JP2003022771A - Particle beam device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a particle beam device and an adjusting method of the particle beam equipment, which enable to perform adjustment of a light axis easily, even if the state of the particle beam changes. SOLUTION: It has an operation means to calculate deflection amount of an alignment deflector which performs axial adjustment to an object lens and the like, memorizes two or more calculating methods for calculating the above deflection amount for this operation means, and has a selection means to choose the calculating method concerned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged particle beam apparatus, and more particularly to a charged particle beam apparatus suitable for stably obtaining a high resolution image by correcting a deviation of an optical axis of a charged particle optical system.

[0002]

2. Description of the Related Art In a charged particle beam apparatus typified by a scanning electron microscope, desired information (for example, a sample image) is obtained from a sample by scanning a finely focused charged particle beam on the sample. In such a charged particle beam device, when the optical axis is displaced from the lens, lens aberration occurs and the resolution of the sample image deteriorates. Therefore, highly accurate axis adjustment is necessary to obtain a sample image with high resolution. Is. Therefore, in the conventional axis adjustment, the exciting current of the objective lens is periodically changed and the operating conditions of the deflector (aligner) for axis adjustment are manually adjusted so as to minimize the movement at that time. Further, as a technique for automatically performing such adjustment, there is a technique disclosed in Japanese Patent Laid-Open No. 2000-195453. According to this description, there is disclosed a technique of changing the excitation set value of the alignment coil based on the transition of the electron beam irradiation position which changes between the two excitation conditions of the objective lens. Further, Japanese Patent Application Laid-Open No. 2000-331637 discloses a technique for performing focus correction based on the detection of a positional deviation between two electron microscope images obtained under different optical conditions.

If the astigmatism corrector for correcting the astigmatism of the charged particle beam is deviated from the center, the field of view moves when adjusting the astigmatism, making the adjustment difficult. Therefore, another aligner (deflector) that controls the position of the charged particles on the sample is provided in conjunction with the operation of the astigmatism corrector, and the set value (astigmatism corrector) of the astigmatism corrector is changed. The field of view is corrected so that the observed image does not move when the astigmatism is adjusted by canceling the movement of the image with respect to. At this time, a signal proportional to the set value of the astigmatism corrector is input to the aligner for correcting the visual field shift, and this proportional coefficient must be determined so that the image movement is canceled when the astigmatism is adjusted. I have to.
In order to make this adjustment, the setting value (current or the like) of the astigmatism corrector is periodically changed to find the proportional coefficient that minimizes the image movement at this time.

[0004]

In order to manually adjust the optical axis as described above, a technique backed by experience is required, and the adjustment accuracy may vary depending on the operator or the adjustment may take time. is there. Also, in the above-mentioned adjustment by automation, it is necessary to store the adjustment parameter that changes depending on the optical condition for each optical condition, and when observing by changing the optical condition, the registration work is required each time. Further, even if they are used under the same optical conditions, there is a problem that it becomes difficult to make adjustments based on the registered parameters due to the change over time of the optical axis. Further, the operator may not be aware that the axis is displaced and may perform observation or the like based on the deteriorated sample image.

The object of the present invention is to enable easy adjustment of the optical axis even when the state of the charged particle beam changes due to changes in the optical conditions or the change of the optical axis with time, and it is possible to adjust the optical axis. It is to provide a charged particle beam device suitable for realizing automation.

[0006]

In order to achieve the above object, a charged particle source, an optical element for adjusting a charged particle beam emitted from the charged particle source, and an alignment for adjusting the axis of the optical element. In a charged particle beam apparatus including a deflector, an arithmetic means for calculating a deflection amount of the alignment deflector is provided, and the arithmetic means stores a plurality of arithmetic methods for calculating the deflection amount. There is provided a charged particle beam device comprising a selection means for selecting.

With such a configuration, it becomes possible to automatically perform highly accurate axis adjustment regardless of the optical conditions of the charged particle beam. Note that other configurations of the present invention will be described in detail in the section of the embodiments of the present invention.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a scanning electron microscope which is an example of the present invention. Between the cathode 1 and the first anode 2,
A voltage is applied by the high voltage control power source 20 controlled by the computer 40, and the primary electron beam 4 is extracted from the cathode 1 with a predetermined emission current. A high voltage control power source 20 controlled by a computer 40 is provided between the cathode 1 and the second anode 3.
Is applied with an acceleration voltage, the primary electron beam 4 emitted from the cathode 1 is accelerated, and advances to the lens system in the subsequent stage. The primary electron beam 4 is converged by the converging lens 5 controlled by the lens control power source 21, and after the unnecessary area of the primary electron beam is removed by the diaphragm plate 8, the converging lens 6, which is controlled by the lens control power source 22, Then, the objective lens 7 controlled by the objective lens control power supply 23 converges it on the sample 10 as a minute spot. The objective lens 7 can take various forms such as an in-lens system, an out-lens system, and a snorkel system (semi-in-lens system). Further, a retarding method in which a negative voltage is applied to the sample to decelerate the primary electron beam is also possible. Further, each lens may be an electrostatic lens including a plurality of electrodes.

The primary electron beam 4 is supplied to the sample 10 by the scanning coil 9.
The top is scanned two-dimensionally. Sample 1 by irradiation of primary electron beam
A secondary signal 12 such as a secondary electron generated from 0 travels to the upper part of the objective lens 7 and is then separated from the primary electron by a secondary signal separation orthogonal electromagnetic field (EXB) generator 11 to be a secondary signal. It is detected by the detector 13. The signal detected by the secondary signal detector 13 is amplified by the signal amplifier 14, then transferred to the image memory 25 and displayed on the image display device 26 as a sample image.

1 near the scanning coil 9 or at the same position
A stepped deflection coil 51 (an aligner for an objective lens) is arranged and operates as an aligner for the objective lens. Further, between the objective lens and the diaphragm plate, an 8-pole astigmatism correction coil 5 for correcting astigmatism in the X and Y directions.
2 (astigmatism corrector) is arranged. An aligner 53 that corrects the axial deviation of the astigmatism correction coil is arranged near or at the same position as the astigmatism correction coil.

In addition to the sample image, the image display device 26 displays various operation buttons for setting the electron optical system and scanning conditions, as well as buttons for confirming the axis conditions and starting automatic axis alignment. Can be made.

If focus adjustment is performed in a state where the primary electron beam has passed a position deviated from the center of the objective lens (a state in which the axis is deviated), movement of the visual field occurs due to the focus adjustment. When the operator notices the axis shift, he / she can instruct the start of the axis alignment process by an operation such as clicking the process start button displayed on the display device with a mouse. Upon receiving the axis alignment command from the operator, the computer 40 starts processing according to the flow described in the following embodiments.

In the description of FIG. 1, the control processor unit is described as being integrated with the scanning electron microscope or equivalent thereto, but of course, the present invention is not limited to this, and the control processor provided separately from the scanning electron microscope body. Then, the processing described below may be performed. In that case, the detection signal detected by the secondary signal detector 13 is transmitted to the control processor, and the transmission medium for transmitting the signal from the control processor to the lens, the deflector, etc. of the scanning electron microscope, and the transmission medium. An input / output terminal for inputting / outputting a transmitted signal is required. Alternatively, a program for performing the process described below may be registered in a storage medium, and the control processor that has an image memory and supplies necessary signals to the scanning electron microscope may execute the program.

The sample 10 is set on the stage 15.
The stage 15 is controlled by the control signal from the computer 40.
Can move to any position on the sample or on the stage. In addition, a dedicated pattern 16 for performing beam adjustment can be arranged on the stage.

The conditions for automatic operation can be set in advance by the image display device 26 and the input device (mouse, keyboard, etc.) 42. Storage device 41
Is saved as a recipe file in. The recipe file also contains conditions for performing automatic axis adjustment.

(Embodiment 1) Regarding the processing flow of FIG.
The details will be described below.

First step: The present condition of the objective lens 7 or a condition determined based on the present condition (for example, a condition where the focus is slightly deviated from the present focus condition) is set in the objective lens 7 as condition 1. . Next, the present condition of the aligner 51 or a predetermined condition is set as the condition 1 of the aligner 51.
An image 1 is acquired under the objective lens condition 1 and the aligner condition 1.

Second step: With the condition of the aligner 51 unchanged, only the condition of the objective lens is set to the second focus condition in which the focus is deviated from the objective lens condition 1 by a predetermined value. To get.

Third step, fourth step: The condition of the aligner 51 is shifted from the condition 1 by a predetermined value, and the condition 2 is set to the aligner 51. Then, the conditions of the objective lens are set to Condition 1 and Condition 2 as in Steps 1 and 2, and the respective images (Image 3, Image 4) are acquired.

Fifth step: An image is acquired again under the same conditions as the image 1, and this is registered as the image 5.

Sixth step: The parallax (image shift) between the image 1 and the image 2 is detected by image processing, and this is registered as the parallax 1. The parallax between images is, for example, image 1 and image 2.
It is possible to obtain the image correlation while shifting the images of 1 to each other on a pixel-by-pixel basis, and detect from the shift amount of the image having the maximum image correlation value. In addition, any image processing capable of detecting parallax can be applied to this embodiment.

Seventh step: The parallax between the image 1 and the image 2 is detected by image processing, and this is registered as the parallax 2.

Eighth step: The parallax between the image 1 and the image 5 is detected by image processing, and this is registered as the parallax 3.
Since the image 1 and the image 5 were acquired under the same conditions, if there is a deviation (parallax 3) between these images, this deviation is created by the drift of the sample or the beam. That is, when the optical condition of the charged particle beam is set to a certain state (first state), the optical condition is set to another state (second state), and then the first state is set again, The sample image is detected in each of the first states, and the drift is calculated based on the shift between the two.

Ninth step: A drift component is detected from the parallax 3 and the drift component is corrected (removed) with respect to the parallax 1 and the parallax 2. For example, if the capture interval between the image 1 and the image 5 is t seconds, the drift (d) per unit time (second) is represented by d = (parallax 3) / t. On the other hand, if the capturing intervals of the images 1 and 2 and the images 3 and 4 are T12 and T34, the parallax 1 and the parallax 2 are d × T12 and
Therefore, since the drift component of d × T34 is included, by subtracting the drift component from the parallax 1 and the parallax 2, it is possible to calculate the accurate parallax due to the axis shift.

10th and 11th steps: The optimum value of the aligner 51 is calculated from the parallax 1 and the parallax 2 that have been drift-corrected and set as the aligner.

Although the processing flow of FIG. 2 is described as a procedure that makes it easy to understand the operation, the order of capturing images does not affect the processing except for the first and last images (for drift correction). In the actual processing, in order to speed up the processing, for example, the objective lens condition 7 is set to condition 1, images 1 and 3 are continuously captured, and then the objective lens condition 7 is set to condition 2. , Image 2 and image 4 can be continuously captured. Since the objective lens of an electron microscope is usually composed of a magnetic field lens and has a large inductance, a method of continuously controlling an aligner having a small inductance and capable of high speed control is practically effective.

The principle of correcting (correcting) the axial deviation with respect to the objective lens in the processing flow of FIG. 2 will be described with reference to FIG. Position of the aligner 51 when the axis is displaced
The beam off-axis amount at (deflection surface) is WAL (complex variable: XAL
+ J.YAL, j: imaginary unit), and the inclination of the beam with respect to the optical axis at this position is WAL '(complex variable), the orbit calculation based on the electron optical theory (paraxial theory) is possible.
In the case of a magnetic field type objective lens, the lens current value is changed from I1 to I2.
The image shift amount (parallax) that occurs when ΔI (= I1-I2) is changed to ΔWi (complex variable: ΔXi + j · Δ)
Yi), ΔWi can be expressed as follows by the trajectory calculation.

[0029]

[Expression 1] ΔWi = K · ΔI · (WAL · A + WAL ′ · B) (1) Here, K, A, and B are the axial deviation state at the time of measurement and the operating condition of the objective lens (acceleration voltage and objective). The focal length of the lens,
Alternatively, it is a parameter (complex number) determined by the object point position of the objective lens). The state in which the axis is offset with respect to the objective lens means that ΔWi has a value other than 0 in Expression (1). Therefore, conventionally, the current of the objective lens is periodically changed by ΔI, and the image shift ΔWi at this time is changed.
Was recognized by the operator and the aligner conditions were adjusted so as to eliminate the image shift. That is, the optimum value of the aligner in which the axis deviation is corrected refers to the condition that the right side of the equation (1) is 0 regardless of ΔI. If you write this condition out,

[0030]

(2) (WAL · A + WAL ′ · B) = 0 (2), and the operating condition of the aligner that satisfies this condition is the optimum value. If there is an axis deviation, the incident beam is also tilted on the aligner deflection surface, so let this be WAL0 'and the deflection angle (control value) by the aligner be WAL1'.

[0031]

## EQU3 ## WAL '= WAL0' + WAL1 '(3) Therefore, the purpose of the axis adjusting function is to obtain the aligner condition WAL1 ′ (optimum value of the aligner) that satisfies the expression (2). When the aligner is composed of electromagnetic coils, the deflection angle WAL1 'is proportional to the coil current of the aligner. Rewriting equation (1) from the above relationship,

[0032]

## EQU00004 ## .DELTA.Wi = .DELTA.I. (A1 + WAL1'.B1) (4) is obtained. Here, A1 and B1 are the following items.

[0033]

[Equation 5]       A1 = K ・ (WAL ・ A + WAL0 ′ ・ B) (5)

[0034]

[Equation 6]       B1 = K ・ B (6) From the formula (4), the optimum value WAL1 ′ of the aligner is

[0035]

Since it is given by WAL1 '=-A1 / B1 (7), the optimum value of the aligner can be calculated by obtaining A1 and B1. In Expression (4), ΔI is the amount of change in the current of the objective lens, and thus can be determined in advance as a known value. Therefore, when the aligner is set to any two predetermined conditions and the parallax ΔWi with respect to ΔI is detected by image processing in each of them, an equation for obtaining the unknowns A1 and B1 can be obtained from the equation (4). Since A1 and B1 can be solved from this equation, the optimum condition of the aligner can be determined from the equation (7).

That is, under the condition that the parallax ΔWi obtained when the aligner is set to any two predetermined conditions becomes small (ideally, it becomes zero), n-th order equations of unknown quantities such as A and B are obtained. By solving, it is possible to derive a condition that does not depend on the operating condition of the electron optical system. The aligner condition (exciting condition of the aligner) can be derived based on this condition. The aligner 51
Has an arrangement or structure capable of two-dimensionally controlling the beam passage position on at least the main surface of the objective lens. This is because if the deflection fulcrum of the beam due to the aligner exists near the main surface of the objective lens, the state of axis deviation with respect to the objective lens cannot be controlled. That is, in the case of the alignment deflector (aligner) using the electromagnetic coil as in the embodiment of the present invention, it becomes possible to detect the exciting current (deflection signal) to the coil which changes depending on the optical condition.
For example, it is possible to detect the exciting current that changes depending on the change in the excitation condition of the objective lens and the magnitude of the retarding voltage applied to the sample, based on the optical condition at the time of observation. It is not necessary to register it, and even if the beam condition changes due to a change over time, it is possible to detect an appropriate exciting current to the alignment coil in the changed state.

As described above, according to the embodiment of the present invention, it is possible to cope with the changing state of the axis deviation and the operating conditions of the optical element of the charged particle optical system (for example, beam energy, focal length, optical magnification, etc.). It becomes possible to easily realize automation of axis adjustment.

The magnitude of the axis deviation can be quantified by the magnitude of the parallax ΔWi with respect to ΔI. Therefore, for example, when an operation involving a possibility of axis misalignment occurs, such as sample replacement or electron optical system condition change, ΔI
By executing the processing for detecting the parallax ΔWi due to, the axis deviation can be detected in advance. Furthermore, when ΔWi exceeds a predetermined value, a message can be displayed to inform the operator that axis adjustment is required. Figure 5
An example of the message screen when the axis deviation is detected is shown in FIG. According to this message, the operator can cause the input unit to execute the axis adjusting process if necessary. The input means is, for example, a message screen (for example,
Various forms can be taken, such as clicking the icon displayed in FIG. 5) or another dedicated icon displayed on the monitor with a mouse, or designating a processing command from the menu screen.

(Embodiment 2) On the other hand, the astigmatism corrector 52 can also be automatically adjusted in this embodiment. In the astigmatism corrector, the action of converging the beam and the action of diverging the beam occur in different directions in the plane orthogonal to the optical axis. Therefore, if the beam does not pass through the center of the astigmatism correction field, it will be deflected in the direction corresponding to the deviation from the center of the astigmatism correction field. At this time, since the deflection action also changes in association with the correction of astigmatism, the image moves in conjunction with the adjustment operation of astigmatism, making the adjustment operation difficult. In order to correct this, conventionally, a signal interlocked with the signals (Xstg, Ystg) of the astigmatism corrector 52 is input to another aligner 53, and the astigmatism corrector is generated by the movement of the image generated by the aligner 53. The movement of the image due to is canceled. At this time, if the signal (complex variable) input to the aligner 53 is Ws1, Ws1 is expressed by the following equation.

[0040]

## EQU8 ## Ws1 = Ksx.Xstg + Ksy.Ystg (8) Here, Ksx and Ksy are coefficients represented by complex variables. Now, assuming that the signals (Xstg, Ystg) of the astigmatism corrector are changed by ΔXstg and ΔYstg, respectively, the movement (parallax) of the observed image corresponding to each change.
ΔWix and ΔWy are as follows, respectively.

[0041]

[Equation 9]       ΔWix = ΔXstg · (Asx + Bx · Ksx) (9)

[0042]

[Expression 10] ΔWiy = ΔYstg · (Asy + By · Ksy) (10) Here, Asx and Asy are complex variables whose values are determined corresponding to the axis deviation of the beam with respect to the astigmatism corrector. K
sx and Ksy represent axis adjustment parameters (complex variables) controlled by the device. Bx and By are complex variables determined by the position of the aligner, the deflection sensitivity, the conditions of the electron optical system, and the like. Conventionally, the astigmatism correctors are respectively ΔXstg, Δ
The Ystg modulation signal is added, and the image movement (Δ
The operator recognizes (Wix, ΔWy), and the parameters Ksx, Ksy are manually adjusted so as to eliminate this.

This is the axis adjustment operation for the astigmatism corrector. That is, the operation of aligning the axis with the astigmatism corrector is performed by using ΔXst in Equations (9) and (10).
This corresponds to obtaining coefficients Ksx and Ksy at which ΔWix and ΔWyy become 0 regardless of g and ΔYstg. Note that Δ
Although it is ideal that Wix and ΔWy are zero, the present invention is not limited to this, and the coefficient may be obtained under the condition that ΔW is reduced so as to be close to zero. Formula (9)
The form of the equation (10) and the equation (10) are exactly the same as the equation (4) shown above. If the current value change (ΔI) of the objective lens is replaced with the signal change (ΔXstg, ΔYstg) of the astigmatism corrector, The optimum control parameters (Ksx, Ksy) for the aligner 53 can be obtained by the detection and the arithmetic processing thereof. The processing flow for this is shown in FIG. Since the aligner that corrects the field shift by the astigmatism corrector is for correcting the position of the beam on the sample, it must be arranged at a position where the position on the sample can be controlled.

The magnitude of the axis deviation with respect to the astigmatism corrector can be quantified by the image deviation (parallax) when the signals of the astigmatism corrector are changed by ΔXstg and ΔYstg. Therefore, in this embodiment, as in the case of the axis deviation with respect to the objective lens described above, an operation that may change the state of the optical axis (change of accelerating voltage, sample exchange, change of focus position, etc.) is performed. In this case, parallax detection can be performed and the operator can be notified by displaying the state of axis deviation. According to this display, the operator can instruct to execute the axial alignment processing of the astigmatism corrector, if necessary, by the input means displayed on the screen. Input means, for example, by clicking the dedicated icon displayed on the monitor with the mouse, or specify the process from the menu screen,
It can take various forms.

In the embodiment of the present invention, when the operator erroneously instructs the axis adjustment processing in an improper image state (a state in which the focus is significantly deviated or an image in which structural information is hardly included), the processing is performed. Can be prevented from malfunctioning. This function will be described with reference to the processing flow of FIG. When it is instructed to start the axis misalignment detection process or the axis adjustment process, the CPU 40 first captures the current image and executes a quantification (image quality quantification) process of the captured image. The processing by the quantification means quantifies whether or not the image has structural information necessary for parallax detection. The output of this processing is, for example, the Fourier transform of the image, and the quantitative value Fi calculated from the result by the following equation.
Can be used.

[0046]

Fi = ΣΣ [F (fx, fy) · fx ⁿ · fy ⁿ ] (11) where F (fx, fy) represents the two-dimensional Fourier transform (FFT) of the image, and fx and fy are Represents spatial frequency. By using a real number or an integer of 1 or more as the index n, it is possible to appropriately quantify the image quality. That is, if there is no structural information in the image, F (f
Since x, fy) is a very small value, it is possible to judge from the calculation result of Expression (11) whether or not there is structural information suitable for image quality. When the quantitative value Fi is less than or equal to a predetermined value that is determined in advance, or less than the predetermined value, an alarm may be issued by determining that the quantitative value Fi is not suitable for alignment signal calculation. This alarm may be displayed or sounded as shown in FIG.

(Embodiment 3) FIG. 7 is a diagram for explaining a third embodiment of the present invention. A setting screen for setting an environment for automatic axis deviation correction displayed on the image display device is shown in FIG. FIG. The operator of the scanning electron microscope sets the environment of automatic axis adjustment from this screen. In the case of the present embodiment, an example of setting with the pointing device 60 on the setting screen will be described. First, the operator determines whether or not to automatically execute the aperture alignment, and selects either "correction based on parallax detection", "predetermined value correction" or "no correction". The “correction based on parallax detection” is a mode in which the axis deviation is corrected in the steps described in the first embodiment. If this mode is selected, stable axis correction accuracy can be obtained for a long time regardless of changes with time of the primary electron beam.
The “preset value correction” is performed by registering in advance a memory (not shown) with the axis deviation that occurs for each excitation condition of the objective lens and each distance (a plurality of optical conditions such as working distance) between the sample and the objective lens, and the predetermined optical In this mode, when the condition is set, the axis adjustment is performed under the registered axis adjustment condition. This mode may be selected, for example, when there is no change in the axis deviation over time, or when substantially the same axis deviation is recognized even if the optical conditions are changed. In this setting, since the correction is performed based on the default value, it is possible to improve the processing time without detecting the axis adjustment condition and the calculation time. "No" is a mode in which axis adjustment is not performed, and it is desirable to select in an environment where axis deviation does not occur.

As described above, by making it possible to select a plurality of correction modes on the environment setting screen, it becomes possible to select an appropriate correction condition based on the usage conditions of the scanning electron microscope, the environment and the like. .

Next, the operator selects automatic axis adjustment timing. For example, if there is a high frequency of axis misalignment, set "for each analysis point" in consideration of the accuracy of the axis adjustment and perform axis misalignment correction at each measurement point so that it seems that axis misalignment does not occur much. If available, "per wafer" considering throughput
Is selected, and the axis deviation is corrected every time the wafer to be measured by the scanning electron microscope is exchanged. By providing such an option, it becomes possible to select an appropriate axis deviation correction timing based on the usage conditions and environment of the scanning electron microscope. If "when the value exceeds the predetermined value" is selected, the parallax ΔWi with respect to the objective lens current change amount ΔI is detected for each analysis point or each wafer, and when the value ΔWi exceeds the predetermined value, "correction based on the parallax detection". Is done. In addition, if "User setting" is selected, the axis adjustment is performed at the axis adjustment timing that is separately registered in advance.

Next, the operator selects whether to register the correction amount graph or not. The correction amount graph mentioned here is displayed on the image display device in a form as shown in FIG.
In the technique shown in the first embodiment, the coil current to the astigmatism corrector aligner 53 is finally calculated. The difference between the coil current and the coil current before correction is how much the beam deviates from the optical axis. It indicates whether or not it has occurred, and by plotting this degree and making a graph, it is possible to determine the transition of the degree of axis deviation. If the shift of the axis shift shows a nearly constant value, it is judged that the state of the axis shift thereafter is also the same, and by switching to the above “preset value correction”, “parallax detection” is performed. It is possible to eliminate the detection time and the calculation time of the axis adjustment condition required for the "correction based on" and to improve the throughput. By displaying such a graph, it is possible to entrust the operator with a judgment for performing an appropriate automatic axial adjustment, and it is possible to set an appropriate axial adjustment condition.

The graph shown in FIG. 8 (b) is an example in which the measurement result of the semiconductor pattern width is displayed by being superimposed on the correction amount graph of FIG. 8 (a). The length measurement of the semiconductor pattern width is formed based on the detection amount of secondary electrons or backscattered electrons obtained by one-dimensionally or two-dimensionally scanning an electron beam on a semiconductor device having a pattern to be measured. This is done by measuring the width of the line profile. The length measurement result of the target pattern thus obtained and the error of the pattern dimension based on the design information are superimposed and plotted on the correction amount graph shown in FIG.

In FIG. 8 (b), the part marked a is
Since the parallax ΔWi exceeds a certain defined range or there is no structural information necessary for parallax detection (when the quantitative value Fi described in the second embodiment is less than or less than a certain value), “for parallax detection This is the point where the length measurement was performed under the condition that "based correction" was not performed. It is desirable to display this portion by distinguishing it from other portions such as changing the color so that it can be distinguished from the case where the correction amount is zero. In the following description, when the parallax ΔWi exceeds the predetermined range, the case where the length measurement is executed without performing the “correction based on the parallax detection” will be described, but the present invention is not limited to this, and the axis adjustment can be performed by the operator as described above. It is also possible to stop the automatic length measurement by issuing an alarm for prompting such as. If the length measurement is continued even though the “correction based on parallax detection” is not performed, the obtained length measurement value may be incorrect. In such a case, in order to visually confirm whether or not the length measurement was correctly performed later, along with the length measurement value, the sample image, line profile, and
Alternatively, at least one of the optical conditions of the electron microscope may be stored. The operator can judge the reliability of the length measurement by comparing the obtained length measurement result with the above information.

Next, the operator selects what kind of processing is to be performed when the parallax ΔWi exceeds a predetermined range or when the set value Fi is below or below a certain value. When "Stop measuring" is selected, the automatic and continuous measurement is stopped, and the electron beam is blanked by the blanking mechanism (not shown) so that the sample is not irradiated and the standby state is set. At this time, on the image display screen,
You may display the message as shown in FIG. Of these, mere “continuation” is a mode in which the length measurement is performed as it is without performing “correction based on parallax detection”. The “continuation of registration of sample image” is a mode in which a sample image obtained without performing “correction based on parallax detection” as described above is registered together with the length measurement result. “Switch to default value correction” is effective when “correction based on parallax detection” cannot be performed and the situation of axis misalignment is known to some extent. In this mode, axis deviation is performed based on the correction amount registered in advance. Alternatively, the length measurement may not be performed, and the measurement may be skipped to the next vertex. Of course, the environment setting screen described so far can be applied for stigma alignment.

In order to determine whether or not the automatic axial adjustment described in this embodiment is properly performed, at least four sample images used for "correction based on parallax detection" are used. It may be displayed on the image display screen in real time. In the above description, the axial adjustment is performed for the objective lens and the astigmatism corrector. However, the present invention is not limited to this, and general charged particle beam optical elements that require optical axis adjustment using an alignment deflector. Is applicable to. Furthermore, the present invention can be applied not only to the electron microscope but also to all charged particle beam devices that converge a charged particle beam using a focused ion beam or an axially symmetric lens system. An electrostatic deflector may be used as the aligner deflector.

(Embodiment 4) Next, in particular, a scanning electron microscope for measuring the width of a pattern on a semiconductor wafer and the dimensions of contact holes, the presence of defects on the semiconductor wafer are inspected, and the detected defects are reviewed. In a device such as a scanning electron microscope in which a large number of samples are continuously introduced and automation is especially desired, the axis adjustment for the optical element (objective lens or astigmatism corrector) for adjusting the electron beam is performed. A preferred embodiment will be described.

9 and 10 are flowcharts for explaining this embodiment, which are executed in accordance with a program stored in the storage device 40 in advance or an instruction input from the input device 42. The difference between the flowchart shown in FIG. 9 and the flowcharts shown in FIGS. 2 and 4 is that the axis adjustment method is constant in the flowcharts shown in FIGS. 2 and 4, whereas the flowchart shown in FIG. There is a point that the method of axis adjustment changes.

In step 2001, an initial value (for example, current condition 1) A0 of the adjustment aligner (objective lens aligner 51 or astigmatism correction aligner 53) is acquired and stored in the computer 40. In step 2002, the image movement (parallax referred to in Examples 1 to 3) W1 is calculated. The image movement amount is calculated in step 300 described later.
1 to 3006. In step 2003, it is determined whether or not η is recalculated according to a flag given in advance. Here, η is an unknown number that should be obtained in this embodiment as described later. When recalculating, steps 2004 to S2006 are executed. If not, the image movement W2 is set to 0, a value given in advance is set to η, and then step 2011 is executed. In S2004, a condition (condition 2) in which the shift amount ΔA1 is shifted from the initial value A0 of the aligner stored in the computer 40 is set in the aligner. In S2005, steps 3001 to 3001
The image movement W2 is calculated according to the processing flow of 3006.

Next, at step 2006, η is calculated from the equation (12) using the image movement W1 and the image movement W2 stored in the computer 40.

[0059]

Η = −1 / (W2-W1) (12) In step 2007, ε is set according to a flag given in advance.
Determines whether to recalculate. Here, ε is a constant peculiar to the apparatus, which should be obtained in this embodiment as described later. When recalculating, steps 2008-2
010 is executed. If not, set the image movement W3 = 0,
After setting the value given in advance to ε, step 2011
To execute. In step 2008, the shift amount ΔA with respect to the aligner initial value A0 stored in the computer 40.
The condition in which 2 is shifted (condition 3 different from condition 1 and condition 2 described above) is set as the aligner. In step 2009,
The image movement W3 is calculated by the processing flow of steps 3001 to 3006.

In step 2010, the computer 40
Ε is calculated from the equation (13) using the image movement W1, the image movement W2, and the image movement W3 stored in the table.

[0061]

[Equation 13] ε = (W3−W2) / (W2−W1) (13) Then, in step 2011, the alignment correction value X, based on the image movements W1, η, ε, and | ΔA1 | Y is calculated, and alignment correction values X and Y are set in the aligner.

[0062]

X + jε · Y = | ΔA1 | · η · W1 (14) In step 2012, the absolute value (X · X + Y · Y) of the alignment correction value (that is, the actual axis deviation amount) is a predetermined threshold value. If it is equal to or greater than the above, a retry process (steps 2001 to 2012) is performed. The retry process supplements the deviation calibration accuracy when an image is captured and a deviation is detected in a state where the initial adjustment is largely out of alignment. By repeating the correction a plurality of times in this way, the deviation can be corrected with higher accuracy.

Next, the image movement calculation step is shown in FIG.
It will be described using 0. In step 3001, an initial value (for example, current condition) C0 of the adjustment target coil (objective lens 7 or astigmatism corrector 52) is acquired and stored in the computer 40. In step 3002, a condition (as condition 1) in which a predetermined value ΔC is deviated from the initial value C0 of the adjustment target coil is set to the adjustment target coil. Step 30
In 03, the image 1 is acquired under the condition 1 and stored in the image memory 25. In step 3004, the adjustment target coil is set as a condition (condition 2) in which −ΔC which is predetermined with respect to the initial value C0 of the adjustment target coil is shifted.

In step 3006, the image movement W is calculated by the image processing device 27 from the image 1 and the image 2 and stored in the computer 40. The image movement W is a vector of (x, y), and is a shift amount between the image 1 and the image 2. The displacement amount is calculated by using the partial image of the image 1 as a template and the position most similar to the image 2 by the formula (15).

[0065]

[Equation 15]

R (X, Y) is the correlation value at (X, Y), and P _ij is the point (X + _i , corresponding to image 2 of image 1 ₎ .
Y + _j ), and M _ij is a point (X + _{i + 1} , Y
+ _{J + 1} ), and N is the number of pixels of the pattern mask. The shift amount to be obtained is calculated from the partial image position of the image 1 by (X,
Y) is subtracted. This method has a high degree of freedom because it does not select a pattern.

Further, as another method for calculating the image movement, the following one can be considered. If the image for calculating the image movement contains a specific shape (for example, if a hole pattern is included in the image), the position of the pattern in image 1 and image 2 is detected by the following method. The amount of deviation can be detected.

First, the image 1 is differentiated by the differential filter, the threshold value is set so that the edge remains, and the binary screen is created. A segment process is applied to this binary screen to extract only the edges forming the pattern. The center of gravity (x1, y1) of the pattern is calculated from the extracted edge information. The same process is applied to the image 2, and the pattern center of gravity (x
2, y2) is calculated. The required shift amount is W (x2-
x1, y2-y1). This method has an advantage that even if a pattern whose original shape is a circle is detected as an ellipse by changing the electron optical conditions, the center of gravity position hardly changes and the pattern is strong against deformation.

The processing flow described here is the same for the aligner 51 for the objective lens and the aligner 53 for the astigmatism corrector (X direction, Y direction) only with different control values. Further, ε is a constant peculiar to the apparatus regarding the sensitivity difference and the orthogonal shift arranged in the X and Y directions. Therefore, the value obtained at the time of starting the apparatus or periodically is stored in the storage device 41. The stored value is read by the computer 40 before the execution of this processing flow, and thus the step 200
8 to 2010 can be omitted. Further, when the axis adjustment is performed in a relatively short cycle without changing the electro-optical condition, the previously calculated value of η can be stored in the computer 40 and the value can be used as η.

As described above, in the present embodiment, 6 images obtained by changing the optical conditions are used to obtain ε
And a mode for recalculating a predetermined variable such as η (hereinafter referred to as a 3-point measurement mode), which is obtained by changing the optical conditions.
A mode in which only η is recalculated based on the number of images (2 below)
It is characterized in that a point measurement mode) and a mode in which ε and η are not recalculated (hereinafter referred to as a one-point measurement mode) are used properly according to the situation. High axis adjustment accuracy can be obtained in the 3-point measurement mode, while 2 in the 1-point measurement mode.
Only one image is enough, and the processing speed can be increased. Since each mode has unique effects in this way, it is desirable to use each mode as follows, for example.

The three-point measurement mode is performed, for example, when the semiconductor inspection device is started up, and ε is calculated at that time.
The two-point measurement mode is executed once a day or when the recipe of the semiconductor manufacturing apparatus is largely changed, and ε is read from the storage device 41 and used. The 1-point measurement mode is executed for each measurement point of the semiconductor wafer to be inspected, and ε
Is read from the storage device 41 and η is read from the computer 40 and executed. Needless to say, the example described here is merely an example, and can be changed according to the type of the apparatus, the measurement conditions, and the like.

Since the shift amount ΔA uses the sample image to detect the image movement, it is necessary to satisfy the following two conditions. (1) The shift amount must be large enough to recognize that the sample pattern has moved.
(2) It is necessary to reduce the shift amount in advance so that the sample pattern does not come off the screen. The conditions (1) and (2) can be determined if the geometrical position of the sample pattern is known. That is, the shift amount ΔA is determined from the geometrical arrangement of the sample pattern and the observation magnification. This ΔA may be determined, for example, by providing an automatic sequence that is set small at high magnification and large at low magnification.
You may make it input automatically from the input device 42.

According to the embodiment of the present invention, in the apparatus for adjusting the axis of the charged particle optical system based on the obtained sample image,
By providing the calculating means and the selecting means of a plurality of axis adjusting methods (a plurality of calculating methods) as described above, it is possible to achieve both high axis adjusting accuracy and high processing speed. Such a technical effect is that the semiconductor wafers having a plurality of measurement points are continuously introduced, and the automatic operation is continuously performed, so that the optical conditions may change with time. It is particularly effective for a semiconductor inspection device in which conditions change, and an appropriate axis adjustment method can be assigned each time.

The parameter η used in this embodiment represents how the image movement amount (including the direction) changes when the alignment coil is operated, and is a parameter including the alignment deflection sensitivity. However, it depends not only on the deflection sensitivity of simple alignment but also on the operating conditions of the electron optical system.

In this embodiment, the basic equation (1) described in the previous embodiment is converted as follows and replaced with a parameter η. The inclination of the electron beam trajectory in the alignment coil section described in the previous embodiment includes both the deviation due to the axis shift (WAL0 ') and the deflection due to the current setting value of the alignment coil (WAL1'). further,
The inclination of the beam with respect to the amount of change (setting change amount) relative to the current setting value of the alignment coil is (WAL
2 ')

[0076]

[Equation 16]       WAL '= WAL0' + WAL1 '+ WAL2' (16) Becomes

The parameter required for control in equation (16) is W
Since it is AL2 ', all other terms are constants and equation (1) is used.
Is expressed as

[0078]

[Expression 17] ΔW = ΔI · K · (A1 + B1 · WAL2 ′) (17) Here, the image movement amount given by ΔI · K · A1 corresponds to the image movement amount generated under the condition of the current alignment set value.

On the other hand, the relationship between the DAC value (X, Y) of the alignment coil and WAL2 'can be written as follows.

[0080]

WAL2 ′ = k · (X + jε · Y) (18) Here, k is a coefficient representing the sensitivity of the alignment coil X, and ε is the complex relative sensitivity of Y to X (the absolute value of ε is the sensitivity ratio). , Arg (ε) are orthogonality deviations. Expression (1
When 8) is substituted into the equation (17) and meaningless coefficients are collectively expressed as one, the image movement amount ΔW when the objective lens current is changed is

[0081]

[Formula 19]       ΔW = A2 + B2 · (X + jεY) (19) Can be written.

Since the condition of the current center axis is ΔW = 0, the alignment value satisfying this condition is

[0083]

[Equation 20]

It is calculated by Therefore, from the image movement amount, A2
And B2 are derived, the alignment control values (X, Y) with which the current center axis is obtained can be calculated from the equation (17). To calculate A1 and B2, the image movement amount W1 and X = X1 ≠ when X = Y = 0 in the equation (17).
The image movement amount W2 when 0 and Y = 0 is detected. That is,

[0085]

[Equation 21]       W1 = A2 (21)

[0086]

[Equation 22]       W2 = A2 + B2X1 (22) From this, equation (20) becomes

[0087]

[Equation 23]

It becomes

In the present embodiment, -1 / (W2 in equation (23)
The term of −W1) is defined as η. If η is rewritten,

[0090]

[Equation 24]

It becomes

(Embodiment 5) FIG. 11 is a diagram for explaining an embodiment of fully automatic axis adjustment. The fully automatic axis adjustment in the present embodiment means the stage 1 at a predetermined timing.
5 is driven, the adjustment pattern 16 is positioned immediately below the electron beam, and the magnification and imaging are set from the pattern information.
For example, a control including a series of operations of adjusting the X direction of the astigmatism correction aligner 53, and then adjusting the Y direction of the astigmatism correction aligner 53, and adjusting the objective lens aligner 51 is automatically performed. That is. The order of adjusting the astigmatism correction aligner 53 and the objective lens aligner 51 is determined by the arrangement of the lenses in the electron optical system. In the case of the electron optical system as shown in FIG. 1, if the axis adjustment is performed by the astigmatism correction aligner 53 after the adjustment by the objective lens aligner 51, the optical axis with respect to the objective lens may be displaced again. Therefore, it is desirable to adjust in order from the optical element located closer to the cathode. On the other hand, in the case of an electron optical system in which the objective lens and the astigmatism corrector are arranged in this order from the cathode, it is desirable to adjust the objective lens aligner and the astigmatism corrector aligner in this order.

In the description of this embodiment, an adjustment pattern different from that of the sample is provided, but the invention is not limited to this, and axis adjustment is performed using a specific pattern on the sample 10 (semiconductor wafer or the like) to be observed. You may go.

FIG. 11 shows details of the processing flow of fully automatic axis adjustment.
A description will be given using the automatic axis adjustment condition setting screen 500 of FIG. FIG. 12 is displayed on the image display device 26 as a screen for setting one condition of the recipe file in which the condition of the automatic operation is registered. The user sets automatic axis adjustment conditions on this screen and starts automatic operation. The processing flow of fully automatic axial adjustment when executing automatic operation will be described below.

In step 4001 of FIG. 11, the pattern information registered in advance in the storage device 41 is read and the shift amount is calculated from the magnification. Further, ε and η are initialized as needed based on the measurement mode described in the previous embodiment. The pattern information used for the axis adjustment determines whether the adjustment pattern 16 on the stage or the pattern on the wafer is used by selecting the adjustment pattern flag 502 or the wafer pattern flag 503. When the wafer pattern flag 503 is selected, the stage coordinates of the pattern, the sample image acquisition magnification, and the number of frames for acquiring the sample image are also displayed in the numerical input window 5 respectively.
Input from 04, 505, 506. When the adjustment pattern flag 502 is selected, the stage coordinates, the magnification, and the number of frames stored in the storage device 41 in advance are set in the respective numerical value input windows. Note that step 400
The number of frames set in 1 is the total number of times of scanning images for forming a pattern image. In this embodiment, one pattern image is obtained by integrating 16 sample images.

In step 4002, the stage coordinates 504 are extracted from the pattern information and moved to the pattern position. When the adjustment pattern flag 502 on the stage is selected, the stage is moved so that the axis adjustment pattern 16 is positioned immediately below the electron beam. The current value supplied from the scanning coil control power supply 24 to the scanning coil 9 is set according to the magnification input from the numerical value input window 505 during this movement.

In step 4003, it is determined whether the automatic focus adjustment execution flag 501 is ON or OFF, and if it is ON, automatic focus adjustment is executed. In step S4004, images of the number of frames input from the numerical value input window 506 are integrated to form a sample image. In step 4005, if an instruction to turn on the astigmatism correction aligner (X direction) adjustment flag 507 is issued, adjustment of the astigmatism correction aligner (X direction) (steps 2001 to 2012, steps 3001 to 3001)
3006) is executed. In step 4006, the astigmatism correction aligner (Y direction) adjustment flag (508) is turned ON.
, The astigmatism correction aligner (Y direction)
Adjustment (steps 2001 to 2012, step 300
1 to 3006) are executed. In this adjustment, if the detection of the amount of deviation has failed and the automatic focus adjustment execution flag 501 is OFF, focus is adjusted and another attempt is made.

In step 4007, if the objective lens aligner adjustment flag 509 is ON, adjustment of the objective lens aligner (steps 2001 to 2012, steps 3001 to 3006) is executed. Step 4008
Then, when the three-point measurement mode flag 511a is selected, ε is stored in the storage device 41, and η is stored in the computer 40. When the two-point measurement mode flag 511b or the one-point measurement mode flag 511c is selected, η is stored in the computer 40.

In this embodiment, each measurement mode is selected by a predetermined flag. However, for example, depending on the situation of the image movement W1 calculated in step 2002,
It may be determined in which mode the axis adjustment is performed (for example, when the image movement W1 is large, calculation based on many images is performed). The mode may be selected not only by moving the image but also by other information obtained by comparing the two images. As described above, not only the operator's instruction but also which measurement mode to use may be automatically selected. That is, the selection means for selecting the calculation method of the present invention is not limited to the one preset by the operator as described in the previous embodiment, but a calculation method for calculating the shift amount based on the image evaluation. It may be changed automatically. Step 400
In No. 9, automatic astigmatism adjustment is performed when the automatic astigmatism adjustment flag 510 is ON.

When executing automatic axis adjustment in automatic operation, all flags (501, 507, 508, 509,
Turn on 510) and execute. When the sample is moved to a predetermined pattern position, the height of the sample may deviate from the focus position adjusted before the movement. If axis adjustment is performed in this misaligned state, the image misalignment will be detected in a pattern in which the image is out of focus and in a blurry image, so the axis adjustment accuracy deteriorates, but autofocusing is performed as in this embodiment. This problem can be solved by detecting the image shift after the error.

Astigmatism correction aligner (X, Y direction)
In addition, it is difficult to adjust which of the three axes of the objective lens aligner is displaced unless the operator is originally skilled. Therefore, in most cases, even if the axes are manually adjusted, almost all the axes are adjusted. According to the embodiment of the present invention, focus adjustment (autofocus), axis adjustment for the astigmatism corrector (axis adjustment by the first alignment deflector), axis adjustment for the objective lens (axis adjustment by the second alignment deflector). ,
Since the optical adjustment is automatically controlled in the most appropriate order of astigmatism correction, the axis adjustment can be performed with high accuracy and high throughput.

As shown in FIG. 12, if the setting items of the recipe are arranged in the adjustment order of the actual optical system, the recipe can be set while imagining the actual adjustment performed in the electron optical system. This has the effect of making settings easier.

If the images used in the respective measurement modes described in the previous embodiment and this embodiment are once stored in real time or in the image memory 25 and then displayed on the image display device 26, the axis adjustment can be performed. It is possible to visually confirm whether or not is properly performed. For example, when the axis is adjusted with the focus clearly deviated, the image display device 26
Since a defocused and blurred image is displayed on the screen, the operator can see the situation and judge the reliability of the axis adjustment process.

(Sixth Embodiment) FIG. 13 is a diagram for explaining a sixth embodiment of the present invention, and is a schematic processing flow of automatic astigmatism adjustment after execution of automatic axis adjustment. The processing is performed in three large steps (first step: steps 6001 to 60).
03, second step: steps 6004 to 6006, third step: steps 6007 to 6009). In the first step, the positive focus position of the objective lens is set. In the second step, the optimum value of the astigmatism corrector (X direction) is set. In the third step, the optimum value of the astigmatism corrector (Y direction) is set.

In step 6001, the initial value R0 of the objective lens control value is determined by the current value R and the predetermined width ΔR. The initial value is obtained by R0 = R-ΔR / 2. In step 6002, an image is captured while increasing the initial value R0 of the objective lens control value by a predetermined width dR. dR is calculated by dR = ΔR / N, and N is an evaluation score. The captured image is transferred to the image processing device 27 and the evaluation value is calculated. Evaluation values are 0 °, 90 °, 45 °
The signal amount (for example, the sum of the differential images) in four directions, ie, the direction 135 ° and the direction 135 °, is obtained.

At step 6003, N in each of the four directions
An average of these four control values for obtaining the maximum control value of the objective lens in each direction from the evaluation value calculated by the point calculation is set to the objective lens as the optimum value. In step 6004, the initial value S0 of the control value of the astigmatism corrector (X direction) is determined by the current value S and a predetermined width ΔS. The initial value is
It is calculated by S0 = S−ΔS / 2. In step 6005, an image is captured while increasing the control value S0 of the astigmatism corrector (X direction) by a predetermined width dS. dS is calculated by dS = ΔS / N, and N is an evaluation score. The captured image is transferred to the image processing device 27 and the evaluation value is calculated. As the evaluation value, the signal amount of the entire image (for example, the sum of differential images) is obtained. The above processing is performed from S0 to S0 + Δ
Execute up to S.

In step 6006, of the evaluation values calculated for N points, the control value with the maximum evaluation value is set in the astigmatism corrector (X direction) as the optimum value. Step 6007
In steps 6009 to 6009, the same processing as steps 6004 to 6006 is performed for the astigmatism corrector (Y direction).

According to this method, the correct focus position can be detected for the image containing the astigmatism in the first step, and the automatic astigmatism can be executed with the image in which the regular focus position is set. Conversely, after the second and third steps, the first
When the step is executed, astigmatism is performed on an image that is not at the regular focus position, and it becomes difficult to obtain an optimum astigmatism correction value.

[0109]

According to the present invention, it is possible to perform highly accurate axis adjustment regardless of the optical conditions of the charged particle beam device.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a scanning electron microscope which is an example of the present invention.

FIG. 2 is a schematic processing flow for correcting an axis deviation with respect to an objective lens.

FIG. 3 is a principle diagram for correcting an axis deviation with respect to an objective lens.

FIG. 4 is a schematic processing flow for correcting an axis deviation for an astigmatism corrector.

FIG. 5 is an example of a message when an axis deviation is detected.

FIG. 6 shows an example of axis deviation detection processing including image quality determination processing.

FIG. 7 is a diagram showing a setting screen for setting an environment for automatic axis deviation correction.

FIG. 8 is a diagram showing a display example of a correction amount graph.

FIG. 9 is a schematic processing flow for correcting an axis deviation.

FIG. 10 is a processing flow for detecting an image shift.

FIG. 11 is a schematic process flow when executing automatic operation.

FIG. 12 is a setting screen for setting an environment for automatic axis deviation correction during execution of automatic operation.

FIG. 13 is a schematic process flow of automatic astigmatism adjustment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cathode, 2 ... 1st anode, 3 ... 2nd anode, 4 ... Primary electron beam, 5 ... 1st converging lens, 6 ... 2nd converging lens, 7 ... Objective lens, 8 ... A diaphragm plate, 9 ... Scanning coil 10 ... sample,
11 ... Quadrature electromagnetic field (EXB) generator for secondary signal separation, 1
2 ... secondary signal, 13 ... secondary signal detector, 14a ... signal amplifier, 15 ... stage, 16 ... axis adjustment pattern, 2
0 ... High-voltage control power supply, 21 ... First converging lens control power supply, 2
2 ... Second convergent lens control power supply, 23 ... Objective lens control power supply, 24 ... Scan coil control power supply, 25 ... Image memory, 2
6 ... Image display device, 27 ... Image processing device, 31 ... Objective lens aligner control power supply, 32 ... Astigmatism corrector control power supply, 33 ... Astigmatism corrector control power supply, 40 ... Computer, 41 ... Storage device, 42 ... Input device, 51 ...
Objective lens aligner 52 ... Astigmatism corrector 53 ... Astigmatism corrector

Continued front page    (72) Inventor ▲ High ▼ Atsushi Ne             882 Ichige, Ichima, Hitachinaka City, Ibaraki Prefecture             Ceremony company Hitachi measuring instruments group (72) Inventor Mitsugu Sato             882 Ichige, Ichima, Hitachinaka City, Ibaraki Prefecture             Ceremony company Hitachi measuring instruments group F-term (reference) 4M106 AA01 BA02 CA38 DB05 DB18                       DB20                 5C030 AA06 AB02                 5C033 FF03 JJ01                 5F056 BA09 BB01 BC08 BC10 CB28                       CB29 CC04 EA06

Claims (8)

[Claims] 1. A charged particle beam apparatus comprising a charged particle source, an optical element for adjusting a charged particle beam emitted from the charged particle source, and an alignment deflector for adjusting the axis of the optical element. The alignment deflector further comprises a calculating means for calculating a deflection amount, the calculating means stores a plurality of arithmetic methods for calculating the deflection amount, and a selecting means for selecting the arithmetic method is provided. Charged particle beam device. 2. The calculation means according to claim 1, wherein the calculation means calculates the deflection amount of the alignment deflector based on the movement amount between a plurality of images obtained when the condition of the optical element is changed. The charged particle beam device according to claim 1. 3. The calculation means according to claim 1, wherein the calculation means calculates a deflection amount of the alignment deflector based on a movement amount between a plurality of images.
The charged particle beam device, wherein the number of images used for the calculation is changed by the selection of the calculation method by the selecting means. 4. The calculation means according to claim 1, wherein the calculation means calculates a predetermined variable from a movement amount between a plurality of images obtained when the condition of the optical element is changed, and based on the predetermined variable. A charged particle beam apparatus for calculating a change amount of the alignment deflector, wherein the number of images to be used for the calculation is changed by selection of a calculation method by the selecting means. 5. A charged particle beam apparatus equipped with a charged particle source, an optical element for adjusting a charged particle beam emitted from the charged particle source, and an alignment deflector for axially adjusting the optical element, A calculation means for calculating the deflection amount of the alignment deflector; and when the deflection amount calculated by the calculation means is greater than or equal to a predetermined value or greater than that value, the processing by the calculation means is performed again. Charged particle beam device. 6. A charged particle beam apparatus comprising a charged particle source, an optical element for adjusting a charged particle beam emitted from the charged particle source, and an alignment deflector for adjusting the axis of the optical element, Based on the means for detecting the center of gravity of the patterns of the two images obtained when the condition of the optical element is changed, the means for detecting the deviation of the centers of gravity of the two patterns, and the deviation of the centers of gravity of the two patterns. And a means for calculating a deflection amount of the alignment deflector. 7. A charged particle source, an astigmatism corrector for performing astigmatism correction on a charged particle beam emitted from the charged particle source, and the astigmatism corrector and a sample irradiated with the charged particle beam. An objective lens disposed between and for focusing the charged particle beam, a first alignment deflector for adjusting an optical axis of the charged particle beam with respect to the astigmatism corrector, and a light beam for the charged particle beam with respect to the objective lens. In a charged particle beam device including a second alignment deflector for adjusting the axis, firstly, the focus adjustment is performed by the objective lens, secondly, axis adjustment is performed by the first alignment deflector, and thirdly. Axis adjustment by the second alignment deflector,
1. A charged particle beam device, further comprising control means for controlling to perform astigmatism correction by the astigmatism corrector. 8. A charged particle source, an optical element for adjusting a charged particle beam emitted from the charged particle source, an alignment deflector for adjusting the axis of the optical element, and an irradiation of the charged particle beam. In a charged particle beam device provided with an image display device that displays an image based on a secondary charged particle beam emitted from a sample, in a movement amount between a plurality of images obtained when the conditions of the optical element are changed. Based on the above, a calculation means for calculating the deflection amount of the alignment deflector is provided, and a plurality of images obtained when the conditions of the optical element are changed are displayed on the image display device in the previous period. Particle beam equipment.