JP2004265879A - Element mapping device, scanning transmission electron microscope, and element mapping method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an element mapping device whereby an element mapping image can be easily obtained. <P>SOLUTION: An electron beam transmitting through an object 5 to be analyzed in this scanning transmission electron microscope enters the element mapping device. The transmitted electron beam is subjected to energy spectral analysis by a spectroscope 11 to obtain an electron energy loss spectrum. Window information used for the accelerating voltage data of each element and a two window method is prepared in advance in a data base 24, and even if the element to be analyzed is changed, a two dimensional element distribution image is immediately confirmed. Since all of the electron beam entering the spectroscope pass through an object point 10, an aberration distortion can be made small, and energy stability becomes excellent. Therefore, the drift of the energy loss spectrum lessens, and a precise element distribution can be obtained. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to an element mapping device, a scanning transmission electron microscope, and an element mapping method.

  Due to the miniaturization and miniaturization of semiconductor devices and magnetic head elements, the elements have a structure in which several NM (nanometer) thin films are stacked in a submicron region. Since the structure, element distribution, and crystal structure of such a minute region greatly affect the characteristics of the semiconductor element and the magnetic head element, it is important to analyze the minute region.

As a method for observing a minute area, a scanning electron microscope (Scanning Electron Microscope:
SEM), transmission electron microscope (TEM), and scanning transmission electron microscope (STEM). TEMs and STEMs have nanometer-level spatial resolution. The TEM is a device that irradiates a sample with an electron beam almost in parallel and enlarges the transmitted electron beam with a lens or the like. On the other hand, STEM is a device that converges an electron beam on a minute region, measures the intensity of the transmitted electron beam while scanning the electron beam two-dimensionally on a sample, and acquires a two-dimensional image.

  The intensity of transmitted electrons detected by the TEM and the STEM has a correlation with the average atomic number of the portion where the electrons have transmitted. For this reason, thin films of chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), and copper (Cu) having similar atomic numbers, and silicon oxide films and silicon having similar average atomic numbers A nitride film or the like cannot be identified.

  In the case of a metal film, it is possible to identify Cr, Mn, Fe, Co, Ni, and Cu by acquiring a two-dimensional image using X-ray fluorescence analysis. A long measurement time is required to obtain a two-dimensional image. Since X-ray fluorescence analysis is not suitable for light element analysis, it is difficult to distinguish between a silicon oxide film and a silicon nitride film.

As an analysis method for solving these problems, there is an electron energy loss spectroscopy (EELS) in which transmitted electrons are subjected to energy analysis by an electron spectroscope. When electrons pass through the sample, an energy loss specific to the element (electronic structure) constituting the sample is generated. Therefore, a two-dimensional image is formed by the electrons having the energy loss specific to the element, and is identified in the TEM / STEM image. It is possible to identify the silicon oxide film or nitride film that could not be obtained. These are a STEM and a parallel detection type electron energy loss spectrometer (Electron
It is widely used by a method combining Energy Loss Spectrometer (EELS).

  The EELS has a structure in which a fan-shaped magnetic sector is used as an electron spectrometer, a quadrupole electromagnetic lens and a hexapole electromagnetic lens are arranged before and after the sector, and a parallel detector is provided at the most downstream. The quadrupole electromagnetic lens is used for adjusting the focus of the EELS spectrum and expanding the EELS spectrum. A hexapole electromagnetic lens is used to reduce aberrations in the EELS spectrum projected on the detector. The EELS spectrum enlarged by the quadrupole electromagnetic lens is projected on a parallel detector, and a wide range of electron energy loss spectrum is measured.

As prior art relating to the structure of EELS, for example, US Pat. No. 4,743,756 (Patent Document 1), JP-A-7-21966 (Patent Document 2), and JP-A-7-21967 (Patent Document 3) ), And JP-A-7-29544 (Patent Document 4). JP-A-57-80649 (Patent Document 5) describes an electron beam energy analyzer.

U.S. Pat. No. 4,743,756 JP-A-7-21966 JP-A-7-21967 JP-A-7-29544 JP-A-57-80649

  In the conventional analyzer that combines EELS and STEM, the user (1) designates a measurement place → (2) designates an element → (3) measures the energy intensity distribution of an electron beam with an electron beam detector → (4) Correct the background correction and gain of the detection unit → (5) Specify the background area → (6) Specify the background fitting function such as the power low model (I = AE-r) → (7) Integrate the signal intensity Specifying the area → (8) Displaying the signal intensity of the specified element at the measurement location on the image display device → It is necessary to repeat the operation of (1) at all the measurement points, and it is enormous to obtain a two-dimensional image. It takes a long time, and it is difficult to obtain an element distribution image in real time. Also, a method is conceivable in which after measuring the EELS spectrum at all the measurement points, the user specifies (2) to (7) and obtains a two-dimensional image.

  In the case of this method, the amount of measured data becomes enormous, and an element distribution image cannot be obtained in real time.

As described above, when an element distribution image cannot be obtained in real time, there is the following problem.
(A) For example, when analyzing an interface between a silicon oxide film and a nitride film, a TEM /
Since the visual field is confirmed with the STEM image, the analysis region (the interface between the oxide film and the nitride film) cannot be identified. Therefore, until the EELS spectrum is measured and the element distribution image is obtained by the analysis, it cannot be determined whether or not the analysis region includes the region to be measured.
(B) For example, in order to obtain a two-dimensional image of the analysis area, the measurement of the EELS spectrum and the operations (1) to (8) described above at each measurement point are required, and much time is required for measurement and analysis. It is not suitable for work such as inspection for measuring a large number of samples.

  To solve the above problems, it is essential to obtain an element distribution image in real time.

  Further, in a conventional analyzer that combines EELS and STEM, the magnification of the spectrum is made variable using a quadrupole electromagnetic lens so that a wide range of EELS spectra can be measured from a detailed EELS spectrum.

When an element distribution image is acquired by an analyzer that combines EELS and STEM, the stability of the power supply of the electromagnetic lens and the electron spectrometer is about 5 × 10 ⁻⁶ . Here, since the acceleration voltage of the STEM is 100 kV to 200 kV, the stability of the EELS spectrum is 0.5 to 1 eV. When an element distribution image is obtained by EELS, the measurement is performed at 0.2 to 0.4 eV / channel, so that the EELS spectrum drifts by several channels during the measurement. Therefore, there is a problem that it is difficult to process an EELS spectrum in real time with a conventional analyzer that combines EELS and STEM due to drift of the EELS spectrum.

  Further, the conventional EELS has a heavy and complicated structure because a large number of electromagnets are used in a plurality of quadrupole electromagnetic lenses, hexapole electromagnetic lenses, electron spectrometers, and the like.

  In addition to the EELS main body, devices such as a power source for an electromagnet, an AC noise elimination device, and a cooling device are also required, and the configuration of the measures is complicated, resulting in an expensive device.

  Further, the conventional cold cathode field emission type STEM has a technical problem on the device called chip noise in which the brightness of the electron beam source increases during the measurement. Since the secondary electron intensity, the Z contrast intensity, the fluorescent X-ray intensity, and the EELS intensity increase during the measurement due to the chip noise, whether the increase in the intensity of the measurement area is due to the influence of the chip noise or the signal intensity increases. There is a problem that it is not possible to distinguish it because it has been done.

  As described above, it is difficult to obtain an element distribution image in real time with an analyzer that combines EELS and STEM.

  An object of the present invention is to provide an apparatus and a method capable of acquiring an element distribution image in real time with an analyzer that combines EELS and STEM.

  Another object of the present invention is to improve the operability of an analyzer relating to EELS and / or STEM.

  Another object of the present invention is to provide a device having high energy stability of the EELS spectrum.

  Another object of the present invention is to combine this with a scanning transmission electron microscope to measure an EELS spectrum, and at the same time, to obtain an element distribution image and an energy filter for an element mapping apparatus capable of obtaining an electron microscope image with less influence of chip noise. Another object of the present invention is to provide a lightweight transmission electron microscope equipped with the same.

  In addition, although a conventional element mapping apparatus can obtain a distribution image of a single element, it is difficult to obtain a distribution of a plurality of elements and observe a positional relationship of each element with a resolution of nanometer or less. Was.

  It is another object of the present invention to provide an element mapping apparatus that can easily obtain a distribution image of a plurality of elements.

  The features of the present invention include an electron beam source that generates an electron beam, a scanning unit that scans the electron beam, an objective lens that converges the electron beam on the sample, an electron spectroscope that performs energy spectroscopy of the electron beam, and an electron spectroscope. A scanning transmission electron microscope provided with an electron beam detection unit for detecting a part or all of the electron beam separated by the method, having at least an arithmetic unit for calculating using the electron beam intensity detected by the electron beam detection unit The calculation result of the arithmetic unit is displayed on the image display device at the same time or in parallel with scanning the electron beam using the scanning unit.

  Further, the feature of the present invention is that the user (operator) (1) designates a measurement place → (2) designates an element → (3) measures the energy intensity distribution of an electron beam with an electron beam detection section → (4) ) Correct the background correction and gain of the detection section → (5) Specify the background area → (6) Specify the background fitting function such as power-low model (I = AE-r) → (7) Signal strength Designation of integration area → (8) Display of signal intensity of specified element at measurement location on image display device → Operation of repeating (1) for each measurement location and measurement element to obtain element distribution image Is that the user (operator) performs (1) designation of a measurement region → (2) designation of an element, thereby executing other processing on the device side. Thereby, an element distribution image of the specified element can be obtained in real time. Further, this makes it possible to improve the operability and shorten the measurement time.

  Another feature of the present invention is that an electron beam source that generates an electron beam, a scanning unit that scans the electron beam, an objective lens that converges the electron beam on the sample, an electron spectroscopic unit that performs energy spectroscopy of the electron beam, In a scanning transmission electron microscope, provided with an electron beam detection unit that detects a part or all of the electron beam split by the spectroscopy unit, an arithmetic unit that calculates using at least the electron beam intensity detected by the electron beam detection unit And an image display device for displaying the calculation result of the arithmetic unit. A lens formed by at least one permanent magnet is provided between the electron beam energy loss spectrum (EELS spectrum) formed by the electron beam spectroscopy unit and the detection unit. It is characterized by having. Also, a feature of the present invention is that the electron spectroscopy unit is formed of a permanent magnet.

The magnetic field stability of a magnet lens using a permanent magnet is about 1 × 10 ^−8, which is more than two orders of magnitude higher than the magnetic field stability (5 × 10 ⁻⁶ ) of a lens using an electromagnet. By using a permanent magnet as the electron spectroscopy unit and the lens, the drift of the EELS spectrum can be reduced to 0.1 channel or less under the element distribution image measurement conditions.

  Thus, the scanning transmission electron microscope has a database of core loss energies of elements, the electron beam detection unit is configured with two or more channels, the core loss energies of specified elements are obtained from the database, and then the electron spectroscopy unit and the electron beam The detection unit automatically adjusts the electron optical system so that the electron beam with core loss energy is detected, and the scanning unit scans the electron beam, and at the same time, the electron beam intensity immediately before and after the core loss energy of the specified element is measured by the electron beam. Measurement is performed using at least one channel in the detection unit, background correction and gain correction of the electron beam detection unit are performed using an arithmetic unit, and the electron beam intensity immediately after core loss energy is divided by the electron beam intensity immediately before core loss energy. Then, the obtained calculation result can be displayed on the image display device in real time.

  Also, a feature of the present invention is that the scanning transmission electron microscope has a database of element core loss energies, the electron beam detection unit is configured with three or more channels, and the core loss energy of the specified element is obtained from the database. The spectroscope and electron beam detector automatically adjust the electron optical system so that the core loss energy of the electron beam is detected, and the scanning unit scans the electron beam, and at the same time, the electron beam intensity immediately before the core loss energy of the specified element Is measured using at least two channels of the electron beam detection unit, and the electron beam intensity immediately after core loss energy is measured using at least one channel of the electron beam detection unit. The arithmetic unit performs background correction and gain correction of the electron beam detection unit, and calculates the electron beam intensity immediately after the core loss energy from the electron beam intensity distribution immediately before the core loss energy based on a power-low model (I = AE-r) or the like. The background is calculated, the calculation of the electron beam intensity immediately after the core loss energy is automatically performed, and the obtained calculation result can be used as a core loss element mapping in an image display device in real time.

  Further, the scanning transmission electron microscope has a database of plasmon loss energies characteristic of each element. After obtaining the plasmon loss energies of the specified elements from the database, the electron spectroscopy section and the electron beam detection section perform the plasmon loss energy analysis. The electron optical system is automatically adjusted so that the electron beam is detected, and the electron beam is scanned by the scanning unit, and the electron beam intensity of the plasmon loss energy of the specified element is measured by the electron beam detection unit. The background correction and the gain correction of the electron beam detection unit are performed by using this, and the obtained calculation result can be used in an image display device in real time.

  Further, the electron beam detecting section is composed of two or more channels, and the electron beam intensity of the plasmon loss energy of two or more elements is measured in each channel of the electron beam detecting section, and the calculating section is used to calculate the electron beam detecting section. By performing background correction and gain correction on each channel of the electron beam detection unit, and displaying the calculation results of each channel of the electron beam detection unit in real time on an image display device in the shade of a specified color to emphasize the contrast related to a specific element. It is also possible to display a contrast tuning image.

  In addition, the electron beam detection unit is composed of two or more channels, and the electron spectroscopy unit and the electron beam detection unit automatically operate the electron optical system so that a zero-loss electron beam and an electron beam with plasmon loss energy are detected (for example, the device side). , The processing is performed based on a processing program.), The electron beam is scanned by the scanning unit, the intensity of the zero-loss electron beam is measured using at least one channel of the electron beam detecting unit, and the plasmon loss energy is measured. Is measured in at least one channel different from at least one channel of the electron beam detection unit, and the background correction and the gain correction of the electron beam detection unit are performed using an arithmetic unit, and the plasmon loss energy is calculated as zero-loss electron beam intensity. The thickness of the sample can be mapped by converting the calculation result obtained by dividing the electron beam intensity into an image display device in real time. To become.

(Background correction)
Here, the background and gain correction unique to the electron beam detection unit will be described next. The electron beam detector has a background due to thermal vibration of electrons of the detector itself even when the electron beam does not enter the detector. In addition, a detector including a plurality of channels has different sensitivity (gain) depending on each channel. Correcting these two is the background and gain correction unique to the electron beam detector. The method is as follows. First, in the background correction, in a state where the electron beam does not enter the detector, the intensity measured by the electron beam detector is stored in the recording device of the arithmetic device as a background. This is a correction in which the difference between the electron beam intensity obtained during the element distribution image measurement and the previously stored background intensity is used as the electron beam intensity.

(Gain correction)
In the gain correction, alternating current is superimposed on the drift tube while measuring zero loss so that uniform electron beam intensity enters the entire detector. The electron beam intensity is measured with an electron beam detector. The detected total electron beam intensity is divided by the number of channels to obtain an average electron dose per channel. A coefficient obtained by dividing the average electron beam intensity by the electron beam intensity measured in each channel is stored as a gain correction value for each channel in a recording device of the arithmetic device. In this correction, the electron beam intensity obtained in each channel at the time of element distribution image measurement is multiplied by the previously stored gain correction value of each channel, and the obtained intensity is used as the electron beam intensity. Further, the scanning transmission electron microscope is provided with a secondary electron detecting unit, a Z contrast detecting unit, or a fluorescent X-ray detecting unit. The intensity, the Z-contrast electron beam intensity, or the fluorescent X-ray intensity is measured at the same time, and the background correction and the gain correction of the electron beam detection unit are performed using an arithmetic unit, and the secondary electron intensity or the Z-contrast electron beam intensity Or by dividing the fluorescent X-ray intensity by the zero-loss electron beam intensity, a secondary electron image, a Z-contrast image, or a fluorescent X-ray image from which chip noise has been removed can be made into an image display device in real time. Become.

(Z contrast intensity)
Here, the Z contrast intensity will be described. When an electron beam accelerated to several hundred keV converges to the thickness of an atomic level and enters the sample, the electron beam is scattered in various directions by atoms constituting the sample. Since the angle and the intensity are determined by the atomic scattering ability depending on the atomic number, if a foreign atom is present in the base material atoms, the scattering intensity from that atomic sequence will be different from those from other atomic sequences. Therefore, if the scattered electron beam intensity at each position is measured in synchronization with the scanning of the electron beam on the sample, a two-dimensional image having a contrast depending on the atomic species can be obtained. The contrast is approximately proportional to the 2/3 power of the atomic number. In an electron microscope, an image is obtained from the electron beam intensity scattered at a wide angle of 50 mrad or more. This contrast intensity is expressed as Z contrast intensity. Further details are described, for example, in the literature: SJ Pennycook and DE Jesson: Ultaramaicroscopy 37 (1991) 14-38.

  The focus of the EELS spectrum is between the electron beam spectroscopy unit and the electron beam detection unit, and the EELS spectrum is focused at the same place in both the X direction and the Y direction. By expanding the EELS spectrum equally in the X direction and the Y direction using an expanding magnetic field lens and projecting the EELS spectrum to the electron beam detection unit, it is possible to suppress aberration distortion of the EELS spectrum that is enlarged and projected to a low level.

  The magnification magnetic field lens is composed of a permanent magnet lens for magnification and an electromagnetic lens for adjusting the focus to the imaged region of the EELS spectrum, so that the magnification of the EELS spectrum is fixed.

  Conventionally, an electromagnetic lens has been used because it is necessary to change the energy dispersion (magnification). According to the present invention, since the energy dispersion (magnification) can be fixed, a permanent magnet lens having high magnetic field stability can be used. As a result, in the present invention, the magnification of the EELS spectrum is fixed, so that a process of dividing and measuring the EELS spectrum in a wider range is required as compared with an apparatus using a quadrupole electromagnetic lens. However, the use of the permanent magnet has an effect that adjustment of the lens optical system is not required. In addition, since the drift of the EELS spectrum is reduced due to the magnetic field stability of the permanent magnet, automatic measurement and calculation of the EELS spectrum can be performed. Further, the permanent magnet lens is cheaper and lighter than an electromagnetic lens, and does not require wiring, a power supply, and a cooling mechanism, so that the device structure can be simplified, and the device can be reduced in size and weight, and the price can be reduced.

  The processing and function of each unit may be realized as hardware using a circuit device for each unit, or may be realized as software using an arithmetic circuit device such as a microprocessor, a personal computer, and a workstation. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a main part of a scanning transmission electron microscope (also referred to as an electron microscope in this document) including an energy filter for an element mapping device according to an embodiment of the present invention. FIG.
1A is a front view, and FIG. 1B is a view (top view) of FIG. 1A viewed from the direction of the electron beam source 1. In this figure, the electron beam source 1 to the Z contrast detector 21 are described as an electron microscope main body. Although not shown, the electron microscope main body includes a configuration for controlling scanning of an electron beam for functioning as an electron microscope. Further, a portion from the hexapole electromagnetic lens 14 to the electron beam detector 13 is described as an energy filter for an element mapping device. The signal to the arithmetic unit 23 and the signal from the arithmetic unit 23 are transmitted via the signal line 103. The input device such as a keyboard, the database 24, and the image display device 25 are connected to the arithmetic device 23. The element mapping device refers to a configuration including an arithmetic unit 23, a signal line 103, an input device and a database 24, and an image display device 25, but may also refer to a configuration including an energy filter for the element mapping device.

  As the electron beam source 1, for example, a cold cathode field emission type electron beam source can be used. An electron beam 2 generated by an electron beam source 1 is deflected by an electron beam scanning coil 3. The deflected electron beam 2 is converged on the surface of the sample 5 by the objective lens upper magnetic field 4, and forms a scanning object point 7 immediately after the objective lens lower magnetic field 6. The scanning object point 7 does not move even when the electron beam 2 is scanned on the sample surface using the electron beam scanning coil 3.

  The electron beam diffracted by the sample forms an image object point 9 before the imaging lens 8. The image point 9 moves when the electron beam 2 is scanned, but the transmitted electron (TEM) image formed at the image point 9 does not move. In the normal EELS, the image object point 9 is connected to the object point 10 by the imaging lens 8, and the EELS spectrum is measured as a virtual light source. In this embodiment, an image of the scanning object point 7 is formed on the object point 10 by the imaging lens 8 to form a virtual light source. This is because when the position of the light source moves, the aberration condition of the electron spectroscopic device 11 changes, so that it is not suitable for measurement with high energy stability such as EELS measurement.

The electron beam using the object point 10 as a virtual light source enters a fan-shaped electron spectroscope 11 installed downstream. The magnetic field of the permanent magnet constituting the electron spectroscopic device 11 forms a magnetic field space perpendicular to the plane of FIG. The electron beam incident on the electron spectroscopy device 11 is deflected by 90 °, is subjected to energy spectroscopy, and focuses on the energy dispersion surface 12. In this embodiment, the energy dispersion surface 12 is located between the electron spectroscope 11 and the electron beam detector 13 and is focused on the same place in both the energy dispersion (X) direction and the Y direction (table focus). Further, the spectrum formed on the energy dispersion surface 12 has an aberration peculiar to the electron spectroscope 11 (see FIG. 3).

FIG. 3 is a two-dimensional image of the EELS spectrum 18 formed on the electron beam detector 13. FIG. 3A shows the shape of an electron beam coming to the center and the shape of the electron beam having an energy of ± 100 eV from the electron beam projected on a detector. FIG. 3B shows the loss energy of 0.
It shows how electron beams of eV, 100 eV and 200 eV are projected on the detector. The spread shown in FIG. 3 is a secondary aberration image 26 formed by the influence of the Y focus and the secondary aberration of the apparatus. This aberration is corrected using a hexapole electromagnetic lens 14 arranged upstream of the electron spectroscopy device 11.

In the present embodiment, the spectrum formed on the energy dispersing surface 12 is about 1 eV / μm when the rotation radius of the electron beam of the electron spectroscope 11 is 100 mm. This is magnified 100 times by the magnifying magnetic field lens 15. At this time, the magnetic field of the focus adjustment electromagnetic lens 16 is adjusted so that the focus position of the expanding magnetic field lens 15 coincides with the energy dispersion surface 12. Thereby, the EELS spectrum 18 projected on the electron beam detector 13 becomes 0.01 eV / μm. If a 25 μm / channel multi-channel plate array is used as the electron beam detector 13, it will be 0.25 eV / channel. Since the detector is configured with 1024 channels, the full range is about 250 eV.

  The portion composed of the hexapole electromagnetic lens 14, the electron spectroscopic device 11, the expanding magnetic field lens 15, the focus adjusting electromagnetic lens 16, and the electron beam detector 13 of this embodiment is called an energy filter for an element mapping device. The energy filter for the element mapping device is configured so that the zero-loss electron beam comes to the center of the electron beam detector 13. The intensity of a core-loss electron beam having a loss of 250 eV or more, such as a core-loss electron beam, is measured by accelerating the core-loss electron beam with an acceleration tube 19 installed inside the electron spectroscope 11. When measuring the intensity of a core-loss electron beam that has lost 500 eV, 500 V is applied to the accelerating tube to accelerate the core-loss electrons. Thereby, the core loss electron beam to be measured can be brought to the center of the detector 13.

  The energy filter of the above-described element mapping device has a structure using a permanent magnet for the magnifying magnetic field lens 15, so that wiring for an electromagnet, a cooling mechanism for an electromagnetic lens, and the like are not required, so that the structure can be simplified and the weight of the device can be reduced. In addition, since the portion using the electromagnet is a hexapole electromagnetic lens 14 for removing bi-aberration and an electromagnetic lens 16 for focusing the magnifying lens, the influence of power supply stability is small.

The conditions necessary for performing elemental mapping in real time are that an energy loss peak can be seen and that the electron beam that has lost the same energy during measurement focuses on the same location of the electron beam detector. In this embodiment, even if the condition of the hexapole electromagnetic lens 14 changes, it hardly affects the measurement. Also, even if the magnetic field of the focus adjusting electromagnetic lens 16 of the magnifying lens changes by about ± 5 × 10 ^{−6, the} change of the focus position is about 1 μm and the magnification changes by about ± 5 × 10 ^−4. Has no effect.

  The embodiments described so far are examples of a scanning transmission electron microscope provided with an energy filter for an element mapping device using a permanent magnet. Next, an embodiment of a real-time element mapping method using this embodiment will be described.

  An example of a process for obtaining an element mapping image will be described with reference to FIG.

  Conventionally, the user (1) selects an analysis element → (2) investigates electron beam loss energy → (3) adjusts the voltage of the drift tube of the PEELS device → (4) confirms the spectrum → (5) specifies the analysis area → (6) ) Electron loss energy intensity distribution measurement → (7) Background correction and gain correction of detection means → (8) Designation of background area → (9) Background fitting function such as power low model (I = AE-r) → (10) Designation of integration area of signal intensity → (11) Display of signal intensity of designated element at measurement location on image display device → Repeat (1) to repeat for each measurement location and measurement element And an element distribution image was obtained.

In the embodiment of the present invention, the operator only needs to be involved in (1) element designation processing 201 → (4) spectrum confirmation processing 204 → (5) analysis area designation processing 205 which is measurement area designation processing. The other processes are (2) check the electron beam loss energy → (3) adjust the voltage of the drift tube of the EELS device → (6) measure the electron beam energy intensity distribution → (7) background correction and gain of the detecting means Correction → (8) Designation of background area → (9) Designation of background fitting function such as power low model (I = AE-r) →
(10) Designation of integration area of signal intensity → (11) Display of signal intensity of specified element at measurement location on image display device → Process of (1) is performed under the control of arithmetic unit 23 and the electron microscope body. Since the energy filter for the element mapping device is controlled and the measurement process is repeatedly performed for each measurement location and / or each measurement element, an element distribution image of the specified element can be obtained in real time.

  In other words, as shown in an example in FIG. 2, (1) a process 201 for specifying an analysis element which is a process for selecting an analysis element, (2) a process 202 for checking an EELS table which is a process for checking electron beam loss energy, (3) Drift tube voltage adjustment processing 203 for adjusting the drift tube voltage, (4) spectrum confirmation processing 204 for confirming the spectrum, and (5) analysis area designation as the analysis area designation processing Processing 205 is performed.

  Further, (6) the measurement processing 206 for measuring the electron beam loss energy intensity distribution is performed by repeating the following processing 207 to processing 210. First, the spectrum acquisition process 207 and the spectrum acquisition process 206 that are the processes for acquiring the spectrum may include a process of correcting the background of the electron beam detector 130 and a process of correcting the gain. (8) In the background correction 208, a process of specifying a background area and a background fitting function is performed.

In the process 209 for calculating the difference between the intensities, the integration region of the signal intensity is specified. A measurement completion determination process 210 for determining whether measurement has been completed based on whether or not all the measurement points have been measured is performed. If the measurement has not been completed (NO in the figure), the process returns to process 207. If the processing has been completed (YES in the figure), based on the result of the measurement processing 206, (11) the element mapping image display processing 211 for displaying the signal intensity of the specified element at the specified measurement location on the image display device I do.

In the conventional EELS, since the energy stability of the EELS spectrum was about ± 5 × 10 ⁻⁶ , the position of the energy loss peak during measurement was 25% as the electron beam detector 13.
Drift several channels on a multi-channel plate array of μm / channel. When the above-described embodiment is used, since the energy stability of the EELS spectrum is about ± 1 × 10 ⁻⁸ , the drift of the energy loss peak during measurement can be suppressed within one channel of the electron beam detector 13. It becomes.

  FIG. 4 shows the shape of the EELS spectrum of core loss electrons. A core loss electron is an electron that loses element-specific energy when an electron beam excites an inner shell electron of an atom.

(Two-window method)
As shown in FIG. 4A, when the core loss spectrum is measured using the range immediately before the core loss peak 27 (pre-window 28) and immediately after (post-window 29) as one window (two-window method), the width of the window It is necessary to determine the energy width between the two windows. In the present embodiment, this information is stored in the database 24 of FIG. 1 to automate this measurement operation. In the conventional EELS, each time measurement is performed, the energy stability of the spectrum due to the change of the electron optical system is a cause. Even if the user has a similar database, the user can view the spectrum and adjust the position and width of the window. Because of the need to determine, automation of the measurement is difficult.

  The database 24 holds the conditions of core loss energy (eV), window width (number of channels), and window interval (number of channels) corresponding to each element as data. A voltage corresponding to the core loss energy is applied to 19, and the window width and the window interval given by the database 24 are applied to the electron beam detector 13. The electron beam intensity obtained from the two windows is corrected for the background and gain specific to the electron beam detector 13 by the arithmetic unit 23, and then the intensity ratio of the two windows is calculated and displayed on the image display unit 25. In this case, the control signal 101 is output from the arithmetic unit 23 to the electron microscope main body via the signal line 103, and the processing is performed in conjunction with the electron beam scanning coil 3, thereby realizing the element distribution image in real time. get. According to this method, an element distribution image free from the influence of the background can be obtained in a short calculation time.

(Three-window method)
The three-window method will be described with reference to FIG. As in the two-window method described with reference to FIG. 3, the database 24 holds condition data of core loss energy (eV), window width (number of channels), and window interval (number of channels), and the user specifies a measurement element. As a result, a voltage corresponding to the core loss energy is applied to the acceleration tube 19. The data of the window width and the window interval provided by the database 24 is applied to the electron beam detector 13 (see FIG. 4B), the EELS spectrum is measured, and the background and gain unique to the detector are corrected. The electron beam intensity of the two windows (pre-1 window 30, pre-2 window 31) on the lower energy side than the core loss is calculated according to the power-low model (I = AE-r), and the background 32 of one window on the higher energy side than the core loss is calculated. Is calculated. The result obtained by subtracting the calculated background 32 from the electron beam intensity of the post window 29 on the higher energy side than the core loss is displayed on the image display device 25. This operation is performed in an interlocked manner by transmitting a control signal 101 from the arithmetic unit 23 to the electron microscope main body via the signal line 103 and controlling the electron beam scanning coil 3 of the electron microscope main body. In addition, a control signal 102 from the arithmetic unit 23 is sent to an energy filter for an element mapping device via a signal line 103 to control an optical system and a drift tube. Thereby, the intervention of the operator can be reduced, so that the element distribution image can be obtained in real time.

  This method has an advantage that a quantitative element distribution image can be obtained. For quantification, it is necessary to correct the obtained core loss intensity with the zero loss intensity and the film thickness of the sample. As will be described later, in the present embodiment, the measurement of the zero loss intensity and the measurement of the film thickness distribution image of the sample can be performed simultaneously with the measurement of the core loss intensity. And the film thickness distribution are measured, and these corrections are performed by the arithmetic unit 23 to obtain a quantified element distribution image.

As an example of the information of the core loss peak 27 included in the database 24, in the case of iron (Fe), EL2: 721 eV, EL3: 708 eV, two-window method: W1: 50 channels, ΔW: 4 channels, W2: 50 channels, 3 Window method: W1: 25 channels, ΔW12: 0 channels, W2: 25 channels, ΔW23: 2 channels, W3:
There are 50 channels. The window width (W) and interval (ΔW) may be energy widths instead of the number of channels.

(Contrast tuning)
Next, a method of acquiring a contrast tuning image will be described with reference to FIG. The plasmon loss peaks 34 related to silicon, the plasmon loss peaks 35 related to silicon nitride, and the plasmon loss peaks 36 related to silicon oxide may have different plasmon loss energies for each substance. Plasmon loss peak width is narrow, 2-5
Since it is about eV, the number of channels is about 8 to 20 on the electron beam detector. Since the energy difference between the plasmon peaks of the respective substances is small, it was indistinguishable in the conventional EELS whether the contained substances increased or decreased or the EELS spectrum drifted. In this embodiment, the drift of the EELS spectrum is small, and the peak shift is caused by the increase or decrease of the substance. Therefore, the substance can be distinguished by contrast tuning.

The plasmon loss peaks of silicon, silicon nitride, and silicon oxide are 17 eV, 19 eV, and 23 eV, respectively. The database contains plasmon peaks: Esi: 17 eV, W: 10 channels, Esin: 19 eV, W: 10 channels, Esio: 23
eV, W: Register 10 channels. The window width (W) may be an energy width instead of the number of channels.

  In this embodiment, first, the contrast tuning method is selected. Next, a detection element is specified, for example, silicon, silicon nitride, or silicon oxide. At this time, the display color is also selected (the intensity from the silicon window 38 is red, the intensity from the silicon nitride window 39 is blue, and the intensity from the silicon oxide window 40 is green). After searching the positions of the plasmon peaks of silicon, silicon nitride, and silicon oxide from the database, the voltage of the accelerating tube 22 of the electron spectroscope 11 is set to the median value of the measurement elements. Next, the window width of the measurement region is determined from the channel position of the detector corresponding to the position of the window width of the plasmon peak measurement.

  After the electron beam intensity measured in each channel is corrected for the background unique to the electron beam detector 13 and the gain, it is integrated in the designated window range. The obtained electron beam intensity is divided by the number of channels in each window to obtain an average electron beam intensity per channel. This electron beam intensity is displayed on the image display device in the shade of the color specified previously. By automatically performing this operation in conjunction with the electron beam scanning coil 3, a contrast tuning image can be obtained in real time.

  When obtaining the contrast tuning image, the zero loss intensity 37 is also measured at the same time, and the average electron beam intensity is divided by the electron beam intensity, whereby a contrast tuning image in which the change in the incident electron beam intensity is corrected can be obtained.

(Thickness mapping)
When the entire plasmon loss peak 33 is set as one plasmon window 41 and a zero loss window 42 is set at the zero loss peak 37, the plasmon lost electron beam intensity is divided by zero loss intensity + plasmon intensity (measured total electron beam intensity). Gives a value related to the thickness of the sample. By automatically performing this work in conjunction with the electron beam scanning coil 3, a film thickness mapping image can be obtained in real time.

  Film thickness mapping is important and essential information for quantifying element distribution. In this embodiment, since the core loss image and the film thickness mapping image can be obtained simultaneously by changing the voltage of the acceleration tube 19, a quantitative element mapping image can be easily obtained by the calculation in the calculation device 23. That is, the core loss intensity is the product of the film thickness of the sample, the amount of elements in the measurement region, and the electron beam scattering ability. Since the electron beam scattering ability is a constant peculiar to an element, it is necessary to divide the obtained core loss intensity by the film thickness in order to obtain the amount of the element. It is possible to measure the core loss intensity and the film thickness at each measurement point, and obtain a quantified element distribution image by dividing the core loss intensity by the film thickness by the arithmetic unit 23.

(Chip noise removal method)
Finally, the chip noise removing method will be described. Since the STEM obtains a two-dimensional image using the secondary electron detector 20, the Z contrast detector 21, the fluorescent X-ray detector 22, and the like while scanning the electron beam, various information can be obtained with high spatial resolution. However, the two-dimensional image obtained by scanning has a slightly different measured time depending on the location. When a phenomenon called chip noise, in which the incident intensity of the electron beam changes with time, occurs, the intensity of the measured information (secondary electron, transmitted electron, Z contrast, fluorescent X-ray, EELS spectrum) also changes, so that it is obtained. The problem is that it is not possible to distinguish whether the result is the effect of chip noise or information from the sample. In particular, in a STEM using a field emission electron beam source, chip noise is likely to occur.

  Focusing on the fact that the EELS spectrum can be measured while measuring the secondary electron image, the Z contrast image, and the fluorescent X-ray image using the secondary electron detector 20, the Z contrast detector 21, and the fluorescent X-ray detector 22, Chip noise was removed by using the intensity of the zero-loss electron beam as an intensity monitor of the incident electron beam.

  Simultaneously or in parallel with the measurement of the zero-loss intensity using the present embodiment (correction of the background and gain of the electron beam detector using the arithmetic unit 23), the secondary electron intensity, the Z contrast intensity, and the fluorescence Measure the X-ray intensity. By dividing the intensity of the secondary electron, the Z contrast, and the intensity of the fluorescent X-ray by the intensity of the zero-loss electron beam using the arithmetic unit 23, the change in the intensity of the incident electron beam can be removed. This operation is automatically performed in conjunction with the electron beam scanning coil 3 (that is, the electron beam is moved to the measurement point using the electron beam scanning coil 3 and measured and calculated. The electron beam is moved to the next measurement point. Controlling the apparatus to repeat the measurement, calculation, and movement of the electron beam by using the scanning coil 3) to obtain a secondary electron image, a Z contrast image, and a fluorescent X-ray image without chip noise. Become.

  A second embodiment of the present invention will be described. In the present embodiment, during the observation of the element distribution, a distribution image of a plurality of elements can be created by changing the element to be observed, or the observation position can be changed while observing the element distribution image, or the observation magnification can be changed. An example of an element mapping device will be described.

  FIG. 6 shows an energy filter and a control device 50 used in this embodiment. In the energy filter of the present embodiment, an electron beam detector 13 is provided at the position of the energy dispersion surface 12 in the energy filter of the first embodiment. Was provided downstream of the electron spectroscopy apparatus 11.

In this embodiment, the scanning transmission electron microscope (STEM) described in the first embodiment is used (see FIG. 1). The electron beam detector 13 uses a 1024-channel multi-channel plate array. The electron beam detector 13 is arranged in advance so that the zero-loss electron beam passing through the optical axis 49 of the electron spectroscopy device 11 is incident on the center channel (for example, the 501st channel).

  FIG. 7 shows a control device 50 of the element mapping device of the present embodiment. The control device 50 includes a STEM control unit 51 that controls the STEM, an energy filter control unit 52 that controls an energy filter, and a storage device that stores core loss energy (core electron loss energy), electron beam intensity, correction information, and the like of each element. 53, a calculation unit 54 for calculating the correction and the electron beam intensity ratio, and a central control unit 55 for controlling each unit.

As in the first embodiment, the storage device 53 stores acceleration voltage data corresponding to the core loss energy of each element, position information W1 of the pre-window 28, position information W2 of the post-window 29, and the pre-window 28 and the post-window 28. 29 is stored in advance. The position information W1 of the pre-window 28 is obtained from the spectrum of the post-window 29 having an energy slightly smaller than the core loss energy such that the pre-window 28 cuts out the spectrum of the energy slightly smaller than the core loss peak 27. The position and width corresponding to the channel of the electron beam detector 13 are predetermined for each element so as to cut out the core loss peak 27 and the spectrum larger than the core loss peak 27. The element mapping apparatus of the present embodiment automatically controls a different apparatus for each element by storing the above-described data for each element in the storage device 53.

  A method for obtaining a multiple element distribution image using the element mapping apparatus of the present embodiment will be described below. FIG. 8 shows the flow.

  The operator performs the initial adjustment of the STEM such as (1) setting the sample on the STEM, (2) adjusting the optical axis of the STEM, and (3) performing the initial adjustment of the energy filter. The initial adjustment of the energy filter means that the magnetic field of the electron spectrometer 11 is adjusted so that the zero-loss electron beam passes through the optical axis 49 of the electron spectrometer 11 so that the split electron beam is focused on the energy dispersion surface 12. The purpose is to adjust the magnetic field of the focusing adjustment electromagnetic lens 16 and to adjust the magnetic field of the magnifying lens 15 so that the spectrum spreads over a predetermined range of the energy dispersion surface.

  Next, the central control unit 50 controls the STEM control unit 51 and the energy filter control unit 52 to obtain (4) correction data for background correction and gain correction, and causes the storage device 53 to store the data. (5) The operator confirms the region on the sample for which the element distribution is to be obtained, and (6) first inputs the element whose distribution is to be obtained from the input device 56. In this embodiment, Fe was input.

  Then, the measurement of the electron beam intensity is started. (7) The central control unit 55 sends the acceleration voltage data 708V of Fe from the storage device 53 to the energy filter control unit 52. The energy filter control unit 52 applies an acceleration voltage 708 V corresponding to the core loss energy to the acceleration tube 19. (8) The central control unit 55 controls the STEM control unit 51 to move the electron beam to the measurement point P1 in the region where the element distribution is to be measured.

The electron beam transmitted through the sample was split by the electron spectroscope 11. Of the split electron beam,
The core loss electron beam corresponding to the core loss energy of 708 eV of Fe was incident on the 501st channel of the electron beam detector 13 along the optical axis 49 of the electron spectroscope 11.

At this time, the intensity of the electron beam incident on each channel of the electron beam detector 13 was input to the STEM control unit 51. (9) The STEM control unit 51 sets the window-related data W1 obtained from the storage device 53 (in the case of Fe, the 50th channel corresponding to the 431st to 480th channels of the electron beam detector 13), W2 (the same The spectrum S1 cut by the pre-window 28 and the host window 29 are cut based on 50 channels corresponding to the 485th to 534th channels of the ray detector 13 and ΔW (same for 4 channels of the electron beam detector 13). The output spectrum S2 is output. The spectrum S1 is the spectrum of the electron beam incident on the channels 431 to 480, that is, the spectrum in the range of 704.5 to 707 eV, and the spectrum S2 is the spectrum of the electron beam incident on the channels 485 to 534, that is, 704 to 534e.
It is a spectrum including a core loss peak 207 of 714.5 eV. The storage device 53 stores the spectrum S1 and the spectrum S2 together with the position P1 of the electron beam on the sample.

  Next, (10) the arithmetic unit 54 performs the background correction and the gain correction on the spectrum S1 and the spectrum S2 using the correction data stored in the storage device 53 in (4). (11) The arithmetic unit 54 divides the corrected spectrum S1 by the corrected spectrum S2 to obtain an electron beam intensity ratio. (12) The calculation unit 54 superimposes the intensity ratio of the measurement area and the position P on the image, changes the contrast according to the intensity ratio, and changes the color for each element, and displays the same on the display device 25. .

Until the element is changed, the central control unit 55 controls the STEM control unit 51 to move the electron beam to the next measurement point P2, and repeats (7) to (12). (13) When the operator changes the element to Cu, an acceleration voltage corresponding to the core loss energy of Cu is applied to the accelerating tube 19 in (7), and a spectrum is acquired using the window information corresponding to Cu in (9). And
(7) to (12) are repeated as in the case of Fe. Even when another element is specified, a two-dimensional element distribution image can be obtained by repeating (7) to (12) in accordance with the data stored in advance.

  According to the mapping device of the present embodiment, acceleration voltage data and window information of each element are prepared in the storage device 53 in advance, and the control device 50 immediately measures the changed element. The element to be observed can be changed during the observation, and the two-dimensional element distribution image can be immediately confirmed on the display device 24. In addition, since all the electron beams incident on the energy filter pass through the object point 10, aberration distortion in the electron spectrometer 11 can be reduced, and energy stability is good. Therefore, the drift of the electron energy loss spectrum obtained by dispersing the electron beam is reduced, and an accurate element distribution can be obtained.

  The example which measured the semiconductor element using the mapping apparatus of a present Example is shown. FIG. 9 is a two-dimensional element distribution image obtained by switching the measurement element from oxygen O => nitrogen N => oxygen O. The sample is a capacitor part of a 64 mega DRAM (Dynamic Random Access Memory), and a silicon oxide film and a silicon nitride film are used as an insulating film. Conventionally, two-dimensional distribution images of oxygen and nitrogen could be obtained independently of each other, but the positional relationship between the silicon oxide film and the silicon nitride film could not be known from these two-dimensional distribution images. However, according to this embodiment, two distributions of oxygen and nitrogen can be obtained in the same measurement region, and therefore, the positional relationship between the silicon oxide film and the silicon nitride film can be clearly defined with a high resolution of nanometer or less. it can.

  In the present embodiment, the element to be observed is changed during the observation. However, the area to be observed may be changed or the observation magnification may be changed while observing the element distribution image. As a result, a rough range in which the element exists can be known, and the field of view can be confirmed quickly.

  In order to change the element for which the distribution is to be obtained or to change the measurement region, the input device 56 may be provided with a unit for specifying the element and a unit for specifying the measurement region. For example, the display device 24 displays a button for designating various elements and a measurable region on the sample together with a two-dimensional element distribution image of the region where the measurement is completed. When changing the element, the operator designates the button of the element to be obtained, and when changing the measurement area, specifies the area to be measured.

  Alternatively, the element distribution may be obtained by measuring the spectra of a plurality of elements while fixing the measurement point without moving the position P of the electron beam. In this case, the measurement time is lengthened by the number of element types, but a two-dimensional element distribution of a plurality of elements can be obtained by scanning the measurement region of the sample only once.

  Further, in this embodiment, the window information previously stored in the storage device 53 is used in (9), but the operator observes the electron energy loss spectrum on the display device 25, and displays the pre-window 28 and the post window 29. May be determined and used as window information.

  In this embodiment, the acceleration tube 19 is used to accelerate the core-loss electron beam. However, another accelerating means such as a voltage applying device may be provided between the sample 5 and the focus adjusting lens 16.

  In the present embodiment, a multi-channel plate array is used as the electron beam detector 13, but scintillation detectors 61 to 63 corresponding to each window width may be used (see FIG. 6). In this case, a two-dimensional element distribution image is created by a three-window method. That is, the scintillation detector 61 corresponds to the pre-1 window 30, the scintillation detector 62 corresponds to the pre-2 window 31, and the scintillation detector 63 corresponds to the post window 29. The scintillation detectors 61 to 63 convert the intensity of the incident electron beam into an electric signal and input the electric signal to the STEM control unit 51.

  In (9), the STEM control unit 51 outputs the electron beam intensities I1, I2, and I3 incident on the respective detectors. The arithmetic unit 54 corrects these electron beam intensities in (10), and then (11) By applying the electron beam intensities I1 and I2 to a power law model (I = A × er), a background electron beam intensity 32 is obtained, and a difference from the electron beam intensity I3 is taken to quantitatively determine the element distribution. You can ask.

  Further, scintillation detectors having a fixed width (for example, 1 mm / channel) may be arranged instead of the scintillation detectors 61 to 63 according to each window width.

  Also, when the contrast tuning method is performed, the plasmon peak may be measured by changing the element during the observation, as in the present embodiment.

  ADVANTAGE OF THE INVENTION According to this invention, the apparatus and method which can acquire an element distribution image in real time by the analyzer which combined EELS and STEM can be provided.

FIG. 2 is a schematic configuration diagram of a main part of the first embodiment of the present invention. FIG. 4 is a diagram illustrating an example of a process for obtaining an element mapping image. (A), (b) is a figure which shows an example of the secondary aberration of an EELS spectrum. (A), (b) It is a figure which shows an example of the EELS spectrum of a core loss electron. (A), (b) It is a figure which shows an example of the EELS spectrum of a plasmon loss electron. FIG. 4 is a diagram illustrating an element mapping device according to a second embodiment of the present invention. It is a figure showing an example of a control device. FIG. 4 is a diagram illustrating an example of a process for obtaining an element mapping image. FIG. 3 is a diagram illustrating an example of a two-dimensional element distribution image of a semiconductor element.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 ... Electron beam source, 2 ... Electron beam, 3 ... Electron beam scanning coil, 4 ... Objective lens upper magnetic field, 5 ... Analytical object, 6 ... Objective lens lower magnetic field, 7 ... Scanning object point, 8 ... Imaging lens, 9: image object point, 10: object point, 11: electron spectrometer, 12: energy dispersive surface, 13: electron beam detector, 14: hexapole electromagnetic lens, 15: magnifying magnetic field lens, 16: focus adjustment electromagnetic Lens, 18 ...
EELS spectrum, 19: accelerating tube, 20: secondary electron detector, 21: Z contrast detector, 22: accelerating tube, 23: arithmetic unit, 24: database, 25: image display device, 26: secondary aberration image, 27 core loss peak, 28 pre window, 29 post window, 30 pre 1 window, 31 pre 2 window, 32 background, 33 plasmon loss peak, 34 plasmon loss peak of silicon, 35 silicon nitride Plasmon loss peak, 36 ... plasmon loss peak of silicon oxide, 37 ... zero loss intensity, 38 ... silicon window, 39 ... silicon nitride window, 40 ... silicon oxide window, 41 ... plasmon window, 42 ... zero loss window, 49 ... light Shaft, 50 ... Control device, 51 ... STEM system Parts, 52 ... energy filter control unit, 53 ... storage device,
54 arithmetic unit, 55 central control unit, 56 input device, 101, 102 control signal, 103 signal line.

Claims (19)

Based on the energy spectrum of the electron beam transmitted through the analyte and the irradiation position of the electron beam on the analyte, an element mapping apparatus that creates a distribution image of the elements contained in the analyte,
An accelerator for accelerating the electron beam transmitted through the analyte,
An electron spectrometer that performs energy spectroscopy of the electron beam transmitted through the analyte;
An electron beam detector for detecting the intensity of the split electron beam,
The electron beam that has lost specific energy corresponding to the element to be analyzed controls the accelerator so that the electron beam enters a fixed position of the electron beam detector,
An element mapping device, comprising: a control device that detects an element to be analyzed based on the intensity of an electron beam in a predetermined energy range among the detected intensities of the electron beam. The controller, a storage unit that stores in advance the value of the acceleration voltage for accelerating the electron beam having lost a specific energy, and the energy range of the electron beam used to detect the element to be analyzed,
2. The element mapping apparatus according to claim 1, further comprising: a calculation unit that detects an element to be analyzed by using an electron beam intensity in the energy range stored in advance. The storage unit stores correction data for removing the effect unique to the electron beam detector from the detected electron beam,
The element mapping apparatus according to claim 2, wherein the calculation unit corrects the electron beam detected based on the correction data. The electron beam detector has a plurality of electron beam detection units corresponding to the energy of the electron beam,
The storage unit previously stores a first energy range of an energy range including a core loss energy and a core loss peak and a second energy range of an energy range smaller than the core loss energy in an electron energy loss spectrum of an element to be analyzed. Remember,
The control device, based on the stored first energy range and the second energy range, the intensity of the first electron beam detected by the electron beam detection unit corresponding to the first energy range, Detecting the intensity of the second electron beam detected by the electron beam detector corresponding to the second energy range;
3. The element mapping apparatus according to claim 2, wherein the calculation unit divides the intensity of the first electron beam by the intensity of the second electron beam to detect an element to be analyzed. The electron beam detector has a plurality of electron beam detection units corresponding to the energy of the electron beam,
The storage unit includes a first energy range of an energy range including a core loss energy and a core loss peak, and a second energy range of two energy ranges smaller than the core loss energy, among electron energy loss spectra of an element to be analyzed. Storing the third energy range in advance,
The control device is configured to detect, based on the stored first energy range, the second energy range, and the third energy range, the first energy range detected by the electron beam detector corresponding to the first energy range. The intensity of the electron beam, the intensity of the second electron beam detected by the electron beam detector corresponding to the second energy range, and the third intensity detected by the electron beam detector corresponding to the third energy range. Detecting the intensity of the electron beam,
The calculation unit obtains a background intensity in the first energy range based on the intensity of the second electron beam and the intensity of the third electron beam, and calculates the background intensity in the first energy range. 3. The element mapping apparatus according to claim 2, wherein a difference from the background intensity is obtained to detect an element to be analyzed. The electron beam detector has a plurality of electron beam detection units corresponding to the energy of the electron beam,
The storage unit stores a plasmon energy range including a plasmon loss peak in an electron energy loss spectrum of an element to be analyzed,
The control device detects the plasmon loss intensity of the electron beam detected by the electron beam detection unit corresponding to the plasmon energy range based on the stored plasmon loss energy range,
3. The element mapping apparatus according to claim 2, wherein the calculation unit detects an element to be analyzed based on the detected plasmon loss intensity. The control device controls the accelerating tube so that the first electron beam that has lost a specific energy corresponding to the first element to be analyzed is incident on a fixed position of the electron beam detector,
Detecting the first element based on the intensity of the first electron beam in a predetermined energy range among the detected intensity of the first electron beam;
When the second element to be analyzed is input from outside,
Controlling the accelerating tube so that the second electron beam having lost the specific energy corresponding to the second element is incident on the fixed position of the electron beam detector,
The element according to claim 1, wherein the second element is detected based on the intensity of the second electron beam in a predetermined energy range among the detected intensity of the second electron beam. Mapping device.   A scanning transmission electron microscope comprising the element mapping device according to claim 1, wherein the object is irradiated with an electron beam, and the electron beam transmitted through the object is supplied to the element mapping device. Based on the energy spectrum of the electron beam transmitted through the analyte and the irradiation position of the electron beam on the analyte, the element mapping method for creating a distribution image of the elements contained in the analyte,
Irradiating the analyte with an electron beam;
Accelerating the electron beam transmitted through the analyte,
Energy spectroscopy of the electron beam transmitted through the analyte,
Detecting the intensity of the split electron beam with an electron beam detector,
Based on the intensity of the detected electron beam, detecting an element to be analyzed,
Moving the position of the electron beam to irradiate the analyte,
The accelerating step includes accelerating so that an electron beam having lost a specific energy corresponding to the element to be analyzed is incident on a fixed position of the electron beam detector,
The step of detecting the element includes the step of detecting the element to be analyzed based on the intensity of the electron beam in a predetermined energy range among the detected intensities of the electron beam. Mapping method. Changing the element to be analyzed to another element,
Accelerating the electron beam having lost the specific energy corresponding to the other element so as to be incident on the fixed position of the electron beam detector; and
Among the intensities detected when the electron beam having lost the specific energy corresponding to the other element is incident on the electron beam detector, the electron beam having a predetermined energy range corresponding to the other element 10. The element mapping method according to claim 9, further comprising the step of detecting the other element based on the intensity of the element. In the element mapping apparatus that creates a distribution image of the elements contained in the analysis target using the electron beam,
In the element mapping image representing the distribution state of the created elements, distribution states of at least two or more types of elements are represented,
An element mapping apparatus for providing an image corresponding to one type of element to a pixel constituting the element mapping. Changing the observation magnification of the element mapping of the analyte,
10. The element mapping method according to claim 9, further comprising the step of changing the amount of movement of the position of the electron beam to be different from the amount of movement of the position of the electron beam specified in the step of moving the position of the electron beam to be irradiated. In the element mapping apparatus that creates a distribution image of the elements contained in the analysis target using the electron beam,
In the element mapping image representing the distribution state of the created elements, element distribution states of at least two or more kinds of observation magnifications are represented,
An element mapping apparatus for providing an image corresponding to one kind of observation magnification to pixels constituting the element mapping. Changing the observation range of the element mapping of the analyte;
10. The element mapping method according to claim 9, further comprising the step of: moving the position of the electron beam larger than the amount of movement of the electron beam position specified in the step of moving the position of the electron beam to be irradiated. In the element mapping apparatus that creates a distribution image of the elements contained in the analysis target using the electron beam,
An element mapping apparatus for providing an element mapping image including an element distribution state at a position other than a range assumed by an observation magnification in an element mapping image representing a distribution state of the created elements.   A film thickness mapping apparatus that creates a thickness of an analyte and a distribution image in an amount proportional to the thickness based on an energy spectrum of the electron beam transmitted through the analyte and an irradiation position of the electron beam on the analyte. An accelerator for accelerating the electron beam transmitted through the analyte,
An electron spectrometer that performs energy spectroscopy of the electron beam transmitted through the analyte;
An electron beam detector having a plurality of electron beam detectors for detecting the intensity of the split electron beam,
The electron beam that has lost specific energy corresponding to the element to be analyzed controls the accelerator so that the electron beam enters a fixed position of the electron beam detector,
17. The film thickness according to claim 16, further comprising: a controller configured to detect a thickness of the analyte based on an electron beam intensity in a predetermined energy range among the detected electron beam intensities. Mapping device. The control device includes a plasmon energy range including a plasmon loss peak, and a zero-loss peak, among values of an acceleration voltage for accelerating an electron beam that has lost a specific energy, and an electron energy loss spectrum of an element to be analyzed. A storage unit that stores the zero-loss energy range in advance,
Based on the stored plasmon loss energy range and zero loss energy range, the plasmon loss intensity of the electron beam detected by the electron beam detection unit corresponding to the plasmon energy range, and the electron beam detection corresponding to the zero loss energy range The zero loss peak intensity of the electron beam detected by the part is detected,
An arithmetic unit that performs an operation of dividing the sum of the plasmon loss intensity and the zero-loss peak intensity by the zero-loss peak intensity and obtaining a logarithm of the division result;
17. The film thickness mapping apparatus according to claim 16, wherein a thickness of an analysis target is detected based on a calculation result of the calculation unit. A scanning transmission electron microscope comprising the element mapping device according to claim 16, wherein an electron beam is applied to an analysis target and an electron beam transmitted through the analysis target is supplied to the film thickness mapping device.

Images