JPH08148109A - Focusing in charged particle beam device and its device - Google Patents

Abstract

PURPOSE: To obtain a focusing method and its device in charged particles beam in which, even in a specimen having a characteristic portion in linear or island form, high-precision focusing is possible. CONSTITUTION: Linear scanning of electron beam on a specimen 4 is first made in direction, and then in y direction. A detection signal obtained by electron beam scanning is differentiated individually in a signal differentiation unit 15. Then, the differential signal is reversed in absolute value in an absolute value reversal unit 16. The absolute-value reversed signal is then integrated in an integration unit 17. In a peak value comparison unit 18, quantities of the peak values in the two types of integration waveforms are mutually compared, and so, a scanning direction giving a peak or larger quantity is selected and this result of selection is provided to a computer 5. Focusing operation on the basis of this selection is thus started in the computer 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focusing method and apparatus for a charged particle beam apparatus such as a scanning electron microscope capable of automatically focusing a charged particle beam.

[0002]

2. Description of the Related Art A scanning electron microscope has an automatic focusing function. In this focusing, the excitation of the focusing lens is changed stepwise, and a predetermined region of the sample is scanned with the electron beam in each excitation state, that is, in each focusing state of the electron beam. Electrons and backscattered electrons are detected, and detection signals are integrated for each focusing state. Then, the integrated values of the detection signals in each focusing state are compared, the focusing state when the maximum value is obtained is determined to be the focus position, and the excitation of the focusing lens is set in that state.

[0003]

By the way, in focusing, if unevenness is present over the entire scanning region of the sample, the change in the signal obtained with the scanning of the electron beam is large and the precision is high. Focusing can be performed. However, for samples such as IC patterns,
There are many linear patterns, and if the electron beam is scanned along the linear pattern during focusing, the electron beam does not traverse the concavo-convex portion, and the intensity of the obtained signal becomes small. As a result, the difference in the integrated value of the detection signal used for focusing becomes small depending on each focusing state of the electron beam, and the accuracy of focusing falls.

FIG. 1 is a diagram for explaining the above problems in more detail. FIG. 1 shows an IC pattern. FIG. 1A shows a vertical pattern IC pattern, FIG. 1B shows a horizontal pattern IC pattern, and FIG. 1C shows a partial pattern on the sample surface. Shows an island pattern in which is formed.

In the figure, a portion indicated by Q is a region where a convex and elongated pattern is formed, and a portion indicated by R is a region where, for example, a circular hole is formed. FIG.
In the case of (a), when the electron beam is scanned in the X direction, the electron beam crosses the boundary portion of the uneven pattern, so that the secondary electron detection signal and the backscattered electron detection signal of high intensity are accompanied by the scanning of the electron beam. can get.

On the other hand, when the electron beam is scanned in the Y direction,
Since the electron beam does not traverse the uneven portion, the intensity of the detection signal becomes extremely weak. In the case of FIG. 1B, the detection signal is weak in scanning the electron beam in the X direction, and the intensity of the detection signal is strong in scanning the electron beam in the Y direction.

In the case of FIG. 1 (c), since the characteristic part on the sample is limited to a part, if the entire surface of the sample is scanned, the change in the signal amount at each excitation step of the objective lens is small, Difficult to focus accurately.

The present invention has been made in view of the above points, and an object thereof is to perform focusing with high accuracy even in a sample in which a characteristic portion is present linearly or only partially. It is to realize a method and device for focusing in a charged particle beam that can be performed.

[0009]

According to a first aspect of the present invention, there is provided a focusing method in a charged particle beam apparatus, wherein the intensity of a focusing lens for focusing a charged particle beam on a sample is changed stepwise, and the change is made. Each time, the irradiation position of the charged particle beam on the sample is scanned, the strength of the optimum focusing lens is detected based on the signal obtained by this scanning, and the focusing lens strength is set to that strength. In a focusing method in a charged particle beam device, a charged particle beam is scanned in a first direction before the focusing operation, the signals obtained with this scanning are integrated, and then the first
The charged particle beam is scanned in a direction different from the above direction, the signals obtained by this scanning are integrated, and the scanning direction in which a larger integrated intensity is obtained is selected based on the two kinds of integrated results. It is characterized in that the focusing operation is performed depending on the scanning direction.

In the focusing in the charged particle beam apparatus according to the first aspect of the invention, the charged particle beam is scanned in the first direction before the focusing operation, and the signals obtained by this scanning are integrated. Then, the charged particle beam is scanned in a direction different from the first direction, the signals obtained by this scanning are integrated, and a larger integrated intensity is obtained based on the two types of integrated results. Select. Then, a predetermined focusing operation is performed according to the selected scanning direction.

According to a second aspect of the present invention, there is provided a focusing method in a charged particle beam apparatus, wherein the intensity of a focusing lens for focusing a charged particle beam on a sample is changed stepwise, and each time the change is made, the focus on the sample is changed. The focal point of the charged particle beam device that scans the irradiation position of the charged particle beam, detects the intensity of the optimum focusing lens based on the signal obtained with this scanning, and sets the focusing lens intensity to that intensity. In the focusing method, before the focusing operation, the charged particle beam is scanned in the first direction, the signals obtained with this scanning are integrated for each scanning position, and the peak profile corresponding to each scanning position is obtained. Then, the charged particle beam is scanned in a direction different from the first direction, the signals obtained by this scanning are integrated for each scanning position, and the peak plot corresponding to each scanning position is obtained. Give the file, two select a specific scanning method based on the peak size and peak profile distribution width of the peak profile, it is characterized in that to perform the focusing operation on the selected scanning method.

In focusing in the charged particle beam apparatus according to the second aspect of the present invention, before the focusing operation, the charged particle beam is scanned in the first direction and the signals obtained by this scanning are integrated. To obtain a peak profile, then scan the charged particle beam in a direction different from the first direction, and integrate the signals obtained by this scanning to obtain a peak profile. Select a particular scanning method based on size and peak profile distribution width. Then, a predetermined focusing operation is performed by the selected scanning method.

According to another aspect of the present invention, there is provided a focusing device in a charged particle beam device, comprising: a focusing lens for focusing a charged particle beam on a sample; and means for changing the intensity of the focusing lens in a stepwise manner. Scanning means for two-dimensionally scanning the irradiation position of the charged particle beam on the sample and detection for detecting the signal obtained by irradiation of the charged particle beam on the sample each time the focusing lens intensity changes stepwise. And a focusing device in a charged particle beam device, the focusing lens having a focusing unit and means for setting the focusing lens intensity based on a signal from a detector corresponding to each step change of the focusing lens intensity. Means for scanning the sample in different first and second directions, and a signal obtained by scanning the charged particle beam in the first and second directions. Storage means for storing been accumulated to,
A means for selecting one of the scanning directions based on the signal intensity stored in the storage means is provided, and the focusing operation is performed in the selected scanning direction.

In focusing in the charged particle beam apparatus according to the third aspect of the present invention, before the focusing operation, the charged particle beam is scanned in the first direction and the signals obtained by this scanning are integrated. Then, the charged particle beam is scanned in a direction different from the first direction, the signals obtained by this scanning are integrated, and a larger integrated intensity is obtained based on the two types of integrated results. Select. Then, a predetermined focusing operation is performed according to the selected scanning direction.

According to another aspect of the present invention, there is provided a focusing device for a charged particle beam device, comprising: a focusing lens for focusing a charged particle beam on a sample; and means for changing the intensity of the focusing lens in a stepwise manner. Scanning means for two-dimensionally scanning the irradiation position of the charged particle beam on the sample and detection for detecting the signal obtained by irradiation of the charged particle beam on the sample each time the focusing lens intensity changes stepwise. And a focusing device in a charged particle beam device, the focusing lens having a focusing unit and means for setting the focusing lens intensity based on a signal from a detector corresponding to each step change of the focusing lens intensity. Means for scanning the sample in different first and second directions, and a signal obtained by scanning the charged particle beam in the first and second directions. It is equipped with a storage unit that stores the peak profile accumulated for each scanning position and a unit that selects a specific scanning method based on the peak profile stored in the storage unit. The feature is that a matching operation is performed.

In focusing in the charged particle beam system according to the invention of claim 4, before the focusing operation, the charged particle beam is scanned in the first direction, and the signals obtained by this scanning are integrated. To obtain a peak profile, then scan the charged particle beam in a direction different from the first direction, and integrate the signals obtained by this scanning to obtain a peak profile. Select a particular scanning method based on size and peak profile distribution width. Then, a predetermined focusing operation is performed by the selected scanning method.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 2 shows an example of a scanning electron microscope according to the present invention. In this embodiment,
This is effective for a sample in which a characteristic pattern is linearly formed. In the figure, reference numeral 1 denotes an electron gun, and an electron beam EB generated from the electron gun 1 is finely focused on a sample 4 by a focusing lens 2 and an objective lens (final stage focusing lens) 3.

Excitation current is supplied to the objective lens 3 from the computer 5 through the objective lens control unit 6.
Further, the electron beam EB is deflected by the deflector 7,
The irradiation position of the electron beam on the sample 4 is scanned. From the computer 5 to the electron beam deflection unit 8,
The scanning signal is supplied via the amplifier 9. Further, 10 is a dynamic focus lens, and this lens 10
The computer 5 is supplied with a dynamic focus lens current via the dynamic focus lens control unit 11.

Secondary electrons generated by irradiating the sample 4 with the electron beam are detected by the secondary electron detector 12. The detection signal of the detector 12 is amplified by the amplifier 13 and then supplied to the cumulative addition unit 14. The cumulative addition unit 14 performs cumulative addition of the signals detected based on the repeated scanning of the electron beam based on the signal from the electron beam deflection unit 8.

The signal from the cumulative addition unit 14 is supplied to the signal differentiating unit 15 to be differentiated. The signal from the signal differentiating unit 15 is the absolute value inverting unit 16
Is supplied to the integration unit 17 via and is subjected to integration processing.
The output signal of the integration unit 17 is the peak value comparison unit 1
8 is supplied. The operation of such a configuration will be described below.

When observing a normal secondary electron image, the computer 5 controls the electron beam deflection unit 8 and supplies a predetermined two-dimensional scanning signal from this unit 8 to the deflector 7. As a result, an arbitrary two-dimensional area on the sample 4 is raster-scanned by the electron beam EB. Secondary electrons generated by irradiating the sample 4 with the electron beam are detected by the detector 12. The detection signal is supplied via an amplifier 13 to a cathode ray tube (not shown) synchronized with the scanning signal to the deflector 5, and a secondary electron image of an arbitrary region of the sample is displayed on the cathode ray tube.

Next, the operation of determining the scanning direction before the automatic focusing operation of the electron beam will be described. First, the sample 4 is set at an arbitrary observation position in order to perform automatic focusing. When the computer 5 is instructed of the focusing mode, the computer 5 sets a reference lens value to 3 in the objective lens via the objective lens control unit 6.

Further, the computer 5 sets a dynamic focus value for data sampling in the dynamic focus lens 10 via the dynamic focus lens control unit 11.

Next, the computer 5 causes the electron beam deflection unit 8 to generate a scanning signal for linearly scanning the electron beam on the sample 4. This scanning signal is supplied to the deflector 7 via the amplifier 9. As a result, a specific linear portion on the sample 4 is repeatedly scanned with the electron beam in the X direction, for example. Secondary electrons are generated from the sample 4 based on the scanning of the electron beam on the sample 4. The generated secondary electrons are detected by the secondary electron detector 12.

The detection signal of the secondary electron detector 12 is the amplifier 1
After being amplified by 3, it is supplied to the cumulative addition unit 14. In the cumulative addition unit 14, the detection signal is stored in the memory address corresponding to the scanning coordinate position of the electron beam based on the reference signal from the electron beam deflection unit 8, and the detection signal based on the scanning of the same straight line region on the sample is stored. Cumulative addition is performed on the memory address. This operation improves the SN ratio of the detection signal.

The linear scanning of the electron beam on the sample 4 is first performed in the X direction Sx and then in the Y direction Sy on the sample 4 as shown in FIG. By scanning with the electron beam in the X direction, a detection signal as shown in FIG. 4A is obtained, and by scanning with the electron beam in the Y direction, the detection signal shown in FIG. 4B is obtained. In FIGS. 4A and 4B, the vertical axis represents the detection signal intensity and the horizontal axis represents the scanning coordinate position. This Figure 4
The detection signals shown in (a) and (b) are cumulatively added by the cumulative addition unit 14, respectively.

The detection signals in the X and Y directions, which have been cumulatively added by the cumulative addition unit 14, are differentiated individually by the signal differentiation unit 15. Further, the differential signal is subjected to absolute value inversion processing in the absolute value inversion unit 16.
The absolute value inversion processing signal is subjected to integration processing in the integration unit 17.

FIG. 5 shows the above-mentioned processing result for the signal detected by the electron beam scanning in the X direction. FIG. 5A shows a signal which is detected and cumulatively added, and this signal is differentiated and becomes a signal shown by a solid line in FIG. 5B. The signal subjected to the differential processing is subjected to the absolute value inversion processing in the absolute value inversion unit 16. By this processing, the negative signal among the differential signals is inverted as shown by the dotted line in FIG. 5 (b). The absolute value-inverted signal is integrated by the integration unit 17, and the signal shown in FIG. 5C is obtained. This FIG. 5 (c)
The final integrated value of is the peak value.

Each processing described above is performed by two kinds of scanning in the X direction and scanning in the Y direction. As a result, as shown in FIG.
As shown in (d), two types of integration results are obtained. FIG.
(C) is an integration result based on X-direction scanning, and its peak value is Px. FIG. 4D shows an integration result based on Y-direction scanning, and its peak value is Py. The peak value comparison unit 18 compares the magnitudes of the two peak values Px and Py, selects the scanning direction in which a large peak value is obtained,
Notify the computer 5 of the selection result. Computer 5
Starts the focusing operation based on the selected scanning direction.

In the actual focusing operation, the computer 5 controls the dynamic focus lens control unit 11 and the electron beam deflection unit 8. As a result, the dynamic focus lens control unit 11 supplies the stepwise changing exciting current to the dynamic focus lens 10, and the electron beam deflecting unit 8 changes the stepwise exciting current 2 to a predetermined area of the sample 2 each time.
A scanning signal for performing dimensional scanning is supplied to the deflector 7.

The two-dimensional scanning at this time is performed by raster-scanning the electron beam in a specific direction (X direction in the above-mentioned case) determined by the selection operation of the scanning in the X direction and the Y direction.

The secondary electron signal detected by the detector 12 in the focus state by the stepwise exciting current is amplified by the amplifier 13 and then supplied to the signal differentiating unit 15. After the negative signal is inverted in the absolute value inversion unit 16, the differentiated signal is subjected to integration processing in the integration unit 17. This integration processing is performed on the signal based on the two-dimensional scanning of the electron beam once for each excitation step of the objective lens 3. The integrated value of the integrating unit 17 is supplied to the peak value comparing unit 18.

The peak value comparison unit 17 stores the integrated value of the integration unit 16 for each excitation step of the dynamic focus lens 10. The peak value comparison unit 17 detects the excitation intensity of the objective lens 3 at the peak of the change in the signal amount integrated value, and the value is detected by the computer 5.
Supply to.

The computer 5 controls the objective lens control unit 8 to set the objective lens 3 to the excitation intensity obtained by adding the excitation intensity of the dynamic focus lens at the peak, and the focusing operation is performed in this way. In this focusing operation, the electron beam scan is performed across a linear pattern on the sample, so the intensity of the signal detected with the electron beam scan is large, and the focus position is determined based on the large signal. Can be detected, and as a result, accurate focusing can be performed.

FIG. 6 shows another embodiment of the present invention. The same parts as those of the scanning electron microscope of FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted. In this embodiment,
The value integrated by the integration unit 17 is supplied to the peak profile storage unit 19. The peak profile storage unit 19 stores the value integrated by the integration unit 17 for each scanning position of electron beam scanning.

The peak profile stored in the pook profile storage unit 19 is supplied to the profile value comparison unit 20 and the distribution value calculation unit 21 for obtaining the distribution width of the peak profile. The values of the profile value comparison unit 20 and the distribution value calculation unit 21 are supplied to the computer 5.

With such a configuration, the peak profile storage unit 19 stores the peak profile corresponding to each scanning position. FIG. 7A shows a sample in which a continuous pattern is formed in the Y direction. When this sample is scanned in the X direction, the peak profile shown in FIG. 7B is obtained. Also, when scanning in the Y direction,
The peak profile shown in FIG. 7C is obtained.

FIG. 8A shows a sample in which a continuous pattern is formed in the X direction. When the sample is scanned in the X direction, the peak profile shown in FIG. 8B is obtained. To be Further, when scanning is performed in the Y direction, FIG.
The peak profile shown in (c) is obtained.

FIG. 9A shows a sample in which an island pattern is formed on a part of the sample, and when the sample is scanned in the X direction, the peak profile shown in FIG. 9B is obtained. can get. Further, when scanning is performed in the Y direction, FIG.
The peak profile shown in is obtained.

The peak profile value stored in the peak profile storage unit 19 is supplied to the profile value comparison unit 20 to compare the size of the peak profile by the scanning in the X direction and the scanning in the Y direction. The comparison result is supplied to the computer 5.

Further, the peak profile storage unit 1
The distribution width of the peak profile stored in 9 is obtained by the distribution value calculation unit 21, and the value is supplied to the computer 5.

The computer 5 determines which type the pattern on the sample is, according to the peak size and the distribution width of the peak profile from the peak profile value comparison unit 19 and the distribution value calculation unit 21. For example, X
If the peak size due to the scanning of the electron beam in the direction is large and the peak size due to the scanning in the Y direction is small, and the distribution of the peak profile is small in both scans, it is determined that the pattern is a continuous pattern in the Y direction. To do.

When the peak size due to the scanning of the electron beam in the Y direction is small and the peak size due to the scanning in the Y direction is large, and the peak profile distributions are small in both scans, the X direction. Judge as a continuous pattern.

Further, the size of the peak due to the scanning of the electron beam in the Y direction and the X direction is arbitrary, but if the distribution of the peak profile is large in both scans, it is judged as an island pattern.

The computer 5 determines the scanning method at the time of focusing according to the type of the pattern on the sample determined in the above step, and executes the focusing operation according to this scanning method. That is, the computer 5 controls the dynamic focus lens control unit 11 and the electron beam deflection unit 8.

As a result, the dynamic focus lens control unit 11 controls the dynamic focus lens 10
To the electron beam deflecting unit 8, and the electron beam deflection unit 8 changes the stepwise exciting current each time.
A scanning signal for performing two-dimensional scanning of a predetermined area of the sample is supplied to the deflector 7. The two-dimensional scanning at this time is performed by raster-scanning the electron beam in the X direction if the pattern on the sample is a continuous pattern in the Y direction.

If the pattern on the sample is a continuous pattern in the X direction, it is performed by raster scanning the electron beam in the Y direction. If the pattern on the sample is an island pattern, the electron beam is scanned only in the scanning range in which the characteristic portion exists. For example, in FIG. 9A, the scanning range y1 to y2 in the Y direction is scanned in the X direction. In this case, the scanning range in the Y direction is y1 to y2, X
It is preferable to limit the directional scanning range to x1 to x2.

The electron beam is scanned during the focusing operation as described above. In this focusing operation, when the linear pattern is formed, the scanning of the electron beam is performed on the sample. Since it is performed across the linear pattern of, the intensity of the signal detected with the scanning of the electron beam is large, and the in-focus position can be detected based on the large signal, and as a result, accurate focusing is performed. be able to. Further, in the case of an island pattern in which the characteristic portion exists only in a part of the sample, the electron beam scanning is performed only in the characteristic portion, so that the signal detected along with the scanning of the electron beam The intensity is high, and the in-focus position can be detected based on a large signal, and as a result, accurate focusing can be performed.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to these embodiments. For example, although secondary electrons are detected, reflected electrons may be detected. Further, in the embodiment, the electron beam is previously scanned in two directions of X and Y and either one of the two directions is selected. However, the electron beam is scanned in three or more directions, and the scanning in each direction is the largest. The direction in which the signal strength is obtained may be set as the scanning direction in the actual focusing.

Further, although the excitation of the dynamic focus lens is changed during the focusing operation, the excitation of the objective lens may be changed stepwise without using the dynamic focus lens. Furthermore, when focusing, the detection signals are integrated for each scanning and the integrated signals are compared to obtain the optimum focus position. However, the maximum amplitude value (peak-to-peak value) of the detection signal is detected. It may be done. Furthermore, in the embodiment, the electron beam apparatus such as the scanning electron microscope has been described as an example, but the present invention can be applied to the ion beam apparatus.

[0051]

As described above, according to the first aspect of the present invention.
In the focusing in the charged particle beam device based on 3 and 3, before the focusing operation, the charged particle beam is scanned in the first direction, the signals obtained by the scanning are integrated, and then the first operation is performed. The charged particle beam is scanned in a direction different from the above direction, the signals obtained by this scanning are integrated, and the scanning direction in which a larger integrated intensity is obtained is selected based on the two kinds of integrated results. Then, a predetermined focusing operation is performed according to the selected scanning direction.

As a result, in the case where the concavo-convex pattern on the sample is lined up in a straight line, the charged particle beam is scanned in the scanning direction in which the signal intensity becomes large, so that more accurate automatic focusing should be performed. You can

Further, in the focusing in the charged particle beam apparatus according to the second and fourth aspects of the invention, the charged particle beam is scanned in the first direction before the focusing operation, and it is obtained in association with this scanning. The signals obtained are integrated to obtain a peak profile, then the charged particle beam is scanned in a direction different from the first direction, and the signals obtained by this scanning are integrated to obtain a peak profile. A specific scanning method is selected based on the peak size of the peak profile and the peak profile distribution width. Then, the predetermined focusing operation is performed by the selected scanning method.

As a result, when the concavo-convex pattern on the sample is lined up in a straight line, or in the case of an island pattern in which the characteristic part exists only in a part of the sample, the charging is performed in the scanning direction where the signal intensity becomes large. Since the particle beam is scanned or the charged particle beam is scanned only in the characteristic portion, more accurate automatic focusing can be performed.

[Brief description of drawings]

FIG. 1 is a diagram showing an IC pattern.

FIG. 2 is a diagram showing an example of a scanning electron microscope according to the present invention.

FIG. 3 is a diagram for explaining a pre-scanning direction for determining a scanning direction.

FIG. 4 is a diagram showing a detection signal obtained by scanning in the X and Y directions and an integration result of the detection signal.

FIG. 5 is a diagram showing each signal processing waveform.

FIG. 6 is a diagram showing another example of a scanning electron microscope according to the present invention.

FIG. 7 is a diagram showing a Y continuous pattern and a peak profile associated with electron beam scanning in X and Y directions.

FIG. 8 is a diagram showing an X continuous pattern and a peak profile associated with electron beam scanning in X and Y directions.

FIG. 9 is a diagram showing an island pattern and a peak profile associated with electron beam scanning in the X and Y directions.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electron gun 2 Focusing lens 3 Objective lens 4 Sample 5 Computer 6 Objective lens control unit 7 Deflector 8 Electron beam deflection unit 9 Amplifier 10 Dynamic focus lens 11 Dynamic focus lens unit 12 Secondary electron detector 13 Amplifier 14 Cumulative addition unit 15 Signal differentiation unit 16 Absolute value inversion unit 17 Integration unit 18 Peak value comparison unit

Claims (4)

[Claims] 1. The intensity of a focusing lens for focusing a charged particle beam on a sample is changed stepwise, and the irradiation position of the charged particle beam on the sample is scanned each time the intensity is changed.
Based on the signal obtained along with this scanning, the intensity of the optimum focusing lens is detected, and in the focusing method in the charged particle beam device in which the focusing lens intensity is set to that intensity, before the focusing operation. , The charged particle beam is scanned in the first direction, the signals obtained by this scanning are integrated, then the charged particle beam is scanned in a direction different from the first direction, and the signal obtained by this scanning is acquired. Charged particle beam, characterized in that the selected signals are integrated, a scanning direction in which a larger integrated intensity is obtained is selected based on two kinds of integrated results, and the focusing operation is performed according to the selected scanning direction. Focusing method in device. 2. The intensity of a focusing lens for focusing the charged particle beam on the sample is changed stepwise, and the irradiation position of the charged particle beam on the sample is scanned each time the intensity is changed.
Based on the signal obtained along with this scanning, the intensity of the optimum focusing lens is detected, and in the focusing method in the charged particle beam device in which the focusing lens intensity is set to that intensity, before the focusing operation. , The charged particle beam is scanned in the first direction, the signals obtained by this scanning are integrated for each scanning position, the peak profile corresponding to each scanning position is obtained, and then, different from the first direction. The charged particle beam is scanned in different directions, and the signals obtained by this scanning are integrated for each scanning position to obtain a peak profile corresponding to each scanning position. Focusing in a charged particle beam device, characterized in that a specific scanning method is selected based on the distribution width, and the focusing operation is performed by the selected scanning method. Method. 3. A focusing lens for focusing the charged particle beam on the sample, a means for changing the intensity of the focusing lens in a stepwise manner, and a charge on the sample for each stepwise change of the focusing lens intensity. A scanning means for two-dimensionally scanning the irradiation position of the particle beam, a detector for detecting a signal obtained by irradiating the sample with the charged particle beam, and detection according to each stepwise change of the focusing lens intensity. And a means for setting the intensity of the focusing lens on the basis of a signal from the instrument in a focusing device in a charged particle beam device, wherein the charged particle beam is scanned over the sample in different first and second directions. Based on the signal intensity stored in the storage means, and a storage means for storing the signals obtained by scanning the charged particle beam in the first and second directions. And a means for selecting any one of the scanning directions, and the focusing operation is performed in the selected scanning direction. 4. A focusing lens for focusing the charged particle beam on the sample, a means for changing the intensity of the focusing lens in a stepwise manner, and a charge on the sample for each stepwise change of the focusing lens intensity. A scanning means for two-dimensionally scanning the irradiation position of the particle beam, a detector for detecting a signal obtained by irradiating the sample with the charged particle beam, and detection according to each stepwise change of the focusing lens intensity. And a means for setting the intensity of the focusing lens on the basis of a signal from the instrument in a focusing device in a charged particle beam device, wherein the charged particle beam is scanned over the sample in different first and second directions. Scanning means for performing the scanning, and storage means for storing signals obtained by scanning the charged particle beam in the first and second directions for each scanning position to store a peak profile. And a means for selecting a specific scanning method based on the peak profile stored in the storage means, and a focusing operation is performed by the selected scanning method. Focusing device.