JP7242915B2 - Charged particle beam device - Google Patents

Description

The present disclosure relates to a charged particle beam device that detects charged particles emitted from a specimen by irradiating the specimen with a charged particle beam, and in particular, to a charged particle beam emitted in a direction relative to the optical axis of the charged particle beam. The present invention relates to a charged particle beam device for detecting charged particles.

A scanning electron microscope, which is one aspect of a charged particle beam device, is a device that generates images and signal waveforms based on the detection of secondary electrons and the like obtained by irradiating a sample with an electron beam. Backscattered electrons (backscattered electrons) among the electrons emitted from the sample have angle dependence in that they are emitted in the specular reflection direction of the incident angle on the sample surface. known to be suitable. In Patent Document 1, backscattered electrons emitted in a direction with a small angle (low angle) with respect to the sample surface are guided onto the objective lens using the leakage magnetic field of the objective lens that leaks the focused magnetic field toward the sample. A scanning electron microscope is disclosed with detection by an orbital detector. Further, Patent Document 2 discloses a scanning electron microscope in which an acceleration tube for temporarily accelerating an electron beam is provided in the beam passage of an objective lens, and a backscattered electron detector is installed in the acceleration tube. Patent Document 2 describes a method for detecting secondary electrons and reflected electrons by using a phenomenon in which there is a difference between the convergence action of an objective lens on reflected electrons and the convergence action on secondary electrons.

Japanese Patent Application Laid-Open No. 2001-110351 (corresponding US Patent No. 6,555,819) Patent No. 5860642 (corresponding US Patent USP9,029,766)

Reflected electrons are generally less in quantity than secondary electrons, and may not provide sufficient signal quantity for highly accurate observation, measurement, or inspection. In order to secure a sufficient amount of signal, it is conceivable to increase the irradiation time of the electron beam and the probe current. However, it is desirable to increase the detection amount. For this reason, it is desirable to detect not only low-angle backscattered electrons but also medium-angle backscattered electrons in a relatively large amount.

A certain amount of low-angle backscattered electrons can be detected by guiding the backscattered electrons to a detector arranged on the objective lens by the leakage magnetic field of the objective lens as in Patent Document 1. The configuration limits the range of detection angles that can be covered. In order to efficiently detect backscattered electrons emitted over a wide angle range (low to medium angles), it is necessary to either enlarge the detection surface or bring the beam irradiation position where backscattered electrons are emitted closer to the detection surface. However, the configuration disclosed in Patent Document 1 is limited in high efficiency detection. Also, in Patent Document 2, since the detection surface of the detector is provided in the acceleration tube for accelerating the electron beam, there is a limit to increasing the size of the detection surface. In particular, the size of the detection surface becomes smaller than the inner diameter of the tip of the inner magnetic path of the objective lens. Electron detection efficiency decreases. In addition, since a hole is formed in the magnetic path, parasitic aberrations of the objective lens and variations in processing accuracy occur, hindering high resolution.

A charged particle beam device is proposed below for the purpose of covering a wide range of detection angles of charged particles emitted from a sample.

As one aspect for achieving the above object, a charged particle beam apparatus according to the present invention includes an objective lens for converging a charged particle beam emitted from a charged particle source, and a detector for detecting backscattered electrons emitted from a sample. It has a detector that converts it into an electrical signal and an arithmetic unit. The objective lens includes an inner magnetic path and an outer magnetic path formed to surround a coil, and the inner magnetic path is a first inner magnetic path arranged at a position facing the optical axis of the charged particle beam. and a second inner magnetic path formed to be inclined toward the optical axis of the charged particle beam and including a magnetic path tip. The detector is a space between the first inner magnetic path and an imaginary straight line passing through the tip of the magnetic path and parallel to the optical axis of the charged particle beam, It is arranged in the space closer to the sample than the upper end. The computing device produces an energy differentiated image by discriminating or classifying the electrical signals.

According to the above configuration, it is possible to efficiently detect charged particles emitted from the sample over a wide range from low angles to medium angles.

Schematic of a scanning electron microscope. FIG. 2 is a cross-sectional view showing an example of the arrangement of the signal detection surface 10; FIG. 2 is a cross-sectional view showing an example of the arrangement of the signal detection surface 10; FIG. 2 is a bottom view showing the configuration of a signal detection surface 10; FIG. 4 is a diagram showing the relationship between the number of photons generated by a scintillator and electron incident energy; The figure explaining the flow of the signal processing of a signal electron. The figure which shows the intensity|strength of an output electrical signal, and the relationship of time. FIG. 4 is a diagram showing an example of a signal detection surface 10 having two types of detection surfaces; The figure explaining the objective-lens shape of a scanning electron microscope, and the arrangement|positioning conditions of a detector. FIG. 4 is a diagram for explaining an example in which the energy of backscattered electrons changes according to the irradiation position of the beam; FIG. 5 is a diagram for explaining an image processing process for emphasizing detection signal information of desired energy based on energy discrimination of the detection signal;

One of the uses of a scanning electron microscope, which is a type of charged particle beam device, is the evaluation and measurement of semiconductor devices. In recent years, the structure of semiconductor devices has been miniaturized and has become 3D, and the evaluation values required by customers who are semiconductor device manufacturers are diversifying. In particular, as device structures become 3D, there is a need to measure the bottom dimensions of holes and grooves on semiconductor substrates with high accuracy in order to improve yield.

When the sample is irradiated with an electron beam, signal electrons with various energies are emitted in various directions due to interactions between the electrons and the sample. The signal electrons have different information about the sample depending on the emission energy and emission angle, and differential detection of the signal electrons is essential for various measurements.

In general, signal electrons emitted with an energy of 50 eV or less are called secondary electrons, and signal electrons emitted with an energy higher than that and with an energy close to that of the primary electron beam are called reflected electrons. Secondary electrons are sensitive to the surface shape and potential of the sample, and are effective for dimensional measurement of surface structures such as the pattern width of semiconductor device structures. It is impossible to escape from the hole/groove by pulling out, etc., and detection and measurement cannot be performed. Backscattered electrons, on the other hand, contain information about the composition and three-dimensional shape of the sample, and can provide information such as the 3D structure and the difference in composition between the surface and the bottom. can be used for signal detection and measurement from the bottom of the hole-and-trench structure.

In the following description, regarding the emission angle of electrons emitted from the sample, the optical axis direction of the electron beam is defined as 90 degrees. According to the emission angle of the backscattered electrons, high-angle backscattered electrons are defined near 90 degrees, medium-angle backscattered electrons are defined near 45 degrees, and low-angle backscattered electrons are defined near 0 degrees. High-angle backscattered electrons mainly contain sample composition information, medium-angle backscattered electrons contain both composition and shape information, and low-angle backscattered electrons mainly contain three-dimensional shape information of the sample. In addition, medium-angle backscattered electrons are characterized in that the number of generated electrons is greater than that of high-angle and low-angle electrons.

A scanning electron microscope that achieves both high resolution and high efficiency even when backscattered electron detection is performed will be described below. More specifically, to minimize the working distance, it is possible to detect electrons emitted in a wide range of low to medium angles without placing a detector between the objective lens and the sample. A scanning electron microscope will be described. According to the configuration described in the embodiments described later, it is possible to efficiently detect backscattered electrons with a medium angle or less while maintaining high resolution.

In the embodiments described below, for example, a charged particle source that generates a primary charged particle beam (electron beam), a magnetic field type objective lens that converges the charged particle beam on a sample, and a The tip of the inner magnetic path constituting the magnetic field type objective lens is inclined with respect to the optical axis of the primary charged particle beam, and the inside of the inner magnetic path other than the tip A charged particle beam device having a charged particle detection surface emitted from a sample and a conversion element for converting the charged particles into an electric signal will be described. The inner diameter of the charged particle detection surface is larger than the inner diameter of the tip of the inner magnetic path and not smaller than the inner diameter of the deflector.

By forming a part (tip) of the inner magnetic path to be selectively inclined, low-angle/medium-angle backscattered electrons emitted from the sample fly without colliding with the inner magnetic path. It is possible to detect low-medium angle backscattered electrons on the charged particle detection surface having an inner diameter that is larger than the inner diameter of the tip of the magnetic path and not smaller than the inner diameter of the deflector. In addition, the short focal length of the objective lens is achieved, and since an element that converts charged particles into an electric signal is provided inside the magnetic path, it is possible to reduce the size of the microscope lens barrel, thereby preventing an increase in the size of the microscope lens barrel and achieving high resolution at the same time. According to the above configuration, it is possible to achieve both high resolution and high-efficiency detection of backscattered electrons at medium and lower angles.

An overview of the scanning electron microscope will be described below with reference to the drawings.

[Example 1]
This embodiment will be described with reference to FIGS. 1 to 4. FIG. FIG. 1 is a diagram showing an outline of a scanning electron microscope. An electron source 2 is arranged inside an electron microscope lens barrel 1, which is a vacuum environment, and a primary electron beam (electron beam) emitted from the electron source 2 flies along a primary electron beam optical axis 3. . The primary electron beam is converged on the sample 8 by an objective lens composed of a coil 5, an outer magnetic path 6 surrounding the coil 5, and an inner magnetic path 7 arranged at an angle to the optical axis 3 of the primary electron beam. be. When an electric current is passed through the coil, rotationally symmetrical magnetic lines of force are generated. The magnetic lines of force pass through the inner magnetic path and the outer magnetic path, and the magnetic lines of force generate a leakage magnetic field in the lens gap (between the tip of the inner magnetic pole and the tip of the outer magnetic pole). Therefore, the primary electron beam is converged on the sample by the lens action of the leakage magnetic field.

A negative voltage is applied to the sample 8 , and the primary electrons collide with the sample with energy smaller than the energy generated by the electron source 2 . The signal electrons 9 generated from the sample by the collision of the primary electrons fly through the electron microscope lens barrel 1 according to their respective emission energies and emission angles. A signal detection surface 10 made up of a scintillator is arranged inside the objective lens. Light is guided to the element 12 .

The scintillator forming the signal detection surface 10 may be a single crystal such as YAP or YAG, a powder such as P47, or a GaN-based multi-layer thin film structure, as long as it is a substance that emits light when a charged particle beam is incident. In addition, although FIG. 1 shows the case where the light guide 11 is provided, a form in which the light/electric conversion element 12 is directly attached to the scintillator 10 without using the light guide 11 is also possible. The optical/electric conversion element 12 is composed of, for example, a photomultiplier tube (PMT), photodiode, Si-PM, or the like. The guided light is converted into an electric signal by the light/electric conversion element 12 and transmitted to a signal processing circuit 14 arranged outside the electron microscope lens barrel 1 through an output cable 13 . The electrical signal is amplified to an electrical signal with a large amplitude by the amplifier circuit 14a on the signal processing circuit 14, processed as an image contrast according to the magnitude and frequency of the electrical signal per unit time by the arithmetic circuit 14b, and is processed on the monitor 15. It is displayed as a pixel having a predetermined gradation value on it. The signal electron detection is performed while the primary electron beam is scanned over the sample 8 by the deflector 4 and an enlarged two-dimensional image of the sample surface is displayed on the monitor 15 .

The signal detection surface 10 may be arranged perpendicular to the optical axis 3 of the primary electron beam as shown in FIG. 1, may be inclined as shown in FIG. 2, or may be arranged in parallel as shown in FIG. be. The signal detection surface 10 may be flat or curved in each arrangement method. In these, the method of detecting signal electrons and image generation are performed as described above. The signal detection surface 10 is divided into a plurality of polygonal or fan-shaped regions in the angular direction as shown in FIG. 4A, or divided into rings having different diameters as shown in FIG. It is also possible to become Although FIG. 4A shows an example of four divisions, there is no limit to the number of divisions in both FIGS. 4A and 4B. Also, although FIG. 4A shows a case where there is a space between the small piece detection surfaces, a shape without this space is also possible. In these divided signal detection planes, by calculating the electrical signals obtained corresponding to each signal detection plane in the subsequent circuit, images with different contrasts such as shadow images based on the emission angle of the signal electrons can be obtained. can be obtained. 4(a) and 4(b) is an example of connection between the small piece signal detection surface 10 and the optical/electrical conversion element 12. In FIG. A method of arranging a conversion element and the like are conceivable.

In the above configuration, the deceleration (retarding) optical system that applies a negative voltage to the sample 8 and the acceleration (boosting) optical system that applies a positive voltage to the inner magnetic path 7 contribute to high resolution and high efficiency of backscattered electron detection. Effective. In the retarding optical system, the primary electron beam is decelerated by a negative voltage applied to the sample immediately before it enters the sample, and the incident angle of the converged primary electron beam increases, thereby reducing aberration. On the other hand, it acts as an accelerating electric field for the signal electrons, the secondary electrons with low energy are caused to fly along the primary electron beam optical axis 3 by the retarding electric field, and at the same time, the reflected electrons with high energy have little effect. It flies in various directions within the electron microscope lens barrel 1 without being received. Therefore, secondary electrons/reflected electrons can be separately detected by the retarding electric field, and the reflected electrons can be detected without being buried in the highly efficient secondary electrons.

Also, in the boosting optical system, by temporarily increasing the energy of the primary electrons when they enter the objective lens, the ratio of energy fluctuations in the primary electron beam can be reduced, and aberration due to the objective lens can be suppressed. At the same time, since it acts as an electric field for pulling up signal electrons from the sample, signal electrons that have collided with the lower part of the outer magnetic path 6 are pulled up inside the inner magnetic path 7, so reflected electrons in a wider angular range are detected. High efficiency can be achieved.

Next, more specific actions and effects of this embodiment will be described with reference to the drawings. FIG. 9 is a diagram for explaining the objective lens shape of the scanning electron microscope illustrated in FIG. 1 and the arrangement conditions of the detector. As illustrated in FIG. 9, the inner magnetic path of the objective lens consists of an inner magnetic path 7 (second inner magnetic path) including the leading edge of the magnetic path and a first inner magnetic path forming the other inner magnetic path. 905. The inner wall surface of the first inner magnetic path 905 (the surface forming the beam passing cylinder) is formed so as to face the optical axis 3 of the primary electron beam.

The second inner magnetic path is formed so as to be long in a direction inclined with respect to the primary electron beam optical axis 3 and inclined toward the primary electron beam optical axis 3 . Moreover, when expressed in a cross-sectional view as shown in FIG. Furthermore, the signal detection surface 10 is positioned outside (on the side of the first inner magnetic path 905) an imaginary straight line 901 defined in a direction parallel to the optical axis 3 of the primary electron beam while passing through the tip of the inner magnetic path. , in which the components of the detector are arranged. A virtual straight line 901 is defined along the opposing surface of the inner magnetic path 7 facing the primary electron beam optical axis 3 (the surface closest to the primary electron beam optical axis 3). Further, the inner diameter (beam passing aperture diameter) of the signal detection surface 10 is formed to have a larger diameter than the inner diameter of the inner magnetic path 7 .

According to such a configuration, backscattered electrons emitted at a low angle and backscattered electrons emitted at a medium angle can be detected with high efficiency. By using both the objective lens structure and the arrangement condition of the detector as described above, the detection surface can be expanded in the direction of the arrow 902 and the direction of the arrow 903 ( sample direction) can be lowered. In other words, by employing the objective lens structure as described above, a space 904 can be provided in the electron beam path of the objective lens, and by positioning the signal detection surface 10 in such a space 904, a particularly low angle can be obtained. It is possible to position the detection surface on the trajectory of the backscattered electrons emitted at the middle angle and the backscattered electrons emitted at the middle angle, and as a result, it is possible to generate an image that expresses the unevenness information of the sample surface at a high level. Become.

In order to detect electrons emitted over a wide angular range, it is necessary not only to widen the detection surface but also to bring the detection surface closer to the sample. This is because even if the detection surfaces have the same size, the angle range that can be covered by the detection surface is larger when the detection surface is closer to the sample (electron beam irradiation position). According to the configuration shown in FIG. 9, it is possible to achieve both the expansion of the detection surface in the direction of the arrow 902 and the expansion of the coverable emission angle range. As a result, the effects described above can be achieved. It becomes possible. In addition, since the detection surface can be expanded in a direction off-axis from the primary electron beam optical axis 3 instead of simply expanding the detection surface, it is possible to detect reflected electrons emitted in the middle angle direction, which has been lost in the past. It is possible to generate an image that reflects the unevenness of the sample at a higher level.

[Example 2]
This embodiment will be described with reference to FIGS. In the present embodiment, a configuration example for performing energy discrimination using the signal detection surface 10, the optical/electric conversion element 12 and the signal processing circuit 14 in the first embodiment for detecting low-medium angle backscattered electrons will be described. When the signal detection surface 10 is composed of a scintillator, the number of generated photons changes according to the energy of the signal electrons 9 incident on the signal detection surface 10 as shown in FIG. The scintillator serves as a first conversion element that converts reflected electron signals into light.

Using this property, the photo/electric conversion element 12 converts the number of photons generated by the scintillator into an electric signal, and the arithmetic circuit 14 reads the output value of the electric signal to perform energy discrimination. FIG. 6 shows a schematic diagram from signal electron detection to image generation. When the signal electrons 9 generated from the sample 8 collide with the signal detection surface 10, the number of photons corresponding to the energy of the signal electrons 9 is emitted. The emitted photons 16 are guided to a light guide (not shown), converted into an output electrical signal 17 corresponding to the number of photons by the optical/electrical conversion element 12, the output electrical signal 17 is amplified by the amplifier circuit 14a, and an amplified output electrical signal 18 is obtained. becomes. An electric signal is extracted in accordance with the output threshold value set by the arithmetic circuit 14b, and an image gradation value is created at the frequency per unit time of the extracted electric signal 19 and transmitted to the monitor 15, thereby performing energy discrimination. image is generated.

FIG. 7 shows a relationship diagram between the intensity of the amplified output electrical signal 18 and time. The post-amplification output electrical signal 18 is generated as pulses having various output values. Selective extraction provides energy discrimination. Energy discrimination enables partial enhancement of the observation area, and various measurements are achieved.

As exemplified in FIG. 10, when the surface 1001 and the bottom surface 1002 of the hole pattern are irradiated with the beam under the same conditions, even if electrons having energy E2 are reflected from each, the reflected electrons 1004 reflected from the bottom surface 1002 are reflected from the sample. As compared with the backscattered electrons 1003 emitted from the surface 1001, the energy decreases (E1=E2−ΔE) by penetrating part of the . Furthermore, a conversion element (second conversion element) such as Si-PM can generate an electrical signal corresponding to the number of photons reflecting energy information. , it is possible to generate an image in which a specific part of the pattern is emphasized.

FIG. 11 is a diagram for explaining the principle. As described with reference to FIGS. 5 and 10, when the number of photons is n when the energy of the backscattered electrons is E2, and when the number of photons is m when the energy is E1, both are divided by a predetermined threshold value (Th). Identify. As illustrated in FIG. 11, by extracting a signal equal to or higher than a predetermined threshold, it is possible to selectively extract a region in which the backscattered electron energy is E2 within the field of view. Most of the backscattered electrons with energy E2 are emitted from the sample surface 1001, and information on the sample surface 1001 is strongly reflected in the image generated based on the detection of the backscattered electrons with energy E2.

The signal waveform (B) excluding backscattered electron signals having other energies is an image that particularly strongly reflects the sample surface information. On the other hand, since the image generated based on the detection of backscattered electrons with energy E1 strongly reflects the information of the bottom surface 1002, the signal (A) strongly reflecting the information of the bottom surface 1002 indicates the sample surface. By subtracting the signal (B), it is possible to generate an image in which the bottom surface 1002 is emphasized.

FIG. 11 describes an example in which signals are discriminated into two by a single threshold (Th). For example, a three-dimensional structure including at least three patterns of different heights, upper layer, middle layer, and lower layer, is evaluated. In some cases, as the pattern becomes deeper, the degree of attenuation of the backscattered electron energy also increases. By providing (Th2), subtraction processing may be performed to extract a layer to be particularly emphasized. In addition, in the example of FIG. 11, an example of generating an image in which signals on the upper layer side are emphasized by excluding signals below the threshold (Th) has been described. , a process for emphasizing the information on the relatively lower layer side may be performed.

By executing the processing as described above by the arithmetic circuit 14b (processor), it is possible to perform energy discrimination by arithmetic operation without using an optical element such as an energy filter or a spectrometer arranged in a vacuum region. Become.

Although only high and low energies have been described in this embodiment, it is also possible to extract an electrical signal having an output value within a certain region, and high-pass, low-pass, and band-pass are possible for the energy of backscattered electrons. .

There are also a plurality of means for setting the energy region to be acquired. For example, a region of signal electronic energy to be acquired is selected in advance, and only electrical signals having output values within that range are counted and displayed on the monitor. Alternatively, all output values are recorded for each pixel, and after primary electronic scanning is completed, an energy region is selected and an image is generated from electrical signals having output values within that range.

As the light/electric conversion element 12, it is desirable to use a photodiode (PD (especially avalanche photodiode: APD)) or Si-PM (silicon photomultiplier), which is a semiconductor type element with a small Fano factor. These elements have small output variations, and can reflect the number of incident photons in the output value of an electrical signal. On the other hand, the photomultiplier tube (PMT) of the light/electric conversion element 12 generally used in electron microscopes has large output fluctuations and generates an electric signal having an output value independent of the number of incident photons. do not have.

When configured with these elements, energy discrimination is possible without using other equipment such as energy filters and spectroscopes, so the advantage is that it is easier to configure than other detectors that can discriminate energy. have.

[Example 3]
This embodiment will be described with reference to FIG. FIG. 8 shows a bottom view of a detection surface in which the signal detection surface 10 is composed of scintillators having different diameters. The signal detection surface 10 is composed of rings (20, 21) with different diameters of scintillators having different emission wavelengths and emission amounts. The number of divisions can be three or more within an effective range. When spectroscopy or photon counting is performed using the light/electric conversion element 12, it is possible to discriminate the emission angle from the detection surface position corresponding to the detected wavelength/signal amount.

In Embodiment 1, an example of a configuration in which the light/electric conversion element 12 corresponding to each signal detection surface 10 divided into a ring shape is provided is shown. It shows that the output angle is discriminated by changing the characteristics.

DESCRIPTION OF SYMBOLS 1... Electron microscope lens barrel, 2... Electron source, 3... Primary electron beam optical axis, 4... Deflector, 5... Coil, 6... Outside magnetic path, 7... Inside magnetic path, 8... Sample, 9... Signal electron, DESCRIPTION OF SYMBOLS 10... Signal detection surface 11... Light guide 12... Light/electric conversion element 13... Output cable 14... Signal processing circuit 14a... Amplifier circuit 14b... Calculation circuit 15... Monitor 16... Emission photon 17 Output electric signal 18 Amplified output electric signal 19 Extracted electric signal 20 Outer ring-shaped signal detection surface 21 Inner ring-shaped signal detection surface

Claims (18)

A charged particle beam apparatus comprising an objective lens for focusing a charged particle beam emitted from a charged particle source, a detector for detecting backscattered electrons emitted from a sample and converting them into electrical signals, and an arithmetic unit,
The objective lens includes an inner magnetic path and an outer magnetic path formed to surround a coil, and the inner magnetic path is a first inner magnetic path arranged at a position facing the optical axis of the charged particle beam. and a second inner magnetic path formed to be inclined toward the optical axis of the charged particle beam and including a tip of the magnetic path,
The detector is a space between the first inner magnetic path and an imaginary straight line passing through the tip of the magnetic path and parallel to the optical axis of the charged particle beam, arranged in the space on the sample side from the upper end,
The detector has a detection surface that detects the backscattered electrons, and a conversion element that converts light obtained by detecting the backscattered electrons on the detection surface into the electrical signal,
The charged particle beam, wherein the arithmetic unit generates an energy-discriminative backscattered electron image by selectively extracting an electrical signal having a predetermined output value from the electrical signal. Device. In claim 1,
The detector has a light guide member that guides the light to the conversion element,
The light guide member is arranged in a space between the first inner magnetic path and the imaginary straight line, which is closer to the sample than an upper end of the first inner magnetic path. charged particle beam device. In claim 1 ,
A charged particle beam apparatus according to claim 1, wherein the energy-discriminated backscattered electron image is an image in which backscattered electrons having a predetermined energy value or energy range are selectively reflected. In claim 1 ,
A charged particle beam apparatus according to claim 1, wherein the energy-discriminated backscattered electron image is an image in which surface information or bottom surface information of a pattern is selectively reflected. 5. In claim 4, the arithmetic unit selectively selects an electrical signal having a predetermined output value from the electrical signals based on a first threshold value determined for discriminating between the first layer and the second layer of the pattern. a charged particle beam apparatus for generating a backscattered electron image in which information in either the first layer or the second layer is emphasized by performing a process of extracting a second layer. In claim 1 ,
A charged particle beam apparatus, wherein the detection surface is a scintillator. In claim 6,
A charged particle beam apparatus, wherein the conversion element is a silicon photomultiplier. In claim 6,
A charged particle beam apparatus, wherein the conversion element is an avalanche photodiode. In claim 3 ,
The arithmetic device counts only the electrical signals having the predetermined output value based on the predetermined energy value or energy region designated from the user interface, and an image generated based on the count value or the count value. is displayed on the user interface. In claim 1 ,
The charged particle beam apparatus, wherein the arithmetic unit selectively extracts the electrical signal having the predetermined output value by comparing the electrical signal with one or more predetermined threshold values. In claim 7,
A charged particle beam apparatus, wherein the detector detects backscattered electrons emitted from the specimen at an emission angle including at least 45 degrees with respect to the optical axis of the charged particle beam. In claim 11,
A charged particle beam apparatus, wherein the detector further detects backscattered electrons emitted from the sample at an emission angle of 90 degrees with respect to the optical axis of the charged particle beam. In claim 5,
The arithmetic unit selectively extracts an electrical signal having a predetermined output value from the electrical signals based on a second threshold value determined for discriminating between the third layer and the second layer of the pattern. generating a backscattered electron image that enhances information in any one of the first, second and third layers by performing
A charged particle beam device characterized by: In claim 6,
comprising a deflector that deflects the charged particle beam;
A charged particle beam apparatus, wherein the scintillator and the conversion element are arranged closer to the specimen than the deflector. In claim 1 ,
A charged particle beam apparatus, wherein a positive voltage for accelerating the charged particle beam is applied to the second inner magnetic path. 16. A charged particle beam apparatus according to claim 15, wherein a negative voltage is applied to said sample for decelerating said charged particle beam. In claim 14,
A charged particle beam apparatus, wherein the inner diameter of the scintillator is larger than the inner diameter of the tip of the magnetic path. In claim 17,
A charged particle beam apparatus, wherein the inner diameter of the scintillator is equal to or larger than the inner diameter of the deflector.

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