JPS5857248A - Scanning-type electron microscope - Google Patents

Abstract

PURPOSE:To obtain a simple secured synthetic image by supplying a plural kinds of video signals so that they are electronically switched for each scanning line and used as the input to the fluorescent screen of a CRT, and visually synthesizing the video signals into the CRT screen. CONSTITUTION:A reflected electron 5 traveling from the surface of a sample 4 is detected with a detector 7a. Following that, the detected signal is amplified with an amplifier 8a, treated with a signal-treating circuit 9a, and made into an image signal. On the other hand, a secondary electron 6 discharged from a sample 4 is detected with a detector 7b, and the detected signal is made into an image signal by passing through an amplifier 8b and being treated with a signal-treating circuit 9b. The outputs of the circuits 9a and 9b, image signals, are switched alternately through a switching circuit 12, and used as the input to a CRT13. A photographing singal circuit 14 is made to drive a photographing device 15 which photographs the image of the CRT13. The device 15 is made to provide a photograph which is obtained by synthesizing images of the CRT13 which are obtained through the circuits 9a and 9b.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a scanning electron microscope, and more particularly to a scanning electron microscope that obtains a composite image using a plurality of types of signals generated from a sample.

In a scanning electron microscope, methods for obtaining a composite image include combining different types of signals generated from a sample using an electric circuit and inputting this combined signal into a CRT; There is one that inputs each signal to a CRT and synthesizes each photograph obtained thereby.

However, the former has the disadvantage that the electric circuit is complicated and is not suitable for combining several types of signals, and the latter requires skill and processing as it requires all the operations of overprinting the photographed negatives. The drawback was that it took a long time.

An object of the present invention is to provide a scanning electron microscope that can easily and reliably obtain a composite image.

In order to achieve such objective f:, the present invention provides a CRT
A plurality of types of video signals are electronically switched and supplied for each scanning line, and are visually synthesized on the CR and T planes.

Hereinafter, the present invention will be explained in detail using Examples.

FIG. 4 is a configuration diagram showing an embodiment of a scanning electron microscope according to the present invention. In the figure, an electron beam l emitted from an electron gun (not shown) passes between deflection coils 2a and 2b and is focused by an electron lens 3. The focused electron beam 1 is irradiated onto the surface of the sample 4, and the irradiation point is located at the deflection coils 2a and 2b driven by the deflection power source 10.
The four surfaces of the sample are scanned two-dimensionally.

The reflected electrons 5 from the surface of the sample 4 are detected by a detector 7a, and the detection signal is amplified by passing through an amplifier 8a. The amplified signal is processed by the signal processing circuit 9a, and this processed signal becomes an image signal that can be input to CB and T.

On the other hand, the secondary electrons 6 obtained from the sample 4 are detected by the detector 7b, and the detection signal is sent to the amplifier B.
It is designed to be amplified by mediating bl. The amplified signal is processed by the signal processing circuit 9b, and this processed signal becomes an image signal that can be input to the CRT.

Note that the electrons that can be detected by the detector 7b are secondary electrons, but are not limited to this, and include reflected electrons, transmitted electrons,
Auger electrons, X-rays, cathodoluminescence, etc. may be used.

The image signals output from the signal processing circuits 9a and gb are alternately switched via the switching circuit 12, and the CR
It is designed to be input to Tl3. The switching circuit 12 is switched by the output from the scanning signal circuit 11 driven by the deflection power supply 10, and as a result, the screen of the CRT 13 displays electrons that stimulate the fluorescent surface, as shown in FIG. 2(a). The lines are scanned in order from the top to the scanning line 5' corresponding to the output of the signal processing circuit 9a, and the signal processing circuit 9b.
The scanning line 6' corresponds to the output of the signal processing circuit 9a, the scanning line 5' corresponds to the output of the signal processing circuit 9a, and so on. In this case, it goes without saying that the scanning lines may be switched every two as shown in FIG. 2(b).

The switching circuit 12 is also configured to be switched by the photographing signal circuit 14, and once an image is displayed on the CRT 13 using only the image signal from the signal processing circuit 9a, then only the image signal from the signal processing circuit 9b is displayed. This allows images to be displayed on the CRT13. In this case, the photographing signal circuit 14 drives the photographing device 15 for photographing the image on the CRT13.
This photographing device 15 has a CR obtained from the signal processing circuit 9a.
CRTl obtained from the image of Tl3 and the signal processing circuit 9b
You can now obtain a photo that is a composite of the images in step 3 and 3.

In the scanning electron microscope configured in this way, sample 4
As shown in FIG. 3(a), the secondary electrons 6 obtained from the sample 4 are mainly detected as those generated on the surface of the sample 4. Foreign substance 1 contained inside sample 4
The secondary electrons 6a generated at 7 are attenuated inside the sample 4 and are not detected by the detector 7b. Therefore, in the case of a secondary electron image, although it is not suitable for observing the inside of the sample 4, it is optimal for observing the morphology of the surface of the sample 4.

FIG. 4(a) shows a secondary electron image obtained using muscle as sample 4. According to this, only the external shape of the muscle can be observed.

Further, the reflected electrons 5 obtained from the sample 4 are designed to detect information from a foreign substance 17 inside the sample 4, as shown in FIG. 3).

This is because the reflected electrons 5 have almost the same high energy as the incident electrons 1. Therefore, the backscattered electron image is most suitable for observation related to the composition of the sample 4.

FIG. 4(b) is a backscattered electron image obtained using the same muscle as in FIG. 4(a) as sample 4. According to this, a linear transverse striation within the muscle is mainly observed.

Therefore, as in this embodiment, the image signal obtained by secondary electrons and the image signal obtained by reflected electrons are
If each scanning line on the cRT screen is scanned alternately, the visual result will be as shown in Fig. 4 (a) and ('b).
The images shown in FIG. 4 are combined and visualized, and the internal shape of the muscle can be visually seen through the external shape of the muscle, as shown in FIG. 4(C).

FIG. 5 is a block diagram showing another embodiment of the scanning electron microscope according to the present invention. The same symbols as in FIG. 1 indicate the same circuits, etc. In a configuration different from that in FIG. 1, multiple types of signals from the sample 4 are detected by multiple types of detectors 7a to 7d, and are sent to the switching circuit 12 via amplifiers 8a to 8d and signal processing circuits 7a to 7d. selectively switching
This signal is supplied to the RT 13 for signal synthesis. In this way, it is easy to observe a plurality of types of signal images and a composite image of the plurality of types of signals, so that a lot of knowledge about the sample 4 can be obtained easily and quickly.

As is clear from the above description, according to the scanning electron microscope according to the present invention, it is possible to obtain a simple and reliable composite image.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a scanning electron microscope according to the present invention, FIGS. 2(a) and 2(b) are explanatory diagrams showing the mode of scanning on a CRT screen, and FIG. 3(a). (b) is an explanatory diagram showing the movement of electrons detected by the detector, Figures 4 (a) and (b) are diagrams drawn using the output signals of each signal processing circuit, and Figure 4 (C) is an explanatory diagram showing the movement of electrons detected by the detector. FIG. 5 is a configuration diagram of a scanning electron microscope showing another embodiment based on the present invention.

Claims (1)

[Claims] 1. In a scanning electron microscope that scans an electron beam and simultaneously forms a two-dimensional image on a C1'tT fluorescent surface by brightness modulation using a time-series video signal, different complex am
A scanning type electronic device comprising a means for electronically switching and supplying video signals for each scanning line, and visually synthesizing the plurality of video signals on the fluorescent surface of the CRT. microscope.