Light source device

Abstract

To provide a light source device capable of achieving long life of a member and improving stability of output of radiation.SOLUTION: A light source apparatus according to an embodiment of the present technology is a light source apparatus that extracts radiation by converting a liquid material into plasma using irradiation with an energy beam, and includes a first member and a beam source. The first member has a first region to which the liquid raw material adheres with a first thickness. The beam source irradiates the first region with the energy beam at a first condensing density, and irradiates the first space, which is a space in which the liquid raw material is diffused by the irradiation at the first condensing density, with the energy beam at a second condensing density. The first condensing density is a condensing density at which the energy beam does not reach the first member when the first region is irradiated with the energy beam.SELECTED DRAWING: FIG. 2B

Description

[Technical Field]

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

[0002] Extreme ultraviolet light (hereinafter referred to as "EUV (Extreme Ultra Violet) light"), a type of X-ray, has recently been used as exposure light. The base material of a mask for EUV lithography is made by patterning a material that absorbs the radiation used for EUV lithography on a multilayer film (e.g., molybdenum and silicon) that reflects EUV light.

[0003] The size of unacceptable defects on EUV masks has become significantly smaller, making them difficult to detect, so EUV masks are inspected using actinic inspection, which uses radiation with a wavelength that matches the working wavelength of lithography.

[0004] 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.

[0005] The DPP light source device applies a high voltage between electrodes to which gaseous plasma raw material (discharge gas) containing EUV radiating species is supplied, generating high-density, high-temperature plasma through discharge, and utilizes the extreme ultraviolet light emitted from it.

[0006] LDP light source devices are an improved version of DPP light source devices, and for example, they supply liquid high-temperature plasma raw material (e.g., Sn (tin) or Li (lithium)) containing EUV-emitting species to the surface of an electrode (discharge electrode) that generates a discharge, irradiate the raw material with a laser beam to vaporize it, and then generate high-temperature plasma through discharge.

[0007] LPP light source devices generate high-temperature plasma by exciting EUV radiating species with a laser beam, etc. A known light source device of this type generates plasma by focusing laser light onto droplets of high-temperature plasma raw material ejected in the form of minute liquid droplets, thereby exciting the target material.

[0008] Patent Document 1 proposes a method of obtaining radiation by supplying a plasma raw material for generating radiation such as X-rays or EUV to a rotor and irradiating the region of the rotor to which the plasma raw material has been supplied with an energy beam (laser beam).A cylindrical container with one open end is used as the rotor, and liquid plasma raw material is supplied to this container, and laser light is irradiated onto the inner peripheral surface of the container.

[0009] This method corresponds to the so-called LPP method, but instead of supplying liquid plasma raw material as droplets, it uses the centrifugal force of a rotor to supply the liquid plasma raw material to the area irradiated by the energy beam. Therefore, compared to methods such as focusing a laser beam on droplets, it is possible to obtain high-intensity radiation with a relatively simple configuration. This becomes: [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-216286 Summary of the Invention [Problem to be solved by the invention]

[0011] In light source devices such as those disclosed in Patent Document 1, there is a demand for technology that can achieve a longer life for components and improve the stability of radiation output.

[0012] In view of the above circumstances, an object of the present invention is to provide a light source device that can achieve a longer life for components and improve the stability of radiation output. [Means for solving the problem]

[0013] In order to achieve the above object, a light source device according to one embodiment of the present technology is a light source device that converts a liquid raw material into plasma by irradiating it with an energy beam to extract radiation, and includes a first member and a beam source. The first member has a first region to which the liquid source is attached with a first film thickness. The beam source irradiates the energy beam at a first light density onto the first region, and irradiates the energy beam at a second light density onto a first space, which is a space into which the liquid raw material has been diffused by irradiation at the first light density. The first light concentration density is a light concentration density at which the energy beam does not reach the first member when the energy beam is irradiated onto the first region.

[0014] In this light source device, an energy beam is irradiated at a first focusing density onto an area where a liquid raw material has adhered to a predetermined film thickness, and then the energy beam is irradiated at a second focusing density into the space where the liquid raw material has diffused. The first focusing density is a focusing density at which the energy beam does not reach the first member when irradiated onto the first area. This suppresses damage to the first member, extends the life of the first member, and improves the stability of the radiation output. Here, the "focusing density at which the energy beam does not reach the first member" refers to a focusing density at which the irradiation of the energy beam does not leave traces such as beam marks or damage on the first member, and this varies depending on the thickness of the film of liquid raw material adhering to the first area.

[0015] The beam source may irradiate a second region, which is different from the first region and on which the liquid raw material is deposited with a second film thickness, with the energy beam at a third focusing density, and irradiate a space that is a common portion between the first space and a second space, which is a space into which the liquid raw material is diffused by irradiation at the third focusing density, with the energy beam at the second focusing density. In this case, the third focusing density may be a focusing density at which the energy beam does not reach the second member when irradiated on the second region.

[0016] The light source device may further include a second member that is different from the first member and has the second region.

[0017] The first member may be a disk-shaped rotating body.

[0018] The first member and the second member may each be a disk-shaped rotating body.

[0019] The first region may be located on a circular surface of the first member, and in this case, the second region may be located on a circular surface of the second member.

[0020] The first region may be located on a side surface of the first member, and in this case, the second region may be located on a side surface of the second member.

[0021] The beam source may emit the energy beam of the first light density and the energy beam of the third light density so as to intersect with each other.

[0022] The beam source may emit the energy beam of the first light density and the energy beam of the third light density so as not to intersect with each other.

[0023] The first member and the second member may both be rotatable about a common shaft member as a rotation axis.

[0024] The beam source may irradiate the energy beam of the first light density and the energy beam of the second light density as pulse waves, and in this case, the energy beam of the first light density and the energy beam of the second light density may be irradiated alternately once.

[0025] The energy beam irradiated at the second focusing density has a pulse width of 10 ns or less and a pulse energy of 0.005 J or more, and when the pulse energy is 0.005 J or more and less than 0.02 J, the intensity of the energy beam is 1 / e of the peak value, where e is the natural logarithm. 2 The spot size, which is the diameter of the part where the laser beam is doubled, may be 100 μm or less, and when the pulse energy is 0.02 J or more and less than 0.05 J, the spot size may be 200 μm or less, when the pulse energy is 0.05 J or more and less than 0.15 J, the spot size may be 300 μm or less, and when the pulse energy is 0.15 J or more, the spot size may be 600 μm or less.

[0026] The energy beam irradiated at the second focusing density may have a pulse width of 10 ns or less, a pulse energy of 0.15 J or more, and a spot size of 600 μm or less, or may have a pulse width of 10 ns or less, a pulse energy of 0.005 J or more, and a spot size of 100 μm or less.

[0027] The light source device may further include an exit chamber disposed on an exit axis of the radiation, in which case the first member may be disposed so that the first region does not face the exit chamber. [Effects of the Invention]

[0028] According to the present invention, it is possible to improve the stability of radiation output. Note that the effects described herein are not necessarily limited to those described herein, and may be any of the effects described in this disclosure. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a schematic diagram illustrating an example of the configuration of a light source device according to an embodiment of the present invention. [Figure 2A] FIG. 2 is a schematic diagram showing a configuration example of a plasma generation mechanism. [Figure 2B] FIG. 2 is a schematic diagram showing a configuration example of a plasma generation mechanism. [Figure 3] 10A to 10C are schematic diagrams showing variations of a rotating body. [Figure 4] 10A to 10C are schematic diagrams showing variations of a rotating body. [Figure 5A] 10A to 10C are schematic diagrams showing variations of a rotating body. [Figure 5B] 10A to 10C are schematic diagrams showing variations of a rotating body. [Figure 6A] 10 is a table showing conditions for the energy beam EB2. [Figure 6B] 10 is a table showing conditions for the energy beam EB2. [Figure 6C] 10 is a table showing conditions for the energy beam EB2. [Figure 6D] 10 is a table showing conditions for the energy beam EB2. [Figure 7] FIG. 10 is a schematic diagram showing an example of a configuration in which one rotating body has two regions. [Figure 8] FIG. 1 is a schematic diagram showing an example of a configuration in which a rotating body arranged as a first member and a rotating body arranged as a second member function as a debris reduction mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0030] First Embodiment Hereinafter, a first embodiment of the present technology will be described with reference to the drawings.

[0031] [Basic configuration of light source device] 1 is a schematic diagram showing an example of the configuration of a light source device 100 according to this embodiment. The light source device 100 is an LPP (Laser Produced Plasma) type light source device. That is, the light source device 100 is a device that irradiates a plasma raw material 101 with an energy beam EB to excite the plasma raw material 101 and generate plasma P, and extracts radiation R emitted from the plasma P to use as a light source. The radiation R is EUV (Extreme Ultraviolet) light, X-rays, or other electromagnetic waves.

[0032] The plasma raw material 101 is a molten metal or alloy, such as tin (Sn), lithium (Li), gadolinium (Gd), terbium (Tb), gallium (Ga), bismuth (Bi), indium (In) in a liquid phase, or an alloy containing at least one of these materials. The plasma raw material 101 corresponds to an embodiment of a liquid raw material.

[0033] FIG. 1 is a diagram showing a schematic cross section of the light source device 100 taken along the horizontal direction at a predetermined height from the installation surface, as viewed from vertically above. In FIG. 1, cross sections of parts that are not necessary to explain the cross-sectional configuration, etc., are omitted to facilitate understanding of the configuration and operation of the light source device 100. Hereinafter, the X direction may be referred to as the left-right direction of the horizontal 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-rear direction of the horizontal direction (the positive side of the Y axis is the front side, and the negative side is the back side), and the Z direction as the vertical direction (the positive side of the Z axis is the top side, and the negative side is the bottom side). Of course, the application of the present technology is not limited to the orientation in which the light source device 100 is used.

[0034] As shown in FIG. 1, the light source device 100 includes a housing 102, a vacuum chamber 103, an energy beam entrance chamber 104, a radiation exit chamber 105, a plasma generation mechanism 106, a control unit 107, and a beam source .

[0035] 1, the housing 102 has an exit hole 102a, an entrance hole 102b, and a through-hole 102c. In this embodiment, the exit axis EA of the radiation R is set to pass through the exit hole 102a. The radiation R is extracted along the exit axis EA and emitted from the exit hole 102a. In this embodiment, the entrance axis IA of the energy beam EB is set to pass through the entrance hole 102b.

[0036] 1, a beam source 108 that emits an energy beam EB is installed outside the housing 102. The beam source 108 is installed so that the energy beam EB enters the inside of the housing 102 along an incident axis IA. An electron beam or a laser beam can be used as the energy beam EB.

[0037] The light source device 100 is provided with a chamber section C including a plurality of chambers. Specifically, the chamber section C includes a vacuum chamber 103, an energy beam incident chamber (hereinafter simply referred to as an incident chamber) 104, and a radiation exit chamber (hereinafter simply referred to as an exit chamber) 105. The vacuum chamber 103 and the incident chamber 104 are connected to each other, and the vacuum chamber 103 and the exit chamber 105 are also connected to each other.

[0038] The entrance chamber 104 is configured to be located on an entrance axis IA of the energy beam EB, and the exit chamber 105 is configured to be located on an exit axis EA of the radiation R. A collector (condensing mirror) 112 that guides the radiation R is disposed within the exit chamber 105. Furthermore, a plasma generation mechanism 106 that generates plasma P is disposed within the vacuum chamber 103.

[0039] A utilization device such as a mask inspection device is connected to the end of the extraction chamber 105 opposite the plasma generation mechanism 106. In the example shown in FIG. 1, an application chamber 110 is connected as a chamber that forms part of the utilization device. The pressure inside the application chamber 110 may be atmospheric pressure. Furthermore, the inside of the application chamber 110 may be purged by introducing a gas (e.g., an inert gas) through a gas injection path as needed, and may be evacuated by an exhaust means (not shown). A filter film 111 and an opening are provided between the application chamber 110 and the extraction chamber 105 to physically separate the region where the plasma P is generated from the application chamber 110.

[0040] An entrance window 114 is provided in the chamber body 109. The entrance window 114 is arranged at a position aligned with the entrance hole 102b on the entrance axis IA of the energy beam EB. An exhaust pump 117 is also connected to the chamber body 109.

[0041] 1, the emission chamber 105 and the incidence chamber 104 are provided with gas injection paths 116a and 116b, respectively, and gas is supplied from a gas supply device (not shown) to the inside of the emission chamber 105 and the incidence chamber 104. A gas having a high transmittance to the radiation R, such as argon or helium, is supplied to the emission chamber 105. A gas having a high transmittance to the energy beam EB, such as argon or helium, is supplied to the incidence chamber 104.

[0042] The plasma generation mechanism 106 is a mechanism for generating plasma P in the vacuum chamber 103 and emitting radiation R (X-rays or EUV light). As shown in FIG. 1, the plasma generation mechanism 106 includes a rotating body 2, and an energy beam EB is incident on the rotating body 2. The rotating body 2 is disposed in the vacuum chamber 103 so that the irradiation position I of the energy beam EB is located at the intersection of the entrance axis IA and the exit axis EA.

[0043] The control unit 107 controls the operation of each component of the light source device 100. For example, the control unit 107 controls the operation of the beam source 108 and the exhaust pump 117. In Fig. 1, the control unit 107 is illustrated schematically as a functional block, but the position where the control unit 107 is configured may be designed arbitrarily.

[0044] 1, in this embodiment, a radiological diagnostic unit 119 is connected to the chamber body 109. The radiological diagnostic unit 119 is disposed at a position where the radiation R emitted in a direction different from the emission axis EA of the radiation R is incident, and measures the state of the radiation R emitted from the plasma P.

[0045] [Plasma generation mechanism] FIG. 2 (FIGS. 2A and 2B) is a schematic diagram showing an example of the configuration of the plasma generation mechanism 106. Figure 2 shows the plasma generation mechanism 106 shown in Figure 1 as viewed from the direction of arrow A. The plasma generation mechanism 106 has a shaft member 1, a rotor 2, a raw material container 3, and a motor 4. Of these, only the shaft member 1 and the rotor 2 are shown in Figure 2, and the raw material container 3 and motor 4 are not shown.

[0046] 1, the shaft member 1 is a rod-shaped member and is arranged parallel to the Y direction so as to penetrate the housing 102 and the vacuum chamber 103. In this example, a mechanical seal 8 or the like is provided at the penetrating portion of the vacuum chamber 103, allowing the shaft member 1 to rotate while maintaining the airtightness of the vacuum chamber 103.

[0047] The rotor 2 is a disk-shaped member and has a circular front surface 5, a back surface 6, and a side surface 7. The rotor 2 is placed inside the vacuum chamber 103 so that the center of the back surface 6 is connected to the end of the shaft member 1 on the vacuum chamber 103 side. The rotor 2 is placed perpendicular to the shaft member 1, that is, parallel to the XZ plane. The rotor 2 is made of a material that is corrosion-resistant to the plasma raw material 101 and has a certain rigidity, for example. The rotating body 2 corresponds to an embodiment of a first member according to the present technology.

[0048] The raw material container 3 is disposed so as to cover the underside of the rotor 2. There are no specific limitations on the shape of the raw material container 3, and it may have any shape that is capable of covering the underside of the rotor 2. Liquid plasma raw material 101 is stored in the raw material container 3, so that the underside of the rotor 2 is immersed in the plasma raw material 101.

[0049] For example, plasma raw material 101 is supplied to the raw material container 3 by a raw material supply mechanism (not shown), and the plasma raw material 101 is heated and melted by a heater or the like provided in the raw material container 3, thereby storing the liquid plasma raw material 101.

[0050] The motor 4 is arranged outside the housing so as to be connected to the end of the shaft member 1 on the outside side of the housing 102. The specific type of the motor 4 is not limited.

[0051] [Light source operation] The operation of the light source device 100 will now be described. The control unit 107 controls the driving of the motor 4, and the shaft member 1 and the rotating body 2 rotate together. In Figures 2A and 2B, the direction of rotation of the shaft member 1 and the rotating body 2 is indicated by arrows. In this example, they rotate clockwise when viewed from the positive side of the Y axis, but they may also rotate counterclockwise. Furthermore, the specific rotation speed is not limited.

[0052] The underside of the rotor 2 is immersed in liquid plasma raw material 101, so when the rotor 2 rotates, the plasma raw material 101 is lifted up while adhering to the surfaces (front surface 5, back surface 6, side surfaces 7) of the rotor 2. Therefore, the plasma raw material 101 adheres to the parts of the surface of the rotor 2 that are not immersed in the plasma raw material 101.

[0053] In this embodiment, under this condition, the energy beam EB1 shown in FIG. 2A and the energy beam EB2 shown in FIG. 2B are irradiated. The energy beams EB1 and EB2 have different focusing densities. Hereinafter, the focusing densities of the energy beams EB1 and EB2 may be referred to as the "first focusing density" and the "second focusing density," respectively. Furthermore, each of the energy beams EB1 and EB2 is irradiated as a pulse wave.

[0054] In this example, two beam sources 108 are used, and an energy beam EB1 is emitted from one beam source 108, and an energy beam EB2 is emitted from the other beam source 108. Note that the two beam sources 108 are not shown in Fig. 2, and in Fig. 1, the two beam sources 108 are schematically shown as one beam source 108, and the two energy beams EB1 and EB2 are schematically shown as one energy beam EB.

[0055] However, it is also possible to irradiate energy beams EB1 and EB2 with different focusing densities using one beam source 108. Specifically, an optical system may be configured between the beam source 108 and the rotating body 2, and the optical system may separate one energy beam EB into two energy beams EB1 and EB2 with different focusing densities.

[0056] In the example of Figure 2A, plasma raw material 101 is deposited to a predetermined thickness in region 9 located above surface 5 of rotor 2, and energy beam EB1 is irradiated obliquely with respect to a position inside region 9. Irradiation position I1 may be a point located inside region 9, or it may be an area with a certain extent included in region 9. However, this is not limiting, and irradiation may be performed on any region of surface 5 that is not immersed in plasma raw material 101. Region 9 corresponds to one embodiment of the first region according to the present technology. The film thickness of the region 9 corresponds to an embodiment of the first film thickness according to the present technology.

[0057] When the energy beam EB1 is irradiated, the plasma raw material 101 adhering at the irradiation position I1 diffuses (or evaporates). Figures 2A and 2B show a schematic diagram of the diffusion space 10 into which the plasma raw material 101 diffuses. In this example, the plasma raw material 101 diffuses toward the right of the irradiation position I1, and so the diffusion space 10 is also located to the right of the rotor 2. The diffusion space 10 corresponds to an embodiment of the first space according to the present technology.

[0058] Next, as shown in Fig. 2B, an energy beam EB2 is irradiated onto the diffusion space 10 from above in the figure. Then, at irradiation position I2, the energy beam EB2 is absorbed by the plasma raw material 101 that has diffused into the diffusion space 10, generating plasma P. Then, radiation R shown in Fig. 1 is generated. Note that radiation R is not shown in Fig. 2B.

[0059] 2A and 2B are alternately repeated to generate radiation R. That is, the pulsed energy beams EB1 and EB2 are alternately irradiated once each to continuously generate diffusion space 10, and a state in which plasma P and radiation R are generated in diffusion space 10 is maintained.

[0060] On the other hand, within the scope of feasibility of the present technology, irradiation may be performed, for example, by irradiating twice with the energy beam EB1 and then irradiating once with the energy beam EB2, or irregular irradiation may be performed. In addition, the specific irradiation angles of the energy beams EB1 and EB2 are not limited.

[0061] [Light concentration and film thickness] In this technique, the first focusing density of the energy beam EB1 is set as a focusing density at which the energy beam EB1 does not reach the rotating body 2 when the energy beam EB1 is irradiated onto the region 9. That is, at the irradiation position I1 in FIG. 2A , the energy beam EB1 reaches the surface and the interior of the film of the plasma raw material 101, but does not reach the surface 5 of the rotating body 2. If the energy beam EB1 reaches the surface 5 of the rotating body 2, traces such as discoloration or changes in the surface shape that differ from positions not irradiated with the energy beam EB1 will remain at the positions irradiated with the energy beam EB1 on the surface 5 of the rotating body 2. Therefore, if no discoloration or changes in the surface shape are observed at the positions irradiated with the energy beam EB1 on the surface 5 of the rotating body 2, it can be easily determined that the focusing density was such that the energy beam EB1 did not reach the rotating body 2.

[0062] On the other hand, the second focal density of the energy beam EB2 may be set to a value sufficient to obtain radiation R of the desired intensity. For example, the second focal density may be greater than the first focal density of the energy beam EB1. Alternatively, the second focal density may be a focal density at which the energy beam EB2 reaches the rotating body 2 when irradiated with the energy beam EB2 on the region 9. That is, although the energy beam EB2 does not actually directly irradiate the rotating body 2, the focal density may be such that, if it were assumed that the energy beam EB2 were directly irradiated, the energy beam EB2 would reach the surface and interior of the film of plasma raw material 101, and even reach the surface 5 of the rotating body 2. In this case, the first focal density is a value that does not allow the energy beam EB2 to reach the surface 5 and does not leave a trace of the energy beam on the surface 5, while the second focal density is a value that allows the energy beam EB2 to reach the surface 5 and leave a trace of the energy beam on the surface 5. Therefore, the second focal density is naturally greater than the first focal density.

[0063] Conversely, the second focusing density may be a focusing density at which the energy beam EB2 does not reach the rotating body 2 when irradiated onto the region 9. In this case, the second focusing density may be larger or smaller than the first focusing density.

[0064] The first and second focusing densities are set in consideration of the film thickness of region 9, etc. Specifically, the focusing density can be changed by changing the output of the energy beam EB or by changing the focal length with a lens. In addition, in order to adjust the film thickness that adheres to the rotor 2, recesses may be formed in the first region of the rotor 2. By forming recesses, it is possible to adjust the film thickness of the plasma raw material 101 that adheres to the rotor 2 to a larger value, and it is possible to make it more difficult for the energy beam EB1 to reach the surface 5 of the rotor 2.

[0065] Furthermore, if there is a desired size or shape of the diffusion space 10, the first light focusing density may be set taking these into consideration. For example, it is possible to increase the volume of the diffusion space 10 by increasing the first light focusing density. Furthermore, if there is a desired intensity of the radiation R, the second light focusing density may be set taking this into consideration. In addition, the specific values ​​of the first light focusing density and the second light focusing density and the setting criteria therefor may be arbitrary.

[0066] In this example, a skimmer (not shown) is placed on the rotor 2 to adjust the film thickness of the plasma raw material 101 in the region 9. The film thickness also depends on the type of plasma raw material 101, the rotation speed of the rotor 2, and other factors.

[0067] As described above, in the light source device 100 according to this embodiment, the energy beam EB1 is irradiated at a first focusing density onto the region 9 where the plasma raw material 101 is deposited to a predetermined thickness, and the energy beam EB2 is irradiated at a second focusing density onto the diffusion space 10. The first focusing density is a focusing density at which the energy beam EB1 does not reach the rotor 2 when irradiated onto the region 9. This suppresses damage to the rotor 2, extends the life of the rotor 2, and makes it possible to improve the stability of the output of the radiation R.

[0068] Regardless of the application, such as inspection, light sources always require higher output power to improve the performance of the devices they are used for. This is also true for EUV light sources. In order to increase the output power of EUV light, the LPP method using a rotating body requires supplying the minimum amount of liquid metal necessary to suppress the amount of debris generated, and then heating it with a high-intensity laser to generate plasma.

[0069] As long as the energy conversion efficiency from the laser to EUV is maintained, increasing the laser power will allow for more EUV energy to be extracted. However, increasing the laser power increases the load on the base material, causing deformations such as dents on the surface of the base material. This makes it difficult to achieve stable, continuous emission of EUV light.

[0070] In addition, the laser is irradiated onto the molten raw material (target), but simply irradiating the laser does not allow for control of the density distribution of the target, and since it is not possible to match the laser wavelength with the critical density, the laser is not efficiently absorbed by the plasma, which results in unstable EUV light output.

[0071] On the other hand, methods that do not use a base material, such as directly irradiating the droplet raw material with a laser, are also possible, but this requires adjusting the irradiation position at a level of several microns to several tens of microns, making such adjustments extremely difficult.

[0072] In this technology, the first focusing density of the energy beam EB1 irradiated onto the rotating body 2 is set to a focusing density that prevents the energy beam EB1 from reaching the rotating body 2, thereby making it possible to significantly reduce the load that the energy beam EB1 imparts to the rotating body 2. By using the method of this technology, deformation of the rotating body 2 is prevented, and the output of the radiation R can be stabilized.

[0073] The main energy beam EB2 is also irradiated onto the diffusion space 10. The plasma raw material 101 diffused into the diffusion space 10 changes into a state similar to vapor or weakly ionized plasma, so when the plasma raw material 101 reaches a target density that matches the wavelength of the energy beam EB2 and is then irradiated with the energy beam EB2, the energy beam EB2 is sufficiently absorbed, generating plasma P. This makes it possible to maintain luminous efficiency while irradiating a location away from the rotating body 2 with the energy beam EB2.

[0074] Furthermore, because the film of plasma raw material 101 adhering to rotor 2 is rotating, even if irradiation with energy beam EB1 causes the plasma raw material 101 to diffuse and the surface of the film to become concave, the rotation quickly causes a smooth surface to appear again at irradiation position I1, so the energy beam EB1 is always irradiated onto a smooth surface. Therefore, plasma raw material 101 always diffuses in the same way, and the shape of diffusion space 10 always remains the same. Furthermore, irradiation position I2 is located no more than approximately 0.5 cm away from irradiation position I1. This makes it easy to adjust irradiation position I2.

[0075] In this technology, the energy beams EB1 and EB2 are irradiated as pulse waves, and are irradiated alternately once each, which prevents the plasma raw material 101 from remaining undiffused at the irradiation position I2 and makes it possible to stabilize the output of the radiation R.

[0076] <Second embodiment> A more detailed embodiment of the light source device 100 according to the present technology will be described as a second embodiment. In the following description, the description of the same parts as those in the configuration and operation of the light source device 100 described in the above embodiment will be omitted or simplified.

[0077] [Revolved body variations] FIG. 3 is a schematic diagram showing a variation example of the rotating body 2. 2A and 2B, another rotating body 12 is used. Rotating body 12 is a disk-shaped rotating body having a similar configuration to rotating body 2, and in this example, when viewed from the positive side of the Z axis, rotating body 2 is disposed on the left side and rotating body 12 is disposed on the right side.

[0078] Rotating body 2 is arranged so as to be tilted slightly counterclockwise when viewed from the positive side of the Z axis from a state parallel to the XZ plane, and rotating body 12 is arranged so as to be tilted slightly clockwise. The right end of rotating body 2 and the left end of rotating body 12 face each other with a gap between them. The rotating body 12 corresponds to an embodiment of a second member different from the first member according to the present technology.

[0079] In this embodiment, the rotors 2 and 12 rotate in opposite directions. Specifically, when viewed from the surface of the rotors 2 and 12 (the side without the shaft member), the rotor 2 rotates counterclockwise and the rotor 12 rotates clockwise. In Figure 3, the direction of rotation is indicated by an arrow.

[0080] Energy beam EB1 having a first focused density is irradiated from the upper right to the lower left of the figure onto region 13 located on side surface 7 of rotor 2. Region 13 is located roughly near the right end of side surface 7, and plasma raw material 101 is deposited in region 13 with a predetermined film thickness. The region 13 corresponds to an embodiment of the first region according to the present technology. The film thickness of the region 13 corresponds to an embodiment of the first film thickness according to the present technology.

[0081] Furthermore, an energy beam EB3 having a third focused density is irradiated from the upper left to the lower right onto region 15 located on side surface 14 of rotor 12. Region 15 is located roughly near the left end of side surface 14, and plasma raw material 101 is deposited in region 15 to a predetermined thickness. The thickness of region 15 may be the same as or different from that of region 13. Region 15 corresponds to an embodiment of the second region according to the present technology. The film thickness of the region 15 corresponds to an embodiment of the second film thickness according to the present technology.

[0082] The third focusing density is set as a focusing density at which the energy beam EB3 does not reach the rotating body 12 when the energy beam EB3 is irradiated onto the region 15. The third focusing density may be the same as or different from the first focusing density. The energy beams EB1 and EB3 may be irradiated simultaneously or at different times.

[0083] Irradiation with energy beam EB1 diffuses plasma raw material 101, creating diffusion space 16. Irradiation with energy beam EB3 creates diffusion space 17. In FIG. 3, diffusion spaces 16 and 17 are shown schematically without any pattern. Also, common space 18, which is the common portion (overlapping portion) of diffusion spaces 16 and 17, is shown schematically with a polka dot pattern. In common space 18, plasma raw material 101 is more densely diffused than in diffusion spaces 16 and 17.

[0084] In this example, the diffusion spaces 16 and 17 have the same shape, but they may have different shapes. The diffusion space 16 corresponds to an embodiment of the first space according to the present technology. The diffusion space 17 corresponds to an embodiment of the second space according to the present technology. The common space 18 corresponds to one embodiment of a space that is a common portion according to the present technology.

[0085] In this state, an energy beam EB2 having a second focused density is irradiated into the common space 18. Note that the energy beam EB2 is not shown in Fig. 3. The energy beam EB2 is irradiated, for example, from the front side to the back side of the figure, but may also be irradiated from the top side to the bottom side, etc.

[0086] The second focusing density may be a focusing density such that, if the energy beam EB2 is irradiated onto region 13, the energy beam EB2 does not reach the rotating body 2, and if the energy beam EB2 is irradiated onto region 15, the energy beam EB2 does not reach the rotating body 12. On the other hand, the second focusing density may be a focusing density such that the energy beam EB2 reaches the rotating body 2 or the rotating body 12. In other words, the value of the second focusing density may be larger or smaller than the values ​​of the first focusing density and the third focusing density.

[0087] According to this example, energy beam EB2 is irradiated onto common space 18, which is a space in which plasma raw material 101 is densely diffused, making it possible to obtain even more intense radiation R. For example, if energy beam EB2 is irradiated onto a single diffusion space 16 or 17 created by a single energy beam EB1 or EB3, the amount of plasma raw material 101 ejected into diffusion space 16 or 17 may be small, making it impossible to obtain a sufficient output of radiation R. In such cases, a method such as this example is effective.

[0088] The three energy beams EB1, EB2, and EB3 may be emitted from three different beam sources 108, respectively, or may be generated by combining two or less beam sources 108 with an optical system.

[0089] The distance between the rotors 2 and 12 (arrows in FIG. 3 ) may be adjusted as appropriate. By adjusting the distance, it is possible to change the size of the common space 18. Furthermore, if the distance is too far, the diffusion spaces 16 and 17 do not meet, and the common space 18 does not form. In such cases, the distance may be adjusted to be narrower. Alternatively, the distance may be made extremely small so that the rotors 2 and 12 form an inverted V shape.

[0090] FIG. 4 is a schematic diagram showing a variation example of the rotating body 2. In this example, the rotating bodies 2 and 12 are configured to be rotatable around a common shaft member 1 as a rotation axis. Specifically, the rotating body 2 is disposed on the left side of the figure, and the rotating body 12 is disposed on the right side, both parallel to the XZ plane. Furthermore, one shaft member 1 is disposed parallel to the Y direction so as to pass through the centers of the rotating bodies 2 and 12. When the shaft member 1 rotates, the rotating bodies 2 and 12 rotate integrally in the same direction.

[0091] Energy beam EB1 is irradiated from the upper right to the lower left of the figure onto the upper part of surface 21 on the right side of rotor 2. Energy beam EB3 is irradiated from the upper left to the lower right of the figure onto the upper part of surface 22 on the left side of rotor 12. Diffusion spaces 16 and 17 are then generated in each of these, and energy beam EB2 is irradiated onto common space 18. Note that the diffusion spaces 16 and 17, common space 18, and energy beam EB2 are not shown in FIG. 4. These may also be omitted in the subsequent figures.

[0092] In this example, two rotating bodies 2 and 12 can be rotated using one shaft member 1 and one motor 4, making it possible to realize a configuration using the rotating bodies 2 and 12 with an even simpler configuration.

[0093] 5A and 5B are schematic diagrams showing variations of the rotating body 2. FIG. In this example, rotors 2 and 12 are arranged to form a V-shape. Rotor 2 rotates clockwise when viewed from surface 5, and rotor 12 rotates counterclockwise when viewed from surface 24. Energy beam EB1 is irradiated near the right end of surface 5 of rotor 2, and energy beam EB3 is irradiated near the left end of surface 24 of rotor 12.

[0094] In Fig. 5A, both energy beams EB1 and EB3 are irradiated from the upper side of the figure. On the other hand, in Fig. 5B, energy beam EB1 is irradiated from the upper right to the lower left, and energy beam EB3 is irradiated from the upper left to the lower right. Energy beam EB2 is irradiated onto common space 18, and radiation R emitted from common space 18 to the lower side of the figure is collected.

[0095] By adopting an arrangement such as this example, it is possible to reduce the amount of debris that is released to the lower side of the figure from the common space 18. For example, this type of configuration is used in cases where it is acceptable for some debris to be released to the upper side, but it is desired to prevent debris from being released to the lower side.

[0096] In the variations of Figures 4, 5A, and 5B, region 13 irradiated with energy beam EB1 is located on surface 21 or 5 of rotor 2. Region 15 irradiated with energy beam EB3 is located on surface 22 or 24 of rotor 12. On the other hand, in the variation of Figure 3, region 13 is located on side surface 7 of rotor 2, and region 15 is located on side surface 14 of rotor 12.

[0097] Also, in the variations of Figures 3, 4, and 5B, the energy beams EB1 and EB3 intersect with each other, while in the variation of Figure 5A, the energy beams EB1 and EB3 do not intersect with each other.

[0098] Depending on the arrangement of the rotors 2 and 12 and other mechanisms, the irradiation position I and irradiation angle of the energy beams EB1 and EB3 may be limited. In addition, it may be necessary to adjust the irradiation position I to generate the common space 18 at a desired position. With this technology, the energy beams EB1 and EB3 can be irradiated onto either the front or side surface, and it is also possible to select whether or not they intersect with each other, making it possible to adopt a configuration suitable for various situations.

[0099] Even when only one rotating body 2 is used, the energy beam EB1 may be irradiated onto the side surface 7 in the same manner. Alternatively, the energy beam EB1 may be irradiated onto the rear surface 6 of the rotating body 2.

[0100] There are no other limitations on the specific arrangement of the rotors 2 and 12. Alternatively, three or more rotors may be arranged, and each may be irradiated with one energy beam EB, for a total of three or more.

[0101] <Other embodiments> The present technology is not limited to the above-described embodiments, and various other embodiments can be realized.

[0102] [Conditions for energy beam EB2] 6A to 6D are tables showing the conditions of the energy beam EB2. FIG. 6A shows whether or not a plasma P with sufficient emission intensity is generated when the pulse width of the energy beam EB2 is 10 ns. The row components of the table represent the pulse energy (J) of the energy beam EB2, and the column components represent the spot size (μm). Here, the spot size is the value when the intensity of the energy beam EB2 is 1 / e of its peak value. 2 where e is the natural logarithm and the energy beam EB2 is assumed to be a Gaussian beam.

[0103] Each box in the table is marked with "O" if irradiation with the energy beam EB2 generates plasma P with sufficient luminous intensity, and marked with "X" if it does not. For example, when the pulse width is 10 ns, the pulse energy is 0.05 J, and the spot size is 300 μm, plasma P with sufficient luminous intensity is generated.

[0104] Similar tables are shown in Figure 6B for a pulse width of 5 ns, Figure 6C for a pulse width of 2 ns, and Figure 6D for a pulse width of 1 ns for the energy beam EB2. The shorter the pulse width of the energy beam EB2, the greater the pulse energy, or the smaller the spot size, the higher the irradiation intensity, which tends to generate plasma P with sufficient emission intensity.

[0105] In any of Figures 6A to 6D, Pulse energy is 0.005J or more and less than 0.02J, and the spot size is 100μm or less. Pulse energy is 0.02J or more and less than 0.05J, and the spot size is 200μm or less. Pulse energy is 0.05J or more and less than 0.15J, and the spot size is 300μm or less. Pulse energy of 0.15 J or more and spot size of 600 μm or less In other words, if the pulse width of the energy beam EB2 is 10 ns or less, the pulse energy is 0.005 J or more, and each of the above conditions is met, plasma P with sufficient emission intensity is generated.

[0106] 6A to 6D, squares with a pulse energy of 0.15 J or more are marked with a circle. That is, when the pulse width of the energy beam EB2 is 10 ns or less, the pulse energy is 0.15 J or more, and the spot size is 600 μm or less, plasma P with sufficient emission intensity is generated.

[0107] 6A to 6D, squares with a spot size of 100 μm or less are marked with a circle. That is, when the pulse width is 10 ns or less, the pulse energy is 0.005 J or more, and the spot size is 100 μm or less, plasma P with sufficient emission intensity is generated.

[0108] [Shape of the rotating body, etc.] The specific shape of the rotor 2 is not limited, and it may be a shape other than a disk. Furthermore, the member corresponding to the rotor 2 may be a non-rotating member. For example, the member may be plate-shaped, and rather than the lower part of the member being immersed in the plasma raw material 101, liquid plasma raw material 101 may be poured onto the member from above, resulting in a state in which plasma raw material 101 adheres to the surface of the member in a predetermined film thickness.

[0109] On the other hand, in this embodiment, the use of the rotor 2 as a member makes it possible to stably attach the plasma raw material 101. Furthermore, the rotor 2 having a disk shape makes it possible to stabilize the rotational operation.

[0110] Furthermore, the rotor 2 may be covered with a cover structure to prevent debris from scattering to the outside. In this case, for example, a space large enough to allow the diffusion space 10 to exist is provided between the rotor 2 and the cover structure.

[0111] [Irradiating different areas of the same component] In the example of Fig. 3 etc., the regions 13 and 15 irradiated with the energy beams EB1 and EB3 are located on different rotating bodies 2 and 12, respectively. However, this is not limiting, and the two different regions may be located on the same member.

[0112] 7 is a schematic diagram showing an example of a configuration in which one rotating body 30 has two regions 31 and 32. Note that this figure differs from FIGS. 2A and 2B in that the rotating body 30 is viewed from the positive side in the Z direction. In this example, an energy beam EB1 is irradiated onto a region 31 of the rotating body 30, creating a diffusion space 33. An energy beam EB3 is irradiated onto a region 32, creating a diffusion space 34. Regions 31 and 32 are both located on the circumference of a surface 35 of the rotating body 30. That is, in FIG. 7A, regions 31 and 32 are located on the front side of the page of surface 35.

[0113] An energy beam EB2 (not shown) is irradiated from the front side of the page to a common space 36, which is a space where the regions 31 and 32 overlap. By irradiating the energy beams EB1 and EB3 to the different regions 31 and 32 of one rotating body 30 as in this example, it is possible to obtain high-intensity radiation R with a simple configuration.

[0114] In this example, the first and third condensation densities of the energy beam EB1 and EB3 may be the same or different. The shape of the member corresponding to the rotating body 2 is not limited.

[0115] [Debris Mitigation Mechanism] FIG. 8 is a schematic diagram showing an example of a configuration in which a rotor 2 arranged as a first member and a rotor 12 arranged as a second member function as a debris reduction mechanism. FIG. 8 is a schematic diagram of the exit chamber 105 of FIG.

[0116] In this example, a certain amount of gap is provided between the two rotating bodies 2 and 12, and when an energy beam EB2 (both not shown) is irradiated onto the common space 18, radiation R passes through the gap and is emitted toward the bottom of the figure.

[0117] In this state, neither region 13 of rotor 2 nor region 15 of rotor 12 faces exit chamber 105. That is, the direction of the normal to region 13 (upper right) and the direction of the normal to region 15 (upper left) are both tilted by 90° or more with respect to the direction of exit axis R1 (downward). In Figure 8, each direction is indicated by an arrow.

[0118] In this embodiment, debris is generated by irradiation with energy beams EB1 to EB3, but the debris heading toward the bottom of the figure is blocked to some extent by rotors 2 and 12. This makes it possible to reduce the impact of debris on components located below the figure, such as extraction chamber 105. In other words, rotors 2 and 12 function as a debris reduction mechanism.

[0119] Note that a similar configuration may be employed even when only the first member is disposed, i.e., when only one rotator 2 is disposed. That is, for example, a configuration in which the rotator 12 and EB3 are not present in FIG. 8 may be employed. In this case, too, the region 13 does not face the extraction chamber 105, and the rotator 2 reduces the scattering of debris to the lower left side of the figure. Alternatively, any configuration may be employed in which the extraction chamber 105 is disposed on the extraction axis R1 and the region 13 does not face the extraction chamber 105. Furthermore, in this example, the first member or the second member does not have to be a rotator, and the shape of the member is not limited.

[0120] [Preheating] After the diffusion space 10 is created, the diffusion space 10 may be irradiated with an energy beam EB having a low light concentration density to preheat the diffused plasma raw material 101, and then the energy beam EB2 may be irradiated in the preheated state. This makes it possible to further increase the output of the radiation R.

[0121] 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]

[0122] EB...energy beam 1...Shaft member 2, 12...rotating body 5, 21, 22, 24…Surface 7, 14...Side 9, 13, 15…area 10, 16, 17... Diffusion space 18…Common space 100...Light source device 101...Plasma raw material 105...Exit chamber 108...Beam source

Claims

1. A light source device that converts a liquid raw material into plasma by irradiating it with an energy beam to extract radiation, a first member having a first region to which the liquid source is attached with a first film thickness; a beam source that irradiates the first region with the energy beam at a first light concentration density, and irradiates a first space, which is a space into which the liquid raw material has been diffused by irradiation at the first light concentration density, with the energy beam at a second light concentration density; Equipped with The first light concentration density is a light concentration density at which the energy beam does not reach the first member when the energy beam is irradiated onto the first region. Light source device.

2. The light source device according to claim 1 , the beam source irradiates the energy beam at a third light concentration density onto a second region, which is different from the first region and on which the liquid raw material is deposited with a second film thickness, and irradiates the energy beam at the second light concentration density onto a space that is a common portion between the first space and a second space, which is a space into which the liquid raw material has been diffused by irradiation at the third light concentration density; The third light concentration density is a light concentration density at which the energy beam does not reach the second member when the energy beam is irradiated onto the second region. Light source device.

3. The light source device according to claim 2, further comprising: a second member different from the first member, the second member having the second region; Light source device.

4. 3. The light source device according to claim 1, The first member is a disk-shaped rotating body. Light source device.

5. The light source device according to claim 3, The first member and the second member are each a disk-shaped rotating body. Light source device.

6. The light source device according to claim 5 , the first region is located on a circular surface of the first member; The second region is located on a circular surface of the second member. Light source device.

7. 7. The light source device according to claim 5, the first region is located on a side surface of the first member; The second region is located on a side surface of the second member. Light source device.

8. 6. The light source device according to claim 3 or 5, The beam source emits the energy beam of the first light density and the energy beam of the third light density so that they intersect with each other. Light source device.

9. 6. The light source device according to claim 3 or 5, The beam source emits the energy beam of the first light density and the energy beam of the third light density so as not to intersect with each other. Light source device.

10. 7. The light source device according to claim 5, The first member and the second member are both rotatable about a common shaft member as a rotation axis. Light source device.

11. 4. The light source device according to claim 1, the beam source irradiates the energy beam of the first light density and the energy beam of the second light density as pulse waves, The energy beam having the first light density and the energy beam having the second light density are alternately irradiated once each. Light source device.

12. The light source device according to claim 11, The energy beam irradiated at the second focusing density has a pulse width of 10 ns or less and a pulse energy of 0.005 J or more, and When the pulse energy is 0.005 J or more and less than 0.02 J, the intensity of the energy beam is 1 / e of the peak value, where e is the natural logarithm. ２ The spot size, which is the diameter of the part where the beam is doubled, is 100 μm or less, When the pulse energy is 0.02 J or more and less than 0.05 J, the spot size is 200 μm or less; When the pulse energy is equal to or greater than 0.05 J and less than 0.15 J, the spot size is equal to or less than 300 μm; When the pulse energy is 0.15 J or more, the spot size is 600 μm or less. Light source device.

13. The light source device according to claim 12, The energy beam irradiated at the second focusing density has a pulse width of 10 ns or less, a pulse energy of 0.15 J or more, and a spot size of 600 μm or less; Alternatively, the pulse width is 10 ns or less, the pulse energy is 0.005 J or more, and the spot size is 100 μm or less. Light source device.

14. 4. The light source device according to claim 1, further comprising: an exit chamber disposed on an exit axis of the radiation; The first member is positioned so that the first region does not face the emission chamber. Light source device.

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