JPS6147047A - Method of analyzing crystalline tissue of sample - Google Patents

Abstract

PURPOSE:To analyze the crystalline tissue of the sample by scanning an electron beam with a given incidence angle over the sample surface by installing an additional deflecting coil near the deflecting coil located in the middle between the convergent lens and the objective. CONSTITUTION:An additional deflecting coil 4 is installed near a deflecting coil 3 located in the middle between a convergent lens 2 and an objective 5 to scan an electron beam with a given incidence angle over the surface of a sample 7 divided into many picture elements by means of a digital scanning power supply 12. And, the amount of electrons reflected by the sample surface is detected by a reflected electron detector 6. After a reflected electron signal is amplified by an image signal amplifier 9, the amount of the amplified signal is digitized by means of an A/D converter 13. Then the thus obtained digitized value is stored as image information in a memory, a floppy disk 14, a hard disk 15, etc. installed in a CPU11 synchrnously with shifting of the address of the picture element performed by a digital scanning power supply 12. Accordingly, thus digitized values are classified into several stages according to the display program and the crystalline particle information for each color of picture elements is displayed on a color displayer 17.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for analyzing the crystalline structure of a sample in which the surface of the sample is scanned by an electron beam while maintaining a constant electron beam incidence angle. .

[Conventional technology]

There are various substances that have crystal structures, and xlIA diffraction and electron beam diffraction are used to analyze their crystal structures.

(Problems to be Solved by the Invention) However, when using X-ray diffraction, for example, the analysis location on the sample has a wide X-ray irradiation area, making it difficult to diffract microscopic parts. Since observation is performed using an optical microscope, etc., there is a problem in that it is not possible to perform observations in conjunction with analyzes such as transmission electron microscopy images or scanning electron microscopy images of crystal grains.Furthermore, when using electron beam diffraction, Although it is possible to perform observation in conjunction with analysis such as transmission electron microscopy images and scanning electron microscopy images of crystal grains, it is possible to conduct observations in combination with analysis such as transmission electron microscopy images and scanning electron microscopy images of crystal grains. There is a problem in that it is not possible to process the data display to determine what kind of crystal structure the crystal structure has and which locations have the same crystallinity.The present invention aims to solve the above-mentioned problems. It is an object of the present invention to provide a method for analyzing sample crystallinity lines, which makes it possible to easily analyze the crystal structure of a sample.

[Means for Solving the Problems] For this purpose, the method for analyzing the crystalline structure of a sample according to the present invention focuses an electron beam from an electron gun on the upper focal point of an objective lens using a converging lens, and A method for analyzing the crystalline structure of a sample using an electron microscope that emits parallel beams, in which a constant electron beam incidence angle is applied to a deflection coil located between a converging lens and an objective lens. An additional deflection coil is installed to scan the electron beam over the surface of the sample while holding the sample, and the amount of reflected electrons is detected by dividing the sample into many pixels while maintaining a constant electron beam incidence angle and scanning the surface with the electron beam. The method is characterized in that the amount of reflected electrons is quantified to analyze the crystal structure of the sample.

[Effect]

In the method of analyzing the crystalline structure of a sample according to the present invention, the electron beam is scanned over the surface of the sample while maintaining a constant electron beam incidence angle using an additional deflection coil, the amount of reflected electrons is detected, and the amount is further digitized and classified into levels. Therefore, reflected electron signals corresponding to differences in the lattice spacing of crystal grains, differences in crystal orientation of crystal grains, etc. can be obtained. Therefore, the crystal grains can be recognized by displaying them in pseudo-color, and by irradiating the sample with an electron beam by changing only the incident angle without moving the irradiation point on the sample. By displaying the electron channeling pattern information
Capable of recognizing crystal grains and analyzing crystal structure.

〔Example〕

Examples will be described below with reference to the drawings.

FIG. 1 is a diagram showing the system configuration of one embodiment of the present invention, and FIG.
The figure is a diagram explaining each observation mode.

In the figure, 1 is an electron gun, 2 is a converging lens, 3 is a deflection coil, 4 is an additional deflection coil, 5 is an objective lens, 6 is a backscattered electron detector, 7 is a sample, 8 is a deflection switching adjuster, and 9 is an image Signal amplifier, 10 is CRT for observation, 11 is CPU (central processing unit), 12 is digital scanning power supply, 13 is A/
A D converter, 14 a floppy disk, 15 a hard disk, 16 a console, 17 a color display, and 18 a frame memory.

In FIG. 1, an electron beam from an electron gun 1 is focused by a converging lens 2 onto the upper focal point of an objective lens 5, and is irradiated by the objective lens 5 onto the surface of a sample 7 as a parallel beam. The amount of backscattered electrons due to the irradiation is detected by a backscattered electron detector 6, and amplified by an amplifier 9.
The signal is sent to the A/D converter 13 for display and is also sent to the A/D converter 13. The reflected electron signal sent to the A/D converter 13 is digitized here, then processed by the CP Ull and sent to the built-in memory or floppy disk of the CPυ11.
The information is stored as image information on the disk 14, hard disk 15, etc., and is further displayed in pseudo color on the color display 17.

The present invention provides an additional deflection coil 4 to the deflection coil 3 located between the converging lens 2 and the objective lens 5 in the electronic Igi mirror, as shown in FIG. The crystal structure of the sample is analyzed based on the image information obtained by scanning the surface of the sample with an electron beam while maintaining the linear incidence angle and the conventional ECP information. That is, by providing the additional deflection coil 4, the electron beam as shown in FIG.
Channeling pattern mode <ECP mode),
Figure 2 Ib1V! Constant angle of incidence plane scanning mode as shown in J.
and FIG. 2 (scanning electron microscope image mode as shown in C1)
38M mode) can be realized.

In the constant incident angle surface scanning mode, as shown in FIG. , the surface of the sample 7 is divided into a large number of pixels (generally 1000 x 1000 pixels), and the surface is scanned.
A backscattered electron detector 6 detects the amount of backscattered electrons resulting from the surface scanning. The detected backscattered electron signal is amplified by the video signal amplifier 9 and then sent to the A/D converter 13 (approximately 8 bits;
The signal amount is digitized in 102411 (102411 tone). This numerical value is C
Under the control of the PLIII, the internal memory of the CPU II, the floppy disk 14, and the hard disk 1 are synchronized with the pixel address movement (area scanning) of the digital scanning power supply 12.
In the 0M image information stored as image information in 5 etc., almost the same numerical values are obtained for each identical crystal grain on the sample T.
Since surface scanning is performed with the electron beam incident angle θ constant, if the lattice spacing 2d of the crystal grains differs or the crystal orientation of the crystal grains differs on the sample 7, the data will be reflected as the corresponding reflected electron signal. will be recorded.

The relationship between the irradiation beam and the sample crystal is λ−2dsinθ λ: Wavelength of irradiated electron beam (Determined by accelerating voltage) 2d: Lattice spacing of sample crystal θ: Electron beam incidence angle It is expressed as

CPυ11 built-in memory and floppy disk 14,
The data stored on the hard disk 15 etc. is CPυ
11, the numerical values are classified into several levels according to the display program and displayed on the color display 17.

Color-coded crystal grain information for each pixel is displayed for surface analysis.

In addition, when storing the digitized value of the reflected electron signal as image information in memory, the frame memory 18 can be used in addition to the above-mentioned CPU II built-in memory, floppy disk 14, hard disk 15, and other memories. Accordingly, it is also possible to directly capture surface information and display it on the color display 17 at high speed.

The advantage of using A/D conversion to classify the levels is that by displaying the colors in pseudo-color, it is possible to more easily recognize crystal grains. However, when the amount of backscattered electrons differs or the beam scanning area is large, the amount of signals received at the center of the scanning plane and the center of the scanning plane and at the detector may differ slightly depending on the positional relationship between the beam irradiation position and the detector. Sample 7
There is a phenomenon where the signal amount becomes a sloped value on the left and right (top and bottom) screens due to the slope of the screen, etc., but by applying the processing described above, from one value to another value can be within the same numerical range. Since it can be divided into levels and converted into one f (color designation), it is possible to correct the conditions of the sample 7, etc.

On the other hand, the signal that does not pass through the A/D converter 13 is transmitted to the observation CR.
It can be observed as a normal backscattered electron scanning image using TIO.

Here, since signal value conversion processing is not performed, it is difficult to emphasize and observe slight changes in the lattice spacing 2d of crystal grains. However, it is convenient for controlling the crystal grain distribution state and position on the sample 7.

Crystal grains can be recognized as described above by A/D converting the backscattered electron signal and dividing it into levels, but in order to find out what kind of crystal structure the crystal grain has and to correlate it with the image, it is necessary to Simply change the deflection mode of the deflection coil to ECP mode and observe the pattern by changing the incident angle θ of the electron beam on one crystal grain. In ECP mode, as mentioned earlier, the irradiation point on the sample 7 is moved. Since the electron beam is irradiated by changing only the incident angle without changing the angle of incidence, the crystal structure of sample 7
The amount of reflected electron signal from the irradiation beam varies depending on the incident angle of the irradiation beam. That is, when the electron beam incident angle θ satisfies the above equation, the amount of reflected electrons increases.

Therefore, if the electron beam incident angle θ is changed, the reflected electron intensity can be changed because the wavelength λ of the irradiated electron beam and the lattice spacing 2d of the sample crystal are constant. The signal is detected by a backscattered electron detector 6 (having a beam passage hole), and a video signal amplified H
The data is input to the observation CRTIO via 9. In the observation CRTIO, when general surface scanning is performed, it is synchronized with the incident angle deflection of the XY constant scanning irradiation beam on the sample surface 7, so Niletron channeling by backscattered electron signals is performed.
Pattern (E CP ; Electron Chano
elling Pattern++) is drawn and observed 0
The above is a method for obtaining a normal Niletron channeling pattern in a backscattered electron igi microscope or the like. In addition,
It is also possible to A/D convert the signal at this time and capture it in the same manner as in surface scanning, and to perform ECP analysis using the CPU II.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, constant incident angle plane scanning observation information and ECP information are A/D converted,
Since the CPU allows the observation to be performed in arbitrary levels, the crystal grain image can be clearly recognized, excluding factors affected by the device conditions and sample processing conditions. Furthermore, since the constant incident angle plane scanning observation information and ECP information can be directly taken in by the CPU, crystal structure analysis can be performed by performing calculation analysis directly on the CPU.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the system configuration of one embodiment of the present invention, and FIG.
The figure is a diagram explaining each observation mode. 1... Electron gun, 2... Converging lens, 3... Deflection coil, 4... Additional deflection coil, 5... Objective lens,
6... Backscattered electron detector, 7... Sample, 8... Deflection switching adjuster, 9... Video signal amplifier, 10... CRT for observation, 11... cpυ (central processing unit) , 12・
・・Digital scanning power supply, 13 ・・A/DI [device, 14
...Floppy disk, 15...Hard disk, 16...Console, 17...Color display, 18...Frame memory.

Claims (3)

[Claims] (1) Sample crystallinity: Analyzing the crystalline structure of a sample using an electron microscope, in which the electron beam from the electron gun is converged to the upper focal point of the objective lens using a converging lens, and the objective lens irradiates the sample surface as a parallel beam. In this tissue analysis method, an additional deflection coil is provided to scan the electron beam over the surface of the sample while maintaining a constant electron beam incidence angle in the deflection coil located between the converging lens and the objective lens. It is characterized by detecting the amount of backscattered electrons by scanning the surface of the sample with an electron beam divided into a large number of pixels with a constant electron beam incident angle, and analyzing the crystal structure of the sample by quantifying the amount of backscattered electrons. A method for analyzing the crystalline structure of a sample. (2) Claim (1) characterized in that the quantified amount of backscattered electrons is divided into levels and displayed in different colors, and the data on the amount of backscattered electrons before being digitized is displayed as a backscattered electron scanning image. A method for analyzing a sample crystalline structure described in . (3) Recognize crystal grains based on the backscattered electron scanning image obtained by scanning the surface of the sample with an electron beam while maintaining a constant electron beam incidence angle, and move the irradiation point on the sample. Claim (1) characterized in that the crystal structure is recognized based on the electron channeling pattern obtained by irradiating the electron beam by changing only the incident angle of the electron beam.
and (2).