JPH1196950A - Method and device for radiating highly stable charged particle beam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily provide a beam having the same radiation characteristics as those before replacement in the event that a charged particle source is replaced, and generate a beam whose beam radiation characteristics such as beam current value, beam size, and irradiation position, are stable for a long time, when a field emission type charged particle source is used. SOLUTION: Potential of a lead-out electrode 1 is controlled to stabilize current of a beam 11 at a predetermined constant value while the potential of the lead-out electrode is read during operation of a field emission type charged particle source, and the operating conditions for optical systems 8, 13 for beam generation are changed based on the reading. Relations between the potential of the lead-out electrode and the operating conditions for the optical systems are found previously, as relations for obtaining desired beam irradiation characteristics, for example, a beam free from beam drift and beam fuzziness, by calculation or experiment, and stored in a storage device.

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 utilizing apparatus using a field emission type charged particle source, and in particular, to generate an irradiation beam having a stable current value, beam size and irradiation position for a long time. The present invention relates to a charged particle beam irradiation method and a charged particle irradiation apparatus that can perform the method.

[0002]

2. Description of the Related Art A minute portion of a sample can be processed by irradiating a sample with a charged particle beam such as an ion or an electron focused on a thin beam by an optical system. In this case, it is necessary to narrow the beam to a thickness of about nanometer, so that a field emission type charged particle source is used as the radiation source. A liquid metal ion source is used in a fine processing apparatus using an ion beam, and a field emitter is used in a processing apparatus using an electron beam. These field emission type charged particle sources have the feature of high brightness, but have the problem that the emission current value changes sensitively to changes in the surface state of the charged particle source.

Therefore, for example, in an apparatus such as a micro-machining apparatus using an ion beam, which needs to generate a beam of a stable current for several hours, the electric field intensity acting on the ion source in response to a change in the current value And measures are taken to obtain a stable current. With this method, an ion beam with a stable current value can be obtained.

The field emission type charged particle source is provided with an extraction electrode for applying a strong electric field to the charged particle source. Further, an electrode called a control electrode may be further disposed on the side of the extraction electrode on the charged particle source side. In the present specification, these extraction electrodes and control electrodes are collectively referred to as field emission voltage application electrodes.

[0005]

However, when the potential of a field emission voltage applying electrode such as an ion extraction electrode is changed in order to change the electric field strength acting on the ion source, the action strength of the lens formed by the electrode is changed. Changes, the irradiation position of the beam irradiating the sample changes (hereinafter, referred to as beam drift), and the beam becomes thicker (hereinafter, referred to as beam blur). Therefore, in order to perform high-precision processing with a conventional processing apparatus, processing is occasionally interrupted, and beam drift is corrected by detecting a mark engraved on the sample in advance, or beam defocusing is performed using an autofocus method. Or need to be removed.

However, especially in an ion beam application apparatus, application of these methods often causes a problem. That is, since the mark detection and the auto focus are performed by irradiating the sample to be processed with the beam, the sample is damaged. When mark detection is repeated, the sample is often damaged so that even the mark cannot be discriminated, and drift correction cannot often be performed.

In a charged particle irradiation apparatus provided with a field emission type charged particle source, a charged particle source deteriorated by use is often replaced. Since the charged particle source that has been replaced usually differs from the charged particle source before replacement in terms of its surface condition, mounting position, spacing between the extraction electrode, etc., the applied voltage of the field emission voltage applying electrode such as the extraction electrode must be changed. If the charged particle source is kept the same as before the exchange, a beam current of a desired magnitude cannot be obtained in many cases. Even if the charged particle source is not replaced, if the shape and the surface state of the particle source are significantly changed, a desired beam current cannot be obtained with the same field emission voltage application electrode potential. Therefore, the voltage applied to the field emission voltage application electrode is adjusted to a different value.
However, when the potential of the field emission voltage application electrode is changed,
The intensity of the lens formed by the electrode changes and the imaging magnification of the entire optical system changes, so that the beam may not be focused as much as before the charged particle source is replaced. Therefore, if a situation occurs in which the required field emission voltage application electrode potential is significantly different, open the vacuum device and change the mounting position of the charged particle source, or readjust the optical system to increase the imaging magnification. It was necessary to return to the original value.

The present invention has been made in view of such problems of the prior art, and a first object of the present invention is to provide a method for applying a field emission voltage applying electrode for obtaining a desired beam current when the potential of the electrode is largely changed. Another object of the present invention is to provide a charged particle beam irradiation method and apparatus capable of easily obtaining a beam having the same irradiation characteristics as before the change. Further, a second object of the present invention is to use a field emission type charged particle source and perform beam irradiation characteristics such as a beam current value, a beam size, and an irradiation position for a long time without relying on a mark detection or an autofocus method. Is to provide a charged particle beam irradiation method and apparatus capable of generating a stable beam.

[0009]

In order to achieve the first object, according to the present invention, an operating condition of an optical system for giving desired beam irradiation characteristics to various values of a field emission voltage application electrode potential is provided. Is obtained in advance by calculation or experiment, and the relationship between the field emission voltage application electrode potential and the operating condition is stored in the storage means of the charged particle beam irradiation apparatus in the form of a table. When the necessary field emission voltage application electrode voltage changes and the beam irradiation characteristics deteriorate, the operating conditions of the optical system are changed with reference to this table.

In order to achieve the second object,
In the present invention, first, a field emission voltage application electrode potential reading device is installed in a charged particle beam irradiation device. And
During the beam irradiation, the voltage application electrode potential for field emission is periodically read, and the operating conditions of the optical system are set so that the beam irradiation characteristics are the same as those at the start of the beam irradiation with reference to the above table. adjust. Therefore, in order to achieve the second object of the present invention, in order to periodically read the potential of the field emission voltage applying electrode, and to instruct to change the operating condition of the optical system from the read value and the storage means. Need a control device to perform.

That is, the present invention provides a charged particle beam irradiating method for irradiating a sample by squeezing a charged particle extracted from a field emission type charged particle source by an optical system under the action of a field emission voltage applying electrode and irradiating the charged particle beam to a sample. The relationship between the potential of the field emission voltage application electrode that gives the beam irradiation characteristics and the operating conditions of the optical system is determined in advance, and the field emission voltage application electrode potential is read when a charged particle beam is generated, and the read field emission is read. The optical system is controlled in accordance with the optical system operating condition obtained by applying the application voltage application electrode potential to the above relationship.

Further, the present invention provides a field emission type charged particle source, a field emission voltage applying electrode for applying an electric field to the charged particle source, and an optical system for narrowing a charged particle beam extracted from the charged particle source. And a storage means for storing a relationship between a potential of a field emission voltage applying electrode for providing a desired beam irradiation characteristic and an operating condition of an optical system, and a method for obtaining a desired beam current. Control means for controlling the optical system based on operating conditions obtained using the potential of the voltage applying electrode for field emission and the relationship stored in the storage means.

The relationship between the potential of the field emission voltage applying electrode that gives desired beam irradiation characteristics and the operating conditions of the optical system is as follows.
The information can be stored in the storage unit in the form of a mathematical expression, a table, or the like. The optical system may include at least two lenses, in which case the correction of the beam blur can be performed by controlling at least one of the lenses, for example, controlling the objective lens. The lens can be an electrostatic lens or a magnetic lens.

Further, the present invention provides a charged particle beam irradiation method for irradiating a sample by narrowing down charged particles extracted from a field emission type charged particle source by an optical system by the action of a field emission voltage application electrode and irradiating the charged particle beam to a sample. The relationship between the potential of the field emission voltage applying electrode that gives the beam irradiation characteristics and the operating conditions of the optical system is stored, and the beam current is stabilized by controlling the potential of the field emission voltage applying electrode. The optical system is controlled in accordance with operating conditions obtained by applying the potential of the field emission voltage application electrode to the above relationship.

Further, the present invention provides a field emission type charged particle source, a field emission voltage applying electrode for applying an electric field to the charged particle source, and an optical system for narrowing a charged particle beam extracted from the charged particle source. In a charged particle beam irradiation apparatus including: a storage means for storing a relationship between a potential of a field emission voltage applying electrode that provides a desired beam irradiation characteristic and an operating condition of an optical system; Beam current stabilizing means for controlling and stabilizing a beam current; and control for controlling an optical system based on an operating condition obtained by using a potential stored in the storage means and a potential of a field emission voltage applying electrode. Means.

The optical system can include at least two lenses. In this case, only the correction of the beam blur can be performed by controlling at least one of the lenses, for example, the objective lens. The control means can correct both the beam drift and the beam blur by controlling a lens other than the lens facing the beam irradiation sample, for example, a condenser lens.

The control means can control the optical system so that the imaging magnification of the optical system is kept constant. The control means is such that the apparent charged particle source viewed from the beam focusing lens facing the beam irradiation sample is maintained at a fixed position.
The optical system may be controlled. According to the present invention, a predetermined beam current can be obtained by controlling the potential of the field emission voltage application electrode. In addition, since the operating conditions of the optical system are changed in conjunction with the change in the potential of the field emission voltage application electrode, when the charged particle source is replaced, a beam having the same irradiation characteristics as before the replacement can be easily obtained. The beam current value,
A beam having stable beam irradiation characteristics such as a beam size and an irradiation position can be generated.

According to the charged particle beam irradiation method or the charged particle beam irradiation apparatus of the present invention, a beam having stable irradiation characteristics can be obtained for a long time, so that a sample can be processed with high processing accuracy.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing an example of a charged particle beam irradiation device according to the present invention. This figure shows a state in which the sample is being processed by irradiating the sample with an ion beam to form an L-shaped depression.

This charged particle beam irradiation apparatus includes a liquid metal ion source 2 which is a field emission type charged particle source, an extraction electrode 1 for applying a strong electric field to the liquid metal ion source 2, and an ion beam extracted from the ion source 2. An accelerating electrode 7 for accelerating 3 to a predetermined energy, a condenser lens 8 for adjusting the imaging magnification of the optical system, a beam scanner 12 for controlling a beam irradiation position on the sample, and an object for focusing an ion beam on the sample 14. A lens 13 is provided. The liquid metal ion source 2 is connected to an acceleration power supply 25. The extraction electrode 1, the condenser lens 8, and the objective lens 13 are each provided with an extraction voltage power supply 26,
Power is supplied from a condenser lens power supply 27 and an objective lens power supply 28, and each power supply 25 to 28 is controlled by the general controller 5.

When a high voltage of 6 to 11 kV (hereinafter referred to as an extraction voltage) is applied between the extraction electrode 1 and the liquid metal ion source 2, the ion beam 3 is extracted from the liquid metal ion source 2. The current value of the ion wire 3 is controlled by changing the extraction voltage applied from the extraction voltage power supply 26 to the extraction electrode 1. In order to stabilize the current value, in this example, the general controller 5 reads the current value of the ion beam 3 using the ammeter 4 and
The output voltage of the extraction voltage power supply 26 is adjusted so that the value becomes a predetermined constant value. The ion beam 3 extracted from the ion source 2 is applied to the accelerating electrode 7 maintained at the ground potential for about 30 minutes.
It is accelerated to have energy of kev and enters the condenser lens 8.

In this example, the potentials of the extraction electrode 1 and the acceleration electrode 7 are set to approximately 7 kV and 30 kV, respectively, based on the potential of the liquid metal ion source 2. Since the potentials of the extraction electrode 1 and the acceleration electrode 7 are significantly different from each other, a lens action also occurs at the portions of the extraction electrode 1 and the acceleration electrode 7, and the trajectory of the ion beam is bent as shown in the figure. The extraction electrode 1 and the acceleration electrode 7
After that, the lens formed by
I will call it. It goes without saying that the strength of the lens action of the extraction / acceleration lens 9 changes due to a change in the potential of the extraction electrode 1.

The ion beam 11 entering the condenser lens 8 through the aperture receives the lens action of the condenser lens 8 and passes through the beam scanner 12 and enters the objective lens 13. By controlling the beam scanner 12,
The sample irradiation position of the beam is controlled. When viewed from the position of the objective lens 13, actually, the tip of the virtual image 10 of the liquid metal ion source formed by the lens action of the extraction / acceleration lens 9 and the condenser lens 8 as if the ion beam 11 emitted from the liquid metal ion source 2 was formed Looks out of the box. The ion beam 11 entering the objective lens 13 is focused by the objective lens 13 and irradiates the sample 14. Here, the lens action strength of the objective lens 13 is adjusted, and an extremely fine ion beam is obtained under the condition that the real image of the virtual image 10 of the ion source is formed on the sample 14.

In the example shown in FIG. 1, the sample 14 is irradiated with the ion beam 11 for about 3 hours in order to form a target L-shaped depression in the sample 14. The processing accuracy, that is, the accuracy of the finished shape of the processing is determined by the fineness of the ion beam 11 and the stability of the irradiation position. During irradiation of the beam for about 3 hours, if the beam is not kept narrow, the beam will lose its shape. If the sample irradiation position of the ion beam 11 changes without permission, the processed shape is shifted from the target shape. Also, if the beam current value changes during processing, the digging depth will be different.

As described above, the principle of generating an ultrafine beam of this ion beam processing apparatus is that the optical system including the extraction / acceleration lens 9, the condenser lens 8, and the objective lens 13 is composed of the liquid metal ion source 2. Just a real image,
Since the condition is set so as to focus and project on the position of the sample 14, if the operating conditions of the extraction / acceleration lens 9, the condenser lens 8 and the objective lens 13 do not change during operation. Both the fineness of the beam and the irradiation position do not change and are maintained at a constant value.

However, in the apparatus shown in FIG. 1, in order to stabilize the beam current value, the current value of the ion beam 3 is read by the ammeter 4, and the extraction electrode is instructed by the general controller 5 to keep the value constant. 1 voltage is changed. When the voltage of the extraction electrode 1 is changed, the intensity of the lens action of the extraction / acceleration lens 9 changes, and the image of the ion source that was initially formed at the position 10 changes to the position 15 at a different magnification from the image formation position. It comes to tie. Since the objective lens 13 is adjusted to project 10 images onto the sample 14, when the ion source image changes from 10 to 15, the objective lens 13 projects the 15 image onto the sample 14 out of focus. . That is, the beam for irradiating the sample 14 becomes thick.

Further, when the liquid metal ion source 2 is displaced from the central axis 22 of the optical system as shown in the figure, the axis deviation distance of 15 becomes larger than the axis deviation distance of 10, and 15 The beam irradiating position on the sample 14 projecting the image 10 is further away from the central axis 22 as compared with the case where 10 is projected. That is, the draw-out / acceleration lens 9
The ion source image moves due to the change in the imaging magnification of
The beam irradiation position on the sample 14 changes.

As described above, in an apparatus in which the ion source 2 has a misalignment, when the extraction voltage applied to the extraction electrode 1 changes, both beam blur and beam drift occur. Therefore, in this example, when the characteristics of the extraction / acceleration lens 9 change due to a change in the potential of the extraction electrode 1, the characteristics of the condenser lens 8 are changed in accordance with the amount of the change to compensate for the change in the characteristics of the entire optical system. doing. That is, the overall controller 5 reads the potential V _E of the extraction electrode 1 and uses the voltage correspondence table created in advance and stored in a storage device or the like inside the overall controller 5 to operate the operating voltage V _{C of the} condenser lens 8.
Is changing. Table 1 shows an example of the voltage correspondence table.

[0029]

[Table 1]

The preparation of the voltage correspondence table was performed as follows using the principle of calculation of the lens characteristics. First, the extraction voltage V
It is necessary to calculate the position of the image 15 of the ion source formed by the extraction / acceleration lens 9 for various values of _E , and then return the position of the image 15 to the original design value of position 10. calculating the a condenser lens voltage V _C. For example, even when the extraction voltage V _E changes to 8kV from 7 kV, the voltage V _C of the condenser lens 8 from the original 6kV 5.755
When the voltage is changed to kV, the position of the image 10 of the ion source does not change, and neither the imaging magnification nor the focus of the entire optical system changes. Thus, for some values of the extraction voltage V _E, it calculates the overall optical system imaging magnification and without changing the focus condenser lens voltages V _C, respectively.

Since the amount of change in the extraction voltage V _E required for current stabilization is infinite, it is not possible for the general controller 5 to determine a new condenser lens voltage V _C with reference to Table 1. Here, the relationship shown in Table 1 is approximated as in the following equation [Equation 1], and when the extraction voltage V _E is read, the condenser lens voltage V _C is obtained using this equation.

[0032]

V _C (V) = 6.72 × 10 ⁻⁵ × V _E ² (V) −1.3
1 × V _E (V) +11900 This embodiment is characterized in that the extraction voltage is corrected in order to obtain a beam having a stable current value and stable beam irradiation characteristics throughout the entire process of about 3 hours. And the correction of the lens action strength of the optical system. In the example shown in the figure, the beam current is detected by detecting the total current drawn from the liquid metal ion source 2 with the ammeter 4, but the sample is irradiated by connecting the ammeter 29 to the sample 14. The current value of the ion beam 11 is measured directly, and the extraction electrode 1 is determined based on the current value.
By compensating for the potential of, a higher-performance correction can be performed.

FIG. 2 shows an example of a sample for a transmission electron microscope manufactured using the ion beam irradiation apparatus according to the present invention shown in FIG. In this processing, both sides of the initially rectangular parallelepiped sample block 33 are shaved off by the ion beam 11 to form a thin film region 34 having a thickness of about 50 nm at the center. In the transmission electron microscope, the electron beam is transmitted through the region 34 of the thin film for observation. Because of the necessity of transmitting an electron beam, the thickness of the thin film region 34 is desired to be as thin as possible. 5
When trying to finish to a thickness of as thin as 0 nm, in a conventional apparatus that does not use the present invention, the beam irradiation position and the beam thickness cannot be controlled, and as a result, the center of the thin film is often cut off as shown in FIG. there were.

FIG. 4 is an explanatory view showing another example of the charged particle beam irradiation apparatus according to the present invention. FIG. 4 shows an example in which the present invention is applied to an electron beam micromachining apparatus. This electron beam micromachining apparatus includes a field emitter 18 which is a field emission type electron beam source, and an extraction electrode for applying a strong electric field to the field emitter 18. 1. an accelerating electrode 7 for accelerating an electron beam 19 extracted from a field emitter 18 to a predetermined energy;
Axis shift corrector 20 for correcting the axis shift of the electron beam, condenser lens 8 for adjusting the imaging magnification of the optical system, sample 1
A beam scanner 12 for controlling a beam irradiation position on 4;
An objective lens 13 for focusing an electron beam on a sample 14 is provided. The field emitter 18 is connected to an acceleration power supply 25. The extraction electrode 1 and the objective lens 13 are supplied with power by an extraction voltage power supply 26 and an objective lens power supply 28, and the power supplies 25, 26, 28 are controlled by the general controller 5. A high resistance 21 is provided between the extraction voltage power supply 26 and the extraction electrode 1.
And an ammeter 4 are connected, and the output of the ammeter is
Has been entered.

By applying a high voltage between the extraction electrode 1 and the field emitter 18, the field emitter 18
An electron beam 19 is emitted from the tip of the. Most of the electron beam 19 emitted into the solid angle range of about π steradians flows into the extraction electrode 1, passes through the high-resistance 21, passes through the ammeter 4, and enters the extraction voltage power supply 6.

The high resistance 21 is provided for stabilizing the current value of the electron beam 19. In the apparatus example of FIG. 1, the voltage of the extraction electrode 1, ie, the output voltage of the extraction voltage power supply 26, is controlled by the general controller 5 so that the current value of the ion beam 3 emitted from the liquid metal ion source 2 becomes constant. Although the current value was stabilized by adjusting, the output voltage of the extraction voltage power supply 26 was maintained at a constant value in the example of the device of FIG. 4, and the current value was stabilized by the extraction voltage self-compensation method using the voltage drop by the high resistance 21. Is being done. That is, when the surface state of the field emitter 18 changes and the electron emission ability decreases, the electron beam 19 flowing into the extraction electrode 1 decreases and the voltage drop due to the high resistance 21 also decreases.
The emission current value applied between the electrode 8 and the extraction electrode 1 attempts to return to the original value.

In the apparatus of this example, unlike the apparatus of FIG. 1, the output voltage of the extraction voltage power supply 26 is maintained at a constant value.
Can not be read directly across controller 5 is the potential V _E of the lead electrode 1 from extracting voltage supply 26. Therefore, in order to know the value of the extraction electrode potential V _E, it reads a current value I _E flowing in the ammeter 4 to the extraction electrode 1, to obtain an extraction electrode potential V _E using the following expression (2). Here, _VE0 and R are the output voltage value of the extraction voltage power supply 26 and the resistance value of the high resistance 21, respectively.

[0038]

[Number 2] _{V E = V E0 -R × I} E electron beam 19 passing through the center pores of the lead electrode 1 is accelerated by the accelerating electrode 7 and enter the axial deviation corrector 20. The axis misalignment corrector 20 is a device that finely adjusts the traveling position of the electron beam 31 to make the mechanical misalignment of the field emitter 18 apparently zero. This axis misalignment corrector 2
If the axis deviation of the field emitter 18 is corrected in advance using 0, no beam drift occurs due to a change in the extraction voltage.

Therefore, in this apparatus, only beam blur correction is performed. That is, since the magnification correction of the optical system is not necessary in the beam blur correction, the operating characteristics of the objective lens 13 are changed in accordance with the change in the extraction voltage, and only the defocus is corrected. That is, the overall controller 5 outputs the output voltage value V _E0 of the extraction voltage power supply 26 and the current value I _E flowing into the extraction electrode 1.
_E is read, and the magnetic field type objective lens 1 is calculated by the following equation (Equation 3).
3 to obtain a new coil current value I _O ,
8 and supply it to the objective lens 13. [Equation 3] is
It is created in the same way as when [Equation 1] is obtained from Table 1,
A and b in [Equation 3] are constants for approximating the relationship between V _E and I _O by a mathematical expression. In this example, the relationship between V _E and I _O is 1
Although the approximation was made by the following equation, the correction effect is more remarkable if a method of approximation is made by a quadratic equation as shown in [Equation 1].

[0040]

I _O = a × (V _E0 −R × I _E ) + b The apparatus shown in FIG. 1 and the apparatus shown in FIG. 4 reflect the basic requirements of the optical system necessary for implementing the present invention. It has become something. That is, since the correction of the beam drift of the present invention is performed by correcting the imaging magnification of the optical system, the optical system that generates the charged particle beam includes at least two or more lenses whose characteristics can be arbitrarily controlled. Need to be. An optical system composed of only one lens cannot arbitrarily change the imaging magnification. On the other hand, beam blur correction is performed by focusing correction of the optical system, so that only one lens whose focal length can be controlled is required.

Here, a method of continuously generating a beam having stable beam irradiation characteristics such as a beam current value, a beam size, and an irradiation position over a long period of time using an ion beam irradiation apparatus and an electron beam fine processing apparatus as an example will be described. did. However, the present invention is not limited to the case where the charged particle beam is continuously generated, and even when the charged particle source is exchanged, the beam current control by controlling the potential of the extraction electrode, By controlling the optical system using the relationship [3], a beam having the same irradiation characteristics as before the charged particle source exchange can be easily obtained.

Although a field emission type charged particle source having only an extraction electrode has been described as an example, the present invention is similarly applied to a field emission type charged particle source having an extraction electrode and a control electrode. be able to. In this case, to correspond to the Table 1 of the lead electrode potential V _E is a combination of the control electrode potential and extraction electrode potential.

[0043]

According to the present invention, a field emission type charged particle source is used, and when the potential of a field emission voltage applying electrode such as an extraction electrode potential for obtaining a desired beam current is greatly changed, the same as before the change. A beam having irradiation characteristics can be easily obtained. In addition, a beam having stable beam irradiation characteristics such as a beam current value, a beam size, and an irradiation position can be generated for a long time without depending on a mark detection or an autofocus method.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of a charged particle beam irradiation device according to the present invention.

FIG. 2 is a diagram showing an example of a sample for a transmission electron microscope manufactured using the ion beam irradiation apparatus according to the present invention.

FIG. 3 is a diagram showing an example of a microfabricated sample using a conventional processing apparatus.

FIG. 4 is an explanatory view showing another example of the charged particle beam irradiation device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Extraction electrode, 2 ... Liquid metal ion source, 3 ... Ion beam,
4 ... Ammeter, 5 ... General controller, 7 ... Acceleration electrode, 8 ... Condenser lens, 9 ... Extraction / acceleration lens, 10 ... Ion source image, 11 ... Ion beam, 12 ... Beam scanner, 13
... Objective lens, 14 ... Sample, 15 ... Ion source image when the extraction voltage changes, 18 ... Field emitter, 19 ...
Electron beam, 20: misalignment corrector, 21: high resistance, 22: central axis of optical system, 25: acceleration power supply, 26: extraction voltage power supply, 2
7: condenser lens power supply, 28: objective lens power supply,
29: ammeter, 31: electron beam, 33: sample block, 34: thin film area, 35: central part of thin film

Claims (10)

[Claims] 1. A charged particle beam irradiation method in which charged particles extracted from a field emission type charged particle source by the action of a field emission voltage applying electrode are finely squeezed by an optical system to irradiate a sample with a desired beam irradiation characteristic. The relationship between the potential of the field emission voltage applying electrode and the operating condition of the optical system is determined in advance, and the potential of the field emission voltage applying electrode is read when a charged particle beam is generated. A charged particle beam irradiation method, wherein the optical system is controlled in accordance with an optical system operating condition obtained by applying a voltage application electrode potential to the relationship. 2. A charged particle beam irradiation method in which charged particles extracted from a field emission type charged particle source by the action of a field emission voltage applying electrode are finely squeezed by an optical system to irradiate a sample with a desired beam irradiation characteristic. The relationship between the potential of the field emission voltage applying electrode and the operating conditions of the optical system is stored, and the beam current is stabilized by controlling the potential of the field emission voltage applying electrode. A charged particle beam irradiation method, wherein the optical system is controlled according to operating conditions obtained by applying the potential of the field emission voltage application electrode to the relationship. 3. A charged particle source of a field emission type, a voltage application electrode for field emission for applying an electric field to the charged particle source, and an optical system for narrowing a charged particle beam extracted from the charged particle source. In a charged particle beam irradiation apparatus, a storage means for storing a relationship between a potential of the field emission voltage application electrode for providing a desired beam irradiation characteristic and an operation condition of the optical system, and a storage means for obtaining a desired beam current Control means for controlling the optical system based on operating conditions obtained using the potential of the field emission voltage application electrode and the relationship stored in the storage means. Irradiation device. 4. A field emission type charged particle source, a field emission voltage applying electrode for applying an electric field to the charged particle source, and an optical system for narrowing a charged particle beam extracted from the charged particle source. In a charged particle beam irradiation apparatus, a storage means for storing a relationship between a potential of the field emission voltage applying electrode that gives a desired beam irradiation characteristic and an operating condition of the optical system; and a potential of the field emission voltage applying electrode. Beam current stabilizing means for controlling the beam current by controlling the potential of the field emission voltage applying electrode and the operating condition obtained using the relationship stored in the storage means. A charged particle beam irradiation apparatus, comprising: control means for controlling. 5. A charged particle beam irradiation apparatus according to claim 3, wherein said optical system includes at least two lenses. 6. A charged particle beam irradiation apparatus according to claim 5, wherein said control means controls at least one lens constituting said optical system to correct beam blur. 7. A charged particle beam irradiation apparatus according to claim 5, wherein said control means corrects both the beam drift and the beam blur by controlling a lens other than the lens facing the sample for beam irradiation. Charged particle beam irradiation equipment. 8. A charged particle beam irradiation apparatus according to claim 4, wherein said control means controls said optical system such that an imaging magnification of said optical system is kept constant. Irradiation device. 9. The charged particle beam irradiation apparatus according to claim 4, wherein the control means controls the apparent charged particle source as viewed from a beam focusing lens facing the beam irradiation sample to be kept at a fixed position. A charged particle beam irradiation apparatus characterized by controlling an optical system. 10. A micromachined sample prepared by using the charged particle beam irradiation apparatus according to claim 3. Description: