KR100833647B1 - Spectrometer for high energy charged particle - Google Patents

Abstract

A spectrometer for high energy charged particle is provided to realize a spectrum of which the limit of resolution is improved by detecting a not only a second charged particle in a low energy region but also a second charged particle in a high energy region. A second charged particle is incident into a mesh electrode. A cylindrical electrostatic lens electrode is interlocked with the mesh electrode. The cylindrical electrostatic lens electrode is comprised of a first electrode(104), a second electrode(106), a third electrode(108), a fourth electrode(110), and a fifth electrode(112). A first image plane passes through the second electrode and has an opening to which the second charged particle passes. A second image plane passes through the fourth electrode with an opening to which the second charged particle passes. The second charged particle having high energy is focused and analyzed. An energy analyzer distributes the second charged particle according to energy. An electron circuit system acquires a spectrum or an image of the second charged particle passing through the energy analyzer.

Description

Spectrometer for high energy charged particle}

1 is a block diagram of a conventional charged particle spectrometer,

2 is a configuration diagram for obtaining an angular distribution of the emitted particles by the charged particle focusing lens according to the present invention;

3 is a computer simulation state diagram of the angle distribution according to the configuration of FIG.

4 is a configuration diagram for obtaining an image distribution of the emitted particles by the charged particle focusing lens according to the present invention;

5 is a computer simulation state diagram of the image distribution according to the configuration of FIG. 4;

6 shows a block diagram of the high energy charged particle spectrometer of the present invention.

<Description of the symbols for the main parts of the drawings>

10: Sample 11: Slit

12: first lens adjuster 14: second lens adjuster

16a, 16b, 16c: electrostatic lens 18a, 18b: aperture

20: detector 32: outer hemisphere

34: inner hemisphere 36: channeltron

38: mounting plate 40: first retard

42: output lens 44: second retard

102: mesh electrode 104: first electrode

106: second electrode 108: third electrode

110: fourth electrode 112: fifth electrode

120: first image plane 122: second image plane

124: first diffraction plane 126: second diffraction plane

130: microchannel plate 140: position detector

150: spectrum control unit 160: data system

170: electrostatic lens power supply

The present invention relates to a high energy charged particle spectrometer and a method of use, and more particularly, in a spectrometer for analyzing a sample using photoelectrons emitted when a beam is scanned on a sample, the particles emitted from the sample (2 The present invention relates to a charged particle analyzer capable of analyzing not only charged particles in a low energy region, but also charged particles having a high energy of 10 keV or more and maintaining a wide scattering angle distribution.

Charged particle spectrometer technology used in surface science is a method of properly examining the surface and interface information of the sample to analyze the energy of secondary charged particles emitted from the sample by bombarding the surface of the sample with X-rays, ultraviolet rays, electron beams, and ion beams. This is a technique to find the chemical components, density and crystallinity of the surface and the interface.

Charged particle spectrometer technology uses both a charged particle spectrometer and a microscope simultaneously, and conventional charged particle spectrometers produce emitted secondary charged particle images of sample surfaces and interfaces with specific energy in the electric field. Charged particles of various energy ranges pass through the charged particle spectrometer to produce spectra with specific energies, and obtain characteristic information on the surface and interface of structural and chemical samples from charged particle images and spectra.

1 shows a configuration of a conventional charged particle spectrometer.

The conventional charged particle spectrometer is largely composed of an energy analyzer and an electrostatic lens system. The hemispherical energy analyzer of the energy analyzer is provided on the mounting plate 38, the outer hemisphere 32, the inner hemisphere 34, the channeltron 36. A first retard 40, an output lens 42, a second retard 44, and a detector (not shown) are sequentially connected to one side of the channeltron 36, and an electrostatic lens system is mounted on the other side thereof.

The electrostatic lens system includes first and second lens adjusters 12 and 14 and a plurality of electrostatic lenses 16a, 16b, and 16c, and a slit 11 is provided on the sides close to the apertures 18a and 18b and the sample. have.

The energy analyzer is hemispherical, the outer hemisphere 32 and the inner hemisphere 34 become electrodes, and the charged particles are dispersed according to their energy due to the electric field generated between the two electrodes. At this time, the path of the dispersed charged particles depends on the kinetic energy of the charged particles. Due to the energy dispersion in the energy analyzer, the image is dispersed and the spatial characteristics of the image are not discerned along the energy dispersion axis. Therefore, the sample is mechanically appropriately obtained to obtain a two-dimensional image.

The position detector can be used to obtain energy spectra and two-dimensional images of each sample of the sample for the slit.

The method of obtaining the structure and chemical information of the surface and interface of the sample using the charged particle spectrometer having the above structure is as follows.

The primary particle generator (not shown) is irradiated to the sample, and scattered secondary charged particles are made to enter the electrostatic lens system through the slit. Secondary charged particles enter the energy analyzer through the electrostatic lens system and pass through the energy analyzer to obtain structural and chemical information about the sample.

However, since the method using a spectrometer equipped with such an electrostatic lens system is used to analyze secondary charged particles in a low energy region, especially low energy photoelectrons or secondary electrons, high energy secondary charged particles of 10 keV or more are analyzed. There is a problem that the high-energy secondary charged particles above 10keV have to analyze a separate method.

The present invention has been made to solve the above problems, and an object of the present invention is to detect secondary charged particles in a high energy region of 10 keV or more as well as secondary charged particles in a low energy region among secondary charged particles emitted from a sample, and In the detection of energy secondary charged particles, -20 ° to 20 °, which is a conventional scattering angle, is maintained, and a high energy charged particle spectrometer capable of obtaining a spectrum with improved resolution by detecting secondary charged particles in a high energy range is provided. There is.

As a means for achieving the above object, the present invention is a spectrometer for analyzing the secondary charged particles emitted from the sample by irradiating the primary incidence on the sample, the mesh electrode 102 to which the secondary charged particles are incident; And a first electrode 104, a second electrode 106, a third electrode 108, a fourth electrode 110, and a fifth electrode 112 interlocked with the mesh electrode and to which a voltage is applied from the outside. And a cylindrical electrostatic lens system comprising a cylindrical electrostatic lens electrode; and having a first image plane penetrating through the second electrode and having an opening having a predetermined size, and having an opening having a predetermined size. It provides a high-energy charged particle spectrometer, characterized in that the two image plane is formed, and the secondary charged particles having a high energy is focused by analyzing without aberration.

The high energy charged particle spectrometer includes an energy analyzer connected to the electrostatic lens system to disperse secondary charged particles according to energy; And an electronic circuit system for obtaining a spectrum or an image of the secondary charged particles passing through the energy analyzer.

The electronic circuit system includes a microchannel plate 130 for amplifying a signal of secondary charged particles; A position detector 140 for detecting a position of a signal on the microchannel plate 130; Spectrum control unit 150; And a data system 160.

Hereinafter, with reference to the accompanying drawings looks at the structure of the high energy charged particle spectrometer of the present invention as a preferred embodiment.

2 is a cross-sectional view showing the structure of the electrostatic lens system of the high-energy charged particle spectrometer of the present invention. As shown in Figure 2, the electrostatic lens system serves to focus the charged particles. The electrostatic lens system is composed of a mesh electrode 102 and cylindrical electrostatic lens electrodes 104, 106, 108, 110, 112 in which a plurality of electrodes are formed. In addition, the first image plane 120 and the second image plane 122 are positioned so that the scattered secondary charged particles are focused at one point.

The mesh electrode 102 has a mesh structure, and is provided to eliminate aberrations that may occur when focusing secondary charged particles because the electrode is formed in a cylindrical shape.

The cylindrical electrostatic lens electrode is composed of the first to fifth electrodes 104, 106, 108, 110, 112, a high pressure is applied to analyze the high-energy secondary charged particles.

The first image plane 120 has an opening for limiting the region so that only particles of a certain region of the scattered secondary charged particles pass. In addition, an opening for limiting an area may be provided in the second image plane 122 to adjust the distribution angle of the secondary charged particles.

The voltage at the fifth electrode of the cylindrical electrostatic lens electrode is controlled to adjust the angular distribution of the secondary charged particles incident to the energy analyzer.

The energy analyzer is for the analysis of the secondary charged particles passing through the electrostatic lens system, of which hemispherical electrostatic energy analyzer is preferably used, but is not limited thereto.

The hemispherical electrostatic energy analyzer is formed with an outer hemisphere 32 and an inner hemisphere 34 provided on a mounting plate. Voltage is applied to the outer hemisphere 32 so that the path of the secondary charged particles incident to the energy analyzer is formed along the hemisphere, and a voltage opposite to the outer hemisphere 32 is applied to the inner hemisphere 34. The secondary charged particles incident on the electrostatic energy analyzer are dispersed according to the energy of the secondary charged particles due to the electric field between the outer hemisphere 32 and the inner hemisphere 34.

The electronic circuit system includes a microchannel plate 130, a position detector 140, a spectrum control unit 150, and a data system 160.

The microchannel plate 130 serves to amplify the signal of the secondary charged particles passing through the energy analyzer and is installed at the end of the secondary charged particles emitted from the energy analyzer.

The position detector 140 detects a position of a signal on the microchannel plate 130.

The spectrum control unit 150 is responsible for electronic control and high voltage supply to the spectrometer.

Data system 160 enables spectrum and image acquisition at a computer (personal computer).

The electrostatic lens power supply 170 is connected to the electrostatic lens system to apply a voltage to the cylindrical electrostatic lens electrode consisting of a mesh electrode and the first electrode and the fifth electrode, and focuses secondary charged particles having energy of 10 keV or more. If desired, relatively high pressure is applied.

Hereinafter, an embodiment for obtaining a spectrum and an image of secondary charged particles using the high energy charged particle spectrometer of the present invention will be described.

<Acquisition of Energy Spectrum According to Angle Distribution>

A spectrometer including an electrostatic lens system configured as shown in FIG. 2 is installed as shown in FIG. 4. The voltage applied to each electrode of the electrostatic lens system is 0 V for the mesh electrode 102, 30 kV for the first electrode 104, 85 kV for the second electrode 106, 0 kV for the third electrode 108, and 80 kV is applied to the four electrodes 110, 20 kV is applied to the fifth electrode 112, and the particles irradiated to the sample are protons having an energy of 100 keV.

Under the above conditions, the trajectory of the secondary charged particles passing through the electrostatic lens system is shown in FIG. 3. Looking at Figure 3 it can be seen that there is no aberration in the electrostatic lens system.

<Secondary charged particles of  Image Acquisition>

A spectrometer including an electrostatic lens system configured as shown in FIG. 2 is installed as shown in FIG. 4. Unlike the electrostatic lens system shown in FIG. 2, the positions of the first diffraction plane 124 and the second diffraction plane 126 having openings having a predetermined size are slightly varied.

The secondary charged particles emitted from the sample pass only secondary charged particles incident in parallel to the central axis of the electrostatic lens system due to the opening of the first diffraction plane 124, and the opening and the fifth electrode of the second diffraction plane 126. The voltage applied to limits the range of secondary charged particles incident on the energy analyzer.

Even when an image of secondary charged particles is obtained, the voltage applied to each electrode is 0 V for the mesh electrode, 30 kV for the first electrode, 85 kV for the second electrode, 0 kV for the third electrode, and 80 kV for the fourth electrode. Is applied to the 5th electrode and 20 kV, and when the particle irradiated to the sample is a proton having an energy of 100 keV, the trajectory of the secondary charged particles is as shown in FIG. Also in this case, it can be confirmed that there is no aberration of the electrostatic lens system.

In the present invention, more preferably, the position of the first image plane 120 and the second image plane 122 is not changed, and two image planes are added as shown in FIGS. The position of the opening plane can be fixed. This is because adjusting the size of the openings of the respective image planes according to the purpose of measuring the configuration as described above can reduce errors that may occur in installation.

As described above, according to the present invention, the secondary charged particles of the low energy region as well as the secondary charged particles of the low energy region of the secondary charged particles emitted from the sample by adjusting the configuration of the electrostatic lens system and the voltage applied to the first to fifth electrodes are simultaneously simultaneously displayed. Detecting the charged particles can contribute to saving time and cost, and also has the advantage of obtaining a spectrum with improved resolution by detecting secondary charged particles in the high energy region.

Therefore, since information such as chemical composition, density, and crystal on the surface of the sample can be obtained more accurately and quickly, there is an advantage that can contribute to quality improvement in the field using spectrometer such as semiconductor sample inspection.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it will be readily apparent to those skilled in the art that various other modifications and variations are possible without departing from the spirit and scope of the invention. Are all within the scope of the appended claims.

Claims (3)

In the spectrometer for investigating the primary incidence to the sample to analyze the secondary charged particles emitted from the sample, A mesh electrode 102 to which the secondary charged particles are incident; And The first electrode 104, the second electrode 106, the third electrode 108, the fourth electrode 110, and the fifth electrode 112 interlocked with the mesh electrode and to which a voltage is applied from the outside. A cylindrical electrostatic lens electrode; and A first image plane passing through the second electrode 106 and having an opening through which the secondary charged particles can pass; And a second image plane penetrating the fourth electrode 110 and having an opening through which the secondary charged particles can pass. A high energy charged particle spectrometer, characterized in that the secondary charged particles having a high energy is analyzed by focusing without aberration. The method of claim 1, An energy analyzer connected to the electrostatic lens system to disperse the secondary charged particles according to energy; And An electronic circuit system for obtaining a spectrum or an image of the secondary charged particles passed through the energy analyzer, characterized in that it further comprises. The method of claim 2, The electronic circuit system A microchannel plate (130) for amplifying the signal of the secondary charged particles; A position detector (140) for detecting a position of a signal on the microchannel plate (130); A spectrum control unit 150 for controlling the spectrometer and supplying a high voltage; And A high energy charged particle spectrometer, comprising: a data system 160 for enabling spectrum and image acquisition in a computer.

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