JPH07192678A - Reflecting electron detector - Google Patents

Abstract

PURPOSE:To low suppress a cost while ensuring efficiency of detecting a reflecting electron by providing two or more reflecting electron sensitive parts in a sensitive part mounting surface by interposing an electron beam transmitting hole, providing a photomultiplier by one piece, and arranging a reflecting member in a light guide part. CONSTITUTION:A reflecting electron detector 10 is formed by interposing an electron beam transmitting hole 19, to provide a surface, facing a sample at mounting time, to serve as sensitive part mounting surfaces 18a, 18b, and the first/second reflecting electron sensitive parts 12a, 12b are mounted on each mounting surface 18a, 18b. A cylindrical connection part for connecting a photomultiplier (PMT) 15, receiving light emitted by the reflecting electron sensitive parts 12a, 12b converted into an electric signal and amplified, is formed in one end of a light guide part 11. The other end part is formed in a roof shape, and aluminum is evaporated in the external surface, to form mirrors 13a, 13b. In these mirrors 13a, 13b, light emitted by the first reflecting electron sensitive part 12a is respectively reflected and guided to the photomultiplier through the connection part passing a part 11d not cut by a notched part 17 of the light guide part 11.

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, and more particularly to a backscattered electron sensing section for receiving backscattered electrons from a sample irradiated with an electron beam on a sensing surface and outputting light, and a backscattered electron sensing section. A photomultiplier tube for converting to and amplifying the photoelectron multiplier, and a light guide section to which the above-mentioned backscattered electron sensing section and photomultiplier tube are attached and which guides light from the backscattered electron sensing section to the photomultiplier tube. The present invention relates to a backscattered electron detector of an electron beam device.

[0002]

2. Description of the Related Art As a backscattered electron detector of an electron beam device such as an electron microscope in the related art, there are a type using a phosphor or a plastic scintillator and a type using a semiconductor. One of the types shown in FIG. 5 is shown in FIG.
(See JP-A-249843).

The sample 4 is placed in a sample chamber 1 of an electron microscope having an objective lens 3 provided above, and a photomultiplier tube 8 and an amplifier 9 are connected to one end of a main body which is a light guide section. The line transmission hole 6a is formed, and the scintillator 6 serving as a backscattered electron sensing portion is arranged. In such a backscattered electron detection device, among the backscattered electrons 5, those detected by the scintillator in the direction opposite to the photomultiplier tube are blocked by the transmission hole, and the optical path to the photomultiplier tube is complicated,
It becomes difficult for light to reach the photomultiplier tube, resulting in low detection efficiency of backscattered electrons.

With this in mind, the applicant of the present application has proposed the following backscattered electron detection device (Japanese Patent Laid-Open No. 4-24).
9843). As shown in FIG. 6, this has a photomultiplier tube 8 and an amplifier 9, and is formed by a light guide section which is a transparent body, and two scintillators 7, 7 which are backscattered electron sensing sections are provided. , A notch for passing an electron beam is provided at the tip of each of these scintillators, and these tips are arranged close to each other so that the electron beam is transmitted between the two scintillators 7 and 7 and the reflected electrons from the sample are One scintillator 7, 7 is used for efficient detection.

[0005]

The above-mentioned second problem
In the backscattered electron detector of, the photomultiplier tube and the amplifier for converting the light emitted from the backscattered electron sensing section of the scintillator into an electric signal and amplifying it must be individually provided for each scintillator. However, there is a problem in that the manufacturing cost becomes very high.

Therefore, an object of the present invention is to provide a backscattered electron detector capable of keeping the cost low while ensuring the detection efficiency of backscattered electrons.

[0007]

Means for Solving the Problems A backscattered electron receiving section for receiving backscattered electrons from a sample irradiated with an electron beam on a sensitive surface and outputting light, and a photomultiplier tube for converting and amplifying light into electrons. When,
The backscattered electron sensing section and the photomultiplier tube are attached,
In a backscattered electron detector of an electron beam apparatus including a light guide section for guiding light from a backscattered electron sensing section to a photomultiplier tube, an electron beam transmission hole through which an electron beam passes, and this electron beam A plurality of sensing portion mounting surfaces for mounting the electron beam sensing portion facing the sample are provided with a transmission hole interposed, and two or more backscattered electron sensing portions are attached to the sensing portion mounting surface to transmit electron beams. The photomultiplier tube is provided by sandwiching the hole, and the light guide section is provided with a reflecting member for reflecting the light from the backscattered electron sensing section and introducing the light into the photomultiplier tube. .

In the present invention, the backscattered electron sensing portion may be a prefabricated one obtained by coating the substrate with a phosphor.

[0009]

According to the present invention, the backscattered electrons from the sample are efficiently converted into light by the plurality of backscattered electron sensing parts mounted on the sensing part mounting surface toward the sample, and enter the light guiding part. All the light is directly or reflected by the reflecting member and is incident on one photomultiplier tube, converted into an electric signal and amplified.

Therefore, a plurality of backscattered electron receiving sections can efficiently detect backscattered electrons, and a single photomultiplier tube for amplifying the optical signal from the backscattered electron receiving section as an electric signal is required. Accordingly, one series of amplifiers and the like is sufficient, and the amplification system can be simplified and the cost can be reduced. Further, a plurality of standard types of backscattered electron sensitizers can be prepared in advance, and it is not necessary to specially form them on the main body of the detection device, so that the cost can be further reduced.

[0011]

Embodiments of the backscattered electron detector according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the entire structure of a first embodiment of a backscattered electron detector according to the present invention, and FIG. 2 is a perspective view showing a backscattered electron sensing section of this backscattered electron detector. In this embodiment, the backscattered electron detector 10 has two backscattered electron sensing portions 12 in the shape of a disk. In this embodiment, the light guide portion 11 made of glass or transparent constituent resin is used.
As shown in FIG. 1, a trapezoidal notch 17 is formed in the center of the notch 17 to a depth of about half of its width, and an electron beam that transmits an electron beam is transmitted to the upper surface of the notch 18. Hole 19 is opened.

Further, in this embodiment, the electron beam transmitting hole 1
It is formed by sandwiching 9 and a surface facing the sample at the time of mounting is provided,
Sensing part mounting surfaces 18a, 18b, each mounting surface 18a, 1
The first and second backscattered electron sensing portions 12a and 12b are attached to 8b. Reference numeral 16 is an amplifier for amplifying and processing the signal of the photomultiplier tube 15, and 17 is a CRT which is a display means for displaying an electron beam image.

A photomultiplier tube (PMT) 15 for converting the light emitted from the backscattered electron sensing portions 12a and 12b into an electric signal for amplification is connected to one end of the light guide portion 11. The cylindrical connection portion 14 is formed, the other end portion is formed into a roof shape, and aluminum is vapor-deposited on the outer surface thereof to form the mirrors 13a and 13b. This mirror 13a,
Reference numerals 13b respectively reflect the light emitted from the first backscattered electron sensitive section 12a, pass through the portion 11d of the light guide section 11 that is not cut out by the cutout section 17, and through the connection section. To guide the photomultiplier tube (an example of the optical path is shown by an arrow A in FIG. 1).

Here, in the present embodiment, the backscattered electron receiving section 12 is a phosphor scintillator in which a phosphor 12B is applied to one surface of a circular glass plate 12A as shown in FIG. , Produce many at once. The shape of the backscattered electron sensitive portion is not limited to a circle, but may be a quadrangle or another polygon.

Therefore, according to this embodiment, the reflected electrons are
Light is output after being detected by the two backscattered electron receiving sections 12a and 12b. Here, the light from the first backscattered electron sensitive section 12a is reflected by the mirrors 13a and 13b and enters the photomultiplier tube, and the light from the second backscattered electron sensitive section 12a is Since it directly enters the photomultiplier tube, even if there is only one photomultiplier tube and one amplification system, the information from the two backscattered electron sensing parts can be taken in as a signal without omission, which is low cost and high efficiency. Backscattered electron detector.

FIG. 3 is a plan view showing a second embodiment of the backscattered electron detector according to the present invention. In the present embodiment, the backscattered electron detector 20 includes three backscattered electron sensing sections 12 (1
2a, 12b, 12c) are provided. In this embodiment, as in the first embodiment, the light guide portion 21 made of glass or transparent constituent resin is provided at the center as shown in FIG.
An electron beam transmitting hole 2 through which an electron beam is transmitted is formed on the upper surface of the notch 22 while forming a notch 22 that is a roof-like recess.
3 is formed, and the electron beam transmission hole 23 is sandwiched between
A surface facing the sample is provided at the time of mounting, and the sensing section mounting surfaces 22a, 2
2b and 22c, and the first to third backscattered electron sensing portions 12a, 12b and 12c are mounted on the respective mounting surfaces.

Reference numeral 16 is an amplifier for amplifying and processing the signal of the photomultiplier tube 15, and 17 is a CRT which is a display means for displaying an electron beam image. Then, at one end of the light guide portion 21, a cylindrical connection portion 14 for connecting the photomultiplier tube (PMT) 15 is formed as in the first embodiment, and the other two sides are connected. , Roof-shaped, and aluminum is vapor-deposited on the outer surface thereof to form mirrors 24a, 24b, 24
c, 24d, and 24e are formed. The mirrors 13a to 13e are connected to the first and second backscattered electron sensing portions 12 described above.
The light emitted from a and 12b is reflected twice or three times, and is guided to the photomultiplier tube through the connection part through the part of the light guide part 21 not cut by the cutout part 22. (Fig. 1
An example of the optical path is shown by the middle arrows B and C).

Therefore, according to this embodiment, the reflected electrons are
Light is output after being detected by the three backscattered electron sensing units 12a, 12b, 12c. Here, the first backscattered electron sensing unit 1
The light from 2a is reflected by, for example, the mirrors 24a, 24b, and 24e, and enters the photomultiplier tube as indicated by an arrow B, and the light from the second backscattered electron sensing unit 12b is, for example, the mirror 24.
c, 24d, and is incident on the photomultiplier tube as indicated by arrow C. Further, the light from the third backscattered electron sensing section 12c is directly incident on the photomultiplier tube. Even if there is only one multiplier and one amplification system, the information from the three backscattered electron sensing parts can be taken in as signals without omission, so that a backscattered electron detector with low cost and higher efficiency can be obtained. it can.

FIG. 4 is a plan view showing a third embodiment of the backscattered electron detector according to the present invention. In the present embodiment, the backscattered electron detector 30 includes four backscattered electron sensing units 12 (1
2a, 12b, 12c, 12d) are provided. Further, as shown in FIG. 3, the light guide portion 31 is provided with a notch portion 32, which is a roof-like concave portion, at the center portion. Then, an electron beam transmission hole 33 through which an electron beam is transmitted is formed on the upper surface of the cutout portion 32, and a surface facing the sample is provided with the electron beam transmission hole 23 sandwiched between the sensing portion mounting surfaces 32a, 32b, 32c. ，
32d, and the first to third backscattered electron sensing portions 12a, 12b, 12c, 12d are mounted on each mounting surface,
A reflecting surface is formed on the light guide portion 31 in a roof shape, and aluminum is vapor-deposited on the outer surface thereof to form mirrors 34a, 34b, 34c, 3
4d, 34e, 34f are formed. The mirrors 34a to 34f respectively reflect the light emitted from the first, second, and fourth backscattered electron sensing sections 12a, 12b, and 12d, and are reflected by the cutout section 22 of the light guide section 31. The light is guided to the photomultiplier tube through the above-mentioned connecting portion through the portion not cut out (an example of its optical path is shown by arrows E, F and G in FIG. 4). In addition, the light from the third backscattered electron sensing section 12c is
Since the light directly enters the photomultiplier tube 14 (arrow H in FIG. 4), the efficiency is further improved.

The present invention is not limited to the above embodiment, and any number and position of electron beam transmission holes may be arranged around the electron beam transmission hole, and the position and shape of the mirror may be reflected electron sensitive. There is no particular limitation as long as it guides the light from the section to the photomultiplier tube.

[0021]

As described above, according to the present invention,
The reflected electrons from the sample are efficiently converted into light by the plurality of reflected electron sensing units mounted on the sensing unit mounting surface toward the sample, and enter the light guiding unit. All the light is directly or reflected by a mirror and is incident on one photomultiplier tube, converted into an electric signal and amplified, so that the plurality of backscattered electron sensing sections can efficiently detect backscattered electrons. However, only one photomultiplier tube is required for amplifying the optical signal from the backscattered electron sensing section as an electric signal, and accordingly, only one series of amplifiers and the like is sufficient, which simplifies the amplification system and reduces costs. There is an effect that it can be made low.

Further, a plurality of standard types of backscattered electron sensitizers can be prepared in advance, and it is not necessary to specially form them in the main body of the detection device, so that the cost can be further reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a structure of a first embodiment of a backscattered electron detector according to the present invention.

2 is a perspective view showing a backscattered electron sensing section of the backscattered electron detector shown in FIG. 1. FIG.

FIG. 3 is a plan view showing the structure of a second embodiment of the backscattered electron detector according to the present invention.

FIG. 4 is a perspective view showing a structure of a backscattered electron detector according to a third embodiment of the present invention.

FIG. 5 is a diagram showing a conventional backscattered electron detector.

FIG. 6 is a diagram showing another example of a conventional backscattered electron detector.

[Explanation of symbols]

 10 Reflection Electron Detector 11 Light Guide Part 12 Reflection Electron Sensing Part 13a, 13b Mirror 15 Photomultiplier Tube 18a, 18b Sensing Part Attachment Surface 19 Electron Beam Transmission Hole

Claims (2)

[Claims] 1. A backscattered electron sensing section for receiving backscattered electrons from a sample irradiated with an electron beam on a sensing surface and outputting light, a photomultiplier tube for converting light into electrons and amplifying the electrons, and the above-mentioned reflection. In the backscattered electron detector of the electron beam device, which is provided with an electron receiving section and a photomultiplier tube, and which has a light guide section for guiding the light from the backscattered electron receiving section to the photomultiplier tube, An electron beam transmitting hole through which an electron beam passes, and a plurality of sensing unit mounting surfaces for mounting the electron beam sensing unit facing the sample, sandwiching the electron beam transmitting hole, are provided. Two or more backscattered electron sensitizers are provided on both sides of the electron beam transmission hole, and a single photomultiplier tube is provided. A backscattered electron detector characterized in that a reflection member to be introduced into the multiplier tube is arranged. 2. The backscattered electron detector according to claim 1, wherein the backscattered electron receiving section is prepared by coating a substrate with a phosphor and is manufactured in advance.