Light source device, inspection device, exposure apparatus, light source control method, inspection method and exposure method

Abstract

To provide a light source device, an inspection device, an exposure apparatus, a light source control method, an inspection method and an exposure method which can improve stability of light taken out from a light source.SOLUTION: A light source device 100 according to the present disclosure comprises: an input optical system 120 including a first optical member OP which irradiates a target material 112 with excitation light LR; an output optical system 130 including a second optical member OP2 which takes out light L0 generated by irradiating the target material 112 with excitation light LR; a target holding part 110 which holds the target material 112; an acquisition part 145 which acquires a displacement of the surface position of the target material 112; a drive part 150 which fluctuates a relative position between an optical member including at least either one of the first optical member OP1 and the second optical member OP2 and the target holding part 110; and a control part 160 which drives the drive part 150 on the basis of a displacement.SELECTED DRAWING: Figure 1

Description

[Technical field]

[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. [Background technology]

[0002] Patent Document 1 describes a light source in which a target material is formed on the surface of a cylindrical member that rotates around a rotation axis, and the formed target material is irradiated with excitation light to emit illumination light.

[0003] Patent document 2 describes a light source that uses centrifugal force to hold a molten metal target material on the inner wall of a crucible that rotates around an axis of rotation, and emits illumination light by irradiating the held target material with excitation light. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-077007 A [Patent Document 2] JP 2022-168463 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a light source device, the relative position between the light emitting point located near the surface of the target material and the optical member may fluctuate due to vibrations that occur when a target holder such as a cylindrical member or a crucible rotates, deformation of the structure itself, deformation of the target holder itself due to rotational stress and heat, and the introduction of a target material into the target holder, etc. This may result in a case where light cannot be stably extracted from the light source device.

[0006] The object of the present disclosure has been made to solve such problems, and 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. [Means for solving the problem]

[0007] The light source device according to the present disclosure includes an input optical system including a first optical member that irradiates a target material with excitation light, an output optical system including a second optical member that extracts light generated by irradiating the target material with the excitation light, a target holding unit that holds the target material, an acquisition unit that acquires a displacement of a surface position of the target material, a drive unit that varies a relative position between an optical member including at least one of the first optical member and the second optical member and the target holding unit, and a control unit that drives the drive unit based on the displacement.

[0008] In the light source device, the acquisition section may acquire an amount of displacement of the surface position, and the control section may drive the drive section with a control amount based on the amount of displacement.

[0009] In the above light source device, the control unit may drive the drive unit so that a relative position between the optical element and a surface position of the target material held by the target holding unit remains approximately constant before and after the displacement.

[0010] In the above light source device, the acquisition unit acquires the displacement of the surface position of the target material from a reference position, and the control unit may drive the drive unit so that the relative position of the optical member and the surface position of the target material held in the target holding unit at the time of the displacement of the surface position of the target material is approximately identical to the relative position of the optical member and the surface position of the target material held in the target holding unit when the surface position of the target material is at the reference position.

[0011] In the above light source device, when the acquisition unit acquires a displacement of the surface position exceeding a predetermined threshold value, the control unit may drive the drive unit so as to vary the relative position between the optical element and the target holding unit.

[0012] In the above light source device, when the acquisition unit acquires a displacement of the surface position that exceeds the predetermined threshold in a direction toward the optical member, the control unit may drive the drive unit so as to change the relative position between the optical member and the target holding unit.

[0013] In the light source device, the target holding section may move the target material to an irradiation position where the excitation light is irradiated, in association with the movement of the target holding section.

[0014] In the above light source device, the target holding portion rotates around a rotation axis, the target material moves to the irradiation position as the target holding portion rotates around the rotation axis, and the control portion may drive the drive portion so that the relative position between the optical member and the target holding portion changes in a direction that includes a component perpendicular to the rotation axis.

[0015] In the above light source device, the control unit may drive the drive unit so that the relative position between the optical member and the target holding unit changes in a direction that includes a component parallel to the optical axis of the excitation light irradiating the target material.

[0016] In the light source device, a rotation speed of the target holding part about the rotation axis may be substantially constant before and after the relative position varies.

[0017] The target holding unit may rotate around a rotation axis, the target material may move to the irradiation position as the target holding unit rotates around the rotation axis, and the control unit may drive the drive unit so that the relative position between the optical member and the target holding unit changes in a direction that includes a component parallel to the rotation axis.

[0018] In the light source device described above, the target material may include molten metal, and the target holding portion may include a container that holds the target material therein, and the target material may be held on an inner wall surface of the container by centrifugal force.

[0019] The light source device may further include a position sensor that acquires the surface position of the target material based on the distance to the liquid surface of the molten metal, and the acquisition unit may acquire the displacement of the surface position from the surface position acquired by the position sensor.

[0020] In the above light source device, the acquisition unit acquires the displacement of the surface position at the irradiation position by predicting the displacement of the surface position at the irradiation position from the displacement of the surface position at a position in front of the irradiation position in the direction of the movement of the target holding unit, and the control unit may control the driving unit based on the predicted displacement of the surface position.

[0021] In the light source device described above, when the surface position is displaced at a predetermined period, the control unit may control the drive unit based on the period.

[0022] In the light source device described above, the control unit may cause the drive unit to vary a position of the target holding unit such that the relative position between the optical member and the target holding unit varies.

[0023] The light source device may further include a stage on which the target holding portion and the optical member are placed, and when changing the relative position of the target holding portion and the optical member, the control portion may change the position of the stage by the driving portion and change the position of the optical member by the driving portion.

[0024] In the light source device, the second optical member may include a collector mirror that reflects the generated light.

[0025] In the light source device, the first optical member may include a condenser lens that condenses the excitation light.

[0026] In the light source device, the light may include EUV light.

[0027] An inspection apparatus according to the present disclosure includes the above-described light source device, and an inspection optical system that inspects an inspection object with the light extracted from the output optical system.

[0028] An exposure apparatus according to the present disclosure includes the light source device described above, and an exposure optical system that exposes an exposure target with the light extracted from the output optical system.

[0029] The light source control method according to the present disclosure includes the steps of holding a target material with a target holding unit, acquiring a displacement of a surface position of the target material with an acquisition unit, varying a relative position between an optical member including at least one of a first optical member and a second optical member and the target holding unit based on the displacement, irradiating excitation light onto the target material with an input optical system including the first optical member, and extracting light generated by irradiating the target material with the excitation light with an output optical system including the second optical member.

[0030] The inspection method according to the present disclosure includes a step of inspecting an object to be inspected with the light extracted by the above-described light source control method.

[0031] The exposure method according to the present disclosure includes a step of exposing an exposure target with the light extracted by the above-described light source control method. Effect of the Invention

[0032] According to the present disclosure, it is possible to provide a light source device, an inspection apparatus, an exposure apparatus, a light source control method, an inspection method, and an exposure method that improve the stability of light extracted from a light source device. [Brief description of the drawings]

[0033] [Figure 1] 1 is a cross-sectional view illustrating a light source device according to a first embodiment. [Diagram 2] 3 is a perspective view illustrating a container serving as a target holding portion in the light source device according to the first embodiment. FIG. [Diagram 3] 1 is a plan view illustrating a light source device according to a first embodiment. [Figure 4] 2 is a block diagram illustrating a sensor, an acquisition unit, a drive unit, and a control unit in the light source device according to the first embodiment. FIG. [Diagram 5] 4 is a flowchart illustrating a light source control method using the light source device according to the first embodiment. [Figure 6] 1 is a configuration diagram illustrating an inspection device equipped with a light source device according to a first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Hereinafter, a specific configuration of the present embodiment will be described with reference to the drawings. The following description shows a preferred embodiment of the present disclosure, and the scope of the present disclosure is not limited to the following embodiment. In the following description, parts with the same reference numerals indicate substantially the same contents.

[0035] (Embodiment 1) A light source device according to a first embodiment will be described. The light source device of this embodiment generates light such as illumination light and exposure light used in optical devices such as an inspection device and an exposure device. The light source device may be provided integrally with the optical device, or may be disposed near the optical device as a separate entity from the optical device. When the optical device is an inspection device, the light source device generates illumination light that illuminates an inspection object in the inspection device. When the optical device is an exposure device, the light source device generates exposure light that exposes an exposure object in the exposure device.

[0036] The light source device generates light such as illumination light and exposure light by irradiating excitation light onto a target material held in a target holding unit. In the following, an example of a light source device in which molten metal held in a container is used as a target material will be described. Note that the light source device is not limited to one in which the target material is molten metal held in a container, and may be one in which the target material is liquid metal in droplet form, solid metal fixed to a cylindrical drum, or the like.

[0037] Fig. 1 is a cross-sectional view illustrating a light source device 100 according to embodiment 1. Fig. 2 is a perspective view illustrating a container 111 as a target holding unit 110 in the light source device 100 according to embodiment 1. Fig. 3 is a plan view illustrating the light source device 100 according to embodiment 1. Fig. 4 is a block diagram illustrating the sensor 140, the acquisition unit 145, the drive unit 150, and the control unit 160 in the light source device 100 according to embodiment 1.

[0038] As shown in Figs. 1 to 4, the light source device 100 includes a stage STG, a target holding unit 110, an input optical system 120, an output optical system 130, a sensor 140, an acquisition unit 145, a drive unit 150, and a control unit 160. The sensor 140 may include a position sensor 141. The drive unit 150 may include drive units 151 to 153. In Fig. 1, the acquisition unit 145 and the control unit 160 are connected to only some members to avoid cluttering the drawing, but they may be connected to other members. In Fig. 3, some members are omitted.

[0039] On the stage STG, the target holder 110, the input optical system 120, the output optical system 130, at least a part of the sensor 140, and at least a part of the drive unit 150 in the light source device 100 are placed. The acquisition unit 145 and the control unit 160 may be placed on the stage STG. The stage STG may include, for example, a stone surface plate. Here, for convenience of explanation of the light source device 100, an XYZ Cartesian coordinate system is introduced in which the vertical direction is the Z-axis direction. Note that the introduced XYZ Cartesian coordinate system is for convenience of explanation and does not limit the orientation of each member. The stage STG is movable in the X-axis direction, the Y-axis direction, and the Z-axis direction. In addition, the stage STG may rotate around an axis such as the X-axis, the Y-axis, and the Z-axis as a rotation axis. The stage STG is driven by the drive unit 151 so as to move and rotate.

[0040] The target holding part 110 is placed on the stage STG. Therefore, the target holding part 110 moves together with the movement of the stage STG. The target holding part 110 holds a target material 112. The target holding part 110 is, for example, a container 111 such as a crucible. The container 111 is capable of melting metal inside. The container 111 holds the target material 112 such as molten metal that generates plasma 127 by irradiation with excitation light LR. The excitation light LR is, for example, laser light including IR (Infrared) light.

[0041] The target holding unit 110 is not limited to the container 111, and may be a cylindrical drum. In this case, the target holding unit 110 holds the target material 112 by fixing a solid metal, such as xenon (Xe), which becomes the target material 112, on the surface of the drum.

[0042] The target material 112 may include a molten metal. The target material 112 is not limited to the molten metal held in the container 111, and may be a solid metal, liquid droplets, or the like, as long as it is a substance that generates plasma 127 when irradiated with the excitation light LR. The molten metal is, for example, melted tin (Sn) or lithium (Li), but is not limited to tin or lithium, as long as it is a substance that generates plasma 127 when irradiated with the excitation light LR.

[0043] The container 111 has a rotation axis R and rotates around the rotation axis R. The container 111 has, for example, a cylindrical shape with one opening closed. The closed part of the container 111 is called a bottom 113. The cylindrical part of the container 111 is called a cylindrical part 114. The inner surface of the bottom 113 is called a bottom surface 115. The inner surface of the cylindrical part 114 is called an inner wall surface 116. A groove 117 may be formed at the joint between the bottom 113 and the cylindrical part 114. The container 111 may have a shape other than the above as long as it can hold molten metal.

[0044] The target holding unit 110 holds the target material 112 on the inner wall surface 116 of the container 111 by centrifugal force. The inner wall surface 116 formed to surround the rotation axis R may include a cylindrical portion whose distance from the rotation axis R is constant from the upper end to the lower end, or may be barrel-shaped with a bulging intermediate portion between the upper end and the lower end. The inner wall surface 116 may also include a cone-shaped portion that widens outward as it approaches the top. For example, the cone-shaped portion of the inner wall surface 116 may be connected to a groove 117.

[0045] In addition to the target holding unit 110, the light source device 100 may also include a heater 118 and a debris shield 119. A target material 112 such as a molten metal can be formed in the container 111 by heating with the heater 118. The debris shield 119 is disposed at an opening 111a of the container 111 so as to cover the target material 112.

[0046] As the container 111 rotates about the rotation axis R, the target material 112 also rotates about the rotation axis R. As shown in Fig. 3, for example, the target material 112 located at position P1 facing the position sensor 141 at time t1 moves to the irradiation position PS at time t2 as the container 111 rotates. In this way, as the target holding part 110 moves (i.e., rotates), the target material 112 moves to the irradiation position PS where the excitation light LR is irradiated.

[0047] The input optical system 120 includes a first optical member OP1. The first optical member OP1 irradiates the target material 112 with the excitation light LR. The first optical member OP1 includes, for example, at least one of a mirror 121 and a condenser lens 122. Note that the first optical member OP1 is not limited to the mirror 121 and the condenser lens 122, and may be a laser LS that generates the excitation light LR, as long as it is an optical member that irradiates the target material 112 with the excitation light LR.

[0048] The first optical member OP1 in the input optical system 120 is placed on the stage STG. The first optical member OP1 may be fixed to a chamber CMB placed on the stage STG. In either case, the first optical member OP1 moves in association with the movement of the stage STG. The first optical member OP1 is connected to a driving unit 152 and is driven to move and rotate by the driving unit 152. Therefore, the first optical member OP1 may be driven to move by the driving unit 152 after, before, or simultaneously with the movement in association with the movement of the stage STG.

[0049] The first optical member OP1 irradiates the target material 112 with the excitation light LR at an angle tilted from an axis perpendicular to the surface of the target material 112. Specifically, for example, the first optical member OP1 irradiates the surface of the irradiation position PS where the excitation light LR is irradiated with the excitation light LR at an inclined incident angle. By irradiating the excitation light LR at an inclined angle in this manner, it is possible to suppress the influence of debris on optical members including the collector mirror 131 and the like. The reason why the influence of debris on optical members such as the collector mirror 131 can be suppressed will be explained below.

[0050] When the excitation light LR is irradiated from a direction perpendicular to the surface of the target material 112, the debris scatters in all directions centered on the direction perpendicular to the surface. This may cause the debris to adhere to the collector mirror 131 facing the irradiation position PS. On the other hand, when the excitation light LR is irradiated to the surface of the irradiation position PS at an inclined incidence angle, the debris can be scattered in the reflection direction opposite to the incidence direction of the excitation light LR. This makes it possible to suppress the adhesion of the debris to the collector mirror 131. Furthermore, when the excitation light LR is irradiated at an incidence angle inclined toward the front side of the irradiation position PS with respect to the direction of movement of the target holder 110, an angular velocity in the rotation direction of the container 111 is added to the direction in which the debris scatters, so that the debris can be further scattered in the reflection direction of the excitation light LR. In this way, the influence of the debris on optical members such as the collector mirror 131 can be suppressed.

[0051] The mirror 121 reflects the excitation light LR generated by the laser LS toward the irradiation position PS of the target material 112. The mirror 121 may include, for example, a mirror such as a piezo steering mirror. Note that the mirror 121 is not limited to a piezo steering mirror and may include a galvanometer mirror, a polygon mirror, or the like, as long as it can reflect the excitation light LR toward the target material 112. The focusing lens 122 focuses the excitation light LR at the irradiation position PS of the target material 112.

[0052] The light source device 100 may include a laser LS that generates excitation light LR. On the other hand, the light source device 100 may introduce the excitation light LR from a laser LS that is installed outside the light source device 100 separately from the light source device 100 to the light source device 100. When the laser LS is a part of the light source device 100, the laser LS may be placed on the stage STG. The laser LS may be fixed to a chamber CMB placed on the stage STG. In either case, the laser LS may move in association with the movement of the stage STG. The laser LS may be connected to a driving unit 152 and driven to move and rotate by the driving unit 152. Therefore, the laser LS may be driven to move by the driving unit 152 after, before, or simultaneously with the movement in association with the movement of the stage STG.

[0053] The laser LS emits, for example, excitation light LR including IR light. The excitation light LR may be irradiated onto the target material 112 by the control of oscillation and stoppage of the control unit 160. For example, the excitation light LR is reflected by a mirror 121 and condensed by a condenser lens 122. As a result, the excitation light LR irradiates the target material 112.

[0054] The output optical system 130 includes a second optical member OP2. The second optical member OP2 extracts the light L0 generated by irradiating the target material 112 with the excitation light LR from the light source device 100. The second optical member OP2 includes, for example, a collector mirror 131. Note that the second optical member OP2 is not limited to the collector mirror 131, and may be a second collector mirror (not shown) that further reflects the light L0 reflected by the collector mirror 131, as long as it is an optical member that extracts the light L0 generated by irradiating the target material 112 with the excitation light LR.

[0055] The second optical member OP2 in the output optical system 130 is placed on the stage STG. The second optical member OP2 may be fixed to a chamber CMB placed on the stage STG. In either case, the second optical member OP2 moves in association with the movement of the stage STG. The second optical member OP2 is connected to a driving unit 153 and is driven to move and rotate by the driving unit 153. Therefore, the second optical member OP2 may be driven to move by the driving unit 153 after, before, or simultaneously with the movement in association with the movement of the stage STG.

[0056] The collector mirror 131 reflects the light L0 generated from the target material 112 by irradiation with the excitation light LR. The collector mirror 131 reflects, for example, the EUV light LE generated by irradiation with 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 generated by irradiating the target material 112 with the excitation light LR. The EUV light LE generated from the plasma 127 generated in the target material 112 is emitted as illumination light to an optical device such as an inspection device. Therefore, the illumination light includes the EUV light LE generated from the plasma 127.

[0057] The sensor 140 may include various sensors such as a temperature sensor, a stress sensor, etc. in addition to the position sensor 141. The position sensor 141 actually measures and acquires the surface position of the target material 112. Specifically, the position sensor 141 may include, for example, a displacement meter, a high-speed camera, a low-speed camera, a four-division PD (Photo Diode), or a TDI (Time Delay Integration) camera. The position sensor 141 may measure the surface position in one dimension, two dimensions, or three dimensions, or may be a combination of several sensors.

[0058] The sensor 140 including the position sensor 141 etc. is connected to the acquisition unit 145 and the control unit 160 in a state capable of transmitting information. The sensor 140 outputs the acquired information on the surface position of the target material 112 to the acquisition unit 145 and the control unit 160. The acquisition unit 145 is connected to the sensor 140 and the control unit 160 in a state capable of transmitting information. The acquisition unit 145 acquires the displacement of the surface position of the target material 112 based on the surface position of the target material 112 acquired by the position sensor 141. The acquisition unit 145 outputs the acquired information on the displacement of the surface position to the control unit 160.

[0059] The position sensor 141 may actually measure and acquire the surface position of the target material 112 at the irradiation position PS where the excitation light LR irradiates the target material 112. In this case, the acquisition unit 145 acquires the displacement of the surface position at the irradiation position PS. However, if the position sensor 141 is disposed at a position opposite the irradiation position PS so that the surface position at the irradiation position PS can be actually measured and acquired, there is a risk of being affected by debris. In addition, since plasma 127 is generated at the irradiation position PS, there is a risk that the surface position cannot be acquired accurately.

[0060] Therefore, it is desirable to arrange the position sensor 141 so as to face a peripheral position away from the irradiation position PS. The peripheral position includes a portion of the inner wall surface 116 of the container 111 other than the irradiation position PS. For example, the position sensor 141 may be arranged so as to face a position P1 on the opposite side of the irradiation position PS with respect to the rotation axis R. This makes it possible to suppress the influence of debris and improve the measurement accuracy of the surface position. Note that the position sensor 141 may be arranged to face not only the position P1 but also a peripheral position other than the position P1 as long as the influence of debris can be reduced.

[0061] In this way, the position sensor 141 may actually measure and acquire the surface positions at peripheral positions other than the irradiation position PS. In this case, the acquisition unit 145 may acquire the displacement of the surface positions at the peripheral positions from the surface positions at the peripheral positions acquired by the position sensor 141, and further predict the displacement of the surface position at the irradiation position PS. The acquisition unit 145 may also predict the displacement of the surface position of the target material 112 taking into consideration the inclination and vibration of the target holder 110 with respect to the rotation axis.

[0062] For example, the position sensor 141 acquires the surface position at a position in front of the irradiation position PS in the direction of movement of the target holding unit 110. The acquisition unit 145 acquires the displacement of the surface position at a peripheral position in front of such irradiation position PS, and predicts the displacement of the surface position at the irradiation position PS from the acquired displacement. At this time, the acquisition unit 145 can predict the displacement of the surface position at the irradiation position PS at the time (irradiation time) when the excitation light LR reaches the irradiation position PS by taking into account the movement speed (rotation speed) of the target holding unit 110. In this way, the acquisition unit 145 acquires the displacement of the surface position at the irradiation position PS by predicting the displacement of the surface position at the irradiation position PS.

[0063] The position sensor 141 may acquire the surface position of the target material 112 as a relative position with respect to the second optical member OP2. Then, the acquisition unit 145 may acquire the displacement of the surface position of the target material 112 as a displacement of the relative position with respect to the second optical member OP2. Specifically, the position sensor 141 may actually measure and acquire the surface position of the target material 112 at the irradiation position PS as a relative position with respect to the second optical member OP2, or may actually measure and acquire the surface position at the peripheral position as a relative position with respect to the second optical member OP2. Thus, the acquisition unit 145 may acquire the displacement of the surface position of the target material 112 at the irradiation position PS as a displacement of the relative position with respect to the second optical member OP2, or may acquire the displacement of the surface position at the peripheral position as a displacement of the relative position with respect to the second optical member OP2.

[0064] The position sensor 141 may acquire 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. Therefore, the acquisition unit 145 may acquire the displacement of 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. In addition, when the target material 112 is a solid metal fixed to a cylindrical drum, the position sensor 141 may acquire the surface position of the target material 112 based on the thickness of the surface of the solid metal from the upper surface (surface surface) of the drum, as well as the tilt and vibration amount of the drum. The acquisition unit 145 may acquire the displacement of the surface position of the target material 112 based on the thickness of the surface of the solid metal from the upper surface (surface surface) of the drum, as well as the tilt and vibration amount of the drum. In addition, the position sensor 141 may acquire the surface position of the target material 112 by measuring the distance from the position sensor 141 to the surface position of the target material 112.

[0065] The acquiring unit 145 may combine the position sensor 141 with another sensor to acquire the displacement of the surface position at the irradiation position PS. In this way, the displacement of the surface position due to the temperature change of each member of the light source device 100 and the displacement of the surface position due to the stress change can be compensated for by the other sensor. Specifically, the acquiring unit 145 may correct the displacement of the surface position of the target material 112 based on the temperature change acquired by the temperature sensor provided in the target holding unit 110. Also, the acquiring unit 145 may correct the displacement of the surface position of the target material 112 based on the stress change acquired by the stress sensor provided in the target holding unit 110. Also, the acquisition of the displacement of the surface position by the acquiring unit 145 may include detecting that the displacement of the surface position has occurred at that time (i.e. acquiring the fact of the displacement) or calculating the amount of the displacement. For example, the acquisition unit 145 may detect that the surface position of the target material 112 at that time point has been displaced from the surface position of the target material 112 at the time point when the excitation light LR was previously irradiated onto the target material 112, or may calculate the amount of such displacement, or may detect that the surface position of the target material 112 has been displaced from a reference surface position (i.e., a reference position of the surface position), or may calculate the amount of such displacement. Furthermore, acquisition of the displacement of the surface position by the acquisition unit 145 may include prediction of the occurrence of displacement of the surface position or the amount of displacement at a future time point (for example, the time point when the excitation light LR is irradiated). For example, the acquisition unit 145 may predict that the surface position of the target material 112 at the time when the target material 112 is irradiated with the excitation light LR will be displaced from the surface position of the target material 112 at the time when the target material 112 was previously irradiated with the excitation light LR, or may predict the amount of displacement; the acquisition unit 145 may also predict that the surface position of the target material 112 at the time when the target material 112 is irradiated with the excitation light LR will be displaced from a reference position, or may predict the amount of displacement.

[0066] The driving unit 150 includes a driving unit 151, a driving unit 152, and a driving unit 153. The driving unit 150 may further include other driving units. In particular, when the driving unit 151, the driving unit 152, and the driving unit 153 are not specified, the driving units 151, the driving unit 152, and the driving unit 153 are collectively referred to as the driving unit 150. The driving unit 150 may be replaced with at least one of the driving units 151, the driving unit 152, and the driving unit 153, or at least one of the driving units 151, the driving unit 152, and the driving unit 153 may be replaced with the driving unit 150, as appropriate. Each driving unit 150 and each driving unit 152 can be driven independently.

[0067] The driving unit 150 is connected to the control unit 160 in a state in which information can be transmitted. The driving unit 150 receives a control amount for driving the driving unit 150 calculated by the control unit 160. The driving unit 150 varies the relative position between the target optical member and the target holding unit 110 based on the control amount.

[0068] The driving unit 150 varies the relative position between an optical member including at least one of a first optical member OP1 and a second optical member OP2 and the target holding unit 110. For convenience of explanation, an optical member including at least one of the first optical member OP1 and the second optical member OP2 is called a target optical member. The driving unit 150 varies the relative position between the target optical member and the target holding unit 110 so that the relative position between the target optical member and the surface position of the target material 112 held by the target holding unit 110 remains approximately constant before and after the displacement of the surface position of the target material 112. For example, when the acquisition unit 145 acquires the displacement of the surface position of the target material 112 from the reference position (the occurrence of the displacement or the amount of displacement is predicted or detected), the drive unit 150 varies the relative position between the target optical member and the target holding unit 110 so that the relative position between the target optical member and the surface position of the target material 112 held by the target holding unit 110 is substantially the same as the relative position between the target optical member and the surface position of the target material 112 when the surface position of the target material 112 is at the reference position. The reference position of the surface position of the target material 112 here may be the surface position of the target material 112 at the time when the target material 112 was previously irradiated with the excitation light LR, or may be a surface position defined in advance when setting up the optical device. It may also be a position defined by other methods.

[0069] The driver 150 may vary the relative position between the target optical member and the target holder 110 in a direction including a component perpendicular to the rotation axis R of the target holder 110, or in a direction including a component parallel to the rotation axis R. For example, the position of the target holder 110 may be varied or moved in a direction along the rotation axis R. Alternatively, the position may be varied in a direction parallel to the optical axis of the excitation light LR irradiating the target material 112. Note that the rotation speed of the target holder 110 around the rotation axis R may be approximately constant before and after the driver 150 varies the relative position.

[0070] The driving unit 151 varies the position of the stage STG. In the case where the chamber CMB is fixed to the stage STG, the driving unit 151 varies the position of the chamber CMB together with the stage STG. The driving unit 151 varies the position of the stage STG, for example, in the X-axis direction, the Y-axis direction, and the Z-axis direction. Furthermore, the driving unit 151 rotates and moves the stage STG around the X-axis, the Y-axis, and the Z-axis. The driving unit 151 may include, for example, an actuator. Note that the driving unit 151 is not limited to an actuator as long as it can vary the position of the stage STG.

[0071] The driving unit 152 changes the position of the first optical member OP1. For example, the driving unit 152 changes the position of the first optical member OP1 in the X-axis direction, the Y-axis direction, and the Z-axis direction. In addition, the driving unit 152 rotates the first optical member OP1 around the X-axis, the Y-axis, and the Z-axis.

[0072] The driving unit 152 may vary the position of the focal point of the first optical member OP1. The driving unit 152 is, for example, an actuator. Note that the driving unit 152 is not limited to an actuator as long as it can vary the position of the first optical member OP1. The driving unit 152 drives the first optical member OP1 so as to change the irradiation direction of the excitation light LR. For example, when the first optical member OP1 is a mirror 121, the driving unit 152 performs beam scanning by changing the angle of the mirror 121 with respect to the excitation light LR. Specifically, the driving unit 152 changes the reflecting surface of the mirror 121 so that the excitation light LR scans the surface of the target material 112 in a predetermined direction.

[0073] When mirror 121 is a piezo steering mirror, driving unit 152 may include a driving mechanism provided on the piezo steering mirror. When mirror 121 is a galvanometer mirror, a polygon mirror, or the like, driving unit 152 may be a driving mechanism provided on the galvanometer mirror, the polygon mirror, or the like.

[0074] At the irradiation position PS where the excitation light LR irradiates the target material 112, plasma 127 is generated. The generated plasma 127 is observed as a bright spot. The driving unit 152 varies the optical axis of the mirror 121 to vary the position of the light focusing point. As a result, the driving unit 152 moves the bright spot at high speed to perform beam shaping. Therefore, when the optical device is an inspection device, it is possible to improve the uniformity and availability in the field of view detected by the detector of the inspection device.

[0075] When the excitation light LR is obliquely incident on the surface of the target material 112, if the surface position of the target material 112 is displaced, the bright spot moves in a direction having a component perpendicular to the optical axis in the field of view detected by the detector of the inspection device. By varying the reflecting surface of the mirror 121 in accordance with the displacement of the surface position, the displacement of the component perpendicular to the optical axis of the excitation light LR can be canceled.

[0076] Displacement of the bright spot in a direction parallel to the optical axis of the excitation light LR causes defocusing. Therefore, the driving unit 152 moves the position of the condenser lens 122 in a direction parallel to the optical axis of the excitation light LR. As a result, the driving unit 152 varies the position of the condenser point of the excitation light LR. In this way, when the first optical member OP1 includes the condenser lens 122, the driving unit 152 moves the position of the condenser lens 122 in a direction parallel to the optical axis of the excitation light LR.

[0077] The driving unit 153 changes the position of the second optical member OP2. For example, the driving unit 153 changes the position of the second optical member OP2 in the X-axis direction, the Y-axis direction, and the Z-axis direction. In addition, the driving unit 153 rotates the second optical member OP2 around the X-axis, the Y-axis, and the Z-axis.

[0078] The driving unit 153 may drive the second optical member OP2 so as to change the extraction direction of the generated light L0. When the surface position of the target material 112 is displaced, the optical path of the light L0 generated from the target material 112 is displaced. Therefore, in the case where the second optical member OP2 includes a collector mirror 131, the driving unit 153 performs beam scanning by changing the angle of the collector mirror 131 with respect to the light L0. The driving unit 153 is, for example, an actuator. Note that the driving unit 153 is not limited to an actuator as long as it can change the position of the second optical member OP2.

[0079] The displacement of the surface position of the target material 112 may include surface vibration caused by vibration due to rotation of the container 111, the drum, etc. propagated to the surface, and displacement due to consumption or replenishment of the target material 112. Replenishment of the target material 112 includes reflux of evaporated or scattered target material 112 back to the container 111 and the drum.

[0080] Of the displacements of the surface position of the target material 112, surface vibrations occur at high frequencies. Therefore, the mirror 121, such as a steering mirror that can be driven at high frequencies, is suitable for canceling surface vibrations.

[0081] On the other hand, the direction of the displacement of the surface position due to consumption and replenishment of the target material 112 is the same as the direction of the surface vibration described above. However, such displacement due to consumption and replenishment of the target material 112 is a low-frequency displacement. Therefore, the driving unit 152 drives the first optical member OP1 at a low frequency. Also, the displacement of the surface position due to consumption and replenishment of the target material 112 may be larger than the displacement of the surface position due to the surface vibration. In particular, when reflux is included, the displacement of the surface position of the target material 112 is significantly larger than the displacement of the surface position due to the surface vibration.

[0082] Therefore, in the case of displacement of the surface position due to consumption and replenishment of the target material 112, it is desirable to have the driving unit 151 change the position of the stage STG. The movement of the position of the stage STG by the driving unit 151 can change the relative position between the target optical member and the target holder 110 to a greater extent than the movement of the position of the target optical member by the driving units 152 and 153. In addition, the movement of the position of the stage STG by the driving unit 151 moves the entire chamber CMB, so that the deviation of the optical paths of the excitation light LR and the light L0 can be suppressed to a smaller range than the movement of the position of the target optical member by the driving units 152 and 153. Furthermore, since the driving unit 151 can change the position of the stage STG in a direction parallel to the optical axis of the excitation light LR, defocusing can be suppressed.

[0083] The control unit 160 drives the driving unit 150 based on the displacement of the surface position of the target material 112 acquired by the acquisition unit 145. Here, when it is acquired that the displacement of the surface position acquired by the acquisition unit 145 is predicted to be displaced by a predetermined threshold value or more, or that the displacement has been acquired, the control unit 160 may control the driving unit 150 to drive. Therefore, even if the surface position (the thickness of the target material 112 from the inner wall surface 116 and the drum surface) is displaced, if the displacement is not a predetermined threshold value or more, the control unit 160 may limit the execution of the control of the driving unit 150. Here, the displacement of the surface position by a predetermined threshold value or more may mean that the surface position is displaced from the reference position by a predetermined threshold value or more.

[0084] For example, when the acquisition unit 145 acquires a displacement of the surface position of the target material 112 from a reference position (the occurrence of the displacement or the amount of displacement is predicted or detected), the control unit 160 causes the drive unit 150 to vary the relative position between the target optical member and the target holding unit 110 so that the relative position between the target optical member and the surface position of the target material 112 held by the target holding unit 110 becomes substantially the same as the relative position between the target optical member and the surface position of the target material 112 when the surface position of the target material 112 is at the reference position. The reference position of the surface position of the target material 112 here may be the surface position of the target material 112 at the time when the target material 112 was previously irradiated with the excitation light LR, or may be a surface position defined in advance when setting up the optical device.

[0085] Note that a plurality of predetermined thresholds may be set in advance. For example, the predetermined thresholds may include a first threshold, a second threshold, a third threshold, and the like. For example, each threshold may be a threshold for driving the driving unit 151, or may be a threshold for driving the driving unit 152. Furthermore, each threshold may be a threshold for driving at least one of the driving units 150, or may be a threshold for driving all of the driving units 150.

[0086] The control unit 160 calculates a control amount for driving the driving unit 150 based on the displacement of the surface position of the target material 112 acquired by the acquisition unit 145. Then, the control unit 160 drives the driving unit 150 based on the calculated control amount. The control unit 160 drives the driving unit 150 so that the relative position between the target optical member and the surface position of the target material 112 held by the target holding unit 110 remains approximately constant before and after the displacement of the surface position.

[0087] There are cases where the surface position of the target material 112 increases or decreases suddenly. For example, as in the above-mentioned reflux, the surface position is suddenly displaced when the container 111 is replenished with the target material 112. The value of such a sudden displacement may be set to a predetermined threshold value in advance. Then, when the acquisition unit 145 acquires a displacement of the surface position exceeding the predetermined threshold value, the control unit 160 drives the drive unit 150 so that the relative position between the target optical member and the target holding unit 110 varies. For example, when the acquisition unit 145 acquires a displacement of the surface position exceeding the predetermined threshold value in a direction in which the target optical member approaches the target optical member due to reflux, that is, in a direction in which the thickness of the target material from the container inner wall or the drum surface increases (for example, in the -Y axis direction in FIG. 1), the control unit 160 drives the drive unit 150 and the like so that the relative position between the target optical member and the target holding unit 110 varies.

[0088] When varying the relative position between the target optical member and the target holding unit 110, the control unit 160 drives the drive unit 150 so that the relative position varies in a direction including a component perpendicular to the rotation axis R. The control unit 160 also drives the drive unit 150 so that the relative position varies in a direction including a component parallel to the rotation axis R. The control unit 160 also drives the drive unit 150 so that the relative position varies in a direction parallel to the optical axis of the excitation light LR irradiating the target material 112.

[0089] The control unit 160 may control the driving unit 150 based on the displacement of the surface position acquired as the state at that time. That is, the control unit 160 may control the driving unit 150 based on the displacement of the surface position acquired (detected) in real time by the acquisition unit 145. The control unit 160 may also control the driving unit 150 based on the displacement of the surface position at the irradiation position PS predicted from the displacement of the peripheral position. In this way, the control unit 160 may control (for example, feedforward control) so as to maintain the plasma generation position at a preferred position. That is, the acquisition unit 145 may acquire (predict) the displacement of the surface position at the irradiation position PS from the displacement of the surface position at a position before the irradiation position PS with respect to the direction of movement of the target holding unit 110, and the control unit 160 may control the driving unit 150 based on the acquired displacement of the surface position. In this way, the driving unit 150 changes the relative position between the target optical member and the target holding unit 110.

[0090] When the surface position of the target material 112 is displaced at a predetermined period, the acquisition unit 145 may predict the displacement of the surface position at a predetermined time based on the period. Then, the control unit 160 may control the driving unit 150 based on the displacement acquired (predicted) by the acquisition unit 145. This may control (e.g., feedforward control) so as to maintain the plasma generation position at a preferable position. For example, when the displacement of the surface position includes a surface vibration that oscillates at a predetermined period, the acquisition unit 145 may calculate the period of the surface vibration, and the acquisition unit 145 may acquire (predict) the displacement of the surface position at a predetermined time (e.g., when the excitation light LR is irradiated) based on the calculated period, and the control unit 160 may control the driving unit 150 based on the acquired displacement.

[0091] When changing the relative position between the target optical member and the target holder 110, the control unit 160 may cause the drive unit 151 to change the position of the target holder 110. For example, the control unit 160 causes the drive unit 151 to change the position of the stage STG. As a result, the drive unit 151 changes the position of the target holder 110.

[0092] Since the target holder 110 and the target optical member are placed on the stage STG, when the driver 151 changes the position of the stage STG, the position of the target optical member also changes together with the target holder 110. Therefore, when the controller 160 changes the relative position between the target optical member and the target holder 110, the controller 160 causes the driver 151 to change the position of the stage STG, and then, before or at the same time, causes the driver 152 and the driver 153 to change the position of the target optical member. Specifically, for example, when the acquirer 145 acquires a displacement of the surface position exceeding a predetermined threshold in a direction approaching the target optical member (for example, the -Y axis direction, hereinafter referred to as the first direction) due to the replenishment of the target material 112 by reflux or the like, the controller 160 causes the driver 151 to change the position of the stage STG in a second direction (+Y axis direction) opposite to the first direction. Then, before or at the same time, the control unit 160 causes the driving units 152 and 153 to vary the position of the target optical member in the first direction (-Y axis direction). This cancels the displacement of the surface position of the target material 112, and the relative position between the target optical member and the surface position of the target material 112 can be made substantially constant before and after the displacement. Note that the first direction and the second direction are merely examples, and may include a component in the X axis direction and a component in the Z axis direction.

[0093] When the first optical member OP1 includes a mirror 121, the control unit 160 may control the driving unit 152 to vary the optical axis of the mirror 121 to vary the position of the focal point. When the first optical member OP1 includes a condenser lens 122, the control unit 160 may control the driving unit 152 to move the condenser lens 122 in a direction parallel to the optical axis of the excitation light LR to vary the position of the focal point. Furthermore, when the second optical member OP2 includes a collector mirror 131, the control unit 160 may control the driving unit 153 to vary the optical axis of the collector mirror 131 to vary the optical axis of the generated light L0. The control unit 160 may drive the driving units 152 and 153 so that the light L0 scans the visual field of the inspection target of the inspection device.

[0094] <Light source control method> Next, a light source control method using the light source device 100 will be described. Fig. 5 is a flow chart illustrating a light source control method using the light source device 100 according to the first embodiment. As shown in step S11 in Fig. 5, first, the target material 112 is held by the target holding unit 110. For example, the target material 112 such as a molten metal that generates plasma 127 by irradiation with excitation light LR is held in a container 111 such as a crucible.

[0095] Next, as shown in step S12, the acquisition unit 145 acquires the displacement of the surface position of the target material 112. For example, the acquisition unit 145 may acquire the displacement of the surface position from the surface positions at the peripheral positions acquired by the position sensor 141, and predict the displacement of the surface position at the irradiation position PS. In this way, the acquisition unit 145 acquires the displacement of the surface position at the irradiation position PS.

[0096] Next, as shown in step S13, the relative position between the target optical member including at least one of the first optical member OP1 and the second optical member OP2 and the target holding unit 110 is changed by the driving unit 150 based on the acquired displacement of the surface position. Specifically, based on the displacement amount of the surface position acquired by the acquisition unit 145, the control unit 160 is caused to calculate the control amount by which the driving unit 150 drives the target optical member and the stage STG. Then, the control unit 160 drives the driving unit 150 with the control amount based on the displacement amount.

[0097] The drive unit 150 varies the position of the stage STG and the position of the target optical member so that the relative position between the target optical member and the surface position of the target material 112 held by the target holding unit 110 remains approximately constant before and after the displacement of the surface position.

[0098] Next, as shown in step S14, the target material 112 is irradiated with excitation light LR by the input optical system 120 including the first optical member OP1.

[0099] Next, as shown in step S15, the light L0 generated by irradiating the target material 112 with the excitation light LR is extracted by the output optical system 130 including the second optical member OP2. In this manner, by controlling the light source device 100, the light L0 to be used in the optical device can be extracted.

[0100] <Optical equipment> Next, an optical device will be described. In the following, an inspection device will be used as an example of the optical device.

[0101] FIG. 6 is a configuration diagram illustrating an inspection apparatus 1 including a light source device 100 according to the first embodiment. As shown in FIG. 6, the inspection apparatus 1 includes an illumination optical system 200, an inspection optical system 300, a detector 410, and an image processing unit 420. The inspection apparatus 1 may further include the light source device 100. The inspection apparatus 1 is an apparatus that uses light L0 generated by the light source device 100 as illumination light L1 to inspect defects and the like of a sample 500. The sample 500 is, for example, an EUV mask. The sample 500 is not limited to an EUV mask, and may be a semiconductor substrate or the like.

[0102] The illumination optical system 200 has an ellipsoidal mirror 210, an ellipsoidal mirror 220, and a drop-in mirror 230. The inspection optical system 300 has a concave mirror with a hole 310, a convex mirror 320, a plane mirror 330, and a concave mirror 340. The concave mirror with a hole 310 and the convex mirror 320 configure a Schwarzschild magnification optical system.

[0103] The light source device 100 generates illumination light L1. The illumination light L1 includes, for example, EUV light LE of 13.5 nm, which is the same as the exposure wavelength of the EUV mask that is the sample 500. The illumination light L1 may include light other than EUV light. The illumination light L1 generated from the light source device 100 is reflected by the ellipsoidal mirror 210. The illumination light L1 reflected by the ellipsoidal mirror 210 advances while being narrowed, and is collected at a convergence point IF1. Therefore, the ellipsoidal mirror 210 reflects the illumination light L1 generated from the light source device 100 as a convergent light. The convergence point IF1 is located at a position conjugate to the upper surface 510 of the sample 500 such as an EUV mask and the detection surface 411 of the detector 410.

[0104] After passing through the convergence point IF1, the illumination light L1 advances while expanding and is incident on a reflecting mirror such as the ellipsoidal mirror 220. Therefore, the illumination light L1 reflected by the ellipsoidal mirror 210 is incident on the ellipsoidal mirror 220 as divergent light via the convergence point IF1. The illumination light L1 incident on the ellipsoidal mirror 220 is reflected by the ellipsoidal mirror 220, advances while being narrowed, and is incident on the drop-in mirror 230. In other words, the ellipsoidal mirror 220 reflects the incident illumination light L1 as convergent light. Then, the ellipsoidal mirror 220 causes the illumination light L1 to be incident on the drop-in mirror 230. The drop-in mirror 230 is disposed directly above the EUV mask. The illumination light L1 incident on and reflected by the drop-in mirror 230 is incident on the sample 500. Therefore, the drop-in mirror 230 reflects the illumination light L1 reflected by the ellipsoidal mirror 220 to the sample 500, thereby causing the illumination light L1 to be incident on the sample 500.

[0105] The ellipsoidal mirror 220 focuses the illumination light L1 on the sample 500. The illumination optical system 200 is installed so that, when the illumination light L1 illuminates the sample 500, an image of the light source device 100 is formed on the upper surface 510 of the sample 500. Therefore, the illumination optical system 200 provides critical illumination. In this manner, the illumination optical system 200 illuminates the sample 500, such as an EUV mask, using critical illumination by the illumination light L1 generated by the light source device 100.

[0106] The sample 500 is placed on a stage 520. Here, a plane parallel to an upper surface 510 of the sample 500 is defined as an αβ plane, and a direction perpendicular to the αβ plane is defined as a γ axis direction. Illumination light L1 is incident on the sample 500 from a direction tilted from the γ axis direction. That is, illumination light L1 is incident obliquely to illuminate the sample 500.

[0107] The stage 520 is a three-dimensional drive stage having 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 γ-axis direction.

[0108] The illumination light L1 from the light source device 100 illuminates an inspection area of ​​the sample 500. The inspection area illuminated by the illumination light L1 is, for example, 0.5 mm square. The inspection area is not limited to 0.5 mm square. The illumination light L1 is incident on the sample 500 from a direction tilted with respect to the γ-axis direction. The light from the sample 500 illuminated by the illumination light L1 is incident on the perforated concave mirror 310. In the following, the light from the sample 500 illuminated by the illumination light L1 is described as reflected light L2. The light incident on the perforated concave mirror 310 from the sample 500 is not limited to the reflected light L2, and may include diffracted light and the like. The reflected light L2 reflected by the sample 500 is incident on the perforated concave mirror 310. A hole 311 is provided at the center of the perforated concave mirror 310. The perforated concave mirror 310 collects the reflected light L2 from the sample 500, and reflects the collected reflected light L2 as convergent light.

[0109] The reflected light L2 reflected by the concave mirror 310 with a hole is incident on the convex mirror 320. The convex mirror 320 reflects the reflected light L12 reflected by the concave mirror 310 with a hole toward the hole 311 of the concave mirror 310 with a hole. The reflected light L2 passing through the hole 311 is incident on the plane mirror 330. The plane mirror 330 causes the reflected light L2 reflected by the convex mirror 320 to be incident as convergent light through the hole 311 of the concave mirror 310 with a hole. The reflected light L2 incident on the plane mirror 330 is reflected by the plane mirror 330. The reflected light L2 reflected by the plane mirror 330 advances while being narrowed, and is collected at the convergence point IF2. Therefore, the plane mirror 330 reflects the incident reflected light L2 as convergent light. The convergence point IF2 is sometimes called an aperture stop. The focal point IF 2 is located at a position conjugate with the upper surface 510 of the sample 500 and the detection surface 411 of the detector 410 .

[0110] After passing through the convergence point IF2, the reflected light L2 advances while diverging and enters the concave mirror 340. Thus, the reflected light L2 reflected by the plane mirror 330 as convergent light enters the concave mirror 340 as divergent light via the convergence point IF2. The concave mirror 340 reflects the incident reflected light L2 as convergent light toward the detector 410. The reflected light L2 reflected by the concave mirror 340 is detected by the detector 410. In this manner, the inspection optical 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 inspection optical system 300 collects the reflected light L2 from the sample 500 illuminated by the illumination light L1, and guides the collected reflected light L2 to the detector 410.

[0111] 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. The area on the sample 500 detected by the detector 410 is called a field of view 511. The detector 410 receives reflected light L2 from the field of view 511 illuminated by the illumination light L1. The field of view 511 may be included in the inspection area illuminated by the illumination light L1. The detector 410 acquires image data of the sample 500, such as an EUV mask. When the detector 410 includes a TDI sensor, the detector 410 includes a plurality of imaging elements arranged in a line in one direction. The imaging elements are, for example, CCDs (Charge Coupled Devices). Note that the imaging elements are not limited to CCDs.

[0112] 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, an information processing device such as a server device or a personal computer.

[0113] The reflected light L2 contains information about defects in the sample 500. The specularly reflected light of the illumination light L1 incident on the sample 500 from a direction tilted with respect to the Z-axis direction is detected by the inspection optical system 300. If a defect exists in the sample 500, the defect is observed as a dark image. This observation method is called bright-field observation. Note that the inspection apparatus 1 may also cause the illumination light L1 to be incident on the sample 500 from the Z-axis direction and detected by the inspection optical system 300. If a defect exists in the sample 500, the defect is observed as a bright image. This observation method is called dark-field observation.

[0114] In this manner, the inspection apparatus 1 of the present embodiment includes the light source device 100 described above and the inspection optical system 300 that inspects the inspection object with the light L0 extracted from the output optical system 130. The inspection method using the inspection apparatus 1 includes a step of inspecting the inspection object with the light L0 extracted by the light source control method described above. Although the inspection apparatus 1 has been described as an optical apparatus, the optical apparatus may be an exposure apparatus. For example, the exposure apparatus includes the light source device 100 described above and an exposure optical system that exposes the exposure object with the light L0 extracted from the output optical system 130. The control unit 160 may drive the drive unit 150 so that the light L0 scans the exposure area on the exposure object. The exposure method using the exposure apparatus includes a step of exposing the exposure object with the light L0 extracted by the light source control method described above.

[0115] Next, the effects of this embodiment will be described. The light source device 100 of this embodiment drives the drive unit 150 with a control amount based on the displacement of the surface position of the target material 112. As a result, the light source device 100 varies the relative position between the target optical member including at least one of the first optical member OP1 and the second optical member OP2 and the target holding unit 110. Therefore, even if the surface position of the target material 112 is displaced due to vibration and consumption of the target material 112, the focal point varies following the displacement, so that the stability of the light L0 extracted from the light source device 100 can be improved.

[0116] When a displacement of the surface position exceeding a preset threshold value is acquired, such as a relatively large displacement of the surface position due to consumption and replenishment of the target material 112, the control unit 160 drives the drive unit 150 so as to vary the relative position between the target optical member and the target holding unit 110. Thus, the target optical member and the target holding unit 110 to be driven can be determined in advance depending on the degree of displacement of the surface position, so that the position of an appropriate member can be varied.

[0117] The acquiring unit 145 acquires the displacement of the surface position of the peripheral positions other than the irradiation position PS, and predicts the displacement of the surface position of the irradiation position PS from the acquired displacement of the surface position of the peripheral positions. Specifically, the acquiring unit 145 predicts the displacement of the surface position of the irradiation position PS from the displacement of the surface position at a position before the irradiation position PS with respect to the direction of movement of the target holding unit 110. Therefore, the control unit 160 can drive the driving unit 150 based on the predicted displacement of the surface position so that the relative position between the target optical member and the target holding unit 110 is approximately constant before and after the displacement. This allows the focusing point of the excitation light LR to be aligned with the surface position at the irradiation position PS, thereby improving the stability of the light L1. Furthermore, the control unit 160 may calculate a control amount based on the predicted displacement of the surface position and control (for example, feedforward control) the driving unit 150. Therefore, the focusing point can be changed following the displacement of the surface position.

[0118] The target holding unit 110 holds the target material 112 on the inner wall surface 116 by the centrifugal force of the rotating container 111. This makes it possible to make the surface position of the target material 112 uniform, thereby improving the stability of the light L1.

[0119] When varying the relative position between the target holding unit 110 and the target optical member, the control unit 160 causes the driving unit 151 to vary the position of the stage STG, and then, before that or simultaneously, causes the driving units 152 and 153 to vary the position of the target optical member. This makes it possible to keep the relative position between the target optical member and the target material 112 approximately constant before and after the displacement, even with respect to a relatively large displacement of the surface position due to consumption and replenishment of the target material 112, and also makes it possible to suppress defocusing.

[0120] Although the embodiments of the present disclosure have been described above, the present disclosure includes appropriate modifications that do not impair the objects and advantages thereof, and is not limited to the above-mentioned embodiments. In the embodiments of the present disclosure, the target holder 110 is a container 111 such as a crucible, but the target holder 110 is not limited to this, and may be one that holds the target material 112 on the surface of a cylindrical object, or one that holds the target material 112 with a tape-like object, etc. Furthermore, the configurations of the first embodiment may be combined as appropriate. [Explanation of symbols]

[0121] 1. Inspection equipment 100 Light source device 110 Target holder 111 Container 111a opening 112 Target material 113 Bottom 114 Cylindrical part 115 Bottom 116 Inner Wall 117 Groove 118 Heater 119 Debris Shield 120 Input Optical System 121 Mirror 122 Condenser Lens 127 Plasma 130 Output Optical System 131 Collector Mirror 140 Sensors 141 Position Sensor 145 Acquisition Department 150, 151, 152, 153 Drive unit 160 Control section 200 Illumination optical system 210 Ellipsoidal Mirror 220 Ellipsoidal Mirror 230 Drop-in mirror 300 Inspection Optical System 310 Holed concave mirror 311 holes 320 Convex mirror 330 plane mirror 340 concave mirror 410 Detector 411 Detection surface 420 Image Processing Unit 500 samples 510 Top surface 511 Field of view 520 Stage 530 Drive unit CMB Chamber L0 light L1 illumination light LE EUV light LR excitation light LS Laser OP1 First optical member OP2 Second optical member P1 position PS irradiation position R rotation axis STG Stage

Claims

1. an input optical system including a first optical member that irradiates the target material with excitation light; an output optical system including a second optical member that extracts light generated by irradiating the target material with the excitation light; A target holder for holding the target material; an acquisition unit that acquires a displacement of a surface position of the target material; a drive unit that changes a relative position between an optical member including at least one of the first optical member and the second optical member and the target holding unit; A control unit that drives the drive unit based on the displacement; A light source device comprising:

2. The acquisition unit acquires a displacement amount of the surface position, The control unit drives the drive unit with a control amount based on the displacement amount. The light source device according to claim 1 .

3. the control unit drives the drive unit so that a relative position between the optical member and a surface position of the target material held by the target holding unit remains substantially constant before and after the displacement. The light source device according to claim 1 .

4. The acquisition unit acquires the displacement of the surface position of the target material from a reference position, the control unit drives the drive unit so that a relative position between the optical member and the surface position of the target material held in the target holding unit during the displacement of the surface position of the target material is substantially the same as a relative position between the optical member and the surface position of the target material held in the target holding unit when the surface position of the target material is at the reference position. The light source device according to claim 1 .

5. When the displacement of the surface position exceeding a predetermined threshold is acquired by the acquisition unit, the control unit drives the drive unit so as to vary a relative position between the optical member and the target holding unit. The light source device according to claim 1 .

6. When the displacement of the surface position exceeding the predetermined threshold in a direction toward the optical member is acquired by the acquisition unit, the control unit drives the drive unit so that a relative position between the optical member and the target holding unit changes. The light source device according to claim 5 .

7. The target holding unit moves the target material to an irradiation position where the excitation light is irradiated, in accordance with the movement of the target holding unit. The light source device according to claim 1 .

8. The target holder rotates about a rotation axis, the target material moves to the irradiation position in accordance with the rotational movement of the target holder about the rotation axis; the control unit drives the drive unit so that a relative position between the optical member and the target holding unit varies in a direction including a component in a direction perpendicular to the rotation axis. The light source device according to claim 7.

9. the control unit drives the drive unit so that a relative position between the optical member and the target holding unit varies in a direction including a component in a direction parallel to an optical axis of the excitation light irradiating the target material. The light source device according to claim 8 .

10. a rotation speed of the target holding part about the rotation axis is substantially constant before and after the relative position is changed; The light source device according to claim 8 .

11. The target holder rotates about a rotation axis, the target material moves to the irradiation position in accordance with the rotational movement of the target holder about the rotation axis; the control unit drives the drive unit so that a relative position between the optical member and the target holding unit varies in a direction including a component in a direction parallel to the rotation axis. The light source device according to claim 7.

12. the target material comprises molten metal; the target holder includes a container for holding the target material therein, and holds the target material on an inner wall surface of the container by centrifugal force. The light source device according to claim 1 .

13. a position sensor that acquires the surface position of the target material based on a distance to a liquid surface of the molten metal; The acquisition unit acquires the displacement of the surface position from the surface position acquired by the position sensor. The light source device according to claim 12.

14. the acquisition unit acquires the displacement of the surface position of the irradiation position by predicting the displacement of the surface position of the irradiation position from the displacement of the surface position at a position before the irradiation position with respect to the direction of the movement of the target holding unit; The control unit controls the drive unit based on the predicted displacement of the surface position. The light source device according to claim 7.

15. When the surface position is displaced at a predetermined period, the control unit controls the drive unit based on the period. The light source device according to claim 1 .

16. the control unit causes the drive unit to vary a position of the target holding unit such that the relative position between the optical member and the target holding unit varies. The light source device according to claim 1 .

17. a stage on which the target holder and the optical member are placed, The control unit is When changing the relative position between the target holder and the optical member, the position of the stage is changed by the drive unit; The position of the optical member is changed by the driving unit. The light source device according to claim 1 .

18. The second optical member includes a collector mirror that reflects the generated light. The light source device according to claim 1 .

19. The first optical member includes a condenser lens that condenses the excitation light. The light source device according to claim 1 .

20. The light includes EUV light. The light source device according to claim 1 .

21. The light source device according to any one of claims 1 to 20, an inspection optical system that inspects an inspection object with the light extracted from the output optical system; An inspection device equipped with

22. The light source device according to any one of claims 1 to 20, an exposure optical system that exposes an exposure target with the light extracted from the output optical system; An exposure apparatus comprising:

23. Holding the target material with a target holder; acquiring a displacement of a surface position of the target material by an acquisition unit; a step of causing a drive unit to vary a relative position between an optical member including at least one of a first optical member and a second optical member and the target holding unit based on the displacement; Irradiating the target material with excitation light using an input optical system including the first optical member; extracting light generated by irradiating the target material with the excitation light using an output optical system including the second optical member; A light source control method comprising:

24. An inspection method comprising the step of inspecting an inspection object with the light extracted by the light source control method according to claim 23.

25. 24. An exposure method comprising the step of exposing an exposure object with the light extracted by the light source control method according to claim 23.

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