum in a solid state, for example.

[0036] The target material 12 is not limited to the molten metal held by the target holder 10, but may be a solid substance, solid metal, liquid droplets, or the like, as long as it generates plasma 11 when irradiated with excitation light LR. The molten metal is, for example, melted tin (Sn) or lithium (Li), but is not limited to tin, lithium, or the like, as long as it generates plasma 11 when irradiated with excitation light LR.

[0037] The target holder 10 has a rotation axis R and rotates around the rotation axis R. The rotation axis R may be substantially perpendicular to the ground surface. This allows centrifugal force to act evenly on the target material 12 held by the target holder 10, making it possible to make the thickness of the target material 12 uniform and stabilizing the light L0 extracted from the light source device 1.

[0038] The target holder 10 has, for example, a cylindrical shape with one opening closed. The closed portion of the target holder 10 is called the bottom portion 13. The cylindrical portion of the target holder 10 is called the cylindrical portion 14. The inner surface of the bottom portion 13 is called the bottom surface 15. The inner surface of the cylindrical portion 14 is called the inner wall surface 16. The target holder 10 has a holding surface 17 that holds the target material 12. For example, the target holder 10 has the inner wall surface 16 as the holding surface 17. In this case, the target holder 10 holds the target material 12 on the inner wall surface 16 by centrifugal force. Note that the target holder 10 may have a surface other than the inner wall surface 16, such as the bottom surface 15, as the holding surface 17, as long as it can hold the target material 12 containing molten metal or the like. Furthermore, the target holder 10 may have a shape other than the above, as long as it can hold the target material 12.

[0039] The inner wall surface 16, which is formed to surround the rotation axis R, may have a groove 18 formed along the inner circumference. The groove 18 is formed, for example, along the intersection line between the inner wall surface 16 and a plane perpendicular to the rotation axis R. The groove 18 is recessed in the inner wall surface 16 in a direction away from the rotation axis R. When the inner wall surface 16 has the groove 18, the target material 12 may be held in the groove 18. Holding the target material 12 in the groove 18 limits the movement of the target material 12 in the Z-axis direction, thereby suppressing disturbance of the liquid surface of the target material 12. Furthermore, the amount of target material 12 can be limited within the groove 18, thereby reducing the amount of target material 12 required. Note that a portion of the target material 12 may be located outside the groove 18.

[0040] Note that inner wall surface 16 formed to surround rotation axis R may include a cylindrical portion whose distance from rotation axis R is constant. In addition, inner wall surface 16 may include an inclined surface whose distance from rotation axis R changes. For example, inner wall surface 16 may be provided with a rounded corner at the connection portion with bottom surface 15. As long as it can hold target material 12, the shape of inner wall surface 16 is not limited to having groove 18, a cylindrical surface, an inclined surface, a rounded corner, or the like.

[0041] The target holder 10 is provided with a heater 19. By heating with the heater 19, a target material 12 such as molten metal can be formed on the target holder 10.

[0042] The driver 20 is connected to the target holder 10 via a power transmission mechanism such as a shaft. The driver 20 drives the target holder 10 by transmitting power to the target holder 10. The driver 20 drives the target holder 10 to move the holding surface 17. For example, the driver 20 may rotate the target holder 10 around the rotation axis R to cause the target holder 10 to transport the target material 12. When the target holder 10 is viewed from the +Z axis direction to the -Z axis direction, the driver 20 rotates the target holder 10 around the rotation axis R in a clockwise direction. Note that the driver 20 may also rotate the target holder 10 around the rotation axis R in a counterclockwise direction.

[0043] Here, the predetermined direction in which the driver 20 rotates the target holder 10 around the rotation axis R is referred to as the movement direction. As an example, the direction in which the hands of a clock rotate around the rotation axis R is referred to as the movement direction. As the target holder 10 rotates in the movement direction, the holding surface 17 of the target holder 10 also rotates around the rotation axis R in the movement direction. As a result, the target material 12 also rotates around the rotation axis R in the movement direction. Therefore, the target holder 10 has the holding surface 17 that transports the target material 12, which generates the plasma 11, to the plasma formation position 130.

[0044] As shown in Fig. 3, the target holding unit 10 has an internal space 10a surrounded by an inner wall surface 16. The internal space 10a includes a plasma generation space 130a, a supply space 140a, and an observation space 150a. A generation unit 30 including excitation light LR is disposed in the plasma generation space 130a. A supply unit 40 that supplies target material 12 to the holding surface 17 is disposed in the supply space 140a. An observation unit 50 that acquires state information of the holding surface 17 is disposed in the observation space 150a.

[0045] The space in which the target holder 10 is arranged is referred to as the movement space 110. The movement space 110 includes the space in which the target holder 10 moves. The movement space 110 has a processing surface 117 along the holding surface 17. The processing surface 117 may overlap with the holding surface 17. The holding surface 17 moves relative to the processing surface 117.

[0046] The processing surface 117 may include a plasma formation position 130, a supply position 140, and an observation position 150. The plasma formation position 130 faces the formation unit 30. The plasma formation position 130 includes an area where the plasma 11 is formed by the formation unit 30. The supply position 140 faces the supply unit 40. The supply position 140 includes an area where the target material 12 is supplied to the holding surface 17 by the supply unit 40. The observation position 150 faces the observation unit 50. The observation position 150 includes an area where the observation unit 50 acquires state information of the holding surface 17.

[0047] The processing surface 117 may include multiple plasma formation locations 130, multiple supply locations 140, and multiple observation locations 150. Thus, the processing surface 117 includes at least one plasma formation location 130, at least one supply location 140, and at least one observation location 150.

[0048] The plasma formation position 130, the supply position 140, and the observation position 150 are arranged along the processing surface 117. For example, the plasma formation position 130, the supply position 140, and the observation position 150 are arranged along the processing surface 117 in the rotational direction around the rotation axis R. When viewed in the direction of movement of the holding surface 17 by the drive unit 20, the processing surface 117 includes the supply position 140, which is arranged behind the plasma formation position 130. Furthermore, the processing surface 117 includes the observation position 150, which is arranged behind the supply position 140. Therefore, when viewed in the direction of movement of the holding surface 17 by the drive unit 20, the holding surface 17 includes the supply position 140, which is arranged between the plasma formation position 130 and the observation position 150.

[0049] For example, in the XY plane viewed from the +Z-axis direction to the -Z-axis direction, the position of the processing surface 117 is defined by the angle it forms with the +Y-axis when the rotation axis R is the origin. In this case, the plasma generation position 130 is located, for example, in a region including 0°. The supply position 140 is located, for example, in a region including 90°. The observation position 150 is located in a region including 180°. Therefore, the processing surface 117 includes the supply position 140, which is positioned at +90° in the movement direction from the plasma generation position 130. The processing surface 117 also includes the observation position 150, which is positioned at +90° in the movement direction from the supply position 140.

[0050] In this way, if the direction of movement of holding surface 17 by drive unit 20 is defined as the direction (0° to 360°) in which the angle between rotation axis R and a predetermined radius (for example, +Y axis) with rotation axis R as the origin increases, processing surface 117 includes supply position 140 arranged at a position where the angle (in the movement direction) increases more than plasma generation position 130. Processing surface 117 also includes observation position 150 arranged at a position where the angle (in the movement direction) increases more than supply position 140.

[0051] By making the processing surface 117 include the supply position 140 located behind the plasma generation position 130, it is possible to stabilize the state of the target material 12 supplied at the supply position 140 before forming plasma at the plasma generation position 130. Furthermore, by making the processing surface 117 include the observation position 150 located behind the supply position 140, it is possible to obtain state information of the holding surface 17 including the target material 12 supplied at the supply position 140.

[0052] From the perspective of the internal space 10a, the plasma generation space 130a, the supply space 140a, and the observation space 150a are arranged along the processing surface 117. When viewed in the direction of movement of the holding surface 17 by the drive unit 20, the internal space 10a includes the supply space 140a, which is arranged behind the plasma generation space 130a. The internal space 10a also includes the observation space 150a, which is arranged behind the supply space 140a.

[0053] Furthermore, when viewed in the direction of movement of the holding surface 17 by the drive unit 20, the length along the processing surface 117 from the plasma generation position 130 to the supply position 140 is shorter than the length along the processing surface 117 from the supply position 140 to the plasma generation position 130. In other words, the length measured along the processing surface 117 from the plasma generation position 130 to the supply position 140 in the clockwise direction is shorter than the length measured along the processing surface 117 from the supply position 140 to the plasma generation position in the clockwise direction. With this configuration, it is possible to stabilize the state of the target material 12 supplied at the supply position 140 before generating plasma at the plasma generation position 130.

[0054] Furthermore, when viewed in the direction of movement of the holding surface 17 by the drive unit 20, the length along the processing surface 117 from the supply position 140 to the observation position 150 is shorter than the length along the processing surface 117 from the observation position 150 to the plasma generation position 130. With this configuration, the state of the holding surface 17 after the supply of the target material 12 can be observed while moving the observation position 150 away from the plasma generation position 130. Therefore, the influence of debris generated at the plasma generation position 130 on the observation unit 50 can be reduced, and accurate information about the state of the holding surface 17, such as the thickness of the target material 12 approaching the plasma generation position 130, can be obtained.

[0055] It is preferable that the plasma generation position 130 is disposed at a position opposite the observation position 150 with respect to the rotation axis R of the target holding unit 10. This makes it possible to further reduce the influence of debris generated at the plasma generation position 130 on the observation unit 50.

[0056] From the perspective of the internal space 10a, when viewed in the direction of movement of the holding surface 17 by the drive unit 20, the length along the processing surface 117 from the plasma generation space 130a to the supply space 140a is shorter than the length along the processing surface 117 from the supply space 140a to the plasma generation space 130a. Also, when viewed in the direction of movement of the holding surface 17 by the drive unit 20, the length along the processing surface 117 from the supply space 140a to the observation space 150a is shorter than the length along the processing surface 117 from the observation space 150a to the plasma generation space 130a. Furthermore, it is preferable that the plasma generation space 130a be positioned opposite the observation space 150a with respect to the rotation axis R of the target holder 10.

[0057] The formation unit 30 includes excitation light LR and the like disposed in a plasma formation space 130a. The formation unit 30 excites the target material 12 by focusing laser light LR on the target material 12 at the plasma formation position 130. In this way, the formation unit 30 generates plasma 11 from the target material 12. When the plasma 11 is generated, EUV light LE is generated from the plasma 11. For example, the EUV light LE is used as light L0 such as illumination light in an optical device such as an inspection device or an exposure device.

[0058] The forming unit 30 may include an optical member 31. The optical member 31 irradiates the target material 12 with excitation light LR. The optical member 31 includes, for example, at least one of a mirror and a condenser lens. Note that the optical member 31 is not limited to a mirror or a condenser lens, and may be a laser device that generates the excitation light LR, as long as it is a member that irradiates the target material 12 with excitation light LR.

[0059] The light source device 1 may include a laser device or the like that generates excitation light LR. Alternatively, the light source device 1 may introduce excitation light LR from a laser device installed separately from the light source device 1 outside the light source device 1 into the light source device 1. The laser device, for example, emits excitation light LR including IR light. The excitation light LR may be irradiated onto the target material 12 by controlling the oscillation and stopping of the control unit 80. For example, the excitation light LR is focused by an optical member 31. As a result, the excitation light LR irradiates the target material 12.

[0060] The optical member 31 irradiates the target material 12 with the excitation light LR at an angle tilted toward the front with respect to the direction of movement of the target holder 10 from an axis perpendicular to the surface of the target material 12. This applies angular velocity in the rotation direction of the target holder 10 to the direction in which the debris scatters, and the debris can be scattered in the reflection direction of the excitation light LR, thereby reducing the amount of debris scattered toward the laser device.

[0061] The supply unit 40 is disposed in the supply space 140a. The supply unit 40 supplies the target material 12 to the holding surface 17 at the supply position 140. The supply unit 40 may supply a solid target material 12 to the holding surface 17. The solid target material 12 may be linear. The linear target material 12 may be wound around a bobbin or the like and held thereon. The supply unit 40 supplies the linear target material 12 from the bobbin into the target holding unit 10.

[0062] The supply unit 40 may also supply the molten target material 12 to the holding surface 17. For example, the supply unit 40 may supply the molten target material 12 to the holding surface 17 using a debris shield 62. The debris shield 62 is arranged near the supply position 140. The debris shield 62 is arranged, for example, opposite the supply position 140. The debris shield 62 is exposed to a temperature equal to or higher than the melting point of the target material 12. In this way, the debris shield 62 may be heated to a temperature equal to or higher than the melting point of the target material 12 by radiant heat from the target holder 10 and the target material 12 inside the target holder 10. The debris shield 62 may also be adjusted to a temperature equal to or higher than the melting point of the target material 12 by a heating element such as a heater.

[0063] The debris shield 61 disposed opposite the plasma generation position 130 and the debris shield 63 disposed opposite the observation position 150 may also be adjusted to have a temperature equal to or higher than the melting point of the target material 12. That is, at least one of the debris shields 61 to 63 may be adjusted to a temperature equal to or higher than the melting point of the target material 12. This allows the target material 12 that has become debris to be reused for plasma generation.

[0064] The supply unit 40 may melt the solid target material 12b by bringing it into contact with the debris shield 62 or the like, and supply it into the target holding unit 10. For example, the target material 12 melted by the debris shield 62 falls to the bottom surface 15, and then reaches the inner wall surface 16 by centrifugal force. This eliminates the need to bring the solid target material 12b into contact with the target material 12 on the holding surface 17, making it possible to suppress a decrease in the temperature of the target material 12 on the holding surface 17. In addition, it is possible to suppress disturbance of the surface state of the target material 12 due to vibration or the like.

[0065] The observation unit 50 is disposed in the observation space 150a. The observation unit 50 acquires status information of the holding surface 17 at the observation position 150. The status information of the holding surface 17 may include the surface unevenness, surface roughness, height, reflectance, etc. of the target material 12 held on the holding surface 17. Alternatively, the status information of the holding surface 17 may include the presence and size of scratches or attachments on the holding surface 17. For example, the observation unit 50 acquires the position of the target material 12 held on the holding surface 17 relative to the holding surface 17. In this case, the observation unit 50 includes a position sensor. The observation unit 50 may include various sensors such as a temperature sensor and a stress sensor in addition to the position sensor. The observation unit 50 measures and acquires the surface position of the target material 12 using the position sensor. The position sensor may include, for example, a displacement meter, a high-speed camera, a low-speed camera, a four-segment photodiode (PD), or a time delay integration (TDI) camera. The position sensor may be one that measures the surface position in one dimension, two dimensions, or three dimensions, or may be a combination of several types.

[0066] The observation unit 50, which includes a position sensor and the like, acquires the displacement of the surface position of the target material 12 based on the acquired surface position of the target material 12. The observation unit 50 may acquire the surface position of the target material 12 based on the thickness from the holding surface 17.

[0067] The observation unit 50 is desirably placed at a position away from the plasma generation position 130. For example, the observation unit 50 is placed at a position facing the plasma generation position 130 with respect to the rotation axis R. This makes it possible to suppress the influence of debris and improve the measurement accuracy of the surface position.

[0068] The cover part 60 includes debris shields 61 to 63 and a debris cover 65. It is to be noted that the cover part 60 does not necessarily have to include all of the debris shields 61 to 63 and the debris cover 65. The cover part 60 may include at least one of the debris shields 61 to 63 and the debris cover 65.

[0069] The debris cover 65 is arranged to cover the target holder 10. For example, the debris cover 65 covers the opening on the +Z-axis direction side of the target holder 10. The debris cover 65 has openings formed therein for extracting the excitation light LR and the EUV light LE. The debris cover 65 prevents debris that is scattered when the plasma 11 is generated from adhering to the collector mirror, etc. As mentioned above, the temperature of the debris cover 65 may be adjusted to be equal to or higher than the melting point of the target material 12.

[0070] The debris shield 61 is disposed in the plasma formation space 130a. The debris shield 61 is disposed so as to cover the plasma formation position 130. The debris shield 61 may include a portion disposed facing a region 135 on the processing surface 117 between the plasma formation position 130 and the supply position 140, or may include a portion disposed facing a region 155 on the processing surface 117 between the plasma formation position 130 and the observation position 150. Specifically, the debris shield 61 includes a portion disposed between the formation unit 30 and the supply unit 40, and a portion disposed between the formation unit 30 and the observation unit 50. In this way, the cover unit 60 further includes a first debris shield (part of the debris shield 61) disposed facing the region 135 between the plasma formation position 130 and the supply position 140.

[0071] The debris shield 61 includes a thin elongated portion 61a whose distance from the processing surface 117 decreases as the debris shield moves in the direction of movement, as viewed from the +Z-axis direction in the -Z-axis direction. For example, the portion of the debris shield 61 on the +X-axis side includes a thin elongated portion 61a whose distance from the processing surface 117 decreases. The angle between the thin elongated portion 61a, including the end 61b on the side of the debris shield 61 facing in the direction of movement, and a tangent to the processing surface 117 on an extension of the end 61b is less than 90°. The thin elongated portion 61a, including the end 61b, has a convex shape toward the processing surface 117, as viewed from the +Z-axis direction in the -Z-axis direction, and therefore the angle with respect to the tangent to the processing surface 117 on an extension of the end 61b decreases as the debris shield 61 moves closer to the end 61b.

[0072] The debris shield 62 is disposed in the supply space 140a. The debris shield 62 is disposed so as to cover the supply position 140. The debris shield 62 is also disposed so as to cover the supply unit 40 from both sides. The debris shield 62 may include a portion disposed facing a region 145 on the processing surface 117 between the supply position 140 and the observation position 150, or may include a portion disposed facing a region 135 on the processing surface 117 between the supply position 140 and the plasma formation position 130. Specifically, the debris shield 62 includes a portion disposed between the supply unit 40 and the observation unit 50, and a portion disposed between the supply unit 40 and the formation unit 30. Thus, the cover unit 60 further includes a second debris shield (part of the debris shield 62) disposed facing the region 145 between the supply position 140 and the observation position 150.

[0073] The debris shield 62 may include a portion that is arranged on a line that extends from the rotation axis R of the target holder 10 to the processing surface 117. In other words, the debris shield 62 may include a radial portion. This allows the debris shield 62 to smoothly supply the target material 12, from which the debris has been melted, to the holding surface 17 by centrifugal force.

[0074] The portion of the debris shield 62 that includes the end 62b on the side facing the direction of movement may be curved. The angle formed by the curved portion of the debris shield 62 that includes the end 62b on the side facing the direction of movement and the tangent to the processing surface 117 on the extension of the end 62b may be less than 90°.

[0075] The debris shield 63 is disposed in the observation space 150a. The debris shield 63 is disposed so as to cover the observation position 150. The debris shield 63 is disposed so as to cover both sides of the observation unit 50. The debris shield 63 may include a portion disposed facing a region 155 on the processing surface 117 between the observation position 150 and the plasma generation position 130, or may include a portion disposed facing a region 145 on the processing surface 117 between the observation position 150 and the supply position 140. Specifically, the debris shield 63 includes a portion disposed between the observation unit 50 and the generation unit 30, and a portion disposed between the observation unit 50 and the supply unit 40. Thus, the cover unit 60 further includes a third debris shield (part of the debris shield 63) disposed facing the region 155 between the plasma generation position 130 and the observation position 150.

[0076] The portion including the end 63b on the movement direction side of the debris shield 63 may be curved. The angle formed by the curved portion including the end 63b on the movement direction side of the debris shield 63 and the tangent to the processing surface 117 on the extension line of the end 63b may be less than 90°.

[0077] The cover part 60 includes a first debris shield, a second debris shield, and a third debris shield that are respectively arranged facing each other in a region 135 between the plasma formation position 130 and the supply position 140 on the processing surface 117, a region 145 between the supply position 140 and the observation position 150 on the processing surface 117, and a region 155 between the plasma formation position 130 and the observation position 150 on the processing surface 117. Here, the first debris shield includes a part of the debris shield 61 or a part of the debris shield 62. The second debris shield includes a part of the debris shield 62 or a part of the debris shield 63. The third debris shield includes a part of the debris shield 63 or a part of the debris shield 61.

[0078] At least one of the first debris shield, the second debris shield and the third debris shield may be attached to the debris cover 65 .

[0079] The cover part 60 may include a plurality of first debris shields, a plurality of second debris shields, and a plurality of third debris shields arranged facing each other in a region 135 on the processing surface 117 between the plasma formation position 130 and the supply position 140, a region 145 on the processing surface 117 between the supply position 140 and the observation position 150, and a region 155 on the processing surface 117 between the plasma formation position 130 and the observation position 150. Here, the plurality of first debris shields include a portion of the debris shield 61 and a portion of the debris shield 62. The plurality of second debris shields include a portion of the debris shield 62 and a portion of the debris shield 63. The plurality of third debris shields include a portion of the debris shield 63 and a portion of the debris shield 61.

[0080] The output optical system 70 extracts the light L0 generated by irradiating the target material 12 with the excitation light LR from the light source device 1. The output optical system 70 includes, for example, an optical member 71. The optical member 71 includes, for example, a collector mirror. Note that the optical member 71 is not limited to a collector mirror as long as it is an optical member that extracts the light L0 generated by irradiating the target material 12 with the excitation light LR, and may be a second collector mirror (not shown) that further reflects the light L0 reflected by the collector mirror.

[0081] The optical member 71 reflects the light L0 generated from the target material 12 by irradiation with the excitation light LR. The optical member 71 reflects, for example, the EUV light LE generated by irradiation with the excitation light LR. That is, the light L0 may include the EUV light LE. The EUV light LE is generated from the plasma 11 generated by irradiating the target material 12 with the excitation light LR. The EUV light LE generated from the plasma 11 generated in the target material 12 is emitted as illumination light to an optical device such as an inspection device. Therefore, the illumination light includes the EUV light LE generated from the plasma 11.

[0082] The control unit 80 may control each component of the light source device 1. The control unit 80 is connected to each component of the light source device 1 in a state in which information can be transmitted via a communication line, including wireless or wired lines. The control unit 80 analyzes, for example, state information of the target material 12 acquired by the observation unit 50. The control unit 80 also analyzes output information including the intensity and irradiation position of the light L0, such as illumination light, output by the output optical system 70.

[0083] The control unit 80 controls the plasma formation state, including the intensity and irradiation position of the excitation light LR in the formation unit 30, based on the state information of the target material 12 and the output information of the light L0, such as illumination light. Also, the control unit 80 controls the supply state, including the temperature and supply amount of the target material 12 in the supply unit 40, based on the state information, output information, etc. Also, the control unit 80 controls the temperature, etc. of the cover unit 60, based on the state information, output information, etc.

[0084] Next, the effects of this embodiment will be described. In the light source device 1 of this embodiment, the plasma generation position 130, the supply position 140, and the observation position 150 are arranged along the processing surface 117. When viewed in the movement direction, the processing surface 117 includes the supply position 140, which is arranged behind the plasma generation position 130, and also includes the observation position 150, which is arranged behind the supply position 140. Therefore, it is possible to stabilize the state of the target material 12 supplied at the supply position 140 before forming plasma at the plasma generation position 130. In addition, it is possible to obtain state information of the holding surface 17, including the target material 12 supplied at the supply position 140. Furthermore, it is possible to reduce the influence of the surface state due to the supply of the target material 12 when generating plasma 11 at the plasma generation position 130. In addition, it is possible to accurately obtain state information, such as the thickness of the target material 12 at the plasma generation position 130.

[0085] Furthermore, in the light source device 1, the length along the processing surface 117 from the plasma generation position 130 to the supply position 140 is shorter than the length along the processing surface 117 from the supply position 140 to the plasma generation position 130. Therefore, the state of the target material 12 supplied at the supply position 140 is stabilized before plasma is formed at the plasma generation position 130. Furthermore, with this configuration, the influence of the supply of the target material 12 on the surface state can be reduced.

[0086] Furthermore, in the light source device 1, the length along the processing surface 117 from the supply position 140 to the observation position 150 is shorter than the length along the processing surface 117 from the observation position 150 to the plasma generation position 130. Therefore, the influence of debris generated at the plasma generation position 130 on the observation unit 50 can be reduced.

[0087] <Embodiment 2> Next, a light source device 2 according to a second embodiment will be described. FIG. 4 is a cross-sectional view illustrating the light source device 2 according to the second embodiment, taken along line IV-IV in FIG. 5. FIG. 5 is a cross-sectional view illustrating the light source device 2 according to the second embodiment, taken along line VV in FIG. 4. As shown in FIGS. 4 and 5, the light source device 2 includes a target holder 210 and a driver 220. Note that the light source device 2 may further include a forming unit 230, a supply unit 240, an observation unit 250, a cover unit 260, an output optical system 270, and a controller 280, in addition to the target holder 210 and the driver 220.

[0088] The target holder 210 holds a target material 212. The target holder 210 includes a cylindrical drum 213. The drum 213 is filled with a coolant 214 such as liquid nitrogen. The target holder 210 holds the target material 212 by fixing a solid, which becomes the target material 212, such as frozen xenon (Xe), to an outer circumferential surface 215 of the drum 213. In this embodiment, the holding surface 217 of the target holder 210 includes the outer circumferential surface 215 of the drum 213.

[0089] The driver 220 drives the target holder 210 to move the holding surface 217. The target holder 210 has a rotation axis R. When the target holder 210 is viewed from the +Z axis direction to the −Z axis direction, the driver 220 rotates the target holder 210 around the rotation axis R in the direction of a clock.

[0090] The formation unit 230 is disposed on the +Y-axis direction side of the target holding unit 210. The formation unit 230 irradiates the target material 212 held on the holding surface 217 on the +Y-axis direction side of the target holding unit 210 with excitation light LR traveling in the -Y-axis direction. Therefore, the plasma formation position 130 includes the portion of the holding surface 217 on the +Y-axis direction side.

[0091] The supply unit 240 is disposed on the +X-axis direction side of the target holding unit 210. The supply unit 240 has a supply port 241. The supply port 241 faces the +X-axis direction side of the target holding unit 210. Therefore, the supply position 140 includes a portion of the holding surface 217 on the +X-axis direction side. The supply port 241 is connected to a supply source 243 of a gas 242 for the target material 212. The supply source 243 supplies the gas 242 for the target material 212 to the supply position 140 via the supply port 241. The gas 242 for the target material 212 supplied from the supply port 241 is solidified on the surface of the drum 213, thereby forming the target material 212.

[0092] The observation unit 250 is disposed on the −Y axis direction side of the target holding unit 210. Therefore, the observation position 150 includes a portion of the holding surface 217 on the −Y axis direction side.

[0093] In this embodiment, a target holder 210 is disposed in the movement space 110. The target holder 210 moves in the movement space 110. The movement space 110 has a processing surface 117 along with a holding surface 217. The processing surface 117 may overlap with the holding surface 217. The holding surface 217 moves relative to the processing surface 117.

[0094] The plasma formation position 130, the supply position 140, and the observation position 150 are arranged along the processing surface 117. When viewed in the direction of movement of the holding surface 217 by the drive unit 220, the processing surface 117 includes the supply position 140, which is arranged behind the plasma formation position 130. The processing surface 117 also includes the observation position 150, which is arranged behind the supply position 140.

[0095] When viewed in the direction of movement of the holding surface 217 by the drive unit 220, the length along the processing surface 117 from the plasma generation position to the supply position 140 is shorter than the length along the processing surface 117 from the supply position 140 to the plasma generation position 130. Furthermore, the length along the processing surface 117 from the supply position 140 to the observation position 150 is shorter than the length along the processing surface 117 from the observation position 150 to the plasma generation position 130.

[0096] The cover part 260 includes debris shields 261 to 263. The debris shield 261 is disposed opposite the region 135 between the plasma generation position 130 and the supply position 140. The debris shield 262 is disposed opposite the region 145 between the supply position 140 and the observation position 150. The debris shield 263 is disposed opposite the region 155 between the plasma generation position 130 and the observation position 150.

[0097] As in this embodiment, even when the target material 212 is a solid or the like held by the target holding unit 210 such as a cylindrical drum, the same effects as those of the first embodiment can be obtained. That is, the state of the target material 212 supplied at the supply position 140 can be stabilized before plasma is formed at the plasma generation position 130. Furthermore, state information of the holding surface 217 including the target material 212 supplied at the supply position 140 can be acquired.

[0098] <Modification> 6 is a cross-sectional view illustrating a light source device 2a according to a modification of the second embodiment. As shown in FIG. 6, in this modification, the position of the forming unit 230 differs from that of the light source device 2 of the second embodiment. That is, the forming unit 230 is disposed on the −X axis direction side of the target holding unit 210. The forming unit 230 irradiates the target material 212 held on the holding surface 217 on the −X axis direction side of the target holding unit 210 with excitation light LR traveling in the +X axis direction. Therefore, the plasma generation position 130 includes a portion of the processing surface 117 on the −X axis direction side.

[0099] Even with this configuration, the plasma generation position 130, the supply position 140, and the observation position 150 are arranged along the processing surface 117. When viewed in the direction of movement of the holding surface 217 by the drive unit 220, the processing surface 117 includes the supply position 140, which is arranged behind the plasma generation position 130. The processing surface 117 also includes the observation position 150, which is arranged behind the supply position 140. Other configurations and effects are included in the descriptions of the first and second embodiments.

[0100] 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. Furthermore, the configurations of Embodiments 1 and 2 and the modifications may be combined as appropriate. [Explanation of symbols]

[0101] 1, 2, 2a light source device 10 Target holder 10a Internal space 11. Plasma 12, 12b Target material 13 Bottom 14 Cylindrical part 15 bottom 16 Inner wall surface 17 Retention surface 18 Groove 19 Heater 20 Drive unit 30 Formation part 31 Optical Components 40 Supply section 50 Observation section 60 Cover 61, 62, 63 Debris Shield 61a Elongated section 61b, 62b, 63b ends 65 Debris Cover 70 Output Optical System 71 Optical Components 80 Control Unit 110 Moving Space 117 Treatment Surface 130 Plasma formation position 130a Plasma formation space 135 areas 140 Supply position 140a supply space 145 areas 150 Observation Position 150a Observation space 155 areas 210 Target holder 212 Target material 213 Drums 214 Coolant 215 Outer surface 217 Retaining surface 220 Drive Unit 230 Formation part 240 Supply section 241 Supply Inlet 242 Gas 243 Supplier 250 Observation Section 260 Cover 261, 262, 263 Debris Shield 270 Output Optical System 280 Control Unit L0 light LE EUV light LR excitation light R rotation axis

Claims

1. a target holder having a holding surface for carrying a target material for generating plasma to a plasma formation position; a drive unit that drives the target holder to move the holding surface; Equipped with the support surface moves relative to the processing surface in a space along the support surface; The treatment surface is at least one said plasma formation location; at least one feed location where the target material is fed to the support surface; at least one observation position at which status information of the holding surface is acquired; Including, the plasma generation position, the supply position, and the observation position are arranged along the processing surface; When viewed in the direction of movement of the holding surface by the drive unit, the processing surface is the supply position is located after the plasma formation position; and the observation position being disposed after the supply position; Light source device.

2. a target holder having a holding surface for carrying a target material for generating plasma to a plasma formation position; a drive unit that drives the target holder to move the holding surface; Equipped with the support surface moves relative to the processing surface in a space along the support surface; The treatment surface is at least one said plasma formation location; at least one feed location where the target material is fed to the support surface; Including, the plasma generation position and the supply position are arranged along the processing surface; When viewed in a direction in which the holding surface is moved by the driving unit, a length along the processing surface from the plasma generation position to the supply position is shorter than a length along the processing surface from the supply position to the plasma generation position. Light source device.

3. The plasma generating unit further includes a generating unit that excites the target material by focusing laser light on the target material at the plasma generating position.

3. The light source device according to claim 1.

4. the target holder has a rotation axis, the driving unit rotates the target holder around the rotation axis to cause the target holder to transport the target material; 3. The light source device according to claim 1.

5. The rotation axis is substantially perpendicular to the ground surface. The light source device according to claim 4 .

6. the processing surface further comprises at least one observation position at which condition information of the holding surface is obtained; the plasma generation position, the supply position, and the observation position are arranged along the processing surface; The light source device according to claim 2 .

7. When viewed in a direction in which the holding surface is moved by the driving unit, a length along the processing surface from the supply position to the observation position is shorter than a length along the processing surface from the observation position to the plasma generation position. The light source device according to claim 1 or 6.

8. further comprising a first debris shield disposed opposite a region between the plasma formation position and the supply position; 3. The light source device according to claim 1.

9. further comprising a second debris shield disposed opposite a region between the supply position and the observation position; The light source device according to claim 1 or 6.

10. further comprising a third debris shield disposed opposite a region between the plasma formation position and the observation position; The light source device according to claim 1 or 6.

11. the device further comprises a first debris shield, a second debris shield, and a third debris shield, which are respectively disposed opposite to each other in a first region between the plasma generation position and the supply position, a second region between the supply position and the observation position, and a third region between the plasma generation position and the observation position; The light source device according to claim 1 or 6.

12. the device further comprises a plurality of first debris shields, a plurality of second debris shields, and a plurality of third debris shields, which are respectively arranged to face each other in a first region between the plasma generation position and the supply position, a second region between the supply position and the observation position, and a third region between the plasma generation position and the observation position; The light source device according to claim 1 or 6.

13. the first debris shield includes an elongated portion whose distance from the processing surface becomes smaller in the movement direction; The light source device according to claim 8 .

14. an angle formed between a portion including an end portion of at least one of the first debris shield, the second debris shield, and the third debris shield on the movement direction side and a tangent to the processing surface on an extension line of the end portion is less than 90°; The light source device according to claim 11.

15. The portion including the end portion is a thin portion whose distance from the processing surface becomes smaller as the movement direction increases, By having a convex shape on the processing surface side, the angle with respect to a tangent line of the processing surface on an extension line of the end portion becomes smaller as the end portion approaches. The light source device according to claim 14.

16. the second debris shield includes a portion disposed on a line extending from a rotation axis of the target holder to the processing surface; The light source device according to claim 9 .

17. At least one of the first debris shield, the second debris shield, and the third debris shield is attached to a debris cover that covers the target holder. The light source device according to claim 11.

18. At least one of the first debris shield, the second debris shield, and the third debris shield is adjusted to a temperature equal to or higher than the melting point of the target material. The light source device according to claim 12.

19. the plasma generation position is disposed at a position opposite to the observation position with respect to the rotation axis of the target holding unit; The light source device according to claim 1 or 6.

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