CN115938897A - Cathodoluminescence light-splitting device - Google Patents

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 spectroscopic device

technical field

The present disclosure relates to a cathodoluminescence spectroscopic device.

Background technique

Conventionally, there is known a technique for detecting cathodoluminescence emitted from a sample to obtain information such as lattice defects and impurity distribution of the sample.

For example, Japanese Patent Application Laid-Open No. 2000-206046 discloses a cathodoluminescence spectroscopic device that generates cathodoluminescence by irradiating a sample with an electron beam, and then uses a spectroscopic crystal to disperse the cathodoluminescence.

Contents of the invention

In the cathodoluminescence spectroscopic device disclosed in Japanese Patent Laid-Open No. 2000-206046, a spectroscopic crystal is used as a spectroscope, and therefore it is necessary to arrange the spectroscopic crystal itself inside the cathodoluminescent spectroscopic device. Therefore, the cathodoluminescence spectroscopic device needs to provide a space for arranging the spectroscopic crystal, and the spectroscopic device may be increased in size. As a result, there is a concern that the cathodoluminescence spectroscopic device itself may also increase in size.

The present invention was made to solve such a problem, and an object of the present invention is to reduce the size of a spectroscope for splitting cathodoluminescence in a cathodoluminescence spectroscopic device.

The cathodoluminescence spectroscopic device 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 electron beams. The condensing mechanism condenses cathodoluminescence emitted from the sample by irradiating the sample with electron beams. The spectroscopic element is configured to be able to split the cathodoluminescence condensed by the condensing mechanism. The detector detects the intensity of cathodoluminescence that has been split by the spectroscopic element. The control device receives the detection result from the detector to control the cathodoluminescence spectroscopic device. The light splitting element includes a first half mirror and a second half mirror. The second half mirror is arranged at a position opposite to the first half mirror. The first half mirror reflects a part of the cathodoluminescence condensed by the light condensing means, and transmits a part of the cathodoluminescence condensed by the light condensing means. The second half mirror reflects a part of the cathodoluminescence transmitted through the first half mirror, and transmits a part of the cathodoluminescence transmitted through the first half mirror. The first half mirror and the second half mirror interfere cathodoluminescence between the first half mirror and the second half mirror, thereby allowing cathodoluminescence of a specific wavelength to pass through the second half mirror. The detector detects the intensity of cathodoluminescence transmitted through the second half mirror.

The above-mentioned object, characteristics, aspects, and advantages of the present invention, and other objects, characteristics, aspects, and advantages of the present invention will become clear from the following detailed description related to the present invention to be understood in conjunction with the accompanying drawings.

Description of drawings

FIG. 1 is a diagram showing an outline of a cathodoluminescence spectroscopic device according to Embodiment 1. As shown in FIG.

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

FIG. 3 is a diagram showing multiple interferences of etalon elements.

4 is a diagram showing a display example of the luminescence intensity of cathodoluminescence emitted from a sample in Embodiment 1. FIG.

FIG. 5 is a diagram showing an outline of a cathodoluminescence spectroscopic device according to Embodiment 2. FIG.

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

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

8 is a diagram showing a display example of the luminescence intensity of cathodoluminescence emitted from a sample in Embodiment 2. FIG.

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

FIG. 10 is a graph showing an example of a spectrum of a light receiving element corresponding to the region in FIG. 8 .

FIG. 11 is a graph showing an example of a spectrum of a light receiving element corresponding to the region in FIG. 8 .

FIG. 12 is a diagram showing an outline of a cathodoluminescence spectroscopic device according to Embodiment 3. FIG.

FIG. 13 is a diagram for explaining incident angles of electron beams in Embodiment 3. FIG.

FIG. 14 is a diagram showing the configuration of a cathodoluminescence spectroscopic device according to Embodiment 4. FIG.

FIG. 15 is a graph showing spectra when an etalon element is used.

FIG. 16 is a graph showing spectra when a spectroscopic crystal is used.

FIG. 17 is a flowchart showing analysis processing for switching from an etalon element to a spectroscopic crystal.

FIG. 18 is a diagram illustrating superimposition of images.

Detailed ways

[Embodiment 1]

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code|symbol is attached|subjected to the same or corresponding part in a figure, and the description is not repeated.

<Overall structure of cathodoluminescence spectroscopic device>

FIG. 1 is a diagram showing an outline of a cathodoluminescence spectroscopic device 100 according to Embodiment 1. As shown in FIG. The cathodoluminescence spectroscopy device 100 of Embodiment 1 is, for example, a scanning electron microscope (Scanning Electron Microscope) that scans an electron beam to irradiate a sample. In addition, the cathodoluminescence spectroscopy device 100 is not limited to an electron microscope, and any device may be used as long as it can irradiate a sample with an electron beam.

The cathodoluminescence spectroscopy device 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 scan coil 13 , and an objective lens 14 .

Note that, 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 figure may be referred to as the upper surface side, and the negative direction may be referred to as the lower surface side.

The electron gun 10 irradiates the electron beam EB1 to the sample Sp1 placed on the sample stage 15 . 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 arranged between the electron gun 10 and the sample Sp1. The electron beam EB1 enters the sample Sp1 after passing through the opening 20 a 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. The condenser lens 12 converges the electron beam EB1. The scanning coil 13 scans the electron beam EB1 on the sample Sp1. The objective lens 14 reduces the electron beam EB1 to a minute diameter.

The electron gun 10 is accommodated in a housing connected with a vacuum exhaust mechanism so that the electron source 11 can generate an electron beam EB1. That is, the housing maintains a degree of vacuum at which the electron source 11 can generate electrons.

By irradiating the sample Sp1 with the electron beam EB1 , the electrons in the valence band of the sample Sp1 are excited to the conduction band. The resulting holes recombine with electrons, thereby generating light emission. This luminescence is called cathode luminescence (Cathodoluminescence). Cathodoluminescence was emitted in all directions from the sample Sp1. Additionally, cathodoluminescence encompasses multiple wavelengths. The cathodoluminescence CL1 in FIG. 1 is the cathodoluminescence radiated toward the reflecting mirror 20 among the cathodoluminescence radiated in all directions. That is, cathodoluminescence CL1 is cathodoluminescence from the sample Sp1 to the mirror 20 .

The reflecting mirror 20 reflects the cathodoluminescence CL1 emitted from the sample Sp1. The reflecting mirror 20 reflects the cathodoluminescence CL1 as the cathodoluminescence CL2. The cathodoluminescence CL2 is condensed to the etalon element 30 by the condensing lens 25 . That is, the cathodoluminescence CL2 is cathodoluminescence after being reflected by the mirror 20 until being converged on the etalon element 30 . In addition, the reflecting mirror 20 and the condensing lens 25 correspond to a "condensing mechanism" of the present disclosure. The reflective mirror 20 and the condensing lens 25 as the condensing mechanism may also be integrally provided as a mirror lens.

The etalon element 30 is configured to be able to split the cathodoluminescence CL2 collected by the reflecting mirror 20 and the condenser lens 25 . That is, the etalon element 30 is a spectroscope that transmits only the cathodoluminescence CL2 of a specific wavelength among the cathodoluminescence CL2 including a plurality of wavelengths as the cathodoluminescence CL3 . Hereinafter, the wavelength of the cathodoluminescence CL3 may be referred to as a "spectral wavelength". The etalon element 30 is known as a Fabry-Perot interferometer. The etalon element 30 corresponds to a "spectroscopy element" of the present disclosure.

The dimension of the etalon element 30 in the longitudinal direction is about 5 mm to 15 mm, and the dimension in the width direction is about 1 mm to 5 mm. On the other hand, a general dichroic crystal for splitting cathodoluminescence has a size larger than that of an etalon element. In addition, the cathodoluminescence spectroscopic device including the spectroscopic crystal needs to include an optical system for splitting light by the spectroscopic crystal. The dimension of the beam splitter which houses the optical system and the beam splitting crystal is about 1500 mm to 2500 mm in the longitudinal direction, and about 1500 mm to 2500 mm in the width direction. That is, the space required for arranging the etalon element 30 is smaller than the space required for arranging a spectroscopic crystal.

The detector 40 detects the intensity of the cathodoluminescence CL3 that has been split by the etalon element 30 . The detector 40 of Embodiment 1 is a photomultiplier (PMT). That is, the detector 40 is a so-called photomultiplier tube. The detector 40 multiplies photoelectrons using a plurality of dynodes provided inside, and detects the intensity of minute light.

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

The control device 50 is electrically connected to the display 60 and the input device 70 . The control device 50 displays, for example, information on cathodoluminescence spectroscopy on the display 60 . The information related to cathodoluminescence spectroscopy includes, for example, detection results by the detector 40, error information generated in the analyzer, and the like. The control device 50 receives commands input by the user using the input device 70 . The input device 70 is, for example, a keyboard. The display 60 and the input device 70 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 cathodoluminescence spectroscopy device 100 and configured to communicate bidirectionally with the cathodoluminescence spectroscopy device 100 .

The control device 50 controls the cathodoluminescence spectroscopic device 100 in a unified manner. The control device 50 receives detection values from the detector 40 . The control device 50 calculates the luminescence 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 . Thus, the control device 50 can form an image showing the distribution of the emission intensity of cathodoluminescence in the sample Sp1. The control device 50 displays the formed image on the display 60 . The etalon element 30 is configured to be able to change the split wavelength to an arbitrary wavelength.

<Structure of etalon elements>

Next, a specific example of splitting light by the etalon element 30 and changing the split wavelength to an arbitrary wavelength will be described with reference to FIGS. 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 arranged at positions facing each other with a distance d between them. The distance d is called the air gap.

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

As shown in FIG. 2 , the etalon element 30 includes a driving device 33 arranged 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 according to Embodiment 1 is configured to include a piezoelectric element. A piezoelectric element is an element driven by the piezoelectric effect. The distance d is changed by applying a voltage to the piezoelectric element 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 voltage value applied to the piezoelectric element included in the drive device 33 .

Accordingly, the control device 50 can adjust the wavelength of the cathodoluminescence CL3 that passes through the etalon element 30 . In addition, the drive device 33 may change the distance d without using a piezoelectric element. For example, the driving device 33 may include a motor, an electromagnetic actuator, or the like.

FIG. 3 is a diagram illustrating multiple interference of etalon elements 30 . As shown in FIG. 3 , the cathodoluminescence CL2 reflected by the reflecting mirror 20 enters the half mirror 31 . Part of the cathodoluminescence CL2 passes through the half mirror 31 . In FIG. 3 , cathodoluminescence CL2 transmitted through the half mirror 31 is represented as cathodoluminescence CLg.

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 interfere by reflecting cathodoluminescence CLg whose wavelength is an integral multiple of the distance d multiple times. Cathodoluminescence CLg of specific wavelengths are mutually enhanced by interference. Thereby, the etalon element 30 can transmit only the cathodoluminescence CL3 of a specific wavelength through the half mirror 32 .

4 is a diagram showing an example display of the luminescence intensity of cathodoluminescence emitted from the sample Sp1 in Embodiment 1. FIG. As described above, the control device 50 calculates the emission intensity of the cathodoluminescence at the position irradiated with the electron beam EB1 in the sample Sp1. 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 sample Sp1 is displayed on the display 60 when viewed from the positive direction side of the Z axis.

In the cathodoluminescence spectroscopy device 100 according to Embodiment 1, the voltage value applied to the scanning coil 13 is adjusted to change the magnetic field, whereby the electron beam EB1 scans. As a result, the electron beam EB1 enters the entirety of the sample Sp1 when viewed in plan from the positive Z-axis direction side.

The control device 50 forms the image Im1 using the position where the electron beam EB1 is incident and the luminous 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 dotted line are shown in the image Im1 . The region Ar1 is a region in which the emission intensity of cathodoluminescence is higher than that of the region Ar2. In addition, regions other than the region Ar1 and the region Ar2 in the image Im1 are regions that are not scanned or regions in which luminescence of cathodoluminescence is not detected. The control device 50 may superimpose and display the image Im1 showing the emission intensity of cathodoluminescence on the image of the sample Sp1 obtained by detecting the secondary electrons.

In this manner, in the case of the cathodoluminescence spectroscopic apparatus 100 according to Embodiment 1, it is possible to 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 a spectroscopic crystal.

Thus, in the cathodoluminescence spectroscopic device 100 according to Embodiment 1, it is possible to reduce the size of the spectroscope for splitting cathodoluminescence. As a result, it is possible to reduce the size of the cathodoluminescence spectroscopic device 100 or to arrange other devices inside the cathodoluminescence spectroscopic device 100 . In addition, the cost of the etalon element 30 is lower than the cost of the spectroscopic crystal, so the overall cost of the cathodoluminescence spectroscopic device 100 can be reduced.

In the case of using a dichroic crystal for splitting light, the wavelength of cathodoluminescence that is split by the dichroic crystal changes depending on the angle at which the cathodoluminescence is incident on the dichroic crystal. Therefore, in order to obtain the spectrum of each wavelength, it is necessary to change the angle of the spectroscopic crystal every detection. In order to accurately perform the operation of changing the angle of the spectroscopic crystal, it is necessary to perform zero-point calibration appropriately, and therefore the total time required for spectroscopic performance may be long.

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

[Embodiment 2]

In the case of the cathodoluminescence spectroscopic device 100 according to Embodiment 1, a configuration is described in which the emission intensity of cathodoluminescence on the entire surface of the sample Sp1 is detected by scanning the electron beam EB1 . In Embodiment 2, the structure which forms the image which shows the emission intensity of cathodoluminescence without scanning the electron beam EB1 is demonstrated. In addition, in the cathodoluminescence spectroscopic device 100A of Embodiment 2, the description of the configuration that overlaps with that of the cathodoluminescence spectroscopic device 100 of Embodiment 1 will not be repeated.

FIG. 5 is a diagram showing an outline of a cathodoluminescence spectroscopic device 100A according to Embodiment 2. FIG. On the sample stand 15 of the second embodiment, the same sample Sp1 as that of the first embodiment is placed. As shown in FIG. 5 , in the cathodoluminescence spectroscopic apparatus 100A of the second embodiment, the detector 40A for detecting the cathodoluminescence CL3 is implemented as a CCD (Charge Coupled Device: Charge Coupled Device). Detector 40A, which is a CCD, has a plurality of light receiving elements. The detector 40A and the etalon element 30 may also be provided integrally.

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

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

As shown in FIG. 6 , the irradiation area Fc1 includes an area Fa1 , an area Fa2 , and an area Fa3 . Cathodoluminescence CL11 , CL12 , and CL13 are emitted from the regions Fa1 , Fa2 , and Fa3 by being irradiated with the electron beam EB2 . The cathodoluminescence CL11 , CL12 , and CL13 are reflected by the mirror 20 as cathodoluminescence CL21 , CL22 , and CL23 , and converge 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 , cathodoluminescence CL21 , CL22 , and CL23 enter the half mirror 31 of the etalon element 30 . Cathodoluminescence CL31 , CL32 , and CL33 of specific wavelengths are transmitted through the half mirror 32 by multiple interference. Detector 40A which is a CCD has a some light receiving element including light receiving element LE1, LE2, LE3.

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 detected value of the light receiving element LE1 indicates the emission intensity of the cathodoluminescence in the region Fa1. The detection value of the light receiving element LE2 shows the emission intensity of the cathodoluminescence in the region Fa2. The detection value of the light receiving element LE3 shows the emission intensity of the cathodoluminescence in the region Fa3. In this way, the cathodoluminescence spectroscopic apparatus 100A of Embodiment 2 can form an image showing the emission intensity of the cathodoluminescence of the entire sample Sp1 without scanning the electron gun 10 .

FIG. 8 is a diagram showing a display example of the luminescence intensity of cathodoluminescence emitted from the sample Sp1 according to Embodiment 2. FIG. 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 which is a CCD. The area Fd1 in the image Im2 is an area corresponding to the shot area Fc1 in FIG. 6 . In addition, the regions Fb1 , Fb2 , and Fb3 in the image Im2 correspond to the regions Fa1 , Fa2 , and Fa3 in FIG. 6 , respectively.

The region Ar1 in FIG. 8 corresponds to the region Ar1 in FIG. 4 . The region Ar2 in FIG. 8 corresponds to the region Ar2 in FIG. 4 . That is, the region Ar1 is a region with the highest luminous intensity, and the region Ar2 is a region with a lower luminous intensity than the region Ar1. In addition, a region Ar3 other than the region Ar1 and the region Ar2 in the region Fd1 is a region where cathodoluminescence is not detected and emits light. Thereby, the user can observe the image Im2 and grasp that the luminous intensity of the detected cathodoluminescence becomes higher in the order of the light receiving elements LE1 , LE2 , and LE3 .

In this way, also in Embodiment 2, by performing light splitting using the etalon element 30 , it is possible to reduce the size and cost of the spectroscope for splitting cathodoluminescence in the cathodoluminescence spectroscopic device 100A. In addition, as described above, the etalon element 30 performs wavelength scanning of light using the driving device 33 including a piezoelectric element. Therefore, the analysis time when using the etalon element 30 is shorter than the analysis time when using a spectroscope that requires changing the position of the spectroscopic crystal. That is, the analysis time can also be shortened in the second embodiment. Furthermore, the cathodoluminescence spectroscopic device 100A of Embodiment 2 forms an image Im2 using a CCD including a plurality of light receiving elements and an etalon element 30 capable of simultaneously splitting a plurality of cathodoluminescence. Accordingly, the control device 50 can form the image Im2 showing the luminescence intensity of the cathodoluminescence emitted from the sample Sp1 without scanning the electron gun 10 , and the time required for image formation can be reduced. In addition, by integrating the detector 40A as a CCD and the etalon element 30 , it is possible to further reduce the size of the cathode luminescence spectroscopy device 100A.

Furthermore, since it is not necessary to scan the electron beam EB2, energy dispersive X-ray Spectroscopy, wavelength dispersive X-ray Spectroscopy, and cathodoluminescence analysis can be performed simultaneously. In addition, it is 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 according to Embodiment 2 can distinguish and display the regions Ar1 to Ar3 not only according to the emission intensity but also according to the wavelength.

Next, an example in which the regions Ar1 to Ar3 are displayed according to wavelengths will be described with reference to FIGS. 9 to 11 . The control device 50 causes the detector 40A to detect the cathodoluminescence CL3 while changing the distance d between the half mirror 31 and the half mirror 32 of the etalon element 30 . Thereby, 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 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 in FIG. 8 . As shown in FIG. 9 , the light receiving element LE3 detects cathodoluminescence CL3 having a luminous intensity exceeding the threshold Th at a wavelength around 400 nm.

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 , the light receiving element LE2 detects cathodoluminescence CL3 having a luminous intensity exceeding the threshold Th at a wavelength around 1000 nm. 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 , the light-receiving element LE1 did not detect cathodoluminescence CL3 having a luminescence intensity exceeding the threshold value Th between wavelengths of 200 nm to 1300 nm. The threshold Th can be determined in advance according to the sensitivity of the detector 40A which is a CCD, and the like.

In this way, the cathodoluminescence spectroscopy device 100A of Embodiment 2 can detect the spectrum of the cathodoluminescence CL3 for each light receiving element included in the detector 40A. Therefore, when displaying the image Im2, the cathodoluminescence spectroscopic device 100A of Embodiment 2 can display the regions Ar1 to Ar3 corresponding to the light receiving elements not only differently according to the luminous intensity but also differently according to the wavelength. Specifically, the control device 50 displays the color corresponding to the detected wavelength on the image Im2 on the display 60 shown in FIG. 8 .

For example, the control device 50 marks and displays in blue the region corresponding to the light receiving element LE3 that detected a high luminous intensity at a wavelength near 400 nm, and displays the area corresponding to the light receiving element LE2 that detected a high luminous intensity at a wavelength of 1000 nm. Regions are marked in red for display. In addition, the control device 50 may change the intensity of the displayed color according to the luminous intensity in order to distinguish the light-receiving elements that have detected 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 according to the luminous intensity and wavelength, the cathodoluminescence spectroscopic device 100A of Embodiment 2 can allow the user to easily grasp the difference in luminous intensity and wavelength for each position on the sample Sp1. .

[Embodiment 3]

In the cathodoluminescence spectroscopic apparatus 100A according to Embodiment 2, a configuration is described in which the emission intensity of cathodoluminescence is detected using the detector 40A including a plurality of light receiving elements without scanning the electron beam EB2 . In Embodiment 3, a configuration in which the arrangement of the electron gun 10 is changed will be described. In addition, in the cathodoluminescence spectroscopic device 100B of Embodiment 3, the description of the structure that overlaps with that of the cathodoluminescence spectroscopic device 100A of Embodiment 2 will not be repeated.

FIG. 12 is a diagram showing an outline of a cathodoluminescence spectroscopic device 100B according to Embodiment 3. As shown in FIG. As shown in FIG. 12 , the electron gun 10 is arranged at a position separated 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 angle of 0°, but in the third embodiment, the electron beam EB is incident on the sample Sp1 at an angle greater than 0°. In FIG. 12 , the condenser lens 25 is arranged between the reflection mirror 20 and the sample Sp1.

FIG. 13 is a diagram for explaining the incident angle of the electron beam EB2 according to the third embodiment. 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 , the electron beam EB2 according to Embodiment 2 enters the irradiation region Fc1 . In Embodiment 2, the electron beam EB2 passing through the point Cp of the irradiation region Fc1 is incident vertically 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 enters the sample Sp1 at the incident angle θ. The incident angle θ is an angle larger than 0 degrees and smaller than 90 degrees.

In this way, also in Embodiment 3, by performing light splitting using the etalon element 30 , it is possible to reduce the size of the spectroscope for splitting the cathodoluminescence in the cathodoluminescence spectroscopic apparatus 100B, reduce the cost, and shorten the analysis time. 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 so that the angle at which the electron beam EB2 enters the sample Sp1 is greater than 0 degrees and less than 90 degrees. Accordingly, the degree of freedom in arrangement of the electron gun 10 is improved. In addition, the reflecting mirror 20 does not need to form the opening 20a.

[Embodiment 4]

In the cathodoluminescence spectroscopic devices 100 , 100A, and 100B according to Embodiments 1 to 3, a configuration in which the emission intensity of cathodoluminescence is detected using the etalon element 30 has been described. In Embodiment 4, a configuration including a beam splitter in addition to the etalon element 30 will be described. In addition, in the cathodoluminescence spectroscopic device 100C of Embodiment 4, the description of the structure that overlaps with that of the cathodoluminescence spectroscopic device 100 of Embodiment 1 will not be repeated.

FIG. 14 is a diagram showing the configuration of a cathodoluminescence spectroscopic device 100C according to Embodiment 4. FIG. (A) of FIG. 14 shows an example of splitting light using an etalon element 30 , and (B) of FIG. 14 shows an example of splitting light using a splitting crystal 35 .

As shown in (A) of FIG. 14 , a cathodoluminescence spectroscopic device 100C includes a spectroscopic crystal 35 as a spectroscope in addition to the etalon element 30 as the spectroscope. The dichroic crystal 35 is configured to be able to reflect the cathodoluminescence CL3 of a specific wavelength among the cathodoluminescence CL2 converged by the reflecting mirror 20 .

As shown in (A) of FIG. 14 , the cathodoluminescence spectroscopic device 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 dichroic crystal 35 . The switching mechanism 80 may be, for example, a motor or the like for changing the positions of the etalon element 30 and the dichroic crystal 35 , or may be a motor or the like for changing the angle of the mirror 20 . The switching mechanism 80 is electrically connected to the control device 50 . The control device 50 controls the switching mechanism 80 to switch the light-collecting destination of the reflecting mirror 20 .

(A) of FIG. 14 shows a state where the focusing destination of the mirror 20 is the etalon element 30 . The detector 40 detects the luminescence intensity of the cathodoluminescence CL3 that has been split 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 spectroscopically split using the etalon element 30 corresponds to the “first image” of the present disclosure.

FIG. 14(B) shows a state after the light-condensing destination of the mirror 20 is switched from the etalon element 30 to the dichroic crystal 35 . The detector 40 detects the intensity of the cathodoluminescence CL3 that has been split by the spectroscopic crystal 35 . The control device 50 forms an image based on the detection result of the detector 40 . The image formed based on the cathodoluminescence CL3 after being spectroscopically split using the spectroscopic crystal 35 corresponds to the “second image” of the present disclosure. The control device 50 can also switch the focus destination of the mirror 20 from the dichroic crystal 35 to the etalon element 30 .

<About wavelength resolution>

FIG. 15 is a graph showing spectra when the etalon element 30 is used. FIG. 16 is a graph showing a spectrum when the spectroscopic crystal 35 is used. The results obtained by cathodoluminescence analysis of the same sample are shown in FIGS. 15 and 16 .

As shown in FIG. 15 and FIG. 16 , the shapes of the waveforms representing the spectra shown as the region Ar3 are different. Specifically, when the etalon element 30 is used, high intensity is shown in a wide wavelength range in the region Rg1. On the other hand, in the case of using the dichroic crystal 35 , in the region Rg2 , high intensity is shown in a narrower wavelength range than that in the case of using the etalon element 30 . That is, the wavelength resolution of the dichroic crystal 35 is higher than that of the etalon element 30 .

In short, the analysis using the etalon element 30 can be performed in a shorter time than the 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 , so sometimes accurate detection results cannot be obtained.

Therefore, in Embodiment 4, the control device 50 performs analysis using the spectroscopic crystal 35 after performing analysis using the etalon element 30 . FIG. 17 is a flowchart showing analysis processing for switching from the etalon element 30 to the spectroscopic crystal 35 . As shown in (A) of FIG. 14 , the control device 50 performs light splitting using the etalon element 30 (step S1 ). As described above, the cathodoluminescence spectroscopic apparatus 100C can perform analysis in a short time when using the etalon element 30 .

The control device 50 forms an image based on the cathodoluminescence CL3 spectroscopically separated using the etalon element 30 , and displays the image on the display 60 (step S2 ). At this time, it is assumed that the user who confirmed the image displayed on the display 60 desires to detect more accurately the emission intensity of cathodoluminescence. The cathodoluminescence spectroscopic device 100C according to Embodiment 4 can receive a command from the input device 70 to switch to the spectroscopic crystal 35 and perform detection when the user desires to detect more accurately the luminous intensity.

The cathodoluminescence spectroscopic apparatus 100C may receive an order to change the area to be irradiated or scanned by the electron beam EB1 in addition to an order to switch to the spectroscopic crystal 35 to perform detection. That is, when it is desired to detect only a part of the images displayed in step S2 by the spectroscopic crystal 35 , the user can select a detection region from the surface of the sample Sp1 .

The control device 50 judges whether or not a command to switch to the light splitting crystal 35 has been received from the user (step S3). When the control device 50 determines that the command to switch has not been received ("No" in step S3), it determines whether or not the command to end the analysis process has been received (step S4). When the control device 50 determines that an instruction to end the analysis process has been received (YES in step S4 ), it ends the analysis process. When the control device 50 determines that the command to end the analysis process has not been received ("No" in step S4), the process of step S3 is repeated.

When the control device 50 determines that the command to switch has been received (YES in step S3 ), it switches the light-condensing destination of the reflecting mirror 20 to the dichroic crystal 35 (step S5 ). That is, the control device 50 controls the switching mechanism 80 . At this time, when receiving the detection area, the control device 50 controls the angle of the electron beam EB1 by the scanning coil 13 and the reduction by the objective lens 14 to change the incident area of the electron beam EB1 on the sample Sp1.

As shown in (B) of FIG. 14 , the control device 50 performs light-splitting using the light-splitting crystal 35 (step S6 ). When the spectroscopic crystal 35 is used, it is possible to perform spectroscopic separation with high wavelength resolution. The control device 50 forms an image based on the cathodoluminescence CL3 that has been split by the spectroscopic crystal 35, and displays the image on the display 60 (step S7).

In this way, also in Embodiment 4, analysis time can be shortened in the cathodoluminescence spectroscopy apparatus 100A by performing spectroscopy using the etalon element 30 . Furthermore, in Embodiment 4, a dichroic crystal 35 is further provided, and the light-collecting destination of the reflecting mirror 20 can be switched according to the application. That is, in Embodiment 4, after the analysis is performed using the etalon element 30 that can be analyzed in a short time, the spectroscopic crystal 35 with high wavelength resolution can be used to analyze the site requiring more accurate analysis, so it is possible Perform efficient analysis.

[modified example]

(1) In Embodiment 1, an example in which the etalon element 30 is provided with a driving device has been described. However, the cathodoluminescence spectroscopic device 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 spectroscopic device 100 may include a plurality of etalon elements 30 having different distances d, and the light focusing destination may be switched among the plurality of etalon elements 30 by the switching mechanism 80 .

(2) In Embodiment 2, an example in which the image Im2 is displayed based on the emission intensity or the wavelength of the cathodoluminescence CL3 detected by the detector 40A which is a CCD has been described. In a modified example, a configuration in which the control device 50 superimposes another image on the image Im2 and displays it 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 superimpose and display the image of the sample Sp1 obtained by detecting secondary electrons on the image Im1. In addition, also in Embodiment 2, the control device 50 may superimpose and display an image obtained by detecting secondary electrons on the image Im2.

In Embodiment 2, a CCD is used as the detector 40A. The CCD is capable of detecting not only reflection of cathodoluminescence but also reflected light from the sample Sp1 when ordinary visible light is used as illumination. The control device 50 of Embodiment 2 may superimpose and display the image of the sample Sp1 obtained by detecting reflected light when ordinary visible light is used as illumination, on the image Im2.

The 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 ordinary visible light is used as illumination. That is, the image Im3 shown in (A) of FIG. 18 is acquired without using cathodoluminescence.

Next, in (B) of FIG. 18 , an image Im4 when the detector 40A that is a CCD detects the cathodoluminescence CL2 before being spectroscopically separated by the etalon element 30 is shown. In other words, the image Im4 of (B) of FIG. 18 is obtained by detecting the cathodoluminescence CL2 with the detector 40A in the state where the etalon element 30 is removed in FIG. 5 . The image Im4 shows a region Ar4 where the detector 40A detects the light emission of the cathodoluminescence CL2 .

The cathodoluminescence CL2 before being spectroscopically split by the etalon element 30 includes cathodoluminescence having a longer wavelength than the cathodoluminescence CL3 after spectroscopically splitting by the etalon element 30 . For example, in FIG. 9 , the spectrum when the etalon element 30 is used to split the cathodoluminescence CL3 into wavelengths of 200 nm to 1300 nm is described, but the cathodoluminescence CL2 can also include cathodoluminescence with wavelengths other than 200 nm 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 of FIG. 8 . The image Im5 in (C) of FIG. 18 is an image after the image Im3 of (A) of FIG. 18 and the image Im4 of (B) of FIG. 18 are superimposed on the image Im2 of FIG. 8 . Thus, in (C) of FIG. 18 , the image Im3 acquired without using cathodoluminescence is superimposed on the image Im2 obtained by detecting cathodoluminescence CL3 . Thus, the cathodoluminescence spectroscopic apparatus 100A enables the user to easily grasp at which part of the sample Sp1 the spectroscopic cathodoluminescence CL3 emits light using the image of the sample Sp1 obtained by reflection of secondary electrons or visible light.

In addition, in (C) of FIG. 18 , the image Im4 obtained by detecting the cathodoluminescence CL2 before the spectroscopy is superimposed on the image Im2 obtained by detecting the cathodoluminescence CL3 after the spectroscopy. This allows the user to easily grasp the difference between the light emission intensity of the cathodoluminescence CL2 before spectral separation and the light emission intensity of the cathodoluminescence CL3 after spectral separation.

For example, when the light emission intensity of the split cathodoluminescence CL3 is low and only the split cathodoluminescence CL3 is displayed on the display 60 , the user may recognize that the cathodoluminescence itself is not emitting light. However, in the case of the cathodoluminescence spectroscopic device 100A of the modified example, by superimposing the image Im4 and the image Im2, the region Ar4 where the cathodoluminescence CL2 emits light before the spectroscopic analysis can be displayed on the display 60, thereby preventing the user from missing the progress of the cathodoluminescence itself. Glowing situation. In addition, the image Im5 may be an image formed only by superimposing the image Im2 and the image Im3, or may be an image formed only by superimposing the image Im2 and the image Im4.

(3) In Embodiment 4, the structure in which the switching mechanism 80 switches the light-condensing destination of the mirror 20 between the dichroic crystal 35 and the etalon element 30 has been described. However, the cathodoluminescence reflected by the mirror 20 may also be converged to the dichroic crystal 35 and the etalon element 30 at the same time. For example, a half mirror may also be provided at the condensing destination of the reflecting mirror 20, and the cathodoluminescence from the reflecting mirror 20 may be branched to the dichroic crystal 35 and the etalon element 30 by using the half mirror. simultaneously converged.

[Way]

Those skilled in the art can understand that the above exemplary embodiments are specific examples of the following aspects.

(Claim 1) A cathodoluminescence spectroscopic device according to one aspect includes: an electron gun for irradiating an electron beam to a sample; an element configured to be able to split the cathodoluminescence converged by the light converging mechanism; a detector to detect the intensity of the cathodoluminescence split by the spectroscopic element; and a control device to receive the detection result from the detector to control Cathodoluminescence spectroscopic device. The light splitting element includes a first half mirror and a second half mirror disposed at a position facing the first half mirror. The first half mirror reflects a part of the cathodoluminescence condensed by the light condensing means, and transmits a part of the cathodoluminescence condensed by the light condensing means. The second half mirror reflects a part of the cathodoluminescence transmitted through the first half mirror, and transmits a part of the cathodoluminescence transmitted through the first half mirror. The first half mirror and the second half mirror interfere cathodoluminescence between the first half mirror and the second half mirror, thereby allowing cathodoluminescence of a specific wavelength to pass through the second half mirror. The detector detects the intensity of cathodoluminescence transmitted through the second half mirror.

According to the spectroscopic device described in the first clause, by performing spectroscopic analysis using the etalon element 30 , analysis time can be shortened in the cathodoluminescence spectroscopic device 100A.

(Item 2) In the cathodoluminescence spectroscopic device according to the first item, the detector includes a first light receiving element and a second light receiving element. The electron gun irradiates electron beams to the irradiation area on the surface of the sample. The spectroscopic element splits first cathodoluminescence emitted from a first region in the irradiation region, and splits second cathodoluminescence emitted from a second region different from the first region in the irradiation region. The first light-receiving element receives the first cathodoluminescence after being split by the light-splitting element. The second light-receiving element receives the second cathodoluminescence after being split by the light-splitting element.

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

(Third Item) In the cathodoluminescence spectroscopic device according to the second item, the incident angle of the electron beam when incident on the sample is larger than 0° and smaller than 90°.

According to the spectroscopic device described in the third item, the degree of freedom in arrangement of the electron gun 10 is improved.

(Item 4) In the cathodoluminescence spectroscopic device according to any one of Items 1 to 3, the spectroscopic element further includes a drive device that drives the first half mirror and the second half mirror The distance between changes.

According to the spectroscopic device described in claim 4, it is possible to split light into a plurality of wavelengths using a single spectroscopic element.

(5th item) In the cathodoluminescence spectroscopic device according to the 4th item, the driving device is configured to include a piezoelectric element.

According to the spectroscopic device described in item 5, the distance between the first half mirror and the second half mirror can be accurately and shortly changed by the piezoelectric element.

(Sixth Item) The cathodoluminescence spectroscopic device according to any one of Items 1 to 5, further comprising: a spectroscopic crystal configured to enable specific cathodoluminescent reflection of the wavelength; and a switching mechanism, which switches the light-gathering destination of the light-gathering mechanism to a light-splitting crystal or a light-splitting element.

According to the spectroscopic device described in the sixth item, it is possible to easily switch the spectroscope according to the application.

(Item 7) In the cathodoluminescence spectroscopic device according to Item 6, the control device forms the first image based on the cathodoluminescence after spectroscopic separation by the spectroscopic element, and when the control device receives a command to switch to a spectroscopic crystal, , displaying the second image based on cathodoluminescence after light splitting by the light splitting crystal.

According to the spectroscopic device described in claim 7, after the spectroscopic element has a short analysis time, the spectroscopic crystal can perform spectroscopic splitting with a high wavelength resolution.

In addition, with respect to the above-mentioned embodiments and modified examples, including combinations not mentioned in the specification, it is intended that the configurations described in the embodiments be appropriately adapted from the beginning of the application within the range that does not cause disadvantages or contradictions. combination.

Although the embodiment of the present invention has been described, it should be understood that the embodiment disclosed this time is an illustration and not restrictive in any respect. The scope of the present invention is shown by the claims, and it is intended that all modifications within the meaning and range equivalent to the claims are included.

Claims (11)

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:

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.

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

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 light-splitting crystal or the light-splitting element.

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

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.

Images