JP2005127967A - High resolution/chemical bond electron/secondary ion microscope apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new microscope with the option of a signal source having a large strength enough to grasp a chemical bond by eliminating aberration to improve resolution. <P>SOLUTION: A wavelength of an electromagnetic wave is fixed to a predetermined wavelength having chemical information at the absorbing end of a sample by an angle modulating part 15. A focus location of an imaging optical system 13 is changed by a focus location modulating part 16 at a high speed. Effects of spherical aberration and chromatic aberration of the imaging optical system 13 are eliminated. Obtained image information is free from aberration. Information on a chemical bond state of a surface of the sample is obtained by analyzing an X-ray absorbing fine structure (XAFS) included in the image information by an image processing part 18. An image is obtained which has substantially no aberration and has the improved resolution. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to photoelectrons, secondary electrons (including Auger electrons), or secondary ions emitted from a sample by irradiating the observation sample with a short wavelength high-intensity electromagnetic wave, an electron beam or a charged particle beam as an example. This is related to an electron / secondary ion microscope (for example, a photoelectron microscope) that observes an observation sample through an imaging optical system, and the signal intensity is increased by using an X-ray absorption fine structure (XAFS, particularly XANES or NEXAFS). The present invention relates to an electron / secondary ion microscope that improves resolution by removing spherical aberration and chromatic aberration of an imaging optical system.

  In recent years, various microscopes and analysis methods have been developed for surface nano-characterization for observing a very fine form of a sample. As typical examples thereof, for example, as shown in FIG. 7, a scanning electron microscope (SEM) and a scanning probe microscope (SPM) mainly used for observing, evaluating and analyzing the form of a sample, Scanning Auger electron microscope (AEM), secondary ion mass spectrometry (SIMS) and analytical electron microscope, mainly used for elemental analysis, transmission electron microscope (TEM), mainly used for crystal structure analysis, and Examples thereof include X-ray photoelectron spectroscopy (XPS), a scanning photoelectron microscope, and a synchrotron radiation photoelectron microscope that are used for analyzing the electronic state of a substance. Note that a scanning photoelectron microscope, a synchrotron radiation photoelectron microscope, and the like are forms of a secondary ion microscope.

  The analysis scale (resolution) of these microscopes and the like is about several nm for SEM and about 1 nm to 0.1 nm for SPM, as shown on the horizontal axis of FIG. Further, it is about several tens to 10 nm for AEM and SIMS, and several nm for an analytical electron microscope. Moreover, TEM is about several nm like SEM and an analytical electron microscope.

  However, the XPS analysis scale is around 10 μm, about several hundreds of nanometers for scanning photoelectron microscopes, and several tens of nanometers for synchrotron photoelectron microscopes. (Including a microscope), the resolution is clearly lower than that of a normal electron microscope. On the other hand, the electron / secondary ion microscope has high surface sensitivity and is useful for observing the electronic state of the nanomaterial.

  Here, it is conventionally known that the resolution of the imaging optical device can be increased, that is, the resolution can be increased by removing the spherical aberration and chromatic aberration of the imaging optical system. For example, in Patent Document 1 and Non-Patent Documents 1 and 2, a high-resolution observation image having no spherical aberration or chromatic aberration is acquired using a real-time focal position modulation spherical aberration removal method (real-time spherical aberration correction method). An imaging optical device is disclosed. According to this, it is possible to develop an electron microscope or the like that can remove the influence of spherical aberration (rotation invariant wavefront aberration) and chromatic aberration included in the imaging optical system and reproduce an image with high resolving power. As a result, it has succeeded in obtaining an atomic image from which artifacts due to spherical aberration are removed by observing an aberration-free electron microscope image. Non-Patent Documents 3 and 4 describe that spherical aberration and chromatic aberration can be removed by adjusting the electron trajectory of the electron optical system.

  By the way, a low energy electron microscope (LEEM) and a photoelectron microscope (PEEM) are known as one of the electron microscopes that project an image. LEEM and PEEM are both electron microscopes capable of obtaining an electron image in a low energy region, and the basic configuration thereof is the same. Therefore, a composite apparatus that combines these has also been developed.

  The LEEM and PEEM will be specifically described. First, an electron beam emitted from an electron gun is accelerated by a deflecting magnet (deflecting means) and vertically incident on a sample. At this time, the incident electrons are rapidly decelerated immediately before the sample. The incident electrons interact with the sample, are elastically scattered, are emitted from the sample as reflected electron beams, and are rapidly accelerated by an accelerating electric field. The accelerated reflected electron beam is deflected and magnified by an objective lens (objective optical system), a deflecting magnet, and an imaging lens (image forming optical system) to form an electronic image. This electronic image is amplified and fluorescent plate (screen means) ) Is imaged on top. At this time, as in the electron microscope, it is possible to obtain a bright field image that expands the reflected electron beam of the (00) spot or a dark field image that expands the diffraction spot. This image is a LEEM image.

  On the other hand, in the above configuration, when a photon (photon) is incident on the sample instead of the incident electron beam, a photoelectron image can be formed. This image is a PEEM image.

  In LEEM and PEEM, (1) it is a projection electron microscope, (2) there is no clogging in the resulting image (because it uses electrons emitted perpendicular to the sample), (3) mean free path Because it uses short low-energy electrons, information near the surface can be obtained. (4) Surface phenomena can be observed in real time (video rate). (5) High temperature (about 1770 K) to low temperature. It has features and advantages such as being able to easily observe a sample up to (liquid nitrogen temperature) in real time.

  In particular, with respect to PEEM, (1) a high-resolution image of X-ray photoelectron spectroscopy (XPS) can be obtained by using a high-intensity light source such as synchrotron radiation, and (2) X-rays utilizing circularly polarized light of synchrotron radiation When time circular dichroism (XMCD) is used, the magnetic domain structure can be observed, and the magnetic moment can be obtained separately for electron spin and airway angular momentum.

Regarding LEEM and PEEM, for example, there are reviews such as Non-Patent Documents 5 and 6 written by the present inventors.
JP 2003-131138 (Publication date: May 8, 2003) T. Ikuta: J. Electron Microsc. 38, 415 (1989) Y. Takai et al .: J. Electron Microsc. 48, 879 (1999) H. Rose, P. Hartel and D. Preikszas, Proc. Of 3rd International Symposium on Atomic Level Characterizations for New Materials and Devices, (Japan Society for the Promotion of Science 141 Committee, Nov. 2001) pp 161-166 D. Preikszas and H. Rose, J. Electron Microscopy, Vol. 46, 1-9 (1997) Koshikawa Takanori: Surface Science Vol.23, No.5, 262-270 (2002) Takanori Koshikawa, Tsuneo Yasue: Materia No. 41, No. 12, Special Feature “Frontiers in Evaluation of Advanced Materials by Various Microscopy”, separate volume 884-885 (2002)

  However, the real-time focal position modulation spherical aberration removing method used for the electron microscope cannot be used for PEEM as it is, and therefore it is difficult to sufficiently improve the resolution in PEEM.

  Specifically, unlike a general electron microscope, PEEM irradiates a sample with a photon to image photoelectrons emitted by inner shell excitation. Here, if the excitation cross section of the electromagnetic wave (radiated light) used for the inner shell excitation is small, the signal intensity of the photoelectron becomes weak. Therefore, if spherical aberration and chromatic aberration are removed from the obtained photoelectron image in real time to improve the resolution of the photoelectron microscope, it is necessary to use very strong electromagnetic waves (radiated light). However, since the intensity of the emitted light used is limited, it is difficult to obtain photoelectrons having a sufficient signal intensity.

  For this reason, when removing spherical aberration and chromatic aberration in PEEM, the real-time focal position modulation spherical aberration removing method cannot be applied as it is. Therefore, it is difficult to improve the resolution of PEEM using this method.

  However, in an image obtained by taking means for removing spherical aberration and chromatic aberration, when trying to acquire a high-speed signal, the signal intensity is not sufficient, making it difficult to acquire a high-speed signal. On the other hand, synchrotron radiation that is widely used now is attracting attention as a revolutionary light source that provides high-intensity excitation light. However, even with this light source, the brightness is still not sufficient. And understanding chemical bonds is a very important issue. There is a long-awaited microscope that satisfies many of these requirements.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a new microscope in which a resolution is improved by removing aberrations and a signal source having a high intensity that can be understood by chemical bonds is selected. .

  As a result of intensive investigations in view of the above problems, the present inventors have found that low-energy photoelectrons and second-orders are obtained in a technique for removing spherical aberration and chromatic aberration, such as a photoelectron microscope, and an X-ray absorption fine structure (XAFS, in particular, XANES or NEXAFS). By simultaneously using a technique that increases the signal intensity by using electrons (using the sample current also has the same effect), a high-resolution image with high resolution and chemical bond information is close to real time. The present inventors have found that imaging is possible and have completed the present invention.

  In other words, if low-energy photoelectrons and secondary electrons are used as the signal source, the electrons excited by the light waves excite other electrons in a cascade to generate a large number of electrons, resulting in a dramatic increase in signal intensity. To increase. According to computer simulation using the Monte Carlo method, it is shown that an increase in intensity of about 10,000 times is expected, although it depends on the type of energy and material. If the energy of the light wave that excites such photoelectrons and secondary electrons is fixed at a wavelength at which an X-ray absorption fine structure (XAFS, in particular, XANES or NEXAFS) can be obtained, chemical bond information is provided. In this way, combining a technique that improves resolution by removing spherical aberration and chromatic aberration, increases signal intensity using low energy photoelectrons and secondary electrons, and obtains chemical bond information. A new microscope with a high resolution and a high signal intensity can be obtained.

  That is, the present invention includes the following inventions 1) to 10) as industrially useful electron / secondary ion microscope apparatuses.

  1) In an electron / secondary ion microscope apparatus for imaging photoelectrons, secondary electrons, or secondary ions emitted from a sample surface to be observed in a vacuum using a short wavelength electromagnetic wave including a light wave as an excitation light source, a) An imaging optical system for imaging the photoelectron, secondary electron or secondary ion, and (b) the wavelength of the electromagnetic wave is fixed to a specific wavelength of the X-ray absorption fine structure (XAFS) having chemical information of the sample. An electron / secondary ion microscope comprising: a wavelength fixing unit that performs the above-described operation; and (c) an aberration removing mechanism that removes the influence of spherical aberration and chromatic aberration of the imaging optical system.

  2) The (c) aberration removing mechanism includes an image detection means for accumulating and accumulating images at a high speed by changing the focal position of the imaging optical system, a middle / high-frequency spatial wavelength enhancement filter, and the imaging optics. The electron / secondary ion microscope according to 1), further comprising a focal position change (modulation) means for removing the influence of spherical aberration and chromatic aberration of the system.

  3) The electron / secondary ion microscope according to 1), wherein the aberration removing mechanism (c) includes means for removing the influence of spherical aberration and chromatic aberration by correcting the electron trajectory of the electron optical system.

  4) The above-mentioned (b) wavelength fixing means obtains chemical information by obtaining the X-ray absorption fine structure (XAFS) of the sample from the difference between the peak of the absorption edge and the background. Ion microscope.

  5) The electron / secondary ion microscope according to 1), wherein XAFS obtained by the wavelength fixing means (b) is an X-ray absorption edge fine structure (XANES or NEXAFS).

  6) The above-mentioned (a) wavelength fixing means draws a chemical bond map for obtaining an image by sweeping the wavelength positions corresponding to the intensity of two or more XANES or NEXAFS due to the difference in bonding. Next ion microscope.

  7) The electron / secondary ion microscope according to 1), in which a light wave incident from a high-intensity light source or an equivalent high-intensity light source is used as the excitation light source.

  8) The electron / secondary ion microscope according to 7), wherein the high-intensity light source emitted from the excitation light source is emitted light.

  9) The electron / secondary ion microscope according to 1), wherein the secondary electrons include Auger electrons.

  10) The electron / secondary ion microscope according to 1), further comprising screen means for observing an image and energy analysis means provided between the imaging optical system and the screen means.

  As described above, the electron / secondary ion microscope apparatus according to the present invention uses a combination of spherical aberration / chromatic aberration removal and analysis by XAFS. Therefore, not only the spherical aberration and the chromatic aberration can be removed at the same time, but also the lack of intensity of the excitation light source such as the radiation light can be improved by using XAFS. Further, since XAFS, particularly XANES or NEXAFS is used, not only information on the chemical bonding state of the sample surface can be obtained, but also wavelength modulation of the emitted light used can be used.

  Therefore, the electron / secondary ion microscope apparatus according to the present invention can realize imaging with almost no aberration and further improved resolution in a state close to real time, and further improve the resolution. There is an effect that it becomes possible.

  Furthermore, since the basic structure of the photoelectron microscope, which is an example of the electron / secondary ion microscope, is the same as that of the low-energy electron microscope as described above, a composite apparatus that combines these is also being developed. However, the present invention can also be applied to such a composite apparatus.

  One embodiment of the present invention will be described below with reference to FIGS. 1 to 6 and FIGS. 8 to 15. However, the present invention is not limited to this.

  In this embodiment, an outline of the “focal position modulation spherical aberration removal method” and XAFS used in the present invention will be described, and then a photoelectron microscope as an example of an electron / secondary ion microscope apparatus according to the present invention, and An electron microscope having functions of a photoelectron microscope and a low energy electron microscope as another example will be described in detail.

(1) About “focal position modulation spherical aberration removal method” and XAFS <focal position modulation spherical aberration removal method>
First, the “focal position modulation spherical aberration removal method”, which is the principle underlying the present invention, will be described with reference to FIGS. In the “focal position modulation spherical aberration removal method”, first, the influence of main and higher order spherical aberration having a rotation invariant wavefront aberration function is removed. For this purpose, the Heusler-type focal depth expansion method is used. In the following, the principle of depth-of-focus expansion by the moving average method of defocus amount and the extraction of aberration-free information will be described from an optical standpoint.

  First, imaging of a self-luminous body (including photoelectrons) and the influence of spherical aberration will be shown. FIG. 8 shows a state in which a light wave or electron wave emitted from one point on the sample 1 and a substance wave for ions reach the rear focal plane (imaging plane) 3 through the imaging optical system drawn by the convex lens 2. Is shown from both geometrical and wavefront optics.

  As described above, light waves emitted from different points on the sample 1 do not interfere. Only light waves emitted from the same point contribute to interference. In wavefront optics, spherical waves emitted from a point sample are regarded as a collection of plane waves traveling in each direction. The imaging optical system changes the direction of these plane waves incident on the pupil (entrance pupil) and collects them at the rear focal position.

  In the aberration-free optical system shown in FIG. 9, the phases of these plane waves coincide with each other at the rear focal position 4, and a small spot is formed. On the other hand, in the optical system with spherical aberration shown in FIG. 10, the phase of the plane wave changes (the wavefront moves) in proportion to the fourth power of the angle formed by the optical axis and the plane wave traveling direction. As a result, the phase of these plane waves does not match at the rear focal position 4, resulting in a large spot.

  The above situation will be limited to a set of two plane waves with different traveling directions. Real-time imaging can be described by a collection of interference fringes caused by these different sets of plane waves.

  FIG. 11 shows a three-dimensional interference fringe 7 generated around a rear focal position (focal plane) 6 by a two-plane wave emitted from a point sample and passing through the imaging optical system 5. Note that the wavefront moves at the speed of light, but the three-dimensional interference fringes 7 do not move. When the traveling directions of the two plane waves are at the same angle with respect to the optical axis 8, the three-dimensional interference fringes 7 are parallel to the optical axis 8 as shown in FIG. 11.

  On the other hand, FIG. 12 shows a case where the traveling directions of the two plane waves are the same with respect to the optical axis 8 and have a larger angle. As described above, the interference fringe interval viewed from the focal plane 6 is almost inversely proportional to the angle formed by the traveling directions of the two plane waves.

  As shown in FIGS. 11 and 12, if there is no spherical aberration, one of the peaks of interference fringes (high intensity) is located at the origin position of the rear focal point. When the traveling directions of the two plane waves are the same angle with respect to the optical axis, the observed interference fringes do not move when the focal position is changed.

  On the other hand, as shown in FIG. 13, when the angle between the optical axis 8 and the traveling direction of the two plane waves is different, the interference fringes are observed to move when the focal position 6 is changed. Thus, even if the focal position 6 is changed only when the angles formed by the traveling directions of the two plane waves are equal, the observed interference fringes do not move.

  When there is spherical aberration, the phase of the two plane waves changes in proportion to the fourth power of the angle formed by the optical axis 8 and the plane wave traveling direction, as shown in FIG. Along with this, the three-dimensional interference fringes 7 also move in proportion to the difference in phase shift between these two plane waves. As a result, the peak of the interference fringe (strong intensity) deviates from the origin position of the rear focal point.

  However, as shown in FIG. 15, when the angles formed by the traveling directions of the two plane waves are equal, the difference between the phase shifts of the two plane waves becomes zero. Is located at the origin position of the rear focal point. At this time, even if the focal position 6 is changed, the interference fringes are observed to be stationary. All the three-dimensional interference fringes 7 parallel to the optical axis 8 are not affected by the spherical aberration. Conversely, if only the interference fringes that are observed to remain stationary even when the focal position 6 is changed, that is, only the interference fringes with an increased focal depth are extracted, an aberration imaging that is not affected by the spherical aberration is obtained. realizable. This is the principle of the aberration-free imaging method based on the expansion of the focal depth.

  Next, the depth of focus expansion method performed by Heusler will be described. First, the observed positions are continuously changed and the observed images are integrated (focus moving average method). As a result, most of the interference fringes (three-dimensional interference fringes not parallel to the optical axis) that move due to the change of the focal position are removed, and an image with a deep focal depth is obtained. According to the principle of the present method, this makes it possible to realize aberration-free imaging. However, since the interference fringes that move with the change of the focal position are removed, it is indispensable to emphasize the middle and high frequencies to compensate for their contribution. When the spherical aberration coefficient is large, the focal distance required for non-aberration imaging increases. Also, a larger mid / high frequency enhancement process is required.

  On the other hand, in terms of chromatic aberration included in the imaging optical system, this essentially has the same effect as the focal moving average. In this non-aberration imaging method, it is possible to incorporate chromatic aberration into the process of focal moving average, and the chromatic aberration can be substantially removed and ignored. If the focal movement range due to chromatic aberration is close to or exceeds the focal movement distance required for aberration-free imaging, the focal moving average is completely unnecessary.

  The features and advantages of this spherical aberration removal method can be realized by an extremely simple operation of (a) focal moving average, and real-time processing is possible. (B) There is no need to know the spherical aberration coefficient. (C) Chromatic aberration important in an electron optical system or the like can be substantially removed and ignored. (D) Light waves (electromagnetic waves), electrons, charged particle beams, and sound waves are transmitted to transmission / reflection microscopes and dark field illumination microscopes under incoherent illumination that exhibit the same imaging characteristics as those of self-luminous materials (including fluorescence). It is applicable regardless. Etc.

  Although this method uses the Heusler-type method of expanding the depth of focus, it is intended only for processing spherical and chromatic aberrations of the imaging optical system, and collects the depth direction information of the observation sample. The direction of application is completely different from the depth-of-focus processing to be shown and belongs to a different application field.

  An electron microscope that realizes high aberration-free resolution using the “focal position modulation spherical aberration elimination method” as described above has been developed (see, for example, Patent Document 1). An electron microscope to which this focal position modulation spherical aberration removing method is applied has an advantage that the spherical aberration can be removed even if the aperture diameter inside the electron microscope is large to some extent, so that the resolution can be increased. However, as described above, since the imaging mechanism is different between the conventional electron microscope and the photoelectron microscope, this method cannot be applied as it is.

<XAFS>
X-ray diffraction is performed by irradiating a sample with characteristic X-rays such as CuKα ray and MoKα ray and analyzing the peak profile of the diffracted X-ray to obtain the crystal structure. In X-ray Absorption Spectroscopy, The local structure of the substance is obtained by measuring the absorption coefficient (absorbance) of X-rays with high energy resolution. More specifically, X-ray absorption spectroscopy utilizes the fact that irradiated X-rays are absorbed by a substance and attenuated.

In the spectrum of the X-ray absorption coefficient, as shown in FIG. 2, the mass absorption coefficient μ decreases with a decrease in the X-ray wavelength λ, but there is a portion where it rapidly increases at a certain wavelength. This discontinuous part is called an absorption end. The absorption edge is referred to as a K absorption edge (one), an L absorption edge (three from L _{I to} L _III ), etc. from the short wavelength side.

  When this absorption edge is analyzed in more detail, as shown in FIG. 3, absorption rapidly rises at the absorption edge and gradually decreases toward a shorter wavelength (high energy) side. The relatively sharp absorption that appears in the vicinity of the absorption edge is called X-ray absorption near edge structure (XANES or Near Edge X-ray Absorption Fine Structure, NEXAFS), on the higher energy side than XANES or NEXAFS. The periodic absorption appearing in a wide region of about 1 keV is referred to as Extended X-ray Absorption Fine Structure (EXAFS). Both of these are collectively referred to as an X-ray absorption fine structure (XAFS).

  Since the X-ray absorption spectrum is specific to the state of the substance, the state of the sample can be determined only by comparing the spectra. In particular, since XANES or NEXAFS strongly reflects the electronic structure and symmetry of the central atom, information on the electronic state such as the valence of the atom can be obtained. Further, since EXAFS depends on the distance from the atom that absorbs X-rays to the surrounding atoms, the number of atoms, the backscattering factor, etc., information on the structure between the atoms that contribute to absorption and the surrounding scattered atoms Is obtained. Thus, XAFS has a very large signal amount.

  The present inventors can obtain an image with improved resolution in a photoelectron microscope by combining XAFS with X-ray energy and removing spherical aberration and chromatic aberration by a focal position modulation spherical aberration removal method. As a result, the present invention has been completed.

(2) An example of an electron / secondary ion microscope apparatus according to the present invention A photoelectron microscope (PEEM) apparatus will be described as an example of an electron / secondary ion microscope apparatus according to the present invention. PEEM uses synchrotron radiation as an electromagnetic wave and forms an image of photoelectrons emitted from a sample surface to be observed into a vacuum. In particular, in the present invention, the real-time focal position modulation spherical aberration removal method is applied. In addition, when analyzing a photoelectron image, imaging close to real time is enabled by using the X-ray absorption edge of the XAFS.

<Example of configuration of PEEM device>
Here, in PEEM, all methods for removing spherical aberration and chromatic aberration can be used, but a case where a real-time focal position modulation spherical aberration removing method is applied will be described as an example.

  Specifically, for example, as shown in FIG. 1, the PEEM apparatus according to the present embodiment includes an electron / secondary ion microscope apparatus according to the present embodiment, a sample holder (sample holder) 11 and an incident optical system 12. , Imaging optical system 13, screen (screen means) 14, angle modulation section (wavelength fixing means) 15, focus position modulation section (focus position changing means) 16, CCD camera (imaging means) 17, image processing section (image) Processing means) 18, a control unit 19, a monitor 20, and the like. The image processing unit 18 includes an image integrator (image detection unit) 81, a real-time Fourier processor 82, and an image analysis unit (image analysis unit / absorption edge analysis unit) 83.

  The image accumulating unit (image detecting unit) 81, the focal position modulating unit (focal position changing unit) 16, and the real time Fourier processor 82 constitute an aberration removing mechanism. In other words, the aberration removing mechanism includes an image integration unit 81, a mid / high frequency spatial wavelength enhancement filter included in the real-time Fourier processor 82, and the focal position modulation unit 16. This aberration removing mechanism is a mechanism for removing the influence of spherical aberration and chromatic aberration of the imaging optical system 13. Each means / member can be roughly divided into a PEEM portion and a control / image processing portion.

  The sample holding unit 11 holds a sample to be observed, and its specific configuration is not particularly limited, and a configuration used in a conventional PEEM can be suitably used.

  The incident optical system 12 makes electromagnetic waves such as radiated light incident on the sample holder 11, and its specific configuration is not particularly limited. In the present embodiment, as shown in FIG. 1, a multilayer film reflecting mirror 21 and an aperture 22 are provided. The multilayer film reflected light 21 reflects / spects the radiated light emitted from a radiant light source (not shown) toward the sample holder 11, and the aperture 22 limits the capture angle of the reflected radiated light.

  Specifically, before the excitation light (radiated light) is irradiated onto the sample, the incident beam is once irradiated onto the spectroscope such as the multilayer film reflecting mirror 21 and the angle of the spectroscope is set in real time. A method of changing (modulating) the wavelength of the incident beam by changing (modulating) can be mentioned. Note that the method of changing the wavelength of the excitation light is not limited to this, and the present invention also includes a method capable of changing the wavelength of the excitation light by appropriately using other conventionally known methods.

  More specific configurations of the multilayer-film reflective mirror 21 and the aperture 22 are not particularly limited, and known configurations can be suitably used. As will be described later, the angle of the multilayer-film reflective mirror 21 is controlled by an angle modulator 15 described later. That is, the angle of the multilayer film reflecting mirror 21 can be changed.

  In this embodiment, excitation light is used as a short wavelength electromagnetic wave including a light wave. The excitation light is preferably very strong light such as synchrotron radiation. Examples of the “radiation light” include, but are not limited to, radiation light obtained from the beam line of the synchrotron radiation facility SPring-8. Further, the electromagnetic wave used in the electron / secondary ion microscope apparatus according to the present invention is not limited to the excitation light such as the radiated light, but is a short wavelength electromagnetic wave including a light wave, and irradiates the sample with the electromagnetic wave. Thus, any material capable of emitting photoelectrons, secondary electrons, or secondary ions from the sample surface may be used.

  The imaging optical system 13 forms an image of photoelectrons, secondary electrons, or secondary ions emitted from the sample surface into the vacuum. In this embodiment, the imaging optical system 13 is emitted from the sample surface upon incidence of excitation light. The photoelectrons are imaged on the screen 14. A more specific configuration of the imaging optical system 13 is not particularly limited. For example, in FIG. 1, a configuration including an objective lens 31, a construct aperture 32, a projection lens 33, and the like can be given. The photoelectrons obtained from the sample surface are imaged by the objective lens 31, but the capture angle is limited by the contrast aperture 32, and the intermediate and high frequency spatial wavelength enhancement filters included in the real-time Fourier processor 82 The high spatial wavelength is emphasized, magnified and projected by the projection lens 33 and imaged on the screen 14. An intermediate lens may be provided between the contrast aperture 32 and the projection lens 33. In this case, photoelectrons may be imaged at the entrance of the projection lens 33 by the intermediate lens and projected by the projection lens 33. There is no particular limitation on the method and configuration for making the inside of the imaging optical system 13 in a vacuum state, and a known method and configuration can be suitably used.

  As will be described later, spherical aberration and chromatic aberration are removed from the objective lens 31 and the projection lens 33 by the focal position modulation unit 16.

  The screen 14 projects an image formed by the imaging optical system, and its specific configuration is not particularly limited, and a configuration used in a conventional PEEM apparatus is preferably used. it can. In the electron / secondary ion microscope apparatus according to the present invention, the basic structure of the PEEM is formed by the sample holder 12, the imaging optical system 13, and the screen 14.

  The angle modulation unit 15 is a wavelength fixing unit that fixes the wavelength of excitation light (electromagnetic wave) such as radiated light to a specific wavelength having chemical information on the absorption edge of the sample. By changing the angle of the multilayer reflector 21 included in the system 12 (that is, changing the energy of the radiated light), the wavelength of the excitation light incident on the sample is fixed to the specific wavelength. The specific configuration of the angle modulation unit 15 is not particularly limited as long as the angle of the multilayer reflector 21 can be changed by a synchronization signal output from the control unit 19 described later. Further, the specific configuration of the wavelength fixing means is not limited to the angle modulation unit 15, and for example, a known appropriate configuration can be selected according to the type of electromagnetic wave.

  Here, in the angle modulation unit 15, XANES or NEXAFS of the sample obtained from the analysis / processing result of the image processing unit 18 described later is used as information serving as a reference for changing the angle of the multilayer film reflecting mirror 21. Is preferred. By controlling the operation of the incident optical system 12 based on XANES or NEXAFS, the wavelength of the emitted light can be controlled more appropriately.

  The focal position modulator 16 changes the focal position of the imaging optical system 13 at high speed and removes the influence of spherical aberration and chromatic aberration of the imaging optical system. Specifically, the focal position modulator 16 is described later. The focal position of the imaging optical system is changed by changing (modulating) the objective lens 31 and the projection lens 33 of the photoelectron microscope in accordance with the synchronization signal output from. As an objective lens of a photoelectron microscope, there are a magnetic field type and an electric field type. In the present invention, both types can be targeted.

  When the electric field type objective lens is changed (modulated), for example, the objective lens is configured as shown in the diagram on the left side of FIG. 4A, and the electric field type objective lens 10 that can change (modulate) the electric field. This can be realized by manufacturing. When changing (modulating) the magnetic field type objective lens, for example, the objective lens is configured as shown in the right side of FIG. 4A to change (modulate) the magnetic field objective. This can be realized by manufacturing the lens 10. Note that the method for changing (modulating) the objective lens is not limited to these, and the present invention also includes a method for changing (modulating) the objective lens by appropriately using other conventionally known methods. It is.

  By changing (modulating) the objective lens of the photoelectron microscope in this manner, images with different focal positions can be acquired at high speed, and as a result, the focal position of the imaging optical system can be changed.

  As another specific method for changing the focal position (modulation) in the photoelectron microscope, a method for changing the focal position of the imaging optical system by changing (modulating) the position of the observation object (sample) in the photoelectron microscope. Can be mentioned. As a specific method for changing (modulating) the position of the sample, for example, as shown in FIG. 4B, the distance between the sample 1 and the objective lens 10 irradiated with the excitation light (here, radiated light) 31 is used. Can be changed (modulated), that is, a method of moving the position of the sample 1 in a direction in which the distance between the sample 1 and the objective lens 10 becomes longer or shorter (a double-headed arrow in the figure). The method for changing (modulating) the sample position is not limited to this, and the present invention also includes a method for changing (modulating) the sample position by appropriately using other conventionally known methods. It is.

  As described above, in the present invention, the spherical aberration / chromatic aberration is removed by adopting the real-time focal position modulation spherical aberration removing method. As a result, an aberration-free image can be obtained, and if this image is analyzed, it is possible to perform imaging with removal of artifacts due to spherical aberration.

  The CCD camera 17 captures a photoelectron image formed on the screen 14 and outputs it to the image processing unit 18 as image data. Imaging means for imaging an image formed on the screen 14 is not limited to the CCD camera 17, and a known image input device can be used.

  The image processing unit 18 analyzes the image data obtained from the CCD camera 17 and generates display information for display on the monitor 20 or generates control data to be used for control in the control unit 19. To do. As described above, the image processing unit 18 in the present embodiment includes the image integrator 81, the real-time Fourier processor 82, and the image analysis unit 83.

  The image accumulator 81 is image detecting means for accumulating and accumulating images on the imaging plane, and accumulates and accumulates image data captured by the CCD camera 17 and outputs it to the real-time Fourier processor 82. The real-time Fourier processor 82 performs Fourier transform processing and medium / high spatial wavelength enhancement processing on the image data obtained from the image integrator 81. By this middle / high spatial wavelength enhancement processing, the above-described middle / high spatial wavelength enhancement filter is added in terms of software. The image data is further subjected to image analysis by the image analysis unit 83 and output to the monitor 20.

  The image data picked up by the CCD camera 17 and input to the image accumulator 81 is obtained by removing the spherical aberration and chromatic aberration of the imaging optical system 13 by the focal position modulation unit 16. By analyzing XAFS included in the image information after removing the aberration, it is an absorption edge analyzing means for obtaining information on the chemical bonding state of the sample surface. As a result, not only imaging close to real time is possible, but also the amount of signal obtained by XAFS can be increased by about 4 digits, so that high-speed image capture is possible.

  When synchrotron radiation is used as the excitation light source, the signal intensity of the photoelectron obtained from the inner shell electron level is weak because the excitation cross section of the electromagnetic wave used for excitation is small. Therefore, when excitation light such as synchrotron radiation is used, the electron / secondary ion microscope apparatus uses extremely strong electromagnetic waves to improve the resolution of the photoelectron microscope by removing spherical aberration and chromatic aberration in real time. There is a need to. However, even with synchrotron radiation, there are limits to the intensity that can be obtained with current technology. Therefore, in the present invention, by using XAFS, it is possible to obtain a high-resolution image including chemical bond information, so that it is possible to remove spherical aberration and chromatic aberration and obtain a high-speed and high-resolution photoelectron microscope. It becomes possible.

  The specific configuration of the image processing unit 18 is not particularly limited, and various processors that enable the above-described image processing can be used. The processor may be an independent computer such as a personal computer, or may be integrated into at least one of the CCD camera 17 and the monitor 20 as a chip.

  The monitor 20 is an image display means for displaying the image data obtained from the image processing unit 18 so as to be visible. The configuration of the monitor 20 is not particularly limited, and a liquid crystal display device, a plasma display display device, an organic electroluminescence device, or the like. A known display device such as a display device or a CRT display device can be used. In addition, image forming means such as various printers may be provided as needed. The image data obtained in this way can be not only a soft copy on the display screen but also a hard copy printed on various papers.

  The angle modulation unit 15, the focus position modulation unit 16, the CCD camera 17, the image processing unit 18, the control unit 19, the monitor 20, and the like constitute a control / image processing unit. Needless to say, the PEEM apparatus according to the present embodiment may include means and members other than the above-described means and members. For example, storage means such as various memories and flexible disk drives may be provided, an input device such as a keyboard may be provided, or communication means that can be connected to a network may be provided.

<Example of operation of PEEM device>
In the PEEM apparatus having the above configuration, the real-time focal position modulation spherical aberration removing method and XAFS can improve the insufficient intensity of the emitted light, and the spherical aberration and chromatic aberration can be well removed, and imaging close to real time becomes possible.

  An example of operation control of the PEEM apparatus in the present embodiment will be described. Specifically, for example, nine-step control as shown in FIG. 5 can be mentioned. First, in step (hereinafter, step is abbreviated as S as appropriate) 1, the wavelength of the emitted light incident on the control unit 19 based on information stored in a memory (not shown) or information input by an input means (not shown). Is determined to be modulated. If it is not necessary to modulate the wavelength (NO in the figure), the process proceeds to S3. If it is necessary to modulate the wavelength (YES in the figure), the process proceeds to S2, and the control unit 19 outputs a synchronization signal to the angle modulation unit 15, and changes the angle of the multilayer mirror 21 to change the wavelength of the emitted light. Is fixed to a specific wavelength having chemical information of the absorption edge of the sample to be observed (wavelength fixing step).

  Next, in S3, it is determined whether or not the focal position of the objective lens 31 and the like in the imaging optical system 13 is changed. Usually, since aberrations such as spherical aberration need to be removed, in this case (YES in the figure), the process proceeds to S4, on the basis of information stored in a memory (not shown) or information input by an input means (not shown). The control unit 19 outputs a synchronization signal to the focal position modulation unit 16 to change the focal position of the objective lens 31 and the like (focal position modulation step). On the other hand, if aberration removal is not performed at this stage (NO in the figure), the process proceeds to S5.

  Next, in S <b> 5, the control unit 19 causes the CCD camera 17 to capture the photoelectron image formed on the surface of the screen 14 and causes the image integration unit 81 of the image processing unit 18 to accumulate and accumulate images. Thereafter, the process proceeds to S6, where the real-time Fourier processor 82 performs the Fourier transform processing and the middle / high spatial wavelength enhancement processing, and then the image analysis unit 83 performs image analysis (image analysis step). Based on the image analysis result obtained at this time, the control unit 19 re-modulates the wavelength in S7, that is, changes the specific wavelength for obtaining the XAFS again to obtain a more preferable (more data amount) wavelength. It is determined whether or not. If it is determined that it is not necessary (NO in the figure), the process proceeds to S8, but if it is determined that remodulation is necessary (YES in the figure), the process returns to S1.

  At this time, in S6, since the X-ray absorption edge fine structure (XANES or NEXAFS) of the sample is obtained from the difference between the peak of the absorption edge and the background from the image analysis unit 83, the control unit 19 in S1 Based on this, the operation of the angle modulator 15 is controlled, and the wavelength of the emitted light is changed and fixed to the specific wavelength. The shape of the fine structure at the X-ray absorption edge of XAFS changes due to chemical bonding as described above. Not only can this be used to obtain information on the chemical bonding state, but it can also be used for wavelength modulation of the emitted light used, so that the resolution of the electron / secondary ion microscope apparatus according to the present invention can be improved. Not only the improvement but also the control accuracy can be improved.

  Next, in S8, it is determined whether or not readjustment of the focal position change is necessary. If readjustment is necessary (YES in the figure), the process returns to S4. If readjustment is not necessary (NO in the figure), the process proceeds to S9. In the determination in S8 and the readjustment of the focal position change in S4, the analysis result obtained from the image analysis unit 83 may be used as in S7. Thereby, since spherical aberration and chromatic aberration can be removed based on the obtained image data, not only the resolution of the electron / secondary ion microscope apparatus according to the present invention but also the control accuracy can be improved.

  Finally, in S9, an almost aberration-free image including information on the chemical bonding state of the sample surface obtained by the series of controls is displayed on the monitor 20. An observer can visually obtain information on the sample surface from the information on the monitor 20.

(3) Other Example of Electron / Secondary Ion Microscope Apparatus According to the Present Invention In the above (2), the electron / secondary ion microscope apparatus according to the present invention has been described by taking only the PEEM apparatus as an example. However, the present invention is not limited to this, and for example, as shown in FIG. 6, an electron microscope having a configuration combining a PEEM and a low energy electron microscope (LEEM) may be used. As described above, since the basic configuration of PEEM and LEEM is the same, a composite apparatus that combines them is also being developed. The present invention can also be applied to such a composite apparatus.

<Example of configuration of PEEM / LEEM combined type device>
An example of the PEEM / LEEM combined type apparatus will be described. As shown in FIG. 6, the sample holder 11, the electron gun 41, the second incident optical system 42, the deflecting magnet (deflecting means) 43, the objective optical system 44, the connection optical system, and the like. Examples include a configuration including the image optical systems 13a and 13b, an energy analyzer (energy analyzing means) 45, a screen 46, various apertures 51, 52, and 53, a slit 54, and the like.

  Since the sample holder 11 is the same as the PEEM apparatus described in (2) above, its description is omitted. In addition, the configuration for entering the radiant light (hν in the figure) incident on the sample holding unit 11 only needs to include the incident optical system 12 and the angle modulation unit 15 similar to the PEEM apparatus described in the above (2). Detailed description thereof will be omitted.

  The electron gun 41 emits a low-energy electron beam, and its configuration is not particularly limited, and those used in known LEEM devices can be suitably used. Further, the second incident optical system 42 is for making the electron beam emitted from the electron gun 41 enter the deflecting magnet 43, and similarly to the electron gun 41, the one used in the known LEEM apparatus is preferably used. Can do.

  The deflection magnet 43 deflects the electron beam emitted through the second incident optical system 42 toward the sample holding unit 11 and deflects the electron beam obtained from the sample with respect to the imaging optical system. . In the configuration of the present embodiment, as shown in FIG. 6, an electron beam is emitted obliquely from the lower left electron gun 41 in the figure toward the upper right direction. Therefore, the second incident optical system 42 is also inclined and arranged in the upper right direction in the drawing. On the other hand, the surface of the sample holder 11 is not arranged so as to face the electron gun 41 and the second incident optical system 42, and is displaced within an acute angle range from the extended line of the second incident optical system 42. It is arranged at the position. Therefore, the electron beam is deflected by the deflecting magnet 43 so that the electron beam emitted from the electron gun 41 and the second incident optical system 42 is incident on the surface of the sample holder 11 perpendicularly. The specific configuration of the deflection magnet 43 is not particularly limited, and a known one can be suitably used.

  The objective optical system 44 causes the electron beam deflected by the deflecting magnet 43 to be incident on the sample on the sample holding unit 11, and when used as a LEEM, the reflected electron beam reflected by the sample is used as a PEEM. In this case, a photoelectron beam obtained from the sample is incident on the deflection magnet 43. The specific configuration is not particularly limited as long as the configuration includes an objective lens and the like.

  The imaging optical systems 13a and 13b are for imaging an electron beam obtained from a sample on the screen 46, and may basically have the same configuration as the imaging optical system 13, but the present embodiment Then, since the energy analyzer 45 exists, it can be divided into the imaging optical system 13a in the preceding stage of the energy analyzer 45 and the imaging optical system 13b in the subsequent stage. The imaging optical system 13a only needs to be configured so that an electron beam can be incident on the energy analyzer 45. Similarly, the imaging optical system 13b transmits the electron beam obtained via the energy analysis gas 45 onto the screen 46. Any configuration capable of forming an image may be used, and any configuration is not particularly limited.

  The energy analyzer 45 is provided between the imaging optical system and the screen unit, analyzes the energy of the electron beam obtained from the sample, and can be used for XAFS analysis and the like. Therefore, the energy analyzer 45 only needs to be able to output the obtained analysis data to the image processing unit 18 described above. The specific configuration of the energy analyzer 45 is not particularly limited, and a known configuration can be suitably used.

  The apertures 51 to 53 limit the angle at which electromagnetic waves such as incident electron beams are captured. Specifically, the aperture 51 is an illumination aperture for limiting the incident beam, the aperture 52 is a limited field aperture for limiting the field of view during observation, and the aperture 53 is a contrast aperture for improving the contrast. It is. The slit 54 is for selecting energy. The configuration of any of the apertures 51 to 53 and the slit 54 is not particularly limited, and a known configuration can be suitably used.

<Example of operation of PEEM / LEEM combined device>
Also in the PEEM / LEEM combined apparatus, since the wavelength fixing step, the focal position modulation step, and the image analysis step are performed as in the operation of the PEEM apparatus of (2) (see FIG. 5), control / image processing is performed. Although the specific description regarding is omitted, the case where each is used as LEEM and PEEM will be described.

  When the PEEM / LEEM combined apparatus is used as a LEEM, first, an electron beam emitted from the electron gun 41 is passed through a second incident optical system 42, a deflection magnet 43, and an objective optical system 44. 11 is incident on the sample. At this time, the incident electrons are rapidly decelerated immediately before the sample. The incident electrons interact with the sample, are elastically scattered, are emitted from the sample as reflected electron beams, and are rapidly accelerated by an accelerating electric field. The obtained reflected electron beam (photoelectron beam) is incident on the screen 46 through the objective optical system 44, the deflection magnet 43, the imaging optical system 13a, the energy analyzer 45, and the imaging optical system 13b to form an image. Similar to the PEEM apparatus of (2), this image is picked up by an image pickup means such as a CCD camera (not shown), analyzed and displayed on a monitor, and used for controlling aberration removal as needed.

  On the other hand, when used as a PEEM, first, excitation light such as radiated light is incident on a sample on the sample holding unit 11 via an incident optical system (not shown). As a result, photoelectrons are emitted from the sample surface, and the resulting photoelectron beam is transferred to the screen 46 via the objective optical system 44, the deflection magnet 43, the imaging optical system 13a, the energy analyzer 45, and the imaging optical system 13b. Make an incident image. Similar to the PEEM apparatus of (2), this image is picked up by an image pickup means such as a CCD camera (not shown), displayed on a monitor after image analysis, and used for aberration removal control as necessary.

  Thus, the present invention can be applied to various types of electron / secondary ion microscope apparatuses. Therefore, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims, and the embodiments obtained by appropriately combining the respective technical means disclosed are also applicable. It is included in the technical scope of the present invention.

  As described above, according to the electron / secondary ion microscope apparatus of the present invention, not only the spherical aberration and the chromatic aberration can be simultaneously removed, but also the excitation light source such as the emitted light can be obtained by using XAFS. It is possible to realize imaging in which the intensity shortage is improved and the resolution is further improved with almost no aberration, in a state close to real time. For this reason, the present invention is not only applicable to research, development and evaluation in a very wide industrial field such as engineering (particularly materials, semiconductors, etc.), medicine, biology, astronomy, etc., but also various technologies including nanotechnology. Can contribute to new fields.

It is a schematic block diagram which shows typically the structural example of the photoelectron microscope (PEEM) apparatus which is an example of the electron and secondary ion microscope apparatus concerning this invention. It is a graph which shows an example of the X-ray absorption coefficient spectrum for demonstrating XAFS utilized by this invention. It is a graph which shows the structure of the absorption edge of the graph shown in FIG. 2 in detail, and is a graph which shows XAFS which consists of XANES and EXAFS concretely. It is a figure which shows typically the specific method of the focus position change method in the electron secondary ion microscope apparatus concerning this invention, (a) is a figure which shows the method to change the electric field or magnetic field of an objective lens typically. (B) is a figure which shows typically the method of changing a sample position. It is a flowchart which shows an example of operation control of the PEEM apparatus shown in FIG. It is a figure which shows typically the structural example of the composite-type apparatus which combines PEEM and the low energy electron microscope (LEEM) which is another example of the electron and secondary ion microscope apparatus concerning this invention. It is a figure which shows the relationship between the electron microscope and analysis method which have been developed so far for surface nano-characterization, and the photoelectron microscope which concerns on this invention. It is a figure which shows the geometric optical interpretation and wave optical interpretation regarding the image formation of a self-light-emitting body (a photoelectron is included). It is a figure which shows the wave front and intensity distribution which are synthesize | combined by the back side focal plane through a non-aberration imaging system from a point light emitter. It is a figure which shows the wave front and intensity distribution with which a back focal plane is synthesize | combined through a non-aberration imaging system with spherical aberration from a point light emitter. It is the figure which showed the three-dimensional interference fringe which the 2 plane wave which emitted from the point-like sample and passed the non-aberration imaging optical system makes around a back focal position. It is the figure which showed the three-dimensional interference fringe in case the advancing direction of two plane waves is the same with respect to an optical axis, and becomes a larger angle than the case of FIG. FIG. 3 is a diagram showing a three-dimensional interference fringe generated around a rear focal position by a two-plane wave emitted from a point-like sample and passed through a non-aberration imaging optical system when the angle between the optical axis and the two-plane wave traveling direction is different. is there. A three-dimensional interference fringe generated around a rear focal point by a two-plane wave that is emitted from a pointed sample and passed through an imaging optical system having spherical aberration is shown when the angle between the optical axis and the traveling direction of the two-plane wave is different. FIG. A three-dimensional interference fringe generated around a rear focal point by a two-plane wave emitted from a pointed sample and passed through an imaging optical system having spherical aberration is shown for the case where the angle between the optical axis and the two-plane wave traveling direction is equal. FIG.

Explanation of symbols

11 Sample holder (sample holder)
12 incident optical system 13 imaging optical system 13a / 13b imaging optical system 14 screen (screen means)
15 Angle modulator (wavelength fixing means)
16 Focus position modulator (focal position changing means)
17 CCD camera (imaging means)
18 Image processing unit (image processing means)
19 Control unit (control means)
20 Monitor (image display means)
21 Multilayer reflector (incident optical system)
41 Electron gun 42 Second incident optical system 43 Deflection magnet (deflection means)
44 Objective optical system 45 Energy analyzer (energy analysis means)
46 screen (screen means)
81 Image integrator (image detection means)
82 Real-time Fourier processor 83 Image analysis unit (image analysis means / absorption edge analysis means)

Claims (10)

In an electron / secondary ion microscope apparatus that forms an image of photoelectrons, secondary electrons, or secondary ions emitted from a sample surface to be observed into a vacuum using an electromagnetic wave having a short wavelength including light waves as an excitation light source,
(a) an imaging optical system for imaging the photoelectron, secondary electron or secondary ion;
(b) wavelength fixing means for fixing the wavelength of the electromagnetic wave to a specific wavelength of an X-ray absorption fine structure (XAFS) having chemical information of the sample;
(c) An electron / secondary ion microscope comprising an aberration removing mechanism for removing the influence of spherical aberration and chromatic aberration of the imaging optical system.   The above (c) aberration removing mechanism changes the focal position of the imaging optical system at high speed, integrates and accumulates images, medium / high frequency spatial wavelength enhancement filter, and the imaging optical system. 2. The electron / secondary ion microscope according to claim 1, further comprising focal position changing means for removing the influence of spherical aberration and chromatic aberration.   2. The electron-secondary electron beam according to claim 1, wherein the aberration removing mechanism includes means for removing the influence of spherical aberration and chromatic aberration by correcting the electron trajectory of the electron optical system. Ion microscope.   The said (b) wavelength fixing means obtains the X-ray absorption fine structure (XAFS) of a sample from the difference between the peak of the absorption edge and the background, and obtains chemical information according to claim 1, Electron / secondary ion microscope.   2. The electron / secondary ion microscope according to claim 1, wherein the XAFS obtained by the wavelength fixing means (b) has an X-ray absorption edge fine structure (XANES or NEXAFS).   The said (a) wavelength fixing means draws the chemical bond map which sweeps the wavelength position corresponding to the intensity | strength of two or more places of XANES or NEXAFS by the difference in a coupling | bonding, and obtains an image. Electron and secondary ion microscope.   2. The electron / secondary ion microscope according to claim 1, wherein a light wave incident from a high-intensity light source or an equivalent high-intensity light source is used as the excitation light source.   8. The electron / secondary ion microscope according to claim 7, wherein the high-intensity light source emitted from the excitation light source is radiation light.   The electron / secondary ion microscope according to claim 1, wherein the secondary electrons include Auger electrons.   2. The electron / secondary ion microscope according to claim 1, further comprising screen means for observing an image, and energy analysis means provided between the imaging optical system and the screen means.

Images