Supply device, supply method and light source

Abstract

To provide a supplying apparatus capable of stably generating illuminating light such as EUV light, a supplying method, and a light source.SOLUTION: A supplying apparatus 1 includes: a container 10 having an inner peripheral surface 14a surrounding a rotational axis R1, in which a molten target 50 is held by the inner peripheral surface 14a by centrifugal force when rotating the container 10 holding the molten target 50 obtained by melting a target member 51 around the rotational axis R1; a supplying unit 20 for supplying the target member 51 to the molten target 50; a monitoring part 30 for monitoring a position on the inner peripheral surface 14a of the molten target 50 generating plasma by irradiation of laser beams; and a control part 40 for controlling a supplying amount of the target member 51 on the basis of the position monitored by the monitoring part 30.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a supply device, a supply method and a light source, for example for generating EUV light. [Background technology]

[0002] Methods for continuous target supply in high-brightness EUV light sources include using droplets, depositing a thin target film on a transparent substrate and irradiating the substrate with a laser to blow the target off, and dropping a solid ball into a molten target pool. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-001924 A [Patent Document 2] Patent Publication No. 2021-043361 Summary of the Invention [Problem to be solved by the invention]

[0004] In the method using droplets or thin films, it is difficult to control the target behavior during flight, and the problem is that the equipment becomes complicated. In addition, the method of dropping a solid target ball into the target molten pool causes a temperature drop and incomplete melting of the molten pool, which in turn causes flow path stacks due to target solidification. For these reasons, there are problems with the stability, reliability, and maintainability of the light source.

[0005] In addition, in an LPP (Laser Produced Plasma) light source, which uses centrifugal force from a rotor to form a molten target film on the vessel wall, the target is scattered as debris as light is emitted and reduced, causing the target film thickness to change over time. As a result, if the laser focus position is fixed, a misalignment occurs between the laser focus and the target surface. This causes a problem of a decrease in the amount of EUV light generated.

[0006] The object of the present invention is to solve such problems, and to provide a supply device, a supply method, and a light source that can stably generate illumination light such as EUV light. [Means for solving the problem]

[0007] The supply device of the present invention includes a container having an inner surface surrounding a rotation axis, wherein when the container holding a molten target in the form of a melted target material is rotated around the rotation axis, the molten target is held on the inner surface by centrifugal force, a supply unit that supplies the target material to the molten target, a monitoring unit that monitors the position on the inner surface of the molten target in which plasma is generated by irradiating it with laser light, and a control unit that controls the amount of the target material supplied based on the position monitored by the monitoring unit.

[0008] In the supply device, the supply unit may supply the target member in a linear shape.

[0009] Furthermore, in the above supply device, the supply unit may have a plate heated to a temperature equal to or higher than the melting point of the target material, and the target material may be melted by contacting the plate with the target material, thereby supplying the molten target into the container.

[0010] In the above-described supply device, the inner circumferential surface may have a groove formed along the inner circumference, and the molten target may be held in the groove.

[0011] In the above supply device, the inner circumferential surface may have a groove formed along the inner circumference, the molten target may be held in the groove, the plate may be cylindrical with the rotation axis as a central axis, and the outer circumferential surface of the plate may cover the groove.

[0012] The supply method of the present invention includes the steps of: rotating a container having an inner circumferential surface surrounding a rotation axis, the container holding a molten target formed by melting a target member, about the rotation axis, and holding the molten target on the inner circumferential surface by centrifugal force; supplying the target member to the molten target; monitoring the position on the inner circumferential surface of the molten target, in which plasma has been generated by irradiating it with laser light; and controlling the supply amount of the target member based on the monitored position.

[0013] In the supplying method, the step of supplying the target member may include supplying the target member in a linear shape.

[0014] Furthermore, in the above supply method, in the step of supplying the target material, the target material may be melted by contacting it with a plate heated to a temperature equal to or higher than the melting point of the target material, and the molten target may be supplied into the container.

[0015] In the above supply method, in the step of holding the molten target on the inner circumferential surface, the inner circumferential surface may have a groove formed along an inner circumference, and the molten target may be held in the groove.

[0016] In addition, in the above-described supply method, in the step of holding the molten target on the inner circumferential surface, the inner circumferential surface may have a groove formed along an inner circumference, and in the step of holding the molten target in the groove and supplying the target member, the plate may be cylindrical with the rotation axis as a central axis, and the groove may be covered by the outer circumferential surface of the plate.

[0017] The light source according to the present invention includes the above-mentioned supply device, a laser light source that irradiates the molten target with the laser light, and an optical member that extracts the EUV light generated from the plasma. Effect of the Invention

[0018] According to the present invention, it is possible to provide a supply device, a supply method, and a light source capable of stably generating illumination light such as EUV light. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a configuration diagram illustrating a supply device according to the first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view illustrating a container according to the first embodiment. [Diagram 3] FIG. 2 is a perspective view illustrating a supply unit according to the first embodiment. [Figure 4] FIG. 2 is a perspective view illustrating a plate according to the first embodiment. [Diagram 5] FIG. 11 is a perspective view illustrating a plate according to another example of the first embodiment. [Figure 6] 10 is a cross-sectional view illustrating a plate according to another example of the first embodiment. FIG. [Figure 7] FIG. 2 is a flow chart illustrating a supply method according to the first embodiment. [Figure 8] FIG. 11 is a configuration diagram illustrating a light source according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The specific configuration of this embodiment will be described below with reference to the drawings. The following description shows a preferred embodiment of the present invention, and the scope of the present invention is not limited to the following embodiment. In the following description, parts with the same reference numerals indicate substantially the same contents.

[0021] (Embodiment 1) A supplying device and a supplying method according to the first embodiment will be described. The supplying device and the supplying method of the present embodiment supply a target member to a container holding a molten target. First, the <supplying device> will be described. Then, the <supplying method> will be described.

[0022] <Feeding device> Fig. 1 is a configuration diagram illustrating a supply device according to embodiment 1. As shown in Fig. 1, the supply device 1 includes a container 10, a supply unit 20, a monitoring section 30, and a control section 40. Fig. 1 shows a part of the configuration in a cross-sectional view.

[0023] The vessel 10 holds a molten target 50. The vessel 10 is, for example, a crucible, and metal can be melted inside. The vessel 10 contains a material that does not easily react with the molten target 50, such as aluminum nitride (AlN), silicon carbide (SiC), graphite (C), etc.

[0024] The molten target 50 generates plasma by irradiation with a laser beam. The molten target 50 is a melted target member 51. The target member 51 is, for example, a material containing at least one of indium tin (InSn), tin (Sn), indium (In), lithium (Li), gallium (Ga), etc., or an alloy containing these materials. Note that the target member 51 is not limited to the above-mentioned materials as long as the melted molten target 50 generates plasma by irradiation with a laser beam. The container 10 is disposed in the chamber CH. The inside of the chamber CH may be depressurized to, for example, a vacuum, or may be filled with a predetermined gas.

[0025] The container 10 has a rotation axis R1 and rotates around the rotation axis R1. For example, a rod-shaped shaft 11 that extends coaxially with the rotation axis R1 is connected to the container 10. When the shaft 11 rotates around the rotation axis R1, a rotational force is transmitted to the container 10. Therefore, the container 10 rotates around the rotation axis R1.

[0026] The shaft 11 is connected to the rotary motor 12. The rotary motor 12 transmits power to the shaft 11 to rotate about a rotation axis R1. As a result, the rotary motor 12 rotates the container 10 about the rotation axis R1 via the shaft 11.

[0027] The container 10 has, for example, a cylindrical shape with one opening closed. The closed part of the container 10 is called the bottom 13. The cylindrical part of the container 10 is called the cylindrical part 14. The rotation axis R1 of the container 10 extends, for example, in the vertical direction. The bottom 13 is located at the bottom, and the open opening 15 is located at the top. The inner surface of the bottom 13 is called the bottom surface 13a. The outer surface of the bottom 13 is called the bottom surface 13b. The bottom surface 13b is the surface opposite to the bottom surface 13a. When the rotation axis R1 extends in the vertical direction and the opening 15 is located at the top, the bottom surface 13a faces upward, and the bottom surface 13b faces downward. The shaft 11 is connected to the bottom surface 13b of the bottom 13.

[0028] A heater 17 may be provided near the container 10. A molten target 50 can be formed in the container 10 by heating from the heater 17. The heater 17 is disposed below the bottom 13 of the container 10, for example.

[0029] The inner wall surface of the cylindrical portion 14 is called the inner peripheral surface 14a. The outer surface of the cylindrical portion 14 is called the outer peripheral surface 14b. The outer peripheral surface 14b is the surface opposite to the inner peripheral surface 14a. The inner peripheral surface 14a surrounds the rotation axis R1. Thus, the container 10 has the inner peripheral surface 14a surrounding the rotation axis R1. When the container 10 holding the molten target 50 is rotated around the rotation axis R1, the molten target 50 is held on the inner peripheral surface 14a by centrifugal force. For example, the molten target 50 sticks to the inner peripheral surface 14a by centrifugal force. As a result, the molten target 50 is disposed on the inner peripheral surface 14a.

[0030] Fig. 2 is a cross-sectional view illustrating the container 10 of the first embodiment. As shown in Fig. 2, the inner circumferential surface 14a formed to surround the rotation axis R1 may include a cylindrical portion whose distance from the rotation axis R1 is constant. The inner circumferential surface 14a may include an inclined surface whose distance from the rotation axis R1 changes. For example, the inner circumferential surface 14a may have a corner R at the connection portion with the bottom surface 13a.

[0031] Furthermore, the inner peripheral surface 14a of the container 10 may have a groove 16 formed along the inner circumference. The groove 16 is formed, for example, along the intersection line between the inner peripheral surface 14a and a plane perpendicular to the rotation axis R1. The groove 16 is recessed in the inner peripheral surface 14a in a direction away from the rotation axis R1.

[0032] When the inner circumferential surface 14a has a groove 16, the molten target 50 may be held in the groove 16. By holding the molten target 50 in the groove 16, the movement of the molten target 50 can be restricted, and disturbance of the liquid surface of the molten target 50 can be suppressed. In addition, since the amount of the molten target 50 can be restricted within the groove 16, the amount of the required target member 51 can be reduced. Note that a part of the molten target 50 may be located outside the groove 16.

[0033] FIG. 3 is a perspective view illustrating the supply unit 20 according to the first embodiment. As shown in FIG. 3, the supply unit 20 supplies a target member 51 to a molten target 50 held in a container 10. The target member 51 may be linear. The linear target member 51 may be wound around a bobbin 21 and held. The supply unit 20 supplies the linear target member 51 from the bobbin 21 to the molten target 50 in the container 10. For example, the delivery section 24 of the supply unit 20 delivers the linear target member 51 to the molten target 50 on the inner circumferential surface 14a. By supplying the linear target member 51, it is possible to continuously supply the target member 51. Therefore, it is not necessary to stop the supply device 1 in order to supply the target member 51 to the container 10.

[0034] FIG. 4 is a perspective view illustrating a plate according to the first embodiment. As shown in FIG. 4, the supply unit 20 may have a plate 22. The plate 22 is, for example, plate-shaped. The plate 22 is disposed in the container 10. The plate 22 is disposed, for example, facing the inner circumferential surface 14a. The plate 22 is at a temperature equal to or higher than the melting point of the target member 51. For example, the plate 22 may be at a temperature equal to or higher than the melting point of the target member 51 by a heating member such as a heater, or may be at a temperature equal to or higher than the melting point of the target member 51 by the radiant heat of the container 10 and the molten target 50 in the container 10.

[0035] The supply unit 20 may supply the molten target 50 into the container 10 by bringing the target member 51 into contact with the plate 22 to melt it. For example, the molten target 50 melted by the plate 22 falls onto the bottom surface 13a, and then reaches the inner circumferential surface 14a by centrifugal force. This eliminates the need to bring the target member 51 into contact with the molten target 50 in the container 10, thereby suppressing a decrease in temperature of the molten target 50. In addition, disturbance of the liquid surface of the molten target 50 due to vibration or the like can be suppressed.

[0036] FIG. 5 is a perspective view illustrating a plate according to another example of the first embodiment. FIG. 6 is a cross-sectional view illustrating a plate according to another example of the first embodiment. As shown in FIGS. 5 and 6, the plate 23 may be cylindrical with the rotation axis R1 as the central axis. The outer peripheral surface 23b of the plate 23 may cover the groove 16. This makes it possible to keep the molten target 50 warm and stabilize the state of the molten target 50. In addition, it is possible to suppress the scattering of debris when the plasma is generated by irradiating the laser light. Note that a part of the plate 23 may be removed for irradiating the laser light and extracting the generated EUV light.

[0037] 1 and 2, the monitoring unit 30 monitors the position of the molten target 50 on the inner circumferential surface 14a, where plasma has been generated by irradiation with laser light. The monitoring unit 30 is, for example, a displacement meter. The monitoring unit 30 is disposed facing the inner circumferential surface 14a. The monitoring unit 30 monitors the position of the molten target 50 located on the inner circumferential surface 14a. For example, the monitoring unit 30 monitors the position on the inner circumferential surface 14a by measuring the distance to the surface of the molten target 50 facing the rotation axis R1.

[0038] The control unit 40 acquires the position of the melt target 50 on the inner peripheral surface 14a monitored by the monitoring unit 30. The control unit 40 then controls the supply amount of the target member 51 based on the acquired position of the melt target 50 on the inner peripheral surface 14a. For example, when the amount of the melt target 50 decreases and the position of the melt target 50 on the inner peripheral surface 14a changes, the control unit 40 controls the supply amount of the target member 51 to be increased. On the other hand, when the amount of the melt target 50 is maintained at a predetermined amount and the position of the melt target 50 on the inner peripheral surface 14a does not change, the control unit 40 controls the supply amount of the target member 51 to be stopped. The control unit 40 is, for example, a personal computer, a microcomputer, or the like that performs information processing.

[0039] <Supply method> Next, a method of supplying the target members 51 will be described. Fig. 7 is a flow chart illustrating the supplying method according to the first embodiment.

[0040] As shown in step S11 of Fig. 7, the molten target 50 is held on the inner peripheral surface 14a by centrifugal force. Specifically, the container 10 has an inner peripheral surface 14a surrounding a rotation axis R1, and holds the molten target 50 formed by melting the target member 51. The container 10 is rotated about the rotation axis R1. In this manner, the molten target 50 is held on the inner peripheral surface 14a by centrifugal force. When the molten target 50 is held on the inner peripheral surface 14a, the inner peripheral surface 14a may have a groove 16 formed along the inner circumference. The molten target 50 may be held in the groove 16.

[0041] Next, as shown in step S12, target members 51 are supplied to the molten target 50. For example, when supplying the target members 51, the supply unit 20 is caused to supply linear target members 51. Alternatively, when supplying the target members 51, the supply unit 20 may cause the target members 51 to come into contact with the plate 22 heated to a temperature equal to or higher than the melting point of the target members 51, thereby melting the target members 51, and supply the molten target 50 into the container 10.

[0042] When the molten target 50 is held in the groove 16, the plate 23 may be cylindrical with the rotation axis R1 as the central axis. The groove 16 may be covered with the outer circumferential surface 23b of the plate 23.

[0043] Next, as shown in step S13, the position on the inner circumferential surface 14a of the molten target 50 is monitored. For example, the monitoring unit 30 is caused to monitor the position on the inner circumferential surface 14a of the molten target 50 where plasma has been generated by irradiation with laser light.

[0044] Next, as shown in step S14, the supply amount of the target members 51 is controlled based on the position on the inner circumferential surface 14a of the molten target 50 monitored by the monitoring unit 30. Specifically, the control unit 40 is caused to acquire the position on the inner circumferential surface 14a of the molten target 50 monitored by the monitoring unit 30, and is caused to control the supply amount of the target members 51 based on the acquired position. In this manner, the target members 51 are supplied.

[0045] Next, the effects of this embodiment will be described. In the supply device 1 and supply method for the target member 51 of this embodiment, the position of the molten target 50 in the container 10 is controlled to a constant position by a monitoring unit 30 such as a displacement meter. This makes it possible to keep the focal position of the laser light on the surface of the molten target 50 constant. Therefore, illumination light such as EUV light can be generated stably, and the amount of light can be stabilized.

[0046] Furthermore, by forming the target members 51 in a linear shape, the supply unit 20 including the bobbin 21 and the like can continuously supply the target members 51 to the container 10. This allows for continuous operation and improves productivity. Furthermore, maintenance can be made easier and the device can be simplified.

[0047] Furthermore, by using the linear target member 51 as a supply source, the surface position of the molten target 50 can be continuously stabilized, and changes in the amount of illumination light caused by a decrease in the molten target 50 due to debris scattering can be suppressed.

[0048] (Embodiment 2) Next, a light source according to a second embodiment will be described. The light source of this embodiment extracts illumination light using the supply device 1 described above. The illumination light is, for example, EUV light. The light source of this embodiment is, for example, a light source of illumination light that illuminates an inspection object in an inspection apparatus. The light source may also be used as a light source of exposure light in an exposure apparatus.

[0049] Fig. 8 is a configuration diagram illustrating a light source according to the second embodiment. As shown in Fig. 8, the light source 2 includes a supply device 1, a laser light source 60, and an optical member 70. The supply device 1 is similar to the supply device 1 in the first embodiment. Note that some of the components of the supply device 1 described in the first embodiment are omitted to avoid cluttering the drawing. Also, some of the components are shown in cross-section.

[0050] The laser light source 60 generates a laser beam. The laser light source 60 irradiates the generated laser beam onto the molten target 50. The laser light source 60 may irradiate the molten target 50 with the laser beam via an optical member such as a condenser lens. The molten target 50 generates plasma by being irradiated with the laser beam. When ions and electrons in the plasma recombine, EUV light is generated. In this manner, the molten target 50 is irradiated with the laser beam, and the EUV light is generated from the plasma.

[0051] The optical member 70 extracts the EUV light generated from the plasma. The optical member 70 is, for example, a mirror. The mirror may be a plane mirror or a concave mirror. The optical member 70 is disposed above the container 10 in which the molten target 50 is held. The optical member 70 reflects the generated EUV light. The EUV light reflected by the optical member 70 is extracted to the outside of the light source 2.

[0052] According to this embodiment, the light source 2 extracts EUV light from the molten target 50 to which the target member 51 is supplied by the supply device 1. Therefore, the light source 2 can stably generate EUV light as illumination light. Furthermore, the light source 2 can be operated continuously, and maintenance can be simplified. Other configurations and effects are included in the description of the first embodiment.

[0053] Although the embodiments of the present invention have been described above, the present invention includes appropriate modifications that do not impair the objects and advantages thereof, and is not limited to the above-mentioned embodiments. Furthermore, the configurations in the first and second embodiments may be appropriately combined. [Explanation of symbols]

[0054] 1 Feeding device 2 light source 10 containers 11 Shaft 12 Rotation Motor 13 Bottom 13a Bottom 13b Bottom side 14 Cylindrical section 14a Inner surface 14b Outer surface 15 Opening 16 groove 17 Heater 20 Supply Units 21 Bobbin 22, 23 Plate 23b Outer surface 24 Payout section 30 Monitoring Department 40 Control section 50 Molten Target 51 Target material 60 Laser Light Source 70 Optical Components CH Chamber R1 Rotation axis

Claims

1. a container having an inner circumferential surface surrounding a rotation axis, the container holding a molten target formed by melting a target member being rotated around the rotation axis, the molten target being held on the inner circumferential surface by centrifugal force; a supply unit for supplying the target member to the container; a monitoring unit that monitors a position of the molten target on the inner circumferential surface; a control unit that controls a supply amount of the target member when the position at which the amount of the molten target held in the container is reduced below a predetermined amount is acquired based on the position monitored by the monitoring unit; and Equipped with The supply unit supplies the linear target member. Feeding device.

2. The supply unit supplies the molten target into the container by feeding the linear target member to the inner circumferential surface.

2. The delivery device of claim 1.

3. the supply unit has a plate that is heated to a temperature equal to or higher than the melting point of the target material; Melting the target member by contacting it with the plate, and providing the molten target in the vessel.

2. The delivery device of claim 1.

4. a container having an inner circumferential surface surrounding a rotation axis, the container holding a molten target formed by melting a target member being rotated around the rotation axis, the molten target being held on the inner circumferential surface by centrifugal force; a supply unit for supplying the target member to the container; a monitoring unit that monitors a position of the molten target on the inner circumferential surface; a control unit that controls a supply amount of the target member when the position at which the amount of the molten target held in the container is reduced below a predetermined amount is acquired based on the position monitored by the monitoring unit; and Equipped with the supply unit has a plate that is heated to a temperature equal to or higher than the melting point of the target material; Melting the target member by contacting it with the plate, and providing the molten target in the vessel. Feeding device.

5. The inner circumferential surface has a groove formed along the inner periphery, The molten target is held in the groove. A supplying device according to any one of claims 1 to 4.

6. a container having an inner circumferential surface surrounding a rotation axis, the container holding a molten target formed by melting a target member being rotated around the rotation axis, the molten target being held on the inner circumferential surface by centrifugal force; a supply unit for supplying the target member to the container; a monitoring unit that monitors a position of the molten target on the inner circumferential surface; a control unit that controls a supply amount of the target member when the position at which the amount of the molten target held in the container is reduced below a predetermined amount is acquired based on the position monitored by the monitoring unit; and Equipped with The inner circumferential surface has a groove formed along the inner periphery, The molten target is held in the groove. Feeding device.

7. The inner circumferential surface has a groove formed along the inner periphery, The molten target is held in the groove; The plate has a cylindrical shape with the rotation shaft as a central axis, The outer circumferential surface of the plate covers the groove.

5. A supplying device according to claim 3 or 4.

8. a step of rotating a container having an inner circumferential surface surrounding a rotation axis, the container holding a molten target formed by melting a target member, around the rotation axis, and holding the molten target on the inner circumferential surface by centrifugal force; causing the container to provide the target material; monitoring a position of the molten target on the inner circumferential surface; a step of controlling a supply amount of the target member when the position at which the amount of the molten target held in the container is reduced below a predetermined amount is acquired based on the monitored position; Equipped with In the step of supplying the target member, Supplying the target member in a linear shape; Supply method.

9. In the step of supplying the target member, The linear target member is fed to the inner circumferential surface to supply the molten target into the container.

9. The method of claim 8.

10. In the step of supplying the target member, The target material is brought into contact with a plate heated to a melting point or higher of the target material to melt the target material, and the molten target is supplied into the container.

9. The method of claim 8.

11. a step of rotating a container having an inner circumferential surface surrounding a rotation axis, the container holding a molten target formed by melting a target member, around the rotation axis, and holding the molten target on the inner circumferential surface by centrifugal force; causing the container to provide the target material; monitoring a position of the molten target on the inner circumferential surface; a step of controlling a supply amount of the target member when the position at which the amount of the molten target held in the container is reduced below a predetermined amount is acquired based on the monitored position; Equipped with In the step of supplying the target member, The target material is brought into contact with a plate heated to a melting point or higher of the target material to melt the target material, and the molten target is supplied into the container. Supply method.

12. In the step of holding the molten target on the inner circumferential surface, The inner circumferential surface has a groove formed along the inner periphery, The molten target is held in the groove. The supply method according to any one of claims 8 to 11.

13. a step of rotating a container having an inner circumferential surface surrounding a rotation axis, the container holding a molten target formed by melting a target member, around the rotation axis, and holding the molten target on the inner circumferential surface by centrifugal force; causing the container to provide the target material; monitoring a position of the molten target on the inner circumferential surface; a step of controlling a supply amount of the target member when the position at which the amount of the molten target held in the container is reduced below a predetermined amount is acquired based on the monitored position; Equipped with In the step of holding the molten target on the inner circumferential surface, The inner circumferential surface has a groove formed along the inner periphery, The molten target is held in the groove. Supply method.

14. In the step of holding the molten target on the inner circumferential surface, The inner circumferential surface has a groove formed along the inner periphery, The molten target is held in the groove; In the step of supplying the target member, The plate has a cylindrical shape with the rotation shaft as a central axis, The groove is covered with an outer peripheral surface of the plate.

12. The method of claim 10 or 11.

15. A supply device according to any one of claims 1 to 7, a laser light source that irradiates the molten target with laser light; an optical member that extracts EUV light generated from the plasma generated by the irradiation of the laser light; A light source equipped with

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