JP5191714B2 - Automatic correction method for electron beam apparatus, computer program, recording medium, and electron beam apparatus - Google Patents

Description

  The present invention relates to an electron beam apparatus automatic correction method, a computer program, a recording medium, and an electron beam apparatus, and more particularly to an electron beam for irradiating an observation target region on a sample with an electron beam to form a sample image by electrons generated from the sample. The present invention relates to an apparatus automatic adjustment method, a computer program, a recording medium, and an electron beam apparatus.

  Conventionally, as an electron beam device, an electron beam is scanned by a deflector and irradiated to a sample such as a semiconductor substrate or a photomask by an objective lens to detect charged particles such as a secondary electron beam generated from the sample. There is known a substrate observing apparatus that acquires a sample image based on information of a synchronization signal generator for scanning, and evaluates a semiconductor substrate or the like from the sample image.

In such an electron beam apparatus, if the lens alignment correction, astigmatism correction, and focus adjustment are not performed correctly, the accuracy of the obtained image deteriorates. For this reason, conventionally, in an electron beam apparatus, astigmatism correction and focus adjustment (autofocus) are automatically adjusted.
When performing automatic adjustment, select a target to be adjusted, that is, an alignment coil that performs alignment correction, a stig coil that performs astigmatism correction, and a predetermined coil and lens from an objective lens that performs focus adjustment. By changing the voltage applied to the object, the sample is scanned to acquire an image, and adjustment items selected based on the quality of the image are adjusted.

Examples of the automatic adjustment described above include the following. Patent Document 1 discloses a focusing lens for finely focusing an electron beam irradiated on a sample, deflection means for two-dimensionally scanning the electron beam in the X direction and the Y direction on the sample, and an electron beam. In an electron beam apparatus comprising an XY astigmatism correction device arranged in a passage, a step of scanning an electron beam two-dimensionally on a sample and integrating a signal obtained by the scanning, the electron beam Step of scanning a large number of times while changing the excitation intensity of the objective lens, focus shift between the two peak centers of the integration value change curve in the presence of astigmatism due to a change in the excitation intensity of the objective lens A step of obtaining an amount D, and reading out an astigmatism correction value corresponding to the obtained deviation amount D among a plurality of astigmatism correction values supplied to an astigmatism correction device stored in advance according to the deviation amount D Step, each astigmatic correction value supplied to the astigmatism correction device each time to scan the electron beam, the step of integrating the signal obtained by the scanning, the change curve of the integral value with changes in astigmatism correction value Describes an astigmatism correction method in an electron beam apparatus comprising the step of setting an astigmatism correction value at the peak of the astigmatism correction apparatus.

Patent Document 2 discloses a step of scanning an electron beam deflected by a deflecting unit to detect a charged particle generated on a sample having an arbitrary shape to obtain a sample image. A step of obtaining the sharpness of the edge component in a predetermined direction of a sample shape having an arbitrary shape with respect to a sample image obtained while changing the angle, and further, changing the excitation intensity of the objective lens and the obtained sharpness for each predetermined direction The step of calculating the peak position corresponding to the excitation intensity of the objective lens in each predetermined direction based on the degree, and whether to correct the corresponding astigmatism correction coil by the distance of the peak position in the predetermined direction. What is provided with the step to judge is described.
Japanese Patent No. 312541 JP 2007-109408 A

  However, in order to automatically perform alignment correction, it is necessary to use an image of a sample on which a pattern for alignment correction is formed because of the necessity of measuring the amount of misalignment, and such a pattern is formed. There is a problem that alignment correction cannot be performed automatically for samples that are not.

  Therefore, the present invention provides an automatic adjustment method for an electron beam apparatus that automatically performs alignment correction when alignment correction can be performed automatically even if the sample is not particularly provided with a pattern for alignment correction. Objective.

In the present invention, the above problem can be solved by the following means. The invention according to claim 1 sets the excitation of the objective lens to a predetermined plurality of different values, drives the deflection means with a predetermined deflection value, and scans the observation area of the sample on which the pattern is displayed with an electron beam, A pattern image data acquisition step of detecting charged particles generated from the sample and acquiring a plurality of pattern image data corresponding to the excitation state of the objective lens, and a change in excitation of the objective lens based on the plurality of pattern image data Obtained by a shift amount obtaining step for obtaining a shift amount of the observation region in the sample, a correction suitability determining step for judging whether the pattern image data is suitable for correction of lens alignment in the observation region, and a shift amount obtaining step. A correction execution determination step for determining whether or not it is necessary to execute lens alignment correction based on the shift amount; Includes a correction amount calculating step of calculating an alignment correction amount from preparative amounts, and an alignment correction step of performing an alignment correction based on said alignment correction amount, the sample data acquisition step, by projection processing the acquired pattern image data Including a process of generating profile data and using the profile data as pattern image data, wherein the shift amount obtaining step obtains an optimum focus value from the sharpness of the obtained plurality of pattern image data, and the obtained optimum focus value Thus, a plurality of sample images for determining the shift amount are determined, and a profile weighting process is included in the pattern of the sample image to be used .

According to a second aspect of the present invention, there is provided an automatic alignment adjustment by the automatic adjustment method for an electron beam apparatus according to the first aspect, and an automatic correction and focus of astigmatism using pattern image data obtained by the automatic alignment adjustment. And performing automatic adjustment of the alignment, automatic correction of astigmatism, and automatic correction of focus until all automatic corrections are unnecessary. This is an automatic adjustment method for an electron beam apparatus.

According to a third aspect of the invention, in the automatic correction method of the electron beam apparatus according to the second aspect, when the automatic correction of the alignment is executed, only the automatic correction of the focus is performed, and the automatic correction of the alignment is unnecessary. When it is determined that there is, the automatic correction of astigmatism and the automatic correction of focus are sequentially performed based on the acquired plurality of pattern image data .

According to a fourth aspect of the present invention, there is provided a computer program characterized in that the automatic correction method for an electron beam apparatus according to any one of the first to third aspects is executed by a computer .

The invention according to claim 5 is a recording medium in which the program according to claim 4 is stored.

The invention according to claim 6 sets the excitation of the objective lens to a predetermined plurality of different values, drives the deflection means with a predetermined deflection value, scans the observation area of the sample on which the pattern is displayed, with an electron beam, Pattern image data acquisition means for detecting charged particles generated from the laser beam and acquiring a plurality of pattern image data corresponding to the excitation state of the objective lens, and a change in excitation of the objective lens based on the plurality of pattern image data The shift amount acquisition means for obtaining the shift amount of the observation region in the sample, the correction suitability determination means for determining whether the pattern image data is suitable for correction of lens alignment in the observation region, and the shift amount acquisition step. Correction execution determining means for determining whether it is necessary to execute lens alignment correction based on the shift amount; A correction amount calculating means for obtaining a correction amount; and an alignment correction means for performing alignment correction based on the alignment correction amount. The sample data acquiring means generates profile data by projecting the acquired pattern image data. Then, the profile data is processed as pattern image data, and the shift amount acquisition unit obtains an optimum focus value from the sharpness of the obtained plurality of pattern image data, and the shift amount is obtained from the obtained optimum focus value. The electron beam apparatus is characterized in that a plurality of sample images for obtaining the above are determined and profile weighting processing is performed on the pattern of the sample image to be used.

  According to the present invention, in the electron beam apparatus, excitation of the objective lens is set to a plurality of predetermined different values, and the observation area of the sample on which the pattern is displayed by driving the deflecting means with the predetermined deflection value is an electron beam. Scanning, detecting charged particles generated from the sample, obtaining a plurality of pattern image data corresponding to the excitation state of the objective lens, and the sample based on the excitation change of the objective lens based on the plurality of pattern image data Determining whether or not the pattern image data is suitable for correction of lens alignment, and determining whether or not it is necessary to perform lens alignment correction based on the shift amount obtained in the shift amount acquisition step. Determination, an alignment correction amount is obtained from the shift amount, and alignment correction is performed based on the alignment correction amount. Even if the sample does not have a pattern for alignment correction, it can be determined whether alignment correction can be performed automatically based on the pattern of the sample, and alignment correction can be performed automatically. There is an effect that it can be performed well.

  Hereinafter, an example in which an electron beam apparatus according to an embodiment of the present invention is applied to a scanning electron microscope will be described. FIG. 1 is a schematic diagram showing a schematic configuration of a scanning electron microscope. As shown in FIG. 1, the scanning electron microscope 10 converts an electron beam 41 generated from an electron beam source 12 in the upper part of the lens barrel 11 into an alignment coil 13 (first correction means) and a stig coil 14 (second correction means). ), The focus is adjusted by the objective lens coil 15 (focus adjustment means), and the sample is scanned. Charged particles 42 such as secondary electrons and reflected electrons generated from the sample 21 are detected by a detector 30, and a sample image is displayed and observed by image display means such as a monitor (not shown). Normally, the aberration of an electron beam incident on the objective lens can be minimized by aligning with the lens axis.

  In the scanning electron microscope 10 according to the present example, three-stage corrections of alignment correction, astigmatism correction, and focus correction are performed in the order described. These corrections are performed by executing a program by a computer built in the scanning electron microscope 10 and controlling each unit. The program is stored in a medium such as an FD or CD and installed in a computer HD, ROM or the like and executed.

  Next, the overall procedure of the correction will be described. FIG. 2 is a flowchart showing an overall procedure for adjusting each correction coil in the scanning microscope. In this example, when correction is started, first, a predetermined region of the sample to be observed is scanned while changing the focus to obtain a plurality of images (ST1). Here, a pattern is formed on the sample, and a pattern image arranged in the observation region is formed on the plurality of acquired images. Here, the electron beam desirably has a probe diameter as small as possible on the sample, and at the same time, the probe shape is desirably close to a perfect circle.

  Next, it is determined whether this pattern is suitable for alignment correction, that is, whether alignment correction is possible (ST2). Whether or not alignment correction is possible depends on the state of the pattern as will be described later. In this example, as will be described later, the state of the entire image and the state of the pattern are determined twice. If alignment correction is possible (Yes in ST2), the alignment coil 13 is automatically adjusted to execute alignment correction (ST3, ST4). If alignment correction is not possible (No in ST2), the following The process proceeds to astigmatism correction (ST5 to ST7) as correction.

  When performing alignment correction, it is determined whether alignment correction is necessary (ST3). If the alignment is set to such an extent that alignment correction is unnecessary, alignment correction is not performed and the process proceeds to the next astigmatism correction process (No in ST3). If alignment correction is necessary, that is, if the axis is shifted beyond a predetermined value (Yes in ST3), alignment correction is executed (ST4). When alignment correction is performed, the process proceeds to the next focus correction (ST8 to ST10) without performing astigmatism correction. In this case, the focus correction is performed without performing the astigmatism correction because if the alignment correction and the astigmatism correction are continuously performed, both corrections influence each other and the correction state does not converge. For this reason, in this example, astigmatism correction is performed when alignment correction is not performed, that is, when alignment correction cannot be performed (No in ST2) and when alignment correction is not necessary (No in ST3).

  In astigmatism correction, it is first determined whether or not astigmatism correction is possible from the acquired images of a plurality of patterns (ST5). Whether or not astigmatism correction is possible is determined by the state of the pattern. When astigmatism correction is possible (Yes in ST5), the stig coil 14 is automatically adjusted to perform astigmatism correction (ST6 and ST7). When astigmatism correction cannot be performed (No in ST5), the process proceeds to the next focus correction (ST8 to ST10).

  When performing astigmatism correction, it is first determined whether or not astigmatism correction is necessary (ST6). If astigmatism is corrected to the extent that astigmatism correction is unnecessary, astigmatism correction is not performed and the process proceeds to the next focus correction process (No in ST6). If there is astigmatism that requires astigmatism correction (Yes in ST6), astigmatism correction is executed (ST7). After the astigmatism correction is completed, the process proceeds to focus correction (ST8 to ST10). For correcting astigmatism, the method described in Japanese Patent Application Laid-Open No. 2007-109408 proposed by the inventors can be used.

  In focus correction, first, it is determined whether focus correction is possible from the acquired images of a plurality of patterns (ST8). Whether or not focus correction is possible is determined by the state of the pattern. When focus correction is possible (Yes in ST8), the objective lens coil 15 is automatically adjusted and focus correction (ST9) is executed, and focus correction is performed. If this is not possible (No in ST8), the series of automatic correction processing is terminated.

  After focus correction is performed (ST9), it is determined whether alignment correction or astigmatism correction is performed before focus correction. If alignment correction or astigmatism correction is performed, a plurality of refocus required A single image is photographed (ST1), the above-described processing is executed, and these processing (ST1 to ST10) is repeated until all corrections of alignment correction, astigmatism correction, and focus correction are completed.

  Hereinafter, alignment correction executed by the automatic adjustment method of the electron beam apparatus according to the embodiment will be described. First, the basic concept of alignment correction will be described. FIG. 3 is a schematic diagram showing a state of photographing area shift during autofocus processing.

  Usually, the beam is not incident on the originally expected axis due to the machining accuracy of the pole pieces of the upper and lower poles. For this reason, by applying a deflection magnetic field or a deflection electric field to the alignment coil installed above the objective lens, it can be made incident on the two-dimensional optimum alignment position.

  Further, in order to confirm whether or not the lens alignment has been correctly adjusted, it can be confirmed by changing the focus from the just focus to the front and back, so that the object on the sample does not move. That is, the autofocus function provided in the scanning electron microscope 10 is activated, and the sample is photographed with the excitation of the objective lens coil 15 changed. Accordingly, it is possible to determine and correct whether or not to adjust the lens alignment from a plurality of images whose focus has been changed.

  In a state where the lens alignment is deviated (FIG. 3A), when the focus is changed, that is, when the excitation of the objective lens coil 15 is changed, the positional deviation of the pattern (A1, A2 in FIG. 3A). Occurs. On the other hand, in a state where the lens alignment is not shifted (FIG. 3B), even if the focus is changed, the pattern does not shift (A in FIG. 3B). The present invention uses this phenomenon to detect the amount of misalignment and correct the alignment.

  Next, an alignment correction procedure according to this example will be described. Judgment and correction processing for determining whether or not to adjust the lens alignment from a plurality of images with different focus acquired at the time of autofocus processing are calculated according to the following procedure. FIG. 4 is a flowchart showing the alignment correction procedure. First, each image data with different focus is acquired and stored at the time of autofocus (ST11). At this time, the data can be stored as a part of the projection processing, or the entire image can be stored. Next, an optimum focus value is obtained from the sharpness of the image (ST12). At this time, the presence or absence of a pattern is determined (ST13). This determination is the first determination in the alignment suitability determination (ST2).

  If it is determined that there is no pattern (No in ST13), the process is terminated as not suitable for alignment correction. If it is determined that there is a pattern (Yes in ST13), the obtained optimum focus value is A plurality of pattern shift amount calculation images are determined (ST14). Then, the weighting process of the profile to be used is performed (ST15). Then, a second determination is made as to whether it is suitable for alignment correction from the processed profile. This determination is performed based on whether the pattern can detect the alignment correction amount (ST16).

  If this alignment correction cannot be performed (No in ST16), the alignment correction ends. If alignment correction can be performed (Yes in ST16), the pattern shift amount is calculated (ST17), the alignment correction amount is further calculated (ST18), and it is determined whether alignment correction is necessary (ST19). If there is (Yes in ST19), automatic alignment correction (ST20) is executed, and if alignment correction is unnecessary, that is, if alignment is ready (No in ST19), the alignment correction ends.

  Each process will be described below. First, acquisition of each image data with different focus (ST11) will be described. In this example, profiles obtained by projecting a part of each of a plurality of images with different focus obtained during autofocus are stored. When projection processing is performed in this way, it is possible to adopt a method such as acquiring an image in a lattice shape in accordance with the rotation angle of the electron beam, or extracting a portion having a larger pattern amount than CAD data.

  FIG. 5 is a diagram showing profile data acquired from a plurality of images with different focus. As shown in FIG. 5A, a plurality of image data for images with different focus are obtained according to the focus state. In this example, profile data of a 3 × 3 grid area is acquired for each obtained image data. For example, as shown in FIG. 5B, the brightness of the image data at each position is acquired at three positions in the vertical and horizontal directions, and profile data at each position (FIGS. 5C and 5D) is acquired. The profile data acquisition area is not limited to the grid area and can be set as appropriate.

  In this way, by using profile data, it is possible to greatly reduce the amount of storage devices such as a memory and an HDD, and to speed up the processing, as compared with the case of holding a plurality of original image data. If the target image is small and images with different focus can be stored, the entire image may be stored.

Next, the process (ST12) for obtaining the optimum focus value from the sharpness of the image will be described.
In this example, the profile acquired earlier is saved, and at the same time, the sharpness of each profile is obtained. From the obtained sharpness, it is determined whether or not a pattern exists. If it is determined that a pattern exists, an optimum focus value is obtained. The determination of the presence / absence of the pattern is the first determination in the determination (ST2) as to whether the lens alignment can be corrected. As described above, since it is determined whether or not alignment correction is possible based on the presence or absence of a pattern, if there is no pattern in the sample, the execution of alignment correction is stopped without performing the following processing. It is possible to continue the processing quickly without performing.

  In order to determine whether or not there is a pattern from this image (ST13), for example, it is determined whether or not the correlation coefficient when approximated based on the sharpness of each image is a certain value or more. Similarly, the optimum focus value can be calculated by an approximate value based on the sharpness of each image.

  Next, a process (ST14) for determining a plurality of pattern shift amount calculation images from the obtained optimum focus value will be described. Here, the pattern shift amount calculation image is determined from the optimum focus obtained by the above-described processing. A plurality of images whose focus shift amounts are close to the obtained optimum focus are extracted. FIG. 6 is a schematic diagram showing a plurality of images for obtaining the optimum focus value. In this example, seven images from image F1 to image 7 are acquired.

  Here, two images that are shifted by a predetermined amount or more are selected from the two images sandwiching the obtained optimum focus value. For example, when the obtained optimum focus value is close to the focus value of the image F4, the profiles of the image F3 and the image F5 sandwiching the image F4 are compared. When the optimum focus is between the image F3 and the image F4, the image F3 and the image F4 are compared. By selecting an image with a close focus shift amount in this way, it is possible to extract a pattern shift amount with high accuracy. Here, since the profile changes depending on the shift amount from the optimum focus, it is desirable that the images to be compared have a close shift amount from the optimum focus.

Next, profile weighting processing (ST15) to be used will be described. Depending on the profile position, there may be defective data such as when there is no image on the data. Therefore, a profile with a small amount of information needs to be excluded or weighted. That is, using the image closest to the optimum focus value obtained in step ST14, the information amount of each profile is calculated and weighted.
This weighting is performed by the following procedure.

  Weighting is performed by multiplying the value in each profile by a weighting coefficient W. In this case, DD = σm / σa is obtained by setting σa as the average of the variance of a plurality of profiles and σm as the variance of the target profile. When D is equal to or smaller than the threshold value, W = 0, and when equal to or larger than the threshold value, W = 1 is performed.

  In this process, it is also determined whether there is a pattern that can be aligned (ST16). That is, if the portion where the weighting coefficient W of the target profile is greater than a certain value, it is determined that alignment correction is possible because there is a pattern. And shift to the next astigmatism correction process (No in ST2, ST5). The weighting process is not limited to the above-described one, and the weighting process can be omitted.

  Next, calculation of the pattern shift amount (ST17) and determination of whether correction is necessary (ST18) will be described. In this example, the shift amount is calculated for each profile at the same position of the image to be compared with the pattern shift amount obtained in step ST14.

  FIG. 7 is a schematic diagram showing image data to be compared. For example, the profile Fa (t) at the horizontal top position of the image Fa shown in FIG. 7A is compared with the profile Fb (t) at the horizontal top position of the image Fb shown in FIG.

This comparison is performed as follows, for example. When two profiles Fa (t) and Fb (t) are compared, for example, both profiles are compared within a predetermined value (2c). FIG. 8 shows processing in similarity determination processing of two profiles, (a) is a schematic diagram showing a start state of similarity acquisition, and (b) is a schematic diagram showing an end state of similarity acquisition. .
First, for comparison, two profiles are between regions [0-1], Fa (t) is [0- (w-2c)], and Fb (t) is [(c)-(w- c)] to be distributed. Then, while fixing Fb (t) and shifting from the state where the starting point of Fa (t) is 0 (FIG. 8 (a)) to 2c ((FIG. 8b)), The part where the similarity S (t) is maximum is obtained by comparison. Sn (t) is obtained according to the following equation (1), and a position t at which the similarity S (t) is maximum is obtained from the profiles Fa (t) and Fb (t). Here, w is the width of the profile, and c is an invalid area for matching described above.

... Formula (1)

  Then, in order to improve the accuracy of t obtained here, a deviation amount D is calculated by quadratic approximation or the like using data of S (t−k) to S (t + k) in the vicinity with t as the center (k is Any constant).

This is repeated for each profile, and a horizontal shift amount X and a vertical shift amount Y are obtained. FIG. 9 is a schematic diagram showing the shift amount acquisition position in each direction of the image. For example, when the scan rotation is 0 ° and the profile is acquired in a 3 × 3 lattice pattern, the horizontal distances of the shift amounts obtained are D _H1 , D _H2 , D _H3 , and the vertical distances are D _V1 , D _V2 , When _DV3 is set (see FIG. 9), the horizontal shift amount X and the vertical shift amount Y can be calculated from the weighting coefficient W based on the following equation (2).
here,
n _H : number of horizontal profiles adopted for calculation n _V : number of vertical profiles adopted for calculation

... Formula (2)

Next, based on the obtained shift amount (X, Y), the amount of movement of the image per focus count is obtained. Using the obtained image pixel size P (size per pixel), autofocus focus step value F _s , height correction coefficient h calculated from the obtained focus value, and depth of focus coefficient, the equation (3 ) To calculate a vector (X ′, Y ′) indicating the amount of movement of the image per focus count.

... Formula (3)

Then, based on the acquired image rotation angle θ and coil attachment deviation angle α, (X ′, Y ′) is corrected for the rotation angle, the calculation result is corrected with the gain and the offset, and the correction value of the alignment coil is calculated. Calculate (ST18).
here,
(L _X , L _Y ): current lens alignment value (G _LX , G _LY ): lens alignment correction gain value (O _LX , O _LY ): lens alignment correction offset value, corrected lens alignment value (ΔL _X , ΔL _Y ) is obtained based on the equation (4).

... Formula (4)

Then, it is determined whether alignment correction is necessary (ST19). This determination is made based on whether (ΔLx ² + ΔLy ² ) ^1/2 is within the threshold value. If the value is within the threshold value, it is correct to the extent that alignment is allowed. If the value is equal to or greater than the threshold value, it is determined that the alignment is out of order and correction is necessary. If it is outside the threshold value, ΔLx and ΔLy are added to the current value of the alignment coil, respectively, and lens alignment correction is automatically executed (ST19).

  Thereby, the alignment correction of the scanning electron microscope 10 is completed, and other corrections, that is, astigmatism correction and focus correction, are performed according to a predetermined procedure according to the procedure shown in FIG. Observation will be performed.

  As described above, according to the automatic correction method of the electron beam apparatus according to the present example, whether or not alignment correction can be automatically performed according to the pattern of the sample, even if the sample is not particularly provided with the pattern for alignment correction. Determination and alignment correction can be automatically performed, and automatic adjustment of the electron beam apparatus can be efficiently performed.

It is a schematic diagram which shows schematic structure of a scanning electron microscope. It is a flowchart which shows the whole procedure of each correction coil adjustment in a scanning microscope. FIG. 6 is a schematic diagram illustrating a state of photographing area shift during autofocus processing. It is a flowchart which shows the procedure of the correction | amendment of alignment. It is a figure which shows the profile data acquired from several images from which a focus differs. It is a schematic diagram which shows the several image for obtaining the optimal focus value. It is a schematic diagram which shows the image data used as comparison object. It is a schematic diagram which shows the process in the similarity determination process of two profiles. It is a schematic diagram which shows the deviation | shift amount acquisition position in each direction of an image.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Scanning electron microscope 11 Lens tube 12 Electron beam source 13 Alignment coil 14 Stig coil 15 Objective lens coil 21 Sample 30 Detector 41 Electron beam 42 Charged particle

Claims (6)

The excitation of the objective lens is set to a plurality of different predetermined values, the deflection means is driven with a predetermined deflection value, and the observation area of the sample on which the pattern is displayed is scanned with an electron beam to detect charged particles generated from the sample A pattern image data acquisition step for acquiring a plurality of pattern image data corresponding to the excitation state of the objective lens;
A shift amount obtaining step for obtaining a shift amount of an observation region in the sample due to a change in excitation of the objective lens based on the plurality of pattern image data;
A correction suitability determination step for determining whether the pattern image data is suitable for correction of lens alignment in the observation region;
Correction execution determination step for determining whether it is necessary to execute lens alignment correction based on the shift amount obtained in the shift amount acquisition step;
A correction amount calculating step for obtaining an alignment correction amount from the shift amount;
An alignment correction step for performing alignment correction based on the alignment correction amount;
With
The sample data acquisition step includes
Including processing to generate profile data by projecting the acquired pattern image data, and using the profile data as pattern image data,
The shift amount acquisition step includes:
Obtain an optimum focus value from the sharpness of the acquired pattern image data,
From the obtained optimum focus value, determine multiple sample images for obtaining the shift amount,
An automatic adjustment method for an electron beam apparatus, comprising a profile weighting process for a pattern of a sample image to be used . At least one of automatic adjustment of alignment by the automatic adjustment method of an electron beam apparatus according to claim 1 and automatic correction of astigmatism and automatic correction of focus using pattern image data obtained by the automatic adjustment of alignment. Automatic adjustment of the electron beam apparatus , wherein the automatic adjustment of the alignment, the automatic correction of the astigmatism, and the automatic correction of the focus are repeatedly performed until all the automatic corrections are unnecessary. Method. When the automatic correction of the alignment is performed, only the automatic correction of the focus is performed, and when it is determined that the automatic correction of the alignment is unnecessary, the astigmatism is determined based on the plurality of acquired pattern image data. 3. The automatic correction method for an electron beam apparatus according to claim 2, wherein automatic correction and automatic focus correction are sequentially performed .   A computer program for executing the automatic correction method for an electron beam apparatus according to any one of claims 1 to 3 by a computer.   A recording medium storing the program according to claim 4.   The excitation of the objective lens is set to a plurality of different predetermined values, the deflection means is driven with a predetermined deflection value, and the observation area of the sample on which the pattern is displayed is scanned with an electron beam to detect charged particles generated from the sample A pattern image data acquisition means for acquiring a plurality of pattern image data corresponding to the excitation state of the objective lens;
  A shift amount obtaining means for obtaining a shift amount of an observation region in the sample due to a change in excitation of the objective lens based on the plurality of pattern image data;
  Correction suitability determination means for determining whether the pattern image data is suitable for correction of lens alignment in the observation region;
  Correction execution determination means for determining whether it is necessary to execute lens alignment correction based on the shift amount obtained in the shift amount acquisition step;
  A correction amount calculating means for obtaining an alignment correction amount from the shift amount;
  Alignment correction means for performing alignment correction based on the alignment correction amount;
  With
  The sample data acquisition means includes
  The obtained pattern image data is projected to generate profile data, and this profile data is processed as pattern image data.
  The shift amount acquisition means includes
  Obtain an optimum focus value from the sharpness of the acquired pattern image data,
  From the obtained optimum focus value, determine multiple sample images for obtaining the shift amount,
  An electron beam apparatus characterized by performing profile weighting on a pattern of a sample image to be used.