JPH0574183B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention is directed to a dynamic observation display device, in particular, to repeatedly apply mechanical stress to the observed sample itself at high speed, and to apply mechanical stress to the observed sample using an electron beam probe or the like. The present invention relates to a dynamic observation and display device that extracts an image of a specific phase from an image signal obtained by scanning and performs observation and display.

(Technical background and problems) Observing magnetic domains or domains of dielectric materials at specific phases of magnetostrictive elements and electrostrictive elements, etc.
It is important to know the characteristics of various materials.

However, in the past, stress was applied statically and sequentially to the magnetostrictive element, etc., and a scanning line at rest to which the predetermined stress was applied was obtained. For this reason, the scanned image at the time of application of a specific stress under dynamically changing usage conditions does not necessarily match, and sufficient analysis could not be performed.

Furthermore, dynamic changes caused by vibrations in magnetic materials such as electromagnetic steel sheets, which are often used at commercial frequencies, are too slow to be observed using TV scans, etc., making it difficult to observe specific phases.

(Objective and Structure of the Invention) An object of the present invention is to solve the above-mentioned problems, by applying stress to a sample to be observed using a stress generating element, and scanning the sample to be observed with a probe. The objective is to obtain an image of a specific phase when stress is applied by extracting only a signal of a specific phase from among the signals generated from a sample to be observed and displaying it on a display or the like. Therefore, the dynamic observation display device of the present invention changes the stress applied to the observed sample periodically and at high speed, and generates a specific phase from the image signal obtained by irradiating the observed sample with a probe. In a dynamic observation display device that extracts an image and displays it on a display, a stress applying unit that periodically changes the stress applied to the sample to be observed according to a repetition frequency obtained by synchronizing with a horizontal scanning signal of a probe and dividing the frequency thereof. a probe scanning unit that scans the observed sample with a probe, the stress of which is periodically changed by the stress applying unit at the repetition frequency; a signal detection section that detects a signal generated from the observed sample and outputs it as an image signal; and a signal detection section that detects a signal generated from the observed sample and outputs it as an image signal; a specific image extraction section that sequentially extracts image signals of a sufficiently short period of time compared to the above repetition frequency in synchronization with the repetition frequency, and a specific phase in the period of the repetition frequency sequentially extracted by the specific image extraction section. The present invention is characterized in that each of the short-term image signals is associated with successive horizontal scanning lines on the screen of the display, and is expanded and displayed on the horizontal scanning lines.

(Example of the invention) The present invention will be explained in detail below based on the drawings.

FIG. 1 is a configuration diagram of one embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams explaining the configuration of one embodiment of the present invention shown in FIG. 1, and FIG. 4 is a configuration diagram of another embodiment of the present invention. Show the diagram.

In the figure, 1 is the sample to be observed, 2 is the stress generating element, and 3
is a static stress applying screw, 4 is a stress applying device, 5 is an electron gun, 5-1 is an electron source, 5-2 is a Wehnelt cylinder,
5-3 is an anode, 6 is an electron lens, 7 is a scanning coil (X, Y), 8 is a scintillation detector,
9 is a video amplifier, 10 is a signal processing section, 11 is a display, 12 is a scanning electron microscope control section, 13 is a master OSC, 14 and 17 are frequency dividing circuits, 15 is a drive signal generator, and 16 is a horizontal scanning signal generator , 18
19 represents a vertical scanning signal generator, 19 represents a counter, 20 represents a P-ROM, 21 represents a phase switch, and 22 represents a blanking control section.

In FIG. 1, reference numeral 1 indicates a sample to be observed, and a sample moving stage (X,
Stress applying device 4 placed on the device (movable in the Y direction)
It is fixed to . The sample 1 to be observed is held in a sandwiched state from both sides of the stress applying device 4 via the stress generating elements 2, and any static stress can be removed from outside the vacuum by rotating the static stress applying screw 3 shown in the figure. It can be applied as needed.

Further, the electron beam probe that irradiates the observed sample 1 includes an electron source 5-1 (filament), a Wehnelt cylinder 5-2, and an anode 5, which constitute the electron gun 5.
-3 in a known manner. The electron beam probe emitted from the electron gun 5 is imaged by an electron lens 6 onto the sample 1 to be observed in the form of a minute spot (several thousand to several angstroms).
The electron beam probe is deflected by supplying X and Y scanning signals (sawtooth wave currents) from the scanning electron microscope control section 12 to the illustrated scanning coils (X, Y) 7, respectively. As a result, the electron beam probe scans over the sample 1 to be observed. For example, secondary electrons emitted from the observed sample 1 during the scanning are collected and amplified by the illustrated scintillation detector 8. The image signal amplified by the scintillation detector 8 is
The signal is amplified by the video amplifier 9, and is also subjected to signal processing to a predetermined DC level, impedance conversion, etc. The video signal output from the video amplifier 9 is then supplied to a signal processing section 10.

The signal processing section 10 extracts a predetermined image signal from the video signal as will be described later, and supplies it as a luminance signal to, for example, a luminance modulation terminal of the display 11. On the other hand, the signal processing section 10 supplies a predetermined CRT scanning signal as described later to the drive terminals (horizontal and vertical drive terminals) of the display 11 based on the synchronization signal supplied from the scanning electron microscope control section 12. By doing this,
The display 11 displays a secondary electron image emitted from the sample 1 to be observed.

Then, the scanning electron microscope controller 12 controls the stress generating element 2.
For example, when an alternating stress application signal is supplied to the observation sample 1, alternating stress is applied to the observed sample 1, and the displacement of the magnetic domain or the domain of the dielectric material is caused by the magnetostrictive effect or electrostrictive effect depending on the stress. Changes, etc. occur.

However, in the conventional scanning electron microscope, since the sample to be observed 1 is displaced along with the stress application signal, the state of the displacement cannot be observed or displayed even if a TV scanning device with a high scanning speed is used.
Therefore, the present invention supplies a stress application signal that changes periodically and at high speed to the stress generating element 2, and extracts an image signal of a predetermined phase from the signal obtained by scanning the sample 1 to be observed to generate a specific stress. The image at the time of application will be observed and displayed. The operation of the present invention will be explained in detail below with reference to FIGS. 2 and 3.

FIG. 2 is an explanatory diagram for explaining the process of sequentially sampling images of a specific phase from the video signal in synchronization with the stress application signal and displaying them on the display (CRT) 11.

FIG. 2A shows an example of the waveform of the stress application signal, and shows a state in which the stress applied to the sample 1 to be observed changes almost sinusoidally. Luminance signals corresponding to the illustrated specific phases of the stress application signal are sequentially extracted from the video signal and displayed in the form of sequential luminance modulation on the topmost stage of the illustration on the display 11. Similarly, the images are displayed at the next stage in the form of sequential brightness modulation.

FIG. 2B shows a sampling pulse signal waveform for extracting a luminance signal corresponding to a specific phase of the stress signal shown in FIG. 2A from a video signal. The sampling pulse signal is generated by the signal processing section 10 based on the synchronization signal.

FIG. 2C shows a signal waveform for horizontal scanning. The illustrated signal waveform is a sawtooth waveform, and the display 1
1 in the direction of the horizontal line shown in the figure to display an image.

As explained above, according to the sampling method shown in FIG. 2, images obtained when any stress is applied to the sample 1 to be observed can be sequentially and repeatedly sampled and displayed on the display 11.

In addition, Figure 3 shows an image on display 1 when a specific stress is applied using the sampling method shown in Figure 2.
1 is used when a long period of time is required, and is a so-called line sampling method. This will be explained below.

FIG. 3A shows an example waveform of a stress application signal similar to FIG. 2A. Luminance signals corresponding to substantially the same phase portions of each waveform of the stress application signal are sampled from the video signal and displayed in correspondence with one horizontal scanning line on the display 11 from top to bottom as shown in the figure. Ru. In this way, a so-called line sampling method is adopted in which approximately the same phase portions of each waveform of the stress application signal are sequentially displayed line by line from top to bottom on the display 11. Compared to the so-called point sampling method shown in the figure, it is possible to display information at extremely high speed. for example,
When using the point sampling method shown in Figure 2 to obtain 1000 x 1000 pixels on the display 11 using a commercial frequency (50 Hz) repetition period, 2 x 10 ⁴ seconds = 5 hours 33 minutes 20 seconds. It becomes necessary. On the other hand, according to the line sampling method shown in FIG. 3, the time is 20 seconds, and an image of a specific phase when stress is applied can be displayed in an extremely short time.

FIG. 3B shows a pulse signal waveform for line sampling. Using the line sampling pulse signal, the signal processing unit 10 shown in FIG. 1 extracts a luminance signal at a predetermined phase (when a predetermined stress is applied) from the video signal, and displays it on the display 11 in one horizontal scanning line as shown in FIG. It is displayed in correspondence.

FIG. 3C shows an example of the horizontal scanning signal waveform. The horizontal scanning signal example is for horizontally scanning the luminance signal extracted from the video signal by the line sampling pulse signal shown in FIG. 3B so as to correspond to one horizontal scanning line on the display 11.

FIG. 3D shows an example of a sawtooth vertical scanning signal waveform. The sawtooth wave signal is used to cause the horizontal scanning lines shown on the display 11 to be sequentially scanned from top to bottom.

In Fig. 4, EOS is an electron optical system of a scanning electron microscope, which reduces electrons (~25KV) emitted from an electron gun using a magnetic field type lens, and converts the reduced electron beam spot into a small electron beam spot. This serves to form an image on the sample 1 to be observed. 7- in the figure
1, 7-2 and 7-3, 7-4 indicate a vertical scanning coil and a horizontal scanning coil, respectively. This will be explained below.

The clock signal generated by the master OSC 13 is supplied to a frequency divider circuit 14, frequency-divided by 1/N, and then supplied to a drive signal generator 15. The drive signal generator 15 supplies the stress generating element 2 with a drive signal such as the sine wave shown in FIG. 3A, which is generated in synchronization with a clock signal.
A stress varying with the sine wave is applied to the sample 1 to be observed. At this time, a triangular wave, a rectangular wave, etc. may be applied instead of a sine wave, if necessary.

On the other hand, the observed sample 1 is irradiated by the micro electron beam spot emitted from the EOS mentioned above, and the irradiated observed sample 1 emits secondary electrons,
Various signals such as reflected electrons and X-rays are generated. The generated signal, for example secondary electrons, is collected and amplified by the illustrated scintillation detector 8. The amplified signal is amplified and processed by a video amplifier 9, and then supplied to a brightness modulation terminal of a display (CRT) 11.
Note that it is also possible to perform so-called amplitude modulation by superimposing it on the vertical scanning signal as necessary.

In addition, the horizontal scanning signal generator 1 of the clock signal
6, and after being frequency-divided by 1/M by a frequency dividing circuit 17, the signal is supplied to a vertical scanning signal generator 18. The horizontal scanning output signal and vertical scanning output signal generated by the horizontal scanning signal generator 16 and the vertical scanning signal generator 18, respectively, are transmitted to the horizontal scanning coils 7-3, 7-4 of the EOS and the display 11, and Each vertical scanning coil 7
-1, 7-2.

Additionally, the clock signal is provided to a counter 19 for generating an unblanking signal. The counter 19 is connected to the drive signal generator 1.
It is reset each time by the drive start signal supplied from 5, and then starts counting the clock signals. The counted value is P-ROM (20)
The unblanking signal is used as an address to generate various data previously written in the position corresponding to the address in the form of an unblanking signal. A desired phase is selected from the various unblanking signals generated by the phase switch 21,
It is supplied to the blanking control section 22. and,
The unblanking signal output from the blanking control section 22 is displayed on the display (CRT) 11.
is supplied to the unblanking terminal of. As a result, the bright spots on the display (CRT) 11 are unblanked.

According to the above circuit configuration, stress is applied to the observed sample 1 in synchronization with a frequency of f/N, where f is the frequency of the clock signal generated by the master OSC 13. On the other hand, the horizontal scanning of EOS and display 11 is performed at high speed in synchronization with f, and the EOS and display 11
1 vertical scan is performed in synchronization with f/M. Then, unblanking of the display 11 is performed for a specific phase in synchronization with f/N, and an image of the specific phase is displayed on the display 11. As explained above, one cycle of the drive signal is divided into N, and only the image signal of one of the divided phases is selected by the phase switch 21 and displayed on the display 11. . The embodiment shown in FIG. 4 relates to a device that obtains an image of a specific phase when a line scan is possible at high speed compared to a repetitive phenomenon, and is not limited to a scanning electron microscope, but is applicable to particle beams, photon beams, etc. The present invention can also be applied to scanning devices and TV photographing devices that utilize beams, ultrasonic beams, and the like.

(Effects of the Invention) As explained above, according to the present invention, a desired stress is applied to a sample to be observed using a stress generating element, and the sample to be observed is scanned with a probe to generate stress from the sample to be observed. Since a signal with a specific phase is extracted and displayed on a display or the like, an image of a specific phase when stress is applied can be observed and displayed using a simple device.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of one embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams explaining the configuration of one embodiment of the present invention shown in FIG. 1, and FIG. 4 is a scanning electron microscope of FIG. The figure which showed the specific example of a control part and a signal processing part is shown. In the figure, 1 is the sample to be observed, 2 is the stress generating element, and 3
is a static stress applying screw, 4 is a stress applying device, 5 is an electron gun, 5-1 is an electron source, 5-2 is a Wehnelt cylinder,
5-3 is an anode, 6 is an electron lens, 7 is a scanning coil (X, Y), 8 is a scintillation detector,
9 is a video amplifier, 10 is a signal processing section, 11 is a display, 12 is a scanning electron microscope control section, 13 is a master OSC, 14 and 17 are frequency dividing circuits, 15 is a drive signal generator, and 16 is a horizontal scanning signal generator , 18
1 is a vertical scanning signal generator, 16 is a counter, 20 is a P-ROM, 21 is a phase switch, and 22 is a blanking control section.

Claims (1)

[Claims] 1. An operation that periodically and rapidly changes the stress applied to the observed sample and extracts an image of a specific phase from the image signal obtained by irradiating the observed sample with a probe and displays it on a display. a stress applying section that periodically changes the stress applied to the observed sample according to a repetition frequency obtained by dividing the stress in synchronization with a horizontal scanning signal of a probe; A probe scanning unit scans the observed sample whose stress is periodically changed depending on the frequency with a probe, and a signal generated from the observed sample is detected by scanning with the probe scanning unit and an image is generated. a signal detection section that outputs as a signal;
From the image signals output from the signal detection section, image signals having a predetermined phase within the cycle of the repetition frequency and having a sufficiently short period compared to the cycle of the repetition frequency are sequentially extracted in synchronization with the repetition frequency. and a specific image extracting unit, which associates each of the short-term image signals at a specific phase in the cycle of the repetition frequency sequentially extracted by the specific image extracting unit with sequential horizontal scanning lines on the screen of the display. A dynamic observation display device characterized in that the display is expanded and displayed on the horizontal scanning line.