CN115938897A

CN115938897A - Cathodoluminescence light-splitting device

Info

Publication number: CN115938897A
Application number: CN202210942314.8A
Authority: CN
Inventors: 三田村茂宏
Original assignee: Shimadzu Corp
Current assignee: Shimadzu Corp
Priority date: 2021-08-24
Filing date: 2022-08-08
Publication date: 2023-04-07
Also published as: JP2023031001A

Abstract

The invention provides a cathodoluminescence spectroscopy device. A cathodoluminescence spectroscopy device (100) is provided with an electron gun (10), a mirror (20), an etalon element (30), a detector (40), and a control device (50). The etalon element (30) includes a first half mirror and a second half mirror. The second half mirror is disposed at a position opposite to the first half mirror. The first half mirror reflects a part of the cathodoluminescence (CL 2) condensed by the reflecting mirror (20) and transmits a part of the cathodoluminescence. The second half mirror reflects a part of the cathode luminescence transmitted through the first half mirror and transmits a part of the cathode luminescence. The first half mirror and the second half mirror cause the cathodoluminescence between the first half mirror and the second half mirror to interfere, so that cathodoluminescence (CL 3) of a specific wavelength is transmitted through the second half mirror. The detector (40) detects the intensity of the cathodoluminescence (CL 3) transmitted through the second half mirror.

Description

Cathodoluminescence spectrometer

Technical Field

The present disclosure relates to a cathodoluminescence spectroscopy apparatus.

Background

Conventionally, a technique for obtaining information such as a lattice defect or a distribution of impurities of a sample by detecting cathodoluminescence emitted from the sample is known.

For example, japanese patent application laid-open No. 2000-206046 discloses the following cathodoluminescence spectroscopy apparatus: the sample is irradiated with an electron beam to generate cathodoluminescence, and the cathodoluminescence is dispersed using a spectroscopic crystal.

Disclosure of Invention

In the cathodoluminescence spectrometer of jp 2000-206046 a, a spectroscopic crystal is used as a spectrometer, and therefore, the spectroscopic crystal itself needs to be disposed inside the cathodoluminescence spectrometer. Therefore, the cathodoluminescence spectrometer needs to have a space for disposing the spectroscopic crystal, and the size of the spectrometer may be increased. As a result, the cathodoluminescence spectrometer itself may be increased in size.

The present invention has been made to solve the above-described problems, and an object of the present invention is to reduce the size of a spectrometer for splitting cathodoluminescence in a cathodoluminescence splitting apparatus.

The cathodoluminescence spectrometer of the present disclosure includes an electron gun, a light collecting mechanism, a spectroscopic element, a detector, and a control device. The electron gun irradiates the sample with an electron beam. The light-condensing means condenses cathode emission emitted from the sample by irradiating the sample with an electron beam. The light-splitting element is configured to be able to split the cathodoluminescence condensed by the condensing means. The detector detects the intensity of the cathodoluminescence that has been split by the splitting element. The control device receives the detection result from the detector to control the cathodoluminescence light-splitting device. The light splitting element includes a first half mirror and a second half mirror. The second half mirror is disposed at a position opposite to the first half mirror. The first half mirror reflects a part of the cathode emission light condensed by the condensing means and transmits a part of the cathode emission light condensed by the condensing means. The second half mirror reflects a part of the cathode emission transmitted through the first half mirror and transmits a part of the cathode emission transmitted through the first half mirror. The first half mirror and the second half mirror cause cathode luminescence between the first half mirror and the second half mirror to interfere, so that cathode luminescence of a specific wavelength is transmitted through the second half mirror. The detector detects the intensity of the cathodoluminescence transmitted through the second half mirror.

The above objects, features, aspects and advantages of the present invention and other objects, features, aspects and advantages will become apparent from the following detailed description, which is to be read in connection with the accompanying drawings.

Drawings

Fig. 1 is a diagram showing an outline of a cathodoluminescence spectroscopy apparatus according to embodiment 1.

Fig. 2 is a schematic diagram showing an etalon element and a detector.

Fig. 3 is a diagram showing multiple interference of etalon elements.

Fig. 4 is a graph showing an example of the emission intensity of cathodoluminescence emitted from a sample in embodiment 1.

Fig. 5 is a diagram showing an outline of a cathodoluminescence spectroscopy apparatus according to embodiment 2.

Fig. 6 is a perspective view of a sample irradiated with an electron beam.

Fig. 7 is a perspective view of an etalon element and a detector as a CCD.

Fig. 8 is a graph showing an example of the emission intensity of cathodoluminescence emitted from a sample in embodiment 2.

Fig. 9 is a diagram showing an example of a spectrum of the light receiving element corresponding to the region of fig. 8.

Fig. 10 is a diagram showing an example of a spectrum of the light receiving element corresponding to the region of fig. 8.

Fig. 11 is a diagram showing an example of a spectrum of the light receiving element corresponding to the region of fig. 8.

Fig. 12 is a diagram showing an outline of a cathodoluminescence spectroscopy apparatus according to embodiment 3.

Fig. 13 is a diagram for explaining the incident angle of the electron beam in embodiment 3.

Fig. 14 is a diagram showing the structure of a cathodoluminescence spectroscopy apparatus according to embodiment 4.

Fig. 15 is a diagram showing a spectrum in the case where an etalon element is used.

Fig. 16 is a diagram showing a spectrum in the case where the spectroscopic crystal is used.

Fig. 17 is a flowchart showing an analysis process of switching from the etalon element to the spectroscopic crystal.

Fig. 18 is a diagram illustrating superimposition of images.

Detailed Description

[ embodiment 1]

Embodiments of the present invention will be described in detail below with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and description thereof will not be repeated.

< integral Structure of cathodoluminescence spectrometer >

Fig. 1 is a diagram showing an outline of a cathodoluminescence spectroscopy apparatus 100 according to embodiment 1. The cathodoluminescence spectrometer 100 according to embodiment 1 is, for example, a Scanning Electron Microscope (Scanning Electron Microscope) that scans and irradiates an Electron beam to a sample. The cathodoluminescence spectrometer 100 is not limited to an electron microscope, and may be any device that can irradiate a sample with an electron beam.

The cathodoluminescence spectroscopy apparatus 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.

In the following description, the normal direction of the sample stage 15 is defined as the Z-axis direction, and the surfaces perpendicular to the Z-axis direction are defined as the X-axis and the Y-axis. In the drawings, 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.

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 Z-axis direction side 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 enters the sample Sp1 after passing through the opening 20a formed in the mirror 20.

The electron source 11 is an excitation source of the electron beam EB1, and emits the electron beam EB1 by applying a voltage thereto. The condenser lens 12 condenses 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 minute diameter.

The electron gun 10 is housed in a casing to which a vacuum exhaust mechanism is connected so that the electron source 11 can generate the electron beam EB1. That is, a vacuum degree capable of generating electrons from the electron source 11 is maintained in the housing.

By irradiating the sample Sp1 with the electron beam EB1, electrons in the valence band of the sample Sp1 are excited to the conduction band. The holes thus generated are recombined with electrons, thereby generating light emission. This emission is called Cathodoluminescence (Cathodoluminescence). The cathodoluminescence was emitted from the sample Sp1 in all directions. In addition, cathodoluminescence contains multiple wavelengths. The cathode emission CL1 in fig. 1 is cathode emission emitted toward the mirror 20 among cathode emissions emitted in all directions. That is, the cathodoluminescence CL1 is cathodoluminescence from the sample Sp1 to the mirror 20.

The mirror 20 reflects the cathodoluminescence CL1 emitted from the sample Sp1. The reflecting mirror 20 reflects the cathode emission CL1 as cathode emission CL2. The cathode emission light CL2 is condensed by the condensing lens 25 to the etalon element 30. That is, the cathode luminescence CL2 is cathode luminescence after being reflected by the mirror 20 until being converged to the etalon element 30. Further, the reflecting mirror 20 and the condenser lens 25 correspond to a "light condensing mechanism" of the present disclosure. The mirror 20 and the condenser lens 25 as the condensing means may be integrally provided as a mirror lens.

The etalon element 30 is configured to be able to split the cathode emission light CL2 condensed by the reflecting mirror 20 and the condensing lens 25. That is, the etalon element 30 is a spectroscope that transmits only cathode emission CL2 of a specific wavelength among cathode emission CL2 including a plurality of wavelengths as cathode emission CL3. Hereinafter, the wavelength of the cathodoluminescence CL3 may be referred to as "wavelength after light splitting". The etalon element 30 is referred to as a fabry-perot interferometer. The etalon element 30 corresponds to a "light splitting element" of the present disclosure.

The etalon element 30 has a dimension in the longitudinal direction of about 5mm to 15mm and a dimension in the width direction of about 1mm to 5 mm. On the other hand, the size of a general spectroscopic crystal for dispersing cathodoluminescence is larger than that of the etalon element. Further, the cathodoluminescence spectrometer including the spectroscopic crystal needs to include an optical system for performing spectroscopy by the spectroscopic crystal. The size of the spectrometer housing the optical system and the spectroscopic crystal in the longitudinal direction is about 1500mm to 2500mm, and the size in the width direction is about 1500mm to 2500 mm. That is, the space required for disposing the etalon element 30 is smaller than the space required for disposing the spectroscopic crystal.

The detector 40 detects the intensity of the cathode emission CL3 dispersed 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 multiplies photoelectrons by a plurality of dynodes provided inside, and detects minute light intensity.

The control device 50 includes a CPU 51 (Central Processing Unit) and a memory 52 as main components. The control device 50 may be configured by a dedicated hardware Circuit (e.g., an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array)). The Memory is realized by, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), or an HDD (Hard Disk Drive).

The control device 50 is electrically connected to the display 60 and the input device 70. The control device 50 displays information on the cathodoluminescence spectroscopy on the display 60, for example. The information on the cathodoluminescence spectroscopy includes, for example, a detection result of the detector 40, error information generated in the analyzer, and the like. The control device 50 receives commands 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 also be integrally formed as a touch panel.

At least a part of the configuration of the control device 50, the display 60, or the input device 70 may be configured separately from the cathode emission spectrometer 100, and configured to perform bidirectional communication with the cathode emission spectrometer 100.

The control device 50 collectively controls the cathodoluminescence spectroscopy device 100. The control device 50 receives the detection value from the detector 40. The control device 50 calculates the emission intensity of 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 indicating the distribution of the emission intensity of the cathodoluminescence in the sample Sp1. The control device 50 causes the display 60 to display the formed image. The etalon element 30 is configured to be able to change the wavelength after the dispersion to an arbitrary wavelength.

< Structure of etalon element >

Next, a specific example of the dispersion of the etalon element 30 and the change of the wavelength of the dispersed light to an arbitrary wavelength will be described with reference to fig. 2 and 3. 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 therebetween. The distance d is called the air gap.

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

As shown in fig. 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.

The driving device 33 of embodiment 1 is configured to include a piezoelectric element. The piezoelectric element is an element driven by utilizing a piezoelectric effect. The distance d changes by applying a voltage to the piezoelectric elements included in the driving device 33 to press the half mirror 31 and the half mirror 32. That is, the control device 50 can change the distance d by adjusting the value of the voltage applied to the piezoelectric element included in the drive device 33.

Thereby, the control device 50 can adjust the wavelength of the cathode emission CL3 to pass 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, an electromagnetic actuator, or the like.

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 enters the half mirror 31. Part of the cathode emission CL2 passes through the half mirror 31. In fig. 3, the cathode luminescence CL2 transmitted through the half mirror 31 is represented as cathode luminescence CLg.

The cathode luminescence CLg repeats reflection between the half mirror 31 and the half mirror 32. The half mirror 31 and the half mirror 32 interfere with each other by reflecting the cathode luminescence CLg a plurality of times, the integral multiple of the wavelength of which is the distance d. By interference, cathodoluminescence CLg of specific wavelengths mutually enhance. This allows only the cathode emission CL3 having a specific wavelength to pass through the half mirror 32 from the etalon element 30.

Fig. 4 is a graph showing an example of the emission intensity of cathodoluminescence emitted from the sample Sp1 in embodiment 1. As described above, the control device 50 calculates the emission intensity of cathodoluminescence at the position of the sample Sp1 to which the electron beam EB1 is irradiated. The control device 50 scans the entire sample Sp1 with the electron beam EB1 to form an image showing the distribution of the emission intensity of cathodoluminescence of the entire sample Sp1.

Fig. 4 shows an example in which the control device 50 displays the formed image Im1 on the display 60. As shown in fig. 4, the display 60 displays the sample Sp1 when viewed from the positive direction side of the Z axis in a plan view.

In the cathodoluminescence spectroscopy apparatus 100 according to embodiment 1, the voltage value applied to the scanning coil 13 is adjusted to change the magnetic field, thereby scanning the electron beam EB1. Thereby, the electron beam EB1 is incident on the entire sample Sp1 when viewed from the positive direction side of the Z axis in a plan view.

The control device 50 forms an image Im1 using the position where the electron beam EB1 is incident and the emission intensity of the cathodoluminescence at the position. In fig. 4, an area Ar1 indicated by a solid line and an area Ar2 indicated by a broken line are shown in the image Im1. The region Ar1 is a region in which the emission intensity of the cathode emission is higher than that of the region Ar2. In addition, the region other than the region Ar1 and the region Ar2 in the image Im1 is a region which is not scanned or a region in which light emission of cathode emission is not detected. The control device 50 may display an image Im1 indicating the emission intensity of the cathodoluminescence superimposed on an image of the sample Sp1 obtained by detecting the secondary electrons.

As described above, in the case of the cathodoluminescence spectroscopy apparatus 100 according to embodiment 1, the emission intensity of cathodoluminescence generated when the sample Sp1 is irradiated with the electron beam EB1 using the etalon element 30 can be visually displayed. As described above, the space required in the case of disposing the etalon element 30 is smaller than the space required in the case of disposing the spectroscopic crystal.

Thus, in the cathodoluminescence spectroscopic apparatus 100 according to embodiment 1, the size of the spectroscope for dispersing cathodoluminescence can be reduced. As a result, the cathode emission spectrometer 100 can be downsized, and other devices can be disposed inside the cathode emission spectrometer 100. Further, since the cost of the etalon element 30 is lower than that of the spectroscopic crystal, the cost of the entire cathodoluminescence spectroscopy apparatus 100 can be reduced.

In the case of performing spectroscopy using a spectroscopic crystal, the wavelength of cathodoluminescence that is subjected to spectroscopy by the spectroscopic crystal varies depending on the angle at which the cathodoluminescence is incident on the spectroscopic crystal. Therefore, in order to obtain a spectrum of each wavelength, it is necessary to perform an operation of changing the angle of the spectroscopic crystal every time of detection. In order to accurately perform the operation of changing the angle of the spectroscopic crystal, it is necessary to appropriately perform zero point correction, and therefore the total time required for performing the spectroscopic operation may be long.

On the other hand, in the case of the cathodoluminescence spectroscopy apparatus 100 according to embodiment 1, the wavelength after the spectroscopy can be easily changed only by adjusting the voltage applied to the piezoelectric element included in the driving device 33. That is, in the case of the cathodoluminescence spectroscopy apparatus 100 according to embodiment 1, the time required for analyzing cathodoluminescence can be reduced as compared with the case of using a spectroscopic crystal.

[ embodiment 2]

In the case of the cathodoluminescence spectroscopy apparatus 100 according to embodiment 1, a configuration is 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 embodiment 2, a configuration for forming an image indicating emission intensity of cathode emission without scanning electron beam EB1 will be described. Note that, in the cathodoluminescence spectroscopy apparatus 100A according to embodiment 2, a description of a configuration overlapping with the cathodoluminescence spectroscopy apparatus 100 according to embodiment 1 will not be repeated.

Fig. 5 is a diagram showing an outline of a cathodoluminescence spectroscopy apparatus 100A according to embodiment 2. The sample Sp1 similar to that in embodiment 1 is placed on the sample stage 15 in embodiment 2. As shown in fig. 5, in cathodoluminescence spectroscopy Device 100A according to embodiment 2, detector 40A for detecting cathodoluminescence CL3 is implemented as a CCD (Charge Coupled Device). The detector 40A as a CCD has a plurality of light receiving elements. The detector 40A and the etalon element 30 may also be provided integrally.

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

Fig. 6 is a perspective view of the sample Sp1 irradiated with the electron beam EB 2. In fig. 6, an electron beam EB2 irradiates an irradiation region Fc1 on the surface of the sample Sp1. The irradiation region Fc1 has a circular shape with a diameter of width Wd. The point Cp indicates the center of the irradiation region Fc1 in a circular shape.

As shown in fig. 6, the irradiation region Fc1 includes a region Fa1, a region Fa2, and a region Fa3. When the electron beam EB2 is irradiated, cathodoluminescence CL11, CL12, and CL13 are emitted from the regions Fa1, fa2, and Fa3, respectively. The cathode emissions CL11, CL12, and CL13 are reflected by the mirror 20 as cathode emissions CL21, CL22, and CL23, and are converged toward the etalon element 30.

Fig. 7 is a perspective view of the etalon element 30 and the detector 40A as a CCD. As shown in fig. 7, the cathode emissions CL21, CL22, and CL23 enter the half mirror 31 of the etalon element 30. By the multiple interference, cathodoluminescence CL31, CL32, and CL33 having specific wavelengths are transmitted through the half mirror 32. The detector 40A as a CCD has a plurality of light receiving elements including light receiving elements LE1, LE2, LE 3.

The cathode emission CL31 is detected by the light receiving element LE 1. The cathode emission CL32 is detected by the light receiving element LE 2. The cathode emission CL33 is detected by the light receiving element LE 3. The detection value of the light receiving element LE1 indicates the emission intensity of the cathodoluminescence in the region Fa 1. The detection value of the light receiving element LE2 indicates the emission intensity of the cathodoluminescence in the region Fa 2. The detection value of the light receiving element LE3 indicates the emission intensity of the cathodoluminescence in the region Fa3. In this way, the cathodoluminescence spectroscopy apparatus 100A according to embodiment 2 can form an image indicating the emission intensity of cathodoluminescence of the entire sample Sp1 without scanning the electron gun 10.

Fig. 8 is a graph showing an example of the emission intensity of cathodoluminescence emitted from the sample Sp1 in embodiment 2. The display 60 displays the image Im2. The image Im2 is an image formed by the control device 50 using the detection result of the detector 40A as the CCD. The region Fd1 in the image Im2 is a region corresponding to the irradiation region Fc1 in fig. 6. Further, the regions Fb1, fb2, fb3 in the image Im2 correspond to the regions Fa1, fa2, fa3 in fig. 6, respectively.

The area Ar1 in fig. 8 corresponds to the area Ar1 in fig. 4. The area Ar2 in fig. 8 corresponds to the area Ar2 in fig. 4. That is, the region Ar1 is a region having the highest emission intensity, and the region Ar2 is a region having a lower emission intensity than the region Ar 1. Further, the region Ar3, which is not the region Ar1 and the region Ar2, in the region Fd1 is a region where light emission of the cathodoluminescence is not detected. Thus, the user can see the image Im2 and recognize that the emission intensity of the detected cathodoluminescence increases in the order of the light receiving elements LE1, LE2, and LE 3.

As described above, also in embodiment 2, by performing light splitting using the etalon element 30, the size and cost of the beam splitter for splitting the cathodoluminescence can be reduced in the cathodoluminescence light-splitting device 100A. As described above, the etalon element 30 performs wavelength scanning of 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 a spectroscope that requires changing the position of the spectroscopic crystal. That is, the analysis time can be shortened in embodiment 2. Further, the cathodoluminescence spectroscopic apparatus 100A according to embodiment 2 forms an image Im2 using a CCD provided with a plurality of light receiving elements and an etalon element 30 capable of simultaneously dispersing a plurality of cathodoluminescence. Accordingly, the controller 50 can form the image Im2 indicating the emission intensity of the cathodoluminescence emitted from the sample Sp1 without scanning the electron gun 10, and can reduce the time required for image formation. Further, by integrating the detector 40A as a CCD and the etalon element 30, the cathodoluminescence spectroscopy device 100A can be further miniaturized.

Furthermore, since it is not necessary to scan the electron beam EB2, energy Dispersive X-ray Spectroscopy (Energy Dispersive X-ray Spectroscopy), wavelength Dispersive X-ray Spectroscopy (Wavelength Dispersive X-ray Spectroscopy), and cathodoluminescence analysis can be performed simultaneously. Further, the spectrum can be detected for each light receiving element included in the detector 40A as a CCD. That is, the cathodoluminescence spectroscopy apparatus 100A according to embodiment 2 can display the regions Ar1 to Ar3 separately according to not only the emission intensity but also the wavelength.

Next, examples of displaying the regions Ar1 to Ar3 in a wavelength-specific manner will be described with reference to fig. 9 to 11. The control device 50 causes the detector 40A to detect the cathode emission CL3 while changing the distance d between the half mirror 31 and the half mirror 32 of the etalon element 30. Thus, each light receiving element of the detector 40A detects the emission intensity of the cathodoluminescence CL3 of a plurality of wavelengths. The plurality of wavelengths can be, for example, wavelengths between 200nm and 1300 nm. Fig. 9 is a diagram illustrating an example of a spectrum of the light receiving element LE3 corresponding to the region Ar1 in fig. 8. As shown in fig. 9, the light receiving element LE3 detects cathode emission CL3 having emission intensity exceeding the threshold Th at a wavelength near 400 nm.

Next, fig. 10 is a diagram illustrating an example of a spectrum of the light receiving element LE2 corresponding to the region Ar2 of fig. 8. As shown in fig. 10, the light receiving element LE2 detects cathode emission CL3 having an emission intensity exceeding the threshold Th at a wavelength near 1000 nm. Fig. 11 is a diagram illustrating an example of a spectrum of the light receiving element LE1 corresponding to the region Ar3 in fig. 8. As shown in fig. 11, the light receiving element LE1 does not detect the cathode emission CL3 having the emission intensity exceeding the threshold Th between the wavelengths of 200nm and 1300 nm. The threshold Th can be determined in advance in accordance with the sensitivity of the detector 40A as a CCD or the like.

In this way, cathodoluminescence spectroscopy apparatus 100A according to embodiment 2 can detect the spectrum of cathodoluminescence CL3 for each light-receiving element included in detector 40A. Therefore, when displaying the image Im2, the cathodoluminescent spectroscopy apparatus 100A according to embodiment 2 can display the regions Ar1 to Ar3 corresponding to the respective light receiving elements differently not only in accordance with the emission intensity but also in accordance with 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.

For example, the control device 50 displays a region corresponding to the light receiving element LE3 that detects high emission intensity at a wavelength near 400nm with a blue color, and displays a region corresponding to the light receiving element LE2 that detects high emission intensity at a wavelength of 1000nm with a red color. In addition, the control device 50 may change the shade of the color to be displayed according to the emission intensity in order to distinguish the light receiving elements that detect the cathodoluminescence exceeding the threshold Th at the same wavelength. In this way, by changing the display method of the region corresponding to the light receiving element in accordance with the emission intensity and wavelength, the cathodoluminescence spectroscopy apparatus 100A according to embodiment 2 enables the user to easily grasp the difference in emission intensity and wavelength for each position on the sample Sp1.

[ embodiment 3]

In the cathodoluminescence spectroscopy apparatus 100A according to embodiment 2, 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 EB 2. In embodiment 3, a configuration in which the arrangement of the electron gun 10 is changed will be described. Note that, in the cathodoluminescence spectroscopy apparatus 100B according to embodiment 3, a description of a configuration overlapping with the cathodoluminescence spectroscopy apparatus 100A according to embodiment 2 will not be repeated.

Fig. 12 is a diagram showing an outline of a cathodoluminescence spectroscopy apparatus 100B according to embodiment 3. As shown in fig. 12, 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 on the sample Sp1 is 0 degree, but in embodiment 3, the electron beam EB is incident on the sample Sp1 at an angle larger than 0 degree. In fig. 12, the condenser lens 25 is disposed between the mirror 20 and the sample Sp1.

Fig. 13 is a diagram for explaining the incident angle of electron beam EB2 in embodiment 3. In embodiment 2 and embodiment 3, the surface of the sample Sp1 placed on the sample stage 15 on the positive Z-axis direction side is parallel to the surface of the sample stage 15. As shown in fig. 6, electron beam EB2 of embodiment 2 enters irradiation region Fc 1. In embodiment 2, the electron beam EB2 passing through the point Cp of the irradiation region Fc1 is incident perpendicularly from the normal direction of the sample stage 15. That is, the incident angle is 0 degrees.

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

As described above, also in embodiment 3, by performing spectroscopy using the etalon element 30, the size of the spectrometer for splitting cathodoluminescence in the cathodoluminescence spectroscopy device 100B can be reduced, the cost can be reduced, and the analysis time can be shortened. In addition, 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 embodiment 3, the electron gun 10 irradiates the sample Sp1 with the electron beam EB2 at an angle greater than 0 degrees and smaller than 90 degrees. This improves the degree of freedom in the arrangement of the electron gun 10. In addition, the mirror 20 does not need to form the opening 20a.

[ embodiment 4]

In the

cathodoluminescence spectroscopy apparatuses

100, 100A, and 100B according to embodiments 1 to 3, the configurations in which the emission intensity of cathodoluminescence is detected using the etalon element 30 are described. In embodiment 4, a configuration including a beam splitter in addition to the etalon element 30 will be described. Note that, in the cathodoluminescence spectroscopy apparatus 100C according to embodiment 4, a description of a configuration overlapping with the cathodoluminescence spectroscopy apparatus 100 according to embodiment 1 will not be repeated.

Fig. 14 is a diagram showing the structure of a cathodoluminescence spectroscopy apparatus 100C according to embodiment 4. Fig. 14 (a) shows an example of performing light splitting using the etalon element 30, and fig. 14 (B) shows an example of performing light splitting using the light splitting crystal 35.

As shown in fig. 14 (a), the cathodoluminescence spectroscopic apparatus 100C includes a spectroscopic crystal 35 as a spectroscope in addition to the etalon element 30 as a spectroscope. The spectroscopic crystal 35 is configured to be able to reflect cathode emission CL3 having a specific wavelength out of cathode emission CL2 condensed by the reflecting mirror 20.

As shown in fig. 14 (a), the cathodoluminescence spectroscopy apparatus 100C further includes a switching mechanism 80. The switching mechanism 80 is configured to be able to switch the light collection destination of the mirror 20 between the etalon element 30 and the spectroscopic crystal 35. The switching mechanism 80 may be, for example, a motor for changing the positions of the etalon element 30 and the spectroscopic crystal 35, or a motor 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 light collection destination of the mirror 20.

Fig. 14 (a) shows a state where the condensing destination of the mirror 20 is the etalon element 30. The detector 40 detects the emission intensity of the cathode emission CL3 dispersed by the etalon element 30. The control device 50 forms an image based on the detection result of the detector 40. An image formed based on the cathode luminescence CL3 after the light splitting using the etalon element 30 corresponds to a "first image" of the present disclosure.

Fig. 14 (B) shows a state after the light-collecting destination of the mirror 20 is switched from the etalon element 30 to the spectroscopic 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. An image formed based on the cathodoluminescence CL3 after the spectroscopy using the spectroscopic crystal 35 corresponds to a "second image" of the present disclosure. The control device 50 can also switch the light-collecting destination of the mirror 20 from the spectroscopic crystal 35 to the etalon element 30.

< regarding wavelength resolution >

Fig. 15 is a diagram showing a spectrum in the case where the etalon element 30 is used. Fig. 16 is a diagram showing a spectrum in the case where the spectroscopic crystal 35 is used. Fig. 15 and 16 show the results of cathodoluminescence analysis performed on the same sample.

As shown in fig. 15 and 16, the waveforms representing the spectra shown as the area Ar3 are different in shape. Specifically, in the case where the etalon element 30 is used, high intensity is shown in a wide wavelength range within the area Rg 1. On the other hand, in the case where the spectroscopic crystal 35 is used, high intensity is shown in the region Rg2 in a wavelength range narrower than that in the case where the etalon element 30 is used. That is, the wavelength resolution of the spectroscopic crystal 35 is higher than the wavelength resolution of the etalon element 30.

In short, analysis using the etalon element 30 can be performed in a shorter time than analysis using the spectroscopic crystal 35, but since the wavelength resolution of the etalon element 30 is lower than that of the spectroscopic crystal 35, accurate detection results may not be obtained.

Therefore, in embodiment 4, the control device 50 performs analysis using the etalon element 30 and then performs analysis using the spectroscopic crystal 35. Fig. 17 is a flowchart showing an analysis process of switching from the etalon element 30 to the spectroscopic crystal 35. As shown in fig. 14 a, the control device 50 performs light splitting using the etalon element 30 (step S1). As described above, when the etalon element 30 is used in the cathodoluminescence spectroscopy apparatus 100C, analysis can be performed in a short time.

The control device 50 forms an image based on the cathode emission CL3 dispersed by the etalon element 30, and displays the image on the display 60 (step S2). At this time, the following case is assumed: it is confirmed that the user of the image displayed in the display 60 desires to detect the emission intensity of the cathodoluminescence more accurately. The cathodoluminescence spectroscopic apparatus 100C according to embodiment 4 can receive a command for switching to the spectroscopic crystal 35 and then performing detection from the input device 70 when the user desires to more accurately detect the luminescence intensity.

The cathode emission spectrometer 100C may receive a command to change the region to be irradiated with or scanned with the electron beam EB1, in addition to a command to perform detection 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 the detection region from the surface of the specimen Sp1.

The control device 50 determines whether or not a command to switch to the spectroscopic crystal 35 is received from the user (step S3). When determining that the command to perform switching has not been received (no in step S3), control device 50 determines whether or not a command to end the analysis process has been received (step S4). When determining that the command to end the analysis process has been received (yes in step S4), control device 50 ends the analysis process. If it is determined that the command to end the analysis process has not been received (no in step S4), control device 50 repeats the process of step S3.

When determining that the command for switching has been received (yes in step S3), the control device 50 switches the light collection destination of the mirror 20 to the spectroscopic crystal 35 (step S5). That is, the control device 50 controls the switching mechanism 80. At this time, when the detection area is received, the control device 50 changes the area where the electron beam EB1 is incident on the sample Sp1 by controlling the angle of the electron beam EB1 by the scanning coil 13 and the reduction by the objective lens 14.

As shown in fig. 14 (B), the control device 50 performs spectroscopy using the spectroscopic crystal 35 (step S6). When the spectroscopic crystal 35 is used, high-wavelength-resolution spectroscopy can be performed. The control device 50 forms an image based on the cathodoluminescence CL3 dispersed by the dispersing crystal 35, and displays the image on the display 60 (step S7).

As described above, also in embodiment 4, the analysis time can be shortened in the cathodoluminescence spectroscopy apparatus 100A by performing spectroscopy using the etalon element 30. In embodiment 4, the mirror 20 further includes a spectroscopic crystal 35, and the light collection destination of the mirror can be switched according to the application. That is, in embodiment 4, after analysis is performed using the etalon element 30 that can perform analysis in a short time, a site that requires more accurate analysis can be analyzed using the spectroscopic crystal 35 with high wavelength resolution, and thus, efficient analysis can be performed.

[ modified examples ]

(1) In embodiment 1, an example in which the etalon element 30 is provided with a driving device is described. However, the cathodoluminescence spectroscopy apparatus 100 may be configured to include the etalon element 30 in which the distance d between the half mirror 31 and the half mirror 32 is fixed. The cathodoluminescence spectroscopy apparatus 100 may include a plurality of etalon elements 30 having different distances d, and the switching mechanism 80 may switch the light collection destination between the plurality of etalon elements 30.

(2) In embodiment 2, an example of displaying the image Im2 based on the emission intensity or wavelength of the cathode emission CL3 detected by the detector 40A as a CCD is described. In the modification, a configuration in which the control device 50 superimposes another image on the image Im2 and displays the superimposed image on the display 60 will be described.

Fig. 18 is a diagram illustrating superimposition of images. As described in embodiment 1, the control device 50 may display an image of the sample Sp1 obtained by detecting the secondary electrons, superimposed on the image Im1. In embodiment 2, the control device 50 may also display an image obtained by detecting secondary electrons, superimposed on the image Im2.

In embodiment 2, a CCD is used as the detector 40A. The CCD can detect not only the reflection of cathodoluminescence but also the reflection light from the sample Sp1 in the case where normal visible light is used as illumination. The control device 50 according to embodiment 2 may display an image of the sample Sp1 obtained by detecting the reflected light when the normal visible light is used as the illumination, by superimposing the image on the image Im2.

An image Im3 shown in (a) of fig. 18 is an image obtained by detecting secondary electrons or an image obtained by detecting reflected light when normal visible light is used as illumination. That is, an image Im3 shown in fig. 18 (a) is obtained without using cathodoluminescence.

Next, fig. 18 (B) shows an image Im4 when the detector 40A as a CCD detects the cathode luminescence CL2 before the light is dispersed by the etalon element 30. In other words, the image Im4 in fig. 18 (B) is obtained by detecting the cathode emission CL2 by the detector 40A in a state where the etalon element 30 is removed in fig. 5. An area Ar4 where the detector 40A detects the light emission of the cathode emission CL2 is shown in the image Im4.

The cathode emission CL2 before being dispersed by the etalon element 30 includes cathode emission having a wavelength longer than that of the cathode emission CL3 after being dispersed by the etalon element 30. For example, although fig. 9 illustrates a spectrum obtained when the etalon element 30 is used to split cathode emission light CL3 having wavelengths of 200nm to 1300nm, cathode emission light CL2 may include cathode emission light having wavelengths other than 200nm to 1300 nm. Therefore, the region Ar4 is a region including the regions Ar1 and Ar2.

The control device 50 can superimpose the image Im3 and the image Im4 on the image Im2 in fig. 8. Image Im5 in fig. 18 (C) is an image obtained by superimposing image Im3 in fig. 18 (a) and image Im4 in fig. 18 (B) on image Im2 in fig. 8. In this way, in fig. 18 (C), an image Im3 acquired without using the cathode emission is superimposed on an image Im2 obtained by detecting the cathode emission CL3. Thus, the cathodoluminescence spectroscopy apparatus 100A enables a user to easily grasp at which portion of the sample Sp1 the cathodoluminescence CL3 after spectroscopy emits light, using an image of the sample Sp1 obtained by reflection of secondary electrons or visible light.

In fig. 18 (C), image Im4 obtained by detecting cathode emission CL2 before the light split is superimposed on image Im2 obtained by detecting cathode emission CL3 after the light split. This enables the user to easily grasp the difference between the emission intensity of cathodoluminescence CL2 before the light split and the emission intensity of cathodoluminescence CL3 after the light split.

For example, when the emission intensity of the dispersed cathode emission CL3 is low and only the dispersed cathode emission CL3 is displayed on the display 60, the user may recognize that the cathode emission itself is not emitting light. However, in the case of the cathodoluminescence spectroscopic device 100A of the modification, by superimposing the image Im4 and the image Im2, the region Ar4 where the cathodoluminescence CL2 before the spectroscopic operation is emitted can be displayed on the display 60, thereby preventing the user from overlooking the cathodoluminescence itself and emitting the light. Further, image Im5 may be an image in which only image Im2 and image Im3 are superimposed, or may be an image in which only image Im2 and image Im4 are superimposed.

(3) In embodiment 4, a configuration in which the switching mechanism 80 switches the light collection destination of the mirror 20 between the spectroscopic crystal 35 and the etalon element 30 is described. However, the cathodoluminescence reflected by the mirror 20 may also be converged to the spectroscopic crystal 35 and the etalon element 30 at the same time. For example, the following may be configured: further, a half mirror is provided at the light-collecting destination of the mirror 20, and the cathode emission light from the mirror 20 is branched to the spectroscopic crystal 35 and the etalon element 30 by the half mirror and collected at the same time.

[ means ]

It will be appreciated by those skilled in the art that the various exemplary embodiments described above are specific examples in the following manner.

A cathodoluminescence spectroscopy apparatus according to a (first) aspect includes: an electron gun for irradiating a sample with an electron beam; a light-condensing mechanism for condensing cathode emission emitted from the sample by irradiating the sample with an electron beam; a light splitting element configured to be capable of splitting the cathodoluminescence condensed by the condensing means; a detector that detects the intensity of cathodoluminescence that has been split by the splitting element; and a control device for receiving the detection result from the detector and controlling the cathodoluminescence spectroscopy device. The light splitting element includes a first half mirror and a second half mirror disposed at a position opposite to the first half mirror. The first half mirror reflects a part of the cathode emission light condensed by the condensing means and transmits a part of the cathode emission light condensed by the condensing means. The second half mirror reflects a part of the cathode emission transmitted through the first half mirror and transmits a part of the cathode emission 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, so that the cathodoluminescence of a specific wavelength is transmitted through the second half mirror. The detector detects the intensity of the cathodoluminescence transmitted through the second half mirror.

According to the spectroscopic apparatus of the first aspect, the time required for analysis can be shortened in the cathodoluminescence spectroscopic apparatus 100A by performing the spectroscopic operation using the etalon element 30.

(second item) in the cathodoluminescence spectroscopy device according to the first item, 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 region of the irradiation region and second cathodoluminescence emitted from a second region of the irradiation region different from the first region. The first light receiving element receives the first cathodoluminescence split by the splitting element. The second light receiving element receives the second cathodoluminescence split by the splitting element.

According to the spectroscopic apparatus of the second aspect, it is possible to form an image indicating the emission intensity of the cathodoluminescence of the entire sample Sp1 without scanning the electron gun 10.

(third) in the cathodoluminescence spectroscopy apparatus according to the second aspect, an incident angle of the electron beam when the electron beam is incident on the sample is larger than 0 degrees and smaller than 90 degrees.

According to the spectroscopic apparatus of the third aspect, the degree of freedom in the arrangement of the electron gun 10 is improved.

(fourth) in the cathodoluminescence spectroscopy apparatus according to any one of the first to third aspects, the spectroscopy element further includes a driving device that changes a distance between the first half mirror and the second half mirror.

The spectroscopic apparatus according to the fourth aspect, the single spectroscopic element can be used to perform the spectroscopic operation into a plurality of wavelengths.

(fifth aspect) the cathodoluminescence spectroscopy apparatus according to the fourth aspect, wherein the driving device includes a piezoelectric element.

The spectroscopic apparatus according to the fifth aspect, the distance between the first half mirror and the second half mirror can be changed accurately and in a short time by the piezoelectric element.

(sixth aspect) the cathodoluminescence spectroscopy device according to any one of the first to fifth aspects, further comprising: a spectroscopic crystal configured to reflect cathodoluminescence of a specific wavelength out of the cathodoluminescence condensed by the condensing means; and a switching mechanism that switches the light collection destination of the light collection mechanism to the spectroscopic crystal or the spectroscopic element.

The optical splitter according to the sixth aspect, the optical splitter can be easily switched depending on the application.

(seventh aspect) in the cathodoluminescence spectroscopy apparatus according to the sixth aspect, the control device forms the first image based on cathodoluminescence that is split by the splitting element, and the control device displays the second image based on cathodoluminescence that is split by the splitting crystal when receiving a command to switch to the splitting crystal.

According to the spectroscopic apparatus of the seventh aspect, after the spectroscopic analysis is performed by the spectroscopic element having a short analysis time, the spectroscopic analysis can be performed by the spectroscopic crystal having a high wavelength resolution.

In addition, the above-described embodiments and modifications include combinations not mentioned in the specification, and it is intended to appropriately combine the configurations described in the embodiments from the beginning of the application within a range where no defect or contradiction occurs.

The embodiments of the present invention have been described, but the embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the appended claims, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Claims

1. A cathodoluminescence spectrometer is provided with:

an electron gun for irradiating a sample with an electron beam;

a light condensing mechanism that condenses cathode emission emitted from the sample by irradiating the sample with the electron beam;

a light splitting element configured to be capable of splitting the cathodoluminescence condensed by the condensing unit;

a detector that detects the intensity of cathodoluminescence that has been split by the light splitting element; and

a control device for receiving the detection result from the detector and controlling the cathodoluminescence spectroscopy device,

wherein the light splitting element includes a first half mirror and a second half mirror disposed at a position opposite to the first half mirror,

the first half mirror reflects a part of the cathode emission light condensed by the condensing unit and transmits a part of the cathode emission light condensed by the condensing unit,

the second half mirror reflects a part of the cathode emission transmitted through the first half mirror and transmits a part of the cathode emission transmitted through the first half mirror,

the first half mirror and the second half mirror cause cathode luminescence between the first half mirror and the second half mirror to interfere, thereby allowing cathode luminescence of a specific wavelength to pass through the second half mirror,

the detector detects the intensity of the cathodoluminescence transmitted through the second half mirror.

2. The cathodoluminescent light-splitting device according to claim 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 spectral element is configured to perform spectroscopy on first cathodoluminescence emitted from a first region of the irradiation regions, and to perform spectroscopy on second cathodoluminescence emitted from a second region of the irradiation regions different from the first region,

the first light receiving element receives the first cathodoluminescence split by the splitting element,

the second light receiving element receives the second cathodoluminescence split by the splitting element.

3. The cathodoluminescent light-splitting device according to claim 2,

an incident angle of the electron beam when incident on the sample is greater than 0 degrees and less than 90 degrees.

4. The cathodoluminescent light-splitting device according to any one of claims 1 to 3,

the spectral element further includes a driving device that changes a distance between the first half mirror and the second half mirror.

5. The cathodoluminescent light-splitting device according to claim 4,

the driving device is configured to include a piezoelectric element.

6. The cathodoluminescence spectroscopy apparatus according to any one of claims 1 to 3, further comprising:

a spectral crystal configured to reflect cathodoluminescence having a specific wavelength among the cathodoluminescence condensed by the condensing unit; and

and a switching mechanism that switches a light collection destination of the light collection mechanism to the spectroscopic crystal or the spectroscopic element.

7. The cathodoluminescent spectroscopy apparatus according to claim 6, wherein,

the control device forms a first image based on cathodoluminescence that has been split by the splitting element,

the control device displays a second image based on cathodoluminescence that has been dispersed by the dispersing crystal when receiving a command to switch to the dispersing crystal.

8. The cathodoluminescence spectroscopy apparatus according to claim 4, further comprising:

9. The cathodoluminescent spectroscopy apparatus according to claim 8, wherein,

the control device displays a second image based on cathodoluminescence that is split by the splitting crystal when receiving a command to switch to the splitting crystal.

10. The cathodoluminescence spectroscopy apparatus according to claim 5, further comprising:

and a switching mechanism that switches a light collection destination of the light collection mechanism to the light-splitting crystal or the light-splitting element.

11. The cathodoluminescent light-splitting device according to claim 10,