JP2017110935A - Ebsd detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an EBSD detector that has a smaller distortion of an EBSD pattern to be imaged and has a wider range of detecting an electron beam by EBSD, without changing the arrangement of an EBSD pattern detector, in a reflection EBSD method and a transmission EBSD method.SOLUTION: The EBSD detector includes: an electron beam source; a focusing lens; an object lens; a scanning coil; an EBSD pattern detector; and a sample holder. The detector analyzes the crystal orientation of a sample. The EBSD pattern detector can adjust an elevation angle to a sample in an imaging element for imaging an EBSD pattern.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an EBSD detection device, and more particularly to an EBSD detection device in which distortion of an EBSD pattern to be photographed is small and an electron beam detection range by EBSD is wide.

  In crystalline materials such as metals and ceramics, constituent atoms and molecules are arranged according to a certain pattern, and the characteristics of the crystalline material differ depending on the arrangement pattern (orientation information). Therefore, the orientation information of the crystalline material is important information for clarifying and controlling the characteristics of the material. The orientation information of the crystalline material can be analyzed by an electron back scattering diffraction (referred to as “EBSD” in this specification) method. The EBSD method is a method of analyzing crystal orientation based on an EBSD pattern (: Kikuchi line diffraction pattern) obtained by EBSD using a scanning electron microscope.

  FIG. 3 is a schematic diagram showing the measurement principle of the conventional reflective EBSD method. As shown in FIG. 3, a bulk sample 31 is placed in a scanning electron microscope, an electron beam (e−) is irradiated on the surface of the bulk sample 31, and a diffraction pattern of the electron beam reflected from the surface layer portion (reflective EBSD pattern) To get. A preferable angle between the surface 32 perpendicular to the optical axis of the electron beam (e−) incident on the bulk sample 31 and the bulk sample 31 is 60 ° to 70 °. The EBSD pattern is acquired by the fluorescent screen 33 of the EBSD pattern detector, and the azimuth information is mapped by scanning the electron beam on the sample surface. In this way, the crystal orientation in a predetermined local region of the crystalline material can be known.

  On the other hand, a transmission type EBSD method is known (see Non-Patent Document 1). FIG. 4 is a schematic diagram showing the measurement principle of the conventional transmission type EBSD method. As shown in FIG. 4, a thin film sample 41 is placed in a scanning electron microscope, an electron beam (e−) is irradiated from the objective lens 44 to the thin film sample 41, and a diffraction pattern (transmission EBSD pattern) by the transmitted electron beam is obtained. Acquired by the fluorescent screen 43 of the EBSD pattern detector, and the orientation information is mapped by scanning the electron beam on the sample. By using a thin film sample, the spread of the electron beam in the sample can be reduced, and the transmission type EBSD method can analyze a finer structure as compared with a normal reflection type EBSD method.

  As shown in FIG. 4, when the angle between the normal direction 45 of the thin film sample 41 and the optical axis of the electron beam is α, the surface 42 perpendicular to the optical axis of the electron beam incident on the thin film sample 41 and the thin film sample 41 The angle formed by is also α. The tilt angle α of the sample is preferably 0 ° to 40 °, particularly preferably 10 ° to 30 °, in that the resolution of the transmission EBSD pattern and the resolution of the orientation map image obtained by mapping the transmission EBSD pattern are good. . Further, the distance WD (working distance) from the lower end of the objective lens 44 to the measurement site of the thin film sample 41 is preferably 3 mm to 9 mm in terms of good resolution of the transmission EBSD pattern and the orientation map image, and 3 mm to 5 mm. Is particularly preferred.

R.R. Keller & R.H. Geys, “Transmission EBSD from 10 nm domains in a scanning electron microscope”, “Journal of Microscopy”, vol.245, 2012, pp.245-251

  The reflection type EBSD method and the transmission type EBSD method differ in the preferred arrangement of the sample, so the direction of the electron beam by EBSD generated from the measurement site of the sample is different. Therefore, when an EBSD pattern detector arranged for detecting a diffracted electron beam due to reflection is used to detect a diffracted electron beam due to transmission, the distortion of the transmitted EBSD pattern increases, and the detectable range of the EBSD pattern is increased. It tends to narrow. In addition, since the distortion is large, it is difficult to detect the band in the pattern, which tends to deteriorate the accuracy of indexing.

  The subject of this invention is providing the EBSD pattern detection apparatus which can respond to both a reflection type EBSD method and a transmission type EBSD method on preferable conditions, without changing arrangement | positioning of an EBSD pattern detector. In addition, the present invention has a small distortion of the EBSD pattern to be photographed in both the reflection type EBSD method and the transmission type EBSD method without changing the arrangement of the EBSD pattern detector, and the electron beam detection range by EBSD is wide. It is an object to provide an EBSD detection device.

  The EBSD detection device of the present invention includes an electron beam source, a focusing lens that focuses the electron beam from the electron beam source, an objective lens that forms an electron probe on the sample by further focusing the electron beam, and a sample on the sample. A scanning coil for scanning the electronic probe. In addition, an EBSD pattern detector that detects an EBSD pattern generated from the sample by an electron beam that is incident substantially vertically downward, and a sample holder that changes the tilt angle and arrangement of the sample with respect to the incident electron beam are provided. Analyze crystal orientation. In the EBSD detection device of the present invention, the elevation angle of the image sensor unit that captures the EBSD pattern with respect to the sample can be adjusted in the EBSD pattern detector.

  The image sensor unit has a hinge at the upper end, and the image sensor unit is pivotally connected to the EBSD pattern detector main body by the hinge, and the image sensor unit is a rod-like body that moves forward or backward in the longitudinal direction of the EBSD pattern detector. A mode in which the elevation angle with respect to the sample of the imaging element unit is adjusted by rotating is preferable. Further, the image sensor unit can be integrated with a camera having the image sensor unit as a component. The aspect which adjusts the elevation angle of this image pick-up element part to 20 degrees-50 degrees is preferable.

  The EBSD detection apparatus of the present invention can cope with both the reflection type EBSD method and the transmission type EBSD method under preferable conditions without changing the arrangement of the EBSD pattern detector. Moreover, an EBSD pattern with small distortion can be obtained by both the reflection type EBSD method and the transmission type EBSD method without changing the arrangement of the EBSD pattern detector, and the detection range of the diffracted electron beam can be widened.

It is a schematic diagram in the detection site | part of the EBSD detection apparatus of this invention, and the aspect from which the image pick-up element part 2 and the camera power supply part 13 are isolate | separated is shown. It is a schematic diagram in the detection site | part of the EBSD detection apparatus of this invention. It is a schematic diagram which shows the measurement principle of the conventional reflection type EBSD method. It is a schematic diagram which shows the measurement principle of the conventional transmission type EBSD method. It is a schematic diagram in the detection site | part of the EBSD detection apparatus of this invention, and the image pick-up element part 2 shows the aspect integrated with the camera 2a which uses the image pick-up element part 2 as a component.

  The EBSD detection apparatus of the present invention includes an electron beam source, a focusing lens that focuses the electron beam from the electron beam source, and an objective lens that forms an electron probe on the sample by further focusing the electron beam. Further, a scanning coil for scanning the electron probe on the sample, an EBSD pattern detector, and a sample holder are provided. The EBSD pattern detector detects an EBSD pattern generated from the sample by an electron beam incident substantially vertically downward. Moreover, the sample holder to be used can change the tilt angle and arrangement of the sample with respect to the incident electron beam, and the EBSD detection device can analyze the crystal orientation of the sample based on the EBSD pattern.

  FIG. 1 is a schematic diagram at a detection site of the EBSD detection device of the present invention, and shows an aspect in which the image sensor section 2 and the camera power supply section 13 are separated. FIG. 1A shows a mode in which the crystal orientation of the bulk sample 5 is detected by irradiating an electron beam from the objective lens 7 by the reflective EBSD method. A preferable inclination angle δ of the sample 5 in the reflection type EBSD method is 60 ° to 70 °. In the embodiment illustrated in FIG. 1A, the objective lens 7, the sample 5, and the image sensor unit 2 that captures the EBSD pattern are adjusted to have a preferable arrangement relationship when using the reflective EBSD method. ing. For this reason, a point (calibration point) perpendicular to the image sensor unit 2 from the measurement site of the sample 5 is located at the center of the image sensor unit 2, and the image sensor unit 2 captures the measurement site of the sample 5 from the front. Yes. Therefore, the diffracted electron beam 6 due to reflection can be sufficiently taken into the imaging element unit 2 and a reflected EBSD pattern with small distortion can be obtained.

  FIGS. 1B and 1C show an embodiment in which the crystal orientation of the crystalline thin film sample 8 is detected by irradiating an electron beam from the objective lens 7 by the transmission EBSD method. As shown in FIG. 1B, in the transmission EBSD method, the preferable inclination angle α of the sample 8 is 10 ° to 30 °, and the distance WD from the lower end of the objective lens 7 to the measurement site of the sample 8 is 3 mm to 5 mm is preferable. Therefore, if the tilt angle α and the WD are set to be preferable, the direction in which the diffracted electron beam is emitted by transmission is determined to some extent.

  Here, the arrangement of the EBSD pattern detector 1 and the imaging element unit 2 in FIG. 1B is the same as the preferred arrangement in the reflective EBSD method shown in FIG. For this reason, as shown in FIG. 1B, a part of the diffracted electron beam 3 due to transmission exceeds the imaging range of the imaging element unit 2. Further, a perpendicular foot (calibration point) dropped from the measurement site of the sample 8 to the image sensor unit 2 is in the vicinity of the upper edge of the image sensor unit 2, and the image sensor unit 2 obliquely transmits the diffracted electron beam 3 by transmission. It captures from. For this reason, the width of the band in the transmissive EBSD pattern is expanded at the lower part of the imaging element unit 2 as compared with the upper part, and distortion occurs in the transmissive EBSD pattern.

  Therefore, as shown in FIG. 1C, by tilting the image sensor unit 2 and providing an elevation angle β with respect to the sample 8, the diffracted electron beam 3 by transmission is sufficiently taken into the image sensor unit 2, and the diffracted electron beam by transmission is obtained. 3 can be widened. Moreover, as shown in FIG.1 (c), a calibration point exists in the center of the image pick-up element part 2, and the image pick-up element part 2 looks up the measurement site | part of the sample 8 in the front, and sees the diffraction electron beam 3 by transmission from the front. Therefore, the distortion of the transmission EBSD pattern is reduced.

  The EBSD detection apparatus of the present invention can adjust the elevation angle β of the image sensor section 2 in the EBSD pattern detector 1 with respect to the sample 8. For this reason, after analyzing the crystal orientation by the reflection type EBSD method, the crystal orientation can be analyzed by the transmission type EBSD method under preferable detection conditions without changing the arrangement of the EBSD pattern detector 1. In addition, an EBSD detection apparatus in which both the reflection type EBSD method and the transmission type EBSD method have a small distortion of an EBSD pattern to be photographed and a wide detection range of an electron beam by the EBSD without changing the arrangement of the EBSD pattern detector 1. Can be provided. Here, the elevation angle β of the image sensor unit 2 with respect to the sample 8 means an angle formed by the direction 9 and the horizontal plane 10 orthogonal to the image pickup surface 2b of the image sensor unit 2 as shown in FIG.

The preferred range of the elevation angle β when analyzing the crystal orientation by the transmission type EBSD method varies depending on the WD value, the inclination angle α of the sample 8, the arrangement of the imaging element unit 2, and the like. The detection range is preferably 20 ° or more, more preferably 25 ° or more, in that a pattern with a small distortion can be obtained. On the other hand, as the elevation angle β is increased, the electron beam (e ⁻ ) that passes through the sample is taken in more without being involved in the EBSD pattern, the detection result becomes brighter, and the pattern contrast tends to decrease. For this reason, the elevation angle β is preferably 50 ° or less, and more preferably 45 ° or less.

  As an adjustment method of the elevation angle β of the image sensor unit, as illustrated in FIG. 1C, a hinge 11 is provided at the upper end of the image sensor unit 2, and the image sensor unit 2 is connected to the EBSD pattern detector 1 by the hinge 11. It is connected to the main body of the machine so as to be rotatable. The EBSD pattern detector 1 includes a rod-shaped body 4 that moves forward or backward in the longitudinal direction. As shown in FIG. 1C, the image-capturing element section 2 is rotated by rotating the image-capturing element section 2 with the rod-shaped body 4. The elevation angle β with respect to the sample 8 can be adjusted. In the example shown in FIG. 1, the rod-shaped body 4 abuts on the lower part of the image sensor unit 2 and moves forward in the longitudinal direction, that is, moves rightward in FIG. β can be increased. Further, by moving the rod-like body 4 backward in the longitudinal direction, that is, by moving leftward in FIG. 1C, the elevation angle β can be reduced, and a preferable elevation angle β can be set by such a method.

  On the other hand, by using the EBSD detection device of the present invention, after analyzing the crystal orientation by the transmission type EBSD method, it is possible to analyze the crystal orientation by the reflection type EBSD method while maintaining the arrangement of the EBSD pattern detector as it is. it can. FIG. 2 is a schematic diagram at a detection site of the EBSD detection device of the present invention. FIG. 2A shows an embodiment in which the crystal orientation of the crystalline thin film sample 8 is detected by the transmission EBSD method. As shown in FIG. 2A, the preferred arrangement in the transmission EBSD method is that the inclination angle α of the sample 8 is 10 ° to 30 °, the WD is 3 mm to 5 mm, and the elevation angle of the image sensor 2. β is 20 ° to 50 °. In the transmission EBSD method, the arrangement relationship as shown in FIG. 2A makes it possible to widen the detection range of the diffracted electron beam 3 by transmission, and a transmission EBSD pattern with small distortion can be obtained.

  FIG. 2B and FIG. 2C show an embodiment in which the crystal orientation of the bulk sample 5 is detected by the reflective EBSD method. As shown in FIG. 2B, in the reflective EBSD method, the preferable inclination angle δ of the sample 5 is 60 ° to 70 °, and the direction in which the diffracted electron beam 6 is emitted by reflection depends on the arrangement of the sample 5. Determined to some extent. The arrangement of the EBSD pattern detector 1 and the imaging element unit 2 in FIG. 2B is the same as the preferred arrangement in the transmissive EBSD method in FIG. Therefore, in the mode shown in FIG. 2B, the calibration point is located below the image sensor unit 2, and the image sensor unit 2 captures the diffraction electron beam 6 due to reflection from an oblique direction. For this reason, compared with the lower part, the width | variety of the band in a reflective EBSD pattern expands in the upper part of the image pick-up element part 2, and a reflective EBSD pattern with a big distortion arises.

  Therefore, as shown in FIG. 2C, by setting the elevation angle β of the image sensor unit 2 to 0 °, the measurement site of the sample 5 is arranged in front of the image sensor unit 2, and the electron beam due to reflection Since 6 is caught from the front, the distortion of the pattern can be kept small. As described above, the EBSD detection device of the present invention can adjust the elevation angle β of the image sensor section 2 in the EBSD pattern detector 1. Therefore, after analyzing the crystal orientation by the transmission type EBSD method, the crystal orientation can be analyzed by the reflection type EBSD method under preferable detection conditions without changing the arrangement of the EBSD pattern detector 1.

  Further, it is possible to provide an EBSD detection device in which the distortion of the EBSD pattern is small and the detectable range of the diffracted electron beam is wide in both the reflection type EBSD method and the transmission type EBSD method without changing the arrangement of the EBSD pattern detector 1. be able to. In the example shown in FIG. 2 (c), the elevation angle β is adjusted to 0 °. However, the elevation angle β can be adjusted to a preferable value according to the measurement mode of the EBSD detection device. This can be easily performed by the hinge 11 and the rod-shaped body 4.

  FIG. 5 is a schematic diagram at a detection site of the EBSD detection device of the present invention, and shows an aspect in which the image sensor unit 2 is integrated with a camera 2a having the image sensor unit 2 as a constituent element. FIG. 5A shows an aspect in which the crystal orientation of the bulk sample 5 is analyzed by irradiating an electron beam from the objective lens 7 by the reflective EBSD method. As shown in FIG. 5A, in a preferred embodiment of the reflective EBSD method, the tilt angle δ of the sample 5 is 60 ° to 70 °. Further, in the example shown in FIG. 5A, the elevation angle of the imaging element unit 2 is 0 °. In this aspect, since the calibration point is located at the center of the image sensor section 2 in the EBSD pattern detector 1, it is possible to detect a reflected EBSD pattern having a wide detection range of the diffracted electron beam 6 by reflection and low distortion. it can.

  FIG. 5B shows an aspect in which the crystal orientation of the crystalline thin film sample 8 is analyzed by the transmission EBSD method. As shown in FIG.5 (b), the preferable measurement aspect in the transmission type EBSD method is that the inclination angle α of the sample 8 is 10 ° to 30 °, and the WD is 3 mm to 5 mm. In the example shown in FIG. 5B, the elevation angle β of the image pickup device portion 2 is adjusted to be 20 ° to 50 ° corresponding to the direction of the diffracted electron beam 3 due to transmission. Therefore, since the calibration point is at the center of the image sensor unit 2, the detection range of the diffracted electron beam 3 by transmission is wide, and the distortion of the transmission EBSD pattern can be reduced.

  Therefore, in the EBSD detection device illustrated in FIG. 5 as well, since the elevation angle β of the image pickup device unit 2 can be adjusted, it is preferable without changing the arrangement of the EBSD pattern detector 1 after analysis by the reflective EBSD method. Under the detection conditions, analysis can be performed by the transmission type EBSD method. Further, without changing the arrangement of the EBSD pattern detector, in both the reflective EBSD method and the transmissive EBSD method, a pattern with a wide detection range of electron beams by EBSD and a small distortion can be obtained.

  In the EBSD pattern detector 1 illustrated in FIG. 5, as shown in FIG. 5A, the image sensor unit 2 includes a hinge 11 at the upper end, and the hinge 11 is adjusted. As a result, the image pickup device unit 2 is rotatably connected to the main body of the EBSD pattern detector 1. The EBSD pattern detector 1 includes a rod-like body 4 that moves forward or backward in the longitudinal direction, and the imaging element portion 2 and the rod-like body 4 are rotatably connected by a hinge 11a. Therefore, as shown in FIG. 5B, the imaging element unit 2 is rotated by the rod-shaped body 4 to adjust the elevation angle β of the imaging element unit 2 with respect to the sample 8. That is, in the embodiment shown in FIG. 5A, by moving the rod-like body 4 forward in the longitudinal direction (moving rightward in FIG. 5A), as shown in FIG. The elevation angle β can be increased.

  In the aspect shown in FIG. 5, the image sensor unit 2 is integrated with a camera 2 a having the image sensor unit 2 as a component, and therefore the center of gravity of the camera 2 a body is not on the image sensor unit 2. However, even in such an embodiment, as shown in FIG. 5A, the elevation angle β of the imaging element unit 2 is set to a predetermined value by holding the imaging element unit 2 at a predetermined position by the rod-shaped body 4. Can be adjusted.

  It is possible to provide an EBSD pattern detection apparatus that can cope with both the reflection type EBSD method and the transmission type EBSD method under preferable conditions without changing the arrangement of the EBSD pattern detector.

DESCRIPTION OF SYMBOLS 1 EBSD pattern detector 2 Image pick-up element part 2a Camera 3 Diffraction electron beam by transmission 4 Rod-like body 5,8 Sample 6 Diffraction electron beam by reflection 7 Objective lens 11, 11a Hinge 13 Camera power supply part 31 Bulk sample 41 Thin film sample α, δ Sample tilt angle β Image sensor elevation angle WD Distance from the lower end of the objective lens to the measurement site of the sample

Claims (4)

An electron beam source;
A focusing lens for focusing the electron beam from the electron beam source;
An objective lens that forms an electron probe on the sample by further focusing the electron beam;
A scanning coil that scans the electron probe over the sample;
An EBSD pattern detector for detecting an electron back scattering diffraction (EBSD) pattern generated from the sample by an electron beam incident substantially vertically downward;
A sample holder for changing the tilt angle and arrangement of the sample with respect to the incident electron beam;
An EBSD detection device for analyzing the crystal orientation of a sample by an EBSD pattern,
In the EBSD pattern detector, an EBSD detection device capable of adjusting an elevation angle with respect to a sample of an image sensor unit that captures an EBSD pattern. The imaging device unit includes a hinge at the upper end,
The image pickup device portion is pivotably connected to the EBSD pattern detector main body by the hinge,
The EBSD detection apparatus according to claim 1, wherein the elevation angle of the imaging element unit with respect to the sample is adjusted by rotating the imaging element unit with a rod-like body that moves forward or backward in the longitudinal direction of the EBSD pattern detector.   The EBSD detection apparatus according to claim 1, wherein the image sensor unit is integrated with a camera having the image sensor unit as a constituent element.   The EBSD detection apparatus according to claim 1, wherein the image sensor unit adjusts an elevation angle to 20 degrees to 50 degrees.

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