JP2002042711A - Reflection electron detection device of scanning electron microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflection electron detection device of a scanning electron microscope solving a problem of a composite image and a stereoscopic image that can not be switched and observed in the reflection electron detection device constituted by a scintillator and a photomultiplier tube as a semiconductor type reflection electron detector. SOLUTION: The reflection electron detection device is provided with a restriction plate for restricting an amount of reflection electron incident to a detection surface; and a mechanical structure for changing a position of the restriction plate. Thereby, it can be detected by selecting the reflection electron having much composition information and the reflection electron having much convex/concave information. A composition image and a stereoscopic image can be observed by one reflection electron detector comprising a scintillator and a photomultiplier tube.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backscattered electron detector such as a scanning electron microscope, and more particularly to an observation method in a backscattered electron detector comprising a scintillator and a photomultiplier tube.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to the drawings. FIG. 3 shows a schematic diagram of backscattered electron detection by a conventional backscattered electron detection device.

The conventional backscattered electron detector 13 mainly comprises a scintillator 8, a photomultiplier tube 9, and an amplifier circuit 10. In the figure, 1 is an electron beam, 2 is a deflection circuit for scanning the electron beam 1 on the sample 5, 3 is an objective lens for focusing the electron beam on the sample 5, and 4 is a sample chamber. When the electron beam 1 is irradiated, reflected electrons 6 and 7 are generated from the sample 5. The number of electrons 7 reflected at an acute angle with respect to the incident electron beam 1 is larger for heavy elements and smaller for light elements.
That is, the reflected electrons 7 contain a lot of composition information.
Further, the reflected electrons 6 whose reflection angle with respect to the incident beam 1 is large contain a lot of unevenness information. When these reflected electrons are simultaneously detected by the detection surface 15 of the scintillator 8 and amplified by the photomultiplier tube 9 and the amplifier circuit 10, the display device 14
Image with a three-dimensional effect by adding a composition image and a concavo-convex image to the image (solid image)
Is obtained.

[0004]

In the above prior art, it was not possible to detect only the backscattered electrons 7 containing a large amount of composition information. An object of the present invention is to enable observation of two types of images, a composition image and a stereoscopic image, even in a backscattered electron detector composed of a scintillator and a photomultiplier tube.

[0005]

In order to achieve the above object, in a backscattered electron detector comprising a scintillator and a photomultiplier tube, an aperture plate for limiting the amount of reflected electrons incident on a detection surface, and an aperture for the aperture plate It is characterized in that it has a mechanical structure that changes the position of the plate, so that composition images can be observed.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic view of an apparatus according to an embodiment of the present invention, in which a composition image is obtained. The backscattered electron detector 13 according to the present invention includes a scintillator 8, a photomultiplier tube 9, and an amplification circuit 10, an aperture 11, an aperture position change mechanism 12,
Is added. In the figure, 1 is an electron beam, 2 is a deflection circuit for scanning the electron beam 1 on the sample 5, 3 is an objective lens for focusing the electron beam on the sample 5, 4
Is a sample chamber.

When the electron beam 1 is irradiated, reflected electrons 6 and 7 are generated from the sample 5. The backscattered electrons 6 having a large reflection angle with respect to the incident beam 1 contain a lot of sample shape information. The reflected electrons 7 that are reflected at an acute angle with respect to the incident electron beam 1 contain a large amount of sample composition information.

The aperture 11 is provided with a hole so that only the reflected electrons near the incident beam 1 can be detected by the scintillator 8. As shown in the figure, the diaphragm 1 is located between the sample 5 and the scintillator 8.
By inserting 1, it is possible to cut off the backscattered electrons (roughness information) 6 and detect only the backscattered electrons 7 containing a lot of composition information. As a result, the electron energy converted into light on the detection surface 15 is amplified by the photomultiplier tube 9 and the amplifier circuit 10 and is displayed on the display device 14 as an observation image, so that a composition image can be observed.

Next, when it is desired to observe an image having a three-dimensional effect (a three-dimensional image) obtained by adding the composition image and the concavo-convex image, as in the conventional case, the mechanical structure 12 for changing the position of the aperture plate 11 is operated. It becomes possible. As an example, as shown in FIG.
By simply sliding the stop 11 and removing the stop 11 from between the sample 5 and the scintillator 8, the conventional image observation becomes possible. FIG. 2 is a view from the P direction in FIG.

That is, by adding a diaphragm 11 and a mechanical structure for changing the position of the diaphragm to the conventional scintillator-type backscattered electron detector, it is possible to observe two types of images, a composition image and a three-dimensional image, thereby improving the function. Can be achieved.

In addition, the operability is improved because these aperture positions are automatically changed when the operator switches the observation mode. Specifically, in the composition image observation mode, the mechanical structure 12 is controlled such that the aperture plate 11 is in the inserted state 11-a, and in the stereoscopic image observation mode, the aperture plate 11 is in the non-inserted state 11-b.

[0013]

According to the present invention, as described above, one backscattered electron detector comprising a scintillator and a photomultiplier tube is used.
This has the effect of observing a composition image and a stereoscopic image.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a backscattered electron detection device according to an embodiment of the present invention.

FIG. 2 shows a view in the direction P of FIG. 1;

FIG. 3 shows a schematic configuration diagram of a conventional backscattered electron detection device.

[Description of Signs] 1 ... Electron beam, 2 ... Deflection circuit, 3 ... Objective lens, 4 ...
Sample chamber, 5: sample, 6: reflected electrons (irregularity information), 7: reflected electrons (composition information), 8: scintillator, 9: photomultiplier tube, 10: amplifier circuit, 11: diaphragm, 12: diaphragm position change Mechanism: 13: backscattered electron detection device, 14: observation image display circuit, 15: effective detection surface.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shigeru Kawamata 1040, Ichimo, Hitachinaka-shi, Ibaraki F-term in Hitachi Science Systems, Ltd. (reference) 5C033 NN02 NP08

Claims (3)

[Claims] An electron source comprising: an electron source; means for detecting reflected electrons obtained by irradiating a primary electron beam emitted from the electron source; and a display device for displaying a sample image based on the detection signal. In the microscope, the means for detecting the backscattered electrons is of a type in which a scintillator and a photomultiplier are combined, and an aperture plate for limiting the backscattered electrons is provided on the scintillator detection surface. . 2. The backscattered electron detection device according to claim 1, further comprising a mechanism for changing a position of the aperture plate. 3. The detection device according to claim 1, wherein:
A backscattered electron detection device having a mechanism for determining the position of the aperture plate according to a composition image or a stereoscopic image observation mode.