Cathodoluminescence spectrometer

Abstract

To miniaturize a spectroscope for dividing a cathode luminescence in a cathode luminescence spectral instrument.SOLUTION: A cathode luminescence spectral instrument 100 disclosed in the present invention, comprises an electron gun 10, a mirror 20, an etalon element 30, a detector 40, and a control apparatus 50. The etalon element 30 includes a first mirror and a second mirror. The second mirror is provided in a position opposite to the first mirror. The first mirror reflects a part of cathode luminescence CL2 collected by the mirror 20, and transmits a part thereof. The second mirror reflects a part of cathode luminescence transmitting the first mirror, and transmits a part thereof. The first mirror and the second mirror cause interfere of cathode luminescence between the first mirror and the second mirror, and transmits cathode luminescence CL3 of a specific wavelength from the second mirror. The detector 40 detects a strength of the cathode luminescence CL3 transmitting the second mirror.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a cathodoluminescence spectroscopy apparatus. [Background technology]

[0002] Conventionally, there is known a technique for detecting cathodoluminescence emitted from a sample and obtaining information such as the distribution of lattice defects or impurities in the sample.

[0003] For example, Japanese Patent Laid-Open Publication No. 2000-206046 (Patent Document 1) discloses a cathode luminescence spectroscopic device that generates cathode luminescence by irradiating a sample with an electron beam and disperses the cathode luminescence using a dispersive crystal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2000-206046 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the cathode luminescence spectrometer of Patent Document 1, since a dispersing crystal is used as a spectrometer, the dispersing crystal itself needs to be placed inside the cathode luminescence spectrometer. Therefore, the cathode luminescence spectrometer needs to have a space for placing the dispersing crystal, which may increase the size of the spectrometer. As a result, there is a concern that the cathode luminescence spectrometer itself will also increase in size.

[0006] The present invention has been made to solve the above problems, and an object of the present invention is to reduce the size of a spectroscope for dispersing cathode luminescence in a cathode luminescence spectroscopic device. [Means for solving the problem]

[0007] The cathodoluminescence spectroscopic device of the present disclosure includes an electron gun, a focusing mechanism, a spectroscopic element, a detector, and a control device. The electron gun irradiates an electron beam onto a sample. The focusing mechanism focuses cathodoluminescence emitted from the sample by irradiating the sample with the electron beam. The spectroscopic element is configured to be able to disperse the cathodoluminescence focused by the focusing mechanism. The detector detects the intensity of the cathodoluminescence dispersed by the spectroscopic element. The control device receives the detection result from the detector and controls the cathodoluminescence spectroscopic device. The spectroscopic element includes a first mirror and a second mirror. The second mirror is provided at a position opposite to the first mirror. The first mirror reflects a portion of the cathodoluminescence focused by the focusing mechanism and transmits a portion of it. The second mirror reflects a portion of the cathodoluminescence that has transmitted through the first mirror and transmits a portion of it. The first and second mirrors interfere with cathodoluminescence between the first and second mirrors to transmit cathodoluminescence of a particular wavelength from the second mirror, and the detector detects the intensity of the cathodoluminescence transmitted through the second mirror. Effect of the Invention

[0008] The cathode luminescence spectroscopic device according to the present disclosure includes a spectroscopic element that disperses cathode luminescence. The spectroscopic element transmits only cathode luminescence of a specific wavelength by reflecting the cathode luminescence multiple times by mirrors arranged opposite each other. With this configuration, it is possible to reduce the size of the spectrometer for dispersing the cathode luminescence compared to a case where a dispersing crystal is provided. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an outline of a cathodoluminescence spectroscopic device in a first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing an etalon element and a detector. [Diagram 3] FIG. 2 is a diagram showing multiple interference of an etalon element. [Figure 4] FIG. 4 is a diagram showing an example of display of the emission intensity of cathodoluminescence emitted from a sample in the first embodiment. [Diagram 5] FIG. 11 is a diagram showing an outline of a cathodoluminescence spectroscopic device in the second embodiment. [Figure 6] FIG. 2 is a perspective view of a sample being irradiated with an electron beam. [Figure 7] FIG. 2 is a perspective view of a detector including an etalon element and a CCD. [Figure 8] FIG. 11 is a diagram showing an example of display of the emission intensity of cathodoluminescence emitted from a sample in the second embodiment. [Figure 9] 9 is a diagram showing an example of a spectrum of a light receiving element corresponding to the region in FIG. 8. FIG. [Figure 10] 9 is a diagram showing an example of a spectrum of a light receiving element corresponding to the region in FIG. 8. FIG. [Figure 11] 9 is a diagram showing an example of a spectrum of a light receiving element corresponding to the region in FIG. 8. FIG. [Figure 12] FIG. 11 is a diagram showing an outline of a cathodoluminescence spectroscopic device in the third embodiment. [Figure 13] 13 is a diagram for explaining the incident angle of an electron beam in the third embodiment. FIG. [Figure 14] FIG. 13 is a diagram showing the configuration of a cathodoluminescence spectroscopic device in the fourth embodiment. [Figure 15] FIG. 13 is a diagram showing a spectrum when an etalon element is used. [Figure 16] FIG. 13 is a diagram showing a spectrum obtained when an analyzing crystal is used. [Figure 17] 13 is a flowchart showing an analysis process for switching from an etalon element to an analyzing crystal. [Figure 18] FIG. 13 is a diagram illustrating image overlay. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Embodiment 1] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

[0011] <Overall configuration of the cathode luminescence spectrometer> 1 is a diagram showing an outline of a cathodoluminescence spectroscopic apparatus 100 according to the first embodiment. The cathodoluminescence spectroscopic apparatus 100 according to the first embodiment is, for example, a scanning electron microscope that scans an electron beam to irradiate a sample. Note that the cathodoluminescence spectroscopic apparatus 100 is not limited to an electron microscope, and may be any apparatus capable of irradiating an electron beam to a sample.

[0012] The cathodoluminescence spectrometer 100 includes an electron gun 10, a sample stage 15, a mirror 20, a condenser lens 25, an etalon element 30, a detector 40, and a control device 50. The electron gun 10 includes an electron source 11, a condenser lens 12, a scanning coil 13, and an objective lens 14.

[0013] 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 addition, the positive direction of the Z-axis in each drawing may be referred to as the upper surface side, and the negative direction as the lower surface side.

[0014] The electron gun 10 irradiates an electron beam EB1 onto a sample Sp1 placed on a sample stage 15. 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 mirror 20 is disposed between the electron gun 10 and the sample Sp1. The electron beam EB1 passes through an opening 20a formed in the mirror 20 and then enters the sample Sp1.

[0015] The electron source 11 is an excitation source for the electron beam EB1, and emits the electron beam EB1 when a voltage is applied to it. The condenser lens 12 focuses the electron beam EB1. The scanning coil 13 scans the electron beam EB1 over the sample Sp1. The objective lens 14 narrows the electron beam EB1 to a very small diameter.

[0016] The electron gun 10 is housed in a housing connected to a vacuum exhaust mechanism so that the electron source 11 can generate the electron beam EB1. In other words, the inside of the housing is kept at a vacuum level that allows the electron source 11 to generate electrons.

[0017] When the sample Sp1 is irradiated with the electron beam EB1, electrons in the valence band of the sample Sp1 are excited to the conduction band. The resulting holes and electrons recombine to emit light. This light emission is called cathode luminescence. The cathode luminescence is emitted in all directions from the sample Sp1. The cathode luminescence includes a plurality of wavelengths. The cathode luminescence CL1 in FIG. 1 is the cathode luminescence emitted toward the mirror 20 out of the cathode luminescence emitted in all directions. In other words, the cathode luminescence CL1 is the cathode luminescence between the sample Sp1 and the mirror 20.

[0018] The mirror 20 reflects the cathode luminescence CL1 emitted from the sample Sp1. The mirror 20 reflects the cathode luminescence CL1 as cathode luminescence CL2. The cathode luminescence CL2 is collected by the collecting lens 25 onto the etalon element 30. That is, the cathode luminescence CL2 is the cathode luminescence after being reflected by the mirror 20 and before being collected onto the etalon element 30. The mirror 20 and the collecting lens 25 correspond to the "collecting mechanism" in this disclosure. The mirror 20 and the collecting lens 25, which are the collecting mechanism, may be provided integrally as a mirror lens.

[0019] The etalon element 30 is configured to be able to disperse the cathode luminescence CL2 collected by the mirror 20 and the collecting lens 25. That is, the etalon element 30 is a spectrometer that transmits only the cathode luminescence CL2 of a specific wavelength from the cathode luminescence CL2 containing a plurality of wavelengths as the cathode luminescence CL3. Hereinafter, the wavelength of the cathode luminescence CL3 may be referred to as the "wavelength after dispersion". The etalon element 30 is referred to as a Fabry-Perot interferometer. The etalon element 30 corresponds to the "dispersion element" in this disclosure.

[0020] The length of the etalon element 30 is about 5 mm to 15 mm, and the width of the etalon element 30 is about 1 mm to 5 mm. On the other hand, the size of a general dispersing crystal for dispersing cathodeluminescence is larger than the size of the etalon element. Furthermore, a cathodeluminescence spectroscopic device equipped with a dispersing crystal needs to be equipped with an optical system for dispersing light with the dispersing crystal. The length of the spectrometer that houses the optical system and the dispersing crystal is about 1500 mm to 2500 mm, and the width of the spectrometer is about 1500 mm to 2500 mm. In other words, the space required for arranging the etalon element 30 is smaller than the space required for arranging the dispersing crystal.

[0021] The detector 40 detects the intensity of the cathodoluminescence CL3 after being dispersed by the etalon element 30. The detector 40 in the first embodiment is a photomultiplier (PMT). That is, the detector 40 is a so-called photomultiplier tube. The detector 40 multiplies photoelectrons using multiple dynodes provided therein, and detects the intensity of weak light.

[0022] The control device 50 includes, as main components, a central processing unit (CPU) 51 and a memory 52. ​​The control device 50 may be configured with a dedicated hardware circuit (for example, an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA)). The memory is realized, for example, by a read only memory (ROM), a random access memory (RAM), or a hard disk drive (HDD).

[0023] The control device 50 is electrically connected to the display 60 and the input device 70. The control device 50 causes the display 60 to display, for example, information related to cathodoluminescence spectroscopy. The information related to cathodoluminescence spectroscopy includes, for example, the detection result of the detector 40, and information about an error that has occurred in the analysis device. The control device 50 receives a command input by a user using the input device 70. The input device 70 is, for example, a keyboard. The display 60 and the input device 70 may be integrally formed as a touch panel.

[0024] At least a portion of the components of the control device 50, such as the display 60 or the input device 70, may be configured separately from the cathodoluminescence spectroscopy device 100 and configured to communicate bidirectionally with the cathodoluminescence spectroscopy device 100.

[0025] The control device 50 comprehensively controls the cathodoluminescence spectrometer 100. The control device 50 receives detection values ​​from the detector 40. The control device 50 calculates the cathodoluminescence emission intensity at an arbitrary position of the sample Sp1 based on the voltage value applied to the scanning coil 13 and the detection value received from the detector 40. In this way, the control device 50 can form an image showing the distribution of the cathodoluminescence emission intensity 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 spectral analysis to an arbitrary wavelength.

[0026] <Configuration of etalon element> 2 and 3, a specific example of splitting in the etalon element 30 and changing the wavelength after splitting to an arbitrary wavelength will be described below. Fig. 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 between them. The distance d is called an air gap.

[0027] The half mirror 31 reflects a portion of the cathodoluminescence CL2 reflected by the mirror 20 and transmits the other portion. The half mirror 32 reflects a portion of the cathodoluminescence CL2 that has transmitted through the half mirror 31 and transmits the other portion. The detector 40 detects the cathodoluminescence CL3 that has transmitted through the half mirror 32.

[0028] 2, the etalon element 30 includes a 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.

[0029] The driving device 33 in the first embodiment is formed to include a piezoelectric element. The piezoelectric element is an element that is driven by utilizing the piezoelectric effect. When a voltage is applied to the piezoelectric element included in the driving device 33, the half mirror 31 and the half mirror 32 are pressed, and the distance d changes. That is, the control device 50 can change the distance d by adjusting the voltage value applied to the piezoelectric element included in the driving device 33.

[0030] This allows the control device 50 to adjust the wavelength of the cathode luminescence CL3 passing through the etalon element 30. The driving device 33 may change the distance d without using a piezoelectric element. For example, the driving device 33 may be configured to include a motor or an electromagnetic actuator.

[0031] Fig. 3 is a diagram showing multiple interference of the etalon element 30. As shown in Fig. 3, the cathode luminescence CL2 reflected by the mirror 20 is incident on the half mirror 31. A part of the cathode luminescence CL2 is transmitted through the half mirror 31. In Fig. 3, the cathode luminescence CL2 that has transmitted through the half mirror 31 is shown as cathode luminescence CLg.

[0032] The cathode luminescence CLg is repeatedly reflected between the half mirror 31 and the half mirror 32. The half mirror 31 and the half mirror 32 cause the cathode luminescence CLg, whose distance d is an integer multiple of the wavelength, to be reflected multiple times, thereby generating interference. The cathode luminescence CLg of a specific wavelength is constructively generated due to the occurrence of interference. As a result, the etalon element 30 allows only the cathode luminescence CL3 of the specific wavelength to be transmitted through the half mirror 32.

[0033] 4 is a diagram showing a display example of the emission intensity of cathode luminescence emitted from the sample Sp1 in the embodiment 1. As described above, the control device 50 calculates the emission intensity of cathode luminescence at a position on the sample Sp1 where the electron beam EB1 is irradiated. The control device 50 scans the electron beam EB1 over the entire sample Sp1 to form an image showing the distribution of the emission intensity of cathode luminescence over the entire sample Sp1.

[0034] 4 shows an example in which an image Im1 formed by the control device 50 is displayed on the display 60. As shown in Fig. 4, the display 60 displays a sample Sp1 viewed in plan from the positive side of the Z axis.

[0035] In the cathodoluminescence spectrometer 100 according to the first embodiment, the electron beam EB1 is scanned by changing the magnetic field through adjustment of the voltage value applied to the scanning coil 13. As a result, the electron beam EB1 is incident on the entire sample Sp1 when viewed in plan from the positive side of the Z axis.

[0036] The control device 50 forms an image Im1 using the position where the electron beam EB1 is incident and the emission intensity of cathode luminescence at that position. In FIG. 4, the image Im1 shows an area Ar1 indicated by a solid line and an area Ar2 indicated by a dashed line. The area Ar1 is an area where the emission intensity of cathode luminescence is higher than that of the area Ar2. In addition, the areas of the image Im1 other than the areas Ar1 and Ar2 are areas that were not scanned or areas where the emission of cathode luminescence was not detected. The control device 50 may display the image Im1 showing the emission intensity of cathode luminescence superimposed on an image of the sample Sp1 obtained by detecting secondary electrons.

[0037] In this way, the cathodoluminescence spectroscopic apparatus 100 in the first embodiment can visually display the emission intensity of cathodoluminescence generated when the sample Sp1 is irradiated with the electron beam EB1 using the etalon element 30. As described above, the space required for arranging the etalon element 30 is smaller than the space required for arranging the dispersing crystal.

[0038] Thereby, in the cathode luminescence spectroscopic apparatus 100 of the first embodiment, it is possible to miniaturize the spectrometer for dispersing cathode luminescence. As a result, it is possible to miniaturize the cathode luminescence spectroscopic apparatus 100 or to arrange other devices inside the cathode luminescence spectroscopic apparatus 100. In addition, since the cost of the etalon element 30 is cheaper than the cost of the dispersing crystal, it is possible to reduce the cost of the entire cathode luminescence spectroscopic apparatus 100.

[0039] When using a dispersive crystal for spectroscopy, the wavelength of the cathodoluminescence dispersed by the dispersive crystal changes depending on the angle at which the cathodoluminescence is incident on the dispersive crystal. Therefore, in order to obtain a spectrum for each wavelength, it is necessary to change the angle of the dispersive crystal every time detection is performed. In order to accurately change the angle of the dispersive crystal, appropriate zero point correction is required, so the total time required for spectroscopy can be long.

[0040] On the other hand, in the cathodoluminescence spectroscopic apparatus 100 in the first embodiment, the wavelength after dispersion can be easily changed by simply adjusting the voltage applied to the piezoelectric element included in the driving device 33. That is, in the cathodoluminescence spectroscopic apparatus 100 in the first embodiment, the time required for analyzing cathodoluminescence can be reduced compared to the case where a dispersing crystal is used. [Embodiment 2] In the cathodoluminescence spectrometer 100 of the first embodiment, a configuration has been described in which the emission intensity of cathodoluminescence over the entire surface of the sample Sp1 is detected by scanning the electron beam EB1. In the second embodiment, a configuration will be described in which an image showing the emission intensity of cathodoluminescence is formed without scanning the electron beam EB1. Note that the description of the configuration of the cathodoluminescence spectrometer 100A of the second embodiment that overlaps with the cathodoluminescence spectrometer 100 of the first embodiment will not be repeated.

[0041] FIG. 5 is a diagram showing an outline of a cathodoluminescence spectroscopic apparatus 100A in the second embodiment. The same sample Sp1 as in the first embodiment is placed on the sample stage 15 in the second embodiment. As shown in FIG. 5, in the cathodoluminescence spectroscopic apparatus 100A in the second embodiment, a detector 40A that detects cathodoluminescence CL3 is realized as a CCD (Charge Coupled Device). The detector 40A, which is a CCD, has a plurality of light receiving elements. The detector 40A and the etalon element 30 may be provided as one body.

[0042] In the second embodiment, the electron beam EB2 emitted from the electron source 11 is incident on the sample Sp1 with a width Wd without being narrowed down to a minute diameter by the objective lens 14. As a result, the electron beam EB2 is irradiated onto a certain area on the surface of the sample Sp1 on the positive side of the Z axis. Hereinafter, the area irradiated with the electron beam EB2 is referred to as the "irradiation area." The area of ​​the irradiation area can be controlled by the electron gun optical system to a size according to the optical focusing system. The irradiation area has an area of, for example, about 0.16 square millimeters.

[0043] Fig. 6 is a perspective view of a sample Sp1 being irradiated with an electron beam EB2. In Fig. 6, the electron beam EB2 is irradiated onto an irradiation area Fc1 on the surface of the sample Sp1. The irradiation area Fc1 has a circular shape with a diameter of width Wd. A point Cp indicates the center of the circular irradiation area Fc1.

[0044] 6, the irradiation area Fc1 includes an area Fa1, an area Fa2, and an area Fa3. When the electron beam EB2 is irradiated, cathode luminescence CL11, CL12, and CL13 are emitted from the areas Fa1, Fa2, and Fa3, respectively. The cathode luminescence CL11, CL12, and CL13 are reflected by the mirror 20 as cathode luminescence CL21, CL22, and CL23, and are collected on the etalon element 30.

[0045] Fig. 7 is a perspective view of the etalon element 30 and a detector 40A which is a CCD. As shown in Fig. 7, cathode luminescence light CL21, CL22, and CL23 enters a half mirror 31 of the etalon element 30. Cathodoluminescence light CL31, CL32, and CL33 of specific wavelengths are transmitted through the half mirror 32 due to multiple interference. The detector 40A which is a CCD has a plurality of light receiving elements including light receiving elements LE1, LE2, and LE3.

[0046] Cathodoluminescence CL31 is detected by light receiving element LE1. Cathodoluminescence CL32 is detected by light receiving element LE2. Cathodoluminescence CL33 is detected by light receiving element LE3. The detection value of light receiving element LE1 indicates the cathode luminescence emission intensity of region Fa1. The detection value of light receiving element LE2 indicates the cathode luminescence emission intensity of region Fa2. The detection value of light receiving element LE3 indicates the cathode luminescence emission intensity of region Fa3. In this way, in the cathode luminescence spectroscopic apparatus 100A of embodiment 2, an image indicating the cathode luminescence emission intensity over the entire sample Sp1 can be formed without scanning the electron gun 10.

[0047] 8 is a diagram showing a display example of the emission intensity of the cathode luminescence emitted from the sample Sp1 in the second embodiment. The display 60 displays an image Im2. The image Im2 is an image formed by the control device 50 using the detection result of the detector 40A, which is a CCD. In the image Im2, an area Fd1 corresponds to the irradiation area Fc1 in FIG. 6. Moreover, in the image Im2, areas Fb1, Fb2, and Fb3 correspond to areas Fa1, Fa2, and Fa3 in FIG. 6, respectively.

[0048] Area Ar1 in FIG. 8 corresponds to area Ar1 in FIG. 4. Area Ar2 in FIG. 8 corresponds to area Ar2 in FIG. 4. That is, area Ar1 is the area with the highest luminescence intensity, and area Ar2 is the area with a lower luminescence intensity than area Ar1. Furthermore, area Ar3 of area Fd1, which is not area Ar1 or area Ar2, is the area where cathode luminescence emission was not detected. This allows the user to understand by looking at image Im2 that the cathode luminescence emission intensity increases in the order of light receiving elements LE1, LE2, and LE3.

[0049] In this way, in the second embodiment, by using the etalon element 30 for spectral analysis, the spectrometer for spectrally analyzing the cathode luminescence in the cathode luminescence spectrometer 100A can be miniaturized and the cost can be reduced. As described above, the etalon element 30 scans the wavelength of light using the driving device 33 including the piezoelectric element. Therefore, the analysis time when the etalon element 30 is used is shorter than the analysis time when a spectrometer that needs to change the position of the dispersing crystal is used. That is, the analysis time can be shortened in the second embodiment as well. Furthermore, in the cathode luminescence spectrometer 100A of the second embodiment, the image Im2 is formed using a CCD having a plurality of light receiving elements and the etalon element 30 that can simultaneously spectrally analyze a plurality of cathode luminescence. As a result, the control device 50 can form the image Im2 showing the emission intensity of the cathode luminescence emitted from the sample Sp1 without scanning the electron gun 10, and the time required for image formation can be reduced. Furthermore, by integrally forming the detector 40A, which is a CCD, and the etalon element 30, the cathodoluminescence spectroscopic apparatus 100A can be made even more compact.

[0050] Furthermore, since there is no need to scan the electron beam EB2, it is possible to simultaneously perform energy dispersive X-ray spectroscopy or wavelength dispersive X-ray spectroscopy and cathodoluminescence analysis. It is also possible to detect a spectrum for each light receiving element included in the detector 40A, which is a CCD. That is, the cathodoluminescence spectroscopic device 100A in the second embodiment can distinguish and display the regions Ar1 to Ar3 according to not only the emission intensity but also the wavelength.

[0051] In the following, an example of displaying the regions Ar1 to Ar3 in a distinguished manner according to wavelength will be described with reference to Figs. 9 to 11. The control device 50 causes the detector 40A to detect the cathode luminescence CL3 while changing the distance d between the half mirror 31 and the half mirror 32 of the etalon element 30. As a result, each light receiving element of the detector 40A detects the emission intensity of the cathode luminescence CL3 of a plurality of wavelengths. The plurality of wavelengths may be, for example, wavelengths between 200 nm and 1300 nm. Fig. 9 is a diagram showing an example of the spectrum of the light receiving element LE3 corresponding to the region Ar1 of Fig. 8. As shown in Fig. 9, the light receiving element LE3 detects the cathode luminescence CL3 with an emission intensity exceeding the threshold value Th at a wavelength near 400 nm.

[0052] Next, Fig. 10 is a diagram showing an example of the spectrum of the light receiving element LE2 corresponding to the region Ar2 in Fig. 8. As shown in Fig. 10, in the light receiving element LE2, cathodoluminescence CL3 having an emission intensity exceeding the threshold value Th at a wavelength near 1000 nm is detected. Furthermore, Fig. 11 is a diagram showing an example of the spectrum of the light receiving element LE1 corresponding to the region Ar3 in Fig. 8. As shown in Fig. 11, in the light receiving element LE1, cathodoluminescence CL3 having an emission intensity exceeding the threshold value Th is not detected between wavelengths of 200 nm and 1300 nm. The threshold value Th can be determined in advance depending on the sensitivity of the detector 40A, which is a CCD, and the like.

[0053] In this way, the cathodoluminescence spectroscopic device 100A of the second embodiment can detect the spectrum of cathodoluminescence CL3 for each light receiving element of the detector 40A. Therefore, in the cathodoluminescence spectroscopic device 100A of the second embodiment, when displaying the image Im2, the areas Ar1 to Ar3 corresponding to each light receiving element can be displayed differently according to not only the emission intensity but also the wavelength. Specifically, the control device 50 displays the image Im2 on the display 60 shown in FIG. 8 with a color corresponding to the detected wavelength.

[0054] For example, the control device 50 displays the area corresponding to the light receiving element LE3 that detected a high emission intensity at a wavelength near 400 nm in blue, and displays the area 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 may change the shade of the displayed color according to the emission intensity in order to distinguish between light receiving elements that detected cathodoluminescence exceeding the threshold Th at the same wavelength. In this way, by changing the display method of the area corresponding to the light receiving element according to the emission intensity and wavelength, the cathodoluminescence spectroscopic device 100A in the second embodiment allows the user to easily grasp the difference in emission intensity and wavelength for each position on the sample Sp1.

[0055] [Embodiment 3] In the cathodoluminescence spectroscopic apparatus 100A of the second embodiment, a configuration has been described in which the emission intensity of cathodoluminescence is detected using a detector 40A including a plurality of light receiving elements without scanning the electron beam EB2. In the third embodiment, a configuration in which the arrangement of the electron gun 10 is changed will be described. Note that, in the cathodoluminescence spectroscopic apparatus 100B of the third embodiment, the description of the configuration that overlaps with that of the cathodoluminescence spectroscopic apparatus 100A of the second embodiment will not be repeated.

[0056] Fig. 12 is a diagram showing an outline of a cathodoluminescence spectrometer 100B in the third embodiment. As shown in Fig. 12, the electron gun 10 is disposed at a position spaced apart from the sample Sp1 in the X-axis direction. In the second embodiment, the electron beam EB2 is incident on the sample Sp1 at an incident angle of 0 degrees, but in the third embodiment, the electron beam EB is incident on the sample Sp1 at an incident angle greater than 0 degrees. In Fig. 12, a condenser lens 25 is disposed between the mirror 20 and the sample Sp1.

[0057] 13 is a diagram for explaining the angle of incidence of the electron beam EB2 in the third embodiment. In the second and third embodiments, 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. As shown in FIG. 6, the electron beam EB2 in the second embodiment is incident on the irradiation area Fc1. In the second embodiment, the electron beam EB2 passing through the point Cp of the irradiation area Fc1 is incident perpendicularly from the normal direction of the sample stage 15. That is, the angle of incidence is 0 degrees.

[0058] 13, the electron beam EB2 irradiated to the point Cp which is the center of the irradiation region Fc1 is incident on the sample Sp1 at an incident angle θ, which is greater than 0 degrees and smaller than 90 degrees.

[0059] In this manner, also in the third embodiment, by using the etalon element 30 for spectral analysis, the spectrometer for spectrally analyzing the cathode luminescence in the cathodoluminescence spectroscopic device 100B can be made smaller, the cost can be reduced, and the analysis time can be shortened. Furthermore, when the electron beam EB2 is not scanned, the electron beam EB2 does not need to be irradiated perpendicularly to the sample stage 15. Therefore, in the third embodiment, the electron gun 10 irradiates the sample Sp1 so that the angle at which the electron beam EB2 is incident on the sample Sp1 is greater than 0 degrees and less than 90 degrees. This improves the degree of freedom in the arrangement of the electron gun 10. Furthermore, the mirror 20 does not need to have an opening 20a formed therein. [Embodiment 4] In the cathode luminescence spectroscopic apparatuses 100, 100A, and 100B of the first to third embodiments, a configuration has been described in which the cathode luminescence emission intensity is detected using the etalon element 30. In the fourth embodiment, a configuration will be described in which a spectroscope is further provided in addition to the etalon element 30. Note that in the cathode luminescence spectroscopic apparatus 100C of the fourth embodiment, the description of the configuration that overlaps with that of the cathode luminescence spectroscopic apparatus 100 of the first embodiment will not be repeated.

[0060] Fig. 14 is a diagram showing the configuration of a cathodoluminescence spectroscopic apparatus 100C in the embodiment 4. Fig. 14(A) shows an example of spectroscopic analysis using an etalon element 30, and Fig. 14(B) shows an example of spectroscopic analysis using an analyzing crystal 35.

[0061] 14(A), the cathodoluminescence spectroscopic device 100C further includes, as a spectrometer, a dispersing crystal 35 in addition to the etalon element 30. The dispersing crystal 35 is configured to be able to reflect cathodoluminescence CL3 of a specific wavelength out of the cathodoluminescence CL2 collected by the mirror 20.

[0062] 14(A), the cathodoluminescence spectroscopic apparatus 100C further includes a switching mechanism 80. The switching mechanism 80 is configured to be able to switch the focusing destination of the mirror 20 between the etalon element 30 and the dispersing crystal 35. The switching mechanism 80 may be, for example, a motor that switches the positions of the etalon element 30 and the dispersing crystal 35, or a motor that changes 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 focusing destination of the mirror 20.

[0063] 14(A) shows a state in which the mirror 20 focuses light on the etalon element 30. The detector 40 detects the emission intensity of the cathodoluminescence CL3 dispersed 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 dispersed using the etalon element 30 corresponds to the "first image" of the present disclosure.

[0064] 14(B) shows a state after the focusing target of the mirror 20 has been switched from the etalon element 30 to the dispersing crystal 35. The detector 40 detects the intensity of the cathodoluminescence CL3 dispersed by the dispersing 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 dispersed using the dispersing crystal 35 corresponds to the "second image" of the present disclosure. The control device 50 can also switch the focusing target of the mirror 20 from the dispersing crystal 35 to the etalon element 30.

[0065] <About wavelength resolution> Fig. 15 is a diagram showing a spectrum when the etalon element 30 is used. Fig. 16 is a diagram showing a spectrum when the dispersing crystal 35 is used. Figs. 15 and 16 show the results of cathodoluminescence analysis of the same sample.

[0066] 15 and 16, the shapes of the waveforms showing the spectrum shown as region Ar3 are different. Specifically, when the etalon element 30 is used, high intensity is shown in a wide wavelength range in region Rg1. On the other hand, when the dispersing crystal 35 is used, high intensity is shown in a narrower wavelength range in region Rg2 than when the etalon element 30 is used. That is, the wavelength resolution of the dispersing crystal 35 is higher than that of the etalon element 30.

[0067] In short, analysis using the etalon element 30 can be performed in a shorter time than analysis using the dispersive crystal 35, but since the etalon element 30 has a lower wavelength resolution than the dispersive crystal 35, accurate detection results may not be obtained.

[0068] Therefore, in the fourth embodiment, the control device 50 performs analysis using the etalon element 30, and then performs analysis using the dispersing crystal 35. FIG. 17 is a flowchart showing an analysis process for switching from the etalon element 30 to the dispersing crystal 35. As shown in FIG. 14(A), the control device 50 performs spectrum analysis using the etalon element 30 (step S1). As described above, when the etalon element 30 is used, the cathodoluminescence spectroscopic device 100C can perform analysis in a short time.

[0069] The control device 50 forms an image based on the cathodoluminescence CL3 dispersed 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 has checked the image displayed on the display 60 wishes to detect the emission intensity of the cathodoluminescence more accurately. When the user wishes to detect the emission intensity more accurately, the cathodoluminescence spectroscopic device 100C of the fourth embodiment can receive a command from the input device 70 to switch to the dispersing crystal 35 for detection.

[0070] The cathodoluminescence spectroscopic device 100C may receive an instruction to change the area to be irradiated or scanned with the electron beam EB1, in addition to the instruction to switch to the dispersing crystal 35 for detection. That is, when it is desired to detect only a part of the image displayed in step S2 by the dispersing crystal 35, the user can select the detection area from the surface of the sample Sp1.

[0071] The control device 50 determines whether or not a command to switch to the dispersing crystal 35 has been received from the user (step S3). If the control device 50 determines that a command to switch has not been received (NO in step S3), it determines whether or not a command to end the analysis process has been received (step S4). If the control device 50 determines that a command to end the analysis process has been received (YES in step S4), it ends the analysis process. If the control device 50 determines that a command to end the analysis process has not been received (NO in step S4), it repeats the process of step S3.

[0072] When the control device 50 determines that it has received a command to switch (YES in step S3), it switches the focusing destination of the mirror 20 to the dispersing crystal 35 (step S5). That is, the control device 50 controls the switching mechanism 80. At this time, if a detection area is received, the control device 50 controls the angle of the electron beam EB1 by the scanning coil 13 and the aperture by the objective lens 14 to change the area where the electron beam EB1 is incident on the sample Sp1.

[0073] 14(B), the control device 50 performs spectral analysis using the dispersive crystal 35 (step S6). When the dispersive crystal 35 is used, spectral analysis with high wavelength resolution can be performed. The control device 50 forms an image based on the cathodoluminescence CL3 dispersed using the dispersive crystal 35, and displays the image on the display 60 (step S7).

[0074] In this way, also in the fourth embodiment, the analysis time can be shortened in the cathodoluminescence spectroscopic device 100A by using the etalon element 30 for spectroscopic analysis. Furthermore, in the fourth embodiment, the dispersing crystal 35 is further provided, and the focusing destination of the mirror 20 can be switched depending on the application. That is, in the fourth embodiment, after performing analysis using the etalon element 30 that can perform analysis in a short time, the dispersing crystal 35 with high wavelength resolution can be used to perform analysis on locations that require more accurate analysis, thereby enabling efficient analysis.

[0075] [Variations] (1) In the first embodiment, an example has been described in which the etalon element 30 is provided with a driving device. However, the cathodoluminescence spectroscopic apparatus 100 may be configured to 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 include a plurality of etalon elements 30 with different distances d, and the switching mechanism 80 may switch the focus of light between the plurality of etalon elements 30.

[0076] (2) In the second embodiment, an example has been described in which the image Im2 is displayed based on the emission intensity or wavelength of the cathodoluminescence CL3 detected by the detector 40A, which is a CCD. In the modified example, a configuration will be described in which the control device 50 causes the display 60 to display another image by superimposing the image Im2.

[0077] 18 is a diagram for explaining image superimposition. As described in the first embodiment, the control device 50 may superimpose an image of the sample Sp1 obtained by detecting secondary electrons on the image Im1 and display it. Similarly, in the second embodiment, the control device 50 may superimpose an image obtained by detecting secondary electrons on the image Im2 and display it.

[0078] In the second embodiment, a CCD is used as the detector 40A. The CCD can detect not only the reflection of cathodoluminescence but also the reflected light from the sample Sp1 when general visible light is used as illumination. The control device 50 in the second embodiment may display an image of the sample Sp1 obtained by detecting the reflected light when general visible light is used as illumination, superimposed on the image Im2.

[0079] The image Im3 shown in Fig. 18(A) is an image obtained by detecting secondary electrons or an image obtained by detecting reflected light when general visible light is used as illumination. That is, the image Im3 shown in Fig. 18(A) is acquired without using cathodoluminescence.

[0080] Next, Fig. 18(B) displays an image Im4 when the detector 40A, which is a CCD, detects the cathode luminescence CL2 before it is dispersed by the etalon element 30. In other words, the image Im4 in Fig. 18(B) is acquired by the detector 40A detecting the cathode luminescence CL2 in a state in which the etalon element 30 is removed in Fig. 5. The image Im4 shows an area Ar4 in which the detector 40A detects the emission of the cathode luminescence CL2.

[0081] The cathode luminescence CL2 before being dispersed by the etalon element 30 contains cathode luminescence of more wavelengths than the cathode luminescence CL3 after being dispersed by the etalon element 30. For example, in Fig. 9, the spectrum when the cathode luminescence CL3 is dispersed at intervals of 200 nm to 1300 nm using the etalon element 30 is described, but the cathode luminescence CL2 may also contain cathode luminescence of wavelengths other than 200 nm to 1300 nm. Therefore, the region Ar4 is a region that includes the regions Ar1 and Ar2.

[0082] The control device 50 can superimpose the image Im3 and the image Im4 on the image Im2 of FIG. 8. The image Im5 in FIG. 18(C) is an image obtained by superimposing the image Im3 of FIG. 18(A) and the image Im4 of FIG. 18(B) on the image Im2 of FIG. 8. In this manner, in FIG. 18(C), the image Im3 acquired without using cathodoluminescence and the image Im2 obtained by detecting the cathodoluminescence CL3 are superimposed. This allows the cathodoluminescence spectroscopic device 100A to easily grasp at which part of the sample Sp1 the cathodoluminescence CL3 after dispersion is emitted, using the image of the sample Sp1 obtained from the reflection of secondary electrons or visible light.

[0083] 18(C), an image Im4 obtained by detecting the cathode luminescence CL2 before spectroscopic analysis and an image Im2 obtained by detecting the cathode luminescence CL3 after spectroscopic analysis are superimposed on each other, which allows the user to easily grasp the difference in luminescence intensity between the cathode luminescence CL2 before spectroscopic analysis and the cathode luminescence CL3 after spectroscopic analysis.

[0084] For example, if the emission intensity of the cathode luminescence CL3 after the splitting is low and only the cathode luminescence CL3 after the splitting is displayed on the display 60, the user may recognize that the cathode luminescence itself is not emitting light. However, in the cathode luminescence spectroscopic device 100A in the modified example, the image Im4 and the image Im2 are superimposed on each other, so that the area Ar4 where the cathode luminescence CL2 before the splitting is emitting light is displayed on the display 60, and it is possible to prevent the user from overlooking the emission of light from the cathode luminescence itself. Note that the image Im5 may be an image in which only the image Im2 and the image Im3 are superimposed, or an image in which only the image Im2 and the image Im4 are superimposed.

[0085] (3) In the fourth embodiment, a configuration has been described in which the switching mechanism 80 switches the focusing destination of the mirror 20 between the dispersing crystal 35 and the etalon element 30. However, the cathodoluminescence reflected by the mirror 20 may be focused simultaneously on the dispersing crystal 35 and the etalon element 30. For example, a half mirror may be further provided at the focusing destination of the mirror 20, and the cathodoluminescence from the mirror 20 may be split by the half mirror to be focused simultaneously on the dispersing crystal 35 and the etalon element 30.

[0086] [Aspects] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0087] (Item 1) A cathodoluminescence spectrometer according to one embodiment includes an electron gun for irradiating an electron beam onto a sample, a focusing mechanism for focusing cathodoluminescence emitted from the sample by the irradiation of the electron beam onto the sample, a spectroscopic element configured to be able to disperse the cathodoluminescence focused by the focusing mechanism, a detector for detecting the intensity of the cathodoluminescence dispersed by the spectroscopic element, and a control device for receiving the detection result from the detector and controlling the cathodoluminescence spectrometer. The spectroscopic element includes a first mirror and a second mirror disposed at a position facing the first mirror. The first mirror reflects a part of the cathodoluminescence focused by the focusing mechanism and transmits a part of it. The second mirror reflects a part of the cathodoluminescence that has transmitted through the first mirror and transmits a part of it. The first mirror and the second mirror cause interference between the cathodoluminescence between the first mirror and the second mirror, and transmit cathodoluminescence of a specific wavelength from the second mirror. The detector detects the intensity of the cathodoluminescence transmitted through the second mirror.

[0088] According to the analysis device described in paragraph 1, by using the etalon element 30 for spectral analysis, the analysis time can be shortened in the cathodoluminescence spectroscopic device 100A.

[0089] (Clause 2) 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 disperses first cathodoluminescence emitted from a first area of ​​the irradiation area, and disperses second cathodoluminescence emitted from a second area of ​​the irradiation area different from the first area. The first light receiving element receives the first cathodoluminescence dispersed by the spectroscopic element. The second light receiving element receives the second cathodoluminescence dispersed by the spectroscopic element.

[0090] According to the analyzing device described in the second aspect, it is possible to form an image showing the emission intensity of cathodoluminescence in the entire sample Sp1 without scanning the electron gun 10.

[0091] (Clause 3) The angle of incidence of the electron beam on the sample is greater than 0 degrees and less than 90 degrees.

[0092] According to the analyzing apparatus described in the third aspect, the degree of freedom in arranging the electron gun 10 is improved.

[0093] (Item 4) The light separating element further includes a drive device that changes the distance between the first mirror and the second mirror.

[0094] According to the analysis device described in item 4, it is possible to disperse light into a plurality of wavelengths using a single dispersing element.

[0095] (Item 5) The driving device is formed to include a piezoelectric element.

[0096] According to the analyzing device described in the fifth aspect, the distance between the first mirror and the second mirror can be changed accurately and in a short time by the piezoelectric element.

[0097] (Item 6) The optical fiber further includes a dispersing crystal configured to be capable of reflecting cathode luminescence of a specific wavelength among the cathode luminescence collected by the collecting mechanism, and a switching mechanism for switching the collecting destination of the collecting mechanism between the dispersing crystal and the dispersing element.

[0098] According to the analytical device described in paragraph 6, the spectrometer can be easily switched depending on the application.

[0099] (Clause 7) The control device forms a first image based on the cathodoluminescence dispersed by the dispersing element, and when a command to switch to the dispersing crystal is received, displays a second image based on the cathodoluminescence dispersed by the dispersing crystal.

[0100] According to the analyzing device described in the seventh aspect, after dispersing light with a dispersing element having a short analysis time, dispersing light with a dispersing crystal having a high wavelength resolution can be performed.

[0101] With regard to the above-mentioned embodiments and modified examples, it has been intended from the outset of the application that the configurations described in the embodiments may be appropriately combined, including combinations not mentioned in the specification, to the extent that no inconvenience or contradiction arises.

[0102] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0103] 10 electron gun, 11 electron source, 12 condenser lens, 13 scanning coil, 14 objective lens, 15 sample stage, 20 mirror, 20a aperture, 30 etalon element, 31, 32 half mirror, 33 drive device, 35 analyzing crystal, 40, 40A detector, 50 control device, 52 memory, 60 display, 70 input device, 80 switching mechanism, 100, 100A, 100B, 100C cathodoluminescence spectrometer, Ar1 to Ar4, Fa1 to Fa3, Fb1 to Fb3, Fd1, Rg1, Rg2 area, CL1 to CL3, CL11 to CL13, CL21 to CL23, CL31 to CL33, CLg cathodoluminescence, Cp point, EB1, EB2 electron beam, Fc1 irradiation area, Im1 to Im5 Image, LE1 to LE3 photodetectors, Sp1 sample, Wd width, d distance, Th threshold.

Claims

1. A cathodoluminescence spectroscopic device, comprising: an electron gun for irradiating an electron beam onto a sample; a focusing mechanism for focusing cathodoluminescence emitted from the sample by irradiating the sample with the electron beam; a spectroscopic element configured to be able to disperse the cathodoluminescence collected by the light collecting mechanism; a detector that detects the intensity of the cathodoluminescence dispersed by the spectroscopic element; A control device that receives a detection result from the detector and controls the cathodoluminescence spectrometer; an analyzing crystal configured to be capable of reflecting cathode luminescence of a specific wavelength among the cathode luminescence collected by the light collecting mechanism; a switching mechanism for switching a focusing target of the focusing mechanism to the dispersing crystal or the dispersing element, The spectroscopic element is a first mirror and a second mirror provided at a position opposite to the first mirror, the first mirror reflects a portion of the cathode luminescence collected by the light collecting mechanism and transmits a portion of the cathode luminescence; the second mirror reflects a portion of the cathodoluminescence transmitted through the first mirror and transmits a portion of the cathodoluminescence, The first mirror and the second mirror cause cathodoluminescence between the first mirror and the second mirror to interfere with each other, and transmit cathodoluminescence of a specific wavelength from the second mirror; The detector detects the intensity of the cathode luminescence transmitted through the second mirror.

2. the detector includes a first light receiving element and a second light receiving element; the electron gun irradiates an irradiation region on a surface of the sample with an electron beam; The spectroscopic element is A first cathodoluminescence emitted from a first region of the irradiated region is dispersed; A second cathode luminescence emitted from a second region of the irradiation region different from the first region is dispersed; The first light receiving element receives the first cathodoluminescence separated by the spectroscopic element, The cathodoluminescence spectroscopic apparatus according to claim 1 , wherein the second light receiving element receives the second cathodoluminescence separated by the spectroscopic element.

3. 3. The cathodoluminescence spectroscopic apparatus according to claim 2, wherein the incident angle of the electron beam when it is incident on the sample is greater than 0 degrees and smaller than 90 degrees.

4. 4. The cathodoluminescence spectroscopic apparatus according to claim 1, wherein the spectroscopic element further comprises a drive device that changes a distance between the first mirror and the second mirror.

5. The cathodoluminescence spectroscopic apparatus according to claim 4 , wherein the driving device is formed to include a piezoelectric element.

6. The control device includes: forming a first image based on the cathodoluminescence dispersed by the spectroscopic element; The cathodoluminescence spectroscopic device according to claim 1 , wherein when a command to switch to the spectroscopic crystal is received, a second image is displayed based on the cathodoluminescence dispersed by the spectroscopic crystal.

Images