JPH0765760A - Method and device for removing electron beam oscillation caused by ac magnetic field - Google Patents

Abstract

PURPOSE:To remove the variation of position (oscillation) of electron beams caused by an AC magnetic field which is an external disturbance in an electron beam device such as an electron beam drawing device. CONSTITUTION:The border of a mark 85 on a stage is found by an electron beam, an adequate size of area beam is set and radiated, a reflected electron generated from the above border is detected by a detector 70, and a noise is removed and the electron is stored in a correcting signal 40. Then, it is read and a deflection signal in which the oscillation of the electron beam 82 is minimized is given to a deflector 84. And an AC magnetic field on the periphery of a mirror body 80 is detected by an AC magnetic field processor 60, and when it exceeds a specific value, the operation of the device stops temporarily, and the above correction process is carried out again.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam apparatus such as an electron beam drawing apparatus used for manufacturing a semiconductor device and the like, and more particularly to a method and apparatus for eliminating vibration of an electron beam due to an alternating magnetic field. Is.

[0002]

2. Description of the Related Art An electron beam is, by its nature, susceptible to a disturbance magnetic field. For example, if there is an alternating magnetic field in a direction crossing the passage of the electron beam, the electron beam is deflected and the position thereof is changed, which deteriorates the drawing accuracy. The alternating magnetic field is generated by an electric cable, an electric device or the like arranged in the building. For this reason, most of the conventional devices have an electron beam path made of a ferromagnetic material such as permalloy so as not to be easily affected by an AC magnetic field, but it is difficult to completely remove the effect. For this reason, when installing the electron beam device, it was necessary to prepare an environment for reducing the alternating magnetic field.

However, even if the AC magnetic field around the device is large,
Since it is better if it is small around the mirror body, from this point of view, a method of reducing the AC magnetic field around the mirror body is disclosed in JP-A-60-91541 and JP-A-58-21425.
No. 6 publication. Further, a method of detecting an alternating magnetic field and deflecting an electron beam so as to eliminate vibration is disclosed in JP-A-57-103253 and JP-A-59-12735.
1, JP-A-59-146144, and JP-A-62.
It is disclosed in each publication of No. 12044. Further, a method of directly detecting the vibration of the electron beam and deflecting the electron beam based on the detected waveform signal to correct it is also disclosed in Japanese Patent Laid-Open No. 59-127352.

[0004]

However, in the above-mentioned prior art, there is no mention of the size of the electron beam when the magnitude of the vibration of the electron beam due to the alternating magnetic field is obtained. The size of the electron beam used is an important factor in accurately detecting the amount of vibration of the electron beam, and cannot be ignored. In addition, there is no description on the operability for accurately stopping and irradiating the electron beam at the boundary portion of the mark having high contrast, and further, the detection method and countermeasures when the peripheral alternating magnetic field fluctuates are not touched at all. It wasn't done.

The present invention has been made in order to solve these problems. The vibration of the electron beam due to the external disturbance AC magnetic field is accurately detected and corrected, and the vibration of the electron beam due to the AC magnetic field is corrected. It is an object of the present invention to provide a removing method and device.

[0006]

In order to achieve this object, in the present invention, first, the size of the electron beam for irradiating the mark is set to be larger than the oscillation width of the electron beam due to the alternating magnetic field, and the electron beam Thus, the electron beam is automatically stopped and irradiated on the mark boundary portion having a high contrast by scanning the mark, and the deflection of the electron beam is corrected and controlled based on the generated signal waveform to eliminate the vibration of the electron beam. At this time, noise included in the obtained signal waveform is removed, and a correction control signal for removing vibration is superimposed on the deflector of the electron beam based on the shaped signal waveform.

Further, an AC magnetic field detector is provided around the electron beam apparatus to constantly measure the strength of the AC magnetic field in the surroundings, and the fluctuation amount becomes larger than a value at the time of previous correction by a certain fixed value or more. In that case, the operation of the electron beam apparatus is temporarily suspended, the above-described vibration removing operation is performed, the strength of the alternating magnetic field at that time is stored, and the operation of the electron beam apparatus is restarted.

[0008]

In the method and apparatus for eliminating the vibration of the electron beam due to the alternating magnetic field, the electron beam is stopped and irradiated at the boundary portion of the marks having sharp edges of different substances,
The backscattered electrons that are generated are detected and the vibration state of the electron beam that vibrates due to the alternating magnetic field is measured. At this time, in order to perform accurate measurement, first, it is necessary to accurately align the vibration center of the electron beam with the boundary portion of the mark, and then, determine the size of the electron beam from the vibration width of the electron beam. So that at least part of the electron beam
It is necessary to always illuminate the boundary of the mark. This is because if the size of the electron beam is smaller than the oscillation width of the electron beam, at some point the electron beam will deviate from the boundary of the mark and irradiate only a single material surface. This is because the amount of backscattered electrons becomes constant despite the change in the position of the electron beam. That is, even when the electron beam is oscillating in, for example, a sine wave shape, the signal waveform of the generated backscattered electrons has a trapezoidal shape with a flat head. Therefore, the waveform and amplitude of the electron beam vibration cannot be accurately measured from this waveform. Therefore, in the present invention, when measuring the vibration of the electron beam, the size of the electron beam is set to be larger than the vibration width, the vibration waveform of the electron beam is accurately detected, and the electron beam vibration is detected based on this signal waveform. Vibration is eliminated by superimposing a correction control signal on the deflection system.

By the way, the AC magnetic field outside the mirror body for oscillating the electron beam is not always constant, but may sometimes fluctuate greatly. Therefore,
Even if the vibration of the electron beam is corrected and removed at a certain point in time, if the state of the external AC magnetic field changes, the electron beam again vibrates. Therefore, in the present invention, an AC magnetic field detector is provided in the periphery of the mirror body to constantly measure the AC magnetic field. Then, when the strength of the magnetic field changes above a certain value, the operation of the electron beam apparatus is temporarily interrupted, and the operation of removing the vibration of the electron beam according to the changed AC magnetic field is performed. The operation of the electron beam device is restarted.

In this way, the oscillation of the electron beam due to the alternating magnetic field is eliminated, and the external alternating magnetic field is always detected, so that the operation of eliminating the oscillation of the electron beam is repeated in response to the change. This enables stable operation of the electron beam apparatus, and, for example, in the case of an electron beam drawing apparatus, high-precision drawing is possible.

[0011]

【Example】

(Embodiment 1) This embodiment relates to a method and apparatus for eliminating the vibration of an electron beam due to an alternating magnetic field according to the present invention.
The basic device configuration and operation will be described with reference to FIGS.

First, in FIG. 1, the drawing control unit 10 controls the stage 91 so that the mark 85 is formed immediately below the electron beam 82.
To move. After that, the drawing control unit 10 controls the deflector 84 via the deflecting unit 30, and the mark 8 is generated by the electron beam 82.
5 scan over. This state is shown in (1) of FIG. The shaded area is a mark, the left is Si (silicon), the right is W
(Tungsten). By the scanning, the reflected electrons shown by the waveform (2) in FIG. 2 are generated from the mark 85. When this is detected by the detector 70 and binarized by the comparator level 51 shown in the waveform (2) of FIG. 2 in the signal processing unit 50,
2 (3) is obtained. Therefore, when the scanning pitch of the electron beam is p and the number of shots when changing from 0 to 1 in FIG. 2C is N, p × N is the magnitude of the deflection for irradiating the boundary portion of the mark. is there. When this data (p × N) is given to the deflecting unit 30, the electron beam 82 can be stopped and irradiated at the boundary of the mark 85, as shown in FIG.

When the electron beam is stopped and irradiated on the mark boundary portion having a different contrast, for example, in the case of a mark composed of different materials shown in FIG. 2A, the backscattering coefficient for incident electrons of Si (silicon) is about 14. %, While W (tungsten) is as large as about 50%, contrast occurs. Therefore, when the electron beam fluctuates left and right around the boundary, this vibration can be detected as a change in the intensity of the reflected electrons. In order to detect vibration with the best contrast, it is desirable that the electron beam be small in size. However, if it is too small, the electron beam will deviate from the boundary, vibration will not be detected, and the state of vibration cannot be accurately obtained. On the contrary, when the electron beam is extremely large, there arises a problem that the signal contrast is lowered.

In order to solve this problem, in the present invention, first, the beam size setting unit 20 and the shaping deflector 83 detect the size of the electron beam for mark detection and its setting accuracy of about 0.05 μm. And irradiate the boundary. At this time, if the electron beam vibrates more than 0.05 μm at 50 Hz, for example, the reflected electron signal at the boundary becomes a trapezoidal waveform (5) with a period of 20 ms in FIG. The trapezoid is formed because the beam irradiates the site where the intensity of the reflected electrons does not change beyond the boundary, and the vibration waveform is not correct. Therefore, in order to obtain a correct vibration waveform, the drawing control unit 10 uses this trapezoidal waveform (see FIG.
The beam size setting unit 20 is controlled so that (5)) has a sinusoidal waveform ((6) in FIG. 2), and the size of the electron beam is expanded. As a result, a waveform (6) that faithfully reproduces the state of vibration can be obtained.

Next, assuming that the electron beam 82 sways in the oscillation cycle of the power supply frequency, the oscillation of the electron beam 82 is detected as a change in the intensity of the reflected electron signal as shown by the waveform (6) in FIG. It In the vibration waveform (6) detected by the detector 70, harmful noise is removed by the correction signal unit 40,
By controlling the polarity and the amplitude, the deflection unit 30 acts so as to stop the vibration of the electron beam 82. On the other hand, the correction signal unit 40 has a function of holding a signal for correcting the vibration, and after the above operation for obtaining an appropriate correction signal is completed, the correction signal unit 40 repeatedly reads the signal in a cycle synchronized with the power source and outputs the deflection signal of the deflection unit 30. Add to. As a result, the vibration of the electron beam 82 due to the alternating magnetic field in the power supply cycle is continuously corrected.

On the other hand, when the series of operations are completed, the drawing control unit 10 issues a command to the AC magnetic field processing unit 60 to detect the AC magnetic field waveform in the vicinity of the electron beam mirror 80 and store it as an initial value. The AC magnetic field processing unit 60 reads out the stored waveform at the power supply cycle and, at the same time, subsequently compares it with the AC magnetic field waveform constantly detected, and if the magnetic field strength or the waveform is different, draw control The section 10 is notified that an abnormality has occurred. When the strength of the magnetic field around the apparatus changes over time, the drawing control unit 10 interrupts the drawing operation, moves the stage 91, and repeats the procedure from waveform (1) in FIG.

In this way, if the oscillation of the electron beam due to the AC magnetic field is eliminated and the strength of the AC magnetic field changes,
The vibration of the electron beam is automatically corrected again. As a result, it is possible to eliminate the position variation of the electron beam due to the AC magnetic field around the electron beam apparatus or the AC magnetic field generated by the AC current flowing in the mirror body.

(Embodiment 2) FIG. 3 shows an embodiment in which the method and apparatus for eliminating the vibration of an electron beam according to the present invention is applied to a variable shaped beam type electron beam drawing apparatus. In the present embodiment, an AC magnetic field around the apparatus is detected, and the deflection of the electron beam is corrected based on the detected AC magnetic field. The operability is improved by adding a means for irradiating and a means for detecting the beam position variation with an optimum signal-to-noise ratio.

First, in the mirror body 80, the electron beam generated by the electron gun 81 is formed by forming apertures 87 and 88 having openings.
With the variable shaping deflector 83, the variable shaping beam 82 having a variable area is formed. The deflection and focus of the electron beam 82 are controlled by a deflector 84 and an objective lens coil 89, and a standard mark 85 on the wafer mounted on the sample stage 91 is irradiated. In addition to these, there are deflectors and coils inside the mirror body, but they are omitted because they are not related to the present invention. In the figure, an AC magnetic field detector 63 for detecting an AC magnetic field, an amplifier 62, a switch 61, an adder 32,
And DAC 21, amplifier 22, and signal processing circuit 5
1 and its peripheral circuit section 50 are constituent elements according to the present invention.

The drawing control unit 10 controls the stage 91 via the stage control unit 90 to set the standard mark 85 directly below the electron beam 82. Next, the drawing control unit 10
Sets data in the DAC (D / A converter) 21 so that the size of the electron beam 82 is set to a predetermined size. The predetermined size in this case means that the electron beam is X
The size is required to determine the boundary portion of the mark by scanning in the (Y) axis direction, and to stop and irradiate the electron beam at the boundary portion based on the result.
As a specific example, it is approximately 0.05 μm. Thereafter, the drawing controller 10 turns on the electron beam 82 and simultaneously controls the deflector 84 via the DAC 31 and the adder 32 to sequentially scan the mark including the boundary in the X-axis direction at the scanning pitch p. The switch 61 is turned off.
The reflected electron signal generated from the mark 85 by scanning is
The SSD detector (semiconductor detector) 70 detects the waveform as shown in FIG. 2- (2), and the signal processing unit 50 uses the method already described with reference to FIG.
XN) is calculated. The calculated deflection amount is set in the DAC 31 via the drawing controller 10. This makes it possible to automatically stop and irradiate the electron beam 82 at the boundary of the mark 85.

Hereinafter, it is assumed that the electron beam 82 oscillates with an amplitude larger than 0.05 μm by an alternating magnetic field of 50 Hz. Here, the monitor 3 has a function similar to that of an oscilloscope, and has a function of observing the output of the SSD detector 70 as a waveform. Therefore,
The state of vibration can be observed on the screen of the monitor 3.
When the vibration width of the vibration is larger than 0.05 μm, a trapezoidal wave as shown in FIG. A trapezoidal wave with a squashed head is caused by the vibration width of 0.
Since it is larger than 05 μm, Si or W other than the boundary part
This is because the intensity of reflected electrons does not change even if the electron beam vibrates in this portion. In the case of such a trapezoidal wave, the drawing controller 10 is operated to increase the data given to the beam size setting unit 20 to increase the size of the electron beam. Then, the waveform observed on the monitor screen is adjusted so as to be a sine wave that does not collapse the head as shown in FIG. 2- (6). That is, the distortion of the vibration waveform due to the poor measurement is eliminated. Here, the monitor 3 has a function of simultaneously displaying the waveforms of two channels, and the amplifier 62 is connected to the remaining one input.
The output of the AC magnetic field detector 63 is input, and the AC magnetic field waveform of the place where the AC magnetic field detector 63 is placed can be monitored. Here, the AC magnetic field detector 63 detects an AC magnetic field waveform around the device and corrects the deflection of the electron beam by using the detected AC magnetic field waveform.
This is an AC magnetic field sensor for stopping the vibration of the electron beam. However, it is well known that when a metal such as iron is placed in an atmosphere of an alternating magnetic field, distortion occurs in the vicinity of the metal and the state changes depending on the place.
Therefore, if the place where the AC magnetic field detector 63 is placed is selected while observing the two waveforms on the monitor 3, a waveform approximately similar to the oscillation waveform of the electron beam can be obtained.

When the switch 61 is turned on at an arbitrary timing, the AC magnetic field detector 63 detects the magnetic field at the place where the coil is placed. Therefore, the amplifier 62 and the switch 6
1, the electron beam is deflected with a waveform and magnitude corresponding to the peripheral magnetic field via the adder 32. This state can be observed on the monitor 3. When the gain of the amplifier 62 is adjusted under such a condition, the amplitude of the vibration waveform increases or decreases. This is because the phase is different by 180 degrees when it becomes larger, so that the front and back of the coil of the AC magnetic field detector 63 are reversed and the phase is shifted by 180 degrees.
If the phases match, the gain of the amplifier 62 is adjusted so that the amplitude of the waveform on the monitor 3 screen becomes the minimum. By the above operation, for example, the correction in the X-axis direction is completed.
Although omitted in the figure, the same configuration as above is provided for the Y axis. Therefore, the Y axis is also adjusted in the same manner as above. With the configuration and method detailed above, it is possible to automatically stop the electron beam and irradiate the boundary portion of the mark, and
By optimizing the size of the electron beam, a faithful vibration waveform without distortion can be monitored, and the vibration of the electron beam due to the AC magnetic field can be removed with a simple configuration.

(Embodiment 3) FIG. 4 shows another embodiment in which the apparatus for eliminating the oscillation of an electron beam due to an alternating magnetic field according to the present invention is applied to a variable shaped beam type electron beam drawing apparatus. In the present embodiment, the deflection of the electron beam is corrected by using the vibration itself of the detected electron beam, rather than the means for detecting the AC magnetic field around the mirror body by the magnetic field detector to correct the deflection of the electron beam. Is to do.

First, it is assumed that the boundary portion of the mark has already been obtained by the procedure and operation described in the above embodiment, and the electron beam 82 is irradiated to this boundary portion. The size of the electron beam at this time is about 0.05 μm, and
It is assumed that the electron beam vibrates with a vibration width larger than this. The backscattered electron signal indicating the vibration is detected by the SSD sensor 70 and input to the filter 401. The filter 401 is a general bandpass filter,
It is a constant that allows the frequency of the Hz component to pass. As a result, harmful noise components are removed from the vibration waveform of the electron beam, and the vibration waveform is written in the memories 403 and 409 via the ADC (AD converter) 402. Although a bandpass filter is used in this embodiment, addition averaging or smoothing processing may be performed.

Here, the memory 409 is used to hold a correction signal waveform for correcting the vibration of the electron beam,
The memory 403 is used to temporarily hold the vibration waveform.
When writing data in these two memories 403 and 409, addresses are repeated in synchronization with the power supply cycle. 40
Blocks 5 to 408 show an example of a circuit that generates an address in synchronization with a power supply. The AC line signal for synchronization is binarized by the binarization circuit 408, and the MM (short stable pulse generator) 407 is triggered at the rising timing thereof. The output resets the address of the counter 406 to zero. On the other hand, a pulse of 50 kHz (20 μs) period is input from the oscillator 405 to the clock input of the counter 406. With these, the counter 406 becomes
It is possible to generate address data synchronized with the power supply.

The addresses of the two memories 403 and 409 are incremented by 50 μs in steps of 20 μs.
Since it is cleared to zero in the cycle of 1
The vibration waveform of the cycle is stored. When at least 20 ms has elapsed, the drawing control unit 10 stops writing in the memory 403 and reads the waveform in the memory 403. If the read waveform is trapezoidal as shown in FIG. 2- (5), predetermined data is set to the beam size setting unit 20 so that the electron beam 82 becomes large. The procedure of writing and reading the vibration waveform in the memory according to the above procedure is shown in Figure 2-
Repeat until the sine wave of (6) is obtained. If a proper beam size is required, fix this beam size,
The drawing control unit 10 reads out and stores the contents of the memory 403. With this series of operations, it is possible to automatically obtain a vibration waveform from which noise is removed.

After the series of operations are completed, the drawing control unit 10 turns off the beam 82 once, enables writing of the output of the ADC 402 only to the memory 403, resets the memory 409, and causes the amplifier 411 to write. Set an appropriate gain. After these preparations are completed, the beam is turned on for about 20 ms. Since the address of the memory 409 is constantly incremented at a cycle of 50 Hz synchronized with the power supply, the waveform already stored in the memory 409, that is, the vibration waveform is read out in synchronization with the power supply, and the DAC 410, the amplifier 411, and the polarity inversion are performed. Vessel 412,
The electron beam 82 is deflected by the deflector 84 via the adder 32.
Vigorously vibrate. Then, the reflected electron signal generated from the boundary portion of the mark 85 is stored in the memory 403 as described above. After at least 20 ms has elapsed, the drawing control unit 1
0 turns off the beam, switches the MPX 404, and reads the contents of the memory 403. If it is smaller than the amplitude of the vibration waveform that has already been stored, the amplifier 41
Increase the gain of 1. Then, the same procedure is repeated to find the optimum gain of the amplifier 411. If no solution is obtained, the polarity inverter 412 is set to the opposite polarity. That is, the polarity of the vibration correction signal is inverted. Then, the above procedure is repeated. According to the above method, since the electron beam is directly corrected by the vibration waveform itself, the vibration can be almost completely stopped.

When these are completed, the drawing control unit 10
Issues a command to the AC magnetic field processing unit 60 to store the current AC magnetic field waveform. That is, the AC magnetic field processing unit 60
Is a detector 6 for detecting the AC magnetic field around the electron beam mirror.
3, an amplifier 62, an ADC 64, a memory 65 for holding the detected AC magnetic field waveform, and a comparison circuit 67. The address of the memory 65 is controlled by the output of the counter 406. Therefore, the address is incremented in steps of 20 μs and is zero-cleared at a cycle of 50 Hz. Therefore, as the AC magnetic field waveform detected by the detector 63, a waveform for one cycle synchronized with the power supply is stored. If at least 20 ms has elapsed, the drawing control unit 1
0 prohibits writing to the memory 65, reads it out, and inputs it to one input terminal of the comparison circuit 67. The output of the ADC 64 is always input to the other input of the comparison circuit 67. The comparison circuit 67 is a window comparator,
It has a function of outputting an abnormal signal to the drawing control unit 10 when the difference between the two amplitudes becomes larger than a predetermined value.

After that, when the strength of the AC magnetic field around the mirror body changes, the drawing controller 10 detects an abnormal signal from the comparison circuit 67 and interrupts the drawing operation. Then, after performing a series of operations for eliminating the vibration of the electron beam described above, the contents of the memory 65 are rewritten. After that, the normal drawing operation is continued.

When these operations in the X-axis direction are completed, the drawing controller 10 controls the stage controller 90 to control the mark 8
5 is moved in the Y-axis direction. Although not shown in the figure, the same procedure is executed for the vibration of the electron beam on the Y axis using the correction circuit having the same configuration as that for the X axis.

The embodiments shown in FIGS. 1, 3 and 4 were applied to a variable shaping type electron beam drawing apparatus. However, for example, there is also a spot beam type drawing apparatus that draws an electron beam as a thin beam with a diameter of about 10 nm. In such a device, it may be difficult to accurately stop and irradiate the electron beam on the boundary portion of the mark. However, in the present invention, the beam is fixed and irradiated to the boundary portion of the marks having different electron reflectivities, and the position variation of the electron beam is known based on the intensity change of the reflected electrons. That is, it does not have to be the focal point.

From this point of view, an example implemented in a spot beam type drawing apparatus will be described with reference to FIG. First, the drawing control unit 10 slightly shifts the exciting current of the objective lens coil 89 from the optimum value via the lens power supply 1. That is,
Set to defocus. As a result, the area of the electron beam 82 on the mark 85 increases. As a result, the area beam becomes the same as that of the variable shaped electron beam writing apparatus, and it becomes possible to irradiate the electron beam on the boundary portion of the mark. If the beam size is changed with the objective lens, the larger the beam size, the lower the current density of the electron beam,
The signal to noise ratio is slightly reduced. As a countermeasure, although not shown in the figure, a circuit for fetching the same waveform a number of times using the memories 403 and 409 and performing an averaging process is provided. Actually, the signal processing unit 50 is also provided with an averaging processing circuit similar to the above (not shown in the figure).

In each of the embodiments described in detail above, the vibration of the electron beam is obtained by detecting the intensity change of the reflected electron signal when the electron beam is stopped and irradiated at a specific portion of the mark made of a different material. The same effect can be obtained by using marks made of the same material and having a convex or concave sectional shape. Further, the signal for detecting vibration may detect secondary electrons. Alternatively, the intensity change of the transmitted electrons may be obtained by using a plate having an opening and setting the boundary portion as a specific portion.

The present invention relates to an electron beam device having a function of deflecting an electron beam, for example, a scanning electron microscope,
The present invention can be applied to all of these devices such as a length measuring SEM, an electron microscope having a deflection function, and a charged beam device using an ion beam.

[0035]

As described above, in the method and apparatus for eliminating the oscillation of the electron beam due to the alternating magnetic field according to the present invention, the boundary portion of the mark having a high contrast is irradiated with the electron beam having a proper beam size. By doing so, the vibration of the electron beam due to the alternating magnetic field can be measured, and the vibration of the electron beam is removed by superimposing the correction control signal on the deflection system of the electron beam based on the obtained vibration waveform. In the beam drawing apparatus, it is possible to manufacture a highly accurate semiconductor device.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of an apparatus for removing vibration of an electron beam due to an alternating magnetic field according to the present invention.

FIG. 2 is an explanatory diagram regarding a vibration waveform obtained in the apparatus shown in FIG.

FIG. 3 is a basic configuration diagram of an apparatus according to a second embodiment of the present invention.

FIG. 4 is a basic configuration diagram of an apparatus according to a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Drawing control part 20 ... Beam size setting part 30 ... Deflection part 40 ... Correction signal part 50 ... Signal processing part 60 ... AC magnetic field processing part 70 ... Detector 80 ... Electron beam mirror 81 ... Electron gun 82 ... Electron beam 83 , 84 ... Deflector 85 ... Mark 90 ... Stage control unit 91 ... Stage

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kimiaki Ando 1-280, Higashi Koikekubo, Kokubunji, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd.

Claims (6)

[Claims] 1. A boundary portion of a mark having a high contrast is irradiated with an electron beam to detect vibration of the electron beam due to an alternating magnetic field, and the deflection amount of the electron beam is corrected and controlled based on the detected vibration amount. In the method for eliminating the vibration of the electron beam due to the alternating magnetic field in the electron beam device, the size of the electron beam for irradiating the mark to detect the vibration is set to be larger than the width of the vibration of the electron beam due to the alternating magnetic field. A method for removing oscillation of an electron beam due to an alternating magnetic field, which is characterized by the above. 2. A boundary portion of a mark having a high contrast is irradiated with an electron beam to detect vibration of the electron beam due to an alternating magnetic field, and the deflection amount of the electron beam is corrected and controlled based on the detected vibration amount. In the device for removing the oscillation of the electron beam due to the alternating magnetic field in the electron beam device, the electron beam is automatically moved to the boundary portion of the mark based on the mark signal obtained by scanning the mark with the electron beam. Based on a signal waveform obtained by setting irradiation means, setting the size of the electron beam larger than the oscillation width of the electron beam due to the alternating magnetic field, and the signal waveform obtained by irradiation of the boundary part of the mark with the electron beam, Device for eliminating oscillation of an electron beam due to an alternating magnetic field, characterized in that it comprises means for correcting and controlling beam deflection. 3. A noise removing means for removing noise included in a signal waveform obtained by irradiating a boundary portion of the mark with the electron beam, and deflection of the electron beam based on the signal waveform shaped by the noise removing means. The device for eliminating vibration of an electron beam due to an alternating magnetic field according to claim 2, further comprising: a means for superposing a correction control signal for eliminating vibration due to the alternating magnetic field. 4. An AC magnetic field detector is provided around the electron beam apparatus, and the AC magnetic field detector stores the strength of the AC magnetic field at the time when the oscillation of the electron beam is removed,
Thereafter, the fluctuation of the alternating magnetic field around the electron beam device is constantly measured, and compared with the stored strength of the alternating magnetic field, and when the magnitude of the fluctuation exceeds a certain value, The apparatus for removing vibration of an electron beam due to an alternating magnetic field according to claim 2 or 3, wherein the operation for removing the vibration of an electron beam due to an alternating magnetic field is reset. 5. When the magnitude of the fluctuation of the AC magnetic field around the electron beam device exceeds a certain value, the operation of the electron beam device is temporarily stopped to prevent the oscillation of the electron beam by the AC magnetic field. The operation for removing is reset, and when the operation for removing the vibration is completed, the strength of the AC magnetic field around the electron beam apparatus is stored again, and the operation of the electron beam apparatus is restarted. The device for removing vibration of an electron beam due to an alternating magnetic field according to claim 4. 6. An electron beam drawing apparatus for manufacturing a semiconductor device, comprising an apparatus for removing oscillation of an electron beam due to an alternating magnetic field according to any one of claims 2 to 5.