JP2018022592A - Sample table and electron microscope with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sample table capable of controlling an inclination angle of a sample and an arrangement of a reflected electron detector.SOLUTION: A sample table 10 is arranged in an electron microscope that incidents an electron beam flux progressed on a virtual beam A into a surface of a sample 6. The sample table comprises: a main body part 1; a sample holding part 2 including a sample holding surface 2a; and a reflected electron detector 3 that includes a front surface 3a and a back surface 3b that are faced to the sample holding surface 2a in parallel and becomes a detection surface. The reflected electron detector 3 includes a penetration hole 3c in which the electron beam flux can be passed. The sample holding part 2 is swingably supported to the main body part 1 as a center of a point B on the virtual beam A. The reflected electron detector 3 can be retired and moved until a position where a region surrounded by an outer edge of the reflected electron detector 3 and a node C of the virtual beam A and the sample holding surface 2a are not overlapped and the detection surface is maintained in a state parallel to the sample holding surface 2a when viewing from a normal direction of the sample holding surface 2a. The electron beam flux is supported by the sample holding part 2 so as to be adjustably moved in a passible range of the penetration hole 3c.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sample stage and an electron microscope including the same.

  A scanning electron microscope (SEM) scans a sample surface by periodically irradiating an accelerated electron beam and irradiating it as an electron beam bundle, and a reflection generated from a local region of the irradiated sample. This is an apparatus for observing the surface morphology and composition distribution of materials by detecting electrons and / or secondary electrons and converting their electrical signals as material texture images.

  The electron beam extracted from the electron source in vacuum is immediately accelerated with different energy depending on the observation purpose from a low acceleration voltage of 1 kV or less to a high acceleration voltage of about 30 kV. The accelerated electron beam is focused to a nano-level microscopic diameter by a magnetic field coil such as a condenser lens and an objective lens to form an electron beam bundle, and simultaneously deflected by the deflection coil, thereby being focused on the sample surface. The line bundle is scanned. In addition, recently, a method in which an electric field coil is combined is also used for focusing an electron beam.

  In the conventional SEM, the main function is to observe the surface form of the sample by a secondary electron image and to examine the composition information by a reflected electron image due to the limitation of resolution. However, in recent years, it has become possible to focus an accelerated electron beam on a very small diameter of several nanometers while maintaining high luminance, so that a reflected electron image and a secondary electron image with very high resolution can be obtained. It has become.

  In order to obtain a reflected electron image and a secondary electron image, it is a reflected electron detector and a secondary electron detector that detect the reflected electrons and secondary electrons generated from the sample, respectively. Secondary electrons are generated when a voltage of several hundred volts is applied to the tip of the secondary electron detector to form a drawn potential field and are emitted from the sample surface in a different direction from the detector. Will also be drawn into the detector. For this reason, in obtaining a high-resolution secondary electron image, the placement of the secondary electron detector is rarely a major problem. On the other hand, reflected electrons with high energy cannot be bent and go straight and enter the detector, so that the appearance of the reflected electron image varies greatly depending on the arrangement of the reflected electron detector. Until now, various studies have been made on the method of arranging the backscattered electron detector with respect to the sample.

  For example, Patent Document 1 discloses a backscattered electron detector having a structure in which a disk-shaped electron beam detecting element having a hole in the center is attached to the top of a sample holder.

  Patent Document 2 discloses a scanning electron microscope in which two or four pairs of backscattered electron detectors are arranged along both sides of the lower magnetic pole piece of the objective lens along the sample tilt axis.

  Further, in Patent Document 3, when the observation surface of the sample is set to a predetermined inclination angle, the reflected electron detector is driven according to the inclination angle, and the detection surface of the reflected electron detector is relative to the observation surface of the sample. An electron microscope that is inclined to be parallel to each other is disclosed.

  By the way, as a feature of SEM, it is possible to observe a tissue in a local region with respect to a sample having a large size of several mm to several cm. Similarly, there is a transmission electron microscope (TEM) as means for observing a material structure using an electron beam. In TEM, an ultra-thin film sample is required in order to allow an electron beam to pass through the sample. As a result, the sample size is limited to a standard of 3 mm or less in diameter. Regarding observing resolution, TEM is higher, so TEM method is mainly used for observing crystal defects. On the other hand, the SEM method was used for observation of the surface texture shape, and both were used in a complementary manner.

  However, it is reported in Non-Patent Document 1 that, in a crystal grain satisfying several specific orientations, lattice defects near the sample surface can be observed with the same resolution as in TEM by utilizing a backscattered electron image in SEM. Yes.

JP 58-115383 A Japanese Patent Laid-Open No. 5-182626 JP 2007-200573 A

JEOL News Vol. 43, (2011) p. 7-12

  The mechanism of the observed dislocation contrast has not yet been elucidated, but it has been found that dislocation images are observed when the incident electron beam flux is irradiated under crystal orientation conditions that cause a channeling phenomenon to the sample. It was. Further, the dislocation structure changes in contrast very sensitively to a sample inclination of only a few degrees. In the structure observation of metal materials including iron and steel, the crystal grains in the observation field have various orientations. Therefore, in order to observe crystal defects such as dislocations by the SEM method, it is necessary to precisely tilt the observation surface of the sample with respect to the incident electron direction at an angle causing a channeling phenomenon with respect to individual crystal grains.

  Non-Patent Document 1 presents the possibility that lattice defects such as dislocations can be observed by SEM if a channeling phenomenon is intentionally caused from observation with a conventional general-purpose SEM. However, Non-Patent Document 1 only describes that the distance between the reflected electron detector and the sample surface should be shortened so that the reflected electrons reflected from the sample surface can be efficiently captured. It is not described that the observation surface needs to be inclined at an angle that causes a channeling phenomenon with respect to the incident electron direction.

  In Patent Document 1, no consideration is given to adjusting the tilt angle of the sample holder to which the backscattered electron detector is originally attached.

  In the method described in Patent Document 2, since there is only a tilt mechanism having only one direction as an axis, it is not possible to observe a change in contrast by tilting while observing a structure such as dislocation. In addition, due to spatial constraints, in order to detect backscattered electrons in any direction generated when tilting any sample, it is necessary to install countless backscattered electron detectors under the objective lens in various directions. Yes, this is not structurally realistic. Furthermore, when the sample stage is tilted by 10 ° or more, it is difficult to detect a signal with a backscattered electron detector installed in the vicinity of the objective lens.

  The device described in Patent Document 3 has only a tilt function that combines tilt and rotation about only one direction. In the rotation operation, only the image structure is rotated, and the dislocation contrast to be obtained corresponding to the crystallographic conditions does not change. Therefore, it is not suitable for observation of lattice defects such as dislocations in principle. Also, it takes a very long time to select the observation field and read the angle to tilt the backscattered electron detector. Work speed cannot be realized. Furthermore, since the SEM is a general-purpose apparatus that has already been placed in various research locations including on-site, it is desired that lattice defects can be observed in a general-purpose SEM instead of a special SEM.

  As described above, in the conventional technique, since the epoch-making knowledge that enables observation of individual dislocations by SEM method as in the TEM method has not been found, precise tilt control of the sample is required. It has never been done. Therefore, even if the sample stage described in Patent Documents 1 to 3 is used, it is impossible to search for channeling conditions for each crystal grain. Furthermore, when the tilt angle is increased, there is a problem that the incident electron beam does not reach the sample due to inappropriate arrangement of the backscattered electron detector.

  Further, in order to observe the dislocation contrast, it is desirable to grasp in advance crystal grain orientation information on the sample surface. In SEM, an electron back scatter diffraction (EBSD) device for simultaneously analyzing crystal orientation has been additionally installed. This makes it possible to obtain information on the crystal orientation of the sample in addition to information on the surface shape of the sample and information on the compositional differences of the material components such as precipitates and second phases. As a result, steel materials and aluminum materials can be obtained. In the field of metallic material parts such as SEM-EBSD, together with the conventional X-ray diffraction method, a new evaluation is applied to the control of crystal grain texture during the manufacturing process or the control of crystal plastic behavior during deformation of parts. It is actively used as a law.

  In order to measure the crystal orientation by EBSD, it is necessary to greatly tilt the sample to about 70 ° in the SEM. Therefore, even when the crystal orientation is measured by EBSD, there is a problem that the incident electron beam does not reach the sample if the backscattered electron detector is improperly arranged. As described above, in Non-Patent Document 1 and Patent Documents 1 to 3, the configuration of the sample stage suitable for observing the dislocation contrast is not studied.

  The present invention has excellent versatility and can be applied to existing electron microscopes, and it is possible to incline the sample so that conditions for observing crystal defect images can be obtained for individual crystal grains having various orientations. An object is to provide a sample stage capable of controlling the angle and the arrangement of backscattered electron detectors.

  The present invention has been made in order to solve the above-described problems, and provides the following sample stage and an electron microscope including the sample stage.

(1) A sample stage installed in an electron microscope for causing an electron beam bundle traveling on a virtual line extending in one direction to enter the surface of the sample,
A main body detachably attached to the electron microscope;
A sample holder having a sample holding surface for holding the sample;
A backscattered electron detector having a front surface and a back surface that is parallel to and opposed to the sample holding surface and serves as a detection surface;
The reflected electron detector has a hole penetrating from the front surface to the back surface and allowing the electron beam bundle to pass through,
The sample holding part is supported by the body part so as to be swingable around a point on the imaginary line as a center point,
The backscattered electron detector is
When viewed from the normal direction of the sample holding surface, the retreat movement is possible to retract to a position where the outer edge of the backscattered electron detector surrounds and the intersection of the virtual line and the sample holding surface does not overlap, and
The detection surface is supported by the sample holder so that the electron beam can be adjusted to move to a range where it can pass through the hole while maintaining the detection surface parallel to the sample holding surface.
Sample stage.

(2) The backscattered electron detector is supported by the sample holder so as to be retractable by rotating around an axis parallel to the normal direction of the sample holding surface.
The sample stage according to (1) above.

(3) The backscattered electron detector is supported by the sample holder so as to be retractable by rotating around an axis perpendicular to the normal direction of the sample holding surface.
The sample stage according to (1) above.

(4) The backscattered electron detector is detachably supported by the sample holder so as to be retractable.
The sample stage according to (1) above.

(5) The sample holding unit is rotatable around two axes that are parallel to the sample holding surface and intersect on the center point.
The sample stage according to any one of (1) to (4) above.

(6) The two axes are orthogonal to each other,
The sample stage according to (5) above.

(7) The center point is located between the sample holder and the backscattered electron detector.
The sample stage according to any one of (1) to (6) above.

(8) The main body part has three or more support parts that are height-adjustable and support the sample holding part.
The sample stage according to any one of (1) to (7) above.

(9) The apparatus further includes a mechanism capable of adjusting and moving the backscattered electron detector in a direction orthogonal to the detection surface.
The sample stage according to any one of (1) to (8) above.

(10) The apparatus further includes a mechanism capable of adjusting and moving the backscattered electron detector in two directions parallel to the detection surface and intersecting each other.
The sample stage according to any one of (1) to (9) above.

(11) The two directions are orthogonal to each other.
The sample stage according to (10) above.

(12) a first connector pin for receiving an electrical signal instructing swinging of the sample holder, a second connector pin for transmitting the electrical signal obtained by the backscattered electron detector, and the backscattered electron detection A third connector pin for receiving an electrical signal instructing movement of the device;
The sample stage according to any one of (1) to (11) above.

(13) The sample stage according to (12) above,
An installation section for installing the sample stage;
An electrical signal connector receiving port electrically connected to the first connector pin, the second connector pin, and the third connector pin;
A reflected electron propagation device that propagates a reflected electron signal obtained by the reflected electron detector;
A swing control device for controlling the swing of the sample holder;
An electron microscope comprising: a movement control device that controls movement of the reflected electron detector.

  By using the sample stage of the present invention, it is possible to freely select the incident electron beam orientation satisfying the optimum channeling phenomenon by installing it on a general-purpose SEM. Similarly, the dislocation structure can be observed. Conventionally, dislocation structure observation had to be performed by the TEM method, but high-resolution backscattered electron images can be obtained by the SEM method for crystal defects such as dislocations that affect the deformability and ductile fracture of the sample. it can.

It is the figure which showed typically an example of the microscope apparatus provided with the sample stand which concerns on this invention. It is the figure which showed typically one Embodiment in the state holding the sample of the sample stand which concerns on this invention. It is the figure which showed typically one Embodiment at the time of the crystal orientation measurement by EBSD of the sample stand which concerns on this invention. It is the figure which showed typically other embodiment at the time of the crystal orientation measurement by EBSD of the sample stand which concerns on this invention. It is a figure for demonstrating the retraction | saving movement of the backscattered electron detector 3. FIG. It is the figure which showed typically other embodiment at the time of the crystal orientation measurement by EBSD of the sample stand which concerns on this invention.

  An embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram schematically showing an example of a microscope apparatus provided with a sample stage according to the present invention. In FIG. 1, the SEM is described as an example. However, the sample stage according to the present invention is not limited to the SEM, and the sample surface may be irradiated with an electron beam bundle such as an electron probe micro analyzer (EPMA). It can be installed in a possible device.

  The SEM includes a SEM main body 100 and an external drive device and control device. The SEM main body 100 extracts an electron beam from an electron source and emits it while accelerating it, an electron gun control device 25 that controls the acceleration voltage of the electron beam, and a condenser lens 30 that focuses the accelerated electron beam bundle. A focusing lens system control device 35 for controlling the opening angle thereof, an objective lens 40 for converging the focused electron beam bundle to a minute region on the sample, a pole piece 50 including the same, and an objective lens system control device 45 And a deflection coil 60 for scanning the electron beam bundle on the sample, and a deflection coil controller 65. The electron beam bundle converged by the objective lens 40 is incident on a virtual line A extending in one direction shown in FIG. 1 with respect to the surface of the sample. Although the actual electron beam bundle has a very small width, in the present invention, the virtual line A is assumed to be the same as the direction in which the line connecting the center of the deflection coil and the center of the objective lens extends.

  Secondary electrons generated when the sample surface is irradiated with the electron beam bundle are detected by being drawn into the secondary electron detector 70, and are synchronized with the scanning of the electron beam via the secondary electron signal propagation device 75. Thus, a secondary electron image as an observation image is obtained by the display device 80.

  Further, an electron backscatter diffraction (EBSD) detector 90 is attached to the SEM. In the configuration shown in FIG. 1, the signal obtained by the electron backscatter diffraction detector 90 is sent to the sample crystal orientation display device 94 via the electron backscatter diffraction signal propagation device 92.

  The sample stage 10 is installed on the installation unit 15 in the electron microscope. FIG. 2 is a diagram schematically showing an embodiment of the sample stage 10 in a state where the sample 6 is held. As shown in FIG. 2, the sample stage 10 includes a main body 1, a sample holder 2, and a backscattered electron detector 3. With the above configuration, the reflected electron image can be observed by irradiating the surface of the sample 6 with the electron beam bundle traveling on the virtual line A and detecting the reflected electrons with the reflected electron detector 3. . Each component will be described.

1. Main Body Part The main body part 1 is a part that is detachably attached to the installation part 15 of the electron microscope. About the method of attaching the main-body part 1 to the installation part 15, it is the same as that of the conventional method, and a special process is not accompanied. Therefore, the sample stage according to the present invention can be attached to a general-purpose SEM. The position of the sample stage 10 can be changed in the SEM by driving the installation unit 15 by the driving device 17.

2. Sample Holding Unit The sample holding unit 2 has a sample holding surface 2 a that holds the sample 6. The sample 6 can be bonded to the sample holding surface 2a using a conductive carbon tape or the like. When observing lattice defects typified by dislocations on the sample surface, it is desirable that the sample surface be smoothed by electrolytic polishing or the like. The shape of the sample holder 2 is not particularly limited, and when viewed from the normal direction of the sample holding surface 2a, the shape may be a quadrangle, a polygon, a circle, an ellipse, or the like. Good.

  In examining the sample composition in the information of the reflected electron image irradiated on the sample, it is only necessary to collect the reflected electron beam reflected from the sample. However, the lattice defects of the sample such as dislocations and stacking faults are information depending on the Bragg diffraction reflection, and it is very important to set conditions for the incident electron beam to enter the sample at what angle. Therefore, it is necessary to freely adjust the inclination angle of the sample holder 2 with respect to the virtual line A. Therefore, the sample holder 2 is configured to be supported by the main body 1 so as to be swingable around the point B on the virtual line A. At this time, as shown in FIG. 2B, the sample holding unit 2 is configured to be rotatable around two axes that are parallel to the sample holding surface 2a and are orthogonal on the center point B. It is desirable. In FIG. 2, the two axes are orthogonal to each other, but they need only intersect.

  The center point B may be on the virtual line A, but is preferably located between the sample holding surface and the detection surface. Further, as shown in FIG. 2, the center point B is adjusted so as to coincide with the sample surface, and further, the above-mentioned two axes are set so as to coincide with the X direction and the Y direction of the reflected electron image appearing on the monitor. For example, it is possible to realize a mechanism for tilting the sample freely around the X and Y directions on the monitor while observing the tissue image. Note that the center point B does not have to be strictly on the imaginary line A, and deviation is allowed to the extent that the field of view does not change significantly when the sample holding surface is swung.

  The above-described tilting mechanism of the sample holder 2 can be realized, for example, by supporting the sample holder 2 on two orthogonal arcs provided in the main body 1 so as to be independently movable. . In addition, as shown in FIG. 2, the tilting mechanism can also be realized by adopting a configuration in which the main body 1 is adjustable in height and has three or more support parts 1 a that support the sample holding part 2. Can do. This is because the sample holder 2 can swing around the center point B by relatively changing the vertical position of the support 1a. As the support portion 1a, for example, a minute displacement jig using a piezoelectric element or the like can be used.

  As will be described later, when measuring the crystal orientation by EBSD, it is necessary to incline the sample up to about 70 ° in the SEM, but it is usually difficult to incline the sample stage in the SEM by 70 °. However, by using the above tilt mechanism, for example, by setting the tilt angle of the sample holder 2 to about 20 °, the tilt angle of the sample table itself can be reduced to about 50 °.

  The inclination angle of the sample holder 2 with respect to the imaginary line A can be operated from the outside by an electrical signal. For example, the first connector pin 5a is provided in the main body 1 of the sample stage 10, and is electrically connected to the swing control device 84 provided in the SEM via the electric signal connector receiving port 82 of the SEM main body 100, and the electric signal is sampled. By transmitting to the table 10, the swing of the sample holder can be controlled. Note that electrical signals can be transmitted not only by direct connection but also by non-contact communication such as infrared or wireless.

3. Backscattered electron detector The backscattered electron detector 3 has a front surface 3a and a back surface 3b. The back surface 3b is a portion to be a backscattered electron detection surface, and is parallel to and opposed to the sample holding surface 2a. The sample holding surface 2a and the back surface 3b do not need to be strictly parallel, but may be substantially parallel. FIG. 2C is a perspective view for explaining the configuration of only the backscattered electron detector 3 and moving mechanisms 2d and 2e and a rotating mechanism 2f described later. In the configuration shown in FIG. 2, the backscattered electron detector 3 has a quadrangular shape when viewed from the normal direction of the surface 3a. However, the shape is not limited to this, and may be, for example, a polygon, a circle, an ellipse, or the like. There may be.

  The backscattered electron detector 3 has a hole 3c that penetrates from the front surface 3a to the back surface 3b and through which the electron beam bundle can pass. The hole 3c serves not only to pass the electron beam bundle irradiated to the sample surface but also to play back the reflected electrons that are noise factors scattered by Rutherford from the sample. The shape of the hole is not particularly limited and may be rectangular, for example, but is preferably circular as shown in FIG.

  Further, there is no particular limitation on the size of the hole. Most of Rutherford backscattering, which is a noise factor in the reflected electron image when observing a crystal lattice defect image, is emitted in a direction opposite to the imaginary line A. Therefore, the hole diameter d is 0 in consideration of the electron beam bundle diameter. It is desirable to set it to 0.1 mm or more. On the other hand, if the diameter d of the hole becomes too large, the area of the detection surface of the reflected electrons becomes small. Therefore, d is preferably 2 mm or less. Further, the diameter d of the hole is more preferably 1 mm or less.

  As described above, the direction of the incident electron beam on the sample is important for observing crystal lattice defects. And in order to make full use of this technique, it is desirable to know the orientation information of the crystal grains on the sample surface in advance. That is, the sample stage 10 is used not only for observation of the reflected electron image but also for measurement of crystal orientation by EBSD. When measuring the crystal orientation by EBSD, it is necessary to greatly tilt the sample to about 70 ° in the SEM and to project the diffraction pattern onto the detection surface of the electron backscatter diffraction detector 90, as shown in FIG. Moreover, the backscattered electron detector 3 can be an obstacle. For this reason, the backscattered electron detector 3 needs to be supported by the sample holder 2 so as to be retractable.

  With reference to FIG. 3B, the retractable movement means that the region surrounded by the outer edge of the backscattered electron detector 3, the virtual line A, and the sample holding surface 2a when viewed from the normal direction of the sample holding surface 2a. This means that the backscattered electron detector 3 can be retracted to a position where it does not overlap with the intersection C. The reflected electron detector 3 is retracted to a position where the region surrounded by the outer edge of the reflected electron detector 3 and the sample 6 placed on the sample holding surface 2a do not overlap when viewed from the normal direction of the sample holding surface 2a. Preferably it is possible.

  Also, as shown in FIG. 4, in order to project the diffraction pattern more clearly on the detection surface of the electron backscatter diffraction detector 90, the reflected electron detector is viewed from the normal direction of the sample holding surface 2a. 3 and the intersection B between the virtual line A and the surface (observation surface) of the sample 6 do not overlap, and the entire detection surface of the electron backscatter detector 90 can be seen from the point B without being blocked. The backscattered electron detector 3 is preferably retractable up to the position. That is, it is preferable that the backscattered electron detector 3 can be retracted from a region surrounded by a substantially conical shape having the point B as the apex and the detection surface of the electron backscattering detector 90 as the bottom surface.

  5A and 5B are views of the sample stage 10 viewed from the normal direction of the sample holding surface 2a. For example, as shown in FIG. 5 (a), the backscattered electron detector 3 rotates 90 ° clockwise around an axis parallel to the normal direction of the sample holding surface 2a around the rotation mechanism 2f. Thus, the entire detection surface of the electron backscatter detector 90 can be retracted to a position where it can be seen without being blocked.

  In the configuration shown in FIG. 5A, the rotation mechanism 2f is provided at the corner of the sample holding surface 2a, but the position where the rotation mechanism 2f is provided is not particularly limited. From the viewpoint of retracting the reflected electron detector 3 from the point B to a position where the entire detection surface of the electron backscatter detector 90 can be seen without being blocked, the rotating mechanism 2f is viewed from the normal direction of the sample holding surface 2a. In some cases, it is preferable to provide the sample holding surface 2a in a region along a side that does not intersect the virtual line A among the sides of the sample holding surface 2a. For example, as shown in FIG. 5B, it may be provided at the center of the side that does not intersect the virtual line A. When the above configuration is adopted, it is possible to reduce a space required for the retraction movement of the backscattered electron detector 3.

  3 to 5 includes a rotation mechanism 2f, and the backscattered electron detector 3 can be retreated by rotating around an axis parallel to the normal direction of the sample holding surface 2a. The configuration in which the backscattered electron detector 3 is supported by the sample holder 2 so as to be retractable is not limited to the above configuration. For example, as shown in FIG. 6A, the sample has a rotating mechanism 2f ′, and the backscattered electron detector 3 rotates around an axis perpendicular to the normal direction of the sample holding surface 2a so as to be retractable. As shown in FIG. 6B, the holding unit 2 may have a detachable mechanism 2g, and the backscattered electron detector 3 is detachably supported so as to be retractable. May be.

  Furthermore, the backscattered electron detector 3 is supported by the sample holder 2 so as to be adjustable. With reference to FIG. 2, adjustment movement is possible to the extent that the electron beam bundle can pass through the hole 3c while maintaining the detection surface of the reflected electron detector 3 substantially parallel to the sample holding surface 2a. This means that the position of the backscattered electron detector 3 can be adjusted. Specifically, it is desirable to provide a mechanism capable of moving the backscattered electron detector 3 in a direction perpendicular to the detection surface and in a parallel direction.

  The distance between the sample holder 2 and the backscattered electron detector 3 may be appropriately adjusted according to the thickness of the sample 6 or the like. The reflected electrons reflected from the sample surface at a wide angle may not reach the detection surface of the reflected electron detector 2 if the distance L is large. Therefore, in order to adjust the lattice defect contrast such as the optimum dislocation, it is desirable to include a mechanism 2b that can move the backscattered electron detector 3 in a direction orthogonal to the detection surface. The distance L is preferably 10 mm or less, but is not necessarily limited and depends on the observation conditions.

  A piezoelectric element can be used as a method for controlling a minute movement amount in a direction orthogonal to the detection surface. In the embodiment shown in FIG. 2, the sample holder 2 can adjust the height in a direction orthogonal to the detection surface, and has a single column for holding the backscattered electron detector 3. However, in order to adjust the height with high accuracy, the backscattered electron detector 3 may be held by a plurality of columns. However, in this configuration, it is difficult to provide the rotation mechanism 2f for the retreat movement described above, and therefore it is preferable that each of the plurality of support columns has an attachment / detachment mechanism 2g.

  As shown in FIG. 1, it is desirable that the amount of reflected electrons incident on the reflected electron detector 3 is converted into an electric signal of current and voltage fluctuations and sent to the reflected electron propagation device 88. Therefore, it is desirable to provide the second connector pin 5 b on the sample holder 2 of the sample stage 10 for transmitting an electric signal to the reflected electron propagation device 88 through the electric signal connector receiving port 82 of the SEM main body 100. The position and structure of this pin may be appropriately changed depending on the configuration of a general-purpose SEM body. Note that electrical signals can be transmitted not only by direct connection but also by non-contact communication such as infrared or wireless.

  Here, although depending on the size of the hole, when the inclination angle of the sample holder 2 is increased, the position of the hole 3c of the reflected electron detector 3 inclined together with the sample holder 2 is shifted from the imaginary line A. The electron beam bundle collides with the surface 3 a of the reflected electron detector 3 and does not reach the surface of the sample 6. Therefore, a mechanism 2c that moves the backscattered electron detector 3 to a position where the electron beam bundle can pass through the hole 3c is necessary. At this time, it is not preferable that the height in the direction orthogonal to the detection surface, that is, the distance L, changes the measurement conditions. Therefore, as shown in FIG. 2C, the backscattered electron detector 3 can be moved in two directions that are parallel to the detection surface and orthogonal to each other while the height in the direction orthogonal to the detection surface is fixed. It is desirable to include the mechanisms 2d and 2e that can be used. In FIG. 2C, the two directions are orthogonal to each other, but it is only necessary to intersect.

  The mechanism for moving the backscattered electron detector 3 in two directions that are parallel to the detection surface and orthogonal to each other can be miniaturized by applying a piezoelectric element, for example. In addition, as shown in FIG. 2C, if the above two directions are set so as to coincide with the X direction and the Y direction of the reflected electron image appearing on the monitor, the tissue image is observed on the monitor. A mechanism for freely moving in the X direction and the Y direction can be realized.

  The mechanism 2b that moves in the direction perpendicular to the detection surface of the reflected electron detector 3, the mechanisms 2d and 2e that move in two directions that are parallel and orthogonal to each other, and the retracted movement of the reflected electron detector 3 The rotating mechanism 2f or 2f ′ to be performed can be operated from the outside by an electrical signal. For example, the third connector pin 5c is provided in the sample holder 2 of the sample stage 10, and is electrically connected to the movement control device 86 provided in the SEM via the electric signal connector receiving port 82 of the SEM body 100, and the electric signal is transmitted. By transmitting to the sample stage 10, the movement of the backscattered electron detector 3 can be controlled. Note that electrical signals can be transmitted not only by direct connection but also by non-contact communication such as infrared or wireless. Further, the moving mechanism 2c in the direction parallel to the detection surface of the reflected electron detector 3 may be a mechanism that can be controlled so as to minimize the deviation in accordance with the positional relationship between the electron beam bundle and the hole.

1. Main body 1a. Support part 2. Sample holder 2a. Sample holding surface 2b. Orthogonal direction moving mechanism 2c. Parallel movement mechanism 2d. X direction moving mechanism 2e. Y-direction moving mechanism 2f, 2f ′. Rotating mechanism 2g. 2. Detachable mechanism Backscattered electron detector 3a. Surface 3b. Back side 3c. Hole 5a. First connector pin 5b. Second connector pin 5c. Third connector pin 6. Sample 10. Sample stage 15. Installation unit 17. Drive device 20. Electron gun 25. Electron gun control device 30. Condenser lens 35. Focusing lens system controller 40. Objective lens 45. Objective lens system controller 50. Pole piece 60. Deflection coil 65. Deflection coil controller 70. Secondary electron detector 75. Secondary electron signal propagation device 80. Display device 82. Electrical signal connector receiving port 84. Swing control device 86. Movement controller 88. Backscattered electron propagation device 90. Electron backscatter diffraction detector 92. Electron backscatter diffraction signal propagation device 94. Sample crystal orientation display device 100. SEM body

Claims (13)

A sample stage installed in an electron microscope that causes an electron beam bundle traveling on a virtual line extending in one direction to enter the surface of the sample,
A main body detachably attached to the electron microscope;
A sample holder having a sample holding surface for holding the sample;
A backscattered electron detector having a front surface and a back surface that is parallel to and opposed to the sample holding surface and serves as a detection surface;
The reflected electron detector has a hole penetrating from the front surface to the back surface and allowing the electron beam bundle to pass through,
The sample holding part is supported by the body part so as to be swingable around a point on the imaginary line as a center point,
The backscattered electron detector is
When viewed from the normal direction of the sample holding surface, the retreat movement is possible to retract to a position where the outer edge of the backscattered electron detector surrounds and the intersection of the virtual line and the sample holding surface does not overlap, and
The detection surface is supported by the sample holder so that the electron beam can be adjusted to move to a range where it can pass through the hole while maintaining the detection surface parallel to the sample holding surface.
Sample stage. The backscattered electron detector is supported by the sample holder so as to be retractable by rotating around an axis parallel to the normal direction of the sample holding surface.
The sample stage according to claim 1. The backscattered electron detector is supported by the sample holder so that it can be retracted by rotating around an axis perpendicular to the normal direction of the sample holding surface.
The sample stage according to claim 1. The backscattered electron detector is detachably supported by the sample holder so as to be retractable.
The sample stage according to claim 1. The sample holder is rotatable about two axes parallel to the sample holding surface and intersecting on the center point;
The sample stage according to any one of claims 1 to 4. The two axes are orthogonal,
The sample stage according to claim 5. The center point is located between the sample holder and the backscattered electron detector;
The sample stage according to any one of claims 1 to 6. The main body part has three or more support parts that are height-adjustable and support the sample holding part,
The sample stage according to any one of claims 1 to 7. A mechanism capable of adjusting and moving the backscattered electron detector in a direction perpendicular to the detection surface;
The sample stage according to any one of claims 1 to 8. A mechanism capable of adjusting and moving the backscattered electron detector in two directions parallel to the detection surface and intersecting each other;
The sample stage according to any one of claims 1 to 9. The two directions are orthogonal,
The sample stage according to claim 10. A first connector pin for receiving an electrical signal instructing swinging of the sample holder, a second connector pin for transmitting an electrical signal obtained by the backscattered electron detector, and movement of the backscattered electron detector A third connector pin for receiving an electrical signal indicating
The sample stage according to any one of claims 1 to 11. The sample stage according to claim 12,
An installation section for installing the sample stage;
An electrical signal connector receiving port electrically connected to the first connector pin, the second connector pin, and the third connector pin;
A reflected electron propagation device that propagates a reflected electron signal obtained by the reflected electron detector;
A swing control device for controlling the swing of the sample holder;
An electron microscope comprising: a movement control device that controls movement of the reflected electron detector.

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