LIGHT SOURCE DEVICE, INSPECTION DEVICE, EXPOSURE DEVICE, LIGHT SOURCE CONTROL METHOD, INSPECTION METHOD AND EXPOSURE METHOD

Abstract

A light source device (100) according to the present disclosure comprises an optical input system (120) containing a first optical element (OP1) configured to irradiate a target material (112) with excitation light (LR), an optical output system (130) containing a second optical element (OP2) configured to extract light (LO) generated by irradiating the target material (112) with the excitation light (LR), a target holding unit (110) configured to hold the target material (112), a detection unit (140) configured to detect a surface position of the target material (112), a drive unit (150) configured to effect a change in the position of a focusing point of at least one of the first optical element (OP1) and the second optical element (OP2), and a control unit (160) configured toto drive the drive unit (150) based on the surface position.

Description

BACKGROUND

[0001] The present disclosure relates to a light source device, an inspection device, an exposure device, a light source control method, an inspection method, and an exposure method.

[0002] Japanese Patent Application No. 2020-077007 describes a light source in which a target material is formed on the surface of a cylindrical member rotating about a rotation axis, and the formed target material is irradiated with excitation light to emit illumination light.

[0003] Japanese Patent Application No. 2022-168463 describes a light source in which a target material, which is molten metal, is held by centrifugal force on the inner wall of a crucible rotating about a rotation axis, and the held target material is irradiated with excitation light to emit illumination light. SUMMARY

[0004] In a light source device, the relative positions of a light-emitting point located near the surface of a target material and an optical element may fluctuate due to vibrations caused by the rotation of a target holding unit, such as a cylindrical element or a crucible, the deformation of a structure itself, and the consumption or addition of the target material to the target holding unit. Accordingly, light may not be stably extracted from the light source device.

[0005] An object of the present disclosure, which was made to solve such a problem, is to provide a light source device, an inspection device, an exposure device, a light source control method, an inspection method, and an exposure method that can improve the stability of the light extracted from the light source device.

[0006] A light source device according to the present disclosure comprises an input optical system including a first optical element configured to irradiate a target material with excitation light, an output optical system including a second optical element configured to extract light generated by irradiating the target material with the excitation light, a target holding unit configured to hold the target material, a detection unit configured to detect a surface position of the target material, a drive unit configured to cause a position of a focusing point of at least one of the first optical element and the second optical element to change, and a control unit configured to drive the drive unit based on the surface position.

[0007] In the light source device, the detection unit may detect the surface position as a relative position to the second optical element.

[0008] In the light source device, the first optical element may irradiate the target material with the excitation light at an angle inclined with respect to an axis perpendicular to a surface of the target material.

[0009] In the light source device, the target holding unit may move the target material to an irradiation position irradiated with the excitation light according to the movement of the target holding unit.

[0010] In the light source device, the detection unit may detect the surface position in a peripheral position other than the irradiation position and predict the surface position in the irradiation position from the detected surface position in the peripheral position, thereby detecting the surface position in the irradiation position.

[0011] In the light source device, the target material may comprise molten metal, and the target holding unit may comprise a container that accommodates the target material inside and supports the target material on an inner wall surface of the container with a centrifugal force.

[0012] In the light source device, the detection unit may detect the surface position of the target material based on the distance between a sensor and the surface of a liquid surface of the molten metal.

[0013] In the light source device, the detection unit may predict the surface position in the irradiation position from the surface position in a position near the irradiation position with respect to the moving direction of the target holding unit, and the control unit may control the drive unit based on the predicted surface position.

[0014] In the light source device, when the surface position changes in a predetermined period of time, the detection unit may predict the surface position based on the period of time, and the control unit may control the drive unit based on the predicted surface position.

[0015] In the light source device, the first optical element may include a mirror configured to reflect the excitation light onto the target material.

[0016] In the light source device, the second optical element may include a collector mirror configured to reflect the generated light.

[0017] In the light source device, the first optical element may include a mirror configured to reflect the excitation light onto the target material, the second optical element may include a collector mirror configured to reflect the generated light, and the control unit may set a drive control amount for the first optical element greater than a drive control amount for the second optical element.

[0018] In the light source device, the first optical element may include a condenser lens configured to condense the excitation light, and the control unit may control the drive unit to move the condenser lens in a direction parallel to an optical axis of the excitation light so that the position of the focusing point changes.

[0019] In the light source device, the first optical element may comprise a mirror configured to reflect the excitation light onto the target material and a condenser lens configured to condense the excitation light.When the surface position is a predetermined surface position, the control unit may control the drive unit to vary an optical axis of the mirror so that the position of the focusing point varies, and control the drive unit to move the condenser lens in a direction parallel to an optical axis of the excitation light so that the position of the focusing point varies, and, when the surface position is not the predetermined surface position, the control unit may control the drive unit to change the optical axis of the mirror so that the position of the focusing point varies, and limit the movement of the condenser lens in the direction parallel to the optical axis of the excitation light.

[0020] In the light source device, the light may contain EUV light.

[0021] An inspection apparatus according to the present disclosure includes: the above-explained light source device; and an inspection optical system configured to inspect an inspection target with the light extracted by the output optical system.

[0022] In the inspection device, the control unit can control the drive unit so that the light scans a field of view in the inspection target.

[0023] In the inspection device, the control unit may control the drive unit so that the movement of the scanning in a component of a short lateral direction of the field of view area having a rectangular shape in the inspection target remains within a fixed range.

[0024] An exposure apparatus according to the present disclosure includes: the above-explained light source device; and an exposure optical system configured to expose an exposure target with the light extracted from the output optical system.

[0025] In the exposure device, the control unit may control the drive unit so that the light scans an exposure area in the exposure target.

[0026] A light source control method according to the present disclosure includes: a step of holding a target material with a target holding unit; a step of detecting a surface position of the target material with a detecting unit; a step of a control unit that allows a drive unit to change a position of a focusing point of at least one of a first optical element and a second optical element based on the surface position; a step of causing an input optical system including the first optical element to irradiate the target material with excitation light; and a step of extracting, with an output optical system including the second optical element, light generated by irradiating the target material with the excitation light.

[0027] An inspection method according to the present disclosure includes a step of inspecting an inspection target with the light extracted by the above-explained light source control method.

[0028] An exposure method according to the present disclosure includes a step of exposing an exposure target with the light extracted by the above-explained light source control method.

[0029] According to the present disclosure, it is possible to provide a light source device, an inspection device, an exposure device, a light source control method, an inspection method, and an exposure method that can improve the stability of the light extracted from the light source device.

[0030] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a sectional view showing a light source device according to a first embodiment; Fig. 2 is a perspective view showing a container serving as a target holding unit in the light source device according to the first embodiment; Fig. 3 is a plan view showing the light source device according to the first embodiment; Fig. 4 is a diagram showing a detection unit, a drive unit, and a control unit in the light source device according to the first embodiment; Fig. 5 is a schematic diagram illustrating a relationship between the displacement of a surface position of a target material and the movement of a bright spot in the light source device according to the first embodiment, and is a diagram viewed from the direction of the rotation axis of a container; Fig. 6 is a schematic diagram illustrating a relationship between the displacement of the surface position of the target material and the movement of the bright spot in the light source device according to the first embodiment, and is a diagram viewed from a direction orthogonal to the rotation axis; Fig. 7 is a schematic diagram of a field of view range detected by a detector of an inspection device that detects light generated in the light source device according to the first embodiment; Fig. 8 is a schematic diagram illustrating cancellation of displacement of a surface position using a mirror in the light source device according to the first embodiment, and is a diagram viewed from the direction of the rotation axis of the container; Fig. 9 is a schematic diagram for illustrating the cancellation of the displacement of the surface position by means of the mirror in the light source device according to the first embodiment, and is a diagram viewed from the direction orthogonal to the rotation axis; Fig. 10 is a schematic diagram of a field of view range detected by the detector of the inspection apparatus that detects the light generated in the light source device according to the first embodiment; Fig. 11 is a flowchart showing a light source control method using the light source device according to the first embodiment; and Fig. 12 is a configuration diagram showing an inspection apparatus including the light source device according to the first embodiment. DESCRIPTION OF THE EMBODIMENTS

[0031] A specific configuration of an embodiment will be explained below with reference to the drawings. The following explanation shows a preferred embodiment of the present disclosure. The scope of the present disclosure is not limited to the embodiment explained below. In the following explanation, the same numerals and characters denote substantially the same content. (First embodiment)

[0032] A light source device according to a first embodiment will be explained. The light source device in the present embodiment generates light such as illumination light and exposure light, which is used for an optical device such as an inspection device and an exposure device. The light source device may be integrated with the optical device or disposed near the optical device as a separate body separated from the optical device. When the optical device is the inspection device, the light source device generates illumination light to illuminate an inspection target in the inspection device. When the optical device is the exposure device, the light source device generates exposure light to expose an exposure target in the exposure device.

[0033] The light source device generates light such as illumination light and exposure light by irradiating a target material held by a target holding unit with excitation light. In the following explanation, a light source device that sets molten metal held by a container as the target material is explained as an example of the light source device. Note that the light source device is not limited to the light source device that sets the molten metal in the container as the target material, but may also be a light source device that sets droplet-shaped liquid metal, solid material attached to a cylindrical drum, or the like as the target material.

[0034] Fig. 1 is a sectional view showing a light source device 100 according to the first embodiment. Fig. 2 is a perspective view showing a container 111 serving as a target holding unit 110 in the light source device 100 according to the first embodiment. Fig. 3 is a plan view showing the light source device 100 according to the first embodiment. In Fig. 3 several elements are omitted. As in the Fig. 1 to 3, the light source device 100 comprises a target holding unit 110, an input optical system 120, an output optical system 130, a detection unit 140, a sensor 141, a drive unit 150 and a control unit 160. In Fig. In Figure 1, the drive unit 150 is connected to a mirror 121, a condenser lens 122, and a collector mirror 131. However, the drive unit 150 does not always need to be connected to all of these optical elements. The control unit 160 is only connected to a few elements to avoid overcomplicating the figure. However, the control unit 160 can also be connected to other elements.

[0035] The target holding unit 110 contains a target material 112. The target holding unit 110 includes a container 111, e.g., a crucible. The container 111 can melt metal inside. The container 111 contains the target material 112, e.g., molten metal, which generates a plasma 127 when irradiated with excitation light LR. The excitation light LR is, e.g., laser light including IR (infrared) light.

[0036] Note that the target holding unit 110 is not limited to the container 111 and may also be a cylindrical barrel. In this case, the target holding unit 110 holds the target material 112 by fixing a solid material that becomes the target material 112, such as xenon (Xe) frozen on the surface of the barrel.

[0037] The target material 112 may contain molten metal. Note that the target material 112 is not limited to the molten metal in the container 111, but may also be solid metal, droplets, or the like if the target material 112 is a substance that generates the plasma 127 when irradiated with the excitation light LR. The molten metal is, for example, molten tin (Sn) or lithium (Li), but is not limited to tin and lithium if the molten metal generates the plasma 127 when irradiated with the excitation light LR.

[0038] The container 111 has a rotation axis R and rotates centered around the rotation axis R. The container 111 has, for example, a cylindrical shape with a closed opening. A closed part of the container 111 is called a bottom 113. A cylindrical part of the container 111 is called a cylindrical portion 114. The surface on the inside of the bottom 113 is called a bottom surface 115. The surface on the inside of the cylindrical portion 114 is called an inner wall surface 116. A groove 117 may be formed in a connecting portion between the bottom 113 and the cylindrical portion 114. It should be noted that the container 111 may have a shape other than the above if the container 111 can accommodate the molten metal.

[0039] The target holding unit 110 supports the target material 112 against the inner wall surface 116 of the container 111 with centrifugal force. The inner wall surface 116, which is shaped to surround the rotation axis R, may comprise a cylindrical portion with a constant distance from the rotation axis R or a conical (or mortar-shaped, hereinafter referred to as mortar-shaped) portion that widens upward toward the outside. For example, the mortar-shaped part of the inner wall surface 116 may be connected to the groove 117.

[0040] In addition to the target holding unit 110, the light source device 100 may also include a heater 118 and a debris shield 119. The target material 112, e.g., molten metal, may be formed in the container 111 by heating the heater 118. The debris shield 119 is arranged in an opening 111a of the container 111 to cover the target material 112.

[0041] The target material 112 also rotates about the rotation axis R according to the rotation of the container 111 about the rotation axis R. As in Fig. 3, for example, the target material 112, which is located at a position P1 facing the sensor 141 at time t1, moves to an irradiation position PS at time t2 according to the rotation of the container 111. In this way, the target holding unit 110 moves the target material 112 according to the movement (ie, the rotational movement) of the target holding unit 110 to the irradiation position PS, where the target material 112 is irradiated with the excitation light LR.

[0042] The input optical system 120 includes a first optical element OP1. The first optical element OP1 irradiates the target material 112 with the excitation light LR. The first optical element OP1 includes, for example, at least one of a mirror 121 and a condenser lens 122. When the first optical element OP1 is an optical element that irradiates the target material 112 with the excitation light LR, the first optical element OP1 is not limited to the mirror 121 and the condenser lens 122, but may also be any type of optical element, including a laser LS that generates the excitation light LR.

[0043] The first optical element OP1 irradiates the target material 112 with the excitation light LR at an angle inclined with respect to an axis perpendicular to the surface of the target material 112. Specifically, for example, the first optical element OP1 irradiates the surface of the irradiation position PS with the excitation light LR at an inclined angle of incidence. By irradiating the surface of the irradiation position PS with the excitation light LR at such an inclined angle, the influence of debris on the optical element including the collector mirror 131 can be suppressed. One reason why the influence of dirt on the optical element, such as a collector mirror 131, can be suppressed will be explained below.

[0044] When the surface of the target material 112 is irradiated with the excitation light LR from a direction orthogonal to the surface of the target material 112, the debris scatters in all directions, concentrating on the direction orthogonal to the surface. In this case, the debris is likely to adhere to the collector mirror 131 facing the irradiation position PS. On the other hand, when the surface of the irradiation position PS is irradiated with the excitation light LR at an oblique angle, the debris may be scattered in a reflection direction on the side opposite to an incident direction of the excitation light LR. In this way, the adhesion of the debris to the collector mirror 131 can be prevented. In addition, the excitation light LR is irradiated at an incident angle inclined to the near side of the irradiation position PS relative to the moving direction of the target holding unit 110.That is, the excitation light LR is irradiated from a direction having a component of an incident angle inclined from the near side in a plane orthogonal to the rotation axis R. Then, an angular velocity is applied in a rotation direction of the container 111 in a direction in which the debris scatters. Therefore, it is possible to further scatter the debris in a reflection direction of the excitation light LR. In this way, it is possible to suppress the influence of the debris on the optical elements such as the collector mirror 131.

[0045] The mirror 121 reflects, for example, the excitation light LR generated by the laser LS to the irradiation position PS of the target material 112. The mirror 121 can be a mirror, such as a piezo-steering mirror. Note that the mirror 121 is not limited to the piezo-steering mirror and can also include a galvano mirror, a polygon mirror, or the like, if the mirror 121 can reflect the excitation light LR onto the target material 112. The condenser lens 122 focuses the excitation light LR at the irradiation position PS of the target material 112.

[0046] The light source device 100 may include the laser LS that generates the excitation light LR. On the other hand, the light source device 100 may introduce the excitation light LR of the laser LS, which is installed separately from the light source device 100 on the outside of the light source device 100, into the light source device 100. The excitation light LR is, for example, laser light including IR light. The excitation light LR may irradiate the target material 112 depending on whether it is controlled by the control unit 160 or not. For example, the excitation light LR is reflected by the mirror 121 and converged by the condenser lens 122. Accordingly, the excitation light LR irradiates the target material 112.

[0047] The output optical system 130 includes a second optical element OP2. The second optical element OP2 extracts, from the light source device 100, the light L0 generated by irradiating the target material 112 with the excitation light LR. The second optical element OP2 includes, for example, the collector mirror 131. Note that when the second optical element OP2 is an optical element that extracts the light L0 generated by irradiating the target material 112 with the excitation light LR, the second optical element OP2 is not limited to the collector mirror 131 and may also be any optical element, including a second collector mirror (not shown) that further reflects the light L0 reflected by the collector mirror 131.

[0048] The collector mirror 131 reflects the light L0 generated by the target material 112 upon irradiation with the excitation light LR. The collector mirror 131 reflects, for example, EUV light LE generated by the irradiation of the excitation light LR. That is, the light L0 may include the EUV light LE. The EUV light LE is generated from the plasma 127 created by irradiating the target material 112 with the excitation light LR. The EUV light LE, which originates from the plasma 127 generated by the target material 112, is emitted as illumination light to an optical device, e.g., an inspection device. The illumination light thus includes the EUV light generated by the plasma 127.

[0049] The detection unit 140 detects a surface position of the target material 112. The detection unit 140 is connected to the sensor 141 and detects, from the sensor 141, a surface position of the target material 112 measured by the sensor 141. The detection unit 140 detects a surface position of the target material 112 in the irradiation position PS where the excitation light LR irradiates the target material 112. The detection unit 140 can detect a surface position measured by the sensor 141 in the irradiation position PS or, as explained below, predict a surface position in the irradiation position PS from a surface position measured by the sensor 141 in a peripheral position. The detection unit 140 can predict the surface position of the target material 112 by taking into account an inclination with respect to the rotation axis and a vibration of the target holding unit 110.

[0050] The detection unit 140 can be a separate body from the sensor 141 or integrated into the sensor 141. The sensor 141 can include, for example, a displacement sensor, a high-speed camera, a low-speed camera, a quadrature PD (photodiode) camera, and a TDI (time-delay integration) camera. The detection unit 140 can combine other sensors with the sensor 141, such as the displacement sensor, to detect the surface position of the target material 112. Accordingly, the other sensors can supplement the phase information that the sensor 141, such as the displacement sensor, cannot easily detect.

[0051] The detection unit 140 can detect the surface position of the target material 112 as a relative position to the second optical element OP2. Specifically, the detection unit 140 can detect the surface position in the irradiation position PS of the target material 112 as a relative position to the second optical element OP2, or the surface position in the peripheral position as a relative position to the second optical element OP2. The detection unit 140 can detect the surface position of the target material 112 based on the distance between the sensor 141 and the surface of a molten metal. The detection unit 140 can detect the surface position of the target material 112 based on the thickness of the liquid surface of the molten metal from the inner wall surface 116.When the target material 112 is a solid material attached to a cylindrical drum, the detection unit 140 may detect the surface position of the target material 112 based on an inclination and a vibration amount of the drum and the thickness of the surface of the solid material from the upper surface (the top surface) of the drum.

[0052] The detection unit 140 can detect a surface position at a peripheral position other than the irradiation position PS. The peripheral position includes a region other than the irradiation position PS on the inner wall surface 116 of the container 111. The detection unit 140 can predict the surface position of the irradiation position PS from the surface position at the peripheral position detected by the sensor 141. Specifically, the detection unit 140 predicts the surface position at the irradiation position PS from a surface position at a position near the irradiation position PS with respect to the moving direction of the target holding unit 110.At this time, by considering the moving speed (rotation speed) of the target holding unit 110 and the distance between the irradiation position PS and the peripheral position, the surface position at the irradiation position PS at a time (an irradiation time) when the excitation light reaches the irradiation position PS can be predicted. The detection unit 140 thus predicts the surface position at the irradiation position PS to detect the surface position at the irradiation position PS.

[0053] If the sensor 141 is arranged in a position facing the irradiation position PS in order to be able to measure and detect the surface position at the irradiation position PS, the sensor 141 is likely to be affected by debris. Since the plasma 127 is generated at the irradiation position PS, the sensor 141 is likely to fail to accurately detect the surface position. Therefore, the sensor 141 is arranged to be in a peripheral position separated from the irradiation position PS. This can suppress the influence of debris and improve the measurement accuracy of the surface position. For example, the sensor 141 may be arranged to face a position P1 on the side opposite the irradiation position PS with respect to the rotation axis R.Note that the sensor 141 may be arranged to face a peripheral position other than the position P1 and to face the irradiation position PS if the influence of the debris can be reduced.

[0054] Fig. Fig. 4 is a diagram showing the detection unit 140, the drive unit 150, and the control unit 160 in the light source device 100 according to the first embodiment. As explained above, the position of the sensor 141 is not limited to the position opposite the irradiation position PS, but may also be a position opposite the peripheral position, for example, the position P1. As shown in Fig. As shown in Figure 4, the drive unit 150 causes the position of the focusing point of at least one of the two optical elements OP1 and OP2 to change. The drive unit 150 is, for example, an actuator.

[0055] The drive unit 150 drives the first optical element OP1 to change the irradiation direction of the excitation light LR. For example, if the first optical element OP1 is the mirror 121, the drive unit 150 pivots the angle of the mirror 121 with respect to the excitation light LR to perform beam scanning. Specifically, the drive unit 150 changes a reflection surface of the mirror 121 so that the excitation light LR scans the surface of the target material 112 in a predetermined direction.

[0056] If the mirror 121 is a piezo-steering mirror, the drive unit 150 may comprise a drive mechanism provided in the piezo-steering mirror. If the mirror 121 is a galvano mirror, a polygon mirror, or the like, the drive unit 150 may be a drive mechanism provided in the galvano mirror, polygon mirror, or the like.

[0057] If another actuator with short lead time and good controllability is available, the drive unit 150 can be the actuator.

[0058] The plasma 127 is generated in the irradiation position PS, where the excitation light LR irradiates the target material 112. The generated plasma 127 is observed as a bright spot. The drive unit 150 causes a change in the optical axis of the mirror 121 to change the position of the focusing point. Accordingly, the drive unit 150 moves the bright spot at high speed to shave the beam. When the optical device is an inspection device, it is thus possible to improve the uniformity and availability on a detector of the inspection device. By changing the optical axis of the mirror 121, the drive unit 150 can cause the position of the focusing point to vary in at least two axial directions on the surface of the target material 112 in the irradiation position PS.

[0059] Fig. 5 is a schematic diagram illustrating a relationship between the displacement of the surface position of the target material 112 and the movement of the bright spot in the light source device 100 according to the first embodiment, and is a diagram viewed from the direction of the rotation axis R of the container 111. Fig. 6 is a schematic diagram illustrating the relationship between the displacement of the surface position of the target material 112 and the movement of the bright spot in the light source device 100 according to the first embodiment, and is a diagram viewed from a direction orthogonal to the rotation axis R. Fig. 7 is a schematic diagram illustrating a field of view (FOV) detected by the detector of the inspection device that detects the generated light L0 in the light source device 100 according to the first embodiment. Note that, here, the displacement of a surface position of the target material 112 held by the container 111 is explained as an example. However, the same applies when considering a surface position of the target material 112 held by a cylindrical drum surface.

[0060] As in Fig. 7, for ease of explanation, one direction in the field of view detected by the detector is represented as the X-axis direction, and another direction orthogonal to the one direction is represented as the Y-axis direction. In this case, the Z-axis direction is a defocus direction of a light spot BS. The defocus direction corresponds to the optical axis direction of the collector mirror 131. Fig. 5 and Fig. 6 shows a relationship between a moving direction in the field of view area FOV of the light spot BS of the light L0 generated from a bright spot of the plasma 127 and a moving direction of the plasma 127 generated in the target material 112.

[0061] The displacement of the surface position of the target material 112 includes surface vibrations caused by vibrations due to the rotation of the container 111 and the like, which propagate to the surface position, and displacements due to the consumption or supply of the target material 112. When the target material 112 is a solid such as frozen xenon, the displacement of the surface position of the target material 112 includes displacement due to the roughness and unevenness of the target surface.

[0062] When the excitation light LR is incident obliquely on the surface position of the target material 112 and the surface position is shifted, the light spot BS moves in directions having components of the X-axis direction and the Y-axis direction in the field of view area FOV, as shown in the Fig. 5 to 7. In this way, the displacement of the bright spot in the direction orthogonal to the optical axis of the collector mirror 131 is a displacement in the X-axis and Y-axis directions of the light spot BS on the field of view area FOV.

[0063] Fig. 8 is a schematic diagram illustrating the cancellation of the displacement of a surface position using the mirror 121 in the light source device 100 according to the first embodiment, and is a diagram viewed from the direction of the rotation axis R of the container 111. Fig. Fig. 9 is a schematic diagram illustrating the cancellation of the displacement of the surface position using the mirror 121 in the light source device 100 according to the first embodiment, and is a diagram viewed from a direction orthogonal to the rotation axis R. As shown in Figs. Fig. 8 and Fig. As illustrated in Figure 9, the displacement of a component perpendicular to an optical axis of the mirror 121 can be canceled by causing the reflection surface of the mirror 121, such as a steering mirror, to change according to the displacement of the surface position. With the displacement of the surface position, the surface vibration is displaced at a high frequency. Therefore, the steering mirror that can be driven at a high frequency is suitable for canceling the surface vibration. The direction of the displacement of the surface position due to the consumption and supply of the target material 112 is the same as the direction of the surface vibration explained above. However, this displacement due to the consumption and supply of the target material 112 is a low-frequency displacement. Thus, the drive unit 150 drives the first optical element OP1 at a low frequency.

[0064] Fig. 10 is a schematic diagram of the field of view (FOV) detected by the detector of the inspection device that detects the light generated in the light source device 100 according to the first embodiment. As shown in Fig. As shown in Figure 10, the displacement of a bright spot in a direction parallel to an optical axis is a defocusing in the Z-axis direction of the light spot BS. Therefore, the drive unit 150 moves the position of the condenser lens 122 in a direction parallel to the optical axis of the excitation light LR. Accordingly, the drive unit 150 causes the position of the focusing point of the excitation light LR to vary. As explained above, when the first optical element OP1 includes the condenser lens 122, the drive unit 150 moves the position of the condenser lens 122 in a direction parallel to the optical axis of the excitation light LR.

[0065] The drive unit 150 can drive the second optical element OP2 to change an extraction direction of the generated light L0 and / or a focus position of the target holding unit 110. When the surface position of the target material 112 is shifted, an optical path of the light L0 generated by the target material 112 is shifted. Therefore, when the second optical element OP2 includes the collector mirror 131, the drive unit 150 pivots an angle of the collector mirror 131 with respect to the bright light spot L0.

[0066] The control unit 160 controls the drive unit 150 based on the surface position of the target material 112 detected by the detection unit 140. The detection unit 140 detects the surface position of the target material 112 as a relative position to the second optical element OP2. If the surface position detected as a relative position to the second optical element OP2 is predicted to shift by a predetermined threshold value or more, the control unit 160 controls the drive unit 150 so that the position of the focusing point of at least one of the first optical element OP1 or the second optical element OP2 changes.Therefore, the control unit 160 can limit the execution of the control of the drive unit 150 even if the surface position (the thickness of the target material 112 from the inner wall surface 116 and the drum surface) is shifted if the relative position is not shifted by the predetermined threshold or more.

[0067] The control unit 160 calculates a control amount based on the surface position detected by the detection unit 140. The control unit 160 then controls the drive unit 150 based on the calculated control amount. The control unit 160 may include, for example, a control board. For example, the control unit 160 controls the drive unit 150 based on the calculated control amount so that the optical axis of the mirror 121 and the position of the focusing point change. The control unit 160 controls the drive unit 150 based on the calculated control amount so that the condenser lens 122 is moved parallel to the optical axis of the excitation light LR and the position of the focusing point varies.Further, the control unit 160 controls the drive unit 150 based on the calculated control amount so that the optical axis of the collector mirror 131 and the optical axis of the generated light L0 change. The control unit 160 can control the drive unit 150 so that the light L0 scans the field of view area FOV in the inspection target of the inspection device.

[0068] For example, the control unit 160 controls the drive unit 150 so that during the movement of the scanning in the Fig. For example, for the Y-axis direction component shown in Figure 7, 80% of a trace of the center point of the light spot BS must remain within the field of view (FOV). A control amount serving as a driving target can be set in advance based on an experimental result or a simulation result. Specifically, an experiment or simulation is conducted on how much the light spot BS moves in the Y-axis direction according to how much the surface position is shifted, and how much the light spot BS moves in the Y-axis direction according to how much the optical element is driven. Note that the 80% described above is an example. 80% of the light spot BS itself is allowed to remain within the field of view (FOV).In this way, the control unit 160 controls the drive unit 150 so that the movement of the scanning in a short lateral direction component of the field of view FOV, which has a rectangular shape in the inspection target, remains within a specified range.

[0069] The control unit 160 may prioritize the control of the first optical element OP1 over the control of the second optical element OP2. For example, the control unit 160 may set a control amount for the first optical element OP1 greater than a control amount for the second optical element OP2. The control unit 160 may set the number of control operations for the first optical element OP1 greater than the number of control operations for the second optical element OP2. This is because the first optical element OP1 is easier to control than the second optical element OP2 and has less impact on the other optical elements after being set in motion by the drive unit 150.

[0070] The surface position of the target material 112 may suddenly increase or decrease. The surface position fluctuates suddenly, for example, when the target material 112 is supplied to the container and when the target material 112 is a so-called "backflow" (the evaporated or scattered target is supplied to the container 111 again). In this case, the surface position increases or decreases so much that, in addition to changing the mirror 121, defocusing measures by the condenser lens 122 are required. Therefore, in the event of such a sudden fluctuation, the surface position is set in advance as a predetermined surface position.When the surface position of the target material 112 is the predetermined surface position, the control unit 160 controls the drive unit 150 to move the optical axis of the mirror 121 so that the position of the focusing point varies, and controls the drive unit 150 to move the condenser lens 122 in the direction parallel to the optical axis of the excitation light LR so that the position of the focusing point varies.

[0071] When the detection unit 140 predicts a surface position at the irradiation position PS from a surface position at the position P1 on the near side of the irradiation position PS with respect to the moving direction of the target holding unit 110, the control unit 160 calculates a control amount based on the predicted surface position. The control unit 160 controls the drive unit 150 forward based on the calculated control amount.

[0072] The sensor 141 can measure a surface position at the irradiation position PS, and the control unit 160 can control the drive unit 150 based on the measured surface position. However, it is conceivable that the transmission of a control signal from the control unit 160 to the drive unit 150 or the calculation of a control amount may not be timely enough to control the position of the focusing point of the optical element to match the irradiation timing of the excitation light LR. Therefore, the control unit 160 controls the drive unit 150 based on the surface position at the irradiation position PS predicted from the surface position at position P1 (e.g., by feedforward control). To enable such operation, the drive unit 150 can be designed to operate at several hundred hertz.

[0073] When the surface position changes within a predetermined period, the detection unit 140 can predict a surface position of the target material 112 based on the period, and the control unit 160 can control the drive unit 150 based on the predicted surface position (e.g., by driving forward). The control unit 160 can calculate a control amount based on the period and control the drive unit 150 forward. For example, when the fluctuation in the surface position includes a surface vibration that oscillates at a predetermined period, the control unit 160 calculates a period of the surface vibration. The control unit 160 calculates a control amount based on the calculated period and controls the drive unit 150 forward. <lichtquellensteuerungsverfahren>

[0074] Next, a light source control method using the light source device 100 will be explained. Fig. 11 is a flowchart showing a light source control method using the light source device 100 according to the first embodiment. As in step S11 in Fig. 11, the light source device 100 first holds the target material 112 with the target holding unit 110. The light source device (100) contains, for example, in a container (111), e.g., a crucible, the target material (112), e.g., molten metal, which generates the plasma (127) when irradiated with the excitation light (LR).

[0075] Subsequently, the light source device 100 detects the surface position of the target material 112 with the detection unit 140, as shown in step S12. For example, the detection unit 140 may predict a surface position at the irradiation position PS from the surface position at the peripheral position measured by the sensor 141, thereby detecting the surface position at the irradiation position PS.

[0076] Subsequently, as shown in step S13, the control unit 160 enables the drive unit 150 to change the position of the focusing point of at least one of the first optical element OP1 and the second optical element OP2 based on the surface position detected by the detection unit 140. The light source device 100 causes the control unit 160 to calculate a control amount for driving the first optical element OP1 and / or the second optical element OP2. Specifically, the light source device 100 causes the control unit 160 to calculate a control amount for the drive unit 150 to drive the first optical element OP1 and / or the second optical element OP2 based on the surface position detected by the detection unit 140.Then, the control unit 160 allows the drive unit 150 to change the position of the focusing point of at least one of the two optical elements OP1 and OP2. For example, if the first optical element OP1 includes the mirror 121, the control unit 160 controls the drive unit 150 to change the optical path of the mirror 121, so that the position of the focusing point changes. If the first optical element OP1 includes the condenser lens 122, the control unit 160 controls the drive unit 150 to move the condenser lens 122 parallel to the optical axis of the excitation light LR, so that the position of the focusing point changes.When the second optical element OP2 includes the collector mirror 131, the control unit 160 controls the drive unit 150 based on the calculated control amount to change the optical axis of the collector mirror 131 so as to change the optical axis of the generated light L0 and / or to change its focusing point on the target holding unit 110.

[0077] Subsequently, as shown in step S14, the light source device 100 uses the input optical system 120 including the first optical element OP1 to irradiate the target material 112 with the excitation light LR.

[0078] Subsequently, as shown in step S15, the light source device 100 extracts the light L0 generated by irradiating the target material 112 with the excitation light LR using the output optical system 130 including the second optical element OP2. By controlling the light source device 100 as described above, it is possible to extract the light L0 used for the optical device. <Optische Vorrichtung

[0079] The optical device is explained below. The optical device is explained using an inspection device as an example.

[0080] Fig. 12 is a configuration diagram showing an inspection apparatus 1 including the light source device 100 according to the first embodiment. As shown in Fig. As shown in FIG. 12, the inspection apparatus 1 includes an illumination optical system 200, an inspection optical system 300, a detector 410, and an image processing unit 420. Note that the inspection apparatus 1 may also include the light source device 100. The inspection apparatus 1 is a device that inspects a defect or the like of a sample 500, using the light L0 generated by the light source device 100 as the illumination light L1. The sample 500 is, for example, an EUV mask. Note that the sample 500 is not limited to the EUV mask and may also be a semiconductor substrate or the like.

[0081] The illumination optical system 200 includes an ellipsoidal mirror 210, an ellipsoidal mirror 220, and a plug-in mirror 230. The inspection optical system 300 includes a concave mirror with a hole 310, a convex mirror 320, a flat mirror 330, and a concave mirror 340. The concave mirror with a hole 310 and the convex mirror 320 form a Schwarzschild magnification optical system.

[0082] The light source device 100 generates illumination light L1. The illumination light L1 includes, for example, EUV light LE having a wavelength of 13.5 nm, which corresponds to the exposure wavelength of the EUV mask for the sample 500. Note that the illumination light L1 may also include light other than EUV light. The illumination light L1 generated by the light source device 100 is reflected by the ellipsoidal mirror 210. The illumination light L1 reflected by the ellipsoidal mirror 210 travels further while being narrowed and is converged at a convergence point IF1. Thus, the ellipsoidal mirror 210 reflects the illumination light L1 generated by the light source device 100 as converging light. The convergence point IF1 is a position that coincides with a top surface 510 of the sample 500, for example, a surface of the sample 500. B. the EUV mask, and a detection surface 411 of the detector 410.

[0083] After passing the convergence point IF1, the illumination light L1 spreads out and strikes a reflection mirror such as the ellipsoidal mirror 220. This causes the illumination light L1 reflected by the ellipsoidal mirror 210 to be incident on the ellipsoidal mirror 220 via the convergence point IF1 as divergent light. The illumination light L1 incident on the ellipsoidal mirror 220 is reflected by the ellipsoidal mirror 220, travels further while narrowing, and is incident on the incident mirror 230. That is, the ellipsoidal mirror 220 reflects the incident illumination light L1 as convergent light. The ellipsoidal mirror 220 allows the illumination light L1 to be incident on the incident mirror 230. The incident mirror 230 is arranged directly above the EUV mask. The illumination light L1 falls on the incident mirror 230 and is reflected by the sample 500.The incident mirror 230 thus causes the illumination light L1 to be incident on the sample 500 by reflecting the illumination light L1 reflected by the ellipsoidal mirror 220 back onto the sample 500.

[0084] The ellipsoidal mirror 220 focuses the illumination light L1 onto the sample 500. The illumination optical system 200 is mounted to create an image of the bright spot of the light source device 100 on the upper surface 510 of the sample 500 when the illumination light L1 illuminates the sample 500. Thus, the illumination optical system 200 provides critical illumination. As explained above, the illumination optical system 200 illuminates the sample 500, e.g., the EUV mask, using critical illumination by the illumination light L1 generated by the light source device 100.

[0085] The sample 500 is arranged on a stage 520. Here, a plane parallel to the top surface 510 of the sample 500 is represented as the αβ-plane, and a direction perpendicular to the αβ-plane is represented as the γ-axis direction. The illuminating light L1 is directed onto the sample 500 from a direction deviating from the γ-axis. That is, the illuminating light L1 is incident obliquely and illuminates the sample 500.

[0086] The stage 520 is a three-dimensional drive stage with a drive unit 530. The drive unit 530 can illuminate a desired area of ​​the sample 500 by moving the stage 520 in the αβ plane. Furthermore, the drive unit 530 can perform focus adjustment by moving the stage 520 in the y-axis direction.

[0087] The illuminating light L1 of the light source device 100 illuminates an inspection area of ​​the sample 500. The inspection area illuminated by the illuminating light L1 is, for example, a 0.5 mm square. Note that the inspection area is not limited to the 0.5 mm square. The illuminating light L1 is incident on the sample 500 from a direction inclined with respect to the y-axis. The light from the sample 500 illuminated by the illuminating light L1 is incident on the concave mirror with the hole 310. In the following explanation, the light from the sample 500 illuminated by the illuminating light L1 is referred to as reflected light L2. Note that the light incident from the sample 500 onto the concave mirror with the hole 310 is not limited to reflected light L2, but may also include diffracted light or the like. The light L2 reflected from the sample 500 is incident on the concave mirror with the hole 310.In the center of the concave mirror with hole 310 there is a hole 311. The concave mirror with hole 310 focuses the light L2 reflected from the sample 500 and reflects the focused reflected light L2 as convergent light.

[0088] The light L2 reflected by the concave mirror with hole 310 is projected onto the concave mirror 320. The convex mirror 320 reflects the light L12 reflected by the concave mirror with hole 310 toward the hole 311 of the concave mirror with hole 310. The reflected light L2, which has passed through the hole 311, is incident on the plane mirror 330. The plane mirror 330 allows the light L2 reflected by the convex mirror 320 to enter as convergent light through the hole 311 of the concave mirror with hole 310. The light L2 incident on the plane mirror 330 is reflected by the plane mirror 330. The light L2 reflected by the plane mirror 330 travels under constriction and is bundled at a convergence point IF2. Thus, the plane mirror 330 reflects the incident reflected light L2 as convergent light. The convergence point IF2 can be called an aperture stop.The convergence point IF2 is a position conjugated with the upper surface 510 of the sample 500 and the detection surface 411 of the detector 410.

[0089] After passing the convergence point IF2, the reflected light L2 propagates and strikes the concave mirror 340. Thus, the light L2 reflected by the plane mirror 330 as convergent light is incident on the concave mirror 340 via the focusing point IF2 as divergent light. The concave mirror 340 reflects the incident reflected light L2 as convergent light to the detector 410. The light L2 reflected by the concave mirror 340 is detected by the detector 410. As explained above, the optical inspection system 300 inspects the sample 500, which is the inspection target, with the light L1 extracted from the output optical system 130 of the light source device 100. That is, the optical inspection system 300 condenses the light L2 reflected from the sample 500 illuminated by the illumination light L1 and guides the condensed reflected light L2 to the detector 410.

[0090] The detector 410 may include a TDI (Time Delay Integration) sensor. The detector 410 receives light from the sample 500 illuminated by the illumination light L1. An area on the sample 500 detected by the detector 410 is referred to as the field of view region 511. The detector 410 receives the reflected light L2 from the field of view region 511 illuminated by the illumination light L1. The field of view region 511 may be included in the inspection area illuminated by the illumination light L1. The detector 410 acquires image data of the sample 500, e.g., the EUV mask. If the detector 410 includes a TDI sensor, the detector 410 includes a plurality of imaging elements arranged linearly adjacent to one another in one direction. The imaging elements are, for example, CCDs (Charge Coupled Devices). Note that the imaging elements are not limited to CCDs.

[0091] The image data of the sample 500 acquired by the detector 410 is output to the image processing unit 420 and processed in the image processing unit 420. The image processing unit 420 may be, for example, a server device or an information processing device such as a personal computer.

[0092] The reflected light L2 contains information about a defect or the like of the sample 500. Regularly reflected light of the illumination light L1, which is incident on the sample 500 from a direction inclined with respect to the Z-axis, is detected by the inspection optical system 300. If a defect is present in the sample 500, it is displayed as a dark image. Such an observation method is called bright-field observation. Note that the inspection device 1 makes the illumination light L1 incident on the sample 500 from the Z-axis direction, causing the inspection optical system 300 to detect the illumination light L1. If a defect is present in the sample 500, it is displayed as a bright image. Such an observation method is called dark-field observation.

[0093] As explained above, the inspection apparatus 1 in the present embodiment includes the above-explained light source device 100 and the inspection optical system 300 that inspects an inspection target with the light L0 extracted from the output optical system 130. An inspection method using the inspection apparatus 1 includes a step of inspecting the inspection target with the light L0 obtained by the above-explained light source control method. Note that the inspection apparatus 1 is explained as an optical device. However, the optical device may also be an exposure device. For example, the exposure device includes the above-explained light source device 100 and an exposure optical system that exposes an exposure target with the light L0 extracted from the output optical system 130.The control unit 160 can control the drive unit 150 so that the light L0 scans an exposure area in the exposure target. An exposure method using the exposure device includes a step of exposing the exposure target to the light L0 extracted by the light source control method explained above.

[0094] The effects of the present embodiment will be explained below. In the present embodiment, the light source device 100 drives the drive unit 150 with a control amount that depends on the surface position of the target material 112. Accordingly, the light source device 100 causes the position of the focusing point of the first optical element OP1 and / or the second optical element OP2 to change. Therefore, even if the surface position of the target material 112 fluctuates due to vibration and consumption of the target material 112, it is possible to improve the stability of the light L0 extracted from the light source device 100 because the focusing point is varied due to the fluctuation.

[0095] For example, the first optical element OP1, such as the mirror 121, may be initially introduced to improve uniformity and availability on the detector 410 of the inspection device 1. Specifically, the mirror 121 of the first optical element OP1 scans the illumination light L1 to uniformly illuminate the field of view area FOV. In the present embodiment, such a first optical element OP1 is also used to cancel the bright spot shift caused by the surface position shift. In the present embodiment, since it is possible to appropriately cope with fluctuations in the bright spot position due to the surface position shift in the irradiation position PS caused by the thickness variation of the target material 112, it is possible to realize stabilization of the intensity of the generated light L1, such as the EUV light LE.

[0096] The detection unit 140 detects the surface position of the target material 112 as a relative position to the second optical element OP2. This improves the accuracy of the surface position. The detection unit 140 detects a surface position at a peripheral position other than the irradiation position PS and predicts a surface position at the irradiation position PS from the detected surface position at the peripheral position. Specifically, the detection unit 140 predicts a surface position at the irradiation position PS from a surface position at a position on the near side of the irradiation position PS with respect to the moving direction of the target holding unit 110. Since the focusing point of the excitation light LR can be adjusted to the surface position at the irradiation position, it is possible to improve the stability of the light L1.In addition, the control unit 160 calculates a control amount based on the predicted surface position and controls the drive unit 150 forward. This makes it possible to change the focus point depending on the shift in the surface position.

[0097] The target holding unit 110 supports the target material 112 against the inner wall surface 116 through the centrifugal force of the rotating container 111. This allows the surface position of the target material 112 to be uniformed and the stability of the light L1 to be improved.

[0098] The control unit 160 can change the optical axis of the mirror 121 to change the position of the focusing point, or it can move the condenser lens 122 in a direction parallel to the optical axis of the excitation light LR to change the position of the focusing point. The control unit 160 can change the optical axis of the collector mirror 131 to change the optical axis of the generated light L0 and / or to vary the position of the focusing point relative to the target holding unit 110. Since the control amount is calculated in this way depending on the fluctuation in the surface position, the stability of the light L0 can be improved.

[0099] Note: The detection unit 140 may detect a reference position of the surface position of the target material 112. Here, the reference position of the surface position of the target material 112 may be a surface position of the target material 112 at a time when the target material 112 was last irradiated with the excitation light LR, or a surface position predetermined when the optical device was installed or activated. The reference position may be a position determined by another method. The control unit 160 controls the drive unit 150 based on the surface position of the target material 112 detected by the detection unit 140. At this time, the detection unit 140 may determine that the surface position of the target material 112 is shifted from the reference position.When the detection unit detects that the deviation of the surface position from the reference position exceeds a predetermined threshold, the control unit 160 controls the drive unit 150 so that the position of the focusing point of the first optical element OP1 and / or the second optical element OP2 changes.For example, if it is determined that the deviation of the surface position from the reference position exceeds a predetermined threshold, the control unit controls the drive unit to change the optical axis of the mirror so that the position of the focusing point changes, and the drive unit to move the condenser lens in a direction parallel to an optical axis of the excitation light so that the position of the focusing point changes, and if it is not determined that the displacement of the surface position from the reference position exceeds a predetermined threshold, the control unit controls the drive unit to change the optical axis of the mirror so that the position of the focusing point varies, and limits the movement of the condenser lens in the direction parallel to the optical axis of the excitation light.

[0100] The detection unit 140 can detect the surface position of the target material 112 as a relative position to at least one of the first optical element OP1 and the second optical element OP2 (simply referred to as the target optical element). Specifically, the detection unit 140 can detect the surface position in the irradiation position PS of the target material 112 as a relative position to the target optical element, or detect the surface position in the peripheral position as a relative position to the target optical element. The position sensor 141 can be attached to the target optical element or to the drive unit 150. Therefore, the position of the position sensor can change in conjunction with the drive of the target optical element.

[0101] The control unit 160 can drive the drive unit 150 based on the surface position of the target material 112 detected by the detection unit 140. The detection unit 140 detects the surface position of the target material 112 as a relative position to the optical element of the target. If the surface position detected as a relative position to the optical element of the target is predicted to shift by a predetermined threshold or more, the control unit 160 controls the drive unit 150 to change the position of the focusing point of at least one of the first optical element OP1 or the second optical element OP2.Therefore, the control unit 160 can limit the execution of the control of the drive unit 150 even if the surface position (the thickness of the target material 112 from the inner wall surface 116 and the drum surface) is shifted if the relative position is not shifted by the predetermined threshold or more.

[0102] The embodiment of the present disclosure has been explained above. However, the present disclosure includes appropriate changes that do not impair the purpose and advantages of the present disclosure, and is not limited by the above-explained embodiment. In the embodiment of the present disclosure, the target holding unit 110 is the container 111, such as the crucible. However, the target holding unit 110 is not limited thereto and may be a target holding unit that holds the target material 112 on the surface of a cylindrical object, a target holding unit that holds the target material 112 with a belt-like object, or the like. The constituent elements of the first embodiment can be arbitrarily combined.

[0103] From the disclosure thus described, it will be apparent that the embodiments of the disclosure may be varied in many respects. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2020-077007

[0002] US 2022-168463

[0003] < / lichtquellensteuerungsverfahren>

Claims

[1] A light source device comprising: an input optical system having a first optical element configured to irradiate a target material with excitation light; an output optical system having a second optical element configured to extract light generated by irradiating the target material with the excitation light; a target holding unit configured to hold the target material; a detection unit configured to detect a surface position of the target material; a drive unit configured to cause a change in the position of a focusing point of at least one of the first optical element and the second optical element; and a control unit configured to drive the drive unit based on the surface position. [2] The light source device according to claim 1, wherein the detecting unit detects the surface position as a relative position to the second optical element. [3] The light source device according to claim 1, wherein the first optical element irradiates the target material with the excitation light at an angle inclined with respect to an axis perpendicular to a surface of the target material. [4] The light source device according to claim 1, wherein the target holding unit moves the target material to an irradiation position irradiated by the excitation light according to the movement of the target holding unit. [5] The light source device according to claim 4, wherein the detecting unit detects the surface position in a peripheral position other than the irradiation position and predicts the surface position in the irradiation position from the detected surface position in the peripheral position, thereby detecting the surface position in the irradiation position. [6] A light source device according to claim 4, wherein the target material contains molten metal, and the target holding unit comprises a container that accommodates the target material inside and supports the target material on an inner wall surface of the container with a centrifugal force. [7] The light source device according to claim 6, wherein the detecting unit detects the surface position of the target material based on a distance from a sensor to a surface of a liquid surface of the molten metal. [8] A light source device according to claim 5, wherein the detection unit predicts the surface position in the irradiation position from the surface position in a position on a near side of the irradiation position with respect to a direction of movement of the target holding unit, and the control unit controls the drive unit based on the predicted surface position. [9] The light source device according to claim 1, wherein, when the surface position varies with a predetermined period, the detection unit predicts the surface position based on the period, and the control unit controls the drive unit based on the predicted surface position. [10] The light source device according to claim 1, wherein the first optical element includes a mirror configured to reflect the excitation light onto the target material. [11] The light source device according to claim 1, wherein the second optical element includes a collector mirror configured to reflect the generated light. [12] A light source device according to claim 1, wherein the first optical element contains a mirror which is arranged to reflect the excitation light onto the target material, the second optical element includes a collector mirror configured to reflect the generated light, and the control unit sets a drive control amount for the first optical element greater than a drive control amount for the second optical element. [13] A light source device according to claim 1, wherein the first optical element contains a condenser lens which is arranged to focus the excitation light, and the control unit controls the drive unit to move the condenser lens in a direction parallel to an optical axis of the excitation light so that the position of the focusing point changes. [14] A light source device according to claim 1, wherein the first optical element includes a mirror configured to reflect the excitation light onto the target material and a condenser lens configured to focus the excitation light, when the surface position is a predetermined surface position, the control unit controls the drive unit to cause an optical axis of the mirror to change so that the position of the focusing point changes, and controls the drive unit to move the condenser lens in a direction parallel to an optical axis of the excitation light so that the position of the focusing point changes, and When the surface position is not the predetermined surface position, the control unit controls the drive unit to cause the optical axis of the mirror to change, so that the position of the focusing point changes and limits the movement of the condenser lens in the direction parallel to the optical axis of the excitation light. [15] The light source device according to claim 1, wherein the light includes EUV light. [16] Inspection device comprising: the light source device according to any one of claims 1 to 15; and an optical inspection system configured to inspect an inspection target with the light extracted by the output optical system. [17] The inspection device according to claim 16, wherein the control unit drives the drive unit so that the light scans a field of view in the inspection target. [18] The inspection apparatus according to claim 16, wherein the control unit controls the drive unit so that the movement of the scanning in a component of a short lateral direction of the field of view area having a rectangular shape in the inspection target remains within a fixed range. [19] Exposure device comprising: the light source device according to any one of claims 1 to 15; and an exposure optical system configured to expose an exposure target with the light extracted by the output optical system. [20] The exposure apparatus according to claim 19, wherein the control unit drives the drive unit so that the light scans an exposure area in the exposure target. [21] A light source control method comprising: a step of holding a target material with a target holding unit; a step of detecting a surface position of the target material with a detecting unit; a step of allowing, by a control unit, based on the surface position, a drive unit to cause the position of a focusing point of at least a first optical element and a second optical element to change; a step of causing an input optical system including the first optical element to irradiate the target material with excitation light; and a step of extracting light generated by irradiating the target material with the excitation light with an output optical system including the second optical element. [22] An inspection method comprising a step of inspecting an inspection target with the light extracted by the light source control method according to claim 21. [23] An exposure method comprising a step of exposing an exposure target to the light extracted by the light source control method according to claim 21.

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