JPH11233057A - Scanning electron microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To directly observe a part of an enlarged image of a large sample by pacing an extremely large sample such as a mechanical part on a sample stage and also placing a mirror cylinder on a transfer mechanism, by evacuating the whole, by positioning the mirror cylinder at any place of the sample in any direction and by scanning it by irradiating a beam, in a scanning electron microscope to display an enlarged image by detecting a charged particle emitted or absorbed by directly scanning a beam on the large sample. SOLUTION: This electron microscope is equipped with a sample stage 1 to transfer a large sample placed on it, a mirror cylinder 3 which emits a beam with a reduced diameter and also scans the emitted the emitted beam, a transfer mechanism 4 to position the beam emitted from the mirror cylinder at any placed of a sample 2 on the stage from any direction, a detector to detect a charged particle emitted or absorbed when the sample is scanned by the beam, and a chamber which contains the sample stage, the mirror cylinder, the transfer mechanism and the detector and is evacuated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning electron microscope for directly scanning a large sample with a beam to detect emitted or absorbed charged particles and display an enlarged image.

[0002]

2. Description of the Related Art Conventionally, a scanning electron microscope has been used to enlarge a small one so that a sample is limited to a relatively small one. For example, having a structure as shown in FIG. 3, electrons emitted from the electron gun are focused by a focusing lens,
The electron beam is finely focused on the sample by the objective lens, scanned in the X and Y directions by the deflection coil, the secondary electrons generated at that time are detected, and the secondary electron density image (secondary image) is displayed on the screen. (Electronic image) was displayed, and a small portion of the sample was observed under magnification.

[0003]

As described above, in the conventional structure shown in FIG. 3, a large sample portion cannot be observed in an enlarged manner because the sample is placed in the sample chamber. Only a diameter size can be observed, and even in this case, the sample chamber is particularly large so that a wafer can be inserted.

However, a large mechanical component such as a gear of a car transmission cannot be put into the sample chamber of FIG. 3 as it is, and cannot be observed. There is no other way but to observe the object, and this method has a problem that the original mechanical parts are destroyed.

[0005] The present invention solves these problems,
An extremely large sample such as a mechanical component is placed on the sample stage, and the lens barrel is placed on the moving mechanism to evacuate the entire body.The lens barrel is positioned at an arbitrary position on the sample in an arbitrary direction and irradiated with a beam to scan. It is intended to enable a magnified image of a part of a large sample to be directly observed.

[0006]

Means for solving the problem will be described with reference to FIG. In FIG. 1, a sample stage 1
Is for placing a large sample 2 and moving it in the X, Y, and Z directions.

The sample 2 is a large sample which is directly irradiated with a beam and scanned to display an enlarged image. The lens barrel 3 irradiates the sample 2 with a narrowed beam and scans the beam.

The moving mechanism 4 moves the lens barrel 3 so as to irradiate a beam emitted from the lens barrel 3 to an arbitrary place of the sample 2 from an arbitrary direction. The large bell jar 5 is a container for storing the sample table 1, the sample 2, the lens barrel 3, the moving mechanism 4, and the like in a vacuum.

Next, the operation will be described. A large sample 2 is fixed on a sample table 1 and a large bell jar 5 is placed thereon to evacuate the whole. After evacuation, the moving mechanism 4 is controlled so that the beam emitted from the lens barrel 3 is radiated from a desired direction to a desired position of the sample 2 and scanned. Next, by controlling the current supplied to the deflection coil in the lens barrel 3, the beam is irradiated on the sample 2 at an arbitrary size, and the current absorbed by the sample 2 at that time is detected by a detector (not shown). Alternatively, the discharged charged particles are detected by a detector (not shown), and an enlarged image (for example, a secondary electron image) is displayed on a display device (not shown) based on the detected signal and the signal supplied to the deflection coil. I do. In order to display different locations on the sample 2 on the display device, a moving mechanism (X, Y, Z) (not shown) of the sample table 2 is controlled to display an arbitrary location of the sample 2 on the display device. In the case of a minute movement, a current is supplied to the deflection coil in the lens barrel 3 to display a minute desired image of the position of the sample 2.

At this time, the moving mechanism 4 is fixed to the large bell jar 5, and when the large bell jar 5 is lifted, the lens barrel 3 is lifted together so that the large sample 2 can be easily attached to and detached from the sample table 1. I have.

Instead of removing the large bell jar 5 and exchanging the sample 2 shown in FIG. 1, the sample table 1 may be detached (for example, moved downward) and the sample 2 may be exchanged.

Further, a spacer 11 is provided so as to change the height or size of the chamber 2 according to the height of the sample 2 stored in the chamber (large bell jar 5).

Therefore, an extremely large sample 2 such as a mechanical component is placed on the sample table 1 and the lens barrel 3 is placed on the moving mechanism 4 to evacuate the whole, and the lens barrel 3 is placed at an arbitrary position on the sample 2 in an arbitrary direction. By irradiating and scanning with a beam at a position, an enlarged image of the large sample 2 can be directly observed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments and operations of the present invention will be described in detail with reference to FIGS.

FIG. 1 shows a structural diagram of an embodiment of the present invention.
FIG. 1A shows an overall structure diagram. In FIG. 1A, a sample table 1 is for mounting a large sample 2 and rotating the sample in an X direction, a Y direction, and a Z direction, and further, if necessary.

The sample 2 is a large sample which is directly irradiated with a beam and scanned to display an enlarged image. The lens barrel 3 is used to irradiate the sample 2 with a narrowed beam and scan the beam. In the case of an electron beam, the lens barrel 3 includes an electron gun, a focusing lens, an objective lens, a deflection coil, and the like. . In addition to the electron beam, an ion beam which is a charged particle may be used.

The moving mechanism 4 moves the lens barrel 3 so as to irradiate a beam emitted from the lens barrel 3 to an arbitrary place of the sample 2 from an arbitrary direction (to be described later with reference to FIG. 2). Do).

The large bell jar 5 is a container for accommodating the sample table 1, the sample 2, the lens barrel 3, the moving mechanism 4, etc., and evacuating and maintaining the vacuum. The gantry 6 is a gantry on which the sample table 1, the lens barrel 3, the large bell jar 5, and the like are mounted.

FIG. 1B shows an example in which the spacer 11 is inserted between the large bell jar 5 and the gantry 6. In FIG. 1B, the spacer 11 has the same inner diameter when the dimensions such as the height and the size of the sample 2 in FIG. 1A become too large to be accommodated in the large bell jar 5. It is extended in the height direction. In addition, large bell jar 5
In the case of a size that cannot be accommodated in the inside, the spacer 11 having a diameter that can be accommodated is attached so as to remove the gutter.
In the case of the long rod-shaped sample 2, a cylinder capable of storing the long rod-shaped sample 2 is attached so as to penetrate the spacer 11 of FIG. The long sample 2 is stored therein without cutting. Similarly, in the case of flattening (flattening in the shape of a plate) or the like, the sample 2 is put into the inside (in vacuum) of the spacer 11 having a shape capable of accommodating them.

FIG. 2 shows a structural diagram of an embodiment of the present invention. In FIG. 2, the sample stage 1 has X
The sample 2 is moved in the directions, the Y direction, and the Z direction, and has a mechanism for controlling a control device (not shown) to an arbitrary position (X, Y, Z).

The sample 2 is a large mechanical component, for example, a gear of a vehicle transmission. The lens barrel 3 irradiates and scans the beam by narrowing the beam narrowly, and includes an electron gun, a focusing lens, an objective lens, a deflection coil, and the like. Here, the entire lens barrel 3 is fixed to the inclined arm 42 by the holding portion 41.

The moving mechanism 4 includes a holding section 41, an inclined arm 4
2. It comprises a rotation / tilt mechanism 43 and the like, and irradiates a beam emitted from the lens barrel 3 to an arbitrary place of the sample 2 from an arbitrary direction.

The holding section 41 holds and fixes the lens barrel 3. The tilt arm 42 is an arm that holds the lens barrel 3 with the holding unit 41 and tilts the lens barrel 3.

The rotation / tilt mechanism 43 tilts the tilt arm 42 to tilt the lens barrel 3 or rotates the tilt arm 42 while tilting it.
This is for radiating a beam radiated from an arbitrary direction on an arbitrary place of the sample 2 from the arbitrary direction.

The vacuum chamber 51 is a container for exchanging the sample 2 by being lifted upward by the lifting device 52, and for lowering the gas to be evacuated to vacuum. The lifting device 52 is a lifting device such as a crane, which lifts the vacuum tank 51 upward to exchange the sample 2 or lowers the vacuum tank 51 to evacuate and evacuate.

Next, the operation will be described. (1) The lifting device 52 lifts the vacuum chamber 51 and the moving mechanism 4 fixed to the vacuum chamber 51 upward, and positions the vacuum mechanism 51 above the sample 2. Further, the sample 2 is moved in the lateral direction to a position distant from directly above the sample 2.

(2) The sample 2 is removed, and other large mechanical parts are fixed to the sample table 1. At this time, in the case of a large mechanical component that cannot be held manually, the lifting device 5
The sample 2 is lifted by using 2 and transported to the position of the sample stage 1 shown in the figure to be fixed.

(3) The vacuum chamber 51 and the moving mechanism 4 are lowered using the lifting device 52 and fixed at the illustrated position. (4) The interior of the vacuum chamber 51 is evacuated to a vacuum.

(5) The beam emitted from the lens barrel 3 held by the holding unit 41 by controlling the rotation / tilt mechanism 53 as the moving mechanism 4 is emitted to a desired position of the sample 2 from a desired direction. Adjust as follows. At this time, the sample stage 1 is set in the X direction,
The position to be observed is controlled in the Y and Z directions so as to substantially coincide with a predetermined reference point (the center point which is the center of rotation and tilt when the lens barrel 3 is lined and tilted by the rotation and tilt mechanism 43).

(6) The power of the electron gun of the lens barrel 3 is turned on, and a beam is emitted from the lens barrel 3 to start scanning a desired position of the sample 2 from a desired direction. When this scanning is started, an image enlarged on a display device based on the signal absorbed by the sample 2 or the signal detected and emitted (for example,
An absorption electron image, a secondary electron image, etc.).

(7) On the image displayed in (6), the sample 2 is moved or a current is applied to the deflection coil so as to be finely observed so as to further focus, contrast, and further observe a desired place. The position of the sample 2 is moved and adjusted so that a desired image is displayed on the display device.

As described above, it is possible to exchange the sample 2 and display an enlarged image of a desired place of the sample 2 viewed from a desired direction. In particular, in the case of the illustrated gear,
It is possible to freely display an enlarged image viewed from an arbitrary three-dimensional direction, such as an enlarged image viewed from directly above the gear and a further enlarged image viewed from a lateral direction. In addition, an enlarged image (for example, an enlarged image of several times to several hundred thousand times) obtained by directly observing a non-destructive and extremely large sample 2, for example, a large sample of several tens of cm to several meters from a three-dimensional arbitrary direction. It is now possible to freely and non-destructively display. At the same time as the display, energy analysis of charged particles and the like emitted from the sample 2 can be performed, and element analysis of each part in the magnified image directly observed can also be performed.

In FIG. 2, the vacuum tank 51 is lifted up by the lifting device 52 to exchange the sample 2. However, the present invention is not limited to this. Alternatively, the sample table 1 may be moved downward by the moving mechanism 4 to exchange the sample 2.

[0034]

As described above, according to the present invention,
An extremely large sample 2 such as a mechanical component is placed on the sample stage 1 and the lens barrel 3 is placed on the moving mechanism 4 to evacuate the whole. The lens barrel 3 is positioned at an arbitrary position on the sample 2 in an arbitrary direction to emit a beam. Since the configuration of irradiating and scanning is employed, an enlarged image of the large sample 2 can be directly observed. Sample 2
The signal emitted from the device can be analyzed and the elemental analysis of each part on the enlarged image can be directly performed in a non-destructive manner.

[Brief description of the drawings]

FIG. 1 is a structural diagram of one embodiment of the present invention.

FIG. 2 is a structural diagram of a specific example of the present invention.

FIG. 3 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 1: sample table 2: sample 3: lens barrel 4: movement mechanism 41: holding part 42: tilt arm 43: rotation / tilt mechanism 5: large bell jar 51: vacuum tank 52: lifting device 6: gantry

Claims (4)

[Claims] 1. A scanning electron microscope that directly scans a sample with a beam to detect emitted or absorbed charged particles and displays an enlarged image, a sample stage on which a large sample is placed and moved, and a narrowly narrowed beam. A lens barrel that emits light and scans the emitted beam, a moving mechanism that positions a beam emitted from the lens barrel from an arbitrary direction at an arbitrary position of the sample on the sample stage, and that the beam is the sample. A detector for detecting charged particles emitted or absorbed when scanning is performed, and a chamber for receiving and vacuuming the sample stage, the lens barrel, the moving mechanism, and the detector. Scanning electron microscope. 2. The scanning electron microscope according to claim 1, wherein said moving mechanism is fixed to said chamber. 3. The scanning electron microscope according to claim 1, further comprising a mechanism for removing the chamber and exchanging a sample, or a mechanism for removing the sample stage and exchanging a sample. 4. The apparatus according to claim 1, further comprising a spacer inserted so as to change the height or size of said chamber in accordance with the height or size of a sample stored in said chamber. Item 4. A scanning electron microscope according to any one of Items 3.