Light-irradiation apparatus, measurement apparatus, and charged particle beam apparatus

Abstract

This light-irradiation apparatus comprises: a first optical device that includes a first light source capable of emitting first light having a first wavelength, a detection element that detects reflected light obtained when a sample is irradiated with the first light, and an optical filter disposed on the midway of an optical path connecting the sample and the detection element; and a second optical device that includes a second light source capable of emitting second light having a second wavelength different from the first wavelength and a harmonic generation crystal capable of converting the second light into third light having a third wavelength shorter than the second wavelength, and that is capable of irradiating the sample with one or both of the second light and the third light. The third wavelength is different from the first wavelength. The optical filter can block the light of each of the second wavelength and the third wavelength, and cause the light of the first wavelength to pass therethrough.

Description

Light irradiation device, measurement device, and charged particle beam device

[0001] The present invention relates to a light irradiation device, a measurement device including a light irradiation device, and a charged particle beam device including a light irradiation device.

[0002] Patent Document 1 (JP 2021-039844 A) describes a method for changing the signal amount of secondary charged particles emitted from a sample by irradiating the sample with light under multiple light irradiation conditions in a charged particle beam device.

[0003] Patent Document 2 (JP 2007-132836 A) describes a method for measuring the height of an object to be measured by irradiating the object with light and detecting the light reflected by the object in an electron beam device.

[0004] JP 2021-039844 A JP 2007-132836 A

[0005] A light irradiation device that irradiates a sample with light can be used to measure various values, such as the position, material, thickness, or shape of the sample. Furthermore, as described in Patent Document 1, in a charged particle beam device, light may be irradiated onto the sample in order to change the signal amount of secondary charged particles. From the viewpoint of improving the accuracy of measurement results or increasing the efficiency of measurement work, it may be preferable to simultaneously irradiate the sample with multiple types of light when measuring the sample using a light irradiation device.

[0006] However, when a sample is irradiated with multiple types of light, scattered light generated when light of a certain wavelength is irradiated onto the sample may become noise in other measurement items, resulting in reduced measurement accuracy.

[0007] Other objects and novel features will become apparent from the description of this specification and the accompanying drawings.

[0008] A light irradiation device according to one embodiment includes a first optical device including a first light source capable of irradiating first light having a first wavelength, a detection element for detecting reflected light obtained when the first light is irradiated onto a sample, and an optical filter disposed along an optical path connecting the sample and the detection element; a second optical device including a second light source capable of irradiating second light having a second wavelength different from the first wavelength and a harmonic generation crystal capable of converting the second light into third light having a third wavelength shorter than the second wavelength, and capable of irradiating the sample with one or both of the second light and the third light. The third wavelength is different from the first wavelength. The optical filter is capable of blocking light of the second wavelength and the third wavelength and transmitting light of the first wavelength.

[0009] Another embodiment of the light irradiation device includes a first optical device including a first light source capable of irradiating first light having a first wavelength band, a detection element for detecting reflected light obtained when the first light is irradiated onto a sample, and a plurality of optical filters that can be arranged along an optical path connecting the sample and the detection element; a second optical device including a second light source capable of irradiating second light; and one or more computer systems that can select an optical filter from the plurality of optical filters to be arranged along the optical path connecting the sample and the detection element in accordance with the wavelength of the second light irradiated by the second optical device toward the sample. The second light source is a wavelength-tunable light source that can change the wavelength of the second light in a wavelength band that includes the first wavelength band. The first optical device includes an optical filter switching mechanism that can arrange an optical filter selected from the plurality of optical filters along the optical path connecting the sample and the detection element based on a control signal output by the one or more computer systems. Each of the plurality of optical filters is capable of passing a portion of the first wavelength band. An optical filter selected by the one or more computer systems and placed in the optical path connecting the sample and the detection element by the optical filter switching mechanism is capable of blocking the second light.

[0010] Another embodiment of the light irradiation device includes a first optical device including a first light source capable of irradiating a sample with light of different wavelengths, the first light source capable of irradiating a first light from any of the light source elements, a detection element for detecting reflected light obtained when the first light is irradiated onto a sample, and a plurality of optical filters that can be arranged along an optical path connecting the sample and the detection element, a second optical device including a second light source capable of irradiating a second light, and one or more computer systems that can select an optical filter from the plurality of optical filters to be arranged along the optical path connecting the sample and the detection element based on the wavelength of the first light irradiated from the first light source and the wavelength of the second light irradiated toward the sample by the second optical device. The second light source is a wavelength-tunable light source that can change the wavelength of the second light. The first optical device includes an optical filter switching mechanism that can arrange an optical filter selected from the plurality of optical filters along the optical path connecting the sample and the detection element based on a control signal output by the one or more computer systems. An optical filter selected by the one or more computer systems and placed in the optical path connecting the sample and the detection element by the optical filter switching mechanism is capable of blocking the second light.

[0011] According to the above embodiment, the performance of the light irradiation device can be improved.

[0012] 7 is an explanatory diagram showing an example of the configuration of a charged particle beam device according to an embodiment. FIG. 7 is an explanatory diagram showing a portion of the charged particle beam device shown in FIG. 1 that corresponds to a light irradiation device. FIG. 7 is an explanatory diagram showing a portion of the charged particle beam device shown in FIG. 1 that corresponds to an optical measurement device. FIG. 7 is an explanatory diagram showing an example of the spectral characteristics of an optical filter arranged between a detection element and a sample in FIG. 1. FIG. 7 is an explanatory diagram showing an example of the configuration of an optical measurement device that is a modification of FIG. 3. FIG. 7 is an explanatory diagram showing an example of the configuration of an optical measurement device that is a modification of FIG. 5. FIG. 7 is an explanatory diagram showing an example of the configuration of an optical measurement device that is another modification of FIG. 3. FIG. 7 is an explanatory diagram showing an example of the spectral characteristics of one optical filter out of the plurality of optical filters shown in FIG. 7. FIG. 7 is an explanatory diagram showing an example of the spectral characteristics of the other optical filter out of the plurality of optical filters shown in FIG. 7. FIG. 7 is an explanatory diagram showing a range of a wavelength band of light that can be output by the wavelength-tunable light source shown in FIG. 7. FIG. 7 is an explanatory diagram showing a modification of the wavelength-tunable laser light irradiation device shown in FIG. 7. FIG. 7 is an explanatory diagram showing an example of the configuration of an optical measurement device that is a modification of FIG. 7. FIG. 7 is an explanatory diagram showing an example of the wavelength band of light that can be output by the wavelength-tunable light source shown in FIG. 12 and an example of the wavelength range of light emitted from the light source for the measurement device shown in FIG.

[0013] (Explanation of description format, basic terms, and usage in this application) Hereinafter, embodiments will be described in detail with reference to the drawings. In all drawings used to explain the embodiments, components having the same functions are designated by the same reference numerals, and repeated explanations thereof will be omitted. In addition, in the following embodiments, explanations of the same or similar parts will not be repeated unless particularly necessary.

[0014] The light irradiation device is a device that includes at least one light source that irradiates light. The light irradiation device may include multiple light sources. The light irradiation device may include a wavelength converter that converts the wavelength of light emitted from the light source. The light irradiation device may include a detection element that detects light. The light irradiation device may include an optical filter that selectively passes a portion of the light incident on the detection element.

[0015] An optical measurement device or a metrology device is a device capable of measuring physical quantities of a sample. This specification describes an optical measurement device including a light irradiation device. The optical measurement device may include one or more computer systems that measure (calculate) the physical quantities of the sample based on the output signal of the detection element. The computer system may also be capable of performing various controls, such as controlling the operation of one or more light sources, controlling the switching operation of optical filters, or controlling the position of the sample.

[0016] A charged particle beam device is a device capable of irradiating a sample with a primary charged particle beam and detecting secondary charged particles obtained by irradiating the sample with the primary charged particle beam. This specification describes a charged particle beam device including a light irradiation device. The charged particle beam device may include one or more computer systems that generate images based on the detection results of the secondary charged particles. The charged particle beam device may include the light irradiation device described above or the measurement device described above.

[0017] The light irradiation device, optical measurement device, and charged particle beam device described below each include one or more computer systems for control, measurement, or calculation. In the following, an example will be described in which a separate computer system is provided for each function of the computer system, but there are also cases in which a single computer system performs multiple functions described below.

[0018] <Charged particle beam device, light irradiation device, and optical measurement device> Fig. 1 is an explanatory diagram showing an example of the configuration of a charged particle beam device according to one embodiment. Fig. 2 is an explanatory diagram showing a portion of the charged particle beam device shown in Fig. 1 that corresponds to the light irradiation device. Fig. 3 is an explanatory diagram showing a portion of the charged particle beam device shown in Fig. 1 that corresponds to the optical measurement device. Fig. 4 is an explanatory diagram showing an example of the spectral characteristics of an optical filter arranged between the detection element and the sample in Fig. 1.

[0019] 1 includes an electron optical device (electro-optical system) 10, a sample support device (sample support system) 20, a measurement device (optical measurement device) 30, and a wavelength-tunable laser light irradiation device (wavelength-tunable laser light irradiation system, optical device) 40. As shown in FIG. 2, a light irradiation device 200 included in the charged particle beam device 100 includes a part of the measurement device 30 and the wavelength-tunable laser light irradiation device 40.

[0020] The electron optical device 10 is a device capable of detecting secondary charged particles obtained by irradiating an electron beam (primary charged particle beam) onto a sample 2. The electron optical device 10 includes an electron gun 11, a deflector 12, a secondary electron detector 13, and an electron lens 14. In the present embodiment, the electron optical device 10 is a device capable of measuring (determining) the shape or material of the sample 2 by irradiating the sample 2 with an electron beam while irradiating it with light from a wavelength-tunable laser light irradiation device 40.

[0021] The electron beam accelerated by the electron gun 11 is focused by the electron lens 14 and irradiated onto the sample 2. The deflector 12 controls the irradiation position of the electron beam on the sample 2. The secondary electron detector 13 detects secondary electrons (secondary charged particles) emitted from the sample 2 when the electron beam is irradiated onto the sample 2.

[0022] The sample support device 20 includes a sample holding mechanism that holds the sample 2 and a drive mechanism that moves the sample 2 to an appropriate position. The sample support device 20 includes a sample holder 21 that holds the sample 2, a sample stage 22 that supports the sample holder 21, and a stage drive mechanism 23 that drives the sample stage 22. The sample stage 22 supports the sample 2 via the sample holder 21. Note that although the sample support device 20 shown in FIG. 1 is not shown in FIGS. 2 and 3, the sample support device 20 can be part of the light irradiation device 200 shown in FIG. 2 or part of the optical measurement device 300 shown in FIG. 3.

[0023] The measurement device 30 is an optical sample measurement device capable of optically measuring the physical quantities of the sample 2. In the present embodiment, the measurement device 30 has a function of optically measuring, for example, the height of the sample 2 (for example, the height of the sample 2 when the upper surface of the sample stage 22 is taken as the reference plane). The measurement device 30 includes a light source 31, a light source-side lens 33, a detection-side lens 34, an optical filter 35, a detection element 36, and a computer system 37.

[0024] Light 31L emitted from a light source 31 of the measurement device 30 passes through a light source-side lens 33 and forms an image on the surface of the sample 2. The light 31L is reflected from the surface of the sample 2, passes through a detection-side lens 34 and an optical filter 35, and forms an image again on the surface of a detection element 36. An output signal from the detection element 36 is transmitted to a computer system 37. In this embodiment, the computer system 37 is electrically connected to the detection element 36 and is a height calculation processor that is capable of measuring (calculating) the height of the sample 2 based on the output signal from the detection element 36.

[0025] The tunable laser beam irradiating device 40 is an apparatus capable of generating a laser beam 44 and irradiating the sample 2 with the laser beam 44. The tunable laser beam irradiating device 40 includes a light control unit (computer system) 41, a light source 42, and a harmonic generator 43. The light control unit 41 is a computer system capable of controlling the conditions of the laser beam 44L output from the light source 42. In the present embodiment, the light source 42 is a tunable light source capable of changing the wavelength of the emitted light. The tunable laser beam irradiating device 40 is a tunable laser beam irradiating device equipped with the light source 42, which is a tunable light source.

[0026] In this embodiment, the wavelength-variable laser light irradiation device 40 is used for the purpose of changing the signal amount of secondary electrons obtained when a primary charged particle beam is irradiated onto the sample 2 from the electron gun of the electron optical device 10.

[0027] When the sample 2 is irradiated with the primary charged particle beam while being irradiated with the laser beam 44, the signal amount (emission amount) of the secondary charged particles changes compared to when the sample 2 is not irradiated with the laser beam 44. For example, when the surface of the sample 2 is made of silicon (Si), by controlling the irradiation conditions (wavelength, etc.) of the laser beam 44, the signal amount (emission amount) of the secondary charged particles can be more than doubled compared to when the sample 2 is not irradiated with the laser beam 44. Furthermore, when the surface of the sample 2 is made of silicon oxide (SiO2), by controlling the irradiation conditions (wavelength, etc.) of the laser beam 44, the signal amount (emission amount) of the secondary charged particles can be increased to about 0.7 times compared to when the sample 2 is not irradiated with the laser beam 44.

[0028] This phenomenon occurs because the absorption coefficient of light (laser light 44) differs depending on the irradiated material. There is a correlation between the absorption coefficient of light and the amount of secondary electrons emitted, and as the absorption coefficient of light increases, the amount of secondary electrons emitted also increases.

[0029] Furthermore, the light absorption coefficient varies depending on the wavelength of the laser light 44. Therefore, the amount of secondary electrons emitted varies depending on the wavelength of the laser light 44. By utilizing this characteristic, when a primary charged particle beam is irradiated onto the sample 2 while multiple laser lights 44 with different irradiation conditions are irradiated onto the sample 2 in sequence, the signal amounts (emission amounts) of the secondary electrons will differ from each other. Therefore, it is possible to determine the material or shape present in the illuminated region of the sample 2 based on the signal amount of the secondary electrons detected by the secondary electron detector 13 of the electron optical device 10.

[0030] Since the physical phenomena that can occur in the short wavelength band and the long wavelength band are different, the amount of secondary electrons can be controlled according to any (desired) physical phenomenon by selecting the wavelength according to the material. For example, in the case of this embodiment, two wavelength bands, a long wavelength band (e.g., visible light to near-infrared light with long wavelengths) and a short wavelength band (e.g., visible light to ultraviolet light with short wavelengths) are used as the laser light 44 to be irradiated onto the sample 2.

[0031] The light source 42 can emit, for example, a wavelength-tunable laser beam in a long wavelength band. The harmonic generator 43 is an optical device including a crystal for generating harmonics, such as SHG (Second Harmonic Generation), THG (Third Harmonic Generation), or FHG (Fourth Harmonic Generation). The harmonic generator 43 can convert a long wavelength laser beam into a short wavelength laser beam. Therefore, when irradiating the sample 2 with a long wavelength laser beam 44, the laser beam 44L emitted from the light source 42 is irradiated as the laser beam 44 along an optical path that does not pass through the harmonic generator 43. On the other hand, when using a short wavelength laser beam, the laser beam 44L emitted from the light source 42 is converted into a short wavelength laser beam 44S in the harmonic generator 43 and is irradiated as the laser beam 44 onto the sample 2.

[0032] In the present embodiment, the tunable laser beam irradiating device 40 is used auxiliary to measure (determine) the sample 2 using the electron optical device 10, and therefore, irradiation of the laser beam 44 by the tunable laser beam irradiating device 40 and irradiation of the primary charged particle beam by the electron optical device 10 need to be carried out simultaneously. Furthermore, since the height of the sample 2 may change over time, it is preferable that irradiation of the light 31L by the measuring device 30 and irradiation of the primary charged particle beam by the electron optical device 10 are carried out simultaneously. Therefore, irradiation of the laser beam 44 by the tunable laser beam irradiating device 40 and irradiation of the light 31L by the measuring device 30 are carried out simultaneously.

[0033] As shown in FIG. 1 , when the sample 2 is irradiated with laser light 44, multiple scattered lights 45 of the wavelength-tunable laser are generated depending on the structure of the surface (irradiated surface) of the sample 2. Some of the multiple scattered lights 45 may travel toward the detecting element 36 of the measurement device 30. When the scattered light 45 enters the detecting element 36 of the measurement device 30, the detecting element 36 detects the scattered light 45 in addition to the light 31L. In the signal transmitted to the computer system 37, the component caused by the scattered light 45 is noise. Therefore, when the scattered light 45 enters the detecting element 36, it causes a decrease in the measurement accuracy of the measurement device 30. Furthermore, depending on the level of the component caused by the scattered light 45, measurement by the measurement device 30 may be impossible.

[0034] The light irradiation device 200 shown in FIG. 2 (the optical measurement device 300 shown in FIG. 3 and the charged particle beam device 100 shown in FIG. 1) has the following configuration, thereby preventing scattered light 45 from entering the detection element 36.

[0035] That is, the light irradiation device 200 (the optical measurement device 300 shown in FIG. 3 and the charged particle beam device 100 shown in FIG. 1) includes a measurement device (optical device) 30 and a wavelength-tunable laser light irradiation device (optical device) 40. The measurement device 30 includes a light source 31 capable of irradiating light 31L having a certain wavelength, a detection element 36 that detects reflected light obtained when the light 31L is irradiated onto the sample 2, and an optical filter 35 that is arranged midway along the optical path connecting the sample 2 and the detection element 36.

[0036] The wavelength-tunable laser beam irradiator 40 includes a light source 42 capable of irradiating light (laser beam 44L) having a wavelength different from that of the light 31L, and a harmonic generator 43 capable of converting part of the laser beam 44L into light (laser beam 44S) having a wavelength shorter than that of the laser beam 44L, and is capable of irradiating one or both of the laser beam 44L and the laser beam 44S onto the sample 2. The wavelengths of the laser beam 44S and the laser beam 44L are different from that of the light 31L. The optical filter 35 is capable of blocking the wavelengths of the laser beam 44S and the laser beam 44L, and of transmitting the wavelength of the light 31L.

[0037] Optical filter 35 has the property of reflecting or absorbing (blocking) light having the wavelength of laser light 44S and the wavelength of laser light 44L. Scattered light 45 shown in Figures 1 to 3 is light having the wavelength of laser light 44S or the wavelength of laser light 44L. Therefore, optical filter 35 can block and filter scattered light 45, thereby preventing scattered light 45 from entering detection element 36.

[0038] The optical path connecting the sample 2 and the detecting element 36 can be expressed in detail as follows. That is, the optical path is an optical path that travels toward the detecting element 36 in a straight line or by refraction or reflection, among multiple optical paths of scattered light 45 generated when the laser light 44 is irradiated onto the sample 2. Alternatively, as will be described later with reference to Figure 6, the optical path may be an optical path along which transmitted light (transmitted light 46 shown in Figure 6) generated when the laser light 44 is irradiated onto the sample 2 and a part of the light passes through the sample 2 travels toward the detecting element 36 in a straight line or by refraction or reflection.

[0039] On the other hand, the optical filter 35 has the property of passing light of the wavelength of the light 31L. Therefore, even if the optical filter 35 is disposed in the optical path connecting the sample 2 and the detecting element 36 (more specifically, the optical path of the reflected light of the light 31L), the reflected light of the light 31L reflected by the sample 2 passes through the optical filter 35 and is detected by the detecting element 36. As a result, the signal output from the detecting element 36 to the computer system 37 has components resulting from the scattered light 45, which are noise components, removed in advance.

[0040] Figure 4 is an explanatory diagram showing an example of the spectral characteristics of an optical filter disposed between the detection element and the sample in Figure 1. The optical filter 35 (see Figure 1) having the spectral characteristics shown in Figure 4 blocks (absorbs) light in the wavelength band (long wavelength band) λ2 and light in the wavelength band (short wavelength band) λ3. On the other hand, the optical filter 35 passes light in the wavelength band (intermediate wavelength band) λ1 between the wavelength bands λ2 and λ3. Therefore, the optical filter 35 functions as an optical filter for selectively passing light in the wavelength band λ1.

[0041] In the example of the spectral characteristics of the optical filter shown in Fig. 4, the wavelength of light 31L shown in Figs. 1 to 3 is included in the wavelength band λ1 (intermediate wavelength band) shown in Fig. 4. The wavelength of laser light 44L shown in Figs. 1 to 3 is included in the wavelength band λ2 (long wavelength band) shown in Fig. 4. The wavelength of laser light 44S (short wavelength band) shown in Figs. 1 to 3 is included in the wavelength band λ3 shown in Fig. 4. Therefore, scattered light 45 (see Fig. 1) that is scattered light of laser light 44L or laser light 44S is blocked by optical filter 35. On the other hand, light 31L passes through optical filter 35, so that detection element 36 can selectively receive reflected light of light 31L.

[0042] In the case of this embodiment, in the measuring device 30 which is a height measuring device, scattered light 45 of the laser light 44, which is a noise component, can be prevented from entering the detecting element 36. As a result, the measurement accuracy of the measuring device 30 can be improved.

[0043] In the present embodiment, of the wavelengths of laser beam 44L, laser beam 44S, and light 31L, the wavelength of light 31L is shorter than the wavelength of laser beam 44L and longer than the wavelength of laser beam 44S. In other words, the wavelength of laser beam 44L is longer than the wavelength of light 31L, and the wavelength of laser beam 44S is shorter than the wavelength of light 31L. In this case, the difference between the wavelengths of laser beam 44L and laser beam 44S can be set large.

[0044] Note that the wavelengths of the laser light 44L, the laser light 44S, and the light 31L may each be light having a single wavelength (monochromatic light) or light that can be separated into multiple spectra (in other words, polychromatic light having multiple wavelengths). Even when any of the wavelengths of the laser light 44L, the laser light 44S, and the light 31L is polychromatic light, the wavelength band of the polychromatic light is polychromatic light that corresponds to any one of the wavelength bands λ1, λ2, and λ3 shown in FIG. 4.

[0045] <Modification 1> Next, modifications of the charged particle beam device 100, light irradiation device 200, and optical measurement device 300 described using Figures 1 to 4 will be described. Figure 5 is an explanatory diagram showing an example of the configuration of an optical measurement device that is a modification of Figure 3. In the configuration example shown in Figure 5, the configuration obtained by removing the computer system 37A corresponds to the light irradiation device 200A of this modification. In addition, in the configuration example shown in Figure 5, the configuration obtained by adding the electron optical device 10 shown in Figure 1 corresponds to the charged particle beam device 100A of this modification.

[0046] The measurement device 30A shown in Fig. 5 differs from the measurement device 30 shown in Fig. 3 in that it is a device that optically measures the presence or absence of a sample 2. The measurement device 30A includes a light source 31A as a light projector, a detection element 36A as a light receiver, and an optical filter 35A that is disposed midway along the optical path connecting the sample 2 and the detection element 36A. The measurement device 30A also includes a computer system 37A that is electrically connected to the detection element 36A and is capable of measuring (detecting) the presence or absence of the sample 2 based on an output signal from the detection element 36A.

[0047] In this modified example, the presence or absence of the sample 2 on the sample stage 22 is measured, and therefore the light source 31A and the detection element 36A are each disposed above the sample stage 22. Light 31L emitted from the light source 31A is reflected by the object to be irradiated (the sample 2 in the example shown in FIG. 5 ) and enters the detection element 36A via the optical filter 35A. Although not shown, if light 31L is irradiated when the sample 2 is not placed, the light 31L is reflected by the surface of the sample holder 21 or the sample stage 22. The light reflected by the surface of the sample holder 21 or the sample stage 22 enters the detection element 36A via the optical filter 35A.

[0048] The detecting element 36A receives the reflected light of the light 31L and outputs a signal corresponding to the received light to the computer system 37A. The computer system 37A has a memory 37M. The memory 37M stores reference data for when the light 31L is reflected by the sample 2 and reference data for when the light 31L is reflected by the surface of the sample holder 21 or the sample stage 22. The computer system 37A compares the signal data received from the detecting element 36A with the reference data stored in the memory 37M to determine whether the sample 2 is placed on the sample stage 22.

[0049] 3 , in the case of the measurement device 30A of this modification, when the detection element 36A receives the reflected light of the light 31L, if a portion of the scattered light 45 of the laser light 44 enters the detection element 36A, the component caused by the scattered light 45 will be noise in the signal transmitted to the computer system 37A. Therefore, if the scattered light 45 enters the detection element 36A, it will cause a decrease in the measurement accuracy of the measurement device 30A. Furthermore, depending on the level of the component caused by the scattered light 45, it may become impossible for the measurement device 30A to perform measurement.

[0050] Therefore, the optical measuring device 300A (light irradiation device 200A or charged particle beam device 100A, hereinafter the same in this modified example) in this modified example has the following configuration, thereby preventing scattered light 45 from entering the detection element 36A.

[0051] That is, the optical measurement device 300A includes a measurement device (optical device) 30A and a wavelength-tunable laser light irradiation device (optical device) 40. The measurement device 30A includes a light source 31 capable of irradiating light 31L having a certain wavelength, a detection element 36A that detects reflected light obtained when the light 31L is irradiated onto the sample 2, and an optical filter 35A that is arranged midway along the optical path connecting the sample 2 and the detection element 36A.

[0052] As described above, in the case of the measuring device 30A, since the presence or absence of the sample 2 is measured, there are cases in which the sample 2 is not placed on the sample stage 22. When the sample 2 is not placed, the above-mentioned term "the optical path connecting the sample 2 and the detecting element 36A" can be read as "the optical path connecting the sample holder 21 or the sample stage 22 and the detecting element 36A."

[0053] The optical filter 35A has the property of reflecting or absorbing (blocking) light having the wavelengths of the laser light 44S and the laser light 44L. Therefore, the optical filter 35 can block and filter the scattered light 45, thereby preventing the scattered light 45 from entering the detection element 36.

[0054] On the other hand, the optical filter 35A has the property of passing light of the wavelength of the light 31L. Therefore, even if the optical filter 35A is disposed in the optical path connecting the sample 2 and the detecting element 36A (more specifically, the optical path of the reflected light of the light 31L), the reflected light of the light 31L reflected by the sample 2 (or the sample holder 21, or the sample stage 22) passes through the optical filter 35A and is detected by the detecting element 36A. As a result, the signal output from the detecting element 36A to the computer system 37A has components resulting from the scattered light 45, which is a noise component, removed in advance.

[0055] The explanation given using FIG. 4 can be similarly applied to the optical measurement device 300A shown in FIG. 5, so a duplicated explanation will be omitted.

[0056] Except for the above-mentioned differences, the optical measurement device 300A shown in Fig. 5 is similar to the optical measurement device 300 shown in Fig. 3. Therefore, a duplicated description will be omitted.

[0057] 5 can be used as a device that optically measures the presence or absence of the sample stage 22. In this case, the measurement device 30A includes a light source 31A as a light projector, a detection element 36A as a light receiver, an optical filter 35A arranged in the middle of the optical path connecting the sample 2 and the detection element 36A, and a reflector 22R provided on the sample stage 22. The measurement device 30A also includes a computer system 37A that is electrically connected to the detection element 36A and is capable of measuring (detecting) the presence or absence of the sample stage 22 based on the output signal of the detection element 36A.

[0058] When measuring the presence or absence of the sample stage 22, the light source 31A and the detection element 36A are each disposed above the sample stage 22. Light 31L emitted from the light source 31A is reflected by a reflector 22R provided on the sample stage 22, passes through an optical filter 35A, and enters the detection element 36A.

[0059] The detection element 36A receives the reflected light of the light 31L and outputs a signal corresponding to the received light to the computer system 37A. The computer system 37A has a memory 37M. The memory 37M stores information for determining whether the sample stage 22 is positioned or not based on whether the signal amount when the light 31L is reflected by the reflector 22R provided on the sample stage 22 exceeds a set threshold.

[0060] 3 , in the case of the measurement device 30A of this modification, when the detection element 36A receives the reflected light of the light 31L, if a portion of the scattered light 45 of the laser light 44 enters the detection element 36A, the component caused by the scattered light 45 will be noise in the signal transmitted to the computer system 37A. Therefore, if the scattered light 45 enters the detection element 36A, it will cause a decrease in the measurement accuracy of the measurement device 30A. Furthermore, depending on the level of the component caused by the scattered light 45, it may become impossible for the measurement device 30A to perform measurement.

[0061] Therefore, the optical measuring device 300A (light irradiation device 200A or charged particle beam device 100A, hereinafter the same in this modified example) in this modified example has the following configuration, thereby preventing scattered light 45 from entering the detection element 36A.

[0062] That is, the optical measurement device 300A includes a measurement device (optical device) 30A and a wavelength-tunable laser light irradiation device (optical device) 40. The measurement device 30A includes a light source 31 capable of irradiating light 31L having a certain wavelength, a reflector 22R provided on the sample stage 22, a detection element 36A that detects reflected light obtained when the light 31L is irradiated onto the reflector 22R provided on the sample stage 22, and an optical filter 35A that is arranged midway along the optical path connecting the reflector 22R provided on the sample stage 22 and the detection element 36A.

[0063] The optical filter 35A has the property of reflecting or absorbing (blocking) light having the wavelengths of the laser light 44S and the laser light 44L. Therefore, the optical filter 35 can block and filter the scattered light 45, thereby preventing the scattered light 45 from entering the detection element 36.

[0064] On the other hand, the optical filter 35A has the property of passing light of the wavelength of the light 31L. Therefore, even if the optical filter 35A is disposed in the optical path connecting the reflector 22R provided on the sample stage 22 and the detecting element 36A (more specifically, the optical path of the reflected light of the light 31L), the reflected light of the light 31L reflected by the reflector 22R provided on the sample stage 22 passes through the optical filter 35A and is detected by the detecting element 36A. As a result, the signal output from the detecting element 36A to the computer system 37A has components resulting from the scattered light 45, which are noise components, removed in advance.

[0065] The explanation given using FIG. 4 can be similarly applied to the optical measurement device 300A shown in FIG. 5, so a duplicated explanation will be omitted.

[0066] Except for the above-mentioned differences, the optical measurement device 300A shown in Fig. 5 is similar to the optical measurement device 300 shown in Fig. 3. Therefore, a duplicated description will be omitted.

[0067] <Modification 2> Next, a modification of the charged particle beam device 100A, light irradiation device 200A, and optical measurement device 300A shown in Fig. 5 will be described. Fig. 6 is an explanatory diagram showing an example of the configuration of an optical measurement device that is a modification of Fig. 5. In the configuration example shown in Fig. 5, the configuration obtained by removing the computer system 37A corresponds to the light irradiation device 200B of this modification. In addition, in the configuration example shown in Fig. 6, the configuration obtained by adding the electron optical device 10 shown in Fig. 1 corresponds to the charged particle beam device 100B of this modification.

[0068] The measurement device 30B shown in FIG. 6 is a device that optically measures the distance to an irradiated object (the position of the irradiated object). The measurement device 30B differs from the measurement device 30A shown in FIG. 5 in that it measures the position of the sample stage 22 by irradiating light 31L onto the sample stage 22 (more specifically, the side surface of the sample stage 22). The measurement device 30B includes a light source 31B as a light projector, a detection element 36B as a light receiver, and an optical filter 35B disposed midway along the optical path connecting the sample 2 and the detection element 36B. The measurement device 30B also includes a computer system 37B that is electrically connected to the detection element 36B and is capable of measuring (detecting) the distance to the sample stage 22 (the position of the sample stage 22) based on the output signal of the detection element 36B.

[0069] In this modified example, since the distance to the sample stage 22 (the position of the sample stage 22) is measured, the light source 31B and the detection element 36B are each disposed to the side of the sample stage 22. Light 31L emitted from the light source 31B is reflected by the object to be irradiated (the sample stage 22 in the example shown in FIG. 6 ), passes through the optical filter 35B, and enters the detection element 36B.

[0070] Upon receiving the reflected light of light 31L, the detecting element 36B outputs a signal corresponding to the received light to the computer system 37B. The computer system 37B has a memory 37M. The memory 37M stores reference data for converting the signal data received from the detecting element 36B into the position of the sample stage 22. The computer system 37B determines the position of the sample stage 22 by comparing the signal data received from the detecting element 36B with the reference data stored in the memory 37M. In other words, upon receiving the reflected light of light 31L, the detecting element 36B outputs a signal corresponding to the position of the sample stage 22, thereby detecting the distance to the sample stage 22 (the position of the sample stage).

[0071] In the measurement device 30B of this modified example, a case will be considered in which, when the detection element 36B receives the reflected light of the light 31L, a portion of the scattered light 45 of the laser light 44 or the transmitted light 46 of the laser light 44 transmitted through the sample 2 is incident on the detection element 36B. In this case, the components resulting from the scattered light 45 or the transmitted light 46 in the signal transmitted to the computer system 37B are noise. Therefore, if the scattered light 45 or the transmitted light 46 enters the detection element 36B, it will cause a decrease in the measurement accuracy of the measurement device 30B. Furthermore, depending on the level of the components resulting from the scattered light 45 or the transmitted light 46, it may become impossible for the measurement device 30B to perform measurement.

[0072] Therefore, the optical measuring device 300B (light irradiation device 200B or charged particle beam device 100B, hereinafter the same in this modified example) in this modified example has the following configuration, thereby preventing scattered light 45 from entering the detection element 36B.

[0073] That is, the optical measurement device 300B includes a measurement device (optical device) 30B and a wavelength-tunable laser light irradiation device (optical device) 40. The measurement device 30B includes a light source 31 capable of irradiating light 31L having a certain wavelength, a detection element 36B that detects reflected light obtained when the light 31L is irradiated onto the side surface of the sample stage 22, and an optical filter 35B that is arranged midway along the optical path connecting the sample 2 and the detection element 36B.

[0074] The optical path connecting the sample 2 and the detecting element 36B can be expressed in detail as follows. That is, the optical path is an optical path that, among multiple optical paths of scattered light 45 generated when the laser light 44 is irradiated onto the sample 2, travels toward the detecting element 36B in a straight line or by refraction or reflection. Alternatively, the optical path is an optical path along which transmitted light 46, generated when the laser light 44 is irradiated onto the sample 2 and a portion of the light passes through the sample 2, travels toward the detecting element 36B in a straight line or by refraction or reflection. The definition of the "optical path connecting the sample and the detecting element" is the same in this modification, the embodiment described using FIGS. 1 to 4, the embodiment according to Modification 1 described using FIG. 5, and each modification described after this modification.

[0075] Optical filter 35B has the property of reflecting or absorbing (blocking) light having the wavelengths of laser light 44S and laser light 44L. Therefore, optical filter 35B can block and filter scattered light 45 and transmitted light 46, thereby preventing scattered light 45 and transmitted light 46 from entering detection element 36.

[0076] On the other hand, optical filter 35B has the property of passing light of the wavelength of light 31L. Therefore, even if optical filter 35B is disposed in the optical path connecting sample 2 and detection element 36B (more specifically, the optical path of reflected light of light 31L), the reflected light of light 31L reflected on the side surface of sample stage 22 passes through optical filter 35B and is detected by detection element 36B. As a result, components attributable to scattered light 45, which is a noise component, are removed in advance from the signal output from detection element 36B to computer system 37B.

[0077] The explanation given with reference to FIG. 4 can be similarly applied to the optical measurement device 300B shown in FIG. 6, and therefore a duplicated explanation will be omitted.

[0078] Except for the above-mentioned differences, the optical measurement device 300B shown in Fig. 6 is similar to the optical measurement device 300 shown in Fig. 3. Therefore, a duplicated description will be omitted.

[0079] <Modification 3> Next, as other modifications of the optical measurement device 300 shown in FIG. 3 , an embodiment in which multiple optical filters are used in a switchable manner as a noise filter for blocking noise component light, and an embodiment in which the wavelength-tunable laser light irradiator 40 has an even wider wavelength tuning range, will be described. FIG. 7 is an explanatory diagram showing an example of the configuration of an optical measurement device that is another modification of FIG. 3 . FIG. 8 is an explanatory diagram showing an example of the spectral characteristics of one of the multiple optical filters shown in FIG. 7 . FIG. 9 is an explanatory diagram showing an example of the spectral characteristics of the other of the multiple optical filters shown in FIG. 7 . FIG. 10 is an explanatory diagram showing the range of the wavelength band of light that can be output by the wavelength-tunable light source shown in FIG. 7 . The configuration example shown in FIG. 7 , minus the computer system 37, corresponds to a light irradiation device 200D of this modification. Furthermore, the configuration example shown in FIG. 7 , plus the electron optical device 10 shown in FIG. 1, corresponds to a charged particle beam device 100D of this modification.

[0080] An optical measurement device 300D (light irradiation device 200D or charged particle beam device 100D, hereinafter the same in this modification) according to this modification differs from the optical measurement device 300 shown in FIG. 3 in the following points.

[0081] The optical measurement device 300D includes a measurement device (optical measurement device) 30D and a wavelength-tunable laser light irradiation device (optical device) 40D.

[0082] The measurement device 30D is an optical sample measurement device capable of optically measuring the physical quantities of the sample 2. In the present embodiment, the measurement device 30D has the function of optically measuring the height of the sample 2, similar to the measurement device 30 shown in Fig. 3. The measurement device 30D includes a light source 31, a light source-side lens 33, a detection-side lens 34, an optical filter 35D1, an optical filter 35D2, an optical filter switching mechanism 35D, a detection element 36, a computer system 37, and a computer system 38.

[0083] Light 31L emitted from the light source 31 of the measurement device 30D passes through a light source-side lens 33 and forms an image on the surface of the sample 2. As shown in FIG. 10 , the light 31L is polychromatic light (broadband light) such as white light, and includes a wavelength band (intermediate wavelength band) λ1, a wavelength band (long wavelength band) λ2, and a wavelength band (short wavelength band) λ3. The light 31L is reflected from the surface of the sample 2, passes through a detection-side lens 34 and an optical filter 35D1 (or optical filter 35D2), and forms an image again on the surface of the detection element 36. An output signal from the detection element 36 is transmitted to a computer system 37.

[0084] The measurement device 30D differs from the measurement device 30 shown in Fig. 3 in that it switches between multiple optical filters. In the example shown in Fig. 7, the measurement device 30D has an optical filter 35D1 and an optical filter 35D2. The optical filters 35D1 and 35D2 have different spectral characteristics.

[0085] For example, the optical filter 35D1 has spectral characteristics that block light in the wavelength band λ4, which is a short wavelength band, and pass light in the wavelength band λ5, which is a long wavelength band, as shown in Fig. 8. The optical filter 35D1 (see Fig. 7) having the spectral characteristics shown in Fig. 8 is called a high-pass filter.

[0086] On the other hand, the optical filter 35D2 shown in Fig. 7 has spectral characteristics that pass light in the wavelength band λ4, which is a short wavelength band, and block light in the wavelength band λ5, which is a long wavelength band, as shown in Fig. 9. The optical filter 35D2 (see Fig. 7) having the spectral characteristics shown in Fig. 9 is called a low-pass filter.

[0087] The wavelength-tunable laser beam irradiator 40D shown in FIG. 7 includes a light source 42D capable of irradiating laser beam 44 and a light control unit (computer system) 41D capable of controlling the conditions (e.g., wavelength) of the laser beam 44 emitted from the light source 42D. The light source 42D is a light irradiator capable of selecting the wavelength of the laser beam 44 in a wider wavelength band than the light source 42 shown in FIGS. 1 to 3 . For example, as shown in FIG. 10 , in this modification, the wavelength of the laser beam 44 that can be emitted from the light source 42D (see FIG. 10 ) includes a wavelength band (long wavelength band) λ2, a wavelength band (short wavelength band) λ3, and a wavelength band (intermediate wavelength band) λ1. A data signal of the light source element selected by the light control unit 41D is transmitted to the computer system 38.

[0088] Each of the multiple optical filters (optical filter 35D1 and optical filter 35D2) shown in Fig. 7 is capable of transmitting a portion of the wavelength of light 31L. For example, optical filter 35D1 (see Fig. 7) having the spectral characteristics shown in Fig. 8 can transmit a portion of the λ5 wavelength band of broadband light 31L. Optical filter 35D2 (see Fig. 7) having the spectral characteristics shown in Fig. 9 can transmit a portion of the λ4 wavelength band of broadband light 31L. Optical filters 35D1 and 35D2 are also capable of blocking light (laser light 44) emitted from light source 42D.

[0089] In the wavelength-tunable laser beam irradiator 40D, a light control unit (computer system) 41D selects light having a wavelength included in the wavelength band λ4 shown in Fig. 8, and when laser beam 44 is emitted from the light source 42D, an optical filter 35D1 (see Fig. 7) having the spectral characteristics shown in Fig. 8 is disposed midway along the optical path connecting the sample 2 and the detecting element 36 shown in Fig. 7. At this time, scattered light of the laser beam 44 is blocked, and light having a wavelength in the wavelength band λ5 of the light 31L is incident on the detecting element 36.

[0090] On the other hand, in the wavelength-tunable laser beam irradiator 40D, when a light control unit (computer system) 41D selects light having a wavelength included in the wavelength band λ5 shown in Fig. 9 and laser beam 44 is emitted from the light source 42D, an optical filter 35D2 (see Fig. 7) having the spectral characteristics shown in Fig. 9 is disposed midway along the optical path connecting the sample 2 and the detecting element 36 shown in Fig. 7. At this time, scattered light of the laser beam 44 is blocked, and light having a wavelength in the wavelength band λ4 of the light 31L is incident on the detecting element 36.

[0091] The switching between the optical filter 35D1 and the optical filter 35D2 shown in FIG. 7 is performed by the computer system 38 and the optical filter switching mechanism 35D.

[0092] The computer system 38 includes a control circuit capable of selecting an optical filter disposed midway along the optical path connecting the sample 2 and the detection element 36 in accordance with the wavelength of the laser light 44 irradiated by the wavelength-tunable laser light irradiator 40D toward the sample 2. In other words, the computer system 38 controls the optical filter switching mechanism 35D in accordance with switching of the wavelength of the laser light 44 so as to selectively pass light of a wavelength different from that of the light irradiated from the wavelength-tunable laser light irradiator 40D (laser light 44). The computer system 38 selects an appropriate optical filter based on the data signal of the light source element selected by the light control unit 41D.

[0093] The optical filter switching mechanism 35D is a driving device for an optical filter that can position an optical filter selected from multiple optical filters (optical filter 35D1 and optical filter 35D2) in the middle of the optical path connecting the sample 2 and the detection element 36 based on a control signal output by the computer system 38.

[0094] As in the example shown in Fig. 7, when two optical filters are used in a switchable manner, the positions of the optical filters can be changed by linearly sliding them, as shown schematically by the arrows in Fig. 7. Although not shown, in addition to the sliding method exemplified in Fig. 7, a revolver method can also be applied, in which a plurality of optical filters arranged in a ring shape are moved by rotating them around the center of the ring as the rotation axis. The revolver method is particularly effective, for example, when three or more optical filters are used in a switchable manner.

[0095] According to this modified example, the optical filter (optical filter 35D1 or optical filter 35D2) selected by the computer system 38 and placed in the optical path connecting the sample 2 and the detection element 36 by the optical filter switching mechanism 35D is capable of blocking light having the same wavelength as the laser light 44.

[0096] Therefore, according to this modification, of the multiple scattered light beams 45, the scattered light beams 45 that travel toward the detection element 36 are blocked by the optical filter 35D1 or the optical filter 35D2, and are therefore less likely to enter the detection element 36. As a result, the measurement accuracy of the measurement device 30D can be improved.

[0097] As in the case of the charged particle beam device 100 described using Figures 1 to 4, in the case of the charged particle beam device 100D shown in Figure 7, for example, the laser light 44 is irradiated onto the sample 2 simultaneously with the light 31L and the electron beam irradiated by the electron optical device 10 (see Figure 1).

[0098] In the case of the measurement device 30D shown in FIG. 7 , for example, the multiple optical filters include an optical filter 35D2 that blocks light in the intermediate wavelength band λ1 (see FIG. 10 ) and wavelengths longer than the intermediate wavelength band λ1, and an optical filter 35D1 that blocks light in the intermediate wavelength band λ1 and wavelengths shorter than the intermediate wavelength band λ1. Among the multiple optical filters, an optical filter that blocks light having the same wavelength as the laser light 44 is selected and used by switching between them. As described above, the light 31L emitted from the light source 31 of the measurement device 30D is polychromatic light, and includes the wavelength band (long wavelength band) λ2 (see FIG. 10 ) and the wavelength band (short wavelength band) λ3 (see FIG. 10 ) in addition to the wavelength band (intermediate wavelength band) λ1 of the light 31L. In this case, even if the laser light 44 in the intermediate wavelength band λ1, which was not irradiated by the wavelength-tunable laser light irradiating device 40 of FIG. 1 , is irradiated onto the sample 2, the scattered light 45 traveling toward the detection element 36 is blocked by the optical filter 35D1 or the optical filter 35D2. On the other hand, a portion of light 31L emitted from light source 31 of measurement device 30D passes through optical filter 35D1 or optical filter 35D2 and enters detection element 36. Therefore, the wavelength of laser light 44 in Fig. 7 can be emitted in wavelength band (long wavelength band) λ2, wavelength band (short wavelength band) λ3, and also in wavelength band (intermediate wavelength band) λ1.

[0099] In this modified example, an embodiment using a high-pass filter having the spectral characteristics shown in FIG. 8 and a low-pass filter having the spectral characteristics shown in FIG. 9 has been described as an example of an embodiment in which optical filters are used in a switchable manner. However, various modifications of the spectral characteristics of the optical filters used in a switchable manner in addition to the examples shown in FIGS. 8 and 9 can be applied. For example, as shown in FIG. 4 , multiple types of optical filters having spectral characteristics that transmit light in wavelength band λ1 and block light in wavelength bands λ2 and λ3, and that have different ranges of wavelength band λ1 (i.e., ranges of wavelength bands that are transmitted), may be used in a switchable manner. In this case, when the light emitted from the light source 31 is polychromatic light such as white light including a wavelength band (intermediate wavelength band) λ1, a wavelength band (long wavelength band) λ2, and a wavelength band (short wavelength band) λ3, or when the wavelength of the laser light 44 is changed, an appropriate optical filter can be selected and used depending on the wavelength of each light.

[0100] <Modification 4> Next, an embodiment in which a plurality of light source elements are used by switching them will be described as another modification of the light source 42D shown in Fig. 7. Fig. 11 is an explanatory diagram showing a modification of the wavelength-tunable laser beam irradiator shown in Fig. 7. By replacing the wavelength-tunable laser beam irradiator 40D shown in Fig. 7 with the wavelength-tunable laser beam irradiator 40E shown in Fig. 11, a light irradiation device, optical measurement device, or charged particle beam device according to this modification can be obtained.

[0101] In this modification, the light 31L is polychromatic light (broadband light) such as white light, and includes a wavelength band (intermediate wavelength band) λ1, a wavelength band (long wavelength band) λ2, and a wavelength band (short wavelength band) λ3, as in the above-described modification 3.

[0102] 11 includes a light source 42E capable of emitting laser light 44 and a light control unit (computer system) 41E capable of controlling the conditions of the laser light 44 emitted from the light source 42E (e.g., the on / off operation of a light source element). The light source 42E includes a plurality of light source elements (light source element 42E1 and light source element 42E2) capable of emitting light of different wavelengths. The light control unit 41E is capable of selecting one of the plurality of light source elements and controlling the selected light source element to emit laser light 44.

[0103] In this modification, the light source element 42E1 can emit laser light 44S1 with a short wavelength, for example, included in the wavelength band λ4 (see FIG. 8), which is a short wavelength band. On the other hand, the light source element 42E2 can emit laser light 44L1 with a long wavelength, for example, included in the wavelength band λ5 (see FIG. 8), which is a long wavelength band. The laser light 44S1 and the laser 44L1 may each be wavelength-tunable light whose wavelength can be changed within the range of the above-mentioned wavelength band. Alternatively, the laser light 44S1 and the laser 44L1 may each be monochromatic light included in the range of the above-mentioned wavelength band.

[0104] 11 controls the selected light source element to emit laser light 44. The data signal of the light source element selected by the light control unit 41E is transmitted to the computer system 38.

[0105] On the other hand, the computer system 38 shown in FIG. 7 selects an optical filter from among a plurality of optical filters (optical filter 35D1 or optical filter 35D2) that is capable of blocking light of the wavelength of the laser light 44 based on the data signal of the light source element selected by the light control unit 41E, and controls the optical filter switching mechanism 35D so that the selected optical filter is positioned midway along the optical path connecting the sample 2 and the detection element 36.

[0106] The light control unit 41E and the computer system 38 may be independent computer systems or may be an integrated computer system.

[0107] According to this modification, the light control unit 41E controls the on / off of a plurality of light source elements included in the light source 42E, thereby selecting the wavelength of the laser light 44. Therefore, switching the wavelength of the laser light 44 is easy.

[0108] <Modification 5> Next, as a modification of the light source 31 shown in Fig. 7 , an embodiment in which the light source 31 is a light source that switches between a plurality of light source elements will be described. Fig. 12 is an explanatory diagram showing an example of the configuration of an optical measurement device that is a modification of Fig. 7 . Fig. 13 is an explanatory diagram showing an example of the range of the wavelength band of light that can be output by the wavelength-tunable light source shown in Fig. 12 and the wavelength range of light emitted from the light source for the measurement device shown in Fig. 12 . By replacing the wavelength-tunable laser light irradiation device 40D shown in Fig. 7 with the measurement device (optical device) 30F shown in Fig. 12 , a light irradiation device 200F, an optical measurement device 300F, or a charged particle beam device 100F according to this modification can be obtained.

[0109] A measurement device 30F included in an optical measurement device 300F, which is a modified example shown in Fig. 12, differs from the measurement device 30D shown in Fig. 7 in that a light source 31F has a plurality of light source elements (light source element 31F1 and light source element 31F2 in the example of Fig. 12) that can irradiate light of different wavelengths. Furthermore, a measurement device 32F can select a light source element that irradiates light 31L from among the plurality of light source elements included in the light source 31F.

[0110] As illustrated in FIG. 13 , light 31L emitted from light source 31F (see FIG. 12 ) has wavelengths in a narrow band. For example, light 31L1 emitted from light source element 31F1 (see FIG. 12 ) has wavelengths in a portion of the wavelength band (short wavelength band) λ3. Light 31L2 emitted from light source element 31F2 (see FIG. 12 ) has wavelengths in a portion of the wavelength band (long wavelength band) λ2. In the example illustrated in FIG. 13 , the wavelengths of light 31L1 and light 31L2 do not include the wavelength band (intermediate wavelength band) λ1, but in a modified example not shown, they may include the wavelength band λ1. Although not illustrated, light 31L1 and light 31L2 shown in FIG. 13 may each have a single wavelength that is different from each other.

[0111] In this modified example, since the light source 31F can irradiate light of different wavelengths as the light 31L, the computer system 38F shown in Fig. 12 can select an optical filter from a plurality of optical filters (optical filters 35F1 and 35F2) to be placed in the optical path connecting the sample 2 and the detection element 36, depending on the wavelength of the light 31L (light 31L1 or light 31L2 shown in Fig. 13) irradiated from the light source 31F and the wavelength of the laser light 44 irradiated by the wavelength-tunable laser light irradiator 40D toward the sample 2. The switching between the optical filter 35F1 and the optical filter 35F2 shown in Fig. 12 is performed by the computer system 38 and the optical filter switching mechanism 35F.

[0112] 12, the measurement device 30F has a light control unit (computer system) 32. The light control unit 32 is a computer system that can select one of a plurality of light source elements (light source elements 31F1 and 31F2 in the example of FIG. 12) as the light source of the light emitted from the light source 31F.

[0113] A data signal of the light source element selected by the light control unit 32 is transmitted from the light control unit 32 to the computer system 38 directly or via the light control unit 41D. Also, similar to the embodiment described in Modification 3, a data signal related to the wavelength of the laser light 44 selected by the light control unit 41D is transmitted to the computer system 38. The computer system 38 selects an appropriate optical filter based on the data signal of the light source element selected by the light control unit 32 and the data signal related to the wavelength of the laser light 44 selected by the light control unit 41D.

[0114] For example, when light source element 31F1 is selected by light control unit 32 and the light source element selected by light control unit 41D irradiates laser light 44 having a wavelength included in either wavelength band λ1 (see FIG. 13) or wavelength band λ2 (see FIG. 13), optical filter 35F1 (see FIG. 12) that can selectively transmit the wavelength of light 31L1 shown in FIG. 13 and can block laser light 44 is selected by computer system 38 (see FIG. 12).

[0115] Furthermore, for example, when light source element 31F2 is selected by light control unit 32 shown in FIG. 12 and the light source element selected by light control unit 41D irradiates laser light 44 having a wavelength included in either wavelength band λ1 (see FIG. 13) or wavelength band λ3 (see FIG. 13), optical filter 35F2 (see FIG. 12) that can selectively transmit the wavelength of light 31L2 shown in FIG. 13 and can block laser light 44 is selected by computer system 38 (see FIG. 12).

[0116] Furthermore, in this modified example, when the light control unit 41D selects the wavelength of the laser light 44, it is preferable that the light control unit 41D selects the wavelength based on the data signal of the light source element selected by the light control unit 32. As shown by the dotted line in Fig. 12, the data signal of the light source element selected by the light control unit 32 is transmitted to the light control unit 41D. The light control unit 41D selects the wavelength of the laser light 44 so that the wavelength of the laser light 44 is different from the wavelength of the light 31L.

[0117] In the above-described embodiments and modifications, the focus has been placed on the wavelength of light, but the reciprocal of the wavelength is frequency. Therefore, in the above description, the term "wavelength" can be replaced with "frequency." However, since frequency is the reciprocal of wavelength as described above, the term "long wavelength" must be replaced with "low frequency." Furthermore, "short wavelength" must be replaced with "high frequency." Furthermore, the terms "long wavelength" and "short wavelength" can be replaced with "low frequency" and "high frequency," respectively.

[0118] The present invention has been specifically described above based on the above embodiment, but the present invention is not limited to the above embodiment and can be modified in various ways without departing from the spirit of the present invention.

[0119] For example, although each of Modifications 2 and 3 has been described as a modification of the embodiment described using Figures 1 to 4, they can also be applied as a modification of the light irradiation device 200D, the optical measurement device 300D, or the charged particle beam device 100D described using Figure 7. Similarly, the wavelength-tunable laser beam irradiation device 40 shown in Figure 1 or the wavelength-tunable laser beam irradiation device 40D shown in Figure 12 can be replaced with the wavelength-tunable laser beam irradiation device 40E described using Figure 11.

[0120] In the above description, an optical device used to change the signal amount (emission amount) of secondary charged particles is taken as an example of a wavelength-tunable laser beam irradiator. However, examples of wavelength-tunable laser beam irradiators are not limited to the above, and various modifications can be applied.

[0121] 2 Sample 10 Electron optical device (electron optical system) 11 Electron gun 12 Deflector 13 Secondary electron detector 14 Electron lens 20 Sample support device (sample support system) 21 Sample holder 22 Sample stage 23 Stage drive mechanism 30, 30A, 30B, 30D, 30F Measurement device (optical measurement device, optical device) 31, 31A, 31B, 42, 42D, 42E Light source 31L Light 32, 37, 37A, 37B, 37, 38 Computer system 33 Light source side lens 34 Detection side lens 35, 35A, 35B, 35D1, 35D2, 35F1, 35F2 Optical filter 35D Optical filter switching mechanism 36, 36A, 36B Detection element (light receiving element) 37M Memory 40, 40D, 40E Wavelength-tunable laser light irradiation device (optical device) 41, 41D, 41E Light control unit (computer system) 42E1, 42E2 Light source element 43 Harmonic generator 44, 44L, 44L1, 44S, 44S1 Laser light 45 Scattered light 46 Transmitted light 100, 100A, 100B, 100D, 100F Charged particle beam device 200, 200A, 200B, 200D, 200F Light irradiation device 300, 300A, 300B, 300D, 300F Optical measurement device λ1, λ2, λ3, λ4, λ5 Wavelength band

Claims

1. A light irradiation device comprising: a first optical device including a first light source capable of irradiating a first light having a first wavelength, a detection element that detects reflected light obtained when the first light is irradiated onto a sample, and an optical filter that is arranged midway along an optical path connecting the sample and the detection element; and a second optical device including a second light source capable of irradiating a second light having a second wavelength different from the first wavelength, and a harmonic generator that is capable of converting a portion of the second light into third light having a third wavelength shorter than the second wavelength, and that is capable of irradiating the sample with one or both of the second light and the third light, wherein the third wavelength is different from the first wavelength, and the optical filter is capable of blocking light of the second wavelength and the third wavelength and allowing light of the first wavelength to pass.

2. A light irradiation device according to claim 1, wherein the second wavelength is longer than the first wavelength, and the third wavelength is shorter than the first wavelength.

3. An optical measurement apparatus according to claim 1, comprising: the light irradiation device; and one or more computer systems electrically connected to the detection element of the first optical device and capable of measuring physical quantities of the sample based on output signals from the detection element.

4. A charged particle beam device according to claim 3, comprising: the optical measurement device; and an electron optical device capable of detecting secondary charged particles obtained by irradiating the sample with an electron beam.

5. A charged particle beam device according to claim 4, wherein one or both of the second light and the third light are irradiated onto the sample simultaneously with the first light and the electron beam.

6. A charged particle beam apparatus according to claim 5, further comprising a sample stage for supporting the sample, wherein the first optical device measures the height of the sample, the presence or absence of the sample, or the position of the sample stage.

7. A first optical device including a first light source capable of irradiating first light having a first wavelength band, a detection element that detects reflected light obtained when the first light is irradiated onto a sample, and a plurality of optical filters that can be arranged in an optical path connecting the sample and the detection element; a second optical device including a second light source that can irradiate second light; and one or more computer systems that can select an optical filter from the plurality of optical filters to be arranged in the optical path connecting the sample and the detection element in accordance with the wavelength of the second light that the second optical device irradiates toward the sample, wherein the second light source is a wavelength-tunable light source that can change the wavelength of the second light in a wavelength band that includes the first wavelength band; the first optical device includes an optical filter switching mechanism that can arrange an optical filter selected from the plurality of optical filters in the optical path connecting the sample and the detection element based on a control signal output by the one or more computer systems; and each of the plurality of optical filters is capable of passing a part of the first wavelength band. a light irradiation device, wherein an optical filter selected by the one or more computer systems and placed in the optical path connecting the sample and the detection element by the optical filter switching mechanism is capable of blocking the second light.

8. A light irradiation device according to claim 7, wherein the plurality of optical filters include a first optical filter that blocks light of a long wavelength, and a second optical filter that blocks light of a short wavelength.

9. An optical measurement apparatus according to claim 7, comprising the light irradiation device, wherein the one or more computer systems are electrically connected to the detection element of the first optical device and are capable of measuring a physical quantity of the sample based on an output signal from the detection element.

10. An optical measurement device according to claim 9, wherein the second light source includes a plurality of light source elements capable of emitting light of mutually different wavelengths, and the one or more computer systems are capable of: selecting one of the plurality of light source elements and controlling the selected light source element to emit the second light; and selecting an optical filter from the plurality of optical filters that is capable of blocking the second light, and controlling the optical filter switching mechanism so that the selected optical filter is positioned midway in the optical path connecting the sample and the detection element.

11. A charged particle beam device according to claim 9, comprising: the optical measurement device; and an electron optical device capable of detecting secondary charged particles obtained by irradiating the sample with an electron beam.

12. A charged particle beam device according to claim 11, wherein the second light is irradiated onto the sample simultaneously with the first light and the electron beam.

13. A charged particle beam apparatus according to claim 12, further comprising a sample stage for supporting the sample, wherein the first optical device measures the height of the sample, the presence or absence of the sample, or the position of the sample stage.

14. A first optical device including a first light source having a plurality of light source elements capable of irradiating light of different wavelengths from each other, the first light source being capable of irradiating a first light from any of the plurality of light source elements, a detection element detecting reflected light obtained when the first light is irradiated onto a sample, and a plurality of optical filters that can be arranged along an optical path connecting the sample and the detection element; a second optical device including a second light source capable of irradiating a second light; and one or more computer systems that can select an optical filter from the plurality of optical filters to be arranged along the optical path connecting the sample and the detection element in accordance with the wavelength of the first light irradiated from the first light source and the wavelength of the second light irradiated towards the sample by the second optical device, wherein the second light source is a wavelength-variable light source that can change the wavelength of the second light, and the first optical device includes an optical filter switching mechanism that can arrange an optical filter selected from the plurality of optical filters along the optical path connecting the sample and the detection element based on a control signal output by the one or more computer systems, a light irradiation device, wherein an optical filter selected by the one or more computer systems and placed in the optical path connecting the sample and the detection element by the optical filter switching mechanism is capable of blocking the second light.

15. A light irradiation device according to claim 14, wherein the one or more computer systems are capable of selecting the second light so that the wavelength of the second light is different from the wavelength of the first light.

16. An optical measurement apparatus according to claim 15, comprising the light irradiation device, wherein the one or more computer systems are electrically connected to the detection element of the first optical device and are capable of measuring a physical quantity of the sample based on an output signal from the detection element.

17. A charged particle beam device according to claim 16, comprising: the optical measurement device; and an electron optical device capable of detecting secondary charged particles obtained by irradiating the sample with an electron beam.

18. A charged particle beam device according to claim 17, wherein the second light is irradiated onto the sample simultaneously with the first light and the electron beam.

Images