JP2007258272A - Ion beam processing method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a processing pattern according to a desire without providing a corrugated shape on a material to be exposed. <P>SOLUTION: In an ion beam processing method for forming a predetermined pattern on the material W to be exposed by irradiating the same portion of the material W to be exposed with an ion beam a plurality of times, if a current value of the ion beam periodically ripples, a cycle T of the ripple is obtained, an ion beam in which a phase is shifted by a phase δ calculated from the cycle T is prepared for the emitted ion beam, and the same portion of the material to be exposed is re-irradiated with the ion beam having the shifted phase to form the predetermined pattern. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ion beam processing method and an ion beam processing apparatus for irradiating an exposed material with an ion beam to form a desired microstructure on the exposed material.

  2. Description of the Related Art In recent years, a process called LIGA (Lithographie, Galvanoforming and Abforming) has been used for the production of molds used in microfabrication apparatuses such as nanoimprints. The LIGA process has an excellent feature that an aspect ratio (ratio of processing depth to processing width) can be increased (Non-Patent Documents 1 and 2).

Since this LIGA process uses a proximity X-ray mask to transfer a pattern to a resist layer (polymethyl methacrylate: PMMA), the proximity X-ray mask must be manufactured separately, and the cost for that must be estimated. Has the problem. In addition, the use of X-rays increases equipment costs, and strict safety management is required during operation.
In order to solve these problems, an ion beam processing apparatus is disclosed in which a pattern is directly exposed on a resist layer by a beam of light ions such as hydrogen ions (protons), helium ions, or lithium ions without using a mask ( Patent Document 1).
Special table 2001-50369 gazette LIGA process, http://www.ritsumei.ac.jp/se/~sugiyama/research/re_5.1.html Mold by synchrotron radiation, http://staff.aist.go.jp/k.awazu/Japanese-folder/nanoimprint1021.htm

However, the ion beam machining apparatus using light ions disclosed in Patent Document 1 has the following problems.
That is, when an ion beam is irradiated to a material to be exposed to form a processing pattern as shown in FIG. 2A, the edge in the width direction actually undulates (regularly as shown in FIG. 2B). It became clear that the shape changed. As a result of repeated studies and examinations on this phenomenon, the inventors of the present application have determined that the cause is that the current value of the irradiated ion beam fluctuates periodically (sometimes referred to as pulsation). . When the pulsation of the current value of the ion beam has substantially the same frequency as the frequency (50 Hz or 60 Hz) of the commercial AC power supply supplied to the ion beam processing apparatus, particularly the ion beam irradiation apparatus that generates the ion beam. I found that there are many.

In the electric / electronic field, periodic noise due to commercial AC power is often generated at the output of the apparatus, and is called “hum” or “hum noise”. That is, in the conventional ion beam processing apparatus, pulsation caused by hum noise is generated in the irradiated ion beam.
The present invention has been made in view of the above-described problems, and even if there is a change in the ion beam irradiated to the material to be exposed, it is desired to have no wavy shape on the material to be exposed. An object is to provide an ion beam processing method and an ion beam processing apparatus capable of forming a pattern.

In order to achieve the above object, the present invention takes the following technical means.
That is, the technical means according to the present invention provides an ion beam processing method in which a predetermined pattern is formed on the exposed material by irradiating the same portion of the exposed material with the ion beam a plurality of times. When the value fluctuates periodically, the period T of the fluctuation is obtained,
Prepare an ion beam whose phase is shifted by the phase δ calculated from the period T with respect to the previously irradiated ion beam, and again irradiate the ion beam whose phase is shifted to the same location on the exposed material, A predetermined pattern is formed.

By this technical means, the phase is shifted by the phase δ calculated from the fluctuation period T with respect to the pattern of the material to be exposed which has been waved by the previous ion beam irradiation (that is, the position of the peaks and valleys of the waveform is shifted). ) Irradiation with an ion beam makes it possible to make the wavy shape of the pattern after irradiation uniform.
Preferably, the phase δ is set to δ = T / n when the pattern is formed by irradiating the material to be exposed n times.

By doing so, the phase of the ion beam irradiated each time is shifted by δ = T / n. For example, the position of the valley of fluctuation in the previously irradiated ion beam corresponds to the position corresponding to the current or next time. The peak of the ion beam to be irradiated comes to correspond, and finally it is possible to prevent the waveform from being generated in the pattern.
Further, the technical means of the present invention is an ion beam processing method in which a predetermined pattern is formed on the exposed material by irradiating the same position of the exposed material multiple times with the ion beam. Is periodically changed, the period T of the fluctuation is obtained, a reference beam wave that periodically fluctuates in the period T is set, and only the phase δ calculated from the period T is set for the reference beam wave. An ion beam having a phase shift is prepared, and the ion beam having a phase shift is irradiated again on the same portion on the exposed material to form a predetermined pattern.

By this technical means, the phase is shifted by the phase δ calculated from the fluctuation period T with respect to the pattern of the material to be exposed which has been waved by the previous ion beam irradiation (that is, the position of the peaks and valleys of the waveform is shifted). ) Irradiation with an ion beam makes it possible to make the wavy shape of the pattern after irradiation uniform.
Preferably, when forming the pattern by irradiating the material to be exposed n times with respect to the reference beam wave, the pattern is formed with respect to the reference beam wave. An ion beam shifted by δ = (T / n) × (m−1) is prepared, and the ion beam whose phase is shifted may be irradiated to the same portion on the exposed material.

By doing so, the phase of the ion beam irradiated each time is shifted by δ = T / n. For example, the position of the valley of fluctuation in the previously irradiated ion beam corresponds to the position corresponding to the current or next time. The peak of the ion beam to be irradiated corresponds, and finally, it can be prevented that the processing pattern has a wave shape.
Further, the technical means according to the present invention is an ion beam processing apparatus for forming a predetermined pattern on the exposed material by irradiating the same position of the exposed material with the ion beam a plurality of times. When the value fluctuates periodically, pulsation detecting means for obtaining the fluctuation period T and an ion beam whose phase is shifted by the phase δ calculated from the period T with respect to the ion beam previously irradiated are prepared. And a scan control means for controlling to irradiate the same position on the exposed material again with the ion beam whose phase is shifted.

  The ion beam processing apparatus described above sets pulsation detecting means for obtaining the fluctuation period T when the current value of the ion beam fluctuates periodically, and a reference beam wave that fluctuates periodically in the period T. A reference beam wave setting unit and an ion beam whose phase is shifted by a phase δ calculated from a period T with respect to the reference beam wave are prepared, and the ion beam whose phase is shifted is the same on the material to be exposed. Scan control means for controlling to irradiate the spot again.

  By using the ion beam processing method and the ion beam processing apparatus according to the present invention, it is possible to form a desired processing pattern without having a corrugated shape on the material to be exposed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an ion beam processing apparatus 1 according to the present invention. The vertical direction in this figure is the vertical direction of the apparatus, the horizontal direction in the figure is called the horizontal direction, and the direction penetrating the figure is called the front-back direction.
The ion beam processing apparatus 1 includes an ion beam irradiation apparatus 3, an ion beam controller 4, an exposed material support stage 5, a current measurement probe 6, a Faraday cup 7, a calculator 2, a chamber 8, and a vacuum controller 9. .

The ion beam irradiation apparatus 3 includes an ion source 10, an accelerator 11, and a focusing device 12 that are disposed on the upper side in the chamber 8.
The ion source 10 generates proton ions (H ⁺ ), which are light ions, by applying a voltage between a sharp metal tip and the surroundings in a hydrogen atmosphere. The accelerator 11 arranged on the lower side of the ion source 10 includes a plurality of extraction electrodes 13 stacked, and performs the function of extracting and accelerating ions generated in the ion source 10 in a certain direction (downward).

Below the accelerator 11, there is provided a focusing device 12 that energizes to form a predetermined electromagnetic field, focuses the proton ions extracted from the ion source 10 and accelerated, and irradiates a predetermined position of the material to be exposed W. The focusing device 12 includes a magnifying lens 14, a deflector 15, and a focusing lens 16.
Each of the magnifying lens 14 and the focusing lens 16 is composed of a wound electromagnetic coil. Depending on the magnetic field distribution and magnetic field strength, proton ions passing through the center are attracted and expanded in the radial direction, or the center of the ion beam. It can be pushed back to the shaft side and focused. The deflector 15 is composed of two sets of parallel electrode plates that are shifted by 90 degrees from each other. By applying a DC voltage corresponding to a desired degree of beam deflection to each set of electrode plates, the axis of the ion beam is deflected. Move to deflect.

The ion beam controller 4 is provided outside the chamber 8. The ion beam controller 4 is formed by the focusing device 12 by adjusting the voltage applied to the focusing device 12 (magnifying lens 14, deflector 15, focusing lens 16). Controls the degree of ion beam focusing and irradiation position.
The exposed material support stage 5 is provided in the chamber 8 and is used to place the exposed material W to be processed by the ion beam processing apparatus 1. The exposed material support stage 5 includes a small stage 17 on which the exposed material is directly placed and a large stage 18 that supports the small stage 17. The small stage 17 is configured to be able to move freely on the large stage 18 in the front-rear and left-right directions in minute units (for example, on the order of 10 nm) by a driving device (not shown). The large stage 18 is configured so as to be largely movable between a position where the material to be exposed W is exposed to the ion beam and a position where it is not exposed by a driving device (not shown).

A Faraday cup 7 can be arranged on the upper side of the above-described exposed material support stage 5 and on the lower side of the focusing device 12.
The Faraday cup 7 receives all of the ion beam and measures the number of all ions in the ion beam as a current value. The Faraday cup 7 is configured to be movable between a position where the driving device 20 receives an ion beam (light receiving position) and a position where the ion beam is not received (retreat position). A known Faraday cup 7 is used.

In the ion beam processing apparatus 1 of the present embodiment, the current measuring probe 6 can be inserted around the light receiving position of the exposed material support stage 5 when the exposed material support stage 5 is positioned at the retracted position. Yes.
The current measuring probe 6 is for measuring the charge of ions forming the ion beam as a current value, and is arranged with the detection surface facing the ion beam irradiation device 3 side. The current measurement probe 6 is configured such that the detection surface can scan the inside of the ion beam in two orthogonal directions (front-rear direction and left-right direction) on the horizontal plane, and scanning in these two directions is coupled to the current measurement probe 6. Further, it is performed by a driving device including a piezo element (not shown), a feed mechanism, and the like that extend and contract in directions orthogonal to each other.

  As shown in FIG. 1, the current measuring probe 6 is arranged so that the detection surface is substantially at the same position in the vertical direction as the exposure surface of the material to be exposed W placed on the small stage 17. Further, the current measuring probe 6 is driven by a driving device (not shown) so as not to come into contact with the exposed material W or the exposed material support stage 5 when the exposed material W moves to the exposure position on the large stage 18. The entire current measurement probe 6 is configured to move to the retracted position.

  The computing unit 2 controls the movement of the material support stage 5 (small stage 17 and large stage 18), scans the current measuring probe 6, and moves the Faraday cup 7, and the Faraday cup 7 and the current measuring probe 6 It has a function of storing the received current value and calculating the center position of the focused ion beam, the range of the ion beam, and the distribution of the number of ions from the current value and the integrated value.

  Further, the ion beam processing apparatus 1 according to the present embodiment detects a periodic fluctuation (sometimes referred to as pulsation) of the current value of the ion beam and also includes a pulsation detecting means 40 for obtaining the pulsation period T. 2 is provided. This pulsation detecting means 40 is composed of a digital or analog FFT processing circuit, and the current value of the ion beam measured by the Faraday cup 7 is input to the above-described FFT processing circuit, and after the frequency analysis, The period T is obtained.

  In the ion beam controller 4, when the material to be exposed W is irradiated with the ion beam a plurality of times, the phase is shifted by the phase δ calculated from the pulsation period T with respect to the pulsation of the ion beam irradiated last time. While preparing an ion beam, a scan control means 41 for controlling the ion beam irradiation device 3 and the exposed material support stage 5 (small stage 17) so that the same spot on the exposed material W can be irradiated again. Is provided.

In addition, reference beam wave setting means 42 for setting and storing a reference beam wave that fluctuates in the above-described pulsation period T is also provided.
The computing unit 2 is realized by a personal computer or workstation, a control program executed on them, an interface having an A / D or D / A conversion function, or the like.

  The chamber 8 is a pressure vessel that accommodates the ion beam irradiation device 3, the material to be exposed support stage 5, the current measurement probe 6, and the Faraday cup 7 described above. A vacuum gauge 33 is attached to the chamber 8, and the chamber 8 includes a rotary pump for roughing and a turbo molecular pump for vacuuming in the middle vacuum range. The internal pressure can be adjusted.

The vacuum controller 9 opens and closes the automatic valve 34 connected to the vacuum device or the automatic valve 35 for leaking based on the measurement value by the vacuum gauge 33, so that the chamber in the processing of the exposed material W by the ion beam is performed. Maintain the vacuum in 8 appropriately.
Consider a case where a predetermined processing pattern is formed on the material to be exposed W using the ion beam processing apparatus 1 described above.

First, as a preparation before processing, the vacuum controller 9 controls the automatic valve 34 and the leakage automatic valve 35 connected to the vacuum apparatus, and the inside of the chamber 8 is in a vacuum state (for example, 1 × 10 ⁻⁵ Pa or less). Hold on.
Thereafter, the current value of the ion beam by the Faraday cup 7 is measured. At that time, the current measuring probe 6 is moved to the retracted position, and then the Faraday cup 7 is moved to the light receiving position. The ion beam controller 4 excites the ion source 10 and energizes the magnifying lens 14, the deflector 15, and the focusing lens 16 to form a predetermined electromagnetic field, and directs the focused ion beam toward the Faraday cup 7. To irradiate.

The computing unit 2 detects the measured current value from the Faraday cup 7 according to the number of irradiated ions, determines whether the current value is equal to or greater than a predetermined value, and predicts the surface of the exposed material, for example. When the ion beam current density considering the irradiation area is 10 μA / cm ² or more, it is determined that the ion beam is focused.
It is very preferable to obtain the center position of the ion beam and the distribution of the number of ions by scanning the current measuring probe 6 at the beam focusing position after the ion beam focusing.

After the completion of setting the conditions, the workpiece W is processed by irradiating the workpiece W with an ion beam.
First, the current measuring probe 6 is retracted to the retracted position so as not to come into contact with the Faraday cup 7, and instead, the Faraday cup 7 is moved to a position for receiving the ion beam to temporarily block the ion beam.

Next, the large stage 18 is moved by the driving device to a position where the material to be exposed W placed on the small stage 17 is irradiated with the ion beam. Then, based on the calculated position information of the center of the ion beam, the small stage 17 is moved by the driving device so that the center of the ion beam hits a desired position of the material to be exposed W placed on the small stage 17. Adjust to.
When the adjustment of the position of the small stage 17 is completed, the Faraday cup 7 is retracted to a position where the ion beam is not received, and the ion beam is scanned by moving the small stage 17 in a state where the ion beam is irradiated onto the exposed material. A desired processing pattern is formed. The exposure time or the scanning speed of the ion beam (the moving speed of the small stage 17) is controlled by the scanning control means.

Here, consider a case where a linear pattern (elongated rectangular pattern) is formed on the material to be exposed W as shown in FIG.
In the case of the present embodiment, the current value of the ion beam measured by the Faraday cup 7 or the like is affected by the frequency of the commercial AC power supplied to the ion beam processing apparatus 1, and with time as shown in FIG. It has become pulsating. Therefore, when the time average current value of the pulsating ion beam is set to a predetermined value and the material to be exposed is scanned only once with the ion beam, the processing width is a period as shown in FIGS. 2 (b) and 3 (b). Will fluctuate. At the same time, the machining depth also varies as shown in FIG. Since the fluctuations in the machining width and the machining depth are caused by fluctuations in the current value of the ion beam, the cycle is substantially the same as the fluctuation cycle T of the current value in the ion beam.

In order to avoid such inconvenience, in the case of the present embodiment, the processing is performed according to the procedure shown in FIG.
First, as part of preparation before processing, the pulsation detecting means 40 calculates the pulsation period T of the ion beam captured by the Faraday cup 7. Since the fluctuation is caused by the frequency of the commercial AC power supply, in the case of Western Japan, it is assumed that the cycle T≈ 1/60 (sec). [S51, S52]
Thereafter, the number of times of repeated drawing (scanning times) n of the processing pattern is calculated from the relationship between the current value of the ion beam and the dose required for processing the exposed material W. [S53]
In particular,
(i) Since it is considered that the current value at the extreme end H (see FIGS. 2 and 6) of the processing pattern of the material to be exposed is the smallest, the time average value of the ion current value there is I (A).

(ii) The minimum dose amount _Dmin necessary for forming a desired pattern is calculated.
That is, assuming that the processing width of the processing pattern is d (m) and the maximum scanning speed of the ion beam is V (m / s), the processing area is d × V (m ² / sec). Since the current value on the processed surface is at least I (A) as calculated in (i), the minimum dose amount D _min is D _min = I / (d × V) (C / m ² ).

(iii) The number of scans n required for processing is calculated.
That is, from the total dose D and the minimum dose D _min ,

n = D / D _min = D / (I / (d × V)) (1)
It becomes.
Next, the shift amount (phase) δ when shifting the ion beam is calculated from the number of repeated scans n obtained in (iii) and the fluctuation period T of the current value of the ion beam.

δ = T / n (sec) (2)
Calculate with [S54]

After performing the above calculation, the ion beam is scanned at the maximum scanning speed V from the left to the right, for example, along the processing pattern as shown in FIG. The small stage 17 on which the material to be exposed W is directly placed is moved from the right to the left at the maximum speed V). At this time, with respect to the first (previous) ion beam scan, the second (current) ion beam scan focuses on the same location (for example, the left edge H) on the exposed material, and the waveform phase is δ. Only shifted. [S55]
For example, if the total number of scans is 4, the first ion beam is irradiated with an ion beam whose phase is shifted by T / 4, and the third time is a phase with respect to the second ion beam. Is irradiated with an ion beam shifted by T / 4. The fourth time may be irradiated with an ion beam whose phase is shifted by T / 4 with respect to the third ion beam.

  Since the frequency of the pulsation of the ion beam is caused by the frequency of the commercial AC power supply, it can be considered to be substantially constant. Therefore, when the frequency of pulsation is 60 Hz, phase δ = (1/60) × (1/4) ≈4.17 msec. Therefore, the ion beam delayed by 4.17 msec with respect to the first ion beam may be irradiated for the second time. An ion beam delayed by 4.17 msec from the second ion beam may be irradiated for the third time, and so on.

  As a result, the first ion beam is regarded as a reference beam wave, and the second time is irradiated with an ion beam whose phase is shifted by (T / 4) × 1 with respect to the reference beam wave. The third time is irradiation with an ion beam whose phase is shifted by (T / 4) × 2. For the fourth time, an ion beam whose phase is shifted by (T / 4) × 3 with respect to the reference beam wave may be irradiated. In other words, when forming the pattern by irradiating the material to be exposed n times, in the case of m-th (m ≦ n) ion beam irradiation, the phase δ = An ion beam shifted by (T / n) × (m−1) may be irradiated.

Since the pulsation of the current value of the ion beam is often caused by a commercial AC power supply, it can be approximated by a sine wave, and the phase δ of the pulsation waveform is

δ = 2π / n (rad) (3)
It can also be calculated by

  In this case, for example, if the total number of scans is 4, the second ion beam is irradiated with a phase shifted by π / 2 the third time, and the third ion beam is irradiated with the second ion beam. Then, an ion beam whose phase is shifted by π / 2 is irradiated. The fourth time may be irradiated with an ion beam whose phase is shifted by π / 2 with respect to the third ion beam.

The first ion beam is used as a reference beam wave. The ion beam whose phase is shifted by (π / 2) × 1 is irradiated the second time with respect to the reference beam wave, and the phase is (π / 2) × for the third time. An ion beam shifted by 2 is irradiated. The fourth time may be irradiated with an ion beam whose phase is shifted by (π / 2) × 3.
By doing so, the ion beam whose phase is shifted by the phase δ calculated from the pulsation period T, that is, the position of the peaks and valleys of the waveform is shifted, is irradiated to the processing pattern that has become wavy by the previous ion beam irradiation. Thus, the wavy shape of the processing pattern can be made uniform.

In order to ensure the technique described above, it is necessary to sequentially irradiate the same spot on the material to be exposed with an ion beam whose phase is shifted by δ.
For this purpose, for example, attention is paid to the left edge H of the processing pattern. The ion beam irradiated for the first time has an intermediate current value ((maximum value + minimum value) / 2, phase δ = 0) at the left edge H. The ion beam to be irradiated for the second time is timed so that the current value at the left edge H becomes the minimum value (valley, phase δ = π / 2) using the scan control means 41, and the left of the machining pattern. Irradiate from right to left. The timing of the ion beam irradiated for the third time is adjusted by using the scan control means 41 so that the current value becomes an intermediate value ((maximum value + minimum value) / 2, phase δ = π) at the left edge H. The irradiation is performed from the left to the right of the processing pattern. For the ion beam irradiated for the fourth time, the scan control means 41 is used to adjust the timing so that the current value becomes the maximum value (peak portion, phase δ = 3π / 2) at the left edge portion H, and the left of the machining pattern. Irradiate from right to left.

FIG. 6 shows a situation in which ion beams are sequentially irradiated by the method described above. As can be seen from this figure, even if the current value of the ion beam pulsates and the processing width or the like undulates in one scan, the processing pattern of the processing width d is obtained by a plurality of scans (four times). Is reliably formed.
The present invention is not limited to the above embodiment.

  Although the scanning direction of the ion beam has been described from left to right, it may be from right to left, or may be alternately scanned from left to right in the first time and from right to left in the second time. In any case, the ion beam irradiation device 3 and the exposed material are scanned by the scan control means 41 so that the ion beam shifted by the phase δ based on the pulsation period T can be irradiated to the same location on the exposed material W. The support stage 5 may be controlled.

The total number of scans for forming the processing pattern may be any number, and is not limited to four.
Further, for example, the ion beam irradiation device 3, the ion beam controller 4, the exposed material support stage 5, the current measuring probe 6, the Faraday cup 7, the arithmetic unit 2, the chamber 8, and the vacuum controller 9 are included in the present invention. It can be changed appropriately according to the purpose.

  The present invention can be used in an ion beam processing apparatus that irradiates a material to be exposed with an ion beam to form a desired microstructure on the material to be exposed.

It is a block diagram of the ion beam processing apparatus which concerns on this invention. It is the figure which showed the process pattern formed on the to-be-exposed material. It is the figure which showed the fluctuation | variation state of the electric current value of an ion beam, the fluctuation | variation state of the process width of a process pattern, and the process depth. It is the figure which showed the condition which irradiates an ion beam, shifting a phase. It is the flowchart which showed the process sequence concerning this invention. It is the conceptual diagram which showed that a processing pattern was formed by irradiating an ion beam, shifting a phase.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ion beam processing apparatus 2 Calculator 3 Ion beam irradiation apparatus 4 Ion beam controller 5 Exposure object support stage 6 Current measurement probe 7 Faraday cup 8 Chamber 9 Vacuum controller 10 Ion source 11 Accelerator 12 Focusing device 17 Small stage 18 Large Stage 40 Pulsation detection means 41 Scan control means 42 Reference beam wave setting means W Material to be exposed

Claims (6)

In the ion beam processing method for forming a predetermined pattern on the material to be exposed by irradiating the same location of the material to be exposed multiple times with the ion beam,
When the current value of the ion beam fluctuates periodically, the fluctuation period T is obtained,
Prepare an ion beam whose phase is shifted by the phase δ calculated from the period T with respect to the previously irradiated ion beam,
An ion beam processing method, wherein a predetermined pattern is formed by irradiating the same portion of the material to be exposed again with the ion beam whose phase is shifted.   2. The ion beam processing method according to claim 1, wherein the phase δ is set to δ = T / n when the exposure material is irradiated n times with the ion beam to form the pattern. In the ion beam processing method for forming a predetermined pattern on the material to be exposed by irradiating the same location of the material to be exposed multiple times with the ion beam,
When the current value of the ion beam fluctuates periodically, the fluctuation period T is obtained,
Setting a reference beam wave that periodically varies in the period T;
An ion beam whose phase is shifted by a phase δ calculated from the period T with respect to the reference beam wave is prepared,
An ion beam processing method, wherein a predetermined pattern is formed by irradiating the same portion of the material to be exposed again with the ion beam whose phase is shifted. In forming the pattern by irradiating the material to be exposed n times with an ion beam,
In the case of the m-th (m ≦ n) ion beam irradiation, an ion beam shifted by a phase δ = (T / n) × (m−1) with respect to the reference beam wave is prepared,
The ion beam processing method according to claim 3, wherein the ion beam whose phase is shifted is irradiated to the same location on the material to be exposed. In the ion beam processing apparatus for forming a predetermined pattern on the material to be exposed by irradiating the same position of the material to be exposed multiple times with the ion beam,
When the current value of the ion beam periodically varies, pulsation detecting means for obtaining the variation period T;
An ion beam whose phase is shifted by the phase δ calculated from the period T with respect to the previously irradiated ion beam is prepared, and the ion beam whose phase is shifted is irradiated again on the same portion on the exposed material. Scan control means for controlling
An ion beam processing apparatus comprising: In the ion beam processing apparatus for forming a predetermined pattern on the material to be exposed by irradiating the same position of the material to be exposed multiple times with the ion beam,
When the current value of the ion beam periodically varies, pulsation detecting means for obtaining the variation period T;
Reference beam wave setting means for setting a reference beam wave that periodically varies in the period T;
An ion beam whose phase is shifted by a phase δ calculated from the period T with respect to the reference beam wave is prepared, and the ion beam whose phase is shifted is again irradiated to the same portion on the exposure object. Scan control means to control;
An ion beam processing apparatus comprising:

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