JPS6066174A - Method and device for detecting electron and ion superposed beam - Google Patents

Abstract

PURPOSE:To separate an ion and an electron and to detect them simultaneously by detecting the ion utilizing a magnetic field deflecting property of a charged particle, and detecting the electron utilizing a transmitting and light emitting property in a substance of the charged particle. CONSTITUTION:(1) A transmitting property into a substance of a charged particle. (2) A mass dependability of a light emitting efficiency. (3) A mass dependability in a magnetic field deflection. The detection is executed by utilizing said three phenomena. That is to say, in case a scintillator is utilized as a detector, only an electron is contributed to transmission and light emission by the phenomenon of (1). Even if a light emission by excitation of an ion occurs, it can be made extremely smaller than a light emission of the elctron by an effect of (2). Also, when detecting the ion, the ion is discriminated from the electron and detected by utilizing an effect of (3), namely, a magnetic field polarization. In this way, the electron and the ion are separated and can be detected simultaneously.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is applicable, for example, to the field of measurement, particularly to the combination of secondary ion mass spectrometry, which is a high-sensitivity analysis method, and electron microscopy, which is a high-resolution subassembly β method. The present invention relates to a method and apparatus for detecting a superimposed beam 11 of electrons and ions, which is an essential means.

[Prior art]

Conventionally, methods such as those shown in FIG. 1 and FIG. 2 have been adopted as charged particle detection methods. Figure 1 shows a detection system that combines a scintillator 4 and a photomultiplier tube 6.The principle of operation is that charged particles are first received by the scintillator and converted into light, and the light output is converted into light with high electron multiplication. The purpose is to amplify and detect using a tube. When ion beam 1 and electron beam 2 are simultaneously incident on this detector, the emission efficiency of ions and electrons in the scintillator is different, so in reality,
It will work as a detector for electrons only. In other words, it is difficult to detect only ions. This shows a conventional example in which a secondary electron multiplier tube 7 is used even if ions and electrons can be detected simultaneously. In this case, both ions and electrons can be detected, but it is difficult to distinguish and detect both signals independently.

As described above, conventional detection methods have the drawback that it is difficult to detect electrons and ions simultaneously.

[Object 1-1 of the invention] An object of the present invention is to provide a detection method and device that can independently and quantitatively detect changes in the intensity of n·1 B 11 before ion/electron superposition. be.

[Wave type of invention]

The present invention utilizes the following three phenomena.

1) Permeability of charged particles into substances 2) Mass dependence of luminous efficiency 3) Mass dependence of magnetic field deflection, that is, when a scintillator is used as a detector, 1
) By adjusting the thickness of the conductive layer on the surface of the scintillator appropriately, only electrons contribute to transmitted light emission. Even if there is light emission due to ion excitation, 2)
Due to this effect, the light emission can be made extremely small compared to the emission of electrons. Ion detection utilizes the effect of 3), that is, magnetic field deflection, to distinguish ions from electrons and detect them. In this way, detection of the electron/ion component P7I in the ion/electron superimposed beam is realized.

An example will be shown in which the present invention is applied to a three-dimensional M-folding method in a small area. FIG. 3 shows the construction of J-no-Kero-11Vi as an example.

The device has a combined configuration that includes an ion microanalyzer and an electron microscope function.

- This device mainly consists of a primary irradiation system, namely a charged particle source 10, a focusing deflection system 11. Sample chamber 12, sample 1
3. Sector electrode N415 for secondary ion and electron deflection, scintillator with a metal film attached to the surface 19. Shield mesh] 7, photomultiplier tube 1G, electronic housing 11 Ogawa CR
T22, sector magnetic field 18, IA detection +t:Y 21
Consisting of CRT 23 for J, 'i and ion image wAQ
are doing,.

The operating principle is as follows. A Duo Plasma 1-ron was used as the positive and negative charging source 1O.

This charged particle source is of a plasma type, and when an extraction voltage is applied to extract negative ions, negative ions and electrons 14 are generated at the same time.
released from the source. When a negative high voltage is applied to the sample in this state, negative secondary ions 1 and secondary electrons 2 are simultaneously emitted from the sample due to a sputtering phenomenon. These ions 1
The electrons 2 follow the trajectory shown in the figure due to the sector electric field 15, some of which strike the scintillator 19, and some of which pass through the center hole of the scintillator 19 and are introduced into the sector magnetic field 18. The ions 1 that hit the scintillator J9 are absorbed by the metal film on the surface of the scintillator, making it difficult to illuminate the scintillator 19. On the other hand, the electrons 2 striking the scintillator 19 cause the scintillator 1g to glow due to its transparency. The light 20 generated by the electrons thus generated is received by a photomultiplier tube 16, and the output thereof is a C for electron image observation.
It is used as a brightness modulation signal for RT22.

On the other hand, the ion beam 1 that has passed through the center hole of the scintillator 19 is introduced into the sector magnetic field 18, and after mass separation is detected as a specific ion by the ion detector 21. This output is used as a brightness modulation signal for the CRT 23 for detecting secondary ion images, and is used as a two-dimensional original image as a secondary ion image.

In this embodiment, the -order charged particle beam 1114 is transferred to the CRT 22.
．． By scanning in synchronization with the deflection of 23, we succeeded in observing the scanning type 4th ion image and secondary electron image as independent images. In this case, the -order electron heat 11 and other ion beams are each focused in a direction of 41 s by a combination of a magnetic field lens and an electric field lens (omitted), and the beam diameter on the sample is
1μm and 0.05μ for ion and electron beams, respectively
It is about m. That is, by using electrons, it was possible to observe the shape of the sample surface with an image resolution of 0.05μ or less, and dynamically analyze changes in the mass spectrum and specific secondary ion characteristics that accompany changes in the shape.

As described above, by using the electrician/ion superimposed beam detection method of the present invention, it is possible to observe the three-dimensional morphology of the sample and dynamically obtain elemental distribution information corresponding to each surface at a convenient time, allowing multidimensional evaluation of the sample. (characterization)
is now possible.

〔Effect of the invention〕

The effects of the present invention are as follows.

(2) Even when ions and electrons are superimposed on the signal system, both can be detected independently. This provides more reliable information.

2) By utilizing the present invention, three-dimensional tA observation can be achieved by utilizing the etching action and microanalysis ability of the ion beam (secondary ion mass spectrometry) and the microscopic observation ability of the electron beam (electron microscopy). Simultaneously and continuously analyze the three-dimensional element concentration distribution and three-dimensional element concentration distribution, making it possible to perform multidimensional evaluation (characterization) of substances.

[Brief explanation of drawings]

1 and 2 are principle diagrams showing a conventional detection method, and FIG. 3 is a principle diagram showing an embodiment of the present invention. Explanation of symbols

Claims (1)

[Claims] ■ Detecting ions using magnetic field deflection properties of charged particles;
A method for detecting an electron/ion superimposed beam, which is characterized by detecting electrons by utilizing the transmissive luminescence properties of charged particles within a substance. a scintillator that receives a superimposed beam of electrons and ions, a means for detecting light generated by the scintillator due to electrons in the beam, and a magnetic field polarizing means for introducing the beam that has passed through a hole in the scintillator. , means for detecting ions in the beam separated by the magnetic field deflecting means.