JPS5871444A - Diffracting apparatus for electron radiation - Google Patents

Abstract

PURPOSE:To analyze and record diffraction patterns very readily, by a method wherein marks which show lengths as an angle scale are given within a CRT display which shows diffraction patterns based upon diffraction of electron radiation. CONSTITUTION:CPU22 is applied with signals such as a magnification signal for a magnification changeover means 23 and an accelerating voltage signal corresponding to an output from a high voltage power supply 12. CPU22 controls a power supply 13 for a condencer lens and other component elements based upon these signals, and applies signals to a character signal generating means 24 and a mark signal generating means 25, as well, so as to indicate marks and numerics on a display of a CRT15. In the present apparatus, a bar-mark and a number 10 overlapped on a pattern in right and lower part of CRT display, for example, show that the position being apart from the center (angle theta=0 deg.) of CRT display by a bar-marked length is at angle theta=10 deg.. Accordingly, the angle within the pattern is readily obtained, while observing the pattern, and it is very convinient for the analysis of a sample.

Description

Detailed Description of the Invention This book relates to the improvement of a device that displays electron #vA#r'' turns.There are many diffraction patterns based on electron beam diffraction using a crystalline sample.・To record and analyze it, it is necessary to know the diffraction angle in the diffraction pattern determined from the diffraction conditions.Also, to record the diffraction tf turn, it is necessary to know how many diffraction angles a certain length in the /f turn corresponds to. (It was necessary to record it at the same time, and it was quite #iW4.Instead of directly displaying or recording the diffraction-dimensional turns on a fluorescent plate or photographic plate, the present invention indirectly records them on the screen of a cathode ray tube (CRT), etc. The purpose is to facilitate the arrangement of diffraction angles for devices that display diffraction/patterns, and it is a mark that indicates the length as a scale of diffraction angles on the screen of image display means such as CRT. It is characterized by displaying.

Hereinafter, the present invention will be explained in detail based on the drawings.

! FIG. I1 is a schematic diagram showing the configuration of an embodiment of an apparatus in which the present invention is applied to a scanning electron microscope. In the figure, 1 indicates a lens barrel kept in a vacuum, and inside it, between the electron gun 2 and the sample stage 6, there are a first condenser lens 4 (not shown), a second condenser lens 5, 1st fR deflection coil 6x, 67, 2nd stage deflection coil 'Xa7ye Objective lens (final stage condenser lens) 89 Backscattered electron beam detector 9. Sample 10 etc. are stored. The acceleration voltage of the electron beam 11 generated from the electron gun 2 is varied by adjusting the high-voltage power supply 12, and the height position of the sample 10 is adjusted by adjusting the height of the sample 10.
The output of the lens power source 15.14 is adjusted to maintain the focused state of the electron beam against such changes iζ.The deflection coils 6x and 6y are set by switches. When 15 is set to 1 on 1, l is connected in series with coils 7x and 7y, and 11 is turned off.
1, lζ is the coil 6x, 6yl. The horizontal sawtooth wave signal and vertical sawtooth wave signal from the scanning power supply 16 are supplied via the variable amplifier 17. ◎The output signal of the scanning power supply 16 is a cathode ray tube (cIL'r). 1a deflection coil 19x,
Since the output of the front electron beam detector 9 is supplied to a part of the brightness modulation grid via the amplifier 20, the electron beam diffraction phenomenon l is also supplied to the tii plane. A ring/I4 turn or scanned image is displayed. Switching of the display is performed by a central control value [22] controlled by the output of the mode switching means 21. The central controller 22#c controls the magnification signal of the magnification switching means 26 for changing the amplification degree of the variable amplifier, the acceleration voltage signal corresponding to the output of the high-voltage power supply 12, and the height of the sample position by the spindle sample stage & IC. A height signal representing the height is also input, and based on these signals, the power supply 16 and switch 15 of the second condenser lens are controlled, and fζ, character signal generation means 24 and mark signal generator R25R: signals are given to the cathode ray tube. Marks and numbers as described later are displayed on the 18th picture IN.

Figure 2 shows the path of the electron beam 11 when the mode switching means 2.1 is operated in the scanning image mode. The lens principal surfaces or deflection principal surfaces of 7x and 7y are indicated by bar lines or broken lines. Sample 6J: The mouth imaged on the first stage deflection coils 6, , 67
1, when the electron beam is deflected to the left side of the paper, the second stage deflection coils 7x and 7yl deflect it back to pass through the center of the objective lens 8, so that each of the second stage deflection coils 5ζXey When a sawtooth wave current in the direction is supplied, a certain area on the sample surface is scanned by the electron beam iζ. Also, the sawtooth wave current synchronized with the scissors scanning is applied to the CRT18.
deflection coils 19x and 19yK are supplied, and the reflected electron beam generated from the sample is detected by the detector 9, and CB'I'
Since it is supplied as a brightness modulation signal of 18, CtT1
A scanned image of the sample surface rJ is displayed on the screen 8.

FIG. 3 shows that the mode switching means 21 is set to channeling mode i.
This shows the meridian of the electron @11 when the C operation is performed, and the central control value @22j causes the output current of the lens electron $15 to decrease, and the imaging position 11Pt of the crossover image by the second condenser lens 5 changes to the objective lens. As a result, the sample surface is irradiated with a parallel electron beam with a small diameter.Meanwhile, the switch 15 is turned on by the central control circuit 22, so the HR The sawtooth wave current is no longer supplied to the eye deflection coils 7 and 77, and the electron beam deflected by the first R-th deflection coil 6ζ is not returned to the center of the objective lens 8 (the axis of the objective lens magnetic field When the electron beam enters the outside and receives the refraction effect due to the lens magnetic field, it irradiates the sample 6 at an incident angle θ.If the current supplied to the R-th deflection coil changes, the incident angle of the electron beam -
Although the azimuth P changes as much as i, the excitation stiffness of the objective lens 8 is set so that the sample surface position becomes image-resistant with the deflection of giR as the object surface, so the sample irradiation position of the electron beam is always remains constant. In this way, angular scanning is performed with the electron beam on a specific minute region on the sample, and the (scanning) position within the CRT picture box corresponds to the sample incident angle t0 and azimuth tp of the electron beam, respectively.ξζ When the sample 6 has a crystal structure, the intensity of the reflected electrons increases or weakens when the electron beam is incident from a specific direction.
If1ζ is displayed as a so-called pseudo-Kikuchi turn (channeling/-size turn). FIG. 4 (al) shows the state of the CRTiii surface on which such a channeling pattern is displayed, and a bar mark and the number 10 are displayed on the lower right side superimposed on the t4 turn. This means that the position away from the center of the CRT picture area (angle 0 = θ°) by the length of the bar mark is at angle θ = 100. When performing analysis, it is extremely convenient because you can easily know the angles within the pattern.Also, after taking a photograph of the CRTiji surface (ζNo matter how you enlarge and print the photograph, the channeling pattern will not be visible). Since the angle mark is displayed inside, there is no risk of making a mistake in checking with records or making conversion calculations. The peak value of the sawtooth wave current applied to the deflection coil 6 is doubled, and the length of the channeling turn in the CB'f' image is doubled. Changes are centrally controlled M[2
2 and is monitored by the mark signal generator RIζ
Therefore, the angle display in CRTi1g is always maintained correctly because the length of the 7-ri in CRTiill is changed by 2 times 1. Also, if the length of the bar reference mark is changed in this way so as to display a constant value (1G) of the incident angle, it becomes unnecessary to display the character "1101". While keeping the height of the bar mark displayed within the plane constant, the number representing the incident angle θ corresponding to its length is set as shown in Fig. 4, 1bl.
It is possible to achieve the object of the present invention even by changing from 20 to 20.

Figure S (a) shows an example of a CRT picture box in the above-mentioned scanning image mode, and the bar mark and numbers on the lower right side indicate the reference length of the CRTij box and the length converted onto the sample, for example, 100μ ( tkl+ in FIG. 5 shows the state after switching to 2000 times. This (b1 In Figure 1, the number 10 represents 100 μ.
0 remains the same, but the length of the par mark doubles.In this way, regardless of changes in image magnification, it is necessary to display the number 100 if it always represents a constant length of 100μ on the sample. (Fig. 5 1c)
The same effect can be obtained by displaying #C like the sample (microns) represented by the bar mark while keeping the length of the bar mark constant as shown in Iζ.

By the way, if you change the accelerating voltage of the electron beam that irradiates the sample or the height position of the sample, the focal length of the electron lens and the deflection angle by the deflection coil will change, and the optical system shown in Figures 2 and 3 will also change. Therefore, due to such changes, CRTjii
Calculations for correcting discrepancies in the bar mark display and numerical display in the ffi are performed in the central control unit [22+ζ. Since a mark indicating the length is displayed as an angle scale on the CRT screen, it is possible to analyze and record diffraction-dimensional turns extremely easily. If a scanning electron microscope with a so-called micron marker function is used, CBT
Since the means for displaying the mark on the m-plane can be shared, just by providing a slight additional means, the book@mei can be converted to IJ.
! It becomes possible to apply

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an apparatus according to one embodiment of the present invention, FIGS. 2 and 3 are schematic diagrams respectively showing the electron optical system in the apparatus of FIG. 1, and FIGS. It is a schematic diagram for explaining the operation of the device. 2: Electron gun, 6: Sample stage, 4: First condenser lens, 5: 5% 2 condenser lens, 6x, 6y:
@1st stage deflection coil, 7x, 7y: 2nd f & deflection coil,
8: objective lens, 9: backscattered electron beam detector, 10: material,
11: Electron beam, 12: High voltage power supply, 16.14: Lens power supply, 15: Switch, 16: Scanning power supply, 17: Variable amplifier, 21: Scanning mode switching means, 22: Central control device, 26: Magnification switching means, 24: Character signal generation means, 25
: Mark signal generation means. (a) (b) (c) Fourth
Diagram (Q) (b) (C) S diagram

Claims (1)

[Scope of Claims] L In a diffraction device that indirectly displays diffraction patterns based on electron beam diffraction by a deliverable sample on an image display means, a length is displayed as an angle scale in a display frame of the image display means. An electron beam diffraction apparatus characterized in that it is provided with a means for displaying a mark indicating that -ik! When the incident angle θ and the azimuth angle − of the electron beam are lifted by the angle IIL using the deflection means, the synchronized signals are supplied to the angle sweep within #CC. jif of the Fii44a display means
A device g configured to use a detection signal obtained from the sample as a IIIL modulation signal: a mark indicating a length on the screen of the image display means #i, and a hook corresponding to the length of the mark; An electronic 4IIgl folding device, characterized in that it is provided with means for displaying numbers or symbols representing the incident angle and the value of 0.