Optical device and method for manufacturing optical device

Abstract

To provide an optical device and a method for manufacturing the optical device, with which it is possible to improve inspection throughput.SOLUTION: An inspection device 1 according to the present embodiment comprises: an optical system 20 for illuminating an object 50 by critical illumination with a plasma as a bright point; detection means 30 for detecting a secondary beam from the object 50 illuminated by critical illumination; and plasma forming means 10 for forming at least a first bright point 11 and a second bright point 12 as the bright point. The optical system 20 illuminates a first region 51 of the object 50 with a first critical illumination by first illumination light L11 generated from the first bright point 11, and illuminating a second region 52 of the object 50 with a second critical illumination by second illumination light L12 generated from the second bright point 12. The detection means 30 includes first detection means 31 for detecting a first beam L21 from the object 50, and second detection means 32 for detecting a second beam L22 from the object 50.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an optical device and a method for controlling an optical device. [Background technology]

[0002] Patent Document 1 discloses a technique for inspecting an EUV mask using a plasma bright spot as critical illumination. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-009274 Summary of the Invention [Problem to be solved by the invention]

[0004] It is desirable to increase inspection throughput.

[0005] The present disclosure has been made in consideration of such problems, and provides an optical device and a method for controlling an optical device that can improve inspection throughput. [Means for solving the problem]

[0006] An optical device according to one aspect of this embodiment comprises an optical system that illuminates an object with critical illumination in which plasma is a bright spot; a detection means that detects secondary light rays from the object illuminated with the critical illumination; and a plasma forming means that forms at least a first bright spot and a second bright spot as the bright spots. The optical system illuminates a first region of the object with first critical illumination using first illumination light generated from the first bright spot, and illuminates a second region of the object different from the first region with second critical illumination using second illumination light generated from the second bright spot. The detection means includes a first detection means that detects first light rays including the secondary light rays from the object illuminated with the first critical illumination, and a second detection means that detects second light rays including the secondary light rays from the object illuminated with the second critical illumination.

[0007] An optical device according to one aspect of this embodiment comprises an optical system that illuminates an object with critical illumination using plasma as a bright spot, and a detection means that detects secondary light rays from the object illuminated with the critical illumination, wherein the optical system includes a first elliptical mirror that illuminates a first region of the object with first critical illumination using first illumination light generated from a first light beam of light from the bright spot, and a second elliptical mirror that illuminates a second region of the object different from the first region with second critical illumination using second illumination light generated from a second light beam different from the first light beam of the light from the bright spot, and the detection means includes a first detection means that detects first light rays including the secondary light rays from the object illuminated with the first critical illumination, and a second detection means that detects second light rays including the secondary light rays from the object illuminated with the second critical illumination.

[0008] In the optical device described above, the optical system may illuminate the second area of ​​the object with the second critical illumination when illuminating the first area of ​​the object with the first critical illumination.

[0009] In the above optical device, the optical system may include a switching means for switching between a first mode in which the second area is illuminated with the second critical illumination and a second mode in which the first area is illuminated with the second critical illumination.

[0010] In the optical device, the first detecting means and the second detecting means may be provided alternately in a staggered manner when viewed from the optical axis direction of the first light beam and the second light beam.

[0011] In the above optical device, the optical system may include a first elliptical mirror having one focusing point at the position of the first bright spot and another focusing point at the position of the first region, and a second elliptical mirror having one focusing point at the position of the second bright spot and another focusing point at the position of the second region.

[0012] In the above optical device, the first elliptical mirror may have one focusing point at the position of the bright spot and another focusing point at the position of the first region, and the second elliptical mirror may have one focusing point at the position of the bright spot and another focusing point at the position of the second region.

[0013] In the optical device described above, a diaphragm may not be provided on the optical path of the first illumination light and the second illumination light from the bright point to the object.

[0014] A control method for an optical device according to one aspect of the present embodiment is a control method for an optical device including an optical system that illuminates an object with critical illumination in which plasma is a bright spot, a detection means that detects secondary light from the object illuminated with the critical illumination, and a plasma generation means that forms at least a first bright spot and a second bright spot as the bright spots, the control method including: a bright spot formation step that causes the plasma generation means to form at least a first bright spot and a second bright spot as the bright spots; an illumination step that causes the optical system to illuminate a first region of the object with first critical illumination using first illumination light generated from the first bright spot, and to illuminate a second region of the object different from the first region with second critical illumination using second illumination light generated from the second bright spot; and a detection step that causes a first detection means in the detection means to detect a first light ray including the secondary light from the object illuminated with the first critical illumination, and a second detection means in the detection means to detect a second light ray including the secondary light from the object illuminated with the second critical illumination.

[0015] A control method for an optical device according to one aspect of this embodiment is a control method for an optical device including an optical system that illuminates an object with critical illumination using plasma as a bright spot, and a detection means that detects secondary rays from the object illuminated with the critical illumination, and includes an illumination step of causing a first elliptical mirror in the optical system to illuminate a first region of the object with first critical illumination using first illumination light generated from a first light beam of light from the bright spot, and causing a second elliptical mirror in the optical system to illuminate a second region of the object different from the first region with second critical illumination using second illumination light generated from a second light beam different from the first light beam of light from the bright spot; and a detection step of causing a first detection means in the detection means to detect first rays including the secondary rays from the object illuminated with the first critical illumination, and causing a second detection means in the detection means to detect second rays including the secondary rays from the object illuminated with the second critical illumination.

[0016] In the above-mentioned method for controlling an optical device, in the illumination step, the optical system may be caused to illuminate the second area of ​​the object with the second critical illumination when illuminating the first area of ​​the object with the first critical illumination.

[0017] The above-mentioned method for controlling an optical device may further include a switching step of causing the switching means to switch between a first mode in which the second area is illuminated with the second critical illumination and a second mode in which the first area is illuminated with the second critical illumination.

[0018] In the above-described method for controlling an optical device, the first detecting means and the second detecting means may be provided alternately in a staggered manner when viewed from the optical axis direction of the first light beam and the second light beam.

[0019] In the above-mentioned method for controlling an optical device, in the illumination step, the first region may be illuminated with a first elliptical mirror having one focusing point at the position of the first bright spot and another focusing point at the position of the first region, and the second region may be illuminated with a second elliptical mirror having one focusing point at the position of the second bright spot and another focusing point at the position of the second region.

[0020] In the above-mentioned method for controlling an optical device, in the illumination step, the first elliptical mirror may have one focusing point at the position of the bright spot and another focusing point at the position of the first region, and the second elliptical mirror may have one focusing point at the position of the bright spot and another focusing point at the position of the second region.

[0021] In the above-described method for controlling an optical device, in the illuminating step, a diaphragm may not be provided on the optical path of the first illumination light and the second illumination light from the bright point to the object. [Effects of the Invention]

[0022] According to the present disclosure, it is possible to provide an optical device and a method for controlling an optical device that can improve inspection throughput. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a configuration diagram illustrating an inspection device according to a first embodiment. [Figure 2] 3 is a diagram illustrating an example of the arrangement of a first detecting means and a second detecting means in the inspection device according to the first embodiment. FIG. [Figure 3] 3 is a diagram illustrating an example of the arrangement of a first detecting means and a second detecting means in the inspection device according to the first embodiment. FIG. [Figure 4] FIG. 3 is a flowchart illustrating a control method for the inspection device according to the first embodiment. [Figure 5] FIG. 10 is a configuration diagram illustrating an inspection device according to a first modified example of the first embodiment. [Figure 6] FIG. 10 is a configuration diagram illustrating an inspection device according to a second modification of the first embodiment. [Figure 7] FIG. 10 is a flowchart illustrating a control method for an inspection device according to a second modification of the first embodiment. [Figure 8] FIG. 10 is a configuration diagram illustrating an inspection device according to a second embodiment. [Figure 9] FIG. 10 is a flowchart illustrating a control method for the inspection device according to the second embodiment. [Figure 10] FIG. 10 is a configuration diagram illustrating an inspection device according to a first modified example of the second embodiment. [Figure 11] FIG. 10 is a flowchart illustrating a control method for an inspection device according to a first modification of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The following description shows preferred embodiments of the present disclosure, and the scope of the present disclosure is not limited to the following embodiments. In the following description, components with the same reference numerals indicate substantially similar content.

[0025] <Embodiment 1> An optical device according to a first embodiment will be described. In the following, an inspection device will be described as an example of the optical device. Note that the optical device is not limited to an inspection device, and may be other devices such as a monitoring device or a manufacturing device. FIG. 1 is a configuration diagram illustrating an inspection device 1 according to a first embodiment. As shown in FIG. 1, the inspection device 1 includes a plasma generating means 10, an optical system 20, a detecting means 30, and a control unit 40.

[0026] The plasma generating means 10 forms at least a first bright spot 11 and a second bright spot 12 as bright spots. The plasma generating means 10 forms bright spots including the first bright spot 11 and the second bright spot 12 by generating plasma. The number of bright spots is not limited to two and may be three or more. For example, the plasma generating means 10 forms plasma generation points that become the first bright spot 11 and plasma generation points that become the second bright spot 12 by irradiating the target material 15 with a plurality of excitation lights LR1 and LR2. The excitation lights LR1 and LR2 are generated by, for example, a laser generator.

[0027] The target material 15 includes, for example, tin (Sn), lithium (Li), xenon ice, etc. The target material 15 may include materials other than tin, etc., as long as plasma can be formed by irradiation with excitation light LR1, etc. The method by which the plasma generating means 10 generates plasma is not limited to the method of irradiating the target material 15 with excitation light LR. The plasma generating means 10 may generate plasma by discharging the target material 15 placed between electrodes.

[0028] The first bright spot 11 and the second bright spot 12 formed by the plasma generating means 10 become bright spots that generate illumination light. The first illumination light L11 is generated from the first bright spot 11. The second illumination light L12 is generated from the second bright spot 12. The first illumination light L11 and the second illumination light L12 include EUV (Extreme Ultra Violet) light that is generated when plasma is generated.

[0029] The optical system 20 illuminates the object 50 with critical illumination using plasma as a bright spot. The object 50 may include, for example, a mask used in lithography using EUV light. The optical system 20 includes a mirror 23, a concave mirror 24, a mirror 25, a mirror 27, and a mirror 28. Note that the optical system 20 may include other optical components. The mirror 23 illuminates a first region 51 of the object 50 with first critical illumination using first illumination light L1 generated from the first bright spot 11. The mirror 23 also illuminates a second region 52 of the object 50 with second critical illumination using second illumination light L2 generated from the second bright spot 12. The optical system 20 may include a mirror other than the mirror 23 between the first bright spot 11 and the first region 51, as long as it can illuminate the first region 51 of the object 50 with first critical illumination using first illumination light L11 generated from the first bright spot 11. Furthermore, the optical system 20 may include a mirror other than the mirror 23 between the second bright point 12 and the second region 52, as long as the optical system 20 can illuminate the second region 52 of the object 50 with second critical illumination by the second illumination light L12 generated from the second bright point 12. The second region 52 of the object 50 is a region different from the first region 51. The mirror 23 includes, for example, a concave mirror. Note that the mirror 23 is not limited to a concave mirror, as long as the mirror 23 can illuminate the first region 51 with the first critical illumination and the second region 52 with the second critical illumination.

[0030] The first region 51 of the object 50 and the second region 52 of the object 50 are different regions of the same object 50. The first region 51 and the second region 52 may not overlap each other. The first region 51 and the second region 52 may be staggered. The second region 52 may be set at a position that is an integer multiple of the size of the first region 51 away from the first region 51. For example, when the scanning direction is the X axis, the second region 52 may be provided at a position that is an integer multiple of the size of the first region 51 away in the Y axis direction. When the scanning direction is the X axis, the second region 52 may be provided at a position that is an integer multiple of the size of the first region 51 away in the X axis direction. Furthermore, when the scanning direction is the X axis, the second region 52 may be provided at a position that is an integer multiple of the size of the first region 51 away in a direction intersecting the X axis and Y axis directions.

[0031] When illuminating a first region 51 of the object 50 with first critical illumination, the optical system 20 illuminates a second region 52 of the object 50 with second critical illumination. That is, the optical system 20 illuminates the second region 52 at the same timing as when illuminating the first region 51. This allows the states of the first region 51 and the second region 52 to be inspected in correspondence with each other at the same timing. Note that the optical system 20 may illuminate the second region 52 at a timing shifted from the timing at which it illuminates the first region 51. This, for example, can improve the degree of freedom in the irradiation timing of the excitation light L1 and L2.

[0032] In the inspection device 1 of this embodiment, in the optical system 20, an optical aperture does not need to be provided on the optical path of the first illumination light L11 and the second illumination light L12 from bright points such as the first bright point 11 and the second bright point 12 to the object 50.

[0033] Secondary light rays are emitted from the object 50 illuminated with the first critical illumination. For example, the secondary light rays may include at least one of reflected light of the first illumination light L11 reflected by the object 50, scattered light of the first illumination light L11 scattered by the object 50, diffracted light of the first illumination light L11 diffracted by the object 50, and light emitted from the object 50 due to excitation by the first illumination light L11. The secondary light rays from the object 50 illuminated with the first critical illumination are referred to as first light rays L21. Similarly, the secondary light rays from the object 50 illuminated with the second critical illumination are referred to as second light rays L22.

[0034] The first light ray L21 and the second light ray L22 are incident on the concave mirror 24. The concave mirror 24 has a hole 26 in the center. The first light ray L21 and the second light ray L22 that are incident on the concave mirror 24 are reflected by the concave mirror 24 and are incident on the mirror 25. The first light ray L21 and the second light ray L22 that are incident on the mirror 25 are reflected by the mirror 25.

[0035] The first light ray L21 reflected by the mirror 25 passes through the hole 26 and enters the mirror 27. The first light ray L21 is reflected by the mirror 27 and enters the first detecting means 31. On the other hand, the second light ray L22 reflected by the mirror 25 passes through the hole 26 and enters the mirror 28. The second light ray L22 is reflected by the mirror 28 and enters the second detecting means 32.

[0036] The detection means 30 detects secondary light rays from the object 50 illuminated by the critical illumination of the illumination light. The detection means 30 includes a first detection means 31 and a second detection means 32. The first detection means 31 detects a first light ray L21 including secondary light rays from the object 50 illuminated by the first critical illumination. The second detection means 32 detects a second light ray L22 including secondary light rays from the object 50 illuminated by the second critical illumination. The detection means 30, such as the first detection means 31 and the second detection means 32, may include an imaging element such as a CCD (Charge Coupled Device) or a CMOS sensor.

[0037] 2 and 3 are diagrams illustrating the arrangement of the first detecting means 31 and the second detecting means 32 in the inspection device 1 according to the first embodiment. As shown in FIG. 2, when viewed from the optical axis direction of the first light beam L21 and the second light beam L22, the first detecting means 31 and the second detecting means 32 may be arranged side by side in a direction perpendicular to the scanning direction. Also, as shown in FIG. 3, when viewed from the optical axis direction of the first light beam L21 and the second light beam L22, the first detecting means 31 and the second detecting means 32 may be arranged alternately in a staggered manner. For example, the first detecting means 31 and the second detecting means 32 may be arranged side by side in a direction intersecting the scanning direction and the stepping direction.

[0038] The inspection device 1 may include a control unit 40. The control unit 40 is connected to each component of the inspection device 1, such as the detection means 30 and the laser generator in the plasma generation means 10, via a wireless or wired communication line in a state in which information can be transmitted. The control unit 40 controls each component of the inspection device 1. The control unit 40 may be an information processing device such as a PC (Personal Computer), a server, or a microcomputer. Such an information processing device may further include a processor, a memory, a storage device, and a user interface. The storage device stores the processes to be executed by each component of the information processing device as a program. The processor also loads the program from the storage device into the memory and executes the program. In this way, the processor realizes the functions of each component of the information processing device. The user interface may include input devices such as a keyboard and a mouse, and output devices such as a display, a printer, and a speaker.

[0039] Fig. 4 is a flowchart illustrating a control method for the inspection device 1 according to embodiment 1. As shown in Fig. 4, the control method includes a bright spot forming step S11, an illumination step S12, and a detection step S13.

[0040] In the bright spot forming step S11, the control unit 40 causes the plasma forming means 10 to form at least a first bright spot 11 and a second bright spot 12 as bright spots.

[0041] In the illumination step S12, the control unit 40 causes the optical system 20 to illuminate a first region 51 of the object 50 with first critical illumination using the first illumination light L11 generated from the first bright spot 11, and to illuminate a second region 52 of the object 50 with second critical illumination using the second illumination light L12 generated from the second bright spot 12.

[0042] In the detection step S13, the control unit 40 causes the first detection means 31 in the detection means 30 to detect a first light ray L21 including a secondary light ray from the object 50 illuminated with the first critical illumination. At the same time, the control unit 40 causes the second detection means 32 in the detection means 30 to detect a second light ray L22 including a secondary light ray from the object 50 illuminated with the second critical illumination. In this way, the control unit 40 can control the inspection apparatus 1 to inspect the object 50.

[0043] Next, the effects of the inspection device 1 of this embodiment will be described. The inspection device 1 of this embodiment 1 forms a plurality of bright spots including at least a first bright spot 11 and a second bright spot 12. Then, the first illumination light L11 and the second illumination light L12 generated from the respective bright spots critically illuminate two different regions (a first region 51 and a second region 52) of the object 50. In this way, by performing critical illumination on different regions, the throughput of the inspection can be improved.

[0044] In a system that performs inspection at high magnification, it is necessary to increase the illumination intensity (irradiation density) on the object 50. However, if the illumination intensity is increased too much for an object 50 that includes a material with heat input limitations, deterioration of the object 50 occurs. In this embodiment, the illumination area on the object 50 is configured to include multiple areas, so that the power of the illumination light is dispersed into the first illumination light L11 and the second illumination light L12. Furthermore, by arranging the detection means 30 so that a position corresponding to the illumination area is observed, throughput can be improved.

[0045] In order to improve throughput, it is possible to increase the size of the detecting means 30 and process large amounts of data, but this poses a problem in terms of the physical size of the detecting means 30. In such cases, a method using multiple detecting means including the first detecting means 31 and the second detecting means 32, as in this embodiment, is effective.

[0046] <Variation 1-1> Next, a first modification of the first embodiment will be described. Fig. 5 is a configuration diagram illustrating an inspection device 1a according to the first modification of the first embodiment. As shown in Fig. 5, in the inspection device 1a, an optical system 20a includes a first elliptical mirror 21 and a second elliptical mirror 22 instead of the mirror 23.

[0047] The first elliptical mirror 21 illuminates a first region 51 of the object 50 with first critical illumination by first illumination light L11 generated from a first luminous flux of light from the first bright point 11. The optical system 20a may have another elliptical mirror or a mirror of another shape interposed between the first bright point 11 and the first region 51, other than the first elliptical mirror 21, as long as it can illuminate the first region 51 of the object 50 with first critical illumination by first illumination light L11 generated from any first luminous flux of light from the first bright point 11.

[0048] The second elliptical mirror 22 illuminates a second region 52 of the object 50 with second critical illumination by second illumination light L12 generated from a second luminous flux of light from the second bright point 12. The optical system 20a may include an elliptical mirror or a mirror of another shape other than the second elliptical mirror 22 between the second bright point 12 and the second region 52, as long as it can illuminate the second region 52 of the object 50 with second critical illumination by second illumination light L12 generated from an arbitrary second luminous flux different from the first luminous flux of light from the second bright point 12. The first luminous flux and the second luminous flux may be exclusive, i.e., none of the luminous fluxes included in the first luminous flux may be included in the second luminous flux, and none of the luminous fluxes included in the second luminous flux may be included in the first luminous flux.

[0049] First elliptical mirror 21 may have one light-converging point at the position of first bright spot 11. In this case, a mirror may be interposed to position one light-converging point of first elliptical mirror 21 at first bright spot 11 rather than at one focal position of first elliptical mirror 21. Such an example is also included in the first elliptical mirror 21 having one light-converging point at first bright spot 11. First elliptical mirror 21 may have the other light-converging point at first region 51. In this case, a mirror may be interposed to position the other light-converging point of first elliptical mirror 21 at first region 51 rather than at the other focal position of first elliptical mirror 21. Such an example is also included in the first elliptical mirror 21 having the other light-converging point at first region 51. Second elliptical mirror 22 may have one light-converging point at second bright spot 12. In this case, a mirror may be interposed to position one of the light-converging points of second elliptical mirror 22 at second bright spot 12 rather than at one of the focal points of second elliptical mirror 22. Such an example is also included in second elliptical mirror 22 having one light-converging point at second bright spot 12. Second elliptical mirror 22 may have the other light-converging point at second region 52. In this case, a mirror may be interposed to position the other light-converging point of second elliptical mirror 22 at second region 52 rather than at the other focal point of second elliptical mirror 22. Such an example is also included in second elliptical mirror 22 having the other light-converging point at second region 52. First elliptical mirror 21 may have one light-converging point at first bright spot 11 or the other light-converging point at first region 51. First elliptical mirror 21 may have one light-converging point at first bright spot 11 and the other light-converging point at first region 51. The second elliptical mirror 22 may have one focusing point at the position of the second bright spot 12 or the other focusing point at the position of the second region 52. The second elliptical mirror 22 may have one focusing point at the position of the second bright spot 12 and the other focusing point at the position of the second region 52. The first elliptical mirror 21 may have one focusing point at the position of the first bright spot 11 and the other focusing point at the position of the first region 51, and the second elliptical mirror 22 may have one focusing point at the position of the second bright spot 12 and the other focusing point at the position of the second region 52. Any of the above configurations allows the use of a minimum number of optical components and reduces optical loss of the first illumination light L11 and the second illumination light L12 due to the optical components.Therefore, the optical system 20a illuminates a first region 51 of the object 50 with high brightness in first critical illumination by the first illumination light L11 generated from the first bright spot 11, and illuminates a second region 52 of the object 50 with high brightness in second critical illumination by the second illumination light L12 generated from the second bright spot 12.

[0050] In the optical system 20a as well, an optical diaphragm does not need to be provided on the optical paths of the first illumination light L11 and the second illumination light L12 from the first bright point 11 and the second bright point 12 to the object 50.

[0051] According to this embodiment, the inspection device 1a has a first elliptical mirror 21 and a second elliptical mirror 22. Alignment of the optical system 20a can be easily performed by aligning one of the light-converging points of the first elliptical mirror 21 and the second elliptical mirror 22 with the positions of the first bright spot 11 and the second bright spot 12, respectively, and aligning the other of the light-converging points with the first region 51 and the second region 52, respectively. Furthermore, the first region 51 and the second region 52 can be efficiently illuminated with the first illumination light L11 and the second illumination light L12 incident on the first elliptical mirror 21 and the second elliptical mirror 22, thereby improving inspection accuracy.

[0052] <Variation 1-2> Next, a second modification of the first embodiment will be described. FIG. 6 is a configuration diagram illustrating an inspection apparatus 1b according to the second modification of the first embodiment. As shown in FIG. 6, in the inspection apparatus 1b, the optical system 20b further includes a switching unit 29. The switching unit 29 is attached to, for example, the second elliptical mirror 22. The switching unit 29 can change the orientation of the reflecting surface of the second elliptical mirror 22. As a result, the second illumination light L12, which has been illuminating the second region 52 with the second critical illumination, changes to illuminate the first region 51 with the second critical illumination. The mode in which the second region 52 is illuminated with the second critical illumination is referred to as the first mode. The mode in which the first region 51 is illuminated with the second critical illumination is referred to as the second mode. Thus, the switching unit 29 has a function of switching between the first mode and the second mode.

[0053] In addition, even when the optical system 20b illuminates the first region 51 of the object 50 with second critical illumination by the second illumination light L12 generated from the second bright spot 12, another elliptical mirror or a mirror of another shape other than the second elliptical mirror 22 may be interposed between the second bright spot 12 and the first region 51.

[0054] FIG. 7 is a flowchart illustrating a control method for the inspection apparatus 1b according to Modification 2 of Embodiment 1. As shown in FIG. 7, the control method for the inspection apparatus 1b according to Modification 2 further includes a switching step S10. In the switching step S10, the control unit 40 causes the switching means 29 to switch between a first mode in which the second region 52 is illuminated with the second critical illumination and a second mode in which the first region 51 is illuminated with the second critical illumination. Note that in FIG. 7, the switching step S10 is performed before the bright spot formation step S11, but this is not limiting. The switching step S10 may be performed after any of the bright spot formation step S11, the illumination step S12, and the detection step S13.

[0055] The inspection device 1b of this modified example is equipped with a switching means 29, and is therefore capable of switching between a first mode that improves inspection throughput and a second mode that increases the brightness of the first region 51 and improves inspection accuracy, thereby diversifying the inspection conditions.

[0056] <Embodiment 2> FIG. 8 is a configuration diagram illustrating an inspection device 2 according to a second embodiment. As shown in FIG. 8, in the inspection device 2 of this embodiment, the optical system 20c includes a first elliptical mirror 21 and a second elliptical mirror 22 instead of the mirror 23. Furthermore, the inspection device 2 of this embodiment does not need to include the plasma generating means 10 that forms the first bright spot 11 and the second bright spot 12. For example, the bright spot 13 may be formed by irradiating the target material 15 with excitation light L3. Note that the bright spot 13 is not limited to being formed by irradiation with excitation light L3, but may also be formed by discharging the target material 15 placed between electrodes.

[0057] The first elliptical mirror 21 illuminates a first region 51 of the object 50 with first critical illumination by the first illumination light L11 generated from the bright spot 13. In the optical system 20c, another elliptical mirror or a mirror of another shape may be interposed between the bright spot 13 and the first region 51, other than the first elliptical mirror 21, as long as the optical system 20c can illuminate the first region 51 of the object 50 with first critical illumination by the first illumination light L11 generated from the bright spot 13.

[0058] First elliptical mirror 21 may have one light-converging point at the position of bright spot 13. In this case, first elliptical mirror 21 also illuminates first region 51 of object 50 with first critical illumination by first illumination light L11 generated from bright spot 13. Note that at this time, a mirror may be interposed to position one light-converging point of first elliptical mirror 21 at the position of first bright spot 11 instead of one focus of first elliptical mirror 21. Such an example is also included in the case where one light-converging point of first elliptical mirror 21 is positioned at the position of first bright spot 11.

[0059] The second elliptical mirror 22 may have one of its light-converging points at the position of the bright spot 13. In this case, the second elliptical mirror 22 also illuminates the second region 52 of the object 50 with second critical illumination by the second bright light L12 generated from the bright spot 13. In this case, a mirror may be interposed to position one of the light-converging points of the second elliptical mirror 22 at the position of the second bright spot 12 instead of at one focus of the second elliptical mirror 22. Such an example is also included in the case where one of the light-converging points of the second elliptical mirror 22 is at the position of the second bright spot 12.

[0060] The first elliptical mirror 21 may have the other light-focusing point at the position of the first region 51. The second elliptical mirror 22 may have the other light-focusing point at the position of the second region 52. This increases the amount of light illuminating the object 50. In this case, a mirror may be interposed to position the other light-focusing point of the first elliptical mirror 21 at the position of the first region 51 instead of the other focal point of the first elliptical mirror, or a mirror may be interposed to position the other light-focusing point of the second elliptical mirror 22 at the position of the second region 52 instead of the other focal point of the second elliptical mirror. Such examples are also included in the case where the other light-focusing point of the first elliptical mirror 21 is positioned at the position of the first region 51 and the case where the other light-focusing point of the second elliptical mirror 22 is positioned at the position of the second region 52.

[0061] In this embodiment, no optical diaphragm is provided on the optical paths of the first illumination light L11 and the second illumination light L12 from the bright spot 13 to the object 50.

[0062] FIG. 9 is a flowchart illustrating a control method for the inspection apparatus 2 according to the second embodiment. As shown in FIG. 9, the control method for the inspection apparatus 2 according to the second embodiment includes an illumination step S21 and a detection step S22. In the illumination step S21, the control unit 40 may cause the first elliptical mirror 21, which has one of its focal points at the position of the bright spot 13 in the optical system 20c, to illuminate a first region 51 of the object 50 with first critical illumination using first illumination light L11 generated from the bright spot 13. At the same time, the control unit 40 may cause the second elliptical mirror 22, which has one of its focal points at the position of the bright spot 13 in the optical system 20c, to illuminate a second region 52 of the object 50 with second critical illumination using second illumination light L12 generated from the bright spot 13. The detection step S22 is similar to the detection step S13.

[0063] The inspection device 2 of this embodiment has a bright spot 13. Alignment of the optical system 20c can be facilitated by aligning the focusing point of one of the first elliptical mirror 21 and the second elliptical mirror 22 with the position of the bright spot 13. Furthermore, the first region 51 and the second region 52 can be efficiently illuminated with the first illumination light L11 and the second illumination light L12 incident on the first elliptical mirror 21 and the second elliptical mirror 22, thereby improving inspection accuracy.

[0064] <Variation 2-1> Next, a first modification of the second embodiment will be described. FIG. 10 is a configuration diagram illustrating an inspection apparatus 2a according to the first modification of the second embodiment. As shown in FIG. 10, in the inspection apparatus 2a, the optical system 20d further includes a switching unit 29. The switching unit 29 changes the orientation of the reflecting surface of the second elliptical mirror 22, for example. As a result, the second illumination light L12, which has been illuminating the second region 52 with the second critical illumination, changes to illuminate the first region 51 with the second critical illumination. As in the second modification of the first embodiment described above, the mode in which the second region 52 is illuminated with the second critical illumination is called the first mode, and the mode in which the first region 51 is illuminated with the second critical illumination is called the second mode. Therefore, the switching unit 29 has the function of switching between the first mode and the second mode.

[0065] In addition, even when the optical system 20d illuminates the first region 51 of the object 50 with second critical illumination by the second illumination light L12 generated from the bright spot 13, another elliptical mirror or a mirror of another shape other than the second elliptical mirror 22 may be interposed between the bright spot 13 and the first region 51.

[0066] FIG. 11 is a flowchart illustrating a control method for the inspection apparatus 2a according to Modification 1 of Embodiment 2. As shown in FIG. 11, the control method for the inspection apparatus 2a further includes a switching step S20. In the switching step S20, the control unit 40 causes the switching means 29 to switch between a first mode in which the second region 52 is illuminated with the second critical illumination and a second mode in which the first region 51 is illuminated with the second critical illumination. Note that in FIG. 11, the switching step S20 is performed before the illumination step S21, but this is not limiting. The switching step S20 may be performed after either the illumination step S21 or the detection step S22.

[0067] The inspection device 2a of this modified example is equipped with a switching means 29, and is therefore capable of switching between a first mode that improves inspection throughput and a second mode that increases the brightness of the first region 51 and improves inspection accuracy, thereby diversifying the inspection conditions.

[0068] 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-described embodiments. Furthermore, appropriate omissions and combinations of the configurations of Embodiments 1 and 2 and their modifications are also within the scope of the technical concept of the present disclosure. [Explanation of symbols]

[0069] 1, 1a, 1b, 2, 2a Inspection equipment 10. Plasma forming means 11 1st bright spot 12 Second bright spot 13 bright spot 15 Target material 20, 20a, 20b, 20c, 20d optics 21 First Elliptical Mirror 22 Second Elliptical Mirror 23. Mirror 24 concave mirror 25. Mirror 26 holes 27, 28 Mirror 29 Switching Methods 30 Detection means 31 First detection means 32 Second detection means 40 Control Unit 50 Objects 51 First area 52 Second area L11 First illumination light L12 2nd illumination light L21 1st ray L22 Second ray LR1, LR2, LR3 excitation light

Claims

1. an optical system that illuminates an object with critical illumination using plasma as a bright spot; a detection means for detecting a secondary ray from an object illuminated by the critical illumination; a plasma generating means for forming at least a first bright spot and a second bright spot as the bright spot; Equipped with The optical system comprises: illuminating a first region of the object with first critical illumination by first illumination light generated from the first bright point; illuminating a second area of ​​the object different from the first area with second critical illumination by second illumination light generated from the second bright point; The detection means a first detecting means for detecting a first ray including the secondary ray from the object illuminated with the first critical illuminant; a second detecting means for detecting a second light ray including the secondary light ray from the object illuminated with the second critical illumination; Including, optical equipment.

2. an optical system that illuminates an object with critical illumination using plasma as a bright spot; a detection means for detecting a secondary ray from an object illuminated by the critical illumination; Equipped with The optical system comprises: a first elliptical mirror for illuminating a first region of the object with first critical illumination by first illumination light generated from a first luminous flux of light from the bright spot; a second elliptical mirror that illuminates a second region of the object different from the first region with second critical illumination by second illumination light generated from a second light flux different from the first light flux of the light from the bright point; Including, The detection means a first detecting means for detecting a first ray including the secondary ray from the object illuminated with the first critical illuminant; a second detecting means for detecting a second light ray including the secondary light ray from the object illuminated with the second critical illumination; Including, optical equipment.

3. the optical system illuminates the second area of ​​the object with the second critical illumination when illuminating the first area of ​​the object with the first critical illumination; 3. The optical device according to claim 1.

4. the optical system includes a switching means for switching between a first mode in which the second region is illuminated with the second critical illumination and a second mode in which the first region is illuminated with the second critical illumination; 3. The optical device according to claim 1.

5. When viewed from the optical axis direction of the first light beam and the second light beam, the first detecting means and the second detecting means are provided alternately in a staggered manner.

3. The optical device according to claim 1.

6. The optical system comprises: a first elliptical mirror having one light-converging point at the position of the first bright point and another light-converging point at the position of the first region; a second elliptical mirror having one light-converging point at the position of the second bright point and another light-converging point at the position of the second region; Including, The optical device according to claim 1 .

7. the first elliptical mirror has one light-converging point at the position of the bright point and another light-converging point at the position of the first region; the second elliptical mirror has one light-converging point at the position of the bright point and another light-converging point at the position of the second region; 3. The optical device according to claim 2.

8. No diaphragm is provided on the optical paths of the first illumination light and the second illumination light from the bright point to the object.

8. The optical device according to claim 6 or 7.

9. an optical system that illuminates an object with critical illumination using plasma as a bright spot; a detection means for detecting a secondary ray from an object illuminated by the critical illumination; a plasma generating means for forming at least a first bright spot and a second bright spot as the bright spot; A method for controlling an optical device comprising: a bright spot forming step of causing the plasma generating means to form at least a first bright spot and a second bright spot as the bright spot; an illumination step of causing the optical system to illuminate a first region of the object with first critical illumination by first illumination light generated from the first bright point, and to illuminate a second region of the object different from the first region with second critical illumination by second illumination light generated from the second bright point; a detecting step of causing a first detecting means in the detecting means to detect a first light ray including the secondary light ray from the object illuminated with the first critical illumination, and causing a second detecting means in the detecting means to detect a second light ray including the secondary light ray from the object illuminated with the second critical illumination; A method for controlling an optical device comprising:

10. an optical system that illuminates an object with critical illumination using plasma as a bright spot; a detection means for detecting a secondary ray from an object illuminated by the critical illumination; A method for controlling an optical device comprising: an illumination step of causing a first elliptical mirror in the optical system to illuminate a first region of the object with first critical illumination using first illumination light generated from a first light beam of light from the bright point, and causing a second elliptical mirror in the optical system to illuminate a second region of the object different from the first region with second critical illumination using second illumination light generated from a second light beam different from the first light beam of the light from the bright point; a detecting step of causing a first detecting means in the detecting means to detect a first light ray including the secondary light ray from the object illuminated with the first critical illumination, and causing a second detecting means in the detecting means to detect a second light ray including the secondary light ray from the object illuminated with the second critical illumination; A method for controlling an optical device comprising:

11. In the illumination step, causing the optical system to illuminate the second area of ​​the object with the second critical illumination when illuminating the first area of ​​the object with the first critical illumination; 11. A method for controlling an optical device according to claim 9.

12. The method further includes a switching step of causing a switching unit to switch between a first mode in which the second region is illuminated with the second critical illumination and a second mode in which the first region is illuminated with the second critical illumination.

11. A method for controlling an optical device according to claim 9.

13. When viewed from the optical axis direction of the first light beam and the second light beam, the first detecting means and the second detecting means are provided alternately in a staggered manner.

11. A method for controlling an optical device according to claim 9.

14. In the illumination step, Illuminating the first area with a first elliptical mirror having one light-focusing point at the position of the first bright point and another light-focusing point at the position of the first area; The second region is illuminated by a second elliptical mirror having one light-focusing point at the position of the second bright point and another light-focusing point at the position of the second region. The method for controlling an optical device according to claim 9.

15. In the illumination step, the first elliptical mirror has one light-converging point at the position of the bright point and another light-converging point at the position of the first region; the second elliptical mirror has one light-converging point at the position of the bright point and another light-converging point at the position of the second region; The method for controlling an optical device according to claim 10.

16. In the illumination step, No diaphragm is provided on the optical paths of the first illumination light and the second illumination light from the bright point to the object.

16. A method for controlling an optical device according to claim 14 or 15.

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