Cathodoluminescence spectrometer

Abstract

A cathodoluminescence spectrometer is provided. The cathodoluminescence spectrometer (100) includes an electron gun (10), a mirror (20), a standard element (30), a detector (40), and a control device (50). The standard element (30) includes a first half mirror and a second half mirror. The second half mirror is disposed at a position facing the first half mirror. The first half mirror reflects a portion of cathodoluminescence (CL2) that has been converged by the mirror (20) and transmits a portion thereof. The second half mirror reflects a portion of cathodoluminescence that has been transmitted through the first half mirror and transmits a portion thereof. The first half mirror and the second half mirror cause cathodoluminescence between the first half mirror and the second half mirror to interfere, thereby causing cathodoluminescence (CL3) of a specific wavelength to be transmitted through the second half mirror. The detector (40) detects the intensity of cathodoluminescence (CL3) that has been transmitted through the second half mirror.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a cathodoluminescence spectroscopic device. BACKGROUND

[0002] Conventionally, a technique of detecting cathodoluminescence emitted from a sample to obtain information on distribution of crystal defects or impurities of the sample or the like is known.

[0003] For example, a cathodoluminescence spectroscopic device disclosed in Japanese Patent Application Publication No. 2000-206046 is configured to generate cathodoluminescence by irradiating an electron beam to a sample, and to spectrally analyze the cathodoluminescence using a spectroscopic crystal. SUMMARY

[0004] In the cathodoluminescence spectroscopic device of Japanese Patent Application Publication No. 2000-206046, a spectroscopic crystal is used as a spectrometer, and thus the spectroscopic crystal itself needs to be arranged inside the cathodoluminescence spectroscopic device. Therefore, the cathodoluminescence spectroscopic device needs to be provided with a space for arranging the spectroscopic crystal, and the spectrometer can be large-sized. As a result, there is a concern that the cathodoluminescence spectroscopic device itself can also be large-sized.

[0005] The present application has been achieved in order to solve such a problem, and aims at achieving miniaturization of a spectrometer for spectrally analyzing cathodoluminescence in a cathodoluminescence spectroscopic device.

[0006] The cathodoluminescence spectroscopic device of the present disclosure includes an electron gun, a condensing mechanism, a spectroscopic element, a detector, and a control device. The electron gun irradiates an electron beam to a sample. The condensing mechanism condenses cathodoluminescence emitted from the sample by irradiating the electron beam to the sample. The spectroscopic element is configured to be able to spectrally analyze the cathodoluminescence condensed by the condensing mechanism. The detector detects intensity of the cathodoluminescence spectrally analyzed by the spectroscopic element. The control device receives a detection result from the detector to control the cathodoluminescence spectroscopic device. The spectroscopic element includes a first half mirror and a second half mirror. The second half mirror is arranged at a position facing the first half mirror. The first half mirror reflects a part of the cathodoluminescence condensed by the condensing mechanism, and transmits a part of the cathodoluminescence condensed by the condensing mechanism. The second half mirror reflects a part of the cathodoluminescence transmitted through the first half mirror, and transmits a part of the cathodoluminescence transmitted through the first half mirror. The first half mirror and the second half mirror cause the cathodoluminescence between the first half mirror and the second half mirror to interfere, and thus cathodoluminescence of a specific wavelength is transmitted through the second half mirror. The detector detects intensity of the cathodoluminescence transmitted through the second half mirror.

[0007] The above objects, features, aspects and advantages of the present application will become more apparent from the following detailed description of the present application taken in conjunction with the accompanying drawings, in which: BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 is a diagram showing an outline of the cathodoluminescence spectrometer of Embodiment 1.

[0009] Figure 2 is an outline diagram of the etalon element and the detector.

[0010] Figure 3 is a diagram showing multiple interference of the etalon element.

[0011] Figure 4 is a diagram showing a display example of the luminescence intensity of the cathodoluminescence emitted from the sample of Embodiment 1.

[0012] Figure 5 is a diagram showing an outline of the cathodoluminescence spectrometer of Embodiment 2.

[0013] Figure 6 is a perspective view of a sample irradiated with an electron beam.

[0014] Figure 7 is a perspective view of the etalon element and the detector which is a CCD.

[0015] Figure 8 is a diagram showing a display example of the luminescence intensity of the cathodoluminescence emitted from the sample of Embodiment 2.

[0016] Figure 9 is a diagram showing an example of the spectrum of the light-receiving element corresponding to the region of Figure 8 .

[0017] Figure 10 is a diagram showing an example of the spectrum of the light-receiving element corresponding to the region of Figure 8 .

[0018] Figure 11 is a diagram showing an example of the spectrum of the light-receiving element corresponding to the region of Figure 8 .

[0019] Figure 12 is a diagram showing an outline of the cathodoluminescence spectrometer of Embodiment 3.

[0020] Figure 13 is a diagram for explaining the incident angle of the electron beam of Embodiment 3.

[0021] Figure 14 is a diagram showing the structure of the cathodoluminescence spectrometer of Embodiment 4.

[0022] Figure 15 is a diagram showing the spectrum in the case where the etalon element is used.

[0023] Figure 16This is a diagram showing a spectrum when a spectroscopic crystal is used.

[0024] Figure 17 This is a flowchart showing the analysis process of switching from the etalon element to the spectroscopic crystal.

[0025] Figure 18 This is a diagram illustrating the superposition of images. DETAILED DESCRIPTION

[0026] [Implementation Method 1]

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and their description will not be repeated.

[0028] <Overall Structure of Cathodoluminescence Spectrometer>

[0029] Figure 1 This figure shows an overview of cathodoluminescence spectrometer 100 according to Embodiment 1. Cathodoluminescence spectrometer 100 according to Embodiment 1 is, for example, a scanning electron microscope (SEM) that scans and irradiates a sample with an electron beam. Cathodoluminescence spectrometer 100 is not limited to an electron microscope; any device capable of irradiating a sample with an electron beam may be used.

[0030] Cathodoluminescence spectrometer 100 includes electron gun 10 , sample stage 15 , reflecting mirror 20 , condensing lens 25 , etalon element 30 , detector 40 , and control device 50 . Electron gun 10 includes electron source 11 , condensing lens 12 , scanning coil 13 , and objective lens 14 .

[0031] In the following description, the normal direction of the sample stage 15 is defined as the Z-axis direction, and the planes perpendicular to the Z-axis direction are defined as the X-axis and the Y-axis. In the figures, the positive direction of the Z-axis is sometimes referred to as the upper surface side, and the negative direction is sometimes referred to as the lower surface side.

[0032] The electron gun 10 irradiates the sample Sp1 placed on the sample stage 15 with an electron beam EB1. The surface of the sample Sp1 placed on the sample stage 15 on the positive side of the Z axis is parallel to the surface of the sample stage 15. A reflector 20 is disposed between the electron gun 10 and the sample Sp1. The electron beam EB1 passes through an opening 20a formed in the reflector 20 and then enters the sample Sp1.

[0033] The electron source 11 is an excitation source for the electron beam EB1 and emits the electron beam EB1 when a voltage is applied. The condenser lens 12 converges the electron beam EB1. The scanning coil 13 scans the electron beam EB1 over the sample Sp1. The objective lens 14 reduces the electron beam EB1 to a small diameter.

[0034] The electron gun 10 is housed in a housing connected to a vacuum exhaust mechanism so that the electron source 11 can generate an electron beam EB1. That is, the housing is kept at a vacuum level sufficient to enable the electron source 11 to generate electrons.

[0035] When electron beam EB1 is irradiated on sample Sp1, electrons in the valence band of sample Sp1 are excited to the conduction band. The resulting holes recombine with the electrons, generating light. This light emission is called cathodoluminescence. Cathodoluminescence radiates in all directions from sample Sp1. Furthermore, cathodoluminescence includes multiple wavelengths. Figure 1 The cathode luminescence CL1 in FIG. 1 is the cathode luminescence emitted toward the reflector 20 among the cathode luminescence emitted in all directions. In other words, the cathode luminescence CL1 is the cathode luminescence from the sample Sp1 to the reflector 20 .

[0036] The reflector 20 reflects the cathode luminescence CL1 emitted from the sample Sp1. The reflector 20 reflects the cathode luminescence CL1 as cathode luminescence CL2. The cathode luminescence CL2 is focused onto the etalon element 30 by the condenser lens 25. Specifically, the cathode luminescence CL2 is the cathode luminescence that remains after being reflected by the reflector 20 and until it is focused onto the etalon element 30. Furthermore, the reflector 20 and the condenser lens 25 correspond to the "condensing mechanism" of the present disclosure. The reflector 20 and the condenser lens 25, which serve as the condensing mechanism, may also be provided as an integrated reflector lens.

[0037] The etalon element 30 is configured to split the cathodoluminescence CL2, which has been focused by the reflector 20 and the focusing lens 25. Specifically, the etalon element 30 is a spectrometer that transmits only specific wavelengths of the cathode luminescence CL2, which includes multiple wavelengths, as cathode luminescence CL3. Hereinafter, the wavelengths of the cathode luminescence CL3 will sometimes be referred to as "split wavelengths." The etalon element 30 is referred to as a Fabry-Perot interferometer. It corresponds to the "spectral splitting element" in this disclosure.

[0038] The dimension of the etalon element 30 in the longitudinal direction is about 5 mm to 15 mm, and the dimension in the width direction is about 1 mm to 5 mm. On the other hand, the size of an ordinary spectroscopic crystal used for spectroscopic cathode luminescence is larger than the size of the etalon element. In addition, a cathode luminescence spectroscopic device equipped with a spectroscopic crystal needs to have an optical system for spectroscopic use of the spectroscopic crystal. The dimension of the spectrometer that accommodates the optical system and the spectroscopic crystal is about 1500 mm to 2500 mm in the longitudinal direction, and about 1500 mm to 2500 mm in the width direction. That is, the space required when configuring the etalon element 30 is smaller than the space required when configuring the spectroscopic crystal.

[0039] The detector 40 detects the intensity of the cathodoluminescence CL3 after the light is split by the etalon element 30. The detector 40 of Embodiment 1 is a photomultiplier (PMT). That is, the detector 40 is a so-called photomultiplier tube. The detector 40 amplifies photoelectrons using a plurality of dynodes provided inside, and detects the intensity of a small amount of light.

[0040] The control device 50 has a CPU 51 (Central Processing Unit) and a memory 52 as main constituent elements. The control device 50 can also be a structure constituted by a dedicated hardware circuit (for example, an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array), or the like). The memory is realized by, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), or an HDD (Hard Disk Drive).

[0041] The control device 50 is electrically connected to the display 60 and the input device 70. The control device 50 causes, for example, information related to the cathodoluminescence splitting to be displayed on the display 60. The information related to the cathodoluminescence splitting includes, for example, the detection result of the detector 40, error information generated in the analysis device, and the like. The control device 50 receives a command input by the user using the input device 70. The input device 70 is, for example, a keyboard. The display 60 and the input device 70 can also be integrally formed as a touch panel.

[0042] At least a part of the structure included in the control device 50, the display 60, or the input device 70 can also be constituted separately from the cathodoluminescence splitting device 100, and configured to communicate bidirectionally with the cathodoluminescence splitting device 100.

[0043] The control device 50 controls the cathodoluminescence splitting device 100 as a whole. The control device 50 receives a detection value from the detector 40. The control device 50 calculates the luminescence intensity of the cathodoluminescence at an arbitrary position in the sample Sp1 based on the voltage value applied to the scanning coil 13 and the detection value received from the detector 40. Thereby, the control device 50 can form an image representing the distribution of the luminescence intensity of the cathodoluminescence in the sample Sp1. The control device 50 causes the formed image to be displayed on the display 60. The etalon element 30 is configured to be able to change the wavelength after the light is split to an arbitrary wavelength.

[0044] <Structure of Etalon Element>

[0045] In the following, usingFigure 2 And Figure 3 A specific example of splitting the light of the etalon element 30 and changing the wavelength of the split light to an arbitrary wavelength is described. Figure 2 is a schematic diagram showing the etalon element 30 and the detector 40. The etalon element 30 includes a half mirror 31, a half mirror 32, and a driving device 33. The half mirror 31 and the half mirror 32 are disposed at positions facing each other with a distance d. The distance d is called an air gap.

[0046] The half mirror 31 reflects a part of the cathode luminescence CL2 reflected by the mirror 20 and transmits a part of the cathode luminescence CL2 reflected by the mirror 20. The half mirror 32 reflects a part of the cathode luminescence transmitted through the half mirror 31 and transmits a part of the cathode luminescence transmitted through the half mirror 31. The detector 40 detects the cathode luminescence CL3 transmitted through the half mirror 32.

[0047] As shown in Figure 2 , the etalon element 30 is provided with the driving device 33 disposed so as to surround the half mirror 32 and the half mirror 31. The driving device 33 is configured to be able to move the position of the half mirror 32 or the position of the half mirror 31.

[0048] The driving device 33 of Embodiment 1 is configured to include a piezoelectric element. The piezoelectric element is an element that is driven using a piezoelectric effect. The piezoelectric element included in the driving device 33 is pressed by applying a voltage thereto, whereby the distance d changes. That is, the control device 50 is able to change the distance d by adjusting the voltage value applied to the piezoelectric element included in the driving device 33.

[0049] Thus, the control device 50 is able to adjust the wavelength of the cathode luminescence CL3 to be passed through the etalon element 30. Furthermore, the driving device 33 can also change the distance d without using a piezoelectric element. For example, the driving device 33 can also be a structure including a motor or an electromagnetic actuator, or the like.

[0050] Figure 3 is a diagram showing the multiple interference of the etalon element 30. As shown in Figure 3 , the cathode luminescence CL2 reflected by the mirror 20 is incident on the half mirror 31. A part of the cathode luminescence CL2 transmits through the half mirror 31. In Figure 3 , the cathode luminescence CL2 that has transmitted through the half mirror 31 is denoted as cathode luminescence CLg.

[0051] The cathodoluminescence CLg is repeatedly reflected between the half mirror 31 and the half mirror 32. The half mirror 31 and the half mirror 32 interfere with the cathodoluminescence CLg of the integer multiple of the wavelength by the distance d. By the interference, the cathodoluminescence CLg of the specific wavelength is enhanced each other. Thus, the etalon element 30 can transmit only the cathodoluminescence CL3 of the specific wavelength from the half mirror 32.

[0052] Figure 4 FIG. 6 is a diagram showing an example of a display of the intensity of the cathodoluminescence emitted from the sample Sp1 in Embodiment 1. As described above, the control device 50 calculates the intensity of the cathodoluminescence of the position of the sample Sp1 irradiated with the electron beam EBl. The control device 50 forms an image showing the distribution of the intensity of the cathodoluminescence of the entire sample Sp1 by scanning the entire sample Sp1 with the electron beam EBl.

[0053] In Figure 4 FIG. 6 shows an example in which the control device 50 displays the formed image Im1 on the display 60. As Figure 4 indicated in FIG. 6, the sample Sp1 is displayed in the display 60 as viewed from the positive direction of the Z axis.

[0054] In the cathodoluminescence spectrometer 100 in Embodiment 1, the voltage value applied to the scanning coil 13 is adjusted to change the magnetic field, and thus the electron beam EBl is scanned. Thus, the electron beam EBl is incident on the entire sample Sp1 as viewed from the positive direction of the Z axis.

[0055] The control device 50 forms the image Im1 using the position at which the electron beam EBl is incident and the intensity of the cathodoluminescence at the position. In Figure 4 FIG. 6, the area Arl indicated by a solid line and the area Ar2 indicated by a broken line are shown in the image Im1. The area Arl is an area in which the intensity of the cathodoluminescence is higher than that of the area Ar2. In addition, the area in the image Im1 other than the areas Arl and Ar2 is an area that is not scanned or in which the intensity of the cathodoluminescence is not detected. The control device 50 can also display the image Im1 showing the intensity of the cathodoluminescence superimposed on the image of the sample Sp1 obtained by detecting secondary electrons.

[0056] Thus, in the case of the cathodoluminescence spectrometer 100 in Embodiment 1, it is possible to visually display the intensity of the cathodoluminescence generated when the sample Sp1 is irradiated with the electron beam EBl using the etalon element 30. As described above, the space required when the etalon element 30 is disposed is smaller than the space required when the spectrometer crystal is disposed.

[0057] Thus, in the cathodoluminescence spectroscopic device 100 of Embodiment 1, miniaturization of the spectroscope for spectroscopically analyzing the cathodoluminescence can be achieved. As a result, miniaturization of the cathodoluminescence spectroscopic device 100 can be achieved or other devices or the like can be arranged inside the cathodoluminescence spectroscopic device 100. In addition, the etalon element 30 is less expensive than the spectroscopic crystal, and thus the cost of the cathodoluminescence spectroscopic device 100 as a whole can be reduced.

[0058] In a case where spectroscopy is performed using a spectroscopic crystal, the wavelength of the cathodoluminescence spectroscopically analyzed by the spectroscopic crystal varies depending on the angle at which the cathodoluminescence is incident on the spectroscopic crystal. Thus, in order to obtain the spectrum of each wavelength, an operation of changing the angle of the spectroscopic crystal needs to be performed each time of detection. In order to accurately perform the operation of changing the angle of the spectroscopic crystal, zero-point correction needs to be appropriately performed, and thus the total time required for spectroscopy can be long.

[0059] On the other hand, in the case of the cathodoluminescence spectroscopic device 100 of Embodiment 1, the wavelength after spectroscopy can be easily changed by adjusting the voltage applied to the piezoelectric element included in the driving device 33. That is, in the case of the cathodoluminescence spectroscopic device 100 of Embodiment 1, the time required for analyzing the cathodoluminescence can be reduced as compared with the case where a spectroscopic crystal is used.

[0060] [Embodiment 2]

[0061] In the case of the cathodoluminescence spectroscopic device 100 of Embodiment 1, a structure in which the emission intensity of the cathodoluminescence of the entire surface of the sample Sp1 is detected by scanning the electron beam EB1 is described. In Embodiment 2, a structure in which an image representing the emission intensity of the cathodoluminescence is formed without scanning the electron beam EB1 is described. Furthermore, in the cathodoluminescence spectroscopic device 100A of Embodiment 2, a description is not repeated for the structures common to the cathodoluminescence spectroscopic device 100 of Embodiment 1.

[0062] Figure 5 FIG. 1 is a diagram schematically showing the cathodoluminescence spectroscopic device 100A of Embodiment 2. The same sample Sp1 as in Embodiment 1 is placed on the sample stage 15 of Embodiment 2. As shown in FIG. 1, in the cathodoluminescence spectroscopic device 100A of Embodiment 2, the detector 40A that detects the cathodoluminescence CL3 is implemented as a CCD (Charge Coupled Device). The detector 40A as the CCD has a plurality of light-receiving elements. The detector 40A and the etalon element 30 can also be integrally provided. Figure 5

[0063] ​In addition, in Embodiment 2, the electron beam EB2 emitted from the electron source 11 is not reduced in diameter to be small by the objective lens 14 but is incident on the sample Sp1 in a state of having a width Wd. Thereby, the electron beam EB2 is irradiated to a fixed region of the surface on the positive direction side of the Z axis of the sample Sp1. Hereinafter, the region irradiated with the electron beam EB2 is referred to as an "irradiation region". The area of the irradiation region can be controlled to be a size corresponding to the optical condensing system by the electron gun optical system. The irradiation region has an area of about 0.16 mm2, for example.

[0064] Figure 6 is a perspective view of the sample Sp1 irradiated with the electron beam EB2. In Figure 6 , the electron beam EB2 irradiates the irradiation region Fc1 of the surface of the sample Sp1. The irradiation region Fc1 has a circular shape having a diameter of the width Wd. The point Cp represents the center of the circular-shaped irradiation region Fc1.

[0065] As shown in Figure 6 , the irradiation region Fc1 includes the region Fa1, the region Fa2, and the region Fa3. The cathodoluminescence CL11, CL12, CL13 is emitted from the regions Fa1, Fa2, Fa3, respectively, by the irradiation with the electron beam EB2. The cathodoluminescence CL11, CL12, CL13 is reflected by the mirror 20 as the cathodoluminescence CL21, CL22, CL23 and is condensed toward the etalon element 30.

[0066] Figure 7 is a perspective view of the etalon element 30 and the detector 40A which is a CCD. As shown in Figure 7 , the cathodoluminescence CL21, CL22, CL23 is incident on the half mirror 31 of the etalon element 30. By multiple interference, the cathodoluminescence CL31, CL32, CL33 of a specific wavelength is transmitted through the half mirror 32. The detector 40A which is a CCD has a plurality of light-receiving elements including the light-receiving elements LE1, LE2, LE3.

[0067] The cathodoluminescence CL31 is detected by the light-receiving element LE1. The cathodoluminescence CL32 is detected by the light-receiving element LE2. The cathodoluminescence CL33 is detected by the light-receiving element LE3. The detection value of the light-receiving element LE1 represents the luminous intensity of the cathodoluminescence of the region Fa1. The detection value of the light-receiving element LE2 represents the luminous intensity of the cathodoluminescence of the region Fa2. The detection value of the light-receiving element LE3 represents the luminous intensity of the cathodoluminescence of the region Fa3. In this way, the cathodoluminescence spectrometer 100A of Embodiment 2 can form an image representing the luminous intensity of the cathodoluminescence of the entire sample Sp1 even without scanning the electron gun 10.

[0068] Figure 8is a drawing showing an example of a display of the emission intensity of the cathodoluminescence emitted from the sample Sp1 of Embodiment 2. The display 60 displays an image Im2. The image Im2 is an image formed by the control device 50 using the detection results of the detector 40A that is a CCD. The region Fdl in the image Im2 is a region corresponding to the irradiation region Fcl in Figure 6 . In addition, the regions Fbl, Fb2, Fb3 in the image Im2 respectively correspond to the regions Fal, Fa2, Fa3 in Figure 6 .

[0069] Figure 8 The region Arl in Figure 4 corresponds to the region Arl in Figure 8 . The region Ar2 in Figure 4 corresponds to the region Ar2 in . That is, the region Arl is a region in which the emission intensity is the highest, and the region Ar2 is a region in which the emission intensity is lower than the region Arl. Also, the region Ar3 in the region Fdl, which is not the region Arl and the region Ar2, is a region in which the cathodoluminescence emission is not detected. Thus, the user can observe the image Im2 to grasp that the emission intensity of the detected cathodoluminescence becomes higher in the order of the light receiving elements LEl, LE2, LE3.

[0070] Thus, in Embodiment 2 also, the miniaturization of the spectroscope for spectrally separating the cathodoluminescence and the reduction of the cost can be achieved in the cathodoluminescence spectrometer 100A by using the etalon element 30 to spectrally separate. In addition, as explained above, the etalon element 30 performs the wavelength scanning of the light using the driving device 33 including the piezoelectric element. Therefore, the analysis time in the case of using the etalon element 30 is shorter than that in the case of using the spectroscope that requires the change of the position of the spectrometric crystal. That is, the analysis time can be shortened also in Embodiment 2. Also, the cathodoluminescence spectrometer 100A of Embodiment 2 forms the image Im2 using the CCD having a plurality of light receiving elements and the etalon element 30 capable of spectrally separating a plurality of cathodoluminescences at the same time. Thus, the control device 50 can form the image Im2 representing the emission intensity of the cathodoluminescence emitted from the sample Sp1 even without causing the electron gun 10 to scan, and can reduce the time required for the image formation. In addition, by integrating the detector 40A that is a CCD and the etalon element 30, the cathodoluminescence spectrometer 100A can be further miniaturized.

[0071] And, since the electron beam EB2 does not need to be scanned, Energy Dispersive X-ray Spectroscopy or Wavelength Dispersive X-ray Spectroscopy and cathodoluminescence analysis can be performed simultaneously. In addition, the spectrum of the cathodoluminescence CL3 can be detected by each light-receiving element included in the detector 40A as a CCD. That is, the cathodoluminescence spectrometer 100A of Embodiment 2 can display the regions Ar1 to Ar3 differently not only according to the luminescence intensity but also according to the wavelength.

[0072] Next, using Figures 9-11 An example in which the regions Ar1 to Ar3 are displayed differently according to the wavelength will be described. The control device 50 causes the distance d between the half-mirror 31 and the half-mirror 32 of the etalon element 30 to change while causing the detector 40A to detect the cathodoluminescence CL3. Thus, each light-receiving element of the detector 40A detects the luminescence intensity of the cathodoluminescence CL3 of a plurality of wavelengths. The plurality of wavelengths can be, for example, wavelengths between 200 nm and 1300 nm. Figure 9 is a graph showing an example of the spectrum of the light-receiving element LE3 corresponding to the region Ar1 of Figure 8 As shown in Figure 9 , the light-receiving element LE3 detects the cathodoluminescence CL3 of a luminescence intensity exceeding the threshold value Th at a wavelength around 400 nm.

[0073] Next, Figure 10 is a graph showing an example of the spectrum of the light-receiving element LE2 corresponding to the region Ar2 of Figure 8 As shown in Figure 10 , the light-receiving element LE2 detects the cathodoluminescence CL3 of a luminescence intensity exceeding the threshold value Th at a wavelength around 1000 nm. Also, Figure 11 is a graph showing an example of the spectrum of the light-receiving element LE1 corresponding to the region Ar3 of Figure 8 As shown in Figure 11 , the light-receiving element LE1 does not detect the cathodoluminescence CL3 of a luminescence intensity exceeding the threshold value Th at wavelengths between 200 nm and 1300 nm. The threshold value Th can be determined in advance according to the sensitivity of the detector 40A as a CCD or the like.

[0074] Thus, the cathodoluminescence spectrometer 100A of Embodiment 2 can detect the spectrum of the cathodoluminescence CL3 by each light-receiving element possessed by the detector 40A. Therefore, the cathodoluminescence spectrometer 100A of Embodiment 2 can display the regions Ar1 to Ar3 corresponding to each light-receiving element differently not only according to the luminescence intensity but also according to the wavelength when displaying the image Im2. Specifically, the control device 50 causes the display device 20 to display the regions Ar1 to Ar3 corresponding to each light-receiving element differently according to the luminescence intensity and the wavelength.Figure 8 The image Im2 shown on the display 60 is displayed with colors labeled corresponding to the wavelengths detected.

[0075] For example, the control device 50 displays a region corresponding to the light-receiving element LE3 that detected a high emission intensity at a wavelength around 400 nm in blue, and displays a region corresponding to the light-receiving element LE2 that detected a high emission intensity at a wavelength of 1000 nm in red. In addition, the control device 50 can also change the shade of the color displayed depending on the emission intensity in order to distinguish the light-receiving elements that detected cathodoluminescence exceeding the threshold value Th at the same wavelength. In this way, by varying the display method of the region corresponding to the light-receiving element depending on the emission intensity and the wavelength, the cathodoluminescence spectrometer 100A of Embodiment 2 enables the user to easily grasp the difference in emission intensity and wavelength at each position on the sample Sp1.

[0076] [Embodiment 3]

[0077] In the cathodoluminescence spectrometer 100A of Embodiment 2, a configuration in which the emission intensity of cathodoluminescence is detected using the detector 40A including a plurality of light-receiving elements without scanning the electron beam EB2 was explained. In Embodiment 3, a configuration in which the configuration of the electron gun 10 is changed is explained. Furthermore, in the cathodoluminescence spectrometer 100B of Embodiment 3, the configuration that is repeated with the cathodoluminescence spectrometer 100A of Embodiment 2 is not repeated.

[0078] Figure 12 is a diagram showing an outline of the cathodoluminescence spectrometer 100B of Embodiment 3. As Figure 12 shown, the electron gun 10 is disposed at a position separated from the sample Sp1 in the X-axis direction. In Embodiment 2, the incident angle of the electron beam EB2 incident to the sample Sp1 was 0 degrees, but in Embodiment 3, the electron beam EB is incident to the sample Sp1 at an angle with an incident angle greater than 0 degrees. In Figure 12 , the condenser lens 25 is disposed between the mirror 20 and the sample Sp1.

[0079] Figure 13 is a diagram for explaining the incident angle of the electron beam EB2 of Embodiment 3. In Embodiment 2 and Embodiment 3, the face on the positive direction side of the Z-axis of the sample Sp1 placed on the sample stage 15 is parallel to the face of the sample stage 15. As Figure 6 shown, the electron beam EB2 of Embodiment 2 is incident to the irradiation region Fc1. In Embodiment 2, the electron beam EB2 at the point Cp of the irradiation region Fc1 is perpendicularly incident from the normal direction of the sample stage 15. That is, the incident angle is 0 degrees.

[0080] On the other hand, as Figure 13As shown, the electron beam EB2 irradiating the point Cp as the center of the irradiation region Fc1 is incident on the sample Sp1 at an incident angle θ. The incident angle θ is an angle greater than 0 degrees and less than 90 degrees.

[0081] In this manner, in Embodiment 3, the use of the etalon element 30 for spectrometry enables miniaturization of the spectrometer used for spectrometry of cathode luminescence in the cathode luminescence spectrometer 100B, thereby reducing costs and shortening analysis time. Furthermore, when the electron beam EB2 is not scanned, the electron beam EB2 does not need to irradiate the sample stage 15 perpendicularly. Therefore, in Embodiment 3, the electron gun 10 irradiates the sample Sp1 at an angle greater than 0 degrees and less than 90 degrees. This increases the degree of freedom in the configuration of the electron gun 10. Furthermore, the reflector 20 does not need to have an opening 20a.

[0082] [Implementation 4]

[0083] In the cathodoluminescence spectrometers 100, 100A, and 100B of Embodiments 1 to 3, a configuration in which the etalon element 30 is used to detect the intensity of cathodoluminescence is described. In Embodiment 4, a configuration including a spectrometer in addition to the etalon element 30 is described. Furthermore, in the cathodoluminescence spectrometer 100C of Embodiment 4, the configuration that overlaps with the cathodoluminescence spectrometer 100 of Embodiment 1 is not described again.

[0084] Figure 14 This is a diagram showing the configuration of a cathodoluminescence spectrometer 100C according to a fourth embodiment. Figure 14 (A) shows an example of spectrometry using the etalon element 30. Figure 14 (B) shows an example of spectrometry using the spectroscopic crystal 35 .

[0085] like Figure 14 As shown in FIG. 1A , the cathodoluminescence spectrometer 100C includes not only the etalon element 30 but also a spectroscopic crystal 35 . The spectroscopic crystal 35 is configured to reflect cathode luminescence CL3 of a specific wavelength among the cathode luminescence CL2 focused by the reflective mirror 20 .

[0086] like Figure 14As shown in (A), the cathodoluminescence spectrometer 100C further has a switching mechanism 80. The switching mechanism 80 is configured to be able to switch the condensing destination of the mirror 20 between the etalon element 30 and the spectrometric crystal 35. The switching mechanism 80 can be, for example, a motor or the like for changing the position of the etalon element 30 and the spectrometric crystal 35, or a motor or the like for changing the angle of the mirror 20. The switching mechanism 80 is electrically connected to the control device 50. The control device 50 controls the switching mechanism 80 to switch the condensing destination of the mirror 20.

[0087] In Figure 14 (A) of FIG. 10, the condensing destination of the mirror 20 is the etalon element 30. The detector 40 detects the intensity of the cathodoluminescence CL3 after the spectrometry by the etalon element 30. The control device 50 forms an image based on the detection result of the detector 40. The image formed based on the cathodoluminescence CL3 after the spectrometry using the etalon element 30 corresponds to the "first image" of the present disclosure.

[0088] In Figure 14 (B) of FIG. 10, the condensing destination of the mirror 20 is switched from the etalon element 30 to the spectrometric crystal 35. The detector 40 detects the intensity of the cathodoluminescence CL3 after the spectrometry by the spectrometric crystal 35. The control device 50 forms an image based on the detection result of the detector 40. The image formed based on the cathodoluminescence CL3 after the spectrometry using the spectrometric crystal 35 corresponds to the "second image" of the present disclosure. The control device 50 can also switch the condensing destination of the mirror 20 from the spectrometric crystal 35 to the etalon element 30.

[0089] <Regarding Wavelength Resolution>

[0090] Figure 15 FIG. 11 is a graph showing the spectrum in the case where the etalon element 30 is used. Figure 16 FIG. 12 is a graph showing the spectrum in the case where the spectrometric crystal 35 is used. In Figure 15 and Figure 16 FIGS. 13 and 14 show the results obtained by analyzing the cathodoluminescence of the same sample.

[0091] As shown in Figure 15 and Figure 16 , the shape of the waveform showing the spectrum shown as the region Ar3 is different. Specifically, in the case where the etalon element 30 is used, a high intensity is shown in a wide wavelength range within the region Rg1. On the other hand, in the case where the spectrometric crystal 35 is used, a high intensity is shown in a narrower wavelength range than in the case where the etalon element 30 is used within the region Rg2. That is, the wavelength resolution of the spectrometric crystal 35 is higher than the wavelength resolution of the etalon element 30.

[0092] In summary, analysis using the etalon element 30 enables analysis in a shorter time than analysis using the spectroscopic crystal 35, but since the wavelength resolution of the etalon element 30 is lower than the wavelength resolution of the spectroscopic crystal 35, accurate detection results cannot be obtained in some cases.

[0093] Therefore, in Embodiment 4, the control device 50 performs analysis using the spectroscopic crystal 35 after analysis using the etalon element 30. Figure 17 is a flowchart showing analysis processing in which the etalon element 30 is switched to the spectroscopic crystal 35. As shown in (A) of Figure 14 As shown in (A) of

[0094] The control device 50 forms an image based on the cathodoluminescence CL3 after spectroscopy using the etalon element 30, and displays the image on the display 60 (step S2). At this time, it is assumed that a user who confirms the image displayed on the display 60 desires to more accurately detect the emission intensity of the cathodoluminescence. The cathodoluminescence spectroscopy device 100C of Embodiment 4 can receive a command to detect after switching to the spectroscopic crystal 35 from the input device 70 in a case where the user desires to more accurately detect the emission intensity.

[0095] The cathodoluminescence spectroscopy device 100C can also receive a command to change the region in which the electron beam EBl is irradiated or scanned in addition to receiving a command to detect after switching to the spectroscopic crystal 35. That is, in a case where it is desired to detect only a part of the image displayed in step S2 by the spectroscopic crystal 35, the user can select a detection region from the surface of the sample Sp1.

[0096] The control device 50 determines whether a command to switch to the spectroscopic crystal 35 is received from the user (step S3). The control device 50 determines whether a command to end the analysis processing is received in a case where it is determined that the command to switch is not received (NO in step S3). The control device 50 ends the analysis processing in a case where it is determined that the command to end the analysis processing is received (YES in step S4). The control device 50 repeats the processing of step S3 in a case where it is determined that the command to end the analysis processing is not received (NO in step S4).

[0097] If the control device 50 determines that a switching command has been received ("Yes" in step S3), it switches the focusing destination of the reflector 20 to the spectroscopic crystal 35 (step S5). In other words, the control device 50 controls the switching mechanism 80. At this time, if the detection area is received, the control device 50 controls the angle of the electron beam EB1 caused by the scanning coil 13 and the reduction performed by the objective lens 14 to change the area where the electron beam EB1 is incident on the sample Sp1.

[0098] like Figure 14 As shown in (B), the control device 50 performs spectroscopic analysis using the spectroscopic crystal 35 (step S6). When the spectroscopic crystal 35 is used, spectroscopic analysis with high wavelength resolution can be performed. The control device 50 forms an image based on the cathode luminescence CL3 obtained by spectroscopic analysis using the spectroscopic crystal 35, and displays the image on the display 60 (step S7).

[0099] Thus, in Embodiment 4, the analysis time can also be shortened in the cathodoluminescence spectrometer 100A by using the etalon element 30 for spectrometry. Furthermore, in Embodiment 4, a spectroscopic crystal 35 is provided, which enables switching of the focusing destination of the reflector 20 according to the intended use. Specifically, in Embodiment 4, after analysis using the etalon element 30, which enables rapid analysis, analysis can be performed on a portion requiring more accurate analysis using the spectroscopic crystal 35, thereby enabling efficient analysis.

[0100] [Modification]

[0101] (1) In Embodiment 1, an example in which the etalon element 30 includes a drive device has been described. However, the cathodoluminescence spectroscopic apparatus 100 may also include an etalon element 30 in which the distance d between the half mirror 31 and the half mirror 32 is fixed. The cathodoluminescence spectroscopic apparatus 100 may also include a plurality of etalon elements 30 having different distances d, and the switching mechanism 80 may be used to switch the focusing destination among the plurality of etalon elements 30.

[0102] (2) In Embodiment 2, an example of displaying image Im2 based on the intensity or wavelength of cathode luminescence CL3 detected by detector 40A as a CCD is described. In a modified example, a configuration is described in which control device 50 superimposes another image on image Im2 and displays it on display 60.

[0103] Figure 18This figure illustrates image superposition. As described in Embodiment 1, the control device 50 can superimpose the image of the sample Sp1 obtained by detecting secondary electrons on the image Im1 for display. Furthermore, in Embodiment 2, the control device 50 can similarly superimpose the image obtained by detecting secondary electrons on the image Im2 for display.

[0104] In the second embodiment, a CCD is used as detector 40A. The CCD can detect not only the reflection of cathode luminescence but also the reflected light from the sample Sp1 when ordinary visible light is used as illumination. The control device 50 of the second embodiment can also superimpose the image of the sample Sp1 obtained by detecting the reflected light when ordinary visible light is used as illumination on the image Im2 for display.

[0105] Figure 18 The image Im3 shown in (A) is an image obtained by detecting secondary electrons or an image obtained by detecting reflected light when ordinary visible light is used as illumination. That is, the image is obtained without using cathode luminescence. Figure 18 The image Im3 shown in (A).

[0106] Then, in Figure 18 (B) shows an image Im4 when the detector 40A as a CCD detects the cathode luminescence CL2 before being split by the etalon element 30. In other words, Figure 18 The image Im4 of (B) is obtained by Figure 5 The image Im4 is obtained by detecting the cathode luminescence CL2 by the detector 40A in a state where the etalon element 30 is removed. The image Im4 shows a region Ar4 where the detector 40A detects the emission of the cathode luminescence CL2.

[0107] The cathode luminescence CL2 before being split by the etalon element 30 includes cathode luminescence having more wavelengths than the cathode luminescence CL3 after being split by the etalon element 30. Figure 9 In the description, the spectrum of the cathode luminescence CL3 is described when the etalon element 30 is used to separate the light into wavelengths between 200 nm and 1300 nm. However, the cathode luminescence CL2 can also include cathode luminescence with wavelengths other than 200 nm to 1300 nm. Therefore, the region Ar4 includes the regions Ar1 and Ar2.

[0108] The control device 50 can superimpose the image Im3 and the image Im4 on the Figure 8 The image Im2. Figure 18 The image Im5 in (C) is Figure 18 (A) Image Im3 and Figure 18 The image of (B) Im4 is superimposed onFigure 8 The image after the image Im2. Figure 18 In (C), image Im3 acquired without using cathodoluminescence is superimposed on image Im2 obtained by detecting cathodoluminescence CL3. Thus, the cathodoluminescence spectrometer 100A enables the user to easily understand where in the specimen Sp1 the cathodoluminescence CL3 is emitted after spectrometry, using an image of the specimen Sp1 obtained based on reflection of secondary electrons or visible light.

[0109] And, in Figure 18 In (C), image Im4 obtained by detecting cathode luminescence CL2 before spectroscopy is superimposed on image Im2 obtained by detecting cathode luminescence CL3 after spectroscopy. This allows the user to easily understand the difference in luminescence intensity between cathode luminescence CL2 before spectroscopy and cathode luminescence CL3 after spectroscopy.

[0110] For example, if the intensity of the cathode luminescence CL3 after spectrophotometry is low and only the cathode luminescence CL3 after spectrophotometry is displayed on the display 60, the user may perceive that the cathode luminescence itself is not emitting. However, in the case of the cathode luminescence spectrometry device 100A of the modified example, by superimposing image Im4 and image Im2, the area Ar4 where the cathode luminescence CL2 before spectrophotometry is emitting can be displayed on the display 60, thereby preventing the user from overlooking that the cathode luminescence itself is emitting. Furthermore, image Im5 can be an image formed by superimposing only images Im2 and Im3, or an image formed by superimposing only images Im2 and Im4.

[0111] (3) In the fourth embodiment, a configuration has been described in which the switching mechanism 80 switches the light-converging destination of the reflector 20 between the spectroscopic crystal 35 and the etalon element 30. However, the cathode luminescence reflected by the reflector 20 may be simultaneously converged to the spectroscopic crystal 35 and the etalon element 30. For example, a configuration may be adopted in which a semi-transparent mirror is further provided at the light-converging destination of the reflector 20, and the cathode luminescence from the reflector 20 is branched by the semi-transparent mirror to the spectroscopic crystal 35 and the etalon element 30, thereby converging the cathode luminescence simultaneously.

[0112] [Way]

[0113] It will be understood by those skilled in the art that the above-described multiple exemplary embodiments are specific examples of the following aspects.

[0114] (Item 1) A cathodoluminescence spectrometer according to one embodiment includes: an electron gun that irradiates a sample with an electron beam; a focusing mechanism that focuses cathode luminescence emitted from the sample by irradiating the sample with the electron beam; a spectrometer configured to split the cathode luminescence focused by the focusing mechanism; a detector that detects the intensity of the cathode luminescence split by the spectrometer; and a control device that receives the detection result from the detector and controls the cathodoluminescence spectrometer. The spectrometer includes a first half mirror and a second half mirror disposed opposite the first half mirror. The first half mirror reflects a portion of the cathode luminescence focused by the focusing mechanism and transmits a portion of the cathode luminescence focused by the focusing mechanism. The second half mirror reflects a portion of the cathode luminescence that has passed through the first half mirror and transmits a portion of the cathode luminescence that has passed through the first half mirror. The first and second half mirrors cause interference between the cathode luminescence between the first and second half mirrors, thereby allowing cathode luminescence of a specific wavelength to pass through the second half mirror. The detector detects the intensity of the cathode luminescence that has passed through the second half mirror.

[0115] According to the spectroscopic apparatus described in the first item, by performing spectrometry using the etalon element 30 , the analysis time can be shortened in the cathodoluminescence spectroscopic apparatus 100A.

[0116] (Item 2) In the cathode luminescence spectrometer according to Item 1, the detector includes a first light receiving element and a second light receiving element. The electron gun irradiates an irradiation area on the surface of the sample with an electron beam. The spectrometer spectrometer spectrometer spectrometers the first cathode luminescence emitted from a first area within the irradiation area and the second cathode luminescence emitted from a second area within the irradiation area that is different from the first area. The first light receiving element receives the first cathode luminescence spectrometered by the spectrometer. The second light receiving element receives the second cathode luminescence spectrometered by the spectrometer.

[0117] According to the spectroscopic apparatus described in the second aspect, it is possible to form an image showing the intensity of cathode luminescence of the entire sample Sp1 without scanning the electron gun 10 .

[0118] (Item 3) In the cathode luminescence spectrometer according to Item 2, an incident angle of the electron beam when entering the sample is larger than 0 degrees and smaller than 90 degrees.

[0119] According to the spectroscopic device described in the third aspect, the degree of freedom in arrangement of the electron gun 10 is improved.

[0120] (Item 4) In the cathode luminescence spectroscopic device according to any one of Items 1 to 3, the spectroscopic element further includes a driving device that changes the distance between the first half mirror and the second half mirror.

[0121] According to the fourth aspect, the single light splitting element can split light into a plurality of wavelengths.

[0122] (Fifth aspect) In the cathodoluminescence light splitting device according to the fourth aspect, the driving device is configured to include a piezoelectric element.

[0123] According to the fifth aspect, the distance between the first half mirror and the second half mirror can be accurately and quickly changed by the piezoelectric element.

[0124] (Sixth aspect) In the cathodoluminescence light splitting device according to any one of the first to fifth aspects, further comprising: a light splitting crystal configured to reflect a specific wavelength of the cathodoluminescence after being condensed by the condensing mechanism; and a switching mechanism that switches a condensing destination of the condensing mechanism to the light splitting crystal or the light splitting element.

[0125] According to the sixth aspect, the light splitter can be easily switched according to the use.

[0126] (Seventh aspect) In the cathodoluminescence light splitting device according to the sixth aspect, the control device forms a first image based on the cathodoluminescence after being split by the light splitting element, and the control device displays a second image based on the cathodoluminescence after being split by the light splitting crystal when a command to switch to the light splitting crystal is received.

[0127] According to the seventh aspect, the light can be split by the light splitting crystal having a high wavelength resolution after being split by the light splitting element having a short analysis time.

[0128] Furthermore, with respect to the above-described embodiments and modifications, combinations not mentioned in the specification are included, and the structures described in the embodiments are appropriately combined within a range where no adverse effects or contradictions occur, from the beginning of the application.

[0129] Embodiments of the present application have been described, but it should be considered that the embodiments disclosed this time are illustrative in all respects, not restrictive. The scope of the present application is shown by the claims, and is intended to include all modifications within the meaning and range equivalent to the claims.

Claims

1. A cathodoluminescence spectrometer comprising: an electron gun that irradiates the sample with an electron beam; a focusing mechanism for focusing cathode luminescence emitted from the sample by irradiating the sample with the electron beam; a spectroscopic element configured to split the cathode luminescence focused by the focusing mechanism; a detector for detecting the intensity of the cathode luminescence after being split by the spectroscopic element; a spectroscopic crystal configured to reflect cathode luminescence having a specific wavelength among the cathode luminescence focused by the focusing mechanism; a switching mechanism that switches the focusing destination of the focusing mechanism to the spectroscopic crystal or the spectroscopic element; and a control device that receives the detection result from the detector to control the cathode luminescence spectrometer, in, The light splitting element includes a first half-reflective mirror and a second half-reflective mirror arranged at a position facing the first half-reflective mirror. The first half mirror reflects a portion of the cathode luminescence focused by the focusing mechanism and transmits a portion of the cathode luminescence focused by the focusing mechanism. The second half mirror reflects a portion of the cathode luminescence that has passed through the first half mirror, and transmits a portion of the cathode luminescence that has passed through the first half mirror. The first half mirror and the second half mirror cause interference between the cathode luminescence of the first half mirror and the second half mirror, thereby allowing cathode luminescence of a specific wavelength to pass through the second half mirror. The detector detects the intensity of the cathode luminescence transmitted through the second half mirror.

2. The cathodoluminescence spectrometer according to claim 1, wherein: The detector includes a first light receiving element and a second light receiving element, The electron gun irradiates an irradiation area on the surface of the sample with an electron beam. The spectroscopic element is configured to split first cathode luminescence emitted from a first region in the irradiation region and to split second cathode luminescence emitted from a second region in the irradiation region that is different from the first region. The first light receiving element receives the first cathode light after being split by the light splitting element. The second light receiving element receives the second cathode luminescence that has been split by the light splitting element.

3. The cathodoluminescence spectrometer according to claim 2, wherein: The incident angle of the electron beam when incident on the sample is greater than 0 degrees and less than 90 degrees.

4. The cathodoluminescence spectrometer according to any one of claims 1 to 3, wherein: The spectroscopic element further includes a driving device that changes the distance between the first half mirror and the second half mirror.

5. The cathodoluminescence spectrometer according to claim 4, wherein: The driving device is configured to include a piezoelectric element.

6. The cathodoluminescence spectrometer according to any one of claims 1 to 3, wherein: The control device forms a first image based on the cathode luminescence obtained by the spectroscopic element. When receiving the command to switch to the spectroscopic crystal, the control device displays a second image based on cathode luminescence obtained by spectroscopic analysis by the spectroscopic crystal.

7. The cathodoluminescence spectrometer according to claim 4, wherein: The control device forms a first image based on the cathode luminescence obtained by the spectroscopic element. When receiving the command to switch to the spectroscopic crystal, the control device displays a second image based on cathode luminescence obtained by spectroscopic analysis by the spectroscopic crystal.

8. The cathodoluminescence spectrometer according to claim 5, wherein: The control device forms a first image based on the cathode luminescence obtained by the spectroscopic element. When receiving the command to switch to the spectroscopic crystal, the control device displays a second image based on cathode luminescence obtained by spectroscopic analysis by the spectroscopic crystal.

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