Plasma generating mechanism and light source apparatus
The plasma generation mechanism addresses the challenges of high energy consumption and costly materials in EUV light source devices by melting solid plasma raw materials only when needed, resulting in a cost-effective and durable solution for plasma generation.
Patent Information
- Application Number
- JP2023185539
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-10-30
- Publication Date
- 2025-05-14
AI Technical Summary
Existing EUV light source devices face challenges in efficiently supplying plasma raw materials, requiring high energy for melting and using expensive corrosion-resistant materials and valves, which leads to increased costs and reduced durability.
A plasma generation mechanism that includes a rotating body, a rotary driving source, a reservoir, a heating section, and a raw material supply section, where solid plasma raw materials are input and melted only when needed, reducing energy consumption and the need for expensive corrosion-resistant materials and valves.
The solution achieves a low-cost and highly durable plasma generation mechanism by minimizing energy requirements for melting plasma raw materials and reducing the need for expensive materials and valves, thereby enhancing the overall efficiency and longevity of the EUV light source device.
Smart Images
Figure 2025074606000001_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to a plasma generating mechanism and a light source device that supply plasma raw material to an energy beam irradiation position and generate plasma. [Background technology]
[0002] Traditionally, X-rays have been used for medical, industrial, and research purposes. In the medical field, X-rays are used for chest X-ray photography, dental X-ray photography, and CT (Computer Tomogram). In the industrial field, X-rays are used for non-destructive testing to observe the inside of materials such as structures and welds, and non-destructive tomographic testing. In the research field, X-rays are used for X-ray diffraction to analyze the crystal structure of materials, and X-ray spectroscopy (fluorescence X-ray analysis) to analyze the constituent elements of materials. 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.
[0003] Some EUV light source devices generate EUV light by irradiating and exciting a plasma raw material such as molten tin or lithium with an energy beam to generate high-temperature plasma, from which EUV light is extracted. A method that uses laser light as an energy beam is called LPP (Laser Produced Plasma), and a method that uses discharge is called DPP (Discharge Produced Plasma) or LDP (Laser Assisted Discharge Produced Plasma).
[0004] Known LPP-type EUV light source devices generate plasma by exciting the raw material by focusing laser light on droplets of the plasma raw material. In contrast, a method has been developed in recent years to supply plasma raw material to an irradiation area of laser light by using the centrifugal force of a rotor (see, for example, Patent Document 1). In this method, the rotor rotates with its lower part immersed in the stored plasma raw material, so that the plasma raw material adheres to the surface of the rotor and the plasma raw material is supplied to the irradiation area on the rotor surface. This method does not require the plasma raw material to be supplied as droplets, and therefore can obtain high-brightness radiation with a relatively simple configuration compared to the method of focusing laser light on droplets. [Prior art documents] [Patent documents]
[0005] [Patent Document 1] JP 2014-216286 A Summary of the Invention [Problem to be solved by the invention]
[0006] In an EUV light source device such as that described in Patent Document 1, the method of supplying the plasma raw material to the storage tank is problematic. In a method of circulating a large amount of plasma raw material between the storage tank and the raw material supply mechanism as in Patent Document 1, a large amount of energy is required to melt the plasma raw material. In addition, the path along which the molten plasma raw material circulates must be made of a material or coating that is resistant to corrosion by the plasma raw material, which increases costs.
[0007] On the other hand, if the plasma raw material is not circulated and only the plasma raw material stored in the storage tank is used, the large amount of energy described above is unnecessary, but the need to replenish the plasma raw material remains. In addition, the supply path for the plasma raw material must be at or above the melting point, and the supply path must use materials or coatings that are corrosion-resistant to the plasma raw material. Furthermore, the supply path must use expensive heat-resistant valves, and even if they are heat-resistant, their lifespan will inevitably be shortened.
[0008] In view of the above circumstances, an object of the present invention is to provide a plasma generating mechanism and a light source device which are low-cost and highly durable in relation to the supply of plasma raw material. [Means for solving the problem]
[0009] In order to achieve the above-mentioned object, a plasma generation mechanism according to one embodiment of the present invention is a plasma generation mechanism provided in a light source device that converts a liquid plasma raw material, which is a molten plasma raw material, into plasma by irradiating it with an energy beam to extract radiation, and is provided with a rotating body, a rotation drive source, a reservoir, a heating unit, and a raw material supply unit. The rotating body rotates around a rotation axis. The rotary drive source rotates the rotor about the rotation axis. The storage tank stores the liquid plasma raw material, and a portion of the rotor is immersed in the stored liquid plasma raw material. The heating section heats the liquid plasma raw material stored in the reservoir. The raw material supply section has a raw material inlet passage through which a solid plasma raw material, which is the plasma raw material in a solid state, passes, and a raw material supply port that is provided in the raw material inlet passage and through which the solid plasma raw material cannot pass but the liquid plasma raw material formed by melting the solid plasma raw material can pass, and the liquid plasma raw material that passes through the raw material supply port flows into the reservoir.
[0010] According to this configuration, when solid plasma raw materials are fed into the raw material introduction passage in the raw material supply section, the solid plasma raw materials cannot pass through the raw material supply port, and only the liquid plasma raw materials generated by melting pass through the raw material supply port and flow into the storage tank. When liquid plasma raw materials are supplied to the plasma generation mechanism, a large amount of energy is required to maintain the molten state of the plasma raw materials, but by supplying solid plasma raw materials and melting them only when they are supplied to the storage tank, it is possible to reduce the amount of energy required. In addition, some molten metals are corrosive, and therefore it is necessary to use a corrosion-resistant coating or corrosion-resistant material, but it is possible to reduce the number of places where they are used, and costs can be reduced. Furthermore, no valves are required to control the liquid plasma raw materials, and high durability can be achieved.
[0011] The raw material supply port may be configured so that the solid plasma raw material does not come into contact with the liquid surface of the liquid plasma raw material stored in the storage tank, or so that only the lower end of the solid plasma raw material comes into contact with the liquid surface.
[0012] The raw material supply port may have a maximum width smaller than a minimum width of the solid plasma raw material.
[0013] The heating section may further heat and melt the solid plasma raw material located in the raw material inlet passage.
[0014] The raw material supply unit may include an outer periphery member that forms an outer periphery of the cylindrical raw material inlet path, and a stopper that is provided at an end of the raw material inlet path on the storage tank side and that keeps the solid plasma raw material inside the raw material inlet path.
[0015] The heating section may further heat and melt the solid plasma raw material held by the stopper.
[0016] The rotating body may have a surface of rotation on which the energy beam is incident.
[0017] The raw material supply section may be provided on a rear side of the rotation surface of a cover member that houses the rotor and forms the storage tank.
[0018] The radiation may be extreme ultraviolet light or x-rays.
[0019] The plasma feedstock may be tin, lithium, gadolinium, terbium, gallium, bismuth, indium, or an alloy containing at least one of these materials.
[0020] In order to achieve the above-mentioned object, a light source device according to one embodiment of the present invention is a light source device that converts a liquid plasma raw material, which is a molten plasma raw material, into plasma by irradiating it with an energy beam to extract radiation, and is equipped with a plasma generation mechanism and a beam source. The plasma generation mechanism comprises a rotor that rotates about a rotation axis, a rotary drive source that rotates the rotor about the rotation axis, a storage tank that stores the liquid plasma raw material and in which a portion of the rotor is immersed in the stored liquid plasma raw material, a heating unit that heats the liquid plasma raw material stored in the storage tank, a raw material inlet path through which a solid plasma raw material, which is the plasma raw material in a solid state, passes, and a raw material supply unit that is provided in the raw material inlet path and has a raw material supply port through which the solid plasma raw material cannot pass but through which the liquid plasma raw material formed by melting the solid plasma raw material can pass, and through which the liquid plasma raw material that has passed through the raw material supply port flows into the storage tank. The beam source directs the energy beam onto the surface of rotation. Effect of the Invention
[0021] According to the present invention, it is possible to provide a plasma generating mechanism and a light source device which are low-cost and highly durable in relation to the supply of plasma raw material. [Brief description of the drawings]
[0022] [Figure 1] 1 is a schematic diagram of a light source device according to an embodiment of the present invention. [Diagram 2]3 is a schematic diagram of a plasma generating mechanism included in the light source device. FIG. [Diagram 3] FIG. 2 is a schematic diagram showing the supply of liquid plasma raw material from the raw material supply unit. [Figure 4] FIG. 2 is a cross-sectional view of the rotating body unit. [Diagram 5] FIG. 2 is a cross-sectional view of the rotating body unit. [Figure 6] FIG. 2 is a schematic diagram showing a configuration of the raw material supply port. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] A light source device according to an embodiment of the present invention will be described.
[0024] [Basic configuration of light source device] Fig. 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 a light source device of the LPP (Laser Produced Plasma) type. That is, as shown in Fig. 2, the light source device 100 is a device that irradiates a liquid plasma raw material 101 with an energy beam EB to excite the liquid plasma raw material 101 to 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.
[0025] The liquid plasma raw material 101 is a molten metal or alloy, such as liquid-phase tin (Sn), lithium (Li), gadolinium (Gd), terbium (Tb), gallium (Ga), bismuth (Bi), indium (In), or an alloy containing at least one of these materials. When EUV light is emitted as the radiation R, molten Sn or Li is used as the liquid plasma raw material 101. When X-rays are emitted as the radiation R, molten Ga, Ga alloy, Sn compound, or the like is used as the liquid plasma raw material 101.
[0026] FIG. 1 is a schematic cross-section of the light source device 100 cut along the horizontal direction at a position of a predetermined height from the installation surface, as viewed from vertically above. In FIG. 1, in order to facilitate understanding of the configuration and operation of the light source device 100, cross-sections are omitted for parts that do not require explanation of the cross-sectional configuration, etc. In the following description, the X direction is 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 is 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 rear side), and the Z direction is the vertical direction (the positive side of the Z axis is the upper side, and the negative side is the lower side). Of course, the application of this technology is not limited to the direction in which the light source device 100 is used, etc.
[0027] As shown in FIG. 1, a 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 generating mechanism 106, a control unit 107, and a beam source .
[0028] 1, the housing 102 has an exit hole 102a, an entrance hole 102b, and a through hole 102c. In this embodiment, an 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, an entrance axis IA of the energy beam EB is set to pass through the entrance hole 102b.
[0029] 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.
[0030] 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 connected to each other.
[0031] 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 (light-collecting mirror) 112 that guides the radiation R is disposed in the exit chamber 105. Also, a plasma generation mechanism 106 that generates plasma P is disposed in the vacuum chamber 103.
[0032] A utilization device such as a mask inspection device is connected to the end of the emission chamber 105 opposite to the plasma generation mechanism 106. In the example shown in FIG. 1, an application chamber 110 is connected as a chamber forming a part of the utilization device. The pressure in the application chamber 110 may be atmospheric pressure. The inside of the application chamber 110 may be purged by introducing a gas (e.g., an inert gas) from a gas injection path as necessary. The gas in the application chamber 110 may be exhausted by an exhaust means not shown. A filter film 111 is provided between the application chamber 110 and the emission chamber 105 to physically separate the area where the plasma P is generated from the application chamber 110.
[0033] The chamber body 109 is provided with an entrance window 114. 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. In addition, an exhaust pump 117 is connected to the chamber body 109.
[0034] 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.
[0035] 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 120, and an energy beam EB is incident on the rotating body 120. The rotating body 120 is disposed in the vacuum chamber 103 such that an irradiation position I of the energy beam EB is located at the intersection of an entrance axis IA and an exit axis EA. The plasma generation mechanism 106 will be described in detail later.
[0036] 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. The control unit 107 has hardware circuits necessary for a computer, such as a CPU and memory (RAM, ROM). The CPU loads a control program stored in the memory into the RAM and executes it, thereby executing various processes. A device such as a PLD (Programmable Logic Device) may be used as the control unit 107. In FIG. 1, the control unit 107 is illustrated diagrammatically as a functional block, but the position where the control unit 107 is configured may be designed arbitrarily.
[0037] 1, in this embodiment, a radiation diagnostic unit 119 is connected to the chamber body 109. The radiation diagnostic unit 119 is disposed at a position where 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.
[0038] [Configuration of plasma generation mechanism] As described above, 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). Fig. 2 is a schematic diagram of the plasma generation mechanism 106. As shown in the figure, the plasma generation mechanism 106 includes a rotor 120, a rotary drive source 131, a shaft portion 132, and a storage tank 133.
[0039] The rotary drive source 131 is disposed outside the vacuum chamber 103, and generates rotational power for the rotor 120. The rotary drive source 131 is, for example, a motor. The shaft 132 penetrates the chamber body 109 and the housing 102, connects the rotary drive source 131 and the rotor 120, and transmits the rotational power generated in the rotary drive source 131 to the rotor 120. The shaft 132 is rotatably supported by a mechanical seal 134. The storage tank 133 is disposed vertically below the rotor 120, and stores the liquid plasma raw material 101.
[0040] The rotating body 120 is disposed in the vacuum chamber 103 and is connected to a shaft portion 132. The rotating body 120 rotates by the rotation of the shaft portion 132, as shown by an arrow S1 in Fig. 2. Hereinafter, the rotation axis of the rotating body 120 and the shaft portion 132 is referred to as a rotation axis M.
[0041] As shown in Fig. 2, the rotor 120 has a disk shape. Hereinafter, the surface of the rotor 120 opposite the shaft 132 will be referred to as the rotation surface 120a. The rotation axis M is, for example, parallel to the horizontal direction (XY direction), and the rotation surface 120a is arranged so that it is parallel to the vertical direction. A part of the rotation surface 120a is immersed in the liquid plasma raw material 101 stored in the storage tank 133, and the liquid plasma raw material 101 adheres to the rotation surface 120a as the rotor 120 rotates. The liquid plasma raw material 101 adhered to the rotation surface 120a is transported to the irradiation position I as shown by the arrow S2 in the figure as the rotor 120 rotates, and is converted into plasma by the energy beam EB irradiated to the irradiation position I.
[0042] 1, a film thickness adjustment mechanism 135 may be arranged around the rotor 120 with a predetermined gap therebetween, so as to sandwich the rotor 120, and adjust the film thickness of the liquid plasma raw material 101 by scraping off any liquid plasma raw material 101 that has not flowed into the gap. The film thickness adjustment mechanism 135 is located upstream of irradiation position I in the rotation direction of the rotor 120, and determines the film thickness of the liquid plasma raw material 101 at irradiation position I.
[0043] [About the Rotating Unit Configuration] The plasma generation mechanism 106 includes a rotor unit that houses the rotor 120. As shown in Fig. 2, the rotor unit 150 includes the rotor 120, a cover member 161, a heating unit 162, and a raw material supply unit 163, and the rotor 120 is housed in the cover member 161. Note that the cover member 161, the heating unit 162, and the raw material supply unit 163 are not shown in Fig. 1.
[0044] The cover member 161 houses the rotor 120 to prevent scattering of debris, and also forms the storage tank 133. The liquid plasma raw material 101 is stored in the vertically lower portion of the cover member 161, and the vertically lower portion of the cover member 161 constitutes the storage tank 133.
[0045] The heating unit 162 heats the liquid plasma raw material 101. The heating unit 162 is placed vertically below the cover member 161, i.e., on the outer periphery of the reservoir 133, and heats the liquid plasma raw material 101 via the cover member 161. The heating unit 162 may also be placed inside the reservoir 133 and heat the liquid plasma raw material 101 directly.
[0046] The raw material supply unit 163 supplies the liquid plasma raw material 101 to the storage tank 133. As shown in Fig. 2, the raw material supply unit 163 has a raw material introduction path 171, a raw material inlet 172, and a raw material supply port 173. In Fig. 2, the movement of the solid plasma raw material 141 is indicated by white arrows.
[0047] 2, the raw material inlet path 171 is a passage through which the solid plasma raw material 141 passes, and is cylindrical. The solid plasma raw material 141 is a plasma raw material in a solid phase, and when the solid plasma raw material 141 melts, it becomes the liquid plasma raw material 101. The solid plasma raw material 141 is a metal or alloy in a solid phase. There are no particular limitations on the shape of the solid plasma raw material 141, but it may be, for example, spherical.
[0048] As shown in Fig. 2, raw material inlet path 171 extends from the outside of cover member 161 toward storage tank 133 and is a passage through which solid plasma raw material 141 can pass. As shown in Fig. 2, raw material inlet path 171 is formed by an outer peripheral member 174 that surrounds the periphery in a tubular shape. Hereinafter, the end of raw material inlet path 171 on the storage tank 133 side will be referred to as storage tank side end 171a. A stopper 175 that closes raw material inlet path 171 and keeps solid plasma raw material 141 inside raw material inlet path 171 is provided at storage tank side end 171a. Stopper 175 may be made of the same material as outer peripheral member 174, or may be made of a different material.
[0049] As shown in FIG. 2, if the extension direction of raw material introduction path 171 is defined as extension direction D, extension direction D includes a component C that is directed vertically downward, and solid plasma raw material 141 is configured to move toward storage tank 133 by gravity.
[0050] The raw material inlet 172 is provided near the end of the raw material introduction path 171 opposite the storage tank 133, and is an opening through which the solid plasma raw material 141 is introduced. The raw material inlet 172 may be any opening that allows the solid plasma raw material 141 to pass through.
[0051] Raw material supply inlet 173 is provided in raw material introduction path 171, and is an opening through which liquid plasma raw material 101 passes. Raw material supply inlet 173 is provided vertically below raw material introduction path 171, at the storage tank side end 171a of raw material introduction path 171, and can be an opening provided in stopper 175 as shown in Figure 2. Raw material supply inlet 173 is configured so that solid plasma raw material 141 cannot pass through, but liquid plasma raw material 101 can.
[0052] Specifically, raw material supply port 173 has a shape and size that does not allow the passage of solid plasma raw material 141. As shown in Figure 2, if the minimum width of solid plasma raw material 141 is width W1 and the maximum width of raw material supply port 173 is width W2, width W2 is smaller than width W1.
[0053] 2 shows the case where the solid plasma raw material 141 is spherical and the raw material supply port 173 is circular, in which case the width W2 which is the diameter of the raw material supply port 173 is smaller than the width W1 which is the diameter of the solid plasma raw material 141. Similarly, width W2 is smaller than width W1 when the solid plasma raw material 141 and raw material supply port 173 have other shapes. There may be any other shape for raw material supply port 173 as long as it does not allow the solid plasma raw material 141 to pass through but allows the liquid plasma raw material 101 to pass through.
[0054] The raw material supply unit 163 has the above-mentioned configuration. The raw material supply unit 163 is configured so that the vicinity of the storage tank side end 171a is heated by the heating unit 162. Specifically, when the heating unit 162 generates heat, the stopper 175 and the peripheral member 174 in the vicinity thereof are heated by thermal conduction via the liquid plasma raw material 101 stored in the storage tank 133 and the cover member 161. Alternatively, a heating unit separate from the heating unit 162 may be provided in the vicinity of the storage tank side end 171a to directly heat the storage tank side end 171a.
[0055] Fig. 3 is a schematic diagram showing the introduction of plasma raw material by the raw material supply unit 163. As shown in Fig. 2, when solid plasma raw material 141 is charged into raw material inlet 172, the solid plasma raw material 141 moves within raw material introduction path 171 due to gravity and stops when it comes into contact with stopper 175. Because stopper 175 and outer peripheral member 174 at the storage tank side end 171a are heated by heating unit 162, as shown in Fig. 3, the solid plasma raw material 141 within raw material introduction path 171 melts little by little, generating liquid plasma raw material 101. The generated liquid plasma raw material 101 passes through raw material supply port 173 and flows into storage tank 133.
[0056] In the plasma generation mechanism 106, the liquid plasma raw material 101 is supplied to the storage tank 133 in the manner described above. The solid plasma raw material 141 passes through the raw material inlet path 171 while remaining solid, and melts at the storage tank end 171a, so it is only necessary to heat the storage tank end 171a, and the energy required for heating can be reduced. For example, when the solid plasma raw material 141 is tin, the melting point of tin is 232°C, so a large amount of energy would be required to heat the entire supply path above its melting point, but the plasma generation mechanism 106 makes it possible to reduce this amount of energy.
[0057] In addition, since molten metals such as tin are corrosive, it is necessary to use a corrosion-resistant coating or corrosion-resistant material in the supply path. In the plasma generation mechanism 106, the liquid plasma raw material 101 passes only near the raw material supply port 173, so the corrosion-resistant coating or material is required in only a few places, which reduces manufacturing costs.
[0058] Furthermore, when supplying molten metal to a storage tank, a valve is required to supply the molten metal at the appropriate timing. This valve must be an expensive valve that can withstand the high temperature of the molten metal, and even if an expensive valve is used, its lifespan is limited. On the other hand, in the plasma generation mechanism 106, the solid plasma raw material 141 can be simply fed into the raw material inlet 172 at any time, and no valve is required, making it possible to reduce manufacturing and maintenance costs.
[0059] 3, height H is the height of the bottom end of the solid plasma raw material 141 located at the storage tank side end 171a of the raw material supply unit 163. The raw material supply unit 163 is configured so that the liquid level 101a stored in the storage tank 133 does not exceed height H, in other words, so that the height at which the liquid level 101a contacts only the bottom end of the solid plasma raw material 141 is the upper limit of the height of the liquid level 101a.
[0060] When the liquid level 101a exceeds height H and the solid plasma raw material 141 is immersed in the liquid plasma raw material 101, the liquid plasma raw material 101 is cooled by contact with the solid plasma raw material 141, and the energy required to keep the liquid plasma raw material 101 molten increases.
[0061] Therefore, by configuring the raw material supply unit 163 so that the liquid level 101a does not exceed height H, it is possible to prevent the solid plasma raw material 141 from cooling the liquid plasma raw material 101 and to prevent destabilization of the output of radiation R. It is not a problem if the liquid level 101a is less than height H, that is, if the solid plasma raw material 141 is separated from the liquid level 101a.
[0062] 4 and 5 are schematic diagrams showing a specific configuration of the raw material supply section 163, where FIG. 4 is a cross-sectional view of the rotator unit 150 viewed vertically from above, and FIG. 5 is a cross-sectional view taken along the line AA in FIG. 4. As shown in the figures, the raw material supply section 163 is provided on the rear side of the rotating surface 120a of the cover member 161 that houses the rotator 120, and the raw material introduction passage 171 can be a hole formed in the cover member 161. In this case, the outer peripheral member 174 shown in FIG. 2 and the like corresponds to the cover member 161. Alternatively, the raw material introduction passage 171 may be formed by inserting the tubular outer peripheral member 174 into a hole provided in the cover member 161.
[0063] [Various configurations of the raw material supply section] A description will now be given of various components of the raw material supply unit 163. FIG.
[0064] Raw material supply port 173 may be composed of multiple small holes. There are no particular limitations on the shape of the holes, and raw material supply port 173 may be in the form of a louver or mesh opening. In addition, raw material supply port 173 may be any type that does not allow solid plasma raw material 141 to pass through but allows liquid plasma raw material 101 to pass through.
[0065] The position of the raw material supply port 173 is not limited to above the stopper 175. As shown in FIG. 6, the raw material supply port 173 may be formed between the stopper 175 and the outer peripheral member 174. As shown in the figure, the stopper 175 does not completely close the storage tank side end 171a of the outer peripheral member 174, and a gap serving as the raw material supply port 173 can be formed between the outer peripheral member 174 on the vertically lower side. Moreover, the stopper 175 is disposed slightly away from the outer peripheral member 174, and a gap serving as the raw material supply port 173 can be formed between the stopper 175 and the outer peripheral member 174. Furthermore, the raw material supply port 173 may be provided on the vertically lower side of the outer peripheral member 174.
[0066] The shape of the raw material inlet 171 is not limited to a straight line, and may be curved or bent. In addition, the raw material inlet 171 may have any shape that allows the solid plasma raw material 141 introduced into the raw material inlet 172 to be transported by gravity to the vicinity of the raw material supply port 173.
[0067] Furthermore, the raw material supply unit 163 does not necessarily have to be equipped with the stopper 175. The raw material introduction path 171 can also be shaped so that the diameter gradually decreases near the storage tank side end 171a towards said end. The solid plasma raw material 141 fed from the raw material inlet 172 stops upon contact with the outer peripheral member 174, and the generated liquid plasma raw material 101 flows into the storage tank 133 from the raw material supply port 173.
[0068] Alternatively, raw material introduction path 171 may be bent vertically upward near storage tank side end 171a. Solid plasma raw material 141 fed from raw material inlet 172 stops at the bottom of raw material introduction path 171 due to gravity, and the generated liquid plasma raw material 101 flows into storage tank 133 from raw material supply port 173.
[0069] Furthermore, raw material supply unit 163 may be provided with a vacuum exhaust port. The vacuum exhaust port is an opening provided in raw material introduction path 171, connects raw material introduction path 171 to a vacuum exhaust path (not shown), and is used to evacuate raw material introduction path 171. By evacuating raw material introduction path 171 via the vacuum exhaust port, the pressure difference between inside cover member 161 (see FIG. 2) and raw material introduction path 171 is eliminated, and midway stoppage of solid plasma raw material 141 due to the pressure difference can be prevented. The vacuum exhaust port may be provided anywhere in raw material introduction path 171. Furthermore, raw material supply port 173 may have any of the above configurations.
[0070] [About this disclosure] It is also possible to combine at least two of the characteristic parts of the present technology described above. In addition, the various effects described above are merely examples and are not limiting, and other effects may be achieved. [Explanation of symbols]
[0071] 100...Light source device 101...Liquid plasma raw material 106...Plasma generation mechanism 108...Beam source 120...rotating body 131...Rotational drive source 132…Shaft 133…Storage tank 141...Solid plasma raw material 150...Rotating unit 161...Cover member 162...Heating section 163...Raw material supply department 171...Raw material introduction path 172...Raw material input port 173…Raw material supply port 174...Outer periphery 175…Stopper
Claims
1. A plasma generation mechanism provided in a light source device that converts a liquid plasma raw material, which is a molten plasma raw material, into plasma by irradiating it with an energy beam to extract radiation, comprising: A rotor that rotates around a rotation axis; a rotation drive source that rotates the rotor around the rotation axis; a storage tank for storing the liquid plasma raw material, the rotor being partially immersed in the stored liquid plasma raw material; a heating unit for heating the liquid plasma raw material stored in the reservoir; a raw material supply section including a raw material inlet passage through which a solid plasma raw material, which is the plasma raw material in a solid state, passes, and a raw material supply port that is provided in the raw material inlet passage and through which the solid plasma raw material cannot pass but the liquid plasma raw material formed by melting the solid plasma raw material can pass, the liquid plasma raw material that has passed through the raw material supply port flowing into the reservoir; A plasma generation mechanism comprising:
2. 2. The plasma generation mechanism according to claim 1, The raw material supply port is configured so that the solid plasma raw material does not come into contact with the liquid surface of the liquid plasma raw material stored in the storage tank, or so that only the lower end of the solid plasma raw material comes into contact with the liquid surface. Plasma generation mechanism.
3. 2. The plasma generation mechanism according to claim 1, The maximum width of the raw material supply port is smaller than the minimum width of the solid plasma raw material. Plasma generation mechanism.
4. 2. The plasma generation mechanism according to claim 1, The heating section further heats and melts the solid plasma raw material located in the raw material introduction passage. Plasma generation mechanism.
5. 2. The plasma generation mechanism according to claim 1, The raw material supply unit includes an outer peripheral member that forms the outer periphery of the cylindrical raw material introduction passage, and a stopper that is provided at the end of the raw material introduction passage on the storage tank side and that stops the solid plasma raw material within the raw material introduction passage. Plasma generation mechanism.
6. The plasma generation mechanism according to claim 5, The heating section further heats and melts the solid plasma raw material held by the stopper. Plasma generation mechanism.
7. 2. The plasma generation mechanism according to claim 1, The rotating body has a rotation surface on which the energy beam is incident. Plasma generation mechanism.
8. The plasma generation mechanism according to claim 7, The raw material supply unit is provided on the rear side of the rotation surface of a cover member that houses the rotor and forms the storage tank. Plasma generation mechanism.
9. 2. The plasma generation mechanism according to claim 1, The radiation is extreme ultraviolet light or X-rays. Plasma generation mechanism.
10. The plasma generation mechanism according to claim 1 , The plasma raw material is tin, lithium, gadolinium, terbium, gallium, bismuth, indium, or an alloy containing at least one of these materials. Plasma generation mechanism.
11. A light source device that converts a liquid plasma raw material, which is a molten plasma raw material, into plasma by irradiating it with an energy beam and extracts radiation, a plasma generation mechanism comprising: a rotor that rotates about a rotation axis; a rotary drive source that rotates said rotor about said rotation axis; a storage tank that stores the liquid plasma raw material and in which a portion of said rotor is immersed in the stored liquid plasma raw material; a heating unit that heats the liquid plasma raw material stored in said storage tank; a raw material inlet path through which a solid plasma raw material that is the plasma raw material in a solid state passes; and a raw material supply unit that is provided in said raw material inlet path and has a raw material supply port through which the solid plasma raw material cannot pass but through which the liquid plasma raw material formed by melting the solid plasma raw material can pass, said liquid plasma raw material that has passed through the raw material supply port flows into said storage tank; a beam source for directing the energy beam at the surface of rotation; A light source device comprising:
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Extreme-ultraviolet light source device
JP2014216286A