JPH07302571A - Electron microscope - Google Patents

Abstract

PURPOSE:To provide an X-ray analytic image in a region where a visual field is selected based on an electron microscope. CONSTITUTION:An image based on an electron beam transmitted a sample 6 is stored in a first frame memory of a frame memory 1 by an image pick-up device 12. An electron beam 22 is narrowed down and a signal for tracing a boundary in a rectangular region intending to obtain an x-ray analytic image on the sample by the electron beam 22 is generated. As a result, A signal obtained from the image pick-up device 12 is superimposed on the signal of the electron microscope image, then they are displayed on a display 18. An operator controls the position and size of the rectangular region while observing the image of the boundary superimposed by a luminescent line on the electron microscope image and displayed, and after controlling, switches a signal generated by the frame memory 1 from a signal for tracing to a signal for two-dimensional scanning. The X-ray analytic image of an image obtained by selecting a visual field is displayed on a CRT in the display 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron microscope capable of obtaining an elemental mapping image of a sample.

[0002]

2. Description of the Related Art An electron microscope is used to scan a sample with an electron beam, an X-ray obtained from the sample is detected by an X-ray detector along with this scanning, and the X-ray of the sample is detected based on this detection signal.
A line image is being acquired. Scanning of a sample with an electron beam is indispensable for acquiring such an X-ray image, but in the past, this scanning incorporates a scanning image observing device in an electron microscope, and a scanning signal from this scanning image observing device is used. This is performed by supplying a deflector and scanning the sample with an electron beam.

Such a scanning image observation apparatus has a scanning signal source dedicated to sample scanning, and this scanning signal source can generate a scanning signal capable of scanning from low speed to extremely high speed. Therefore, using an electron microscope incorporating a scanning image observation device, a scanning image of the sample based on secondary electron detection is displayed in real time, the displayed image is observed, and the field of view for elemental mapping is selected. While scanning the field of view with an electron beam, X-rays are detected and an element mapping image is displayed.

[0004]

In the above-mentioned conventional electron microscope, the selection of the field of view for obtaining the X-ray analysis image must be based on the electron beam scanning image, and the transmission electron microscope image of the sample and the secondary electron microscope image. When the scanning images based on electron detection and the like are different, it is not easy to understand which part of the transmission electron microscope image the obtained X-ray analysis image is.

The present invention solves these conventional problems,
An object of the present invention is to provide an electron microscope capable of selecting a field of view for obtaining an X-ray analysis image for a transmission electron microscope image.

Another object of the present invention is to provide an electron microscope which can obtain an X-ray analysis image and is advantageous in terms of manufacturing cost without incorporating a high-priced scanning image observation apparatus.

[0007]

Therefore, in the first aspect of the present invention, a scanning signal for two-dimensionally scanning a sample and a signal for tracing only a boundary portion of a two-dimensionally scanned area are generated by switching. Position specifying signal generating means, control means for controlling switching of signals generated by the position specifying signal generating means, X for deflecting an electron beam based on the signal from the position specifying signal generating means, and A Y-deflector, means for switching the diameter of the electron beam with which the sample is irradiated, imaging means arranged at a position where an electron microscope image is projected, and a signal representing the electron microscope image obtained by the imaging means. And a display means for displaying a mark representing the boundary portion by superimposing it on an electron microscope image based on a signal obtained from the image pickup means when the boundary portion is traced by an electron beam, and an X-ray detector. And X-ray detector for, is characterized in an electron microscope comprising a display means for displaying the X-ray analysis image based on the output signals obtained from the X-ray detector.

A second aspect of the present invention is the frame memory according to the first aspect, wherein the position designation signal generating means for generating a signal for designating a projection position of the electron beam on the sample comprises a scan generator. The device is characterized by an electron microscope.

[0009]

In the present invention, first, the electron microscope image of the sample is projected onto the image pickup means by irradiating the sample with an electron beam having a large diameter in parallel to obtain the electron microscope image. Since the imaging means captures an electron microscope image of the sample, the signal obtained by this imaging is stored, and the stored signal is read to display the sample image. Next, the electron beam with which the sample is irradiated is narrowed down, and a signal for tracing only the boundary portion of the two-dimensionally scanned sample region is switched and generated by the position designation signal generating means. When the projection position of the line on the sample is moved, the electron beam is incident on the position on the image pickup means corresponding to the projection position of the electron beam on the sample, and the signal from this image pickup means is superimposed on the read signal. Then, a specific portion in the electron microscope is displayed in a rectangular bright line on the display device. Therefore, while observing this image, the signal generated by the position designation signal generation means is adjusted so that the rectangle has a desired size at a desired position, and after adjustment, after adjustment by the position designation signal generation means. If a signal for two-dimensionally scanning the rectangle is generated, the two-dimensional scanning is performed by the electron beam with respect to the region on the sample whose field of view is selected in the electron microscope image, and the X-ray obtained from the sample is accompanied by this scanning. If the signal is detected and displayed, an X-ray analysis image of the region selected in the field of view by the electron microscope image can be obtained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an embodiment of the present invention, in which 1 is a frame memory device. This frame memory device 1 has a built-in scan generator,
It is possible to generate a scanning signal. This scanning signal cannot support high-speed scanning, but can support low-speed scanning. The X and Y deflection signals from the frame memory device 1 are supplied to the X and Y deflectors 3x and 3y via the magnification switching circuit 2, respectively. Reference numerals 4 and 5 represent focusing lenses. Exciting currents are supplied to the focusing lenses 4 and 5 from the focusing lens power sources 20 and 21 under the control of the CPU 17. Reference numeral 6 denotes a sample, and the electron beam 22 generated from the electron gun 16 is focused by the focusing lenses 4 and 5 into an electron beam having a desired diameter and irradiated on the sample 6. The electron beam transmitted through the sample 6 is projected onto the fluorescent screen 10 via the objective lens 7, the intermediate lens 8 and the projection lens 9. A photographic device 11 including a photographic film is arranged below the fluorescent screen 10, and an image pickup device 12 such as an image pickup tube is arranged below the photographic device 11.
The fluorescent screen 10 can be flipped up as shown by a dotted line so as to be removed from the electron beam optical path. Reference numeral 13 is an energy dispersive X-ray detector. The energy dispersive X-ray detector 13 has a built-in pulse height analyzer, and the window of the pulse height analyzer is set so as to selectively pass only the characteristic X-rays related to the target element. The signal from the energy dispersive X-ray detector 13 is sent to the pulse counter 14. The output signal of the pulse counter 14 can be supplied to the frame memory device 1 via the bus line 15 under the control of the CPU 17. The output signal from the frame memory device 1 can be supplied to the display device 18 under the control of the CPU 17.
Reference numeral 19 is an operator console, and 22 is an electron beam.

In such a structure, first, in order to select a region in which the mapping image of the target element is to be displayed, the operation console 19 instructs the display device 18 to display an electron microscope image. As a result, the fluorescent plate 10 is flipped up to be removed from the optical path, and the photographic film of the photographic device 11 is also removed from the optical path, so that the sample image is directly projected on the imaging device 12. Therefore, the electron beam from the electron gun 16 is irradiated onto the sample 6 in parallel through the focusing lenses 4 and 5. Sample 6
The electron beam that has passed through is the objective, intermediate, and projection lens 7, 8, 9
And the sample image is projected on the imaging device 11. The sample image is converted into an electric signal by the image pickup device 11, and the electric signal generated by this conversion is stored in the first frame memory of the frame memory device 1. The video signal representing the electron microscope image stored in the first frame memory of the frame memory device 1 is read out under the control of the CPU 17 and supplied to the display device 18, and the C signal contained in the display device 18 is read.
An electron microscope image of the sample is displayed on the RT. Therefore, the operator console 19 is instructed to change to the scanning image mode. As a result, the focusing lens power source 20, based on the control of the CPU 17,
The exciting current supplied from 21 to the focusing lenses 4 and 5 is changed, and the sample 6 is irradiated with the electron beam 22 that is narrowed down. Then, next, the operator console 19 is instructed to trace the rectangular boundary portion on which the element mapping image is to be displayed on the sample 6 with the electron beam 22. When the number of pixels in the x and y directions when two-dimensionally scanning the sample 6 from the frame memory device 1 is m and n, respectively, the following pixels are supported by the frame memory device 1 under the control of the CPU 17. A signal for sequentially irradiating each point to be irradiated with an electron beam is generated. P11, P21, P31, ..., Pm1, P12, Pm2, P13, Pm
3, ..., P1 (n-1), Pm (n-1), P1n, P2n, P3n,
, Pmn The above-mentioned signals are transmitted through the magnification switching circuit 2 to the electron beam deflector 3
Since it is supplied to x and 3y, the boundary portion 24 of the rectangular area 23 on the sample 6 is traced by the electron beam 22 as shown in FIG. Since the electron beam projected onto the sample 6 is narrowed down, a sample image sufficient for field selection is no longer formed on the imaging device 11. However, since the imaging lens system is maintained in the electron microscope image mode, when the point A on the sample 6 in FIG. 2 is irradiated with the electron beam, it is formed on the imaging device 11 as shown in FIG. An electron beam is applied to a point A'corresponding to the point A in the electron microscope image which has been formed. Therefore, the boundary of the rectangular area is traced by the electron beam even on the imaging device 11. The signal thus obtained from the image pickup device 11 is stored in the second frame memory of the frame memory device 1. Further, the signal from the second frame memory is added to the signal from the first frame memory and stored in the third frame memory. On the other hand, since the signal from the third frame memory is read out and supplied to the display device 18 instead of the signal from the first frame memory, the CRT built in the display device 18 is superimposed on the electron microscope image. Then, a rectangular bright line 25 as shown in FIG. 3 is displayed. Since each of the above processes is repeatedly performed in real time, when the operator operates the console 19 to change the boundary position of the rectangular area to be traced on the sample, the rectangular bright line displayed on the CRT incorporated in the display device 18 is changed. The position of 25 also moves. Therefore, the operator operates the console 19 while observing the image displayed on the display device 18, and outputs the signal for tracing the boundary portion of the rectangular area on the sample in the x direction and the y direction.
A desired bias in the direction is added, the position of the rectangular bright line 25 displayed on the CRT is moved by an arbitrary amount, and a magnification switching signal is sent to the magnification switching circuit 2 to adjust its size to adjust the rectangular bright line. To the field of view for which the element mapping image is to be displayed.

Upon completion of such visual field selection, the operator console 19 is instructed to acquire an element mapping image. As a result, the frame memory device 1 generates a signal for two-dimensionally scanning the rectangular area whose boundary is traced by the electron beam 22 on the sample 6. As a result, the rectangular area on the sample 6 is two-dimensionally scanned by the electron beam 22, and the X-ray generated from the sample due to this scanning is detected by the energy dispersive X-ray detector 13. Energy dispersive X-ray detector 13
The pulses detected and selected by the pulse counter 14 are counted by the pulse counter 14, and the count value signal is supplied to the fourth frame memory of the frame memory device 1 and stored in correspondence with pixels. Since the signal from the fourth frame memory of the frame memory device 1 is read out and supplied to the display device 18 under the control of the CPU 17, the CRT built in the display device 18 has the field of view previously selected. An elemental mapping image of the region on the sample is displayed.

According to the apparatus based on the above-mentioned embodiment, without incorporating a dedicated scanning image observation apparatus in the electron microscope,
By using a scan signal from a scan generator built in the frame memory device, it is possible to perform a two-dimensional scan on a sample for selecting a field of view for displaying an X-ray analysis image and acquiring an element mapping image. Therefore, it is possible to provide an electron microscope which can display an element mapping image of a desired visual field and is advantageous in terms of manufacturing cost.

In the above-described embodiment, the frame memory device having the built-in scan generator is used as the position designation signal generating means, but the boundary between the scanning signal for two-dimensionally scanning the sample and the two-dimensionally scanned region is used. Any device other than the frame memory device may be used as the position designation signal generating means as long as a signal for tracing only a portion can be generated by switching. In that case, it is necessary to provide the memory separately.

Further, in the above-mentioned embodiment, in order to display the region where the X-ray analysis image is to be obtained, the sample is raced in a rectangular shape by the electron beam, but the X-ray analysis image is displayed. It suffices if the area can be superimposed on the electron microscope image and displayed by a bright line or the like. Therefore, the figure traced by the electron beam on the sample is a part of a rectangle or a rectangular shape as shown in FIGS. Only in the corner.

In the above-described embodiment, first, the electron microscope image is exposed on the film of the photographing device 11, and then the rectangle for displaying the X-ray analysis image is traced by the electron beam narrowed down. If the film is overexposed during the operation, the area where the X-ray analysis image is displayed can be recorded as a photograph.

Further, the display device 1 in the above-mentioned embodiment.
8 may include a CRT for displaying a visual field selection image and a CRT for displaying an X-ray analysis image, or may be a single CR.
It is also possible to display the image by selectively switching the field-of-view selection image and the X-ray analysis image provided with T, and further, the screen of a single CRT is divided, and the field-of-view selection image is displayed on half of the screen. An X-ray analysis image may be displayed in half.

Furthermore, in the above-described embodiment, the rectangle is displayed as a bright line, but the boundary of the two-dimensionally scanned area is clearly identifiable such that it is displayed by a color difference without depending on the bright line. If displayed, it can be implemented in other display forms.

[0019]

According to the first aspect of the present invention, a position designation signal which can be generated by switching between a scanning signal for two-dimensionally scanning a sample and a signal for tracing only a boundary portion of a two-dimensionally scanned region. Generating means, control means for controlling switching of signals generated by the position designation signal generating means, and X and Y deflectors for deflecting an electron beam based on signals from the position designation signal generating means. A means for switching the diameter of the electron beam irradiated on the sample, an image pickup means arranged at a position where the electron microscope image is projected, and a signal and an electron beam representing the electron microscope image obtained by the image pickup means. Display means for displaying a mark representing the boundary portion by superimposing it on an electron microscope image based on a signal obtained from an image pickup means when tracing the boundary portion, and X for detecting X-rays. Since the detector and the display means for displaying the X-ray analysis image based on the output signal obtained from the X-ray detector are provided, according to the first aspect of the present invention, the electron microscope captured by the imaging means. 2 superimposed on the image
Since the boundary portion of the dimensional scanning region is displayed as a mark, the region in which the X-ray analysis image is to be obtained can be selected based on the electron microscope image.

In addition, since the area displayed as a mark superimposed on the electron microscope image is not affected by the magnification of the electron microscope image or the image rotation, it is possible to always select an error-free visual field.

In the second aspect of the present invention, since the frame memory device having the built-in scan generator is used as the position designation signal generating means, the X-ray can be obtained for a desired visual field without incorporating a high-priced scanning image observation device. An analytical image can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing an apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a trace by an electron beam at a boundary portion of a rectangular region on a sample for which an element mapping image is to be obtained and a trace of the electron beam on an image pickup means accompanied therewith.

FIG. 3 is a diagram for illustrating a display screen of a CRT with a built-in display device 18 in which a boundary between rectangular regions for which an electron microscope image and an element mapping image are to be obtained is displayed as a bright line.

FIG. 4 is a view showing another embodiment for tracing the boundary of a rectangular area with an electron beam.

[Explanation of symbols]

 1: Frame memory device 2: Magnification switching circuit 3x, 3y: Electron beam deflector 4,5: Focusing lens 6: Sample 7: Objective lens 8: Intermediate lens 9: Projection lens 10: Fluorescent plate 11: Photographing device 12: Imaging Device 13: Non-dispersive X-ray detector 14: Pulse counter 15: Bus line 17: CPU 18: Display device 19: Operator console 20, 21: Focusing lens power supply 22: Electron beam 23: Rectangular area 24: Boundary of rectangular area Part A: Point on boundary of rectangular area 25: Rectangular bright line

Claims (2)

[Claims] 1. A position designation signal generating means capable of switching and generating a scanning signal for two-dimensionally scanning a sample and a signal for tracing only a boundary portion of a two-dimensionally scanned region, and the position designation signal. Control means for controlling switching of the signal generated by the generating means, X and Y deflectors for deflecting the electron beam based on the signal from the position designation signal generating means, and electrons irradiated on the sample. A means for switching the diameter of the wire, an imaging means arranged at a position where the electron microscope image is projected, and a signal representing the electron microscope image obtained by the imaging means and the electron beam trace the boundary portion. At this time, based on a signal obtained from the image pickup means, a display means for displaying a mark representing the boundary portion by superimposing it on an electron microscope image, an X-ray detector for detecting X-rays, and an X-ray detector. Than An electron microscope comprising display means for displaying an X-ray analysis image based on the obtained output signal. 2. The electron microscope according to claim 1, wherein the position designation signal generating means for generating a signal for designating the projection position of the electron beam on the sample is a frame memory device equipped with a scan generator.