Light source device

Abstract

To provide a light source device capable of improving the luminous efficiency of plasma generated by an energy beam.SOLUTION: A light source device according to an embodiment of the present invention transforms a liquid raw material into plasma by an energy beam to take out radiation, and comprises a rotor, a raw material supply part, and an electric field application part. The rotor is arranged at an incident position of the energy beam. The raw material supply part supplies the liquid raw material to the rotor. The electric field application part applies an electric field to a plasma generating region which is set to an electric potential different from the liquid raw material supplied to the rotor and where plasma is generated by irradiation of the energy beam.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a light source device that can be used to emit X-rays, extreme ultraviolet light, and the like. [Background technology]

[0002] Traditionally, X-rays have been used for medical, industrial and research purposes. In the medical field, X-rays are used for applications such as chest radiography, dental radiography, and CT (Computer Tomography). In the industrial field, X-rays are used for non-destructive testing to observe the inside of materials such as structures and welds, and for non-destructive tomographic testing. In research fields, X-rays are used for applications such as X-ray diffraction to analyze the crystalline structure of materials, and X-ray spectroscopy (X-ray fluorescence analysis) to analyze the constituent elements of materials.

[0003] X-rays can be generated using an x-ray tube. An X-ray tube has a pair of electrodes (anode and cathode) inside it. When a current is passed through the cathode filament to heat it, and a high voltage is applied between the anode and cathode, negative thermions generated from the filament collide at high speed with a target on the surface of the anode, generating X-rays from the target. There is also known a technique for extracting high-intensity X-rays in an X-ray tube by using a liquid metal jet as the target on the anode side and irradiating this target with an electron beam.

[0004] Extreme ultraviolet light (hereinafter also referred to as "EUV (Extreme Ultra Violet) light") with a wavelength of 13.5 nm, which is in the soft X-ray region with a relatively long wavelength among X-rays, has been used as exposure light in recent years. Here, the substrate of the mask for EUV lithography, on which the fine pattern is formed, is a reflective mirror having a laminated structure in which a multilayer film (e.g., molybdenum and silicon) for reflecting EUV light is provided on a substrate made of low thermal expansion glass. Then, an EUV mask is constructed by patterning a material that absorbs radiation with a wavelength of 13.5 nm on the multilayer film.

[0005] The size of unacceptable defects in EUV masks is significantly smaller than that in conventional ArF masks, making them difficult to detect. Therefore, EUV mask inspection is usually performed using what is called actinic inspection, which uses radiation with a wavelength that matches the working wavelength of lithography. For example, inspection using radiation with a wavelength of 13.5 nm makes it possible to detect defects with a resolution better than 10 nm.

[0006] Generally, EUV light source devices include DPP (Discharge Produced Plasma) light source devices, LDP (Laser Assisted Discharge Produced Plasma) light source devices, and LPP (Laser Produced Plasma) light source devices. DPP-type EUV light source devices apply a high voltage between electrodes to which a discharge gas containing EUV-radiating species (gas-phase plasma raw material) is supplied, generating a high-density, high-temperature plasma through discharge, and utilize the extreme ultraviolet light emitted from this plasma.

[0007] An LDP light source device is an improved version of a DPP light source device, and for example, it supplies a liquid high-temperature plasma raw material (e.g., Sn (tin) or Li (lithium)) containing EUV radiating species to the surface of an electrode (discharge electrode) that generates a discharge, irradiates the raw material with an energy beam (e.g., an electron beam or laser beam) such as a laser beam to vaporize the raw material, and then generates high-temperature plasma by discharge.

[0008] The LPP light source device focuses laser light onto droplets of tin (Sn) or lithium (Li), which are the target material for EUV radiation, and excites the target material to generate plasma.

[0009] In this way, it is possible to use a DPP type (LDP type) or LPP type light source device as an EUV light source device that generates EUV light in the soft X-ray region. On the other hand, in EUV light source devices, DPP type (LDP type) devices ultimately generate plasma by discharge between electrodes, so debris caused by the EUV raw material is likely to be generated. The LPP method targets tiny tin droplets, the EUV raw material, and focuses the excitation laser light onto them, so the light source structure is complex.It is also difficult to stably drop and supply tin droplets, making it difficult to stably generate EUV light.

[0010] Patent Document 1 proposes a method of obtaining X-rays by applying a liquid target material for X-ray generation to a disk-shaped rotating body and irradiating the applied liquid material with an energy beam (laser beam). This method makes it possible to obtain high-intensity X-rays with a relatively simple configuration. When the method described in Patent Document 1 is applied to an EUV light source device, it corresponds to the so-called LPP method, but there is no need to supply the liquid EUV raw material as droplets. This makes it easy to supply the EUV raw material and enables the liquid EUV raw material to be reliably irradiated with a laser beam, making it possible to obtain EUV radiation with a device with a relatively simple configuration. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Patent No. 6658324 Summary of the Invention [Problem to be solved by the invention]

[0012] In an LPP light source device such as that described in Patent Document 1, a liquid raw material is vaporized by an energy beam, and the vaporized raw material is subsequently irradiated with the energy beam to heat and excite the raw material, thereby generating high-temperature plasma. From the generated high-temperature plasma, it is possible to extract radiation such as EUV light and X-rays with shorter wavelengths.

[0013] Light source devices that utilize plasma generated by an energy beam are expected to be used as light sources for, for example, lithography devices and various types of inspection devices, and there is a demand for technology that can improve the luminous efficiency of the plasma and increase the intensity of the radiation.

[0014] In view of the above circumstances, an object of the present invention is to provide a light source device capable of improving the luminous efficiency of plasma generated by an energy beam. [Means for solving the problem]

[0015] In order to achieve the above object, a light source device according to one embodiment of the present invention is a light source device that converts a liquid raw material into plasma using an energy beam to extract radiation, and is equipped with a rotating body, a raw material supply unit, and an electric field application unit. The rotating body is disposed at a position where the energy beam is incident. The raw material supply unit supplies the liquid raw material to the rotor. The electric field applying unit is set to a potential different from that of the liquid raw material supplied to the rotor, and applies an electric field to a plasma generation region where plasma is generated by irradiation with the energy beam.

[0016] In this light source device, a liquid raw material is supplied to a rotor placed at a position where the energy beam is incident. The liquid raw material is converted into plasma by irradiation with the energy beam. An electric field is applied to the plasma generation region where the plasma is generated via an electric field application unit set to a different potential from that of the liquid raw material. This makes it possible to change the state of the plasma and improve the luminous efficiency of the plasma generated by the energy beam.

[0017] The electric field applying unit may be a conductor disposed facing the rotor across the plasma generation region.

[0018] The rotating body may be a disk-shaped member having a front surface and a back surface, and may be disposed so that the energy beam is incident on the front surface. In this case, the electric field application unit may be disposed opposite the front surface of the rotating body.

[0019] The light source device may further include a chamber section having a plasma generation section that houses the rotating body and in which the plasma generation region is formed, a beam intake section that takes in the energy beam into the plasma generation region, and a radiation extraction section that extracts the radiation from the plasma generated in the plasma generation region.

[0020] The electric field applying unit may be a member that constitutes at least one of the plasma generating unit, the beam capturing unit, and the radiation extracting unit.

[0021] The chamber unit may have a protrusion that protrudes toward the plasma generation region, and in this case, the electric field application unit may be the protrusion.

[0022] The chamber unit may include a chamber main body to which the beam intake unit and the radiation extraction unit are connected, and a rotator-accommodating chamber at least a part of which is provided inside the chamber main body and which accommodates the rotator. In this case, the electric field application unit may be the rotator-accommodating chamber.

[0023] The rotor-accommodating chamber may be insulated from the chamber body.

[0024] The radiation may be X-rays or extreme ultraviolet light.

[0025] The radiation may be extreme ultraviolet light. In this case, the electric field applying unit may be set to a high potential relative to the liquid raw material supplied to the rotor.

[0026] The potential of the liquid raw material may be set to a negative potential, and in this case, the potential of the electric field applying unit may be set to ground potential.

[0027] The radiation may be hard X-rays. In this case, the electric field applying unit may be set to a low potential with respect to the liquid raw material supplied to the rotor.

[0028] The potential of the liquid raw material may be set to a positive potential, and in this case, the potential of the electric field applying unit may be set to a ground potential.

[0029] The light source device may further include a radiation measuring unit that measures the state of the radiation from the plasma, and a potential control unit that controls the potential difference between the liquid raw material and the electric field application unit based on the measurement results of the state of the radiation.

[0030] The radiation measuring unit may measure the intensity of the radiation. In this case, the potential control unit may control the potential difference between the liquid raw material and the electric field applying unit based on the measurement result of the radiation intensity so as to increase the intensity of the radiation.

[0031] The energy beam may be a laser beam. [Effects of the Invention]

[0032] According to the present invention, it is possible to improve the luminous efficiency of plasma generated by an energy beam. [Brief explanation of the drawings]

[0033] [Figure 1] 1 is a schematic diagram showing an example of the configuration of a light source device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing a configuration example of a raw material supply mechanism. [Figure 3] FIG. 1 is a schematic diagram showing a simple model for applying an electric field to a plasma generation region. [Figure 4] 1 is a schematic diagram for explaining the behavior of plasma when an electric field is applied to plasma that generates EUV light. FIG. [Figure 5] FIG. 1 is a schematic diagram for explaining the behavior of plasma when an electric field is applied to plasma that generates hard X-rays. [Figure 6] FIG. 6 is a schematic diagram showing an example of the configuration of a light source device according to a second embodiment. [Figure 7] FIG. 1 is a schematic diagram showing a simple model for applying an electric field to a plasma generation region. DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0035] First Embodiment [Basic configuration of light source device] FIG. 1 is a schematic diagram showing an example of the configuration of a light source device according to a first embodiment of the present invention. FIG. 1 is a diagram showing a schematic cross section of the light source device 1 taken horizontally at a position at a predetermined height from the installation surface, as viewed from above. In FIG. 1, in order to make it easier to understand the configuration and operation of the light source device 1, cross sections of parts that do not need to be explained are omitted. In the following explanation, the X direction will be referred to as the left-right direction (the positive side of the X axis is the right side, and the negative side is the left side), the Y direction as the front-to-back direction (the positive side of the Y axis is the front side, and the negative side is the rear side), and the Z direction as the height direction (the positive side of the Z axis is the upward side, and the negative side is the downward side). Of course, the application of the present technology is not limited to the direction in which the light source device 1 is used.

[0036] The light source device 1 is an LPP type light source device that converts plasma raw material 23 into plasma using an energy beam EB to extract radiation R. The light source device 1 is capable of emitting radiation R ranging from hard X-rays with wavelengths of 30 nm or less to soft X-rays (including EUV light). Therefore, the light source device 1 can be used as an X-ray generator or an EUV light source device (EUV radiation generator). Of course, the present technology can also be applied to light source devices that emit radiation in other wavelength bands. Hereinafter, the region where the plasma P is generated by irradiation with the energy beam EB will be referred to as a plasma generation region 21.

[0037] The light source device 1 includes a housing 2, a vacuum chamber 3, an energy beam entrance chamber 4, a radiation exit chamber 5, a raw material supply mechanism 6, and a control unit . The housing 2 is configured so that its outer shape is roughly cubic. The housing 2 has an exit hole 8 formed on the front surface, an entrance hole 9 formed on the right side surface, two through holes 10 and 11 formed on the rear surface, and a through hole 12 formed on the left side surface. The material of the housing 2 is not limited, and for example, a metal housing is used.

[0038] In this embodiment, the emission axis EA of the radiation R is set to pass through the emission hole 8 on the front surface and extend in the Y direction (front-rear direction). The radiation R, such as X-rays or EUV light, is extracted along the emission axis EA and emitted forward from the emission hole 8. In this embodiment, the incidence axis IA of the energy beam EB is set so as to extend obliquely leftward from the incidence hole 9 on the right side surface toward the rear side. 1, a beam source 13 that emits an energy beam EB is installed outside the housing 2. The beam source 13 is installed so that the energy beam EB enters the inside of the housing 2 along an incident axis IA. An electron beam or a laser beam can be used as the energy beam EB. The beam source 13 may be configured in any way that can emit the energy beam EB.

[0039] The light source device 1 is provided with a chamber section C including a plurality of chambers. Specifically, the chamber section C has a vacuum chamber 3, an energy beam incident chamber (hereinafter simply referred to as an incident chamber) 4, and a radiation exit chamber (hereinafter simply referred to as an exit chamber) 5. The vacuum chamber 3, the incident chamber 4, and the exit chamber 5 are spatially connected to one another. That is, the vacuum chamber 3 and the incident chamber 4 are connected to one another. Similarly, the vacuum chamber 3 and the exit chamber 5 are connected to one another.

[0040] The vacuum chamber 3 serves as a "plasma generation section" that generates plasma from the plasma raw material 23 by irradiation with the energy beam EB. Therefore, the vacuum chamber 3 forms the plasma generation region 21 described above. Furthermore, a "beam intake section" that intakes the energy beam into the plasma generation region is realized by the incidence chamber 4. The incidence chamber 4 is formed so as to be located on the incidence axis IA of the energy beam EB. Furthermore, the extraction chamber 5 serves as a "radiation extraction section" that extracts and emits radiation from the plasma generated in the plasma generation region. The extraction chamber 5 is disposed on the emission axis EA of the radiation R.

[0041] In this embodiment, the chamber section C (vacuum chamber 3, entrance chamber 4, and exit chamber 5) is composed of a chamber main body 14, an outer protrusion 15 that protrudes forward from the front surface of the chamber main body 14, and two inner protrusions 16 and 17 that protrude inward from the inner surface of the chamber main body 14. The chamber body 14, the outer protrusion 15, and the two inner protrusions 16 and 17 that constitute the chamber C are made of a metal material.

[0042] The chamber main body 14 is configured so that its outer shape is roughly a rectangular parallelepiped, and is disposed so that its front, rear, left, and right faces face the front, rear, left, and right faces of the housing 2, respectively. The chamber body 14 is also disposed so that the front right corner between the front surface and the right side surface is positioned on the incident axis IA of the energy beam EB.

[0043] 1, an emission hole 18 is formed in the front surface of the chamber body 14. The emission hole 18 is formed at a position aligned with the emission hole 8 in the front surface of the housing 2 on the emission axis EA of the radiation R. An outer protrusion 15 is configured to protrude forward from the periphery of the emission hole 18 of the chamber body 14. The outer protrusion 15 is configured to protrude farther forward than the emission hole 8 of the housing 2 so as to be inscribed within the emission hole 8 of the housing 2. Furthermore, an inner protrusion 16 is formed on the inner side of the chamber body 14 so as to protrude inward from the periphery of the emission hole 18 . The space surrounded by the outer protrusion 15 and the inner protrusion 16 functions as the emission chamber 5. The outer protrusion 15 and the inner protrusion 16, which are members that constitute the emission chamber 5, can also be called the emission chamber. The outer protrusion 15 and the inner protrusion 16 may be formed integrally with the chamber body 14 or may be formed separately and then connected to the chamber body 14 .

[0044] The exit chamber 5 is configured to have a cone shape with the exit axis EA of the radiation R as its central axis. The exit chamber 5 is configured so that the cross-sectional area is large in the center in the direction of the exit axis EA of the radiation R and becomes smaller as it approaches the front and rear ends. In other words, the exit chamber 5 has a shape that narrows as it approaches the front and rear ends.

[0045] An entrance window 19 is formed in the front right corner of the chamber body 14. The entrance window 19 is formed at a position aligned with the entrance hole 9 on the right side surface of the housing 2 on the entrance axis IA of the energy beam EB. Furthermore, an inner protrusion 17 is configured on the inner side of the right front corner of the chamber body 14 so as to protrude from a position surrounding the entrance window 19 along the direction of the entrance axis IA of the energy beam EB. Of the internal space of chamber main body 14, the space surrounded by inner protrusion 17 functions as incident chamber 4. Inner protrusion 17 and the front right corner of chamber main body 14, which constitute incident chamber 4, can also be called the incident chamber itself. The inner protrusion 17 may be integrally formed with the chamber body 14 or may be formed separately and then connected to the chamber body 14 .

[0046] The incident chamber 4 is configured to have a cone shape with the incident axis IA of the energy beam EB as its central axis. The incident chamber 4 is configured so that its cross-sectional area decreases as it approaches the end on the inner side of the chamber body 14 in the direction of the incident axis IA of the energy beam EB. In other words, the incident chamber 4 has a shape that narrows as it approaches the end on the inner side.

[0047] Of the internal space of the chamber body 14, the space excluding the internal space of the inner protrusion 16 which functions as the emission chamber 5 and the internal space of the inner protrusion 17 which functions as the incidence chamber 4 functions as the vacuum chamber 3. The part that constitutes the vacuum chamber 3 itself can also be called the vacuum chamber. As shown in FIG. 1, the chamber body 14 has a portion that protrudes from the housing 2 to the outside through a through-hole 12 on the left side of the housing 2, and its tip is connected to an exhaust pump 20. The vacuum chamber 3 is evacuated by the exhaust pump 20, reducing the pressure in the vacuum chamber 3. This suppresses the attenuation of the radiation R generated in the vacuum chamber 3. The inside of the vacuum chamber 3 does not necessarily have to be a vacuum atmosphere as long as it is a reduced pressure atmosphere relative to the entrance chamber 4 and the exit chamber 5. Also, an inert gas may be supplied into the vacuum chamber 3. The specific configuration of the exhaust pump 20 is not limited, and any pump such as a vacuum pump may be used.

[0048] The raw material supply mechanism 6 is a mechanism for generating plasma P in the plasma generation region 21 in the vacuum chamber 3 and emitting radiation R (X-rays, EUV light). The raw material supply mechanism 6 includes a disk-shaped rotor 22 for supplying raw material, and a container 24 that contains a liquid-phase plasma raw material (radiation raw material) 23. The rotor 22 and the container 24 are disposed inside the vacuum chamber 3. 1, an incident area 25 onto which the energy beam EB is incident is set on a disk-shaped rotor 22. The rotor 22 is disposed in the vacuum chamber 3 so that the incident area 25 is located at the intersection of the incident axis IA and the exit axis EA. Plasma raw material 23 is supplied to an incident region 25 of the rotor 22, and an energy beam EB is incident on the incident region 25, thereby generating plasma P. The region (space) in the vacuum chamber 3 where the plasma P is generated is the plasma generation region 21. Therefore, the plasma generation region 21 is a region corresponding to the position of the incidence region 25 of the rotor 22.

[0049] The light source device 1 is provided with an electric field application unit 50 that applies an electric field to the plasma generation region 21 where the plasma P is generated by irradiation with the energy beam EB. The electric field application unit 50 is a member that is set to a different potential from that of the plasma raw material 23 supplied to the rotor 22. Therefore, the potential of the electric field application unit 50 is set to be higher (or lower) than that of the plasma raw material 23.

[0050] Typically, the electric field application unit 50 is a conductor arranged facing the rotor 22 across the plasma generation region 21. In particular, since the electric field application unit 50 is the part exposed to the high-temperature plasma P, it is preferable that it be made of a high-melting-point metal or the like. By appropriately setting the potential of the electric field application unit 50, an electric field is generated in the space between the plasma raw material 23 and the electric field application unit 50 according to the potential difference (voltage) between the plasma raw material 23 and the electric field application unit 50. This electric field is applied to the plasma generation region 21.

[0051] In this embodiment, the electric field application unit 50 is a member that constitutes the chamber unit C. Specifically, a member that constitutes at least one of the vacuum chamber 3, the entrance chamber 4, and the exit chamber 5 is used as the electric field application unit 50. In the example shown in FIG. 1, the chamber body 14 constituting the vacuum chamber 3, the inner protrusion 16 constituting the emission chamber 5, and the inner protrusion 17 constituting the entrance chamber 4 are electrically connected, and the chamber body 14, the inner protrusion 16, and the inner protrusion 17 form the electric field application unit 50. The potential set in the electric field applying unit 50 and the behavior of the plasma P to which the electric field is applied will be described in detail later.

[0052] The control unit 7 controls the operation of each of the components of the light source device 1. For example, the control unit 7 controls the operation of the beam source 13 and the exhaust pump 20. The control unit 7 also controls the operation of various motors, a plasma raw material circulation device, an external voltage source, and the like, which will be described later. The control unit 7 has hardware circuits necessary for a computer, such as a CPU, memory (RAM, ROM), etc. The CPU loads a control program stored in the memory into the RAM and executes it, thereby performing various processes. The control unit 7 may be implemented by a programmable logic device (PLD) such as a field programmable gate array (FPGA), or other devices such as an application specific integrated circuit (ASIC). In FIG. 1, the control unit 7 is illustrated as a schematic functional block, but the position where the control unit 7 is configured may be designed arbitrarily.

[0053] In this embodiment, the control unit 7 controls the potential difference between the plasma raw material 23 and the electric field applying unit 50 based on the measurement results of the state of the radiation R from the radiological diagnostic unit 29, which will be described later. In the example shown in FIG. 1, the light source device 1 is connected to an external voltage source 51. The external voltage source 51 is connected to the plasma raw material 23 (container 24) and applies a given voltage to the plasma raw material 23. The control unit 7 adjusts the output of the external voltage source 51 according to the state of the radiation R, and controls the potential difference between the plasma raw material 23 and the electric field application unit 50. Hereinafter, the potential difference between the plasma raw material 23 and the electric field application unit 50 will be referred to as the applied voltage V to the plasma generation region 21. In this embodiment, the control unit 7 functions as a potential control unit.

[0054] The various chambers that make up the light source device 1 and the raw material supply mechanism 6 will be described in detail below.

[0055] [Incidence chamber] The incident chamber 4 is defined by an inner protrusion 17 at the front right corner of the chamber body 14. An incident window 19 is disposed at the front right corner of the chamber body 14, and the energy beam EB emitted from the beam source 13 passes through the incident window 19 and enters the interior of the incident chamber 4 along the incident axis IA. The incidence axis IA of the energy beam EB can also be said to be the optical axis (principal axis) of the energy beam EB incident on the interior of the incidence chamber 4.

[0056] The entrance window 19 is made of a material that is transmissive to the energy beam EB, and is designed to have a thickness that can withstand the pressure difference between the inside and outside of the entrance chamber 4 . When the energy beam EB is an electron beam, a metal film such as titanium or aluminum can be used. When the energy beam EB is a laser beam, for example, a glass material (quartz glass) can be used. Alternatively, any material that can transmit the energy beam EB may be used.

[0057] The inner protrusion 17 protrudes toward an incident region 25 on the surface 22a of the rotor 22, and an incident-side aperture 26 is formed at the tip of the protruding side. The entrance aperture 26 is arranged to be aligned with the entrance window 19 on the entrance axis IA of the energy beam EB. The entrance-side aperture 26 allows the energy beam EB to enter the vacuum chamber 3 from the entrance chamber 4. That is, the energy beam EB traveling along the entrance axis IA from the entrance window 19 passes through the entrance-side aperture 26 and enters the rotor 22 arranged in the vacuum chamber 3.

[0058] Inside the injection chamber 4, a capture mechanism is arranged to capture the scattered plasma raw material 23 and debris. 1, the capture mechanism is a rotary window 27, which is a plate-shaped rotating member that transmits the energy beam EB and captures the plasma raw material 23 and debris. The rotary window 27 is configured in the shape of, for example, a disk. A rotating shaft of a motor (not shown) is attached to the center of the rotating window 27. The motor rotates the rotating shaft, thereby rotating the rotating window 27. The motor is controlled and driven by the control unit 7. The motor is formed outside the housing 2, and the rotating shaft is connected to the rotary window 27 through a through-hole (not shown) formed in the housing 2 and the chamber main body 14. A mechanical seal is used when the rotating shaft is introduced into the chamber main body 14, and rotation of the rotary window 27 is permitted while maintaining the atmosphere inside the injection chamber 4 (a gas atmosphere described below). In addition, the rotation axis for rotating the rotating window 27 is positioned at a position offset from the incident axis IA of the energy beam EB, which allows the energy beam EB to travel through the beam transmission region of the rotating window 27 without being interfered with by the rotation axis of the rotating window 27. By rotating the rotating window 27, it is possible to increase the effective area of ​​the beam transmission region of the rotating window 27, thereby extending the life of the rotating window 27 and reducing the frequency of replacement of the rotating window 27.

[0059] 1, a gas injection path 28 is installed in chamber body 14 so as to connect to incidence chamber 4. Gas is supplied into incidence chamber 4 via gas injection path 28 from a gas supply device (not shown). The gas to be supplied is a gas that has a high transmittance to the energy beam EB, and for example, a rare gas such as argon (Ar) or helium (He) is used. The gas is supplied to increase the pressure inside incidence chamber 4. That is, by supplying gas into incidence chamber 4 from gas injection path 28, the internal pressure of incidence chamber 4 can be maintained at a pressure that is sufficiently higher than the internal pressure of vacuum chamber 3. Inner protrusion 17 has a cone shape whose cross-sectional area decreases toward the protrusion side (the side where entrance-side aperture 26 is formed). At its tip, entrance-side aperture 26 is provided. This configuration is advantageous for supplying gas to increase the internal pressure of entrance chamber 4. Furthermore, by configuring the inner protrusion 17 in a cone shape, it is possible to reduce the space occupied by the inner protrusion 17 within the chamber body 14, thereby improving the degree of freedom in the layout design of other components, etc. As a result, it is possible to miniaturize the device.

[0060] [Exit chamber] The exit chamber 5 has a cone shape with the exit axis EA as its central axis, and a utilization device such as a mask inspection device is connected to the front end (the front end of the outer protrusion 15). In the example shown in Fig. 1, an application chamber 30 is connected as a chamber that forms part of the utilization device. The pressure inside the application chamber 30 may be atmospheric pressure. If necessary, the inside of the application chamber 30 may be purged by introducing a gas (e.g., an inert gas) through the gas injection path 31. The gas inside the application chamber 30 may be exhausted by an exhaust means (not shown).

[0061] 1, a gas injection path 32 is provided in the outer protrusion 15 so as to connect to the emission chamber 5. Gas is supplied into the emission chamber 5 via the gas injection path 32 from a gas supply device (not shown). The gas to be supplied is a gas that has a high transmittance to the radiation R, and for example, a rare gas such as argon or helium is used. Argon and helium can be used as gases that have high transmittance for both the energy beam EB and the radiation R. Therefore, the same gas may be supplied to both the entrance chamber 4 and the exit chamber 5. In this case, the gas supply device can be shared, which simplifies the device. Of course, different gases may be supplied to the entrance chamber 4 and the exit chamber 5. The gas is supplied to increase the pressure inside the emission chamber 5. That is, by supplying gas into the emission chamber 5 from the gas injection path 32, the internal pressure of the emission chamber 5 can be maintained at a pressure sufficiently higher than the internal pressure of the vacuum chamber 3.

[0062] A collector (condensing mirror) 33 is disposed inside the exit chamber 5 to guide and condense the radiation R that has entered the exit chamber 5 into the utilization device (inside the application chamber 30). In Fig. 1, the components of the radiation R that enter the exit chamber 5 and are condensed are shown by hatching. The outer surface of the collector 33 contacts the inner surface of the exit chamber 5 (the inner surface of the outer protrusion 15) for cooling and alignment purposes. For example, a single-shell grazing incidence reflector is used as the collector 33. The main body of the collector 33 is made of a metal member (for example, aluminum (Al), nickel (Ni), or stainless steel).

[0063] The reflective coating on the inner reflective surface of the collector 33 is optional, but a suitable reflective coating material for reflecting the radiation R is, for example, ruthenium (Ru). Instead of having a structure in which the collector 33 has a body coated with expensive Ru, the body may be made of glass (silicon dioxide: SiO2) and the inside may be polished to form a radiation reflecting surface. Although the reflectivity of the reflective surface of this glass collector is lower than that of a collector made of a metal member with a Ru coating, the material cost is much lower than that of the Ru-coated collector, and frequent replacement is possible.

[0064] The inner protrusion 16 that constitutes the exit chamber 5 protrudes toward the incident region 25 on the surface 22a of the rotor 22, and an exit-side aperture 34 is formed at the tip of the protruding side. The exit aperture 34 is arranged on the exit axis EA of the radiation R so as to be aligned with the exit hole 18 of the chamber body 14 and the exit hole 8 of the housing 2. The exit aperture 34 allows the radiation R to enter the exit chamber 5 from the vacuum chamber 3. That is, a portion of the radiation R emitted from the plasma P passes through the exit aperture 34 and enters the collector 33. The radiation R is guided by the collector 33 and collected in the application chamber 30. By appropriately designing the opening area of ​​the exit aperture 34, it is possible to control the divergence angle of the radiation R incident on the collector 33. The emission axis EA of the radiation R can also be said to be the optical axis (main axis) of the radiation R taken into the extraction chamber 5 from the plasma P.

[0065] The inner protrusion 16 has a cone shape whose cross-sectional area decreases toward the protrusion side (the side where the output aperture 34 is formed). Therefore, the inner protrusion 16 can also be called a collector cone. The cone-shaped inner protrusion 16 has an exit aperture 34 at its tip, which is advantageous for supplying gas to increase the internal pressure of the exit chamber 5 . Furthermore, by configuring the inner protrusion 16 in a cone shape, it is possible to reduce the space occupied by the inner protrusion 16 within the chamber body 14, thereby improving the degree of freedom in the layout design of other components, etc. As a result, it is possible to miniaturize the device.

[0066] As shown in FIG. 1, a filter membrane 35 is provided between the emission chamber 5 and the application chamber 30 . The filter film 35 serves to physically separate (physically separate the spaces) the plasma generation region 21 in the vacuum chamber 3 from the application chamber 30, and prevents scattered plasma raw materials 23 and debris from entering the application chamber 30. The filter film 35 is made of a material that transmits the radiation R generated in the plasma generation region 21. When the radiation R is X-rays, the filter film 35 is made of, for example, a beryllium thin film that has a very high transmittance for X-rays. When the radiation R is EUV light, the filter film 35 is made of, for example, zirconium (Zr).

[0067] Although gas is supplied into the emission chamber 5, the atmosphere is reduced pressure because it is spatially connected to the vacuum chamber 3. On the other hand, the pressure inside the application chamber 30 may be atmospheric pressure as described above. In this case, a pressure difference occurs between the emission chamber 5 and the application chamber 30. Therefore, the thickness of the filter film 35 is set to a value that can withstand this pressure difference. In other words, the filter film 35 is configured so as not to destroy the reduced pressure atmosphere in the emission chamber 5, which is spatially connected to the vacuum chamber 3.

[0068] Inside the emission chamber 5, a shielding member (central shielding) 36 is arranged. The shielding member 36 is arranged on the emission axis EA of the radiation R so as to be aligned with the emission hole 18 of the chamber body 14, the emission hole 8 of the housing 2, and the filter film 35. Among the radiation R emitted from the plasma P and entering the exit chamber 5, there may be radiation components that are not collected by the collector 33 and travel within the exit chamber 5. At least a portion of these uncollected radioactive components travels while diverging. Such radiation components are usually not used in the utilization device and are often unnecessary. In this embodiment, the shielding member 36 can block radiation components that are not collected by the collector 33 .

[0069] 1, in this embodiment, a gas nozzle 37 is installed to extend in the left-right direction on the rear side of incidence chamber 4. Gas nozzle 37 is installed on the right side surface of chamber body 14 via a seal member or the like. The gas nozzle 37 is connected to a gas supply device (not shown) and supplies gas into the chamber body 14 . 1, gas is sprayed from the gas nozzle 37 from the right side of the interaxial region between the incident axis IA and the exit axis EA to the left side along the left-right direction, thereby making it possible to move debris emitted from the incident region 25 in a direction away from the incident axis IA and the exit axis EA.

[0070] [Raw material supply mechanism] FIG. 2 is a schematic diagram showing an example of the configuration of the raw material supply mechanism 6. As shown in FIG. Fig. 2 shows the rotor 22 and the container 24 as viewed from the direction of arrow A in Fig. 1. Therefore, Fig. 2 shows the surface 22a side of the rotor 22. As shown in FIGS. 1 and 2, the raw material supply mechanism 6 includes a rotor 22, a container 24, a motor 38, a shaft 39, a skimmer 40, and a plasma raw material circulation device 41.

[0071] The rotor 22 is a disk-shaped member that rotates around a rotation axis O to supply plasma raw material 23 to the plasma generation region 21. The rotor 22 has a front surface 22a and a back surface 22b, and is positioned so that the energy beam EB is incident on the front surface 22a. An incident region 25 onto which the energy beam EB is incident is set at a predetermined position on the front surface 22a. Conversely, of the two main surfaces of the rotor 22, the main surface on which the incident region 25 onto which the energy beam EB is incident is set is the front surface 22a, and the opposite main surface is the back surface 22b.

[0072] Therefore, the plasma generation region 21 where the plasma P is generated is a region facing the surface 22a of the rotor 22. The electric field application unit 50 that applies an electric field to the plasma generation region 21 is arranged facing the surface 22a of the rotor 22. Here, "arranged facing the surface 22a" means, for example, being arranged at a position facing the surface 22a (a position visible from the surface 22a). 1, the inner wall on the front side of the chamber body 14, which serves as the electric field application unit 50, and the inner protrusion 17 are arranged opposite the surface 22a. By using a member facing the surface 22a as the electric field application unit 50 in this manner, it becomes possible to efficiently apply an electric field to the plasma generation region 21.

[0073] In order to apply an electric field to the plasma generation region 21, the parts of the raw material supply mechanism 6 that come into contact with the plasma raw material 23 (rotating body 22, container 24, skimmer 40, plasma raw material circulation device 41) and the parts electrically connected to them (motor 38 and shaft 39) are insulated from the parts that become the electric field application unit 50 (chamber body 14, and inward protrusions 16 and 17 in FIG. 1). Therefore, the container 24 is placed on the chamber body 14 via an insulating base or the like, and the parts connected to the container 24 and the rotating body 22 are also configured appropriately so as not to short-circuit with the chamber body 14 or the like.

[0074] The rotor 22 is made of a high melting point metal such as tungsten (W), molybdenum (Mo), or tantalum (Ta). A portion of the lower side of the rotor 22 is immersed in the plasma raw material 23 stored in the container 24. At this time, the position of the rotor 22 and the amount of plasma raw material 23 stored in the container 24 are set so that at least a portion of the surface 22a of the rotor 22 is immersed in the plasma raw material 23.

[0075] When X-rays are emitted as the radiation R, an X-ray raw material is used as the plasma raw material 23. The X-ray raw material is a metal that is liquid at room temperature, and for example, gallium (Ga) or a gallium alloy such as Galinstan (registered trademark), which is a eutectic alloy of gallium, indium (In) and tin (Sn), can be used. When EUV light is emitted as the radiation R, an EUV raw material is used as the plasma raw material 23. As the raw material for emitting EUV light, for example, liquid tin (Sn) or lithium (Li) is used. Since Sn and Li are solid at room temperature, a temperature control means (not shown) is provided in the container 24. For example, when the EUV raw material is Sn, the container 24 is maintained at a temperature equal to or higher than the melting point of Sn.

[0076] A shaft 39 of a motor 38 is connected to the center of the rear surface 22b of the rotor 22. The operation of the motor 38 is controlled by the control unit 7, and the rotor 22 is rotated via the shaft 39. The shaft portion 39 is a columnar member extending in a direction perpendicular to the surface 22a of the rotor 22, and its central axis serves as the rotation axis O of the rotor 22 and the motor . The shaft 39 passes through the through-hole 10 of the housing 2 and is introduced into the vacuum chamber 3 via the mechanical seal 42. At this time, the shaft 39 is positioned so as not to come into contact with the housing 2 (through-hole 10). The mechanical seal 42 allows the shaft 39 to rotate while maintaining the reduced pressure atmosphere inside the vacuum chamber 3. The mechanical seal 42 is also made of an electrically insulating material, and insulates the shaft 39 (rotating body 22) from the vacuum chamber 3.

[0077] As described above, the rotor 22 is positioned so that it is immersed in the plasma raw material 23 stored in the container 24. In this state, when the rotor 22 rotates around the shaft 39, the plasma raw material 23 that has adhered to the surface 22a is pulled up from the container 24. In this manner, the plasma raw material 23 is applied to the entire circumference of the surface 22a. Furthermore, as the rotor 22 rotates, the plasma raw material 23 that has been applied to the surface 22a is transported to the incidence region 25 of the energy beam EB. In this manner, in this embodiment, the plasma raw material 23 is supplied to the rotor 22 by the container 24, motor 38, and shaft 39. In this embodiment, the container 24, motor 38, and shaft 39 constitute a raw material supply unit.

[0078] 2, in this embodiment, an incident region 25 onto which the energy beam EB is incident is set near the periphery of the surface 22a of the rotor 22. The configuration and operation of the raw material supply unit (motor 38 and shaft unit 39) are appropriately designed so that the plasma raw material 23 is supplied to this incident region 25.

[0079] Skimmer 40 is provided at a predetermined position on the periphery of rotor 22 as a film thickness adjusting member for adjusting the film thickness of plasma raw material 23 supplied onto surface 22a of rotor 22 to a predetermined film thickness. The skimmer 40 is, for example, a structure having a channel structure, and is arranged with a predetermined gap therebetween so as to sandwich the rotor 22. The skimmer 40 functions as a scraper that scrapes off part of the plasma raw material 23 applied to the surface 22a of the rotor 22.

[0080] The distance between surface 22a of rotor 22 and skimmer 40 corresponds to the film thickness of plasma raw material 23 in incident region 25, where energy beam EB is incident, on surface 22a of rotor 22. Skimmer 40 is positioned so that the film thickness of plasma raw material 23 in incident region 25 on surface 22a of rotor 22 can be adjusted to a predetermined film thickness. The distance between surface 22a of rotor 22 and skimmer 40 is set appropriately. As a result, when liquid plasma raw material 23 applied to rotor 22 in the raw material storage portion of container 24 passes through skimmer 40 due to the rotation of rotor 22, the film thickness on rotor 22 is adjusted to a predetermined thickness.

[0081] The plasma raw material 23 on the rotor 22, whose film thickness has been adjusted by the skimmer 40, is transported to the incident region 25 where the energy beam EB is incident as the rotor 22 rotates. That is, the rotation direction of the rotor 22 is the direction in which the plasma raw material 23 on the rotor 22 is transported to the incident region 25 after passing through the skimmer 40. Then, in the incident region 25, the energy beam EB is irradiated onto the plasma raw material 23 on the rotor 22, and plasma P is generated. Skimmer 40 makes it possible to supply plasma raw material 23 almost uniformly to incident region 25. By stabilizing the thickness of plasma raw material 23 in incident region 25, it becomes possible to stabilize the intensity of radiation R emitted from plasma P.

[0082] The plasma raw material circulation device 41 replenishes the container 24 with plasma raw material 23 as needed when the plasma raw material 23 is consumed in the operation of generating radiation R. The plasma raw material circulation device 41 also functions as a temperature adjustment mechanism (cooling mechanism) for the plasma raw material 23.

[0083] As shown in FIG. 2, plasma raw material circulation device 41 includes raw material inlet pipeline 44, raw material outlet pipeline 45, raw material storage tank 46, raw material drive unit (pump) 47, and temperature adjustment mechanism 48. The raw material storage tank 46 stores the plasma raw material 23 . The raw material inlet pipe 44 and the raw material outlet pipe 45 are installed between the raw material storage tank 46 and the container 24 so as to communicate between the raw material storage tank 46 and the container 24 . Raw material driver 47 is installed in raw material inlet pipeline 44. When raw material driver 47 is driven, plasma raw material 23 stored in raw material storage tank 46 flows out into raw material inlet pipeline 44, making it possible to circulate plasma raw material 23 through a circulation system consisting of raw material storage tank 46, raw material inlet pipeline 44, container 24, and raw material outlet pipeline 45. For example, an electromagnetic pump capable of transporting liquid metal (plasma raw material 23) by magnetic force is used as raw material driver 47. Of course, other types of pumps may also be used.

[0084] In this embodiment, the raw material storage tank 46 and the raw material driving unit 47 are disposed outside the vacuum chamber 3 and also outside the housing 2. Raw material inlet pipe 44 and raw material outlet pipe 45, which extend from plasma raw material circulation device 41 to container 24, pass through through-hole 11 in housing 2, are introduced into vacuum chamber 3 via seal member 49, and are connected to container 24. At this time, raw material inlet pipe 44 and raw material outlet pipe 45 are positioned so as not to come into contact with housing 2 (through-hole 11). The seal member 49 allows the raw material inlet pipe 44 and the raw material outlet pipe 45 to pass through from the outside to the inside of the vacuum chamber 3 while maintaining the reduced pressure atmosphere inside the vacuum chamber 3. The seal member 49 is made of an electrically insulating material, and insulates the raw material inlet pipe 44 and the raw material outlet pipe 45 (plasma raw material 23) from the vacuum chamber 3.

[0085] Of the plasma raw material 23 applied to the surface 22a of the rotor 22, the portion irradiated with the energy beam EB is consumed. Therefore, in order to stably generate radiation R (X-rays or EUV light) for a long period of time, it is necessary to store a large amount of plasma raw material 23 in the container 24. On the other hand, due to the size of the vacuum chamber 3 of the light source device 1, there are restrictions on the size of the container 24 that can be accommodated inside the vacuum chamber 3, and it is often difficult to store a large amount of plasma raw material 23 in the container 24. Therefore, a raw material storage tank 46 capable of storing a large volume of plasma raw material 23 is installed outside the vacuum chamber 3, and the raw material storage portion of the container 24 can be replenished with plasma raw material 23 via a raw material inlet pipe 44. This allows the amount of plasma raw material 23 in the raw material storage portion of the container 24 to be kept constant for a long period of time, and as a result, the radiation R can be generated stably for a long period of time. That is, plasma raw material circulation device 41 circulates plasma raw material 23 between the raw material storage portion of container 24 and raw material storage tank 46 so that the amount of plasma raw material 23 in the raw material storage portion of container 24 remains constant.

[0086] Furthermore, when the plasma raw material 23 applied to the surface 22a of the rotor 22 is irradiated with the energy beam EB, radiation R is emitted from the plasma raw material 23 (target), and at the same time the rotor 22 itself is heated. This heated rotor 22 exchanges heat with the plasma raw material 23 in the container 24 every time it passes through the raw material storage section of the container 24 in which the plasma raw material 23 is stored. Therefore, if left as is, the temperature of the plasma raw material 23 inside the container 24 will gradually change. If the viscosity of the plasma raw material 23 changes with temperature, the wettability of the plasma raw material 23 with respect to the rotor 22 will change as the temperature of the plasma raw material 23 changes, and the state of adhesion of the plasma raw material 23 to the rotor 22 will change. As a result, the output of the radiation R may also change.

[0087] The plasma raw material circulation device 41 according to this embodiment includes a relatively large raw material storage tank 46 outside the vacuum chamber 3 (outside the housing 2). Therefore, even if plasma raw material 23 whose temperature has changed in the raw material storage portion of container 24 flows into raw material storage tank 46 via raw material discharge pipe 45, the temperature of plasma raw material 23 in raw material storage tank 46 does not change significantly and is kept almost constant. Then, the plasma raw material 23 , which is maintained at a substantially constant temperature, is flowed into the container 24 via the raw material inlet pipe 44 . In this way, by circulating the plasma raw material 23 using the plasma raw material circulation device 41, the temperature of the plasma raw material 23 inside the container 24 is kept almost constant. Therefore, the state of adhesion of the plasma raw material 23 to the rotor 22 is stabilized, and the output of the radiation R can be stabilized.

[0088] Furthermore, the temperature of the plasma raw material 23 in the raw material storage tank 46 may be adjusted by a temperature adjustment mechanism 48 provided inside the raw material storage tank 46 . Because the raw material storage tank 46 is installed outside the vacuum chamber 3 (outside the housing 2), it is possible to use a large-capacity temperature adjustment mechanism 48 that is not affected by the size of the vacuum chamber 3. This makes it possible to reliably adjust the temperature of the plasma raw material 23 to a predetermined temperature in a short period of time.

[0089] In this way, by using plasma raw material circulation device 41 having temperature adjustment mechanism 48, it is possible to supply plasma raw material 23 to the raw material storage portion of container 24 while maintaining the temperature of plasma raw material 23 constant. For example, the temperature in the liquid state is higher than room temperature. expensive Assume that liquid metal is used as the plasma raw material 23. In this case, it is also possible to supply the liquid phase plasma raw material 23 to the container 24 while keeping it at a temperature lower than room temperature. Furthermore, suppose that a liquid metal whose temperature in the liquid state is lower than room temperature is used as plasma raw material 23. Even in this case, it is possible to supply liquid-phase plasma raw material 23 to container 24 while maintaining the temperature higher than room temperature.

[0090] 1, in this embodiment, a radiological diagnostic section 29 is configured on the front side of the chamber body 14 in an area spatially connected to the vacuum chamber 3. The radiological diagnostic section 29 is configured at a position where radiation R, which is emitted in a direction different from the emission axis EA of the radiation R, is incident. The radiological diagnostic unit 29 measures the state of radiation R from the plasma P. Here, the state of radiation R refers to the physical state of radiation R, such as the intensity, wavelength, and spectrum of radiation R. For example, the radiological diagnostic unit 29 is configured by a detector that detects the presence or absence of radiation R and a measuring instrument that measures the output of radiation. The measurement results by the radiation diagnostic unit 29 are used for diagnosing the radiation R and controlling the voltage V applied to the plasma P.

[0091] 1, in this embodiment, an external voltage source 51 is disposed outside the housing 2. The external voltage source 51 can output, for example, a positive high voltage (+HV) or a negative high voltage (-HV) with respect to a GND potential. An output terminal of the external voltage source 51 to which a high voltage is applied is connected to the container 24 via a feedthrough 52 that penetrates the housing 2 and a feedthrough 53 that penetrates the chamber body 14. The feedthroughs 52 and 53 are made of an electrically insulating material. The feedthrough 53 maintains a reduced pressure atmosphere within the vacuum chamber 3. The control unit 7 controls the external voltage source 51, thereby controlling the potential difference (applied voltage V) between the plasma raw material 23 and the electric field applying unit 50.

[0092] [Application of an electric field to the plasma generation region] FIG. 3 is a schematic diagram showing a simple model for applying an electric field to the plasma generation region 21. As shown in FIG. As described above, in this embodiment, the chamber body 14 (vacuum chamber 3) is set as the electric field application unit 50. That is, a component of the vessel (chamber body 14) that forms a vacuum atmosphere (reduced pressure atmosphere) in the plasma generation region 21 is used as the electric field application unit 50. In the example shown in Figure 1, the inner protrusions 16 and 17 provided on the inner wall of the chamber body 14 and protruding toward the plasma generation region 21 are also electrically connected to the chamber body 14 and function as the electric field application unit 50.

[0093] 3 is a schematic diagram of a model in which a rotor 22 to which plasma raw material 23 is supplied and a chamber body 14 serving as an electric field application unit 50 are connected via an insulator 55. In addition, in FIG. 3, the illustration of inner protrusions 16 and 17 is omitted. For example, the insulator 55 may be an insulating base for placing the container 24 in the chamber body 14, an insulating mechanical seal 42 for passing the shaft 39 of the motor 38 through the chamber body 14, and an insulating seal member 49 for passing the raw material inlet pipe 44 and the raw material outlet pipe 45 through the chamber body 14. By providing various insulators 55 between them in this manner, the rotor 22 and the chamber main body 14 are electrically isolated from each other.

[0094] Also, as shown in FIG. 3, in this embodiment, the rotor 22 (plasma raw material 23) is connected to an external voltage source 51 (denoted as HV in FIG. 3), and the chamber body 14 is connected to the GND potential. For example, when the external voltage source 51 outputs a positive high voltage (+HV) with respect to the GND potential, the plasma raw material 23 supplied to the rotor 22 will be at a higher potential than the chamber main body 14. Conversely, when the external voltage source 51 outputs a negative high voltage (-HV) with respect to the GND potential, the plasma raw material 23 supplied to the rotor 22 will be at a lower potential than the chamber main body 14.

[0095] In this case, an electric field corresponding to the potential difference (+HV or -HV) between the plasma raw material 23 and the chamber body 14 is applied to the plasma generation region 21. For example, the greater the voltage applied to the plasma raw material 23, the greater the strength of the electric field applied to the plasma generation region 21. Furthermore, the shorter the distance between the plasma raw material 23 and the chamber body 14, the stronger the electric field strength applied to the plasma generation region 21. For example, by having the inner protrusion 16 (or inner protrusion 17) electrically connected to the chamber body 14 protrude toward the plasma generation region 21, it is possible to increase the strength of the electric field.

[0096] In this way, by applying a high voltage to the plasma raw material 23 side and setting the chamber body 14 at GND potential, it becomes unnecessary to electrically isolate the chamber body 14 from the housing 2, etc. Furthermore, even if an operator directly touches the chamber body 14 or the housing 2, there is no risk of electric shock, making it possible to realize a safe device. The function of the electric field in the plasma generation region 21 will be described below.

[0097] [Electric field action in EUV light sources] FIG. 4 is a schematic diagram for explaining the behavior of plasma when an electric field is applied to plasma that generates EUV light. 4, a case will be described where a plasma P that generates EUV light is generated and an electric field is applied to the plasma P. In this case, EUV raw materials such as Sn and Li are used as the plasma raw material 23. The intensity and wavelength (energy) of the energy beam EB are set appropriately so that EUV light can be generated.

[0098] In the light source device 1, the energy beam EB is irradiated onto the plasma raw material 23, causing the atoms that make up the plasma raw material 23 to separate into negatively charged electrons 60 and positively charged ions 61, generating plasma P. As a result, the plasma P contains a large number of negatively charged electrons 60 and positively charged ions 61. 4, ions 61 that make up the plasma P are shown as large circles, and electrons 60 that make up the plasma P are shown as small circles. Also shown are a rotating body 22 to which plasma raw material 23 is supplied and onto which energy beam EB is incident, and an electric field application unit 50 connected to GND potential, which are shown as rectangular regions.

[0099] When EUV light (extreme ultraviolet light) is generated as radiation R, the electric field application unit 50 is set to a high potential relative to the plasma raw material 23 supplied to the rotor 22. In this case, the plasma raw material 23 is at a low potential, so positively charged ions 61 gather near the plasma raw material 23. This makes it possible to increase the luminous efficiency of the EUV light. The following describes in detail the function of the electric field in the plasma P that generates EUV light. Here, an example is given in which Sn is used as the plasma raw material 23 and laser light is used as the energy beam EB, but other plasma raw materials and energy beams may also be used.

[0100] As shown in Figure 4, liquid tin (Sn) supplied to a rotor 22 is used as a target and is irradiated with a laser beam (laser beam) which is an energy beam EB. The irradiated laser beam vaporizes plasma raw material 23. The vaporized plasma raw material 23 is then irradiated with further laser beam, ionizing the plasma raw material 23 (turning it into plasma). As a result, plasma P is generated which contains positively charged ions 61 (Sn+) and negatively charged electrons 60 (e-). Plasma P is laser-produced plasma generated by irradiating it with laser beam.

[0101] During this process, the volume of the plasma P increases due to adiabatic expansion. The expansion speed of the plasma P is proportional to, for example, the electron temperature Te or the ion temperature Ti. While the volume of the plasma P increases, its density decreases.

[0102] In FIG. 4, the plasma raw material 23, which is the target, is set to a lower potential than the electric field application unit 50, and an electric field is applied to the plasma P (plasma generation region 21). Here, the potential of the electric field applying unit 50 (chamber main body 14, etc.) is set to the GND potential, and the potential of the plasma raw material 23 supplied to the rotor 22 is set to a negative potential. Specifically, a negative high voltage (-HV) is supplied to the container 24 from an external voltage source 51. Then, via the container 24, the potential of the plasma raw material 23 and the rotor 22 becomes -HV.

[0103] In order to generate EUV light, it is important to maintain the plasma P in a high-temperature plasma state capable of emitting EUV light. However, as described above, when the plasma P expands, the temperature of the plasma P decreases, making it difficult to maintain the high-temperature plasma state. As the plasma P expands, the brightness (emission intensity) of the EUV light is likely to decrease.

[0104] 4, with the chamber body 14 set to GND potential, a negative voltage V=-HV is applied to the plasma raw material 23. This generates an electric field in the plasma generation region 21 that moves positively charged ions 61 (Sn+) toward the plasma raw material 23 (rotor 22). The ions 61 (Sn+) that make up the plasma P are attracted toward the rotor 22, and the ion density increases near the rotor 22. In other words, it can be said that the electric field generated in the plasma generation region 21 confines the ions 61 (Sn+). As a result, the expansion of the plasma P is suppressed, maintaining the high-temperature plasma state. This improves the brightness of the EUV light emitted from the plasma P compared to, for example, when no voltage V is applied to the plasma raw material 23.

[0105] Furthermore, the application of an electric field has the effect of confining ions 61 in the plasma P, which makes it possible to suppress the expansion rate of the plasma P, i.e., the cooling rate of the plasma P. This makes it possible to maintain the optimum ion density state for emitting EUV light for a longer period of time than when no electric field is applied. In other words, it is possible to extend the time during which EUV light can be emitted. This makes it possible to improve the luminous efficiency of EUV light (for example, the amount of light emitted per unit time).

[0106] In this way, when the light source device 1 is configured as an EUV light source, it is preferable to set the target plasma raw material 23 to a negative potential, which suppresses the expansion of the plasma P and makes it possible to improve the brightness and luminous efficiency of the EUV light. Such a configuration is useful for increasing the brightness in an inspection light source that uses EUV light, for example.

[0107] [Electric field behavior in hard X-ray sources] FIG. 5 is a schematic diagram for explaining the behavior of plasma when an electric field is applied to plasma that generates hard X-rays. 5, a case will be described where plasma P that generates hard X-rays is generated and an electric field is applied to the plasma P. In this case, X-ray raw materials such as Ga, In, Sn, and gallium alloys are used as plasma raw material 23. The intensity and wavelength (energy) of the energy beam EB are set appropriately so that hard X-rays can be generated.

[0108] When hard X-rays are generated as radiation R, the electric field application unit 50 is set to a low potential relative to the plasma raw material 23 supplied to the rotor 22. In this case, the plasma raw material 23 is at a high potential, so negatively charged electrons 60 gather near the plasma raw material 23. This makes it possible to increase the emission efficiency of hard X-rays. The following describes in detail the function of the electric field in the plasma P that generates hard X-rays. Here, we take as an example a case where Sn is used as the plasma raw material 23 and laser light is used as the energy beam EB, but other plasma raw materials and energy beams may also be used.

[0109] 5, liquid tin (Sn) supplied to a rotor 22 is used as a target and is irradiated with a laser beam (laser beam) that is an energy beam EB, generating plasma P containing positively charged ions 61 (Sn+) and negatively charged electrons 60 (e-). The plasma P is laser-produced plasma generated by irradiation with the laser beam.

[0110] Here, we will explain the process by which hard X-rays are generated. The EUV light mentioned above is generated mainly by the transition of electrons in the outer orbits of the target material. In contrast, hard X-rays are characteristic X-rays with a line spectrum that are generated by exciting electrons in the inner orbits of the target material (inner shell excitation).

[0111] To obtain such characteristic X-rays, it is necessary to excite the inner shell (for example, the K shell) of the atoms in the target material. Inner shell excitation, for example, an electron in the K shell is ejected, creating an empty orbital. When an outer shell electron transitions to this empty orbital, characteristic X-rays are emitted with energy equal to the energy difference between the electron orbitals. The wavelength of the characteristic X-rays depends on the type of target atom.

[0112] Inner shell excitation is caused by electrons in high-temperature plasma. That is, electrons in high-temperature plasma eject inner shell electrons, creating empty orbitals. To generate such electrons in plasma P, it is necessary to irradiate the target material with a high-intensity energy beam EB (laser beam). To enhance this effect, the target material is biased.

[0113] In FIG. 5, the plasma raw material 23, which is the target, is set to a higher potential than the electric field applying unit 50, and an electric field is applied to the plasma P (plasma generation region 21). Here, the potential of the electric field applying unit 50 (chamber main body 14, etc.) is set to the GND potential, and the potential of the plasma raw material 23 supplied to the rotor 22 is set to a positive potential. Specifically, a positive high voltage (+HV) is supplied to the container 24 from an external voltage source 51. Then, via the container 24, the potential of the plasma raw material 23 and the rotor 22 becomes +HV.

[0114] As a result, the electrons 60 (e-) in the plasma P are accelerated toward the rotor 22. Therefore, the electrons 60 (e-) with increased momentum collide with the plasma raw material 23 (Sn) and its ions 61 (Sn+). As a result, inner shell excitation and outer shell electron transitions occur more effectively. In other words, the utilization efficiency of the electrons 60 (e-) increases, and as a result, it is possible to improve the generation efficiency of characteristic X-rays.

[0115] In this way, when the light source device 1 is configured as a hard X-ray light source, it is preferable to set the target plasma raw material 23 at a positive potential. This makes it possible to accelerate electrons 60 in the plasma P, efficiently induce inner-shell excitation, and improve the generation efficiency (brightness) of hard X-rays.

[0116] [Radiation control using electric fields] In this embodiment, the intensity of radiation R (EUV light or hard X-rays) is measured by the radiological diagnostic unit 29 described with reference to Fig. 1. Then, the control unit 7 controls the potential difference between the plasma raw material 23 and the electric field application unit 50 based on the measurement results of the intensity of radiation R so that the intensity of radiation R is increased. That is, the intensity of the radiation R is monitored and the potential difference is set so as to increase the intensity, thereby making it possible to improve the luminous efficiency of the targeted radiation R.

[0117] 1, the applied voltage V (+HV or −HV) output from the external voltage source 51 becomes the potential difference between the plasma raw material 23 and the electric field application unit 50. The control unit 7 controls the magnitude of this applied voltage V, thereby controlling the strength of the electric field applied to the plasma generation region 21. For example, the radiological diagnostic unit 29 detects the spectrum of the radiation R emitted from the plasma P. The control unit 7 monitors the spectrum results and adjusts the applied voltage V so as to increase the intensity of the target wavelength. This makes it possible to sufficiently improve the luminous efficiency of the radiation R.

[0118] Furthermore, it is possible to control the wavelength of the radiation R relatively easily by adjusting the intensity of the electric field while monitoring the wavelength of the radiation R using the radiological diagnosis unit 29. That is, the wavelength of the radiation R may be controlled by controlling the applied voltage V. For example, the spectrum of the radiation R may change depending on the applied voltage V, causing the central wavelength of the radiation R to shift. In this case, it is possible to adjust the applied voltage so that the central wavelength becomes a predetermined wavelength. This makes it possible to stabilize or fine-tune the central wavelength, for example.

[0119] As described above, in the light source device 1 according to this embodiment, the plasma raw material 23 is supplied to the rotor 22, which is placed at a position where the energy beam EB is incident. This plasma raw material 23 is converted into plasma by irradiation with the energy beam EB. An electric field is applied to the plasma generation region 21, where the plasma P is generated, via the electric field application unit 50, which is set to a potential different from that of the plasma raw material 23. This makes it possible to change the state of the plasma P, and improve the luminous efficiency of the plasma P generated by the energy beam EB.

[0120] When the plasma raw material is converted into plasma by the energy beam EB, one method for changing the state of the plasma P is to change the intensity (power) of the energy beam EB. For example, if the energy beam EB is a laser beam, a pulsed laser beam with a high peak power, such as a YAG laser, is used. For example, by irradiating a plasma raw material with a high-intensity pulsed laser beam, a high-temperature plasma with high luminous efficiency is generated, but on the other hand, the laser source that emits the pulsed laser beam may become large.

[0121] In this embodiment, plasma P is generated by irradiating the plasma raw material 23, which serves as a target, with an energy beam EB. To cause this plasma P to emit radiation R (X-rays or EUV light), the potential between the plasma raw material 23 and the electric field application unit 50 (chamber body 14, etc.) is controlled, and an electric field is applied to the plasma generation region 21. This makes it possible to change the state of the plasma P.

[0122] For example, as explained with reference to Figure 4, when generating EUV light, the target (plasma raw material 23) side is set to a negative potential with respect to the chamber body 14, which is connected to GND. This makes it possible to confine positively charged ions 61, suppress the expansion of the plasma P, and maintain a good state of high-temperature plasma. As a result, it becomes possible to improve the luminous efficiency of EUV light in the plasma P.

[0123] Furthermore, as explained with reference to FIG. 5, when generating hard X-rays, the target (plasma raw material 23) side is set to a positive potential with respect to the chamber body 14, which is grounded. This makes it possible to accelerate electrons 60 in the plasma P toward the target. Increasing the number of electrons 60 with high kinetic energy makes it possible to increase the frequency of inner shell excitation that generates hard X-rays. As a result, it becomes possible to improve the emission efficiency of hard X-rays in the plasma P.

[0124] <Second embodiment> A light source device according to a second embodiment of the present invention will be described below. In the following description, the description of the same configurations and functions as those of the light source device 1 described in the above embodiment will be omitted or simplified.

[0125] FIG. 6 is a schematic diagram showing an example of the configuration of a light source device according to the second embodiment. Light source device 101 has a configuration in which a rotator-accommodating chamber 80 is provided in a chamber main body 14. In the following, the same components as those of light source device 1 described with reference to FIG. 1 will be described using the same reference numerals as those in FIG.

[0126] At least a portion of the rotating body accommodating chamber 80 is provided inside the chamber main body 14, and accommodates the rotating body 22. In the example shown in Fig. 6, the rotating body accommodating chamber 80 is configured so that a portion of it protrudes from the chamber main body 14 (vacuum chamber 3). Note that the rotating body accommodating chamber 80 may be completely enclosed inside the chamber main body 14. The rotor accommodating chamber 80 is configured to accommodate the rotor 22, the container 24, a part of the shaft 39, and the skimmer 40 of the raw material supply mechanism 6.

[0127] 6, the rotator-accommodating chamber 80 is a box-shaped container having a parallelogram cross section, and is fitted into an opening 65 provided on the rear surface of the chamber main body 14. The front surface of the rotator-accommodating chamber 80 is disposed along the rotator 22, and parts of the rear surface and left side surface of the rotator-accommodating chamber 80 protrude from the chamber main body 14. These protruding parts function as a partition wall to maintain a reduced pressure atmosphere together with the chamber main body 14.

[0128] The rotator accommodating chamber 80 has an energy beam opening 81 and a radiation opening 82. The energy beam opening 81 is a through-hole provided so that the incident axis IA of the energy beam EB passes through. The radiation opening 82 is a through-hole provided so that the exit axis EA of the radiation R and the exit axis to the radiological diagnosis unit 29 pass through. The plasma generation region 21 of the rotor 22 is irradiated with the energy beam EB through an energy beam opening 81. Radiation R (X-rays or EUV light) emitted from the high-temperature plasma generated by irradiation with the energy beam EB enters the extraction chamber 5 and the radiological diagnosis section 29 through a radiation opening 82. The interior of the chamber body 14 and the interior of the rotor-accommodating chamber 80 are spatially connected via an energy beam opening 81 and a radiation opening 82. Therefore, the interiors of both are maintained in a reduced pressure atmosphere.

[0129] In this embodiment, a rotator-accommodating chamber 80 is used as the electric field applying unit 50. That is, the rotator-accommodating chamber 80 is a member that is set to a different potential from that of the plasma raw material 23 supplied to the rotator 22 in order to apply an electric field to the plasma generation region 21. 6, an output terminal of an external voltage source 51 arranged outside the housing 2 is connected to a rotating body accommodating chamber 80 via a feedthrough 52 that penetrates the housing 2. A positive high voltage (+HV) or a negative high voltage (-HV) is applied to the rotating body accommodating chamber 80 by the external voltage source 51. The operation of external voltage source 51 is controlled by control unit 7.

[0130] On the other hand, the contents contained in the rotor-accommodating chamber 80 (the rotor 22, the container 24, the plasma raw material 23 contained in the container 24, part of the shaft 39, etc.), the chamber body 14, and other components within the chamber body 14 are connected to the GND potential. That is, each part is configured so that a high voltage is applied only to the rotor-accommodating chamber 80 .

[0131] For this reason, in this embodiment, the rotating body accommodating chamber 80 is insulated from the chamber main body 14. Specifically, an insulating member 66 that electrically separates the rotating body accommodating chamber 80 and the chamber main body 14 is provided at the opening 65 of the chamber main body 14. The insulating member 66 is made of an electrically insulating material such as ceramics, and allows the rotor accommodating chamber 80 to penetrate from the outside to the inside of the chamber main body 14 while maintaining the reduced pressure atmosphere in the chamber main body 14 and the rotor accommodating chamber 80.

[0132] The container 24 is placed in the rotor housing chamber 80 via an insulating base or the like. The shaft 39 of the motor 38 is disposed so as to pass through the rotor-accommodating chamber 80. An electrically insulating mechanical seal 42 is used at this passing portion to allow the shaft 39 to rotate while maintaining the reduced pressure atmosphere inside the rotor-accommodating chamber 80. Furthermore, raw material inlet pipe 44 and raw material outlet pipe 45, which connect plasma raw material circulation device 41 to container 24, are arranged so as to pass through rotator-accommodating chamber 80. An electrically insulating seal member 49 is used at this passing-through portion to maintain the reduced pressure atmosphere in rotator-accommodating chamber 80. This electrically insulates the rotor-accommodating chamber 80 from the chamber body 14 , other components within the chamber body 14 , and the contents contained in the rotor-accommodating chamber 80 .

[0133] FIG. 7 is a schematic diagram showing a simple model for applying an electric field to the plasma generation region 21. As shown in FIG. As described above, in this embodiment, the rotator-accommodating chamber 80 provided in the chamber main body 14 is set as the electric field application unit 50. In other words, a member provided separately from the chamber main body 14 is used as the electric field application unit 50.

[0134] 7 is a schematic diagram of a model in which a member that serves as the electric field application unit 50 is introduced into the chamber body 14 via an insulator 55. In this model, the rotor 22 and the chamber body 14 are electrically connected. For example, the insulator 55 may be an insulating base for placing the container 24 in the rotor-accommodating chamber 80, an insulating mechanical seal 42 for passing the shaft 39 of the motor 38 through the rotor-accommodating chamber 80, or an insulating seal member 49 for passing the raw material inlet pipe 44 and the raw material outlet pipe 45 through the chamber body 14. By providing various insulators 55 in this way, the rotor accommodating chamber 80 is electrically isolated from other components.

[0135] As shown in FIG. 7, in this embodiment, the rotor accommodating chamber 80 is connected to an external voltage source 51 (denoted as HV in FIG. 3), and the rotor 22 and the chamber body 14 are connected to the GND potential. For example, when a positive high voltage (+HV) with respect to the GND potential is output from the external voltage source 51, the rotator housing chamber 80 becomes at a higher potential than the plasma raw material 23 supplied to the rotator 22. Conversely, when a negative high voltage (-HV) with respect to the GND potential is output from the external voltage source 51, the rotator housing chamber 80 becomes at a lower potential than the plasma raw material 23 supplied to the rotator 22.

[0136] In this case, an electric field corresponding to the potential difference (+HV or −HV) between the plasma raw material 23 and the rotor-accommodating chamber 80 is applied to the plasma generation region 21 . In this configuration, it is possible to set a relatively short distance between the plasma raw material 23 and the rotator-accommodating chamber 80, which is the electric field application unit 50. Therefore, it is possible to increase the strength of the electric field applied to the plasma generation region 21 compared to a configuration in which the chamber body 14 is used as the electric field application unit 50, as shown in FIG.

[0137] Furthermore, by applying a high voltage to the rotator accommodating chamber 80 and setting the rotator 22 and chamber main body 14 at GND potential, it becomes unnecessary to electrically isolate the rotator 22 and chamber main body 14 from the housing 2, etc. Furthermore, since the motor 38 and plasma raw material circulation device 41 are also at GND potential, the device can be handled safely.

[0138] A case where EUV light is generated in the light source device 101 shown in FIG. 6 will be described. As described above, when generating EUV light, it is desirable to set the target plasma raw material 23 at a lower potential relative to the electric field application unit 50 (see FIG. 4). In this case, a positive applied voltage V (V=+HV) is supplied from an external voltage source 51 to the rotator-accommodating chamber 80, which is the electric field application unit 50. As a result, when plasma P is generated by irradiation with energy beam EB, positively charged ions 61 (e.g., Sn+) contained in plasma P are confined near the rotor 22. This suppresses expansion of plasma P, making it possible to maintain a good high-temperature plasma state. As a result, it becomes possible to improve the luminous efficiency of EUV light in plasma P.

[0139] A case where hard X-rays are generated in the light source device 101 shown in FIG. 6 will be described. As described above, when generating hard X-rays, it is desirable to set the target plasma raw material 23 at a higher potential relative to the electric field application unit 50 (see FIG. 5). In this case, a negative applied voltage V (V=−HV) is supplied from an external voltage source 51 to the rotator-accommodating chamber 80, which is the electric field application unit 50. As a result, when plasma P is generated by irradiating it with energy beam EB, negatively charged electrons 60 contained in plasma P are accelerated toward rotor 22. This increases the number of electrons 60 with high kinetic energy, making it possible to increase the frequency of inner shell excitation that generates hard X-rays. As a result, it becomes possible to improve the emission efficiency of hard X-rays in plasma P.

[0140] In the above, a configuration has been described in which the rotator-accommodating chamber 80 is disposed so as to penetrate the chamber main body 14, as shown in Fig. 6. For example, the rotator-accommodating chamber 80 may be configured so as to fit inside the chamber main body 14. In this case, the rotator-accommodating chamber 80 is provided with through-holes through which the shaft 39, raw material inlet pipe 44, and raw material outlet pipe 45 pass without contacting the rotator-accommodating chamber 80. The chamber main body 14 is also provided with a mechanical seal 42 through which the shaft 39 passes, and a seal member 49 through which the raw material inlet pipe 44 and raw material outlet pipe 45 pass. Note that in this configuration, the mechanical seal 42 and seal member 49 do not need to be electrically insulating.

[0141] Furthermore, instead of the rotator-accommodating chamber 80, a rod-shaped or plate-shaped electrode member may be used as the electric field application unit 50. For example, as shown in the model of Fig. 7, a metal member insulated from members connected to GND potential, such as the chamber body 14, is arranged to face the surface 22a of the rotator 22 across the plasma generation region 21. Even with this configuration, it is possible to apply an electric field to the plasma generation region 21 as needed.

[0142] <Other embodiments> The present invention is not limited to the above-described embodiment, and various other embodiments can be realized.

[0143] In the above, an example has been described in which the chamber body 14 and the inner protruding parts 16 and 17 that are disposed inside the chamber body 14 and protrude into the plasma generation region 21 are electrically connected. For example, the inner protrusion 16 (or the inner protrusion 17) may be insulated from the chamber body 14 and used as the electric field application unit 50. That is, the protrusions (the inner protrusions 16 and 17) protruding toward the plasma generation region may be used as the electric field application unit 50. Such a configuration in which the inner protrusion 16 (or the inner protrusion 17) serves as the electric field application unit 50 can be represented by the model shown in FIG. 7, for example.

[0144] For example, the inner protrusion 16 constituting the radiation R emission chamber 5 is electrically insulated from the chamber body 14 by an insulator (not shown) made of a ceramic material or the like. An output terminal of an external voltage source 51 is connected to the inner protrusion 16. The chamber body 14 and the rotor 22 (plasma raw material 23) are connected to a GND potential. In this case, it is possible to improve the emission efficiency of EUV light by applying a positive voltage (+HV) to the inner protrusion 16. It is also possible to improve the emission efficiency of hard X-rays by applying a negative voltage (-HV) to the inner protrusion 16.

[0145] In addition, by applying a voltage to the inner protrusion 16, the generated electric field can repel ionic debris from the inner protrusion 16 and divert the direction of the debris from the direction of entry into the extraction chamber 5. This effect is also effective when a member other than the inner protrusion 16 is used as the electric field application unit 50. For example, in FIG. 1, the chamber body 14 is connected to the GND potential as the electric field application unit 50. In this configuration, the inner protrusion 16 is insulated from the chamber body 14. A new external voltage source for controlling debris is then provided and connected to the inner protrusion 16. This makes it possible to prevent debris from entering the extraction chamber 5.

[0146] Similarly, the inner protrusion 17 constituting the incident chamber 4 for the energy beam EB may be electrically insulated from the chamber body 14 by an insulator (not shown) made of a ceramic material or the like. In this case, by appropriately applying a high voltage to the inner protrusion 17, it is possible to improve the light emission efficiency of the radiation R.

[0147] In this disclosure, to facilitate understanding of the explanation, words such as "approximately," "almost," and "roughly" are used as appropriate. However, there is no clear difference between using and not using words such as "approximately," "almost," and "roughly." That is, in the present disclosure, concepts that define shape, size, positional relationship, state, etc., such as "center," "central," "uniform," "equal," "same," "orthogonal," "parallel," "symmetrical," "extended," "axial direction," "cylindrical," "cylindrical," "ring-shaped," and "annular," are concepts that include "substantially center," "substantially central," "substantially uniform," "substantially equal," "substantially the same," "substantially orthogonal," "substantially parallel," "substantially symmetrical," "substantially extended," "substantially axial direction," "substantially cylindrical," "substantially cylindrical," "substantially ring-shaped," "substantially annular," and the like. For example, this also includes states that fall within a specified range (for example, a range of ±10%) based on criteria such as "perfectly centered," "perfectly central," "perfectly uniform," "perfectly equal," "perfectly the same," "perfectly perpendicular," "perfectly parallel," "perfectly symmetrical," "perfectly extended," "perfectly axial," "perfectly cylindrical," "perfectly cylindrical," "perfectly ring-shaped," and "perfectly annular." Therefore, even if the words "roughly," "almost," "approximately," etc. are not added, it may include concepts that can be expressed by adding "roughly," "almost," "approximately," etc. Conversely, a state expressed by adding "roughly," "almost," "approximately," etc. does not necessarily exclude a complete state.

[0148] In this disclosure, expressions using "than", such as "greater than A" and "smaller than A", are expressions that comprehensively include both concepts that include equivalent to A and concepts that do not include equivalent to A. For example, "greater than A" is not limited to cases that do not include equivalent to A, but also includes "A or greater." Furthermore, "smaller than A" is not limited to "less than A" but also includes "A or less." When implementing the present technology, specific settings and the like may be appropriately adopted from the concepts included in "greater than A" and "smaller than A" so as to achieve the effects described above.

[0149] It is also possible to combine at least two of the features of the present technology described above. That is, the various features described in each embodiment may be arbitrarily combined without distinction between the embodiments. Furthermore, the various effects described above are merely examples and are not limiting, and other effects may also be achieved. [Explanation of symbols]

[0150] EB...energy beam R...Radiation P...Plasma C: Chamber section 1, 101...Light source device 3...Vacuum chamber 4...Injection chamber 5...Exit chamber 6...Raw material supply mechanism 7...Control unit 13...Beam source 14...Chamber body 16...Inner protrusion 17...Inner protrusion 21...Plasma generation region 22...Rotating body 23...Plasma raw material 50...Electric field application unit 51...External voltage source 80...Rotating body accommodating chamber

Claims

1. A light source device that converts a liquid raw material into plasma using an energy beam to extract radiation, a rotating body disposed at a position where the energy beam is incident; a raw material supply unit that supplies the liquid raw material to the rotor; an electric field applying unit that is set to a potential different from that of the liquid raw material supplied to the rotating body and applies an electric field to a plasma generation region where plasma is generated by irradiation with the energy beam; A light source device comprising:

2. The light source device according to claim 1 , The electric field applying unit is a conductor disposed facing the rotor across the plasma generation region. Light source device.

3. 3. The light source device according to claim 2, the rotating body is a disk-shaped member having a front surface and a back surface, and is disposed so that the energy beam is incident on the front surface; The electric field application unit is disposed opposite the surface of the rotating body. Light source device.

4. The light source device according to any one of claims 1 to 3, further comprising: The apparatus includes a chamber having a plasma generation section that accommodates the rotor and in which the plasma generation region is formed, a beam intake section that intakes the energy beam into the plasma generation region, and a radiation extraction section that extracts the radiation from the plasma generated in the plasma generation region. Light source device.

5. The light source device according to claim 4, The electric field applying unit is a member that constitutes at least one of the plasma generating unit, the beam capturing unit, and the radiation extracting unit. Light source device.

6. The light source device according to claim 4, the chamber portion has a protrusion protruding toward the plasma generation region, The electric field application portion is the protrusion portion. Light source device.

7. The light source device according to claim 4, the chamber unit includes a chamber main body to which the beam intake unit and the radiation extraction unit are connected, and a rotor accommodating chamber at least a portion of which is provided inside the chamber main body and which accommodates the rotor; The electric field applying unit is the rotor housing chamber. Light source device.

8. The light source device according to claim 7, The rotor-accommodating chamber is insulated from the chamber body. Light source device.

9. The light source device according to claim 1 , The radiation is X-rays or extreme ultraviolet light. Light source device.

10. The light source device according to claim 1 , the radiation is extreme ultraviolet light; The electric field applying unit is set to a high potential relative to the liquid raw material supplied to the rotating body. Light source device.

11. The light source device according to claim 10, The potential of the liquid source is set to a negative potential, The potential of the electric field applying unit is set to the ground potential. Light source device.

12. The light source device according to claim 1 , the radiation is hard x-rays, The electric field applying unit is set to a low potential with respect to the liquid raw material supplied to the rotating body. Light source device.

13. The light source device according to claim 12, The potential of the liquid source is set to a positive potential, The potential of the electric field applying unit is set to the ground potential. Light source device.

14. The light source device according to claim 1 , further comprising: a radiation measuring unit that measures the state of the radiation from the plasma; and a potential control unit that controls the potential difference between the liquid raw material and the electric field applying unit based on the measurement result of the state of the radiation. Light source device.

15. 15. The light source device according to claim 14, the radiation measurement unit measures the intensity of the radiation; The potential control unit controls the potential difference between the liquid raw material and the electric field application unit based on the measurement result of the intensity of the radiation so as to increase the intensity of the radiation. Light source device.

16. The light source device according to claim 1 , The energy beam is a laser beam. Light source device.

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