JP5135503B2 - Multivalent ion beam irradiation method and apparatus - Google Patents

Description

  The present invention relates to a method for irradiating a multi-charged ion beam that efficiently and accurately irradiates a high-power multivalent ion beam and contributes to a nanometer-size processing technique and the like, and an apparatus for performing the method.

  Multivalent ions are positive ions having only a few bound electrons, and have a large potential energy corresponding to the sum of the ionization energies of the stripped electrons.

When multiply charged ions are incident on a solid surface, the following characteristic phenomenon occurs as a result of releasing the potential energy.
1) A nanometer-sized structural change occurs in the vicinity of the incident point (Non-Patent Documents 1 and 2).
T. Meguro et al .: Appl. Phys. Lett. 79 (2001) 3866-3868. Y. Baba, K. Nagata, S. Takahashi, N. Nakamura, N. Yoshiyasu, M. Sakurai, C. Yamada, S. Ohtaniand M. Tona: Surface Sci. 599 (2005) 248-254.

2) Dozens to hundreds of secondary electrons are emitted for one multivalent ion (Non-patent Document 3).
JW McDonald, D. Schneider, MWClark and D. DeWitt: Phys. Rev. Lett. 68 (1992) 2297.

3) A sputtering phenomenon induced by electronic transition caused by the potential energy of multiply charged ions occurs (Non-Patent Documents 4 to 5).
M. Tona, S. Takahashi, K. Nagata, N. Yoshiyasu, C. Yamada, N. Nakamura, S. Ohtaniand M. Sakurai: Appl. Phys. Lett. 87 (2005) 224102. M. Tona, H. Watanabe, S. Takahashi, N. Nakamura, N. Yoshiyasu, M. Sakurai, T. Terui, S. Mashiko, C. Yamada, and S. Ohtani: Surface Sci. (Accepted)

  Such properties of multivalent ions may be applicable to nanometer-size processing technology such as single ion implantation and quantum dot fabrication, device technology, and analysis technology. However, sufficient beam intensity is not obtained with the conventional multiply charged ion source.

As conventional polyvalent ion sources, an electron cyclotron resonance ion source (ECRIS) and an electron beam ion source (EBIS) are known. EBIS is characterized by a high ionization degree of ions obtained.
The EBIS includes a cathode, a drift tube, a collector, a solenoid magnet, an ion extraction lens, and the like. Electrons emitted from the cathode pass through a drift tube arranged in a magnetic field and are collected by a collector. The electrons are compressed by a strong magnetic field formed in the drift tube and become an electron beam with a large current density. On the other hand, the gas introduced from the vicinity of the cathode is subjected to impact ionization by electrons due to a well-type potential formed in a drift tube that serves as a barrier against ions, and becomes multivalent ions.
A typical beam intensity according to the conventional EBIS is 10 ⁵ to 10 ⁶ / mm ² / s. In this case, only one or less ions are incident on a 100 nanometer square in 100 seconds.

In addition, in order to use multivalent ions for nanometer-sized processing technology, device technology, analysis technology, etc., it is necessary to control the multivalent ion beam to irradiate efficiently and accurately.
The following are related arts (Non-Patent Document 6, Patent Documents 1 to 4).
A. Persaud, FI Allen, F. Gicquel, SJPark, JA Liddle, T. Schenkel Tzv. Ivanov, K. Ivanova, IWRangelow, J. Bokor: “Single ion implantation with scanningprobe alignment”, J. Vac. Sci. Technol. B, Vol.22, No. 6, 2004. Japanese Patent Application Laid-Open No. 2006-302785 “Multivalent Ion Irradiation Apparatus and Microstructure Manufacturing Method Using It” JP2006-108054 "Multivalent ion generation source and charged particle beam apparatus using the generation source" Japanese Patent Laid-Open No. 6-326060 “Solid Surface Processing Method” JP-A-6-36735 "Substrate manufacturing apparatus and substrate manufacturing method by multivalent ion implantation method"

  For example, Non-Patent Document 6 discloses a technique of irradiating while viewing a sample shape with an AMF using a perforated cantilever, but there is no apparatus that takes into account the irradiation process of multivalent ions in the prior art, and multivalent ion irradiation. Is not efficient in each step such as generation of multivalent ions suitable for irradiation, control of multivalent ion beams, and irradiation position control. In particular, the irradiation position control was not performed at all.

  Therefore, the present invention provides a multiply charged ion source capable of obtaining a sufficient beam intensity, and controls the multiply charged ion beam, controls the irradiation position, and can irradiate efficiently and accurately. It is an object to provide a beam irradiation method and apparatus.

  In order to solve the above-described problems, the multivalent ion beam irradiation apparatus of the present invention has the following configuration. That is, a multiplicity of at least a multivalent ion source that generates multivalent ions, a beam guide that guides a multivalent ion beam derived from the multivalent ion source toward the sample, and a sample holding unit that holds the sample. In a charged ion beam irradiation apparatus, a base stage that supports a beam guide end and a sample holder facing a sample and translates and adjusts the position thereof, and a beam guide end relative to the sample holder Irradiation having an XY stage that adjusts the position by translation in two dimensions and a Z translation mechanism that adjusts the position by moving only the sample holder independently in the Z direction substantially perpendicular to the movement direction of the XY stage A position control unit is provided.

  Here, if the base stage is provided with at least one rotation mechanism that rotates and adjusts the position about a certain axis, the irradiation position control becomes more efficient.

  The XY stage may be provided with driving means for translation in steps of about 100 nm to contribute to the convenience of position adjustment.

  The apparatus may be configured by connecting a Z translational rotation introducing mechanism that transmits a driving force for translational movement and rotation in the Z direction to the base stage to the support shaft of the XY stage.

  The apparatus may be configured by connecting an XY translation introducing mechanism that transmits a driving force for translational movement in the XY direction to the base stage to the support shaft of the XY stage.

  The apparatus may be configured by connecting a Z rotation introduction mechanism that transmits a driving force for rotation in the Z direction to the sample holder on the spindle of the XY stage.

  A mask having a hole with a diameter of 10 to 100 nm may be provided at the end of the beam guide to narrow the multiply charged ion beam irradiated to the sample.

  As the mask, a mask in which holes having a diameter of about 100 nm are provided in a lattice pattern at intervals of about 300 nm can be used.

  The distance between the hole and the sample may be adjusted to 1 μm or less to suppress the angular spread of the multiply charged ion beam.

As a highly charged ion source, an electron beam with an emission current of about 100 mA or more is generated from an electron gun, accelerated to a high energy of about 10 keV or more, and maintained in an ultrahigh vacuum of about 10 ⁻⁸ Pa or less with a strong magnetic field. An EBIS type multi-charged ion source that generates multi-charged ions can be used by guiding the inside to narrow the electron beam and repeating ionization by collision with atoms and ions.

  The method of irradiating a multiply charged ion beam according to the present invention includes a multiply charged ion source that generates multiply charged ions, a beam guide that guides the multiply charged ion beam derived from the multiply charged ion source toward the sample, and the sample. In the multivalent ion beam irradiation apparatus comprising at least a sample holding unit, the beam guide end and the sample holding unit opposed to the sample are supported and translated by moving the base stage to adjust the position. The relative position between the sample holder and the beam guide end is adjusted by an XY stage that translates the sample holder and moves the beam guide end relative to the sample holder in two dimensions to adjust the position. Z-translation that adjusts the position by translating the sample holder only in the Z-direction substantially perpendicular to the movement direction of the XY stage. The movement mechanism, a sample holder of an XY stage moving direction substantially perpendicular Z direction by translation, after adjusting the irradiation position, and performing irradiation to the sample.

  Here, the base stage is provided with at least one rotating mechanism that rotates around a certain axis to adjust the position, and the base stage is rotated by the rotating mechanism so that the irradiation position can be adjusted efficiently. Good.

  EBIS type multi-charged ion source is used as the multi-charged ion source. Before the operation, the whole ion source is baked to about 200 ° C for several days and a magnetic field and an electric field are applied to the drift tube. An ultra-high vacuum state during operation may be maintained by degassing for several days.

  For the exhaust system, a turbo molecular pump and a titanium getter pump with an exhaust speed of about 300 liters / s can be used.

  The drift tube may be cooled to about 25K or less, and the residual gas in the drift tube may be degassed to contribute to the generation of an expensive number of multiply charged ions.

By maintaining an ultra-high vacuum of about 10 ⁻⁸ Pa or less while an electron beam having an emission current of about 100 mA or more is generated, an expensive number of multiply charged ions may be contributed to the generation.

  The magnetic field of the path of the electron beam in the beam guide from the multiply-charged ion source is set to 0 in the vicinity of the cathode of the electron gun, and then the intensity is increased in a substantially quadratic function to 0 in the electron recovery region of the collector. You may make it contribute to generation | occurrence | production of the stable electron beam.

Position adjustment of the electron beam path in the beam guide from the multiply charged ion source
The central axis of each electrode of the electron gun, drift tube, and collector and the magnetic field axis of the superconducting magnet may be substantially matched to contribute to the generation of a stable electron beam.

  In order to make the center axes of the electrodes coincide with each other, a viewing window may be provided on the collector side, and the position of the electron gun and the collector may be adjusted while observing with a transit that is aligned with the axis of the drift tube in advance.

  In order to make each electrode axis coincide with the magnetic field axis, the gap between the bore of the container of the superconducting magnet and the pipe of the drift tube inserted therein may be made uniform.

  By setting the potential of the drift tube to 1.5 to 3 kV and extracting the sample from the multiply charged ion source with low energy and irradiating the sample, the potential energy of the multiply charged ions may be effectively applied to the nanoprocess.

  By increasing or decreasing the valence of the multiply charged ions, the irradiation effect on the sample may be increased or decreased to contribute to an appropriate effect on the nanoprocess.

According to the present invention, a highly-charged ion beam can be efficiently and accurately irradiated by an irradiation position control device having a degree of freedom of seven axes or more. The irradiation area and the non-irradiation area of the multiply charged ions can be divided at the nanometer level, and the irradiation position in the sample can be selected and controlled at the nanometer level.
In addition, a multivalent ion source capable of obtaining a sufficient beam intensity can be obtained, and it has become possible to effectively irradiate a sample with an expensive number of multivalent ion beams.

Embodiments of the present invention will be described below with reference to the drawings. The configuration of the present invention is not limited to the following embodiments, and the design can be appropriately changed using a conventionally known technique without departing from the spirit of the present invention.
The present inventors have developed a general-purpose EBIS type multi-charged ion source that is easy to operate and maintain in addition to high beam intensity, and is inexpensive to manufacture (Non-Patent Documents 7 to 9).
M. Sakurai, F. Nakajima, T. Fukumoto, N. Nakamura, S. Ohtani and S. Mashiko: J. Phys. Conf. Ser. 2 (2004) 52-56. M. Sakurai, F. Nakajima, T. Fukumoto, N. Nakamura, S. Ohtani, S. Mashiko, H. Sakaue: Nucl. Instr. Meth. B235 (2005) 519-523. Makoto Sakurai, Fumiharu Nakajo, Takanori Fukumoto, Nobuyuki Nakamura, Shunsuke Otani, Nobuo Masuko: Vacuum 48 (2005) 317-320.

  In the present invention, a high-intensity multiply charged ion source whose beam intensity is about two orders of magnitude higher than that was developed, and a mechanism for controlling the irradiation position at the nanometer level was developed and applied to the nanoprocess.

FIG. 1 is an explanatory view showing a main part in the vicinity of a collector in an EBIS type multi-charged ion source.
The EBIS type multivalent ion source includes a cathode, a drift tube, a collector (11), a solenoid magnet, an ion extraction lens, and the like. The electrons emitted from the cathode pass through the drift tube disposed in the magnetic field and are absorbed by the collector (11). A gas introduced from the vicinity of the cathode collides with an electron beam with a large current density compressed in the drift tube, and becomes ionized by progressing ionization.

In order to generate an expensive number of multiply charged ions, it is necessary to maintain an ultrahigh vacuum (10 ⁻⁸ Pa or less) while an electron beam having a large emission current (100 mA or more) is generated. During operation of the ion source, in addition to degassing by electron-excited desorption from the collector (11) that collects the electron beam, degassing by penning discharge of electrodes in a strong electric field / strong magnetic field, and by the heat of the cathode heater There are many factors that deteriorate the degree of vacuum, such as heat degassing of the electron gun section, and it is not easy to maintain an ultra-high vacuum.

In this equipment, before operation, the entire ion source is baked at 200-250 ° C for about 5 days, then the drift tube is applied with a magnetic field of 2T and a voltage of 5kV, and degassing is carried out for 1-2 days by penning discharge. Due to the treatment, an ultrahigh vacuum of 10 ⁻⁸ Pa or less is maintained even during operation. For the exhaust system, a turbo molecular pump and a titanium getter pump with an exhaust speed of 300 liters / s are used.

In the EBIS type multiply charged ion source, an electron beam with an emission current of 100 mA or more is generated from an electron gun, accelerated to high energy (10 keV or more), guided into a strong magnetic field, and focused by collision with atoms and ions. Multivalent ions are generated by repeated ionization.
Most of the electron beams pass through the multiply-charged ion generation region without colliding and are collected by the collector (11). All of the electrons emitted from the cathode need to be collected by the collector (11). However, if the electromagnetic field distribution is poor, the electrons do not take an ideal trajectory, so the electron gun returns to the electron gun side from the collector region. Collide with each electrode. Due to the heating effect and the like, it may be impossible to generate an electron beam stably.

The condition for the electron to take an ideal orbit is that the magnetic field is zero near the cathode, then the magnetic field is suddenly raised (in a quadratic function), and the magnetic field is also zero in the electron recovery region of the collector (11). That is.
In order to realize this condition, the following improvements were made. 1) Move the electron gun away from the conventional superconducting magnet about 90mm, 2) Reduce the diameter of the magnetic body of the electron gun magnetic shield to about 6mm to make the rise of the magnetic field sufficiently steep, and 3) Collector (11) To increase the thickness of the magnetic shield (12), 4) to provide a collector coil as an electromagnet inside the magnetic shield (13), and 5) to suppress the return of electrons from the collector (11) to the electron gun side The number of suppressor electrodes (14) was increased to two, and 6) the diameters of the suppressor and extractor (15) were narrowed down.

With this improvement, the emission current of the electron beam reached 180mA.
By increasing the thickness of the magnetic shield (12) of the collector (11), the weight of the collector portion is increased, and the force with which the magnetic shield (12) is attracted to the magnet during excitation of the superconducting magnet is also increased. The supporting ceramic rod (16) was thickened and reinforced.

Another condition for the electron to take an ideal trajectory is that the central axis of each electrode of the electron gun, drift tube and collector (11) and the magnetic field axis of the superconducting magnet are matched within a certain error. is there.
In order to realize this condition, the central axis of each electrode has a viewing window on the collector (11) side, and the position of the electron gun and collector is adjusted while observing with a transition that is aligned with the axis of the drift tube in advance. The error was kept within 0.1mm.
The positional relationship between the electrode axis and the magnetic field axis was adjusted by a method in which the gap between the bore of the superconducting magnet container and the drift tube pipe inserted therein was made uniform.
Finally, an electron beam and an ion beam were actually generated and finely tuned to show the best performance with high electron beam recovery and high ion valence and strength.

FIG. 2 is an explanatory diagram showing a main part in the vicinity of the beam line in the EBIS type multiply charged ion source.
A pipe (beam line) provided with an electron lens (21), an analysis magnet (22), various detectors, etc. is connected to the downstream side of the ion source, and direct current is supplied from the ion source at each stage of the ion source startup described above. The mass spectrum of multiply charged ions was measured. For the measurement of the beam intensity, a Faraday cup (24) provided immediately after the outlet slit (23) of the analysis magnet (22) was used.
As a result, the ion beam intensity and valence distribution change significantly due to a slight deviation between the magnetic field axis and the electrode axis, and the generation of expensive ions is hindered by residual gas with a total pressure of about 5 × 10 ⁻⁸ Pa. I understood it. However, this pressure is a value measured by a vacuum gauge attached to the collector, and the pressure inside the drift tube is considered to be higher than this value.

Obtained by introducing 5 × 10 ⁻⁸ Pa of argon gas under conditions where the magnetic field axis and electrode axis are almost aligned at an electron beam current of 150 mA, an electron beam energy of 20 keV, and a magnetic flux density of 3 T at the drift tube center using a superconducting magnet. The intensity of the multiply charged ions was about ⁹ nA for Ar ^{9+ and} about 2 nA for Ar ¹²⁺ (10 ⁹ to 10 ¹⁰ / s in number).

The obstacle to the generation of expensive ions is the residual gas in the drift tube, and it is considered that the most effective method for reducing this pressure is to cool the drift tube. Degassing during the electron beam occurs because CO, CO ₂ is large, CO can be expected a significant effect if cooled to the following areas 25K to condense.

The electron beam energy is determined by the potential difference between the cathode of the electron gun and the drift tube, but the energy of the extracted ions is proportional to the potential of the drift tube.
In order to apply the effect of the potential energy of multiply charged ions to the nanoprocess, it is desirable that the kinetic energy of the ions when irradiating the sample is low, and the ions extracted from the ion source at a high speed are decelerated and irradiated. As a result, the beam is diverged, and irradiation with high density becomes impossible.
Therefore, it is desirable to extract from the ion source with as low energy as possible. In this device, it was found that the same ionic current can be obtained in the drift tube potential range of 1.5 to 3 kV.

The multivalent ion beam extracted from the ion source is focused through a mask having holes, and then irradiated onto the sample.
FIG. 3 is a front view of the mask and a side sectional view in which a part thereof is enlarged.
In the substantially disk-shaped mask (31), holes (32) having a diameter of several tens to 100 nm are periodically arranged. For example, circular holes having a diameter of 100 nm arranged in a square lattice at 300 nm intervals can be used.
The mask (31) only needs to allow the multivalent ion beam to pass through the hole (32), and is configured to be detachable so that the shape and the shape and arrangement of the holes (32) can be changed as appropriate according to the application. It is preferable to do.

FIG. 4 is an explanatory diagram showing the spread of the beam according to the distance between the mask and the sample.
The multivalent ion beam is focused by the mask (31) to a nanobeam having a diameter of the hole (32). However, if the distance D between the mask (31) and the sample (100) is separated, the beam divergence affects. The beam size on the sample (100) will spread.
Assuming that a distance D is required for the multiply charged ion beam having the angular spread θ to pass through the hole (32) having the diameter d and reach the sample (100), the angular spread when reaching the sample (100) is Dθ. In order to make this angular spread Dθ smaller than the diameter d of the hole (32), if θ = 0.01 rad and d = 10 nm, it is necessary that D <1 μm.

That is, in order to suppress the angular spread of the multiply charged ion beam, a position adjusting mechanism for bringing the mask (31) closer to the sample (100) within 1 μm is necessary.
In addition, the mask (31) and the sample (100) each need a mechanism for aligning with the multiply-charged ion beam, and the sample (100) is subjected to surface cleaning treatment, LEED, STM observation, etc. It must also be transportable.
A position adjusting mechanism for the mask (31) and the sample (100) satisfying these requirements was manufactured.

5 and 6 are a front view and a partial side sectional view of the mask installed in the mask holder (33). FIGS. 7 and 8 are a side sectional view and a partial front view of the main part showing the position adjusting mechanism in the vicinity of the mask holder (33), and FIGS. 9 and 10 are explanatory views and perspective views showing the main part of the irradiation position control device. FIG.
In FIG. 9, the XY stage (34) in which the mask (31) is translated by a piezo motor in the vicinity of a few nm from the sample (100) is not shown, and in FIG. 10, the mask (31) is shown. It has not been.

As shown in FIG. 9, the support shaft (36) of the XY stage (34) is connected to the translation / rotation introduction mechanism (51) via the translation bearings (41) and (42) and the spur gear train (43). Has been. This translational rotation introduction mechanism (51) introduces translational movement and rotation in the Z direction into the mask (31) and the sample (100).
The support shaft (36) of the XY stage (34) includes a translation introduction mechanism (52) and a rotation introduction mechanism via a translation bearing (41), a rack-pinion (44), a sprocket-chain (45), and the like. (53). Depending on the translation introducing mechanism (52), translational movement in the XY direction is introduced into the mask (31) and the sample (100), and depending on the rotation introducing mechanism (53), the sample (100) is introduced into the Z direction. Rotation is introduced.

In this way, the irradiation position control device is a Z moving mechanism for the sample (100) only on the stage having the translational movement in the XYZ directions and the degree of freedom of rotation about the vertical axis on the base of the mask (31) and the sample (100). And an XY stage (34) capable of driving the mask (31) in steps of 100 nm with respect to the sample (100).
The irradiation position control device having seven degrees of freedom is mounted on an ICF356 standard flange, and translational movement and rotation introduction mechanisms (51), (52) and (53) for driving are also attached to the same flange.

In the prior art, there was a translation movement in the XYZ directions by the translation movement introduction mechanism, but this apparatus is not only a combination of these, but also a rotation introduction mechanism or a translation movement introduction of only the sample (100). By attaching the mechanism so that other degrees of freedom are not impaired, the position of the mask (31) can be finely adjusted in the vicinity of the sample (100).
As a result, the irradiated region and non-irradiated region of multivalent ions can be divided at the nanometer level, and the irradiation position in the sample (100) can be selected and controlled at the nanometer level.

Although the irradiation position control apparatus of the above-mentioned embodiment has 7 degrees of freedom, the drive control of the mask (31) and the sample (100) has 7 to 8 axes, and the relative positions of the mask (31) and the sample (100). It is desirable to provide 2-3 axes for control.
In addition, conventionally known technology using a piezo motor, a stepping motor, or the like can be appropriately used for drive control for introducing translational movement and rotation. Conventionally known techniques such as a rack-pinion and a sprocket-chain can be used as appropriate as the driving force transmission means.

Using an electron beam accelerated to 3 × ^q keV by multiply charged ions (I ^{q +} ), the sample was irradiated and subjected to STM observation in a chamber decompressed to 2 × 10 ⁻⁸ Pa.
The mask used was a SiO ₂ thin film with a large number of 100 nm holes arranged.

FIGS. 11 and 12 are STM images and depth profiles showing the result of irradiating the surface of Si (1 1 1) − (7 × 7) with an I ⁵⁰⁺ multivalent ion beam.
The crater portion displayed in black in FIG. 11 indicates peeling of the upper layer of the sample, and its area is 5.5 nm ² and the depth reaches 0.35 nm.
The same experiment was performed by changing the valence of the multiply charged ion beam in the range of 30-50. As a result, it has been found that the volume of the crater portion increases rapidly as the valence increases.

FIGS. 13 and 14 are STM images showing the result of irradiating a highly oriented pyrolyticgraphite (HOPG) surface with a highly charged ion beam of I ³⁰⁺ , and STM images showing the result of coating with Bis-MSB after irradiation. is there.
As shown in FIG. 13, irradiation produced dots of several nanometers that were irregularly dispersed on the surface layer of HOPG.
As shown in FIG. 14, the dot was enlarged to about 10 nm by the Bis-MSB coating. This is because Bis-MSB was accumulated in the dots, and irradiation of the multiply charged ion beam resulted in activation of the nanospot.

  According to the present invention, the irradiation position of an expensive number of multiply charged ion beams can be controlled at the nanometer level. Therefore, it can be applied as various nanodevice fabrication techniques, including irradiating a solid surface to induce structural transformations such as nanodots, and has high industrial utility value.

Explanatory drawing which shows the principal part near the collector in the EBIS type multiply charged ion source Explanatory drawing which shows the principal part near the beam line in the EBIS type multiply charged ion source Front view of the mask and side cross-sectional view of a part of it Explanatory drawing showing the spread of the beam depending on the distance between the mask and the sample Front view of the mask installed in the mask holder Partial side sectional view of the mask installed in the mask holder Side sectional view of the main part showing the position adjustment mechanism near the mask holder Partial front view showing the position adjustment mechanism near the mask holder Explanatory drawing showing the main part of the irradiation position control device Perspective view (photo) showing the main part of the irradiation position control device STM image showing the result of irradiating the surface of Si (1 1 1)-(7x7) with I ⁵⁰⁺ multiply charged ion beam Same as above, depth profile STM image showing the result of irradiating the surface of the HOPG with a highly charged ion beam of I ³⁰⁺ STM image showing the result of coating with Bis-MSB after irradiating the surface of HOPG with a highly charged ion beam of I ³⁰⁺

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Collector 12 Magnetic shield 13 Collector coil 14 Suppressor electrode 15 Extractor 16 Ceramic support rod 21 Electron lens 22 Analysis magnet 23 Exit slit 24 Faraday cup 25 Inlet slit 26 Faraday cup 27 Gate valve 28 Secondary electron detection part 31 Mask 32 Hole part 33 Mask holder 34 XY stage 35 Lens electrode 36 Support shafts 41, 42 Translation bearing 43 Spur gear train 44 Rack-pinion 45 Sprocket-chain 51 Translation rotation introduction mechanism 52 Translation introduction mechanism 53 Rotation introduction mechanism 100 Sample 101 Sample holder

Claims (17)

Multivalent ions comprising at least a multivalent ion source for generating multivalent ions, a beam guide for guiding a multivalent ion beam derived from the multivalent ion source toward the sample, and a sample holding unit for holding the sample In the beam irradiation device,
A base stage that supports the beam guide end and the sample holder facing the sample and adjusts the position by translation in the three-dimensional XYZ direction and rotation in the Z direction, and translation in the Z direction to the base stage And a Z translation rotation introduction mechanism that independently transmits the driving force of rotation, and an XY translation introduction mechanism that independently transmits the driving force of translational movement in the XY directions,
An XY stage that adjusts the position by moving the beam guide end relative to the sample holder relative to the two-dimensional XY direction, and Z rotation that independently transmits the driving force for rotation in the Z direction to the XY stage. An introduction mechanism;
An irradiation position control unit having a Z translation mechanism for adjusting the position by independently translating the sample holder in the Z direction and a Z rotation introduction mechanism for independently transmitting a driving force for rotation in the Z direction is provided. A multivalent ion beam irradiation apparatus characterized by that. The multivalent ion beam irradiation apparatus according to claim 1, wherein the XY stage is provided with a drive unit that translates in steps of about 100 nm. The multivalent ion beam irradiation apparatus according to claim 1, wherein a mask having a hole having a diameter of 10 to 100 nm is provided at an end of the beam guide. The multivalent ion beam irradiation apparatus according to claim 3, wherein holes having a diameter of about 100 nm are provided in a mask in a lattice pattern at intervals of about 300 nm. The multivalent ion beam irradiation apparatus according to claim 3 or 4, wherein the distance between the hole and the sample can be adjusted to 1 µm or less. In the multiply charged ion source,
The emission current of about 100mA or more electron beams are generated from the electron gun, about accelerated to high energy over 10 keV, while maintaining the following ultra-high vacuum of about 10- ⁸ Pa, electrons induced in a strong magnetic field beam the diaphragm, polyvalent ion beam irradiation device according to any one of claims 1 provided EBIS polyhydric ion source for generating multivalent ions by repeating the ionization due to collision with atoms and ions 5. Multivalent ions comprising at least a multivalent ion source for generating multivalent ions, a beam guide for guiding a multivalent ion beam derived from the multivalent ion source toward the sample, and a sample holding unit for holding the sample In the beam irradiation device,
The beam guide end and the sample holder are supported by a base stage that supports the beam guide end and the sample holder facing the sample and adjusts the position by translation in the three-dimensional XYZ direction and rotation in the Z direction. Translate and rotate in the Z direction,
The relative position of the sample holder and the beam guide end is translated in two dimensions by an XY stage that adjusts the position by moving the beam guide end relative to the sample holder relative to the two-dimensional XY direction. ,Also,
The sample holder is moved in the XY stage by a Z translation mechanism for adjusting the position by independently moving the sample holder in the Z direction and a Z rotation introduction mechanism for independently transmitting a driving force for rotation in the Z direction. Translate and rotate in the Z direction, approximately perpendicular to the direction,
A method of irradiating a sample after adjusting the irradiation position, wherein the sample is irradiated. In the multivalent ion source, an EBIS type multivalent ion source is provided,
Before the operation, the entire ion source is baked at a temperature of about 200 ° C for several days, and a degassing treatment is performed by performing discharge cleaning by Penning discharge for several days with a magnetic field and electric field applied to the drift tube. The multivalent ion beam irradiation method according to claim 7, wherein a vacuum state is maintained. The multivalent ion beam irradiation method according to claim 7 or 8, wherein a turbo molecular pump and a titanium getter pump having an exhaust speed of about 300 liters / s are used for the exhaust system. The method according to any one of claims 7 to 9, wherein the drift tube is cooled to about 25K or less to degas the residual gas in the drift tube. In a state that caused the emission current of about 100mA or more electron beams, by maintaining the following ultra-high vacuum of about 10- ⁸ Pa, according to any one of claims 7 to 10 to generate multivalent ions Multivalent ion beam irradiation method. The magnetic field of the electron beam path in the beam guide from the multiply charged ion source,
The multivalent ion beam according to any one of claims 7 to 11, wherein the magnetic field is set to zero near the cathode of the electron gun, and then the intensity is increased approximately quadratic to a magnetic field of zero in the electron recovery region of the collector. Irradiation method. Position adjustment of the electron beam path in the beam guide from the multiply charged ion source
The method for irradiating a multivalent ion beam according to any one of claims 7 to 12, wherein a central axis of each electrode of the electron gun, drift tube, and collector is substantially coincident with a magnetic field axis of a superconducting magnet. The sighting window is installed on the collector side, and the position of the electron gun and the collector is adjusted while observing with a transit previously aligned with the axis of the drift tube, so that the central axes of the electrodes coincide with each other. Multivalent ion beam irradiation method. The multivalent ion beam irradiation method according to claim 13, wherein the electrode axes and the magnetic field axes are made to coincide with each other by making the gap between the bore of the superconducting magnet container and the piping of the drift tube inserted therein uniform. . The potential of the drift tube as 1.5～3KV, pull at low energy from multivalent ion source, polyvalent ion beam irradiation method according to any one of claims 7 to 15 is irradiated to the sample. The method according to any one of claims 7 to 16, wherein the volume of the sample to be peeled is increased or decreased by increasing or decreasing the valence of the multiply charged ions.

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