JPH07335159A - Intensity damping mechanism of electron microscope with electronic spectrometer - Google Patents

Abstract

PURPOSE:To prevent incidence of an electron beam from exceeding a measurable limit onto an image sensing device by deflecting the electron beam at certain periods using deflecting means in an electron spectrometer. CONSTITUTION:An electron beam 2 is deflected at certain periods by deflecting means 9a, 9b in an electron spectrometer 8. The deflecting means 9a, 9b are operated so that the spectral image does not move on an image sensing device 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission electron microscope equipped with an electron spectroscope and a material evaluation and analysis mechanism using the same.

[0002]

2. Description of the Related Art Conventionally, in a transmission electron microscope equipped with an electron spectroscope and an image detection device, means for attenuating the electron beam intensity of an incident image for the purpose of protecting the image detection device and quantitative image detection. For example, there was a parallel detector with a variable attenuator (USP 4,831,255). However, in this method, a deflecting means is installed immediately before the image detecting device to deflect the electron beam, and it cannot be applied to a two-dimensional image.

[0003]

In a transmission electron microscope equipped with an electron spectroscope, when an image having an electron beam intensity exceeding the measurement limit is incident on the image detecting device, the image cannot be detected. In addition to this, there were problems such as failure of the image detector or partial damage.
As a conventional technique, there is a parallel detector with a variable attenuator, but since this method scans an image on an image detection device,
The image vibrated on the detector and a two-dimensional image could not be taken correctly.

[0004]

SUMMARY OF THE INVENTION The present invention is directed to a transmission electron microscope, an electron spectroscope installed therein, a deflecting means provided in the electron spectroscope, and driving the deflecting means to drive its waveform, frequency and amplitude. A control device for controlling the above, an energy slit for selecting an electron beam having a specific energy after being dispersed, and an image detecting device for recording and detecting the electron microscope image after being selected.

[0005]

In the present invention, the deflection means provided in the electron spectroscope deflects the electron beam by controlling the waveform, frequency and amplitude of the deflection operation by the control device. The electron spectroscope separates the electron beam by the difference in energy of the electron beam. The energy slit selects an electron beam having a specific energy by transmitting only an electron beam at a specific position among the split electron beams. The electron microscope image by the selected electron beam is detected by the image detector.

[0006]

Embodiments will be described below with reference to the drawings.
FIG. 1 shows an overall view of the present invention. 1 is a transmission electron microscope, 2 is an electron beam, 3 is a converging lens, 4 is a sample,
Reference numeral 5 is an objective lens, 6 is an image forming lens system, 7 is a fluorescent plate, 8 is an electron spectroscope, 9a and 9b are deflecting means, 10 is an energy slit, 11 is a distortion correcting lens system, and 12 is an image detecting device.

After being converged by the converging lens 3, the electron beam 2 is incident on a target portion of the sample 4. The electron beam transmitted through the sample 4 is magnified by the objective lens 5 and the imaging lens system 6 to form an image on the fluorescent plate 7. Fluorescent plate 7
When is shifted from the optical axis, the electron beam 2 enters the electron spectroscope 8 and takes different trajectories depending on the difference in energy. The figure shows a trajectory 13a of a specific energy. At this time, the point 14a most converged by the final lens of the imaging lens system
(Crossover) is the object point of the electron spectroscope, and the position of the energy slit 10 is the image point 14b. Therefore, the crossover 14a normally causes energy dispersion in the radial direction (x direction) by an electron spectroscope, and when the energy is constant, it becomes almost a point to form linear spectra 14b and 14b 'on the energy slit. . In reality, it is difficult to completely converge as a point in the Y direction, so that a band-shaped spectrum slightly spread in the Y direction is obtained. The energy slits are parallel to the Y direction to select a specific energy. The electron beam 13a having a specific energy selected by the energy slit is subjected to image distortion and focus correction by the distortion correction lens system 11, and then detected and recorded as a two-dimensional image by the image detection device 12.

In the present invention, when a plurality of deflecting means such as the electron beam deflecting means 9a and 9b installed in the electron spectroscope are combined and the electron beam is deflected, the trajectory of 13b is traced to form an image of the electron beam. It is controlled so as not to move on the image detection device 12. The waveform, frequency, and amplitude are controlled by the controller. The deflected direction is the radial direction (X direction) of the electron spectrometer, and is perpendicular to the direction of the energy slit. When deflected, the electron beam is blocked because of the presence of energy slits on the electron path. By performing this deflection operation periodically, only a certain proportion of the electron beam reaches the image detection device, and the intensity further changes.
Changes in the image due to deflection will not be visible on the detector. As a result, an electron beam intensity attenuation mechanism can be provided.

FIG. 2 shows a conventional embodiment.
Conventionally, the deflection means 16 is provided before the line-shaped electron beam detector 17.
a is provided and the power source 16b periodically deflects. As a result, the energy spectrum 15 is detected only when it crosses the line-shaped electron beam detector and when it crosses over the device, so that it is possible to observe only a part of the intensity. This is effective when detecting the intensity of a line-shaped image, but when detecting a two-dimensional image, only an image with blur in the lateral direction (Y direction) can be obtained.

FIG. 3 is a diagram for explaining an example of changing the waveform of a signal (for example, a voltage value) for controlling deflection in the control method of the deflection means. 18a is a waveform before changing, and 18b is a waveform after changing. The case where the electron beam reaches the image detection apparatus is indicated by L when it does not reach H. By changing the waveform in this way, the electron dose reaching the image detection device can be changed.

[0011]

According to the present invention, there is provided a protection function when an electron beam having an electron dose larger than the measurable electron dose enters the image detecting device during observation of the transmission electron microscope. Further, by changing the waveform, it is possible to change the actual measurement time and perform the measurement, which enables quantitative measurement.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a conventional example.

FIG. 3 is a waveform diagram of an operation for deflecting.

[Explanation of symbols]

1 ... Transmission electron microscope, 2 ... Electron beam, 3 ... Converging lens,
4 ... Sample, 5 ... Objective lens, 6 ... Imaging lens system, 7 ... Fluorescent plate, 8 ... Electron spectroscope, 9a, 9b ... Deflection means, 10 ...
Energy slit, 11 ... Distortion correction lens system, 12 ... Image detection device.

Claims (4)

[Claims] 1. An electron spectroscope, an energy slit for selecting a part of an electron beam split by the electron spectroscope, and an image detection device for detecting an electron microscope image by electrons selected by the energy slit. An intensity attenuation mechanism of an electron microscope with an electron spectroscope, characterized in that, in the transmission electron microscope provided, a deflection means that operates periodically is provided in the electron spectroscope. 2. The intensity attenuating mechanism of an electron microscope with an electron spectroscope according to claim 1, wherein the deflecting means deflects an image so as not to move on the image detecting device. 3. The intensity attenuation mechanism of an electron microscope with an electron spectroscope according to claim 1, 2 or 3, wherein the waveform, frequency and amplitude of the deflection means can be changed. 4. The intensity attenuating mechanism of an electron microscope with an electron spectroscope according to claim 1, wherein a deflection direction of the deflection means is a radial direction of the electron spectroscope.