Optical device and method for controlling the 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 Art

[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

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is desired to improve inspection throughput.

[0005] The present disclosure has been made in view 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 Problems

[0006] An optical apparatus according to one aspect of this embodiment includes an optical system for illuminating an object with critical illumination using plasma as a bright spot, detection means for detecting secondary rays from the object illuminated by the critical illumination, and plasma forming means for forming at least a first bright spot and a second bright spot as the bright spot, wherein 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, and the detection means includes a first detection means for detecting a first ray including the secondary rays from the object illuminated by the first critical illumination, and a second detection means for detecting a second ray including the secondary rays from the object illuminated by the second critical illumination.

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

[0008] In the optical apparatus described above, the optical system may illuminate a first region of the object with the first critical illumination, and illuminate a second region of the object with the second critical illumination.

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

[0010] In the optical device described above, the first detection means and the second detection means may be arranged alternately in a staggered pattern when viewed from the optical axis direction of the first and second rays.

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

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

[0013] In the optical device described above, an aperture does not need to be provided in the optical paths of the first illumination light and the second illumination light from the bright spot to the object.

[0014] A control method for an optical device according to one aspect of this embodiment includes: an optical system that illuminates an object with critical illumination using plasma as a bright spot; a detection means for detecting secondary rays from the object illuminated by the critical illumination; and a plasma forming means for forming at least a first bright spot and a second bright spot as the bright spot, comprising: a bright spot formation step of causing the plasma forming 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 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 of causing a first detection means in the detection means to detect a first ray including the secondary rays from the object illuminated by the first critical illumination, and causing a second detection means in the detection means to detect a second ray including the secondary rays from the object illuminated by 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 comprising: an optical system that illuminates an object with critical illumination using plasma as a bright spot; and a detection means for detecting secondary rays from the object illuminated by the critical illumination, 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 luminous 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 luminous beam different from the first luminous beam of light from the bright spot; and a detection step of causing a first detection means in the detection means to detect a first ray including the secondary rays from the object illuminated by the first critical illumination, and causing a second detection means in the detection means to detect a second ray including the secondary rays from the object illuminated by the second critical illumination.

[0016] In the above-described control method for the optical device, in the illumination step, the optical system may be instructed to illuminate a second region of the object with a second critical illumination when illuminating a first region of the object with the first critical illumination.

[0017] In the control method for the optical device described above, the switching means may further include a switching step that switches to a first mode in which the second region is illuminated with the second critical illumination, or a second mode in which the first region is illuminated with the second critical illumination.

[0018] In the control method for the optical device described above, the first detection means and the second detection means may be arranged alternately in a staggered pattern when viewed from the optical axis direction of the first and second rays.

[0019] In the above-described control method for the 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 the other 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 the other focusing point at the position of the second region.

[0020] In the control method for the optical device described above, in the illumination step, the first elliptical mirror may have one focusing point at the position of the bright spot and the other 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 the other focusing point at the position of the second region.

[0021] In the control method of the optical device described above, in the illumination step, an aperture does not need to be provided in the optical paths of the first illumination light and the second illumination light from the bright spot to the object. [Effects of the Invention]

[0022] This disclosure provides an optical device and a method for controlling the optical device that can improve inspection throughput. [Brief explanation of the drawing]

[0023] [Figure 1] It is a configuration diagram illustrating an inspection apparatus according to Embodiment 1. [Figure 2] It is a diagram illustrating the arrangement of the first detection means and the second detection means in the inspection apparatus according to Embodiment 1. [Figure 3] It is a diagram illustrating the arrangement of the first detection means and the second detection means in the inspection apparatus according to Embodiment 1. [Figure 4] It is a flowchart diagram illustrating a control method of the inspection apparatus according to Embodiment 1. [Figure 5] It is a configuration diagram illustrating an inspection apparatus according to Modification 1 of Embodiment 1. [Figure 6] It is a configuration diagram illustrating an inspection apparatus according to Modification 2 of Embodiment 1. [Figure 7] It is a flowchart diagram illustrating a control method of the inspection apparatus according to Modification 2 of Embodiment 1. [Figure 8] It is a configuration diagram illustrating an inspection apparatus according to Embodiment 2. [Figure 9] It is a flowchart diagram illustrating a control method of the inspection apparatus according to Embodiment 2. [Figure 10] It is a configuration diagram illustrating an inspection apparatus according to Modification 1 of Embodiment 2. [Figure 11] It is a flowchart diagram illustrating a control method of the inspection apparatus according to Modification 1 of Embodiment 2.

Mode for Carrying Out the Invention

[0024] ​​​​​​​An optical device according to Embodiment 1 will be described below. In the following, an inspection device will be described as an example of an optical device. Note that the optical device is not limited to an inspection device, but may also be other devices such as a monitoring device and a manufacturing device. Figure 1 is a configuration diagram illustrating an inspection device 1 according to Embodiment 1. As shown in Figure 1, the inspection device 1 comprises a plasma forming means 10, an optical system 20, a detection means 30, and a control unit 40.

[0026] The plasma forming means 10 forms at least a first bright spot 11 and a second bright spot 12 as bright spots. The plasma forming means 10 forms bright spots including the first bright spot 11 and the second bright spot 12 by generating plasma. Note that the number of bright spots is not limited to two, but may be three or more. The plasma forming means 10 forms plasma generation sites that will become the first bright spot 11 and plasma generation sites that will 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, for example, by a laser generator.

[0027] The target material 15 includes, for example, tin (Sn), lithium (Li), xenon ice, etc. However, the target material 15 may also include materials other than tin, etc., as long as it can form a plasma by irradiation with excitation light LR1, etc. Furthermore, the method by which the plasma forming means 10 forms the plasma is not limited to irradiating the target material 15 with excitation light LR. The plasma forming means 10 may also form the 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 forming 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 generated when the 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 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. The optical system 20 may also include other optical components. The mirror 23 illuminates the first illumination light generated from the first bright spot 11. L11 The first critical illumination by the mirror illuminates the first region 51 of the object 50. The mirror 23 also illuminates the second illumination light generated from the second bright spot 12. L12 The second critical illumination of the object 50 illuminates the second region 52 of the object 50. The optical system 20 may interpose a mirror other than mirror 23 between the first bright spot 11 and the first region 51 if the first critical illumination of the object 50 is enabled by the first illumination light L11 generated from the first bright spot 11. The optical system 20 may also interpose a mirror other than mirror 23 between the second bright spot 12 and the second region 52 if the second critical illumination of the object 50 is enabled by the second illumination light L12 generated from the second bright spot 12. The second region 52 of the object 50 is a different region from the first region 51. Mirror 23 includes, for example, a concave mirror. Note that mirror 23 is not limited to a concave mirror as long as it can illuminate the first region 51 with the first critical illumination and the second region 52 with the second critical illumination.

[0030] Note that the first region 51 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 be regions that do not overlap with each other. The first region 51 and the second region 52 may be staggered regions. The second region 52 may be set at a position that is an integer multiple of the size of the first region 51 from the first region 51. For example, when the scan direction is the X-axis, the second region 52 may be set at a position that is an integer multiple of the size of the first region 51 in the Y-axis direction. When the scan direction is the X-axis, the second region 52 may be set at a position that is an integer multiple of the size of the first region 51 in the X-axis direction. Also, when the scan direction is the X-axis, the second region 52 may be set at a position that is an integer multiple of the size of the first region 51 in a direction that intersects the X-axis and Y-axis directions.

[0031] The optical system 20 illuminates the first region 51 of the object 50 with the first critical illumination, and at the same time illuminates the second region 52 of the object 50 with the second critical illumination. In other words, the optical system 20 illuminates the second region 52 at the same time as illuminating the first region 51. This allows the state of the first region 51 and the state of the second region 52 to be inspected in correspondence at the same time. Alternatively, the optical system 20 may illuminate the second region 52 at a time staggered from the illumination of the first region 51. This allows for, for example, excitation light LR1 and LR2 This allows for greater flexibility in determining the timing of irradiation.

[0032] In the inspection apparatus 1 of this embodiment, in the optical system 20, it is not necessary to provide an optical aperture in the optical path of the first illumination light L11 and the second illumination light L12 from the bright spots such as the first bright spot 11 and the second bright spot 12 to the object 50.

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

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

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

[0036] The detection means 30 detects secondary 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 ray L21 including secondary rays from the object 50 illuminated by the first critical illumination. The second detection means 32 detects a second ray L22 including secondary rays from the object 50 illuminated by the second critical illumination. The detection means 30, including the first detection means 31 and the second detection means 32, is, for example, a CCD (Charge Coupled Device). CMOS It may include an image sensor or other image sensor.

[0037] Figures 2 and 3 illustrate the arrangement of the first detection means 31 and the second detection means 32 in the inspection apparatus 1 according to Embodiment 1. As shown in Figure 2, the first detection means 31 and the second detection means 32 may be arranged side by side in a direction perpendicular to the scanning direction when viewed from the optical axis direction of the first ray L21 and the second ray L22. Also, as shown in Figure 3, the first detection means 31 and the second detection means 32 may be arranged alternately in a staggered pattern when viewed from the optical axis direction of the first ray L21 and the second ray L22. For example, the first detection means 31 and the second detection means 32 may be arranged side by side in a direction intersecting the scanning direction and the step 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 forming means 10, in a manner that enables information transmission via wireless or wired communication lines. The control unit 40 controls each component of the inspection device 1. The control unit 40 may also be an information processing device such as a PC (Personal Computer), server, or microcomputer. Such an information processing device may further include a processor, memory, storage device, and user interface. The storage device stores programs of the processes to be performed by each component of the information processing device. The processor loads the programs from the storage device into memory and executes them. In this way, the processor realizes the functions of each component in the information processing device. The user interface may include input devices such as a keyboard and mouse, and output devices such as a display, printer, and speaker.

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

[0040] In the bright spot formation 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 illumination step S12, the control unit 40 causes the optical system 20 to 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, and to illuminate the second region 52 of the object 50 with second critical illumination using second illumination light L12 generated from the second bright spot 12.

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

[0043] Next, the effects of the inspection device 1 of this embodiment will be described. The inspection device 1 of this embodiment 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 each bright spot critically illuminate two different regions (first region 51 and second region 52) of the object 50. By performing critical illumination on different regions in this way, the inspection throughput can be improved.

[0044] In systems that perform inspections at high magnification, it is necessary to increase the illumination intensity (irradiation density) to the object 50. However, if the illumination intensity is increased too much for an object 50 containing materials with heat input limitations, the object 50 will deteriorate. In this embodiment, the illumination area for the object 50 is made to include multiple areas, thereby distributing the power of the illumination light between the first illumination light L11 and the second illumination light L12. Furthermore, throughput can be improved by positioning the detection means 30 to observe the positions corresponding to the illumination areas.

[0045] To improve throughput, it is possible to enlarge the detection means 30 to perform large-capacity data processing, but the physical size of the detection means 30 becomes a problem. In such cases, a method using multiple detection means, including the first detection means 31 and the second detection means 32, as in this embodiment, is effective.

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

[0047] The first elliptical mirror 21 illuminates the first region 51 of the object 50 with first critical illumination by first illumination light L11 generated from the first luminous beam of light from the first bright spot 11. The optical system 20a may interpose other elliptical mirrors or mirrors of other shapes 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 by first illumination light L11 generated from any first luminous beam of light from the first bright spot 11.

[0048] The second elliptical mirror 22 illuminates the second region 52 of the object 50 with second critical illumination by second illumination light L12 generated from the second luminous beam of light from the second bright spot 12. The optical system 20a can illuminate the second region 52 of the object 50 with second critical illumination by second illumination light L12 generated from any second luminous beam different from the first luminous beam of light from the second bright spot 12, and other elliptical mirrors or mirrors of other shapes besides the second elliptical mirror 22 may be interposed between the second bright spot 12 and the second region 52. The first and second luminous beams may be mutually exclusive, that is, none of the luminous beams included in the first luminous beam are included in the second luminous beam, and none of the luminous beams included in the second luminous beam are included in the first luminous beam.

[0049] The first elliptic mirror 21 may have one focal point at the position of the first bright spot 11. In this case, a mirror may be interposed to make the focal point of the first elliptic mirror 21 the position of the first bright spot 11 rather than the focal position of the first elliptic mirror 21. Such an example is also included in the first elliptic mirror 21 having one focal point at the position of the first bright spot 11. The first elliptic mirror 21 may have the other focal point at the position of the first region 51. In this case, a mirror may be interposed to make the other focal point of the first elliptic mirror 21 the position of the first region 51 rather than the other focal position of the first elliptic mirror 21. Such an example is also included in the first elliptic mirror 21 having the other focal point at the position of the first region 51. The second elliptic mirror 22 may have one focal point at the position of the second bright spot 12. In this case, a mirror may be interposed to make one of the focal points of the second elliptic mirror 22 the position of the second bright spot 12 rather than the focal position of the second elliptic mirror 22. Such an example is also included in the case where the second elliptic mirror 22 has one focal point at the position of the second bright spot 12. The second elliptic mirror 22 may have the other focal point at the position of the second region 52. In this case, a mirror may be interposed to make the other focal point of the second elliptic mirror 22 the position of the second region 52 rather than the focal position of the second elliptic mirror 22. Such an example is also included in the case where the second elliptic mirror 22 has the other focal point at the position of the second region 52. The first elliptic mirror 21 may have one focal point at the position of the first bright spot 11, or the other focal point at the position of the first region 51. The first elliptic mirror 21 may have one focal point at the position of the first bright spot 11 and the other focal point at the position of the first region 51. The second elliptical mirror 22 may have one focal point at the position of the second bright spot 12, or the other focal point at the position of the second region 52. The second elliptical mirror 22 may have one focal point at the position of the second bright spot 12 and the other focal point at the position of the second region 52. The first elliptical mirror 21 may have one focal point at the position of the first bright spot 11 and the other focal point at the position of the first region 51, while the second elliptical mirror 22 may have one focal point at the position of the second bright spot 12 and the other focal point at the position of the second region 52. With any of the above configurations, a minimum number of optical components can be used, and the optical loss of the first illumination light L11 and the second illumination light L12 due to the optical components can be reduced.Therefore, the optical system 20a illuminates the first region 51 of the object 50 with high luminosity in the first critical illumination by the first illumination light L11 generated from the first bright spot 11, and illuminates the second region 52 of the object 50 with high luminosity in the second critical illumination by the second illumination light L12 generated from the second bright spot 12.

[0050] In the optical system 20a, an optical aperture is not required in the optical paths of the first illumination light L11 and the second illumination light L12 from the first bright spot 11 and the second bright spot 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 the focal point of one of the first elliptical mirrors 21 and the second elliptical mirror 22 to the positions of the first bright spot 11 and the second bright spot 12, respectively, and aligning the focal point of the other to the first region 51 and the second region 52, respectively. Furthermore, the first illumination light L11 and the second illumination light L12 incident on the first elliptical mirror 21 and the second elliptical mirror 22 can efficiently illuminate the first region 51 and the second region 52, thereby improving inspection accuracy.

[0052] <Variation 1-2> Next, a modified example 2 of Embodiment 1 will be described. Figure 6 is a configuration diagram illustrating an inspection apparatus 1b according to a modified example 2 of Embodiment 1. As shown in Figure 6, in the inspection apparatus 1b, the optical system 20b further includes a switching means 29. The switching means 29 is attached, for example, to the second elliptical mirror 22. The switching means 29 can change the orientation of the reflective surface of the second elliptical mirror 22. As a result, the second illumination light L12, which was 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 called the first mode. The mode in which the first region 51 is illuminated with the second critical illumination is called the second mode. Thus, the switching means 29 has the function of switching between the first mode and the second mode.

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

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

[0055] The modified inspection device 1b is equipped with a switching means 29, which allows 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. Therefore, inspection conditions can be diversified.

[0056] <Embodiment 2> Figure 8 is a diagram illustrating the configuration of an inspection apparatus 2 according to Embodiment 2. As shown in Figure 8, in the inspection apparatus 2 of this embodiment, the optical system 20c includes a first elliptical mirror 21 and a second elliptical mirror 22 instead of a mirror 23. Furthermore, the inspection apparatus 2 of this embodiment does not necessarily have a plasma forming means 10 for forming 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 LR3. LR3 The formation is not limited to irradiation, but may also occur by discharging a target material 15 placed between electrodes.

[0057] The first elliptical mirror 21 illuminates the first region 51 of the object 50 with first critical illumination by first illumination light L11 generated from the bright spot 13. The optical system 20c can also interpose other elliptical mirrors or mirrors of other shapes between the bright spot 13 and the first region 51, 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 the bright spot 13.

[0058] The first elliptical mirror 21 may have one of its focal points at the position of the bright spot 13. In this case as well, the first elliptical mirror 21 illuminates the first region 51 of the object 50 with first critical illumination by first illumination light L11 generated from the bright spot 13. Note that in this case, one of the focal points of the first elliptical mirror 21 may be not one of the focal points of the first elliptical mirror 21. Bright spot 13 A mirror may be interposed to achieve the position. In such an example, one of the focal points of the first elliptical mirror 21 is Bright spot 13 It is included in the position.

[0059] The second elliptical mirror 22 may have one of its focal points at the position of the bright spot 13. In this case as well, the second elliptical mirror 22 illuminates the second region 52 of the object 50 with second critical illumination by second bright light L12 generated from the bright spot 13. Note that in this case, one of the focal points of the second elliptical mirror 22 may be not one of the focal points of the second elliptical mirror 22. Bright spot 13 A mirror may be interposed to achieve the position. In such an example, one of the focal points of the second elliptical mirror 22 is Bright spot 13 It is included in the position.

[0060] The first elliptic mirror 21 may have its other focal point at the position of the first region 51. The second elliptic mirror 22 may have its other focal 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 make the other focal point of the first elliptic mirror 21 at the position of the first region 51 instead of the other focal point of the first elliptic mirror, or a mirror may be interposed to make the other focal point of the second elliptic mirror 22 at the position of the second region 52 instead of the other focal point of the second elliptic mirror. Such examples are also included in the case where the other focal point of the first elliptic mirror 21 is at the position of the first region 51, and the other focal point of the second elliptic mirror 22 is at the position of the second region 52.

[0061] In this embodiment, no optical aperture is provided in 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] Figure 9 is a flowchart illustrating a control method for the inspection apparatus 2 according to Embodiment 2. As shown in Figure 9, the control method for the inspection apparatus 2 of this embodiment includes an illumination step S21 and a detection step S22. In the illumination step S21, the control unit 40 may cause a first elliptical mirror 21, which has one focusing point at the position of the bright spot 13 in the optical system 20c, to illuminate a first critical illumination with a first illumination light L11 generated from the bright spot 13. At the same time, the control unit 40 may cause a second elliptical mirror 22, which has one focusing point at the position of the bright spot 13 in the optical system 20c, to illuminate a second critical illumination with a second illumination light L12 generated from the bright spot 13. The detection step S22 is the same as 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 illumination light L11 and the second illumination light L12 incident on the first elliptical mirror 21 and the second elliptical mirror 22 can efficiently illuminate the first region 51 and the second region 52, thereby improving inspection accuracy.

[0064] <Variation 2-1> Next, a modification 1 of Embodiment 2 will be described. Figure 10 is a configuration diagram illustrating an inspection apparatus 2a according to modification 1 of Embodiment 2. As shown in Figure 10, in the inspection apparatus 2a, the optical system 20d further includes a switching means 29. The switching means 29 changes the orientation of the reflective surface of the second elliptical mirror 22, for example. As a result, the second illumination light L12, which was 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 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, as in the modification 2 of Embodiment 1 described above. Therefore, the switching means 29 has the function of switching between the first mode and the second mode.

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

[0066] Figure 11 is a flowchart illustrating a control method for an inspection device 2a according to a modified example 1 of Embodiment 2. As shown in Figure 11, the control method for the inspection device 2a further includes a switching step S20. In the switching step S20, the control unit 40 causes the switching means 29 to switch to a first mode in which the second area 52 is illuminated with the second critical illumination, or a second mode in which the first area 51 is illuminated with the second critical illumination. In Figure 11, the switching step S20 is performed before the illumination step S21, but this is not limited to that. 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, which allows 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. Therefore, inspection conditions can be diversified.

[0068] While embodiments of this disclosure have been described above, this disclosure includes appropriate modifications that do not impair its purpose and advantages, and is not limited by the embodiments described above. Furthermore, appropriate omissions and combinations of the components of Embodiments 1 and 2 and each of their modifications also fall within the scope of the technical concept of this 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 Miller 24 concave mirror 25 Mirror 26 holes 27, 28 Miller 29 Switching means 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 secondary light rays from an object illuminated by the critical illumination, Plasma forming means for forming at least a first bright spot and a second bright spot, Equipped with, The plasma forming means is By irradiating excitation light at different positions toward a target material in the same space, at least the first and second bright spots are formed. The optical system described above is The first region of the object is illuminated with first critical illumination using first illumination light generated from the first bright spot, The second critical illumination of the object, which is different from the first region, is illuminated by the second illumination light generated from the second bright spot. The detection means is A first detection means for detecting a first ray including the secondary ray from the object illuminated by the first critical illumination, A second detection means for detecting a second ray, including the secondary ray, from the object illuminated by 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 secondary light rays from an object illuminated by the critical illumination, Equipped with, The optical system described above is The first region of the object is illuminated with first critical illumination using first illumination light generated from the first luminous beam of light from the bright spot, The second region of the object, which is different from the first region, is illuminated by a second critical illumination light generated from a second luminous beam, which is different from the first luminous beam of light from the bright spot, The detection means is A first detection means for detecting a first ray including the secondary ray from the object illuminated by the first critical illumination, A second detection means for detecting a second ray, including the secondary ray, from the object illuminated by the second critical illumination, including, optical equipment.

3. The optical system is The first region is illuminated by a first critical illumination using a first illumination light generated from a first luminous beam of light from the bright spot via a first elliptical mirror. The second region is illuminated by a second critical illumination light, which is generated from a second luminous beam different from the first luminous beam of light from the bright spot, via a second elliptical mirror. The optical apparatus according to claim 2.

4. The optical system illuminates a first region of the object with the first critical illumination, and illuminates a second region of the object with the second critical illumination. The optical apparatus according to claim 1 or 2.

5. An optical system for illuminating an object with critical illumination using plasma as a bright spot, A detection means for detecting secondary light rays from an object illuminated by the critical illumination, Plasma forming means for forming at least a first bright spot and a second bright spot, Equipped with, The optical system described above is The first region of the object is illuminated with first critical illumination using first illumination light generated from the first bright spot, The second critical illumination of the object, which is different from the first region, is illuminated by the second illumination light generated from the second bright spot. The detection means is A first detection means for detecting a first ray including the secondary ray from the object illuminated by the first critical illumination, A second detection means for detecting a second ray, including the secondary ray, from the object illuminated by the second critical illumination, Includes, The optical system includes switching means for switching between a first mode in which the second region is illuminated by the second critical illumination, or a second mode in which the first region is illuminated by the second critical illumination. optical equipment.

6. The optical system includes switching means for switching between a first mode in which the second region is illuminated by the second critical illumination, or a second mode in which the first region is illuminated by the second critical illumination. The optical apparatus according to claim 2.

7. Viewed from the optical axis direction of the first and second rays, the first detection means and the second detection means are arranged alternately in a staggered pattern. The optical apparatus according to claim 1 or 2.

8. The optical system described above is A first elliptical mirror having one focusing point at the position of the first bright spot and the other focusing point at the position of the first region, A second elliptical mirror having one focal point at the position of the second bright spot and the other focal point at the position of the second region, including, The optical apparatus according to claim 1.

9. The first elliptical mirror has one focal point at the position of the bright spot and the other focal point at the position of the first region. The second elliptical mirror has one focal point at the position of the bright spot and the other focal point at the position of the second region. The optical apparatus according to claim 3.

10. An optical system for illuminating an object with critical illumination using plasma as a bright spot, A detection means for detecting secondary light rays from an object illuminated by the critical illumination, Plasma forming means for forming at least a first bright spot and a second bright spot, Equipped with, The optical system described above is The first region of the object is illuminated with first critical illumination using first illumination light generated from the first bright spot, The second critical illumination of the object, which is different from the first region, is illuminated by the second illumination light generated from the second bright spot. The detection means is A first detection means for detecting a first ray including the secondary ray from the object illuminated by the first critical illumination, A second detection means for detecting a second ray, including the secondary ray, from the object illuminated by the second critical illumination, Includes, The optical system described above is A first elliptical mirror having one focusing point at the position of the first bright spot and the other focusing point at the position of the first region, A second elliptical mirror having one focal point at the position of the second bright spot and the other focal point at the position of the second region, Includes, No aperture is provided in the optical paths of the first illumination light and the second illumination light from the bright spot to the object. optical equipment.

11. No aperture is provided in the optical paths of the first illumination light and the second illumination light from the bright spot to the object, The optical apparatus according to claim 2.

12. No aperture is provided in the optical paths of the first illumination light and the second illumination light from the bright spot to the object. The optical apparatus according to claim 9.

13. An optical system that illuminates an object with critical illumination using plasma as a bright spot, A detection means for detecting secondary light rays from an object illuminated by the critical illumination, Plasma forming means for forming at least a first bright spot and a second bright spot, A control method for an optical device comprising, The plasma forming means includes a bright spot formation step in which at least the first and second bright spots are formed as bright spots by irradiating excitation light at different positions toward a target material in the same space, The optical system includes an illumination step in which a first region of the object is illuminated by a first critical illumination using a first illumination light generated from the first bright spot, and a second region of the object, different from the first region, is illuminated by a second critical illumination using a second illumination light generated from the second bright spot. A detection step in which the first detection means in the detection means detects a first ray including the secondary ray from the object illuminated by the first critical illumination, and the second detection means in the detection means detects a second ray including the secondary ray from the object illuminated by the second critical illumination, A method for controlling an optical device equipped with such a device.

14. An optical system that illuminates an object with critical illumination using plasma as a bright spot, A detection means for detecting secondary light rays from an object illuminated by the critical illumination, A control method for an optical device comprising, The illumination step involves illuminating a first region of the object with a first critical illumination using a first illumination light generated from a first luminous beam of light from the bright spot, and illuminating a second region of the object, different from the first region, with a second critical illumination using a second illumination light generated from a second luminous beam different from the first luminous beam of light from the bright spot. A detection step in which the first detection means in the detection means detects a first ray including the secondary ray from the object illuminated by the first critical illumination, and the second detection means in the detection means detects a second ray including the secondary ray from the object illuminated by the second critical illumination, A method for controlling an optical device equipped with such a device.

15. In the lighting step, The first region of the object is illuminated by a first critical illumination using a first illumination light generated from a first luminous beam of light from the bright spot via a first elliptical mirror in the optical system, and the second region of the object, which is different from the first region, is illuminated by a second critical illumination using a second illumination light generated from a second luminous beam of light different from the first luminous beam of light from the bright spot via a second elliptical mirror in the optical system. A method for controlling an optical device according to claim 14.

16. In the aforementioned lighting step, The optical system is configured such that when the first critical illumination illuminates the first region of the object, the second critical illumination illuminates the second region of the object. A method for controlling an optical device according to claim 13 or 14.

17. An optical system for illuminating an object with critical illumination using plasma as a bright spot, A detection means for detecting secondary light rays from an object illuminated by the critical illumination, Plasma forming means for forming at least a first bright spot and a second bright spot, A control method for an optical device comprising, The plasma forming means is used to form at least a first bright spot and a second bright spot, The optical system includes an illumination step in which a first region of the object is illuminated by a first critical illumination using a first illumination light generated from the first bright spot, and a second region of the object, different from the first region, is illuminated by a second critical illumination using a second illumination light generated from the second bright spot. A detection step in which the first detection means in the detection means detects a first ray including the secondary ray from the object illuminated by the first critical illumination, and the second detection means in the detection means detects a second ray including the secondary ray from the object illuminated by the second critical illumination, Equipped with, The switching means further includes a switching step that switches to a first mode in which the second area is illuminated with the second critical illumination, or a second mode in which the first area is illuminated with the second critical illumination. A method for controlling optical devices.

18. The switching means further includes a switching step that switches to a first mode in which the second area is illuminated with the second critical illumination, or a second mode in which the first area is illuminated with the second critical illumination. A method for controlling an optical device according to claim 14.

19. Viewed from the optical axis direction of the first and second rays, the first detection means and the second detection means are arranged alternately in a staggered pattern. A method for controlling an optical device according to claim 13 or 14.

20. In the aforementioned lighting step, The first region is illuminated with a first elliptical mirror having one focusing point at the position of the first bright spot and the other focusing point at the position of the first region. The second region is illuminated with a second elliptical mirror having one focusing point at the position of the second bright spot and the other focusing point at the position of the second region. A method for controlling an optical device according to claim 13.

21. In the aforementioned lighting step, The first elliptical mirror has one focal point at the position of the bright spot and the other focal point at the position of the first region. The second elliptical mirror has one focal point at the position of the bright spot and the other focal point at the position of the second region. A method for controlling an optical device according to claim 15.

22. An optical system for illuminating an object with critical illumination using plasma as a bright spot, A detection means for detecting secondary light rays from an object illuminated by the critical illumination, Plasma forming means for forming at least a first bright spot and a second bright spot, A control method for an optical device comprising, The plasma forming means is used to form at least a first bright spot and a second bright spot, The optical system includes an illumination step in which a first region of the object is illuminated by a first critical illumination using a first illumination light generated from the first bright spot, and a second region of the object, different from the first region, is illuminated by a second critical illumination using a second illumination light generated from the second bright spot. A detection step in which the first detection means in the detection means detects a first ray including the secondary ray from the object illuminated by the first critical illumination, and the second detection means in the detection means detects a second ray including the secondary ray from the object illuminated by the second critical illumination, Equipped with, In the aforementioned lighting step, The first region is illuminated with a first elliptical mirror having one focusing point at the position of the first bright spot and the other focusing point at the position of the first region. The second region is illuminated with a second elliptical mirror having one focusing point at the position of the second bright spot and the other focusing point at the position of the second region. In the aforementioned lighting step, No aperture is provided in the optical paths of the first illumination light and the second illumination light from the bright spot to the object. A method for controlling optical devices.

23. In the lighting step, No aperture is provided in the optical paths of the first illumination light and the second illumination light from the bright spot to the object. A method for controlling an optical device according to claim 14.

24. In the lighting step, No aperture is provided in the optical paths of the first illumination light and the second illumination light from the bright spot to the object. A method for controlling an optical device according to claim 21.

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